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  • Munksgaard International Publishers  (320)
  • 1990-1994  (320)
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  • 101
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 102
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 103
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A field experiment evaluated the effect of a furniture-inte-grated breathing-zone filtration (BZF) system on indoor air quality, worker comfort, health, and productivity. The BZF system tested filters office air to remove volatile organic compounds and airborne particulates. The BZF system was installed on one floor of a 29 story air-conditioned office building. Another floor of the building served as a control. Comparisons of pre-installation and three month post-instal-lation surveys showed improvements in indoor air quality, sick building syndrome symptoms, and self-reported pro-ductivity with the BZF system References
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  • 104
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A “fungal index” is proposed as a new climate parameter for the characterization of the indoor environment. The index quantifies the environmental conditions in relation to the ability of fungi to grow by means of the response of a xerophilic fungus Eurotium herbariorum. The growth response of this fungus was found to be climate-dependent. The indoor environment in a residential building in Japan (1991-1992) was quantitatively assessed by this approach. In the assessment, the variation in microclimate, which differs greatly within and between rooms, could be demonstrated.
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  • 105
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: An environmental assessment of Legionella bacteria was conducted in five office buildings in the continental United States where no legionellosis was reported. The purpose of this investigation was to (i) determine the presence of Legionella bacteria in potable and non-potable water systems, (ii) provide a baseline information for management, and (iii) evaluate the effectiveness of the remedial actions taken. Water samples were collected from all possible water sources in surveyed buildings. The samples were analyzed by both direct fluorescent antibody microscopy (DFA) and the bacterial cultural method for the presence of Legionella species. Legionella bacteria were detected in some samples collected from various water distribution systems in the buildings. Remedial action was taken to eliminate these bacteria, and case-by-case results are presented.
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  • 106
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: An empirical statistical model is described for the use of indoor radon monitoring data as an indicator of the areal radon risk from soil and bedrock. The percentages of future homes expected to have radon concentrations exceeding the design level of 200 Bq/m3 unless constructed to provide protection against the entry of radon were assessed. The radon prognosis was made for different subareas, soil types and foundation types. This kind of report is used by the health and building authorities.In this study, 2689 indoor radon measurements were made in one of Finland's most radon-prone areas, consisting of eleven municipalities with a total area of 4600 km2 and a population of 186,000. Radon concentrations were seasonally adjusted. Data on the location, geology and construction of buildings were determined from maps and questionnaires. The measurements covered different kinds of geological units in the area.The radon risk is highest in the gravel-dominated subarea in an ice-marginal formation and lowest in the northern half of the area in buildings constructed on bedrock. In these two areas, the design level of 200 Bq/m3 would be exceeded in 99% and 39% of new houses with slab-on-grade.
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  • 107
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 108
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: As part of the energy and indoor climate survey recently carried out in Sweden (the ELIB study) a simple, inexpensive but reliable passive sampler for estimating monthly averages of relative humidity has been developed. The diffusion sampler consists of a 5 ml plastic tube prepared with lithium chloride monohydrate (LiCl. H2O) as trapping medium. After necessary calibration of this particular design of sampler the relative humidity can be calculated from the weight change of the sampler, the time of sampling and the average temperature during this period. The estimated accuracy of the method is better than k 2% RH up to65% RH.
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  • 109
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The objective of this study was to assess the effect of air humidification and temperature on thermal comfort in sedentary office work. A blinded twelve-period cross-over trial was carried out in two similar wings of an office building, contrasting 28–39% steam humidification with no humidification, corresponding to 12–28% relative humidity. The length of each period was one working week. The study population was 169 workers who judged their thermal sensations in a weekly questionnaire. The percentage of dissatisfied was lowest when the air temperature was 22 °C. At 22 °C an increase in relative humidity raised the mean thermal sensation only slightly. At 20 °C when the air was humidified there were fewer workers who judged their air temperature as being too low. On the other hand, at 24 °C humidification increased the percentage of workers who judged their air temperature to be too high. The percentage of dissatisfied increased rapidly when the air temperature was outside of its optimum value, 22 °C. The percentage of workers complaining about draft increased when the air temperature was lower than 22 °C. Thus we consider that the temperature range from 20 to 24 °C during wintertime may be too wide without individual temperature control from the point vzew of thermal comfort. We recommend that the air temperature should be kept between 21 and 23 °C if no individual control is available. The best solution would be individual temperature control permitting adjustment of the temperature at 22 ± 2 °C.
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  • 110
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 111
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Ten healthy humans were exposed to combinations of volatile organic compounds (VOCs) and air temperature (0 mg/m3 and 10 mg/m3 of a mixture of 22 volatile organic compounds and 18, 22 and 26° C). Previously demonstrated effects of VOCs and thermal exposures were replicated. For the first time nasal cross-sectional areas and nasal volumes, as measured by acoustic rhinometry, were shown to decrease with decreasing temperature and increasing VOC exposure. Temperature and pollutant exposures affected air quality, the need for more ventilation, skin humidity on the forehead, sweating, acute sensory irritation and possibly watering eyes in an additive way. Interactions were found for odor intensity (p = 0.1), perceived facial skin temperature and dryness, general well-being, tear film stability, and nasal cavity dimension. The presence of interactions implies that in the future guidelines for acceptable indoor air concentrations of VOCs should depend on room air temperature.
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  • 112
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A questionnaire on health symptoms, workplace conditions, and perceived indoor air quality was administered to 3948 employees of the Environmental Protection Agency in Washington, DC in the winter of 1989. The main goal was to determine the personal or workplace characteristics associated with health symptoms.A principal components analysis of 32 health symptoms identified 12 health factors. Each factor was generally associated with a particular body system (eyes, nose, throat, chest, central nervous system, etc.). The 12 health factors were regressed linearly on the 50-100 personal, workplace, and spatial characteristics identified from the questionnaire and building blueprints. Significant variables (p 〈 0.01) were included in a second logistic regression to determine a final model.Eleven variables were associated with multiple health factors. The main workplace variables were dust and glare. Personal characteristics of importance were mold allergies and sensitivity to chemicals. Among women, lack of a college degree was an important factor. Air quality factors of importance included hot stuffy air and dry air: The odor of paint and other chemicals, and the odor of cosmetics were also associated with four or more of the health factors. Two measures of stress – heavy workload and conflicting demands – were also associated with several health factors.
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  • 113
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: In order to investigate the health effects of NO2, emitted from gas cooking stoves, we compared the prevalence of several respiratory symptoms for people living in gas homes (homes with gas cooking stoves) with those for people living in electric homes (homes with electric cooking stoves) in Japan. The survey was conducted in September 1985, with a self-administered questionnaire. No statistically significant differences were found for several respiratory symptoms between electric homes and gas homes among both children (adjusted odds ratios: 0.64–1.80) and their parents (odds ratios: 0.39–0.94). This work represents a preliminary study in Japan. A longitudinal study should be conducted to further investigate the health effects associated with gas cooking stoves.
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  • 114
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 115
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 116
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Total volatile organic compounds (TVOC) are determined in intake, room-supply and room air in 86 office rooms in 29 office buildings in northern Sweden. Measurements of formaldehyde were also made in room air. Building and room characteristics were identified and symptom reports collected from 1087 office workers. Concentrations of TVOC and formaldehyde in room air were low, with mean values of 71 µg/m3 and 31 µg/m3, respectively. The TVOC concentration was generally lower in room air than in supply air or intake air. The “loss” (difference in measured values) of TVOC from supply to room air was associated with raised concentrations of formaldehyde and raised prevalences of occupant symptoms. High TVOC concentrations in room air were associated with reduced prevalences of occupant symptoms.
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  • 117
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The emission of volatile organic compounds (VOC) from nine toner powders and eleven types of processed paper from photocopying machines (6), laser (3) and matrix printers (21, and one carbonless copy fm has been measured. A total of 61 VOC from toner powders were identified by heating (185 °C) the powder for three minutes for thermal desorption and by gas chromatography followed by the use of low and high resolution EI and CI mass spectrometry. VOC from processed paper were analyzed by headspace sampling on Tenax TA from nylon bags. Thirty-one VOC with a wide range of volatility and persistency were identified from processed paper. The total VOC emission from the various types of paper differed substantially. Using the field and laboratory emission cell (FLEC), the calculated initial emission rate of styrene was 5 μg m−2h−1 from a freshly processed paper The VOC emission from machines and the processed paper can be reduced by proper choice of o m e equipment. However, an evaluation should consider all potential pollutants.
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  • 118
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: In a subarctic climate the diurnal variation in temperature may cause water condensation in ducts placed in the unheated spaces of a building. In this study, germination time and sporulation of a fungus, Penicillium verrucosum, were studied on dusty, galvanized steel sheet under different moisture conditions at room temperature. The effect of condensed water in a supply air duct on spore amplification was studied in an experimental ventilation set-up. In the field, air temperatures and the dew point temperature of air in the duct were monitored continuously for a week. P. verrucosum germinated on steel surfaces during five-hour incubation of the surface under humid conditions; when the surface had been moist for half an hour, germ tubes appeared within 17 hours. During 24-hour incubation under moist conditions, P. verrucosum produced hypae and spores. In the experimental set-up the airborne spore counts increased when the air passed through a water-condensingsection of the duct. Penicillium was the most abundant fungus sporulated on the moist duct surface. In the field, during humid weather, the surface temperature on the air stream surface decreased to the dew point temperature of the air in the duct. Thus water condensation in air ducts may promote fungal growth.
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  • 119
    Electronic Resource
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The sampling rate of a nitrogen dioxide (NO2) passive sampling badge was evaluated in indoor environments including an unoccupied research house, residential houses, and an office. Measurements from the NO2 badges were compared with those of a chemiluminescent analyzer the EPA reference method, by placing them near to the sample inlet of the chemiluminescent analyzer In this study, we used a new sampling rate for the NO2 badge placed in indoor environments (an overall mass transfer coefficient of 0.10 cm/s) smaller than the rate previously reported for the badge when used outdoors. The new rate provides more accurate measurements of NO, concentrations in indoor environments. Indoor NO2 concentrations were also measured with the NO2 badges exposed to a constant wind velocity provided by a wind tunnel. Since the measurements of the badge with a constant wind velocity agreed well with the reference method, the badges could be assumed to be a secondary reference measurement. With the badges used as the secondary reference measurement, we developed a portable wind tunnel to evaluate a personal exposure measurement by the badge. The results are presented in Environment International (Lee et al., 1993). Precision of the badge measurements was as good as an intraclass correlation coefficient of 0.9779. It was determined that placement of the badge should be at least 10 cm out from an indoor wall surface to avoid undersampling due to NO2 gradients near the surface.
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  • 120
    Electronic Resource
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The effect of a thin, passive, adsorbent sheet containing activated carbon on reducing the concentration of volatile organic compounds in indoor air is investigated. A mathematical model is established to describe the conditions in a hypothetical room containing building materials, furniture, an activated carbon sheet, etc. The results of the modelling show that the activated carbon sheet can reduce the concentration of the organic vapour in the room air by a factor of 1.6 – 200, depending on the resistances to mass transfm in the laminar gas film surrounding the activated carbon sheet and in the voids of the sheet. The maximum value 200 is a theoretical limit, if both the film and void resistances could be eliminated. Minimization of the film and void resistances is important to achieve high effect of the activated carbon sheet. This could be done by e.g. dividing a single sheet into several smaller pieces, hanging the sheets at some places where the airflow is relatively high, and making the sheets thin and loose. For some of the model parameters, estimated or assumed values were used in the calculations. Experimental work regarding sorption equilibria and mass transport properties of the species and materials involved is needed for more accurate results.
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  • 121
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Epidemiologic research into the causes of non-specific symptoms among office workers has produced a variety of conflicting findings which are difficult to synthesize. This paper first discusses methodologic issues important in the interpretation of epidemiologic studies, and then reviews the findings of 32 studies of 37 factors potentially related to office worker symptoms. Among environmental factors assessed, there were generally consistent findings associating increased symptoms with air-conditioning, carpets, more workers in a space, VDT use, and ventilation rates at or below 10 liters/second/person. Studies with particularly strong designs found decreased symptoms associated with low ventilation rate, short-term humidification, negative ionization, and improved office cleaning, although studies reviewed showed little consistency of findings for humidification and ionization. Relatively strong studies associated high temperature and low relative humidity with increased symptoms, whereas less strong studies were not consistent. Among personal factors assessed, there were generally consistent findings associating increased symptoms with female gender, job stress/dissatisfaction, and allergies/asthma. For other environmental or personal factors assessed, findings were too inconsistent or sparse for current interpretation, and there were no findings from strong studies. Overall evidence suggested that work related symptoms among office workers were relatively common, and that some of these symptoms represented preventable physiologic effects of environmental exposures or conditions. Future research on this problem should include blind experimental and case-control studies, using improved measurements of both environmental exposures and health outcomes
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  • 122
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Twelve public office buildings were selected for a study of relationships between worker's health symptoms and a number of building, workspace, job, and personal factors. Three buildings were naturally ventilated, three were mechanically ventilated, and six were air conditioned. Information on the prevalences of work-related symptoms, demographics, and job and personal factors were determined via a questionnaire completed by 880 occupants. Several indoor environmental parameters were measured. Logistic regression models were used to evaluate associations between symptom prevalences and features of the buildings, indoor environments, jobs, and personal factors. A substantial fraction of the occupants in these typical office buildings reported frequent work-related symptoms. The occupants of the mechanically ventilated and air conditioned buildings had sipifcantly more symptoms than occupants of the naturally ventilated buildings after adjustment for confounding factors. Increased prevalences of some symptoms were associated with several job and workspace factors including: presence of carpet, increased use of carbonless copy paper and photocopiers, space sharing, and distance from a window
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  • 123
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Emissions from freshly applied paints and other coatings can cause elevated indoor concentrations of vapor-phase organics. Methods are needed to determine the emission rates over time for these products. Some success has been achieved using simple first-order decay models to evaluate data from small dynamic test chambers. While such empirical approaches may be useful for assessing the emission potmial of indoor sources, a more fundamental approach is needed to fully elucidate the relevant mass transfer processes. As a first step, a simple model based on boundary layer theory has been developed. In this model, the mass transfer rate is assumed to be controlled by the boundary layer mass transfer coefficient, the saturation vapor pressure of the material being emitted, and the mass of volatile material remaining in the source at any point in time. Static and dynamic chamber tests and test house experiments were conducted to obtain model validation data, Preliminary validaion results indicated that the model can be applied to different products with similar solvents. The model provides a better fit to chamber-derived emissions data than the empirical first-order decay model, especially over the decaying portion of the concentration vs. time curve
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  • 124
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: There is evidence that sick building syndrome (SBS) is caused, in part, by indoor surface pollution (ISP): contaminants such as dust, fibres and micro-organisms, deposited on or in surfaces in buildings. A study is described which clarifies the relative importance of a number of possible causes of SBS in a single building. The building, which had a high initial prevalence of SBS symptoms, was used in a doubleblind controlled intervention study with weekly symptom questionnaires. The four interventions were: ventilation system cleaning, air filtration, hot-water extraction cleaning of chairs and carpets, plus high grade filter vacuuming and dusting, and dust mite treatment (application of liquid nitrogen). Only the last two interventions brought about a reduction in symptoms. It is concluded that cleaning which effectively reduces ISP can reduce SBS symptoms. This may be related to the presence of dust mites in furnishings. Improved cleaning may entail better cleaning specifications and/or consideration of requirements for cleaning when selecting and positioning office furniture. If ISP and the temporary local pollution levels created by it are a problem, then monitoring of ambient conditions (by instruments or by human assessors) will not adequately represent the conditions to which occupants are exposed
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  • 125
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The relative importance of sensory air pollution, thermal load and noise was studied under controlled conditions in two identical environmental chambers. In one chamber subjects were exposed to various levels of either thermal load or poor indoor air quality. For each condition tested in this chamber, the subjects were exposed to a number of noise levels in an adjacent chamber with neutral thermal conditions and good indoor air quality in order to determine a noise level causing the same degree of discomfort. A total of 68 comparisons of the conditions in the two chambers were made by the same group of 16 subjects after one-minute exposure in each chamber. In the operative temperature range of 23–29°C, a 1°C change in operative temperature was found to have the same effect on human comfort as a change in perceived air quality of 2.4 decipol or a change in noise level of 3.9 dB. For levels of perceived air quality up to 10 decipol, a 1 -decipol change in perceived air quality had the same effect on human comfort as a change in noise level of 1.2 dB. A relationship between traffic noise level and percentage dissatisfied was established
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  • 126
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Adsorption, desorption and chemisorption are known to impact the dispersal of volatile organic and chemically reactive compounds in buildings. These same three processes may be used to advantage to control the levels of these compounds indoors using building sorption filtration devices. To add to the understanding of these processes, to provide the means to predict the impact of these processes on human exposure and to provide the tools needed to design gaseous filtration systems to mitigate the exposure to these compounds, a general approach to modeling the dynamics of these processes is presented. Equations are presented to account for the elemental advection, diffusion, sorption, and chemical transport steps affecting single component sorption dynamics in rooms and sorption filtration systems. These element equations are based on general principles and formulated in terms of fundamental physical parameters that may be determined using standard procedures. Models to predict room and sorption filtration system dynamics are formulated using assemblages of these element equations and a series of simplified models of these systems are derived. Initial applications to model single-component sorption transport in rooms and sorption filtration systems indicate that the approach has the potential to provide accurate predictions providing the sorption and chemical characteristics of the sorbate-sorbent system being considered are well-characterized. This potential is, however, compromised by the lack (or present uncertainty) of fundamental data relating to sorption equilibrium, porous diffusion, surface chemistry, and boundary layer mass transport
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  • 127
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The aim of the present study is to demonstrate the technical feasibility of the membrane absorber as an air cleaner with small-scale modules. Six small-scale membrane modules with different fibre lengths and fibre diameters have been investigated. Each module has been tested as a membrane absorber treating air with 4 different chemicals, formaldehyde, nitrogen dioxide, ammonia and acetone, with tap water. The pressure drop and the filtration efficiency has been measured at different flow rates. From these results the optimal membrane module has been selected for the following reasons: low pressure drop, small required membrane surface area and high filtration efficiency. The experiments were continued with the selected module for ETS in a test room. Water soluble compounds were removed with an efficiency of at least 95%. The efficiency was inconsistent for NO, (not expected) and low for hydrocarbons (as expected). The sensory filtration efficiency was also measured with two different methods, the threshold method and the decipol method. Both efficiencies were about 50%. Recommendations for future research are given.
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  • 128
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The purpose of this study was to characterize mold problem buildings by determining concentrations and flora of viable fungi. The composition and concentrations of fungal flora in mold problem (n = 9) and reference buildings (n = 9) were determined by means of four different sampling methods: six-stage impactor (Andersen sampler), sedimentation plate, surface and house dust samples. Samples were taken in the fall and in the winter, and the concentrations and flora in mold problem buildings were compared with those of matched reference buildings. The differences between mold problem and reference buildings were most clearly seen with the impactor samples. The total concentrations of airborne fungi were higher in moldy buildings. In addition, the concentrations of the genera Aspergillus and Oidiodendron in the fall and the concentrations of Aspergillus and Penicillium in the winter were higher in mold problem than in reference buildings. In the winter, certain fungal genera (Stachybotrys, Acremonium, Oedocephalum and Botryosporium) were detected only in the problem buildings in impactor samples. These results indicate that there may be an unusual composition of fungal flora in mold problem buildings. The results of the sedimentation plate samples showed a trend similar to that of impactor samples in the winter. In addition, the results of surface samples supported the data on the fungal flora in the winter-time air samples. The house dust samples did not reveal any differences between mold problem and matched reference buildings.
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  • 129
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    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Water used to control a fire on an upper floor in a highrise office building wetted furnishings and construction materials on lower floors and resulted in the amplification of microorganisms especially mesophilic and thermotolerant fungi. Concentrations of fungi in indoor air including Aspergillus, Penicillium and Paecilomyces approached or exceeded 104 colony forming units per cubic meter (cfu/m3). Airborne endotoxin levels increased about 1 order of magnitude over background levels. Sampling for fungi using both culture plate impactors and spore traps showed that spores were migrating from water damaged to undamaged areas in the office complex. Elevator shafts traversing water damaged floors likely provided the major dispersion pathway of spores into occupied areas. Construction materials such as plaster ceilings that had been wetted during the fire but were free of visual fungal contamination were found to be strong fungal reservoirs after the building had thoroughly dried. Management of microbial contaminants after a fire in a highrise building is an important public health concern and therefore an essential aspect of building restoration.
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  • 130
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Questionnaire reports on symptoms and sensations from 4943 office workers, measurements of indoor climate from 540 office rooms in 160 buildings, and measurements of TVOC in 85 rooms were used in an analysas of the role of indoor air humidity and the sensation of dryness as risk indicators of SBS (Sick Building Syndrome) symptoms. The sensation of dryness was strongly associated with the prevalence of SBS symptom reports. There were no associations between measured indoor air humidity and the prevalence of SBS symptoms or the sensation of dryness. A number of significant associations were demonstrated between the sensation of dryness and technical, air quality, psychosocial and personal variables. The frequency of reports of perceived “dry air” is an important indicator of the “sickness” of a building; indoor air humidity is not an indicator.
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  • 131
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 132
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: This paper investigates the conscious experience of thermal transients, both experimentally and by means of a model of dynamic thermoreception. The experiments involved a sample of twelve human subjects, each undergoing twelve different ambient temperature step-changes. The research design included both temperature up-steps and down-steps, clothed and naked subjects, and transients both away from, and towards, neutrality. Each experiment lasted three hours, with the step- change occurring after 1.5 h when the subjects crossed between the twin climate chambers. Immediate sensations resulting from the temperature up-steps closely resembled later steady-state responses to the warmer environment, while initial impressions of temperature down-steps were typically twice the magnitude of their up-step counterparts. These experimental findings were accurately simulated by a simple thermoreceptor model coupled to a numerical model of heat transfer through clothing and cutaneous tissue. This heightened subjective sensitivity to temperature down-steps was achieved with the model by taking the subcutaneous depth of cold thermoreceptors to be less than that of the warm units, as noted by Hensel in his review of this specialized field (1981).
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  • 133
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 134
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 135
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The prevalence of symptoms compatible with the Sick Building Syndrome (SBS) was measured in a questionnaire study among 4 943 office workers. An assessment of the relation between SBS symptoms and personal, physical and psychosocial exposure factors was made. In contrast to males, the majority of females were lower-grade staff Females reported annoyance from physical climate factors more often, both at work and at home. Males reported a better psychosocial situation than females. Female gender, asthmalrhinitis, paper and VDT work were related to an increased prevalence of SBS symptoms. The prevalence of facial skin symptoms increased markedly with the amount of VDT work. Psychosocial workload intensifid this relation. Inequalities in physical climate and psychosocial conditions associated with different positions held in the offices can be of importance for the increased occurrence of symptoms among females.
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  • 136
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Reactive indoor chemistry has seldom been considered in investigations of the health effects of exposure to indoor contaminants although improved understanding may help to reduce exposure misclassification as well as identify previously unknown exposures. Nitrous acid (HONO), formed from the heterogeneous reaction of NO2 with water on indoor surfaces, may be a neglected and important confounder in studies of nitrogen dioxide (NO2) health effects. The understanding of HONO – NO2 relationships is important since conventional measurements of NO2 actually measure a number of nitrogen oxides including HONO. Accordingly, we examined the effects of relative humidity, chamber residence time, the presence of carpeted sufaces and the presence of human subjects on the production of HONO following the injection of NO2 into a chamber. Increasing chamber relative humidity led to greater HONO concentrations at a given NO2 level. At 80% relative humidity, HONO concentrations were 11% of the NO2 concentration. Increased residence time in the chamber increased HONO levels, with a five-fold increase in HONO levels between 20 minute and 120 minute residence times. The presence of wool carpets in the chamber was not found to affect significantly the HONO production rates, although NO2 decay rates were increased. When human subjects were present in the chamber, HONO concentrations decreased by as much as 50% of the levels present under similar conditions with no subjects in the chamber. In light of our results we argue that future investigations of NO2 health effects and indoor air quality must recognize the importance of indoor chemistry, and in particular, the likelihood of elevated concentrations of HONO which will interfere with NO2 measurements and potentially confound the investigation of concentration-effect relationships. Similarly, previous studies demonstrating a relationship between health endpoints and NO2 exposure should be viewed with caution until the presence and importance of other potentially toxic nitrogenous compounds in the exposure environment are evaluated.
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  • 137
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Geological exploration has dentifid an unsuspected radon-prone belt in southern California. Detailed analysis of aeroradiometric (NARR) data, soil-gas radon, soil permeability, and finally indoor radon has identified the Rincon Shale and Rincon-derived soils in Santa Barbara County as anomalous in uranium and radon. Roughly 74% of houses on the Rincon Shale exceed 4 pCi/l and 26% exceed 20 pCi/l in standardized screening tests (3 to 7 day AC, “closed-house” lived-in rooms). Fifty three percent exceed 4 pCi/l in longer-term measurements (1 to 6 mo, AT) under normal ventilation conditions.Unusually strong correlations between aeroradiometric data, soil-gas radon adjusted for soil permeability, geology, and indoor radon reflect the unaltered character of sedimentary host rocks and a consequent tendency for anomalous uranium to occur throughout given rock units rather than in epzgenetic mineralized zones. Under these circumstances, deliberate geological exploration may be a more eficient approach to indoor radon risk identfication than simple random sampling or non-random testing of houses. By the same token, geological parameters can facilitate radon risk assessment on undeveloped lands. Attention is drawn to multiple populations within radon test samples and the consequent problems in estimating regional parameters.
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  • 138
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Some operators of climate installations still prefer the use of water humidifiers. Soaked surfaces and circulating water; together with impuritiesfiom the ventilation air, create a favourable environment for the growth of numerous microorganisms. Faulty operation of air-conditioners can constitute a risk to health. This has been proved many times in cases of certain hospital-acquired infections, a classic example being pneumonias caused by Legionella pneumophila. For this reason, the possibility of suppressing microbial contamination of circulating water in humidifis by using the oligodynamic potential of silver ions was investigated. Basic hygienic requirements were put fmard to ensure adequate quality of water in humidifis of air-conditioning installations.
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  • 139
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: This paper presents a series of fill-scale measurements of the concentration distribution in the centre plane of a room with isothermaI mixing ventilation.Vertical projiles of the concentration in the middle of the room have been measured under different conditions. With the contamination source in the middle of the room the vertical profiles were changed radically with an increase of the air change rate from n = 1.5h−1 to n = 6h−1 due to a change in the flow structure in the room. With a constant air change rate, the location of the contamination source in the room showed a great influence on the vertical profile. A high velocity around the contamination source resulted in a uniform contaminant distribution in the room, while a low velocity resulted in considerable differences.Contours of concentration in the centre plane of the room have been measured using different contaminant densities. The densities were low, neutral and high in relation to the density of air. The results showed that the contaminant distribution in the room with the chosen flow conditions depended strongly on the contaminant density, and that the high density case gave the highest concentrations in the occupied zone.
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  • 140
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 3 (1993), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: This paper presents the results of indoor radon surveys in the Sichuan province of China. The indoor radon concentrations found using scintillation or the two-filter method, ranged from 1.0 Bqm−3 to 170.2 Bqm−3. The arithmetic mean concentrations of indoor radon and its progeny were 17.8 Bqm−3 and 10.8 Bqm−3 EER (2.9 m WL), respectively. A seasonal pattern of the maximum in winter and the minimum in summer was observed for radon and its progeny concentrations. The annual effective dose equivalent resulting from indoor and outdoor inhalation of radon progeny totalled 0.93 mSv. Of the 109 million people living in Sichuan, 3000-6800 may die annually from lung cancer induced by the inhalation of radon progeny.
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  • 141
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study aimed to investigate the presence of microorganisms in the inner thread of the fixture (endosteal implant part) of the Brånemark™ system. In 9 volunteers the apical part of 2 abutment screws that had been in place for 3 months was examined by means of differential phase-contrast microscopy. All screws harboured a significant quantity of micro-organisms, mainly coccoid cells (86.2%) and nonmotile rods (12.3%). Motile organisms (1.3%) or spirochetes (0.1%) were only sporadically registered. A microbial leakage at the abutment/fixture interface probably is the most probable origin for this contamination.
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  • 142
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    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: An experiment was carried out to determine whether endosseous titanium implants (Brånemarks®) retain their clinical stability throughout a 26-week period of continuously applied force (2 N) and what kind of marginal peri-implant bone changes occur in the process. For this purpose 6 premolars (P3: mandible/maxilla and P4: mandible) were extracted from each of 2 foxhounds, and 12 implants (6 per dog) were positioned in the edentulous maxillary and mandibular areas after the alveolar healing period. Following a 25-week implant healing period, 8 fixtures (P3 areas) were used as anchoring elements for distalization of the 2nd premolars over a period of 26 weeks: 4 implants served as a control group (P4areas of the mandible). There were no clinical or histological signs of implant dislocation after the load application period. In the presence of mild peri-implant gingivitis, no increase was found in the incidence of marginal bone resorption adjacent to the loaded implants compared with the non-loaded implants. In the absence of marginal resorption, subperiosteal bone apposition was detected especially around the test implants in the mandible. This suggests that endosseous titanium implants are suitable as anchoring units for longer-term orthodontic tooth movements. The applied force may moreover induce marginal bone appositions adjacent I to the implants.
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  • 143
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Complete restoration of an osseous defect around a TiAl6V4(IMZ) implant is accomplished by the combined use of an implant placed in the alveolus of a fractured lower bicuspid and the principles of guided tissue regeneration. Gengiflex (Gengiflex - BioFill - Productos Biotecnologices, Curitiba, PR, Brazil), a new membrane, was used to cover the implant and porous hydroxyapatite was used as grafting material. The filling of the osseous defect that also covered the implant was verified clinically at re-entry 6 months later. Histological analysis of the mineralized tissue collected during exposure of the implant confirmed bone formation.
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  • 144
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Radiofrequent magnetron sputtering was used to produce calcium phosphate coatings on metal and plastic substrates. Scanning electron microscopy showed that the deposited films had a uniform thickness and a dense columnar structure. Energy-dispersive X-ray analysis, X-ray crystal diffraction and atomic absorption spectrometry demonstrated that the sputtered layer was well-crystallized calcium phosphate ceramic with a Ca/P ratio varying between 1.9 and 2.5. The biocompatibility of the coatings was determined by in vitro and in vivo experiments. It was found that the coatings were biocompatible without any sign of adverse tissue reaction. It was concluded that magnetron sputtering is a promising method for forming a biocompatible ceramic coating onto an implant material. Nevertheless, several problems have to be solved before magnetron sputtering can be used on a routine basis for the production of Ca/P coatings.
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  • 145
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Satisfactory functional and aesthetic rehabilitation of a patient after total bilateral maxillectomy is a great challenge to the surgeon and prosthodontist. A particular problem is support and retention of the obturator. In the case described, the problem was solved by attaching the prosthesis with finger clasps to a classic AO-reconstruction plate anchored rigidly with screws to both zygomata. The results in terms of mastication, swallowing, phonation and aesthetics were satisfactory for more than 2 years, when the patient died from brain metastasis and pneumonia. The technique seems promising and merits further study using titanium screws and plates.
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  • 146
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The study examines the effect of maxillary prosthetic appliances on the composition of the microflora in the peri-implant sulcus. Two groups of patients participated. One group consisted of 18 people with removable prostheses, and a second group of 9 people with fixed prostheses was chosen to match them in age. sex and function period of their prosthetic appliances. One implant site per patient was chosen for microbiological sampling, and the samples were taken on 2 separate occasions from all the subjects, with a 3-month interval. From those with removable prostheses, a further sample was collected by scraping a squared area from the mucosal side of the prosthesis. The prevalence of black-pigmented Porphyromonasl Prevotella. Actinohacllus actinomycetemcomitans, mutans streptococci, lactobacilli, enteric bacteria and yeasts was analysed using blood-agar and selective agar media. The results show that the prevalence was significantly higher for Lactohacillus, Prevotella spp. and yeasts in subjects with removable prostheses than in subjects with fixed prostheses. No significant difference was registered in the pattern of microbial composition in subjects with the removable prosthesis when the peri-implant sulcus plaque and the biofilm on the corresponding mucosal side of their prosthesis were examined. The insertion of a removable reconstruction to cover the area of the osseointegrated implants gave rise to a progressive change in the peri-implant plaque towards a-more aciduric micrdflora.
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  • 147
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The Scanora X-ray unit permits linear and rotational narrow beam radiography as well as spiral tomography, making it well suited for implant planning radiography. The purpose of this study was to evaluate the reliability of measurements made in spiral lower jaw tomograms of patients examined with the Scanora® technique. Six observers measured the distance between the alveolar crest and the mandibular canal in spiral tomographic images taken on 40 consecutive patients before implant surgery. In one randomly chosen image from each patient, the observers marked the measuring points at the two locations. The measurements were repeated 2 months later. Three of the observers, all radiologists. excluded in total 11 sets of images considered to improve if retaken. Analysis of variance showed an average standard deviation between observers of 1.67 mm. This was mainly due to the intraobserver variation, 1.07 mm. The variation between plots was significantly larger at the alveolar crest. Confidence intervals showed that reliability improves with multiple readings, either made independently by one observer or separately by several. The inter- and intraobserver variation decreased to 1.42 mm and 0.86 mm, respectively. without the images of inferior quality. Compared with a similar study based on hypocycloidal images, the variability was less due to the intraobserver variation and was affected positively by an optimized image quality.
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  • 148
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In order to satisfy the need to restore the aesthetics, phonetics and comfort and to facilitate optimal hygiene procedures, 20 edentulous patients were treated with a new concept of overdenture therapy on implants ad modum Brånemark. After 24±3.5 months the patients were re-examined. They were asked to answer a questionnaire and use a Visual Analogue Scale (VAS) to give their opinion on the prosthetic treatment. The results indicate that an implant-retained overdenture in the maxilla with this design can satisfy the patients needs in aesthetics, phonetics and comfort and can 1 facilitate oral hygiene measures.
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  • 149
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In guided tissue regeneration (GTR) procedures, flap recession or sloughing may occur as an unwanted sequel to the placement of a membrane. This study was designed to assess the applicability of laser Doppler flowmetry (LDF) in the evaluation of blood perfusion in the mucoperiosteal flap covering the membrane. Five Labrador dogs were initially used inthe study, but one animal was later excluded due to post-operative problems. Maxillary premolar teeth were extracted and full thickness mucoperiosteal flaps were raised. Following removal of the buccal bone plate, 4 titanium implants were placed on each side. An experimental biodegradable polylactic-acid membrane was placed over the fixtures on one side to allow for GTR. The mucoperiosteal flap was repositioned and secured with sutures. The contralateral side served as control with no membrane. Blood perfusion was measured in the flaps before surgery, immediately after suturing and at 24, 48 and 72 h postoperatively. A laser Doppler flowmeter was used to assess the blood perfusion. In 3 animals the membrane was exposed within 2 weeks post-operatively, and in these 3 animals the LDF values were lower on the membrane side than on the control side. The mean LDF value was lower on the membrane side for each of the 4 periods studied. The tindings suggest that LDF can be a valuable method to study blood perfusion of oral mucosal flaps and that there may be a relationship between a reduced relative LDF value and subsequent exposure of the membrane to the oral environment.
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  • 150
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The presence and distribution of intraepithelial antigen-presenting cells was studied in the keratinized mucosa around healthy osseointegrated implants and teeth. Vimentin, cytokeratins, HLA-Dr, CD18, ICAM-I and CDla-positive cells were assessed by a 3-stage ABC immunoperoxidase system in serial sections from clinically characterized sites. A total of 11 biopsies (7 adjacent to osseointegrated dental implants and 4 adjacent to teeth in healthy volunteers) were qualitatively and quantitatively analyzed. All biopsies displayed the presence of a small inflammatory infiltrate subjacent to themost coronal portion of the junctional epithelium. Intraepithelial antigen-presenting cell markers were present both around implants and teeth. The observations were consistent with the presence of functional local major histocompatibility complex Class II restricted antigen presentation. Quantitative differences were observed by analysis of variance in terms of different locations within the same section (i.e. junctional epithelium vs oral epithelium) and in terms of the source of the biopsy (i.e. implants vs teeth). The significance, if any, of the observed quantitative difference is discussed in terms of different maturity of the local immune response and possible environmental differences. It is concluded that clinically healthy keratinized mucosa around osseointegrated dental implants shares functional similarities with normal gingiva in terms ofantigen presentation. These results further contribute to the characterization of a functional local immune response that represents the basis for long-term clinical success of osseointegrated dental implants.
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  • 151
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Patients with resorbed edentulous upper jaws were arranged into 2 different groups, based on an overall assessment of bone resorption prior to implant surgery. Each group comprised 3.5 patients, all of whom received an overdenture after abutment connection. The patients in the group with the best bone situation were scheduled to receive a fixed prosthesis after 1 year provided that the clinical situation was stable. The overall cumulative implant and prosthesis treatment success rates were 77% and 85%, respectively, for a 3-year follow-up period. Nineteen of the patients in the best bone group received a fixed prosthesis after they had used the overdenture for 1 year. These patients exhibited a cumulative implant success rate of 97%. None of the fixed prostheses was lost. Implant failures and other clinical adjustments were frequent for the first year of follow-up, but the number of problems diminished in the subsequent years.
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  • 152
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim was to longitudinally follow the colonization of putative periodontal pathogens on titanium implants in partially edentulous patients. Nineteen individuals, who were partially edentulous and were on the waiting-list to be treated with titanium fixtures, were included in the study. They were treated for periodontal disease with oral hygiene instructions and supra- and subgingival debridement and were left for maintenance. Full-mouth recordings of each patient were performed at baseline, including attachment level and probing pocket depth. Bleeding was provoked and visible plaque were registered. Subgingival samples were taken for examination of Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans. Bridge connection was completed 1 month after abutment connection. The bone level was registered on radiographs. The patients were followed with clinical registrations and subgingival samples at 6, 12, 24 and 36 months. No significant changes in pocket depth, attachment level, bleeding on probing or plaque score occurred during the experimental period. The number of individuals positive at teeth and abutments for the various bacterial species reached approximately similar levels at 6 months. No significant changes over time were seen. Comparison between bone height. seen on radiographs, at abutments after 2, 12 and 36 months gave only 3 sites with bone loss of 〉 0.5 mm. All these sites were found in one patient and were accompanied by P. intermedia.
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  • 153
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this study was to investigate whether a new connective tissue attachment can occur on a surface of hydroxyapatite (HA) when peri-odontal ligament (PDL)-derived cells with the ability to form new connective tissue attachment are allowed to populate the surface of HA. Six maxillary canines from 3 cats were used for this experiment. Under anesthesia, fenestration of the buccal alveolar bone was performed over the canine root and a cavity was prepared on the root surface. A synthetic HA block was inlaid and cemented into the root cavity. A Teflon membrane was then placed to cover the access opening of the alveolar bone to guide PDL-derived cell proliferation into the surface of the HA block. Finally, the gingival tissue flap was replaced and sutured. Six months after the operation, histologic evaluation was done by serial sections. In 4 of the 6 canines, PDL-derived cells successfully populated the HA surfaces and a layer of cementum-like tissue was formed on the HA blocks. A PDL-like connective tissue layer was seen between the cementum-like layer covering the exposed HA surface and the newly formed alveolar bone sealing the bone fenestration. Collagen fibers in the PDL-like tissue inserted their ends into the newly formed bone and the cementum-like tissue. The present findings demonstrated that PDL-derived cells can 1 form a new connective tissue attachment on HA.
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  • 154
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to compare the effect of early versus late removal of expanded polytetrafluoroethylene (e-PTFE) membranes on bone formation at oral implants. Thirty Brånemark™ fixtures were placed into immediate extraction sockets with buccal bone dehiscences augmented by e-PTFE membranes. At 4 weeks, the membranes and underlying soft tissues were removed from 5 implants, but at 16 sites only the membranes were extirpated. In 9 sites, the membranes remained in place during the healing period. Sixteen weeks after fixture insertion, the sites in which the membrane was retained (MRET) showed an average of 5.2 mm of clinical bone height increase (lOO% of bone fill). For sites where the membrane together with underlying soft tissues were removed (MRB), the corresponding value was 2.0 mm (42% of bone fill. Implants at which only the membrane was removed (MR) showed the least clinical bone height increase (1.0 mm). resulting in 21% coverage of original threads. Histometric measurements verified that the MRET sites had the least distance from the top of the fixture to the newly formed bone level (0.4 mm). However, in contrast with the clinical findings, the histometric analyses showed that the MRB group had the greatest remaining bone defect (3.3 mm). The clinical and histometric results of the MRET group were statistically better, though, compared with those of the other two groups. Biopsies, removed from beneath the membranes, revealed slightly inflamed connective tissue, containing spicules of newly formed bone, indicating that more bone might have been created if the membranes had been retained longer. The current study thus showed that maximum bone formation around oral implants was created if the membrane augmentation material remained in place during the 16-week healing period. Early removal of membranes, with or without elimination of the underlying tissues resulted, however. in less newly formed bone and an incomplete defect bone fill.
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  • 155
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The surfaces of titanium (Ti) plates, as models for Ti implants, have been characterized by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF SIMS). Plates were prepared with rough and smooth surface topographies - the rough being similar to that of an implant. The XPS data has been used to construct a model of the plates' surface chemical structure, from the gas-solid interface through to pure Ti metal. At the surface of as-received plates, which underwent the same preparative procedure as an implant, considerable surface contamination was detected. In particular, high levels of carbon (C) contaminants were detected; the nature of this C was elucidated by fitting the C 1s core line and from the secondary ion mass spectra. The oxygen (0) 1s core line could not be fitted using a minimum of 2 gaussian peaks, demonstrating the multiplicity of 0 environments. The detection of other elements in the XPS analysis further demonstrated that, in nominally pure Ti plates, the surface chemical composition deviates considerably from that of the bulk. The data obtained from the plates were confirmed by examination of a Ti abutment. The handling of Ti plates with stainless steel tweezers was investigated. No obvious change in surface chemistry was detected. All the above results bring into serious questions the validity of rigorous protocols demanded, in some techniques, in the 1 handling and use of Ti implants.
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  • 156
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this study was to evaluate the marginal tissue response adjacent to implant supported overdentures. Twenty edentulous patients had 2 Astra Dental Implants® placed in the canine region of the lower jaw. New overdentures were retained by individual ball attachments in 11 patients and by a bar attachment in 9 patients. Periodontal registrations were recorded 0 months, 6 months, 12 months and 24 months after the overdentures were inserted. One of the 40 fixtures was lost at the stage of abutment connection. No fixtures were lost during the 2- to 4-year observation period and no fixtures showed any periodontal signs of failure. At the 2-year examination, no pocket depths adjacent to the implants exceeded 4 mm and no bone loss exceeded 3 mm. The mean annual bone loss was less than 0.2 mm during the first 2 years. The preliminary results from this limited study were promising and showed that two osseointegrated Astra Dental Implants® could successfully retain an overdenture in the lower jaw. However, long-term observation is needed for a definate evaluation of this treatment concept.
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  • 157
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to compare the effect of plaque accumulation in conjunction with or without placement of plaque-retaining ligatures on peri-implant and periodontal tissues. Four cynomolgus monkeys received 2 ITI (Type F) dental implants in edentulous areas of each side of the mandible. Following a healing period of 2 months with regular prophylaxis procedures twice per week, plaque was allowed to accumulate. After 1 month (day 0), silk ligatures were placed around 1 of the 2 implants. The third molars served as controls and were ligated as well. Clinical examinations comprising Plaque Index (PlI), Gingival Index (GI), probing depth (PD) and loss of attachment (LA) were performed at the test and control sites before and 1, 2, 3, 4, 5, 6, 7 and 8 months after ligature placement. Sixty and 30 days prior to ligation and at 2, 5, 6 and 8 months following ligation, standardized radiographs were obtained and subtracted from a baseline radiograph obtained at the time of ligation. PI1 and GI scores increased significantly following the elimination of prophylaxis procedures. After ligation, these indices continued to increase and reached values significantly higher in ligated implant (LI) and ligated teeth (LT) sites than in non-ligated teeth (NLI) sites. PD also increased after plaque accumulation and ligature placement. Significantly greater PD values were noted in LI and LT sites than in NLI sites. Also, loss of attachment was observed already after 1 month following ligation in LI and LT sites and reached a value of 3.8 mm after 8 months, whereas only 1.0 mm of attachment was lost after 7 months of plaque accumulation in NLI. Similar results were noted in the analysis of the subtraction images. LI and LT sites lost significantly more bone density and more alveolar bone height, but the NLI sites yielded relatively stable conditions throughout the study. It is concluded that the development of a peri-implant infection progressed at a similar rate as the development of a periodontitis lesion and that ligature placement significantly promoted the development of these lesions when compared with the development of an inflammatory response in the peri-implant tissues as a result of bacterial plaque accumulation.
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  • 158
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A radiologic evaluation of marginal bone loss around single implants ad modum Brånemark and their adjacent teeth was performed: 58 adults with 71 fixtures were followed up to 3 years after crown installation. The following factors were considered: age, cause of tooth loss, vertical relation between fixture and teeth, distance between adjacent teeth, distance between fixture and natural tooth, jaw region. Specified distance were measured as well as marginal bone levels around fixtures and tooth surfaces in magnified standardized intraoral radiographs. The results show a loss of marginal bone support at tooth surfaces adjacent to inserted implants during the interval between preoperative examination and crown installation that exceeds the loss during subsequent years. The largest bone loss was observed when implants were placed next to lateral upper incisors. A strong correlation was found between bone loss at adjacent teeth and the horizontal distance fixture-tooth. With decreasing distance the bone loss increased, especially in the upper incisor region. At present it seems difficult to predict which individual or individual condition may have a higher risk for bone loss, due to large intra- and 1 interindividual variation.
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  • 159
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In this investigation, the tissue reactions towards titanium implants inserted in growing jaws of pigs were studied by means of histology. At the age of 12 weeks, 5 test pigs each received 4 Brånemark System* titanium implants (fixtures). The fixtures were inserted immediately after extraction of the mesial root of the second deciduous premolar (P2) and the deciduous canine (C) on one side of the mandible and the mesial root of the first deciduous premolar (PI) on the other side. The fourth implant was placed after extraction of the deciduous lateral incisor (L) on one side in the upper jaw. Furthermore, 1 pig in which no extractions or fixture installations were performed served as a control. All pigs were followed for 165 days with clinical, radiographic and biometric examinations, the results of which have been previously presented. In this study, 10-μm-thick ground sections were produced for histology after the jaws had been fixed by immersion in formalin and further processed and embedded in plastic resin. Six of the fixtures originally inserted were lost during the experimental period, and the remaining implants were found to be involved with mineralized bone to varying degrees. Regarding the fixture-to-teeth relationship, it was found that, in the premolar region of the lower jaw, the teeth were positioned superior to and buccally angulated in relation to the fixtures. In the upper jaw, the implants were positioned below the adjacent teeth but centrally in the alveolar process. Tooth germs adjacent to the fixture had a displaced eruption path, buccally or lingually to the fixture. If the bud developed in close contact with the fixture, a changed morphology of the germ could be observed.
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  • 160
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Strain gauges were used to record in viva and in vitro functional deformations in a fixed prosthetic appliance supported and retained by osseointegrated titanium implants. Four linear gauges were attached to each of totally 5 implant abutment cylinders and gauge signals were transferred into a computer via a digital converter. A computer program (ASYST) was used for collection, calibration and analysis of data obtained. Based on the results of a series of explorative in vitro tests, in viva experiments were performed at maximum biting as well as during chewing on certain normally available food items. The results show fundamental differences between in vitro and in vivo testing conditions. Unexpectedly high bending of the implants was recorded in many of the in viva loading situations.
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  • 161
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The cleaning effectiveness of different treatment methods for titanium abutments was evaluated using scanning electron microscopy (SEM). In the mandible of 4 beagle dogs, 25 titanium abutments were installed (modum Brånemark). After 16 weeks of plaque accumulation, mineralized deposits had formed on 23 abutments. Each of these abutments was subjected to one of the following treatment methods: scaling with (1) metal, (2) plastic, or (3) ultrasonic instruments;(4) air-polishing, (5) weekly rubber cup polishing or (6) daily brushing with a conventional toothbrush. Fourteen abutments were removed immediately after treatment. On 9 abutments, the scaling procedures and air-polishing were repeated after another 16 weeks of plaque accumulation. The abutments were prepared for SEM, and each of them was viewed and photographed at 3 different magnifications. The photomicrographs were evaluated by 3 examiners who, guided by reference pictures, gave each abutment a “cleanliness” score, ranking from 0 to 5. Regular rubber cup polishing and regular brushing resulted in the highest surface cleanliness, while the air-polishing procedure showed the lowest cleanliness score. None of the 3 scaling methods created a cleanliness score better than 3. The 3 scaling methods were considered equal in their cleaning effectiveness. No differences could be observed between surfaces treated 1 x or 2 x Taken the present findings and those of other studies concerning the effects of scaling on the surface roughness and biocompatibility into consideration, it was concluded that plastic scalers may be the instruments of choice for debridement of titanium implant surfaces.
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  • 162
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Speech may be affected by the transition from complete dentures to fixed prosthesis on osseointegrated implants (OIB). If so, is there any correlation between interdental spaces (open or closed) in the prosthodontic construction and deteriorated speech? 21 individuals advocated for maxillary OIB were randomised so that one half of the group got constructions with wide interdental spaces and the other half with minimised inter-dental spaces. All patients were examined audiologically and their speech was individually tape-recorded before and after treatment. Perceptual, acoustic, model and audiological analyses were made. Approximately 60% of the patients were judged to have indistinct speech after the treatment. The s-sound was perceptually and acoustically distorted. 67% of the patients suffered from hearing defects. No correlation between interdental spaces (open or closed) and deteriorated speech could be found. It is supposed, that hearing plays a part in the effort to adjust speech to a new maxillary OIB, and thus reduced hearing can enhance speech difficulties.
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  • 163
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The installment of endosseous dental implants has become an accepted treatment procedure, and the long-term clinical results appear excellent. The composition of the soft tissue environment, however, is different from that around natural teeth. One characteristic of original junctional epithelium is its association with plasminogen activator (PA) activity. In 11 patients with a total of 30 IT1 hollow-screw titanium dental implants, 16 biopsies were taken. Histologic cryostat sections were assayed for the presence of PA in the junctional epithelium. The results demonstrated that junctional epithelium around titanium implants yields PA activity in a manner very similar to that of natural teeth. The ability to produce this enzyme activity is not related to the developmental origin of the junctional cells, but to their position and function at the base of the gingival sulcus.
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  • 164
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The microflora around titanium implants and teeth in 4 beagle dogs was analyzed in order to follow the longitudinal development from healthy conditions to experimental gingivitis and periodontitis. A 2-month plaque control program was performed to establish healthy conditions on titanium implants and control teeth (baseline, day 0). Subgingival bacterial samples and radiographs were obtained. The plaque control was ceased and all measurements were repeated on day 21 (gingivitis). A new period of plaque control was initiated to re-establish healthy conditions (day 49). A cotton ligature was placed subgingivally around the implants and the control teeth to induce tissue breakdown. The ligatures were removed on day 91. The study was completed with registrations on day 121 (periodontitis). No significant microbiological difference was found between titanium implants and teeth in healthy conditions and in gingivitis and periodontitis. The mean total viable count increased 10 times on implants as well as on teeth. Streptococci were dominating at baseline: 40.2% on implants and 60.6% on teeth and decreased in gingivitis to 11.7% and 5.4%. When periodontitis had developed, the proportion of streptococci was 〈 1%. At baseline few Porphyromonas gingivalis and Prevotella intermedia were detected. They increased at gingivitis to 37.4% and 21.0%; when periodontitis developed, they comprised about 25.0%. Microbial colonization and establishment on titanium implants with healthy gingiva, experimental gingivitis and periodontitis follow the same pattern as on teeth.
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  • 165
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: An intimate contact between bone and titanium implants was first demonstrated in 1969. and since then the bone-implant interface of osseointegrated implants has been investigated extensively. However. investigations of the marginal tissues and the microflora associated with osseointegrated implants have almost exclusively been carried out over the last decade. This review covers the clinical, radiographic, histologic, and microbiologic studies of marginal tissues of osseointegrated oral implants. In general, successfully osseointegrated implants exhibit low amounts of plaque con-comitant with the absence of marginal inflammation. However, plaque accumulation may cause inflammatory reactions around the implants, sometimes giving rise to mucosal hyperplasia. Apparently, keratinized mucosa is not a requisite for the maintenance of peri-implant health if oral hygiene is adequate, but the presence of peri-implant keratinized mucosa is generally advocated. Alveolar bone loss around successful implants is minimal, but significant focal loss may occur due to plaque-induced inflammation or perhaps repeatedly extensive implant load. The progression of plaque-induced alveolar bone loss of osseointegrated implants may be different from that of teeth. It is unknown whether simultaneous marginal inflammation and excessive implant load further increase the loss of alveolar bone height. Both the light microscopic and ultrastructural characteristics of marginal tissues of implants and teeth are similar except for a lack of root cementum with inserting gingival collagen fibers of implants. Clinical inflammatory reactions are histologically characterized by an increased number of inflammatory cells infiltrating the connective tissue. The scattered subgingival microbiota associated with osseointegrated implants surrounded by healthy or slightly inflamed marginal tissues is similar to that of teeth with healthy gingiva. The microbiota associated with implants affected by marginal inflammation and bone loss is complex and consists predominantly of gram-negative anaerobic rods: this. again, is a similarity to periodontal disease.
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  • 166
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Eight non-submerged titanium implant screws were placed in the first upper molar edentulous sites of monkeys and subsequently kept loaded with single crown prosthesis 1 month following implantation. The animals were killed after a further 14 months and specimens including implant and adjacent teeth were processed for light and electron microscopy. Histological pictures of all samples showed the neck and most of the screw body to be surrounded by new bone. The soft tissue surrounding the implant post included pocket epithelium and supra-crestal connective tissue displaying collagen fiber bundles comparable to gingival ligaments. These peri-implant collagen fiber bundles arose from the neighboring alveolar crest, root cementum of adjacent teeth or, superficially, from the epithelium and followed a circular array around the implant neck.
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  • 167
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to investigate the possibility of antimicrobial treatment of peri-implant infections associated with a periodontitis-like subgingival microbiota. Nine partially or fully edentulous patients with titanium hollow cylinder implants were selected which showed loss of bone and probing depths ≥ 5 mm on one or several implants after at least 6 months following installation. They also yielded subgingival microbial samples with ≥ 106 CFU/ml, including ≥ 20% gram-negative anaerobic bacteria, The treatment included mechanical cleaning, irrigation of all peri-implant pockets 〉 3 mm with 0.5% chlorhexidine and systemic antimicrobial therapy (1000 mg ornidazole for 10 consecutive days). After therapy, bleeding scores decreased immediately and, over a one-year observation period, remained significantly lower than before treatment. A significant gradual reduction in mean probing depths was detected over this one-year period; only one case showed no improvement of local probing depth. Microbiological parameters indicated an instantaneous quantitative and qualitative change following treatment. Subsequently, several of these parameters tended to shift back towards pre-treatment values. In the second half of the observation period, however. this tendency was reversed, and levels significantly different from baseline were eventually established. This study demonstrated that treatment aiming at reducing the subgingival bacterial mass and suppressing the anaerobic segment had a beneficial effect in patients suffering from peri-implantitis.
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  • 168
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Several parameters have been described to determine success or failure in long-term evaluations of dental implants. One of these parameters is the observation of changes in peri-implant bone levels. Studies on submerged implants have analyzed the bone level changes in the pre- and post-loading phases. No such data exist for intentionally nonsubmerged implants. The purposes of this study were: (1) to test the applicability and reproducibillity of a simple computer-assisted method in the evaluation of changes in peri-implant bone levels;(2) to establish a baseline for the longterm radiographic follow-up; and (3) to evaluate changes in crestal bone levels adjacent to nonsubmerged IT1 implants between the 1-year and 2-year examination. Standardized periapical radiographs were obtained from 80 implants at the l-year and 2-year follow-up examinations after their placement. The implants were located in different jaw areas of 55 patients and supported single crowns or short-span fixed partial dentures. For each implant, the distance from implant shoulder to first crestal bone contact (DIB) was measured at the proximal surfaces with a digitizer/computer assembly. Statistically significant greater mean DIB were found at the l-year (baseline) evaluation for: (I) maxillary sites overall (4.10 x 1.02 mm (SD)) compared with mandibular sites overall (3.61 ± 1.03 mm);(2) maxillary anterior sites (4.08 ± 0.97 mm) compared with mandibular posterior sites (3.60 ± 1.05 mm); and (3) maxillary posterior sites (4.13 ± 1.12 mm) compared with mandibular posterior sites. No statistically significant changes in DIB occurred in any of the jaw locations between the l-year and 2-year evaluations. These results indicate similar changes in peri-implant bone levels for non-submerged implants over a 2-year period 1 as reported for submerged fixtures.
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  • 169
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this research was to determine the nature of the residual hydroxyapatite (HA)-coated implant surface after treatment with various chemotherapeutic modalities, including: citric acid, chlorhexidine gluconate, hydrogen peroxide, tetracycline HCl, stannous fluoride, polymyxin B and a prototype plastic Cavitron tip. Implant surfaces were evaluated macroscopically, microscopically (scanning electron microscopy (SEM)) and spectrometrically (energy-dispersive spectrometry and X-ray diffraction). HA-substrate bond strength and dissolution testing was also performed for surfaces treated with a supersaturated citric acid solution. All treatments left either microscopic residues or a loss of surface roughness when viewed on SEM. A 30- to 60-s application of citric acid left a significantly greater coating thickness than all other treatments, whereas a 3-min application of citric acid removed significantly more HA than untreated controls. Significant changes in CaiP ratios were seen with most treatments. The clinical significance of this phenomenon is not known. No treatments altered the crystallinity of the residual HA coating. A l-min application of citric acid did not significantly alter the tensile bond strength of the coating to the substrate. The clinical significance of these findings is not known at present. However. when taken with results from previous studies. it appears that in treating the infected HA-coated implant surface, a 30- to 60-s application of citric acid (pH 1) may be beneficial in detoxifying the HA coating prior to regenerative procedures. Further in vitvo and in viva studies are necessary to evaluate the biological response to citric acid when used to detoxify the infected implant surface.
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  • 170
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The experiment was performed to evaluate the effects of long-standing plaque on the gingiva and peri-implant mucosa. 5 beagle dogs were used in the study. The mandibular right premolars were extracted. 3 months later, 3 titanium fixtures were installed and after another 3 months, abutment connection was performed. Plaque control, in the implant as well as the contralateral tooth regions, was maintained during a 4-month period prior to the start of the main experiment. On Day 0, the teeth and implant sections were examined with respect to plaque and gingivitis. The plaque control program was terminated. The animals were subsequently fed a diet which allowed gross plaque accumulation. After 90 days of undisturbed plaque formation, the dogs were re-examined and biopsies harvested from implants and contralateral teeth. On day 90, all teeth and implants had accumulated large amounts of plaque. The soft tissue at implants and teeth bled on gentle probing. The histological examination of the gingiva and the peri-implant mucosa revealed:(i) both tissues contained an inflammatory cell infiltrate; ICT, (ii) the apical extension of ICT was more pronounced in the peri-implant mucosa than in the gingiva and (iii) the composition of the 2 lesions had many features in common.
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  • 171
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It has been documented that the long-term clinical outcome of the Brånemark® system is very favourable. However, failures do occur before and after loading. This study examined the differences in marginal bone loss between standard and self-tapping fixtures and attempted to explain excessive marginal bone loss or loss of osseointegration during the first 3 years of loading. Marginal bone loss (scored on long cone radiographs) and fixture failure rate were compared for different fixture designs. For standard fixtures, in comparison with self-tapping fixtures, the failure rate was clearly higher before as well as after loading. However, for successful fixtures no difference in marginal bone loss was observed. For the conical fixtures an increased marginal bone loss around the smooth part was observed. The effect of fixture overload, marginal bone height and loss of osseointegration was examined in 69 patients with 1 and 15 patients with 2 fixed full prostheses, and in 9 patients with an overdenture in the upper jaw. Excessive marginal bone loss (more than 1 mm) after the first year of loading and/or fixture loss correlated well with the presence of overload due to a lack of anterior contact. the presence of parafunctional activity and osseointegrated full fixed prostheses in both jaws.
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