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  • Wiley-Blackwell  (123,377)
  • Munksgaard International Publishers  (320)
  • 1990-1994  (66,389)
  • 1970-1974  (30,761)
  • 1965-1969  (26,547)
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  • 1
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This investigation was performed to assess the bone-to-implant surface contact at fixtures of titanium that either had a standard machine prepared or a TiO2-blasted surface. Five beagle dogs were used in the experiment. Extractions of the premolars were performed in the maxilla. After 4 months of healing, 5 standard machine-prepared fixtures and 5 prepared according to the TioBlast technique were inserted. Two months later another 5 “standard” and 5 TiO Blast-prepared implants were inserted. Four months after the first fixture installation, the animals were killed and ground sections prepared from each implant site. Of the 20 implants installed, 19 were successfully incorporated. The mean bone-to-implant surface for “standard” fixtures was about 40% both at the 2 and 4 months observation interval. The corresponding figures for the TiO Blast-prepared fixtures were similar during the first 2 months of observation, while subsequently the TioBlast-prepared fixture surface seemed to stimulate to a more close bone-to-implant contact (65%) than the “standard” one.
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  • 2
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A photogrammetric technique was tested to measure the topography of the mucosa around implants, placed in edentulous upper jaws. Photographs were taken of casts from 6 patients, who all had used a removable overdenture for one year. Another series of photographs was taken on new casts after the use of a fixed prosthesis for a second year. The 6 pairs of photographs were measured and compared in an analytical stereo plotter for surface contour and implant positions. The results from the measurements indicated a trend of general recession of the mucosa after one year with fixed prosthesis. both on the buccal as well as on the palatal side. The mean volume of recession was 222.4 mm3, corresponding to an average of 0.4 mm3/mm2 of mucosa. More recession was generally observed on the palatal side, but obvious variations between the patients were present. In conclusion, the photogrammetric technique was considered to be well suited for analysing tissue contours in various dental situations.
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  • 3
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this study was to explore the possibility of creating bone tuberosities on the mandibular ramus in rats, using a rigid, occlusive. Teflon capsule. The experiment was carried out in 30 rats. The mandibular ramus was exposed bilaterally. On the test side, the periosteum was left covering the lateral surface of the ramus. On the contralateral side (control). the periosteum was elevated from the lateral surface together with the flap. A hemispherical, Teflon capsule was then placed to face the periosteum or the bone surface with its open part before closure of the wound. The healing periods comprised 7–120 days. Histological analysis demonstrated increasing bone fill in the test specimens from 7 to 60 days, and a limited further increase was observed from 60 to 120 days. In the control specimens, limited bone fill was seen within the first month after surgery, but substantial amounts of new bone were produced from 30–120 days. At 120 days, the mean amount of bone obtained in the test specimens was 56%(range 39%-71%) of the total space created by the capsules, and it was 52%(range 32%-85%) in the controls. The amount of newly formed bone was equivalent to a 5–6 times increase of the original width of the mandibular ramus. These findings indicate that a secluded space created by an occlusive barrier adjacent to existing bone or periosteum may be filled out with bone tissue. This may have a great clinical impact in cranial and maxillofacial surgery.
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  • 4
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Seventy-six patients were consecutively treated with fixed prostheses supported by osseointegrated implants in the edentulous maxilla and followed up for 5 years. The mean bone quality and resorption indices were 3.1 and 2.7 at the time of implant placement, respectively. Altogether, 449 standard Brånemark implants were placed. Two patients resumed to complete dentures, and the cumulative implant and prosthesis survival rates were 92.1% and 95.9% for 5 years, respectively. The mean marginal bone level was 0.6 mm below the reference point at the time of placement and 1.2 mm below the same point 5 years later. Speech problems was the most frequent complaint during the first year of function, while resin fractures caused most adjustments during the follow-up period. No implant, abutment or gold alloy screws were found to be fractured, and only 4 patients had their prostheses re-tightened due to loose gold alloy screws.
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  • 5
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: There is increasing interest in how pathways of tissue destruction around dental implants are similar as for teeth and how these pathways can be modulated to slow loss of supporting bone. The purposes of this study were to develop a short-term animal model to study the effect of the nonsteroidal anti-inflammatory drug flurbiprofen, on slowing the rate of induced peri-implant bone resorption. A total of 20 cylindrical titanium implants were placed in 2 beagle dogs using a low-trauma surgical technique. During the 3-month healing period without functional loading of the implants, daily oral hygiene was performed to maintain a Gingival Index of 0 to 0.5. At completion of the healing period, a baseline evaluation was performed which included the uptake of the bone-seeking radiopharmaceutical (BSRU)99mtechnetium-tin-diphosphonate (99mTc-Sn-MDP) in peri-implant bone and standardized radiographs. Peri-implantitis was induced with 4-O silk ligatures, cessation of oral hygiene and soft diet. One beagle was given 0.02 mgikg of flurbiprofen by mouth; the other received a placebo. BSRU and radiographic height of bone were remeasured to calculate the rate of bone loss during the 60-day treatment period. The percent rate of bone loss during the study period was calculated from the radiographs using a computer-assisted method. The radiopharmaceutical uptake for the flurbiprofen-treated implants remained unchanged. However, BSRU for placebo-treated implants was significantly increased from baseline. Radiographic measurements of bone height revealed that the mean rate of bone loss around implants in the flurbiprofen-treated dog (0.066±0.351%/month) was significantly lower than the rate around implants in the placebo-treated dogs (5.729±0.384%/month) over the 60-day treatment period. These data indicate that peri-implant bone loss can be rapidly induced and measured in the beagle and that flurbiprofen. administered orally, can significantly decrease the rate of induced peri-implant bone loss.
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  • 6
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This report presents 4 cases with 6 implant exposures after the installation of Bråemark System® implants which called for treatment applying the guided bone regeneration technique. A bioresorbable barrier (GUIDOR® Matrix Barrier) was used to cover the defects, 4 defects with and 2 without the support of autologous bone chips. Complete bone filling was found in 4 (2 without and 2 with bone chips) and partial filling in 2 (with bone chips) of the treated defects, as registered at the abutment connection 6–7 months after surgery. Besides its ability to serve as a barrier for guided bone regeneration, it was found that the matrix barrier had the following properties; biocompatibility observed as uneventful tissue healing, malleability facilitating the clinical handling and ability to be resorbed within 6 to 7 months, as evaluated by clinical inspection. The observations of the present case reports indicate that the tested barrier may be used for guided bone regeneration in connection with implant installation. It is advisable, however, to use a supporting material to prevent barrier collapse, although bone regeneration can be achieved in certain situations without such material if the defect morphology is favourable.
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  • 7
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study details the structural and ultrastructural features of the interfaces between titanium implants and their surrounding tissues. The material stemmed from an experiment in dogs in which guided tissue regeneration with Gore-Text membranes was used to treat peri-implant, ligature-induced tissue breakdown around submerged and nonsubmerged com-mercially pure titanium implants. Specimens from the nonsubmerged group were evaluated under light microscopy and scanning and transmission electron microscopy. A healthy gingiva and a gingival sulcus were formed around the implant necks. A regenerated junctional epithelium provided the epithelial union between implant and gingiva. The supracrestal connective tissue was characterized by a 3-dimensional network of collagen fibers, fibroblasts and blood vessels. Near the implant surface the collagen fibers ran parallel to the titanium surface or were orientated perpendicular to the implant. The connective tissue-implant interface was characterized by a fine fibrillar material interposed between the implant surface and the connective tissue. An unidentified material was also observed between the endings of functionally orientated collagen fibrils and the metallic surface. The apical portions of the implants were anchored in compact bone. At the bone-implant interface, either mineralized bone matrix was intimately adapted to the titanium surface without any intervening space or a 0.5 μm wide unmineralized layer was interposed. These findings indicate that a perimucosal seal was formed around the implants consisting of a junctional epithelium-implant union coronally and supported by the connective tissue-implant junction apically. The implants were integrated in connective tissue, but only tightly adapted to bone.
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  • 8
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The principle of guided tissue regeneration has been successfully applied for the regeneration of bone in various jaw defects in human. The purpose of this study was to assess the bone volume regenerated using nonresorbable membrane barriers. Nineteen patients with jaw bone defects of various sizes and configurations were included in the study. Combined split-thickness/full-thickness mucosal flaps were elevated in the area of missing bone. The size of the defects was assessed by measuring the distance from a reference line between 2 adjacent teeth (cementoenamel junctions) to the alveolar crest (a) every 2 or 3 mm. In addition, the crestal width was measured. Consequently, the surface of the triangle formed by a and the width of the crest as well as the volume between all triangles were calculated geometrically. Following the placement of Gore-Tex® augmentation material as a barrier, the distance (b) to the top of the membrane from the reference line was assessed, and the maximum possible volume for bone regeneration based on (a-b) and the width of the crest was calculated. At the time of membrane removal (3–8 months later). the same measurements were performed and the percentages of regenerated bone in relation to the possible volume for regeneration determined. In 6 patients in whom the membranes had to be removed early due to an increased risk for infection between 3 and 5 months, bone regeneration varied between 0 and 60%. In 13 patients in whom membranes were left for 6–8 months, regenerated bone filled 90–100% of the possible volume. It was concluded that successful bone regeneration consistently occurred with an undisturbed healing period of at least 6 months.
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  • 9
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A photogrammetric technique was designed to measure the position of dental implants in 3 dimensions to enable assessment of the tit of superstructures placed on the implants. A relatively simple camera setup was developed and tested. Calibration of the camera was performed in a high-precision analytical plotter and revealed a film measurement accuracy of 0.005 mm. The achieved measuring accuracy for clear and well defined points on clinical components was found to be around 0.02 mm. To find the center points of the implants, points on the circumference were measured. These points are not well defined, which resulted in an estimation of the center point of the implant with a precision of 0.05 mm. Independent measurements of a prosthesis with 5 implants were also within the precision of 0.05 mm. The angular orientation of the top surface of the implant cylinder (abutment, brass replica of gold alloy cylinder of the framework) was measured with a precision of 0.01 radians, which corresponded to an error with a peripheral gap of about 0.03 mm. This value was about 5-10 times lower than the clinical fit between frameworks and abutments, measured in 3 randomly selected clinical cases.
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  • 10
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Background. In the Danish Town Hall Study" it has previously been shown that the sick building syndrome is a widespread phenomenon. This has given rise to speculations as to whether biologically active components in dust or whether absorbed organic gases and vapours in the indoor climate may be partly responsible for the sick building syndrome. Therefore, we wished to study whether qualitative conditions in dust, of a physical, chemical, and biological nature, are related to the prevalence of symptoms of the sick building syndrome. Material and methods. The study included 12 town halls in the Copenhagen area. A total of 870 persons participated, 584 women and 286 men. All the participants filled out a questionnaire regarding health and working conditions, and dust samples were collected with a special vacuum cleaner in the working environment of the participants, after which the contents of inorganic and organic particles as well as of human source fragments the (hair, nails, skin) and various fibres were determined. Results. There was a significant correlation (P〈0.05) between the prevalence of gram-negative bacteria in the indoor climate dust, and general symptoms (fatigue, heavy-headedness, headache, dizziness, concentration problems) (corr.coeff.=0.73), as well as symptoms from the mucous membranes of the upper respiratory tract (corr.coeff.=0.76). Also, there was a significant relation between the prevalence of particles in the dust and the prevalence of symptoms from the mucous membranes (corr.coeff.=0.81). There was a strong and significant correlation between the total amount of volatile organic components (TVOC) and lack of concentration (corr.coeff. =0.85) and feeling heavy-headed (corr.coeff.=0.72). Macromolecular dust (potentially allergenetic material) was significantly correlated to the prevalence of headache and general malaise/dizziness (corr.coeff.=0.66), while the ability of the dust to liberate histamine was significantly related to the prevalence of general malaise, dizziness (corr.coeff.=0.65) and lack of concentration (corr.coeff. =0.58). Further analyses including a number of potential confounders did not change the results of the above analyses. Conclusion. The results of this study support the hypothesis that qualitative properties of dust are important to the sick building syndrome. The study was based on relatively few buildings, but nevertheless strong correlations were found. In perspective, epidemiological intervention studies should be carried out to investigate whether minimizing the amount of both dust and bacteria in the indoor climate affect the prevalence of sick building syndrome.
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  • 11
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 12
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 13
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: We tested nasal detection thresholds for airborne chemicals in a group of anosmics (i.e., subjects lacking a functional sense of smell) and in a group of age-, gender-, and smoking-status-matched normosmics (i.e., subjects with normal olfaction). Anosmics provided odor unbiased nasal pungency (irritation) thresholds. Normosmics provided odor thresholds. Homologous series of alcohols, acetates, and ketones served as stimuli. Eye irritation thresholds were also measured for selected acetates. Most substances evoked pungency (i.e., were detected by the anosmics). All sensory thresholds decreased systematically with carbon chain length. The gap between pungency and odor grew larger with increasing carbon chain length. Pungency thresholds-but not odor thresholds-showed a uniform linear relationship of slope close to unity with saturated vapor concentration, irrespective of chemical functionality or carbon chain length. This suggests that pungency from nonreactive airborne chemicals rests heavily on a relatively unspecific physical interaction with a susceptible biophase. Of relevance to indoor environments, such an interaction opens the possibility for a high degree of sensory addition of pungency from individual components of complex mixtures resulting in noticeable irritation even when each component is at a level well below threshold value.
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  • 14
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The filtration efficiency of ventilation air cleaners is highly particle-size dependent over the 0.01 to 3 μm diameter size range. Current standardized test methods, which determine only overall efficiencies for ambient aerosol or other test aerosols, provide data of limited utility. Because particles in this range are respirable and can remain airborne for prolonged time periods, measurement of air cleaner fractional efficiency is required for application to indoor air quality issues. The objectives of this work have been to 1) develop a test apparatus and procedure to quantify the fractional filtration efficiency of air cleaners over the 0.01 to 3 μm diameter size range and 2) quantify the fractional efficiency of several induct air cleaners typical of those used in residential and office ventilation systems.Results show that efficiency is highly dependent on particle size, flow rate, and dust load present on the air cleaner. A minimum in efficiency was often observed in the 0.1 to 0.5 μm diameter size range. The presence of a dust load frequently increased an air cleaner's efficiency; however, some air cleaners showed little change or a decrease in efficiency with dust loading. The common furnace filter had fractional efficiency values of less than 10% over much of the measurement size range.
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  • 15
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The indoor concentrations of contaminants originating from outdoor sources have been measured and calculated under transient conditions. The results show that contaminants that are supplied to an office building via the ventilation system can reach considerably high concentration levels. The indoor/outdoor concentration ratio and time lag are dependent on the air change rate. In buildings with low air change rates the indoor concentration variations are smoothed out compared to buildings with high air change rates. The results from the theoretical model are compared to the results from both laboratory and field measurements and the model is verified for well mixed conditions in a 20 m3 test chamber. The model can be used to simulate different control strategies for reduction of indoor contaminant concentrations related to outdoor sources. One such control strategy is based on reduction of the outdoor air change rate during periods with peak outdoor contaminant concentrations.
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  • 16
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: To test the reproducibility of a questionnaire previously used to study the association between respiratory symptoms and home dampness/mold, it was sent to the parents of 1,596 children twice, with an interval of one month between distributions. A total of 770 respondents completed the questionnaire both times and were entered into an analysis. For exposure variables, percentages of agreement between the two administrations ranged from 87% for visible mold growth in the home to 95% for basement flooding. Respective kappa scores ranged from 73% to 82%. Percentage agreements for the adults' symptoms variables ranged from 80% for upper respiratory symptoms, to 99% for physician-diagnosed asthma. Percentage agreements for children's symptoms ranged from 81% for upper respiratory symptoms to 97% for current asthma. For all symptoms kappas ranged from 59% to 90% indicating moderate to high reproducibility. Future research should now concentrate on validating the questionnaire as an indicator of mold growth.
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  • 17
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: There are few data sets appropriate for characterizing the indoor concentrations of air pollutants over the long term. An understanding of the variability in indoor pollutant levels is particulurly relevant to the design of epidemiologic investigations: misclassifiation of exposure due to the inaccuracy of exposure estimates tends to weaken the association of exposure with health outcome. This paper uses a series of indoor NO2 measurements collected at two-week intervals over 18-month periods between 1988 and 1991 to describe the seasonal and year-to-year variability in indoor NO2,. The data show that there can be large year-to-year differences in both the sample distribution of indoor NO2 as well as the household average. For homes with gas ranges with continuously-burning pilot lights, the average bedroom NO2 concentration was 25% higher in the winter of 1990-1991 than in the winter of 1989-1990 but only 4% higher during the winter of 1988-1989 than during the winter of 1989-1990. The winter-to-winter correlations within homes ranged from a low of 0.53 to a high of 0.88. The year-to-year differences in mean indoor concentrations were not related to temperature patterns. Occupant behaviors that influence air exchange rate and/or source use are hypothesized to be the major determinant of the observed pattern. Exposure data collected during a single year should be cautiously extrapolated to other years. However, in Albuquerque homes, the data suggest that the year-to-year variability in household NO2 levels will not have a strong impact on classifying exposure into broad categories.
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  • 18
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 19
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Microbial content in dusts such as bacteria, endotoxins and fungal spores are thought to be important causative agents for the symptoms in organic dust-related diseases. Micro-organism-induced mediator release was therefore examined in human cells. Bacteria were found to trigger the release of histamine and leurotriene B4 from bronchoalveolar cells, and in suspensions of dispersed lung and tonsillar cells they induce the release of histamine and prostaglandin D2. Basophil histamine release was triggered by both bacteria and their endotxins. Furthermore, histamine release caused by allergic as well as non-allergic reactions was enhanced by bacteria, endotoxins and fungal spores of mould. These effects of dust components may be crucial for the symptoms in q a n i c dust-related diseases, since the mediators are of key importance to the broncho-obstructive and inflammatory events in these disorders.
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  • 20
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The development of standardized non-culture-based approaches capable of assessing microbial contarnination of airborne dust is sorely needed. Direct chemical analysis has previously been successfully used for measuring components unique to Gram-negative bacteria. In the present study, dust from primary filters of hospital air-conditioning intake systems (which filter incoming outdoor and recirculated air) and dust from secondary room filters (filtering primarily indoor air) were analyzed. Dust from home air-condition-ing filters (which also filter outdoor air, with recirculation) were also analyzed. Muramic acid is an aminosugar present in Gram-positive and Gram-negative bacterial cell walls and can serve as a measure of bacterial contamination in dust. Samples were analyzed by gas chromatography-mass spectrometry after hydrolysis and conversion of released sugars (including muramic acid) to alditol acetates. Primary hospital filters contained 26.3 ± 10.0 ng of muramic acid/mg dust while secondary filters contained 5.3 ± 5.4 ng/mg. The level of inuramic acid in home air-conditioner dust was 31.7 ± 13.4 ng/mg. This study of dust collected from air-conditioners demonstrates the feasibility of chemical assessment of the microbial contamination of indoor air.
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  • 21
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 22
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A numerical study has been carried out to predict the indoor air quality in a newly painted partitioned office and to assess the effect of ventilation rate and partition layout on the pre-ventilation time required to allow the contaminant concentration level to drop to an acceptable level. The air-flow pattern, the time history of the average contaminant concentration level in the occupied zone, and the pre-ventilation time were computed by a CFD code with a K-ε turbulence model.A displacement ventilation system, with different operating conditions, was used to remove contaminants in the office. The VB emission model, developed by Guo and Tichenor (1992), has been improved to include the influence of non-uniform concentration distribution on contaminant emission rate from the paints. The average contaminant (VOC) concentration levels in the occupied zone and in each chamber were recorded hourly until the average concentrations in the office were less then 0.0005 g/m3.It has been found that the non-uniform concentration distri- bution greatly influences the decay rate of VOC emissions. The time required for the average concentration in each chamber to reach the threshold level is different, since they are non-uniform. The time differences between the chambers having the highest and lowest concentrations were 3 to 8 hours. The results also show that the time required to reduce the concentration in the occupied zone to the threshold level is dependent on the partition layout. For the same ventilation rate, the required time is approximately 4-8 hours longer when using a side layout than when using a central layout.
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  • 23
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 24
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A WHO/EURO working group met in Eilat, Israel, from 28 March to 4 April 1993, to assess the significance of risks to health associated with indoor radon, to develop a unified approach to control radon exposure, and to advise on the communication of associated health risks. A summary of the deliberations of this working group and its conclusions and recommendations are presented in this paper.
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  • 25
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Deciding between the different policy approaches available for reducing human exposures to indoor pollutants is an exceptionally complex task. These options can range from waiting until more definitive information is available to enacting regulatory standards, with many variations in between. This paper presents some of the factors policy-makers must consider in establishing indoor air quality policies, and the role researchers should play in ensuring that indoor air policies are based on the best available scientific information.
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  • 26
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The development of odor emission rates from EU6 classified glass fiber bag filters was studied in four air-handling units (AHU), and emissions from the same kind of filters with EU3 classified polyester prefilters were studied in two units. The filters were loaded in six AHU in downtown Helsinki. The pressure drop was measured, and the odors of the filters were evaluated by a trained panel under laboratory conditions (T = 20°C, face velocity 1.0 m/s) every sixth week. The odor emissions of simultaneous atmospheric dust samples were also studied. The odor emissions of the filters rose during the first three months to a level where every third person would be dissatisfied. The emissions from coarse prefilters were similar to those from the more efficient filters without prefilters, and the emissions of the main filters were significantly lower if used with prefilters. This result indicates that the prefilters effectively protected the fine filters from odor-causing particles. The results of tests made with atmospheric samples agree with this result. Relative odor emissions were the highest in coarse fractions (〉 10.0 μm). The pressure drop increased with the particle mass collected on the ventilation filter, but it did not correlate well with the odor emission of the filter. Thus, pressure drop alone is not an adequate criterion for changing supply air filters when hygienic aspects are a concern.
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  • 27
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Full-scale residential house tests were conducted to evaluate the effects of organic emissions from a wood finishing product – wood stain – on indoor air quality (IAQ). The test house concentrations of three alkane species, nonane, decane, and undecane, were measured as a function of time after the application of the wood stain. It was found that the test house concentrations can be simulated by an integrated IAQ model which takes into consideration source, sink and ventilation effects. The alkane emissions were controlled by an evaporation-like process. Data analysis indicated that there were significant sink effects in the test house. Different sink strengths were estimated by the model for the three alkane species. An inverse relationship between the test house sink strength and the alkane volatility was found.
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  • 28
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Settled household dust samples were collected from twelve dwellings in urban areas during an annual winter heating period. Emission of compounds from settled household dust was analyzed under simulated hot surface conditions with a temperature range of 50–300°C. The compounds were analyzed and identified by thermal desorption—gas chromatographic-mass spectrometric technique. The organic emission from household dust was relatively low at temperatures below 70° C, increased appreciably above 100°C, and gained in strength at temperatures above 200°C. Desorption of adsorbed compounds is the main contribution to emissions, but at higher temperatures the thermal degradation seems to affect also the quantity and the quality of the emissions. The organic composition of household dust was found to be equal in quality at different sampling sites; the emissions consist of mainly aliphatic aldehydes (C6—C13), aliphatic carboxylic acids and their esters (C8 C18, C6–C30) and phthalates. Phosphate esters, branched alkanes, n-alkenes, n-alkanones, monoterpenes, aromatic hydrocarbons, and aromatic and aliphatic alcohols were also well represented groups in household dust samples. The potential sources of identified compounds are discussed.
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  • 29
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The performance of sub-slab-ventilation (SSV) systems has been parametrically studied with a numerical model that was earlier compared successfully with experiment (Bonnefous et al., 1992). The model distinguishes between the sub-slab gravel and the underlying soil. It is used w examine system performance for the following system parameters: the permeability of the soil and of the sub-slab gravel, the magnitude of pressurization (or depressurization) applied by the SSV system, and the mode of SSV application (i.e. pressurization (SSP) or depressurization (SSD)). The mechanisms contributing to the successful performance of SSP and SSD systems are identified. For SSD systems, the mechanisms are (1) the inversion of the pressure gradient across the basement slab, and (2) the reduction of the radon concentration in the soil. For SSP systems, the mechanisms are (1) the elimination of convective flow of soil-gas from the soil into the sub-slab gravel by pressurization of the sub-slab region, (2) the reduction of the radon concentration in the soil, and (3) the suppression of diffusion of soil-gas from the soil into the sub-slab gravel by advective flow of air from the gravel bed into the subgravel soil. Numerical modeling demonstrates that placement of a sub-slab gravel layer substantially improves the SSV system performance. Except in the case of highly permeable soils, SSD systems are predicted to perform better than SSP systems. This prediction is consistent with reported field experience. The numerical model is used to elucidate the reasons for this difference in performance.
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  • 30
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 31
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 32
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A procedure is developed for assessing the health effects of the emissions from building products. The procedure is based on:〈list xml:id="l1" style="custom"〉•emission rates measured in environment test chambers•a fixed standard room with fixed standard conditions•a maximum acceptable concentration in the indoor air of each of the chemical compounds emitted, Iv a maximum permissible contribution to Iv from building products.The procedure has two elements: evaluation of the emitted compound alone and evaluation of the compound together with other compounds and indoor air factors. The evaluation includes odour and health effects of the compounds.The procedure has been applied to the emission test results for two building products: a rubber floor covering, and a water-borne acrylic watt paint.Maximum acceptable indoor air concentrations are listed fin-selected chemical compounds emitted by these two materials.
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  • 33
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Heat, mass and momentum transfer takes place simultaneously in ventilated rooms. For accurate predictions of the indoor environment, all the environmental parameters that influence these transport phenomena should be taken into consideration. This paper introduces a method for a full assessment of indoor thermal comfort using computational fluid dynamics in conjunction with comfort models. A computer program has been developed which can be used for predicting thermal comfort indices such as thermal sensation and draught risk. The sensitivity of predicted comfort indices to environmental parameters is analysed for a mechanically ventilated office. It was found that when the mean radiant temperature was considered uniform in the office, the error in the predicted percentage of dissatisfied (PPD) could be as high as 7.5%. The prediction became worse when the mean radiant temperature was taken to be the same as air temperature point by point in the space. Moreover, disregarding the variation of vapour pressure in the space resulted in an error in PPD of abour 4% near the source of moisture generation.The importance of evaluating both thermal sensation and draught risk is also examined. It is concluded that in spaces with little air movement only the thermal sensation is needed for evaluation of indoor thermal comfort whereas in spaces with air movement induced by mechanical vantilation or air-conditioning systems both thermal sensation and draught risk should be evaluated.
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  • 34
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), 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 test the effectiveness of individual commercially available portable indoor air cleaning units in removing dust particulates, tobacco smoke particulate and vapor phase constituents (nicotine and vinyl pyridine), viable and total fungal spores, pollen, and gaseous contaminants (carbon monoxide[CO], nitrogen dioxide[NO2], and formaldehyde[HCHO]), in a clean air test chamber. The air cleaner chamber results presented here represent initial-use results. In general, High Efficiency Particulate Air (HEPA) and electrostatic precipitator systems demonstrated the highest efficiencies with respect to particulate, contaminants, followed closely by electret filter systems. Ionizers and ozone generators were least effective in particulate removal. Systems which included sufficient sorbent material (i.e. activated carbon or potassium permanganate) were marginally effective at gaseous contaminant removal. None of the systems tested were effective at carbon monoxide removal.Sensory testing was conducted to discern potential correlation between human perceptive response and measured air cleaner performance (with respect to tobacco smoke removal). An electret filter (EF) loaded with carbon sorbent received the best ratings with respect to odor strength, nasal irritation, eye irritation, and overall air acceptability.
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  • 35
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 36
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 37
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A health and housing questionnaire was administered to children, ages 9-11, living in 24 communities in the United States and Canada. Logistic regression analysis examined the relationship between respiratory health symptoms (bronchitic, asthmatic and lower respiratory) and housing factors. The health risks (expressed as relative odds) were controlled for gender, parental asthma, parental chronic obstructive pulmonary disease and parental education, as well as between-city differences. Lower respiratory symptoms had significantly higher odds ratios reported in older homes (1.12), homes with smokers (1.24), air conditioners (1.14), air cleaners (1.37), and humidifiers (1.47). Home dampness (1.48) and the individual mold and water variables were all significantly associated with increased symptoms. Similar results were reported for bronchitic and asthmatic symptoms. While air conditioners and air cleaners were confounded with symptoms, humidifiers remained significant after controlling for childhood atopy.
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  • 38
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: In two case-referent studies the associations between questionnaire symptom reports, expressed as SBS (Sick Building Syndrome) in office workers or facial skin symptoms among VDT-workers, and physical data from offices in 160 buildings were investigated. The results show that low outdoor airflow rate and presence of certain pollution sources, such as copying machines, tended to be associated with an elevated prevalence of SBS. Buildings built or remodeled between 1977 and 1986, low-rise buildings with a horizontal roof and a foundation of the type “concrete slab on the ground”, as well as rooms with flourescent tube lighting with metal shields were also associated with higher SBS risks. A number of factors were associated with an overrepresentation of skin symptoms among VDT-workers such as type of foundation (concrete slab on the ground and crawlspace), the frequency of floor cleaning and type of lighting (fluorescent tubes with glass/plastic shields). It has not been possible to establish conclusive explanations for these associations. The difference in associations between building factors and S B S, and between building factors and skin symptoms among VD Tworkers points to different etiologies.
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  • 39
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Ozone concentrations were measured in indoor and outdoor residential air during the summer of 1992. Six homes located in a New Jersey suburban area were chosen for analysis, and each home was monitored for 6 days under different ventilation and indoor combustion conditions. The 5-hour average ozone concentration outdoors over the monitoring period was 95 ± 36 ppbv. One third of the days exceeded the National Ambient Air Quality Standard (NAAQS), one-hour maximum concentration of 120 ppb. The mean indoor to outdoor (I/O) ratios of ozone concentration ranged from 0.22 ± 0.09 to 0.62 ± 0.11, depending upon ventilation rate and indoor gas combustion. The presence of indoor gas combustion can significantly decrease the I/O ratio. Because of the great amount of time that people spend indoors, the indoor residential exposures were estimated to account for 57% of the total residential exposures. One type of the possible gas-phase reactions for indoor ozone, the reaction of ozone with a volatile organic compound containing unsaturated carbon-carbon bonds, is discussed with some supporting evidence provided in the study.
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  • 40
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Indoor air quality models are commonly based on the assumption of instantaneous and complete air mixing within a zone. Such an assumption is not appropriate for all circumstances, such as investigating the utility of segregating smokers to reduce nonsmoker exposure to environmental tobacco smoke. This experimental study characterizes quantitatively the rate at which smoke from a cigarette disperses within an unoccupied, 31-m3, low air-exchange rate room under natural convection flow conditions. Sidestream smoke from a smoldering cigarette was simulated with a pulsed release of a tracer gas – a neutrally buoyant mixture of sulfur hexafluoride (SF6) in helium – above an electrically heated coil. During each experimental run, sequential air samples were collected remotely, using gas-tight syringes, from 41 locations within the room. After each run, these samples were analyzed for SF6 content using a gas chromatograph with an electron-capture detector. Duplicate runs were conducted under three conditions: nearly isothermal surfaces; convection from a 500–watt heater; and convection from incoming solar radiation. Characteristic mixing times ranged from 7–10 minutes for the solar radiation case to 80–100 minutes for the nearly isothermal case.
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  • 41
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 42
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 43
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: One hundred and eighty eight Volatile organic compound (VOCs) were identified from dust emission, dust headspace, and in air sampling in a residence by sampling on Tenax TA followed by thermal desorption and HRGC/MS. Of these, 83 compounds were found in dust headspace. Aliphatic aldehydes (C4-8 and octane were major contributors to headspace gas chromatograms while the total ion current response for desorbed VOCs (120° C) was dominated by n-alkanes (C7-16), n- and branched alkanals (C4-10 and alkanoic acids (C2-14). Many of the identified VOCs could be products of microbial or human metabolism. Dust volatiles resulting from desorption were compared w dust headspace VOC analyses and found to be comparable considering the temperature difference. A method for determination of total VOC (TVOC-dust) emission at 120°C, was developed. Variation in desorption TVOC analyses was mainly due to sample heterogeneity.
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  • 44
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A test chamber has been developed in order to provide a small and simple emission testing facility capable of testing construction products in a climate where the important climatic parameters such as temperature, ventilation rate and air velocity can be varied independently around typical indoor values. The test chamber CLIMPAQ is made of panes of window glass. Other main surface materials are stainless steel and eloxated aluminium. The chamber has a volume of 50.9 litres and is designed to meet the requirements for quantifying air pollution. In this investigation human subjects acted as air pollution judges, and chemical characterization of the air pollution was carried out. Carpet, linoleum, wall paint and seal- ant were tested simultaneously in the CLIMPAQ and in four other chambers ranging from a full-scale chamber of 28 m3 to a field and laboratory emission cell of 3.5· 10−5m3. Product ranking is the same in all chambers for the sensory measurements. Emission rates based on sensory measurements differ for all products less than 100 % except for tests in a 3-litre chamber where emission rates were higher. Chemical measurements differ up to approximately 10 times for the same product in different chambers. Deviations appear to be the result of different environmental parameters in the various chambers. Low air concentrations or high specific ventilation rates seem to increase emissions, while differences in air velocities and sink properties may also be the cause of differences in emission rates.
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  • 45
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 46
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A review is presented of investigations of volatile organic compound (VOC) concentrations in indoor air of buildings of different classifications (dwellings, offices, schools, hospitals) and categories (established, new and complaint buildings). Measured concentrations obtained from the published literature and from research in progress overseas were pooled so that VOC concentration profiles could be derived for each building classification/category. Mean concentrations of individual compounds in established buildings were found to be generally below 50 μg/m3, with most below 5 μg/m3. Concentrations in new buildings were much greater, often by an order of magnitude or more, and appeared to arise from construction materials and building contents. The nature of these sources and approaches to reduce indoor air concentrations by limiting source VOC emissions is discussed. Total VOC (TVOC) concentrations were substantially higher than concentrations of any individual VOCs in all situations, reflecting the large number of compounds present, but interpretation of such measurements was limited by the lack of a common definition for TVOC relevant to occupant exposure.
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  • 47
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 48
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 49
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Indoor and outdoor aerosol sampling was conducted in two New York State Counties, Suffolk and Onondaga, during the period of January 6 and April 15, 1986. Week-long fine particle mass samples were collected indoors and outdoors for a total of 596 samples taken in 394 homes. The aerosol samples were analyzed by X-ray fluorescence for the following elements: Si, S, Cl, K, Ca, V, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Cd, and Pb. Lastly, aerosol mass concentrations were determined gravimetrically.Homes included in this study had one or more of the following sources: cigarette smoking, kerosene heaters, wood burning and gas stoves. Homes with none of the above sources were also included. Comparisons between mass and elemental concentrations among the different home groups allowed the investigation of the elemental profiles and importance of the indoor sources. From the five investigated sources, cigarette smoking was found to be the most important, and to a lesser extent, kerosene heaters. Finally, gas stoves did not contribute to the observed indoor aerosol mass and elemental concentrations, but other unknown indoor sources did contribute to indoor aerosol concentrations.Room-to-room differences in mass and elemental concentrations were also investigated. The results of these analyses suggested that concentrations measured in the living area and kitchen are identical, within analytical errors. Therefore, the indoor environment can be characterized as well mixed.
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  • 50
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 4 (1994), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Local age of air and air change effectiveness were determined in two office buildings using tracer gas techniques to study the applicability of the associated measurement procedures in mechanically ventilated office buildings. Measurement issues examined include the establishment of a uniform tracer gas concentration at the start of the test and the relationship of ventilation system configuration and system operation to the test procedure. Air change effectiveness was determined at locations in the occupied space based on the local age of air at that location and the age of air in the corresponding ventilation system return duct. Values of the air change effectiveness in the occupied space were generally close to one, which is consistent with good mixing of the Ventilation air within the occupied space. Deviations from 1.0, on the order of 10%, did occur, but given the limited experience with these measurement procedures in the field it is not clear whether these deviations are significant. These tests provide data on air change effectiveness to supplement the limited database on mechanically ventilated office buildings in the US. In addition, the experience obtained with the measurement procedures will assist in the development of a standardized approach to measuring air change effectiveness in the field.
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  • 51
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The installation of implants directly into extraction sockets offers considerable advantages over other treatment modalities for both practitioners and patients. Usually, immediate implants are placed and subsequently covered by mucosa allowing a submerged healing mode. This report presents the rationale, clinical procedures and results for immediate transmucosal implants. Following an intracrevicular incision and flap elevation, the tooth to be extracted is carefully luxated by means of small elevators to preserve the entire bony housing of the tooth. A titanium plasma-sprayed implant (ITI Bonefit®) is then installed at the bottom or in the wall of the extraction socket. An expanded polytetrafluoroethylene barrier membrane (Gore-Tex GTAM®) is tightly adapted around the implant post and over the bony margins of the alveolus. The flaps are then replaced, adapted around the neck of the implant and sutured. During nonsubmerged, transmucosal healing of the site, meticulous plaque control is performed by mechanical and chemical means. Membranes are removed after 5–7 months. Since infection was prevented, the implants obtained stability, healthy peri-implant mucosal tissues were observed and missing bone in the alveoli regenerated. Of 21 transmucosal implants placed into fresh extraction sockets, 20 yielded complete bone fill and coverage of the entire plasma-coated implants surface at the time of membrane removal. This documentation suggests that the immediate nonsubmerged installation of an implant into an extraction socket is a predictable treatment modality with good long-term prognosis.
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  • 52
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Histological examinations of clinically successful dental implants are very rare in the literature. This article presents a clinical case where an ITI hollow-cylinder titanium implant type F (red mark, 16 mm) had to be removed simultaneously with the resection of a squamous cell carcinoma of the lower jaw. The duration of functional loading of the implant was 49 months. The fixture was situated at the margin of the tissue to be resected during tumor surgery and could therefore be prepared as a histological specimen independent of the tumorous tissue. In the sections obtained. close contact of alveolar bone to the implant surface was clearly visible. Together with the clinical success of the implant, criteria of osseointegration seems to have been matched. This observation represents the longest histological survery of a clinically successful fixture of this implant system.
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  • 53
    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 explore the possibility of obtaining bone regeneration in jaw bone defects in rats after coverage of the defects with an occlusive bioresorbable membrane. The experiment was carried out in 31 rats. The mandibular ramus was exposed in both sides and a 2 x 3 mm defect was produced at its lower border. A gutta-percha point was placed to indicate the original level of the border. The defect on one side was covered with a polyhydroxybutyrate resorbable membrane, whereas the contralateral side received no membrane before closure of the wound. Macerated jaw specimens representing 3 and 6 months of healing demonstrated minimal bone fill in the control defects, whereas all test defects healed to or close to the gutta-percha point, indicating the original inferior border of the jaw. The histological analysis demonstrated increasing bone fill in the test specimens from 15–180 days, whereas only 35–40% of the defect area in the control sides was filled with bone after 3–6 months. Ingrowth of muscular. glandular and connective tissue was consistently occurring in the control defects during healing. It can be concluded that selective repopulation of bone defects with bone-forming cells can be ensured by excluding surrounding soft tissues from the wound area with an occlusive bioresorbable membrane.
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  • 54
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This retrospective study describes the effect of smoking on initial fixture failure before functional loading with fixed prosthetic restorations. Of 208 installed Brånemark fixtures in the mandible, only 1 failed (0.5%) and no detrimental effect of smoking on fixture survival could be detected. In the maxilla, 101244 fixtures failed (4%); 7778 fixtures failed in smokers and 31166 in nonsmokers. The failure rate before loading was 9% in smokers versus 1% in nonsmokers and was statistically significant, despite the fact that bone quality in both groups was comparable. Failed fixtures occurred in 31% of the smokers, despite often excellent bone quality, long fixture length or good initial stability. Only 4% of the nonsmokers had failures, in most cases related to poor bone quality. It is concluded that smoking is a significant although not the only important factor in the failure of implants prior to functional loading. Prospective studies are needed to assess the risk of implant failure in conjunction with smoking. In the mean time, patients should be informed of the adverse effect of smoking.
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  • 55
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to compare the clinical and microbiological (microscopic) parameters during the development of experimental gingigivitis and experimental peri-implant mucositis. Twenty partially edentulous patients were treated for moderate to advanced periodontal disease. Following active periodontal therapy consisting of motivation, instruction in oral hygiene practices, scaling and root planing and periodontal surgery where indicated, IMZ oral implants were incorporated in posterior edentulous areas. After 3 months of healing, the prosthetic abutments were connected, and the patients were closely supervised for another 2 months of healing. At this time, baseline data were obtained. Re-examinations were scheduled at 3 and 6 months. Following this, the patients were asked to refrain from oral hygiene practices for 3 weeks. At all examinations including the end of the period of no oral hygiene, the following clinical parameters were obtained: Plaque Index, Gingival Index and Sulcus Bleeding Index, all modified by Mombelli et al. (1987) probing pocket depths and recession in mm. Furthermore, submucosal/subgingival plaque samples were obtained and analyzed using phase contrast microscopy. At the end of the 3-week period of plaque accumulation: optimal oral hygiene was reinstituted. There were no statistically significant differences between the mean values of all parameters at implant compared to tooth sites at any observation periods. The period of no oral hygiene demonstrated a similar cause-effect relationship between the accumulation of bacteria1 plaque and the development of peri-implant mucositis as established for the gingival units by the experimental gingivitis model.
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  • 56
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have previously suggested that altering the height of the porous-coat segment of a partially porous-coated TiAl6V4 endosseous dental implant would affect the degree of crestal bone loss occurring during implant function by changing the patterns of stress transfer. This conclusion arose from the analysis of data from several different experiments and lacked a direct intra-animal comparison. In the present study we have compared two implant designs varying only in the extent to which they were porous-coated. With one design (type A) the coronal 1.8 mm of the implant root had a machined surface while the remainder of its length was porous-coated with TiAl6V4 beads. The other design (type B) had all but the coronal-most 0.75 mm porous-coated. Two implants of each type were placed in each of 4 dogs and the sites allowed to heal for 4 weeks before re-entry and prosthesis attachment. Monthly the implant-supported bridges were removed and radiographs exposed of each implant using a special film holder connected separately to each implant. These radiographs were analyzed for crestal bone loss using both direct visual and computer-assisted techniques. The results showed that bone remodelled to the machined surface-to-porous coat junction for type B implants and achieved a steady state by 12 weeks of function, whereas a longer time was required to achieve this state with type A implants. Significantly more bone loss occurred with the type A design, and this difference was detectable as early as after the first month of function.
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  • 57
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In this article we describe the implantation of ITI implants in combination with bone grafts. Two different cases were considered: the augmentation of an atrophic maxilla or mandible where the transplant was fixed by means of ITI implants and the implantation into free transplants fixed by means of the THORP reconstruction plate system. These indications require 2-stage procedures with submerged implants and transplants during the healing period. For this new applications, standard ITI implants were combined with specially developed new transgingival units of high manufacturing precision. The new design resulted in a maximum tightening moment of 4.0 N.m versus 1.25 N.m achievable with a conventional 2-mm screw. Dynamic testing showed that, for the range of tightening moments of 0.25 N.m up to 1.0 N.m, the loosening moment after 2,000,000 cycles remained approximately 10% above the tightening moment. For the clinical application a tightening moment of 0.35–0.5 N.rn is recommended. The special design and the high precision of the extension parts results in a tight adaptation between the primary implant and the extension parts, which may be important for microbiological reasons.
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  • 58
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A clinical and radiographical study was performed to evaluate whether initial submergence of titanium fixtures is an obligate treatment measure for the establishment of proper bone anchorage when implants a.m. Brånemark are used. The sample was comprised of 11 subjects with edentulous mandibles. A split-mouth design was employed; in the right mandibular quadrant a traditional 2-step procedure for fixture installation and abutment connection was utilized, while in the left quadrant a 1-step procedure was carried out, i.e., fixtures were placed and abutments were connected in one and the same session. Three to 4 months after fixture installation, fixed bridgeworks were fabricated and rigidly connected to the implants. Clinical examinations (including probing pocket depth, bleeding on probing and implant stability test) were performed after 12 and 18 months. Radiographs were taken following insertion of the bridges and at the 12- and 18-month re-examinations. The probing pocket depth, the bleeding on probing, the implant stability and the radiographic determinations were similar for the 2 groups of treatment alternatives. This indicates that titanium fixtures a.m. Brinemark can be properly anchored (osseointegrated) in mandibular bone and successfully used for bridge retention also when a 1-step procedure is used for implant installation.
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  • 59
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to evaluate the use of a biodegradable membrane of polyhydroxybutyrate-hydroxyvalerate copolymer reinforced with polyglactin 910 fibers, as an occlusive barrier over implants placed into fresh extraction sockets. Ten dogs had the 3rd and 4th mandibular premolars extracted bilaterally. Each dog had 4 Astra Dental Implants® placed directly into the fresh extraction sockets. The top of the fixtures was placed at the same level as the top of the buccal cortical bone. The two implants in the right side were covered with the hydrolyzable polyester material (polyhydroxybutyrate-hydroxyvalerate reinforced with polyglactin 910 fibers; PHB-HVIPG). and the 2 implants in the left side were controls without occlusive membranes. Soft tissue dehiscences were registered for half of the implants in the test side but were not noted in the control side. The histomorphological measurements after 12 weeks showed that the mean distance from the top of the fixtures to the first bone-to-implant contact was significantly greater than for the control side. The membrane-covered implants without dehiscences showed also significantly less bone fill compared with the control side. Inflammatory cell infiltrates were seen adjacent to all PHB-HVIPG membranes, and frequently the membrane material was surrounded by a fibrous tissue capsule. The polyester membranes used in this study interfered with the marginal bone healing adjacent to the immediately placed implants. An increased inflammatory reaction and significantly less marginal bone healing was registered in the membrane side compared with the control side.
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  • 60
    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 evaluate the soft tissue conditions at osseointegrated oral implants in relation to the width of masticatory mucosa. Thirty-nine patients who had received a full-arch fixed bridge reconstruction ≥ 10 years ago or a partial reconstruction ≥ 5 years ago on a total of 171 implants ad modum Brsnemark were included in the study. The examinations involved assessments of plaque, gingivitis, bleeding on probing, probing depth, width of masticatory mucosa and marginal tissue mobility. Simple correlation analysis as well as multiple regression analysis were performed to evaluate relationships between recorded parameters. The results showed that 24% of the sites were lacking masticatory mucosa, and an additional 13% of the implants had a width of less than 2 mm. Mobility of the facial marginal soft tissue, i.e., lack of an attached portion of masticatory mucosa, was observed at 61% of all implants. No major differences in the clinical parameters examined were found between sites with and without an “adequate” width of masticatory mucosa. Multiple regression analyses revealed that neither the width of masticatory mucosa nor the mobility of the border tissue had a significant influence on (i) the standard of plaque control or (ii) the health condition of the peri-implant mucosa, as determined by bleeding on probing. Hence, the study failed to support the concept that the lack of an attached portion of masticatory mucosa may jeopardize the maintenance of soft tissue health around dental implants.
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  • 61
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Removal of plaque and calculus by means of sonic and ultrasonic scalers causes considerable damage to implants. With a view to avoiding the aggressive effects of these instruments, an experimental study was carried out for which conventional sonic and ultrasonic scalers were coated with Teflon®. The effects of these instruments on implant surfaces was then compared with that of plastic and metal implant curettes. Stereo-microscopy, scanning electron microscopy and surface profilometry were used to detect and record damage to implant surfaces and changes in surface roughness. Generation and propagation of heat in subgingival simulation of use of sonic and ultrasonic scalers were also recorded by means of temperature measurements at the implant surface. The results revealed that no discernible damage was caused by Teflon-coated sonic and ultrasonic scalers or implant curettes made of plastic on smooth titanium surfaces. Instrument material residues were found on rough implant surfaces. It was not the intention of this study to provide an analysis of the prerequisites for the cleaning of rough implant surfaces. but rather to determine what type of damage is to be expected when contact is made with smooth and rough surfaces unintentionally. Temperature measurements during the subgingival use of sonic and ultrasonic scalers indicated satisfactory functioning of the cooling system. Coating of sonic and ultrasonic scaler tips with Teflon thus facilitates the use of high-frequency instruments to achieve professional cleaning of implants.
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  • 62
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of the present study was to investigate whether it is possible to increase the height of the rat mandible at its inferior border using a bioresorbable membrane adapted to create a secluded space for ingrowth of bone tissue. The experiment was carried out in 18 rats. The mandibular ramus was exposed at both sides. A standardized titanium microimplant was then inserted in the naturally existing curvature at the inferior border of the mandible, serving as a fixed reference and space maker. The mandibular border on one side was covered with a polyhydroxybutyrate bioresorbable membrane, and the contralateral side, serving as control, received no membrane before closure of the wound. The membranes were placed in such a way that a space was created in the curvature between the membrane and the inferior border of the mandible. Macerated jaw specimens representing 6 months of healing demonstrated substantial amounts of bone formation in the curvature of the inferior border of the mandible, resulting in a flattening of the inferior border. Negligible amounts of bone formation had occurred in the control sides. Histological analysis demonstrated that. in 4 of 6 experimental specimens, the space created by the membrane was completely filled with new bone after 6 months of healing, but in some specimens soft tissue seemed to have migrated into the space through ruptures of the membrane or because of poor membrane adaptation at its lateral borders, thereby inhibiting bone formation. Only negligible bone formation had occurred at the control sides. It can be concluded that augmentation of the mandible can be accomplished using a bioresorbable membrane of polyhydroxybutyrate adapted to create a secluded space for ingrowth of bone tissue. but the membrane must be modified regarding its physical properties before clinical use in maxillofacial surgery.
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  • 63
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this study was to evaluate the ability of computer-assisted densitometric image analysis (CADIA) to detect small changes in mineralized and nonmineralized tissues adjacent to dental implants and to correlate these changes with CADIA values. A section of a pig mandible including all soft tissues and in which a hollow cylinder ITI Bonefit® implant with an artificial mesial and a buccal infrabony defect was placed was used to obtain pairs of standardized radiographs. Series of radiographs were obtained with exposure times of 0.13. 0.20, 0.44. and 0.53 s. Specimens of mineralized or nonmineralized tissues were placed arbitrarily in the defects before each radiographic exposure. The radio-graphs were captured through a video camera, digitized and stored in a personal computer. Every radiographic image was then subtracted from a baseline one without any change. The result of the subtraction was evaluated with CADIA. A linear correlation (r2=0.99) was found between the bone chips (1–5 mg of dry weight) placed in the mesial defect and the CADIA values. Bone chips in the buccal defect (behind the implant), however, were not detected unless their weight reached 14 mg or more. For conventionally exposed radiographs, it was not possible to recognize soft tissue specimens (1–6 mg), either in the buccal or the mesial defect. However, when “underexposed” radiographs (exposure time: 0.13 s) were obtained, a linear correlation (r2=0.80) was calculated for soft tissue specimens in the mesial defect and CADIA values. In normally exposed radiographs. the CADIA system could detect even the smallest change in bone density (bone chip of 1 mg of dry bone weight) and correlated almost linearly with these changes. Provided that the radiographic images are obtained with standardized geometry and normal exposure time. the tissue density changes detected by this system within bone defects represent only mineralized tissue changes. By underexposing radiographs, CADIA may even reveal soft tissue changes around dental implants.
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  • 64
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A single tooth implant was placed in a boy aged 12 years and 3 months. The case has been followed for more than 4.5 years. The fixture did not move together with the adjacent teeth as the maxillary growth went on. There was no “loss” of marginal bone on the side of one adjacent tooth where the distance between implant and tooth was appropriate. But a “loss” of marginal bone (measured from the cemento-enamel junction) was noted on the other adjacent tooth where the fixture had been placed 1 too close to the tooth.
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  • 65
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Periodontal probing is commonly used for assessing both the status of gingival health and the connective tissue attachment level around teeth.The role of probing around endosseous implants still remains unclear. The purpose of this study was to determine the histological level of probe penetration in healthy and inflamed mucosal tissues around implants. Five beagle dogs were used and a total of 30 one-stage. Titanium Plasma Spary (TPS)-coated implants of the ITI type were placed in the mandibles. After the healing period with meticulous oral hygiene. the dogs were divided into 3 groups: 1) clinical healthy mucosal tissues; 2) experimental mucositis (3 dogs); and 3) experimental ligature-induced peri-implantitis (2 dogs). Four months after implant placement, respectively 6 months in the third group, 60 probes were placed with a standardized force of 0.2 N and fixed at the mesial and distal aspects of the implants. Probing depth. clinical attachment level (CAL), Plaque index (PII) and Gingival Index (GI) were assessed throughout the study. Tissue sections were obtained for histometrical analysis. In the healthy group, the mean PII was 0.47. the GI 0.06 and the clinical probing depth (CPD) 2.12 mm. In the mucositis group the PII was 1.61, the GI 1.61 and the CPD 1.87 mm. In the peri-implantitis group the PII was 1.96, the GI 2.05 and the CPD 3.73 mm. The histologic results show that the probes were able to identify the connective tissue adhesion level in the healthy group with a mean error of −0.05 mm (mean histologic probing depth (HPD): 1.75 mm) and, in the mucositis group, with −0.02 mm (mean HPD: 1.62 mm). Probe penetration increased with the degree of inflammation and in the peri-implantitis group the probe exceeded the connective tissue level by a mean 0.52 mm (mean HPD: 3.8 mm). Therefore, probing around implants represents a good technique for assessing the status of peri-implant mucosal health disease.
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  • 66
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this investigation was to evaluate whether titanium endosseous implants would osseointegrate in dog alveolar ridges augmented by allogenic material. In 8 dogs en bloc resection, including 2 premolars, was performed bilaterally in the maxilla and the mandible. After a healing period of 6 weeks allogenic, demineralized and lyophilized dentin or bone was implanted subperiosteally. Titanium implants were installed 5.5 months later in some of the regions. Light and fluorescence microscopic evaluation revealed fibrous encapsulation of the implanted allogenic material, no osteoinduction and only minimal osteoconduction. few multi-nuclear giant cells and a sparse inflammatory reaction. The titanium implants healed mainly by fibrous encapsulation.
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  • 67
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study examined in vitro the existence of microbial leakage along the components of the Brånemark® implant system. Thirty-two implant/abutment assemblies were installed in a liquid blood medium previously inoculated with oral micro-organisms. To examine the leakage at the implant abutment interface, 16 assemblies were partially immersed. The remaining 16 were completely immersed to observe the leakage at both the implant abutment and abutment-prosthesis interface. After 7 days of an-aerobic incubation, the micro-organisms in the internal part of the implants were collected and incubated on blood agar plates in anaerobic conditions. Micro-organisms were found in the completely immersed assemblies and at lower numbers in the partially immersed implants, indicating that bacterial leakage at both levels seems to exist. Several penetrating bacteria have been associated with peri-implantitis. The clinical importance of this bacterial leakage is not yet well understood. Although the longevity of the Brånemark® implants is well documented, this bacterial leakage might play a role in peri-implantitis. both in the etiology as well as in the treatment.
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  • 68
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to analyse the distribution of interstitial collagenous and noncollagenous glycoproteins of keratinized mucosa surrounding successful endosseous implants. Biopsies were incubated with highly purified antibodies against types I. III. IV collagen. laminin and fibronectin and routinely observed by immunofluorescence staining. Whereas no significative difference in the distribution of collagenous components was observed in comparison with healthy human gingiva, the collagen fibers of the connective tissue attachment ran parallel to the long axis of the implant. In 50% of the biopsies the gingival connective tissue underlying the junctional epithelium was rich in inflammatory cells and poor in collagenous components. However, the increased staining of type III collagen and the intense presence of fibronectin in this area reflect the very important remodeling ability of the local keratinized mucosa.
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  • 69
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this investigation was to test the hypothesis that membrane permeability is necessary in bone formation using the principle of guided tissue regeneration. On the forehead of 8 rabbits. titanium test cylinders were anchored in the calvaria. These cylinders were either covered by an expanded polytetrafluoroethylene (e-PTFE) membrane generating a chamber for bone formation or they were sealed off by cast titanium. The implanted cylinders were covered by resuturing the periosteum and the cutaneous flap. After 8 months of healing. new bone had formed in all cylinders in all animals irrespective of whether the chamber for bone formation was sealed off by cast titanium or the e-PTFE membrane. Based on these results, we conclude that permeability of the membrane is not necessary in the guided generation of new bone.
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  • 70