Biomedical subjects

Olaf Bernhardt

Publications and source records attributed to Olaf Bernhardt.

25 records · Page 2Linked to original sources

PubMed2002

Methodology of three-dimensional determination of root surface roughness.

In comparing and evaluating the instruments that are used in root debridement, roughness constitutes a standard variable that is assessed. The purpose of this study was to describe the conditions and requirements for the three-dimensional roughness measurements of tooth roots using a laser profilometer. Impressions were made of 60 instrumented and 12 untreated root surfaces, which were then measured using a dynamically focussing optical profilometer (Mikrofocus, UBM, Karlsruhe, Germany). To separate roughness from the form of the tooth, a low pass filter was applied. This meant that the longer wavelengths - which roughly approximated the root forms - were subtracted from the measured profile. We then used an individualized Fourier transformation to define the threshold at which roughness becomes waviness. Roughness parameters were Ra (average roughness) and Rz (average roughness in the z dimension) for two- and three-dimensional measurements. To describe the requirements for the measurement, we studied the effect of pixel density and the field size on the average roughness value, Ra. We found that Ra increases with pixel density until 400 per mm is reached, after which it does not change meaningfully. Furthermore, Ra is highly dependent upon the area of the field to be scanned, increasing in line with the area, and does not approach one value within the surface available on one tooth. The correlation coefficients between the two-dimensional and three-dimensional Ra and Rz values ranged from 0.7 to 0.8. We conclude that roughness values are strongly dependent on the measurement conditions and the results of one study cannot be directly compared to another. In addition, it was found that two-dimensional measurements are sufficient for characterizing root surfaces.

Dental Scaling↗

PubMedDate not supplied

Prosthodontic status among old adults in Pomerania, related to income, education level, and general health (results of the Study of Health in Pomerania, SHIP).

PURPOSE: The aim of the study was to evaluate associations among prosthetic status, socioeconomic factors, and general health of subjects aged 55 to 79 years. The data were taken from the Study of Health in Pomerania (SHIP). MATERIALS AND METHODS: Socioeconomic information (age, sex, education level), medical information (number of diseases), and details on smoking and alcohol consumption were obtained. Prosthetic status in the maxilla and mandible was classified into complete denture (CD), removable partial denture (RPD), > or = 10 natural teeth or teeth replaced with fixed prosthodontics (10T+), and < or = nine natural teeth including fixed prosthodontics (9T-). RESULTS: The data of 1,877 subjects were evaluated. CDs in the maxilla were more frequent than in the mandible. RPDs were more frequent in the mandible and in the group aged 65 to 74 years. Of the individuals with a low education level, 47% had a CD in the maxilla, and only 21% had 10T+. However, of subjects with a high education level, 22% had a CD in the maxilla, and 54% had 10T+. The odds ratio of having a CD in the maxilla increased to 11.9 at the age of 75 to 79 years, compared to 0.6 at the age of 55 to 59 years. Logistic regression analyses showed that the risk of wearing a CD was significantly associated with old age, low education level, low income, smoking, and alcohol abuse, whereas the number of diseases (used as an indicator of general health) was not. CONCLUSION: Alcohol abuse, smoking, low education level, low income, and old age were significant predictors of wearing CDs.

Age Factors↗

PubMedDate not supplied

Anaerobic microflora under Class I and Class II composite and amalgam restorations.

OBJECTIVES: The microflora around and beneath restorations is an important factor of restoration failure. The aim of this pilot study was to determine and compare the microbial spectrum under composite and amalgam restorations with special attention to the anaerobic flora. METHOD AND MATERIALS: Ten composite and five amalgam restorations scheduled for replacement were clinically evaluated for marginal gaps, fractures, and secondary caries. After their removal and caries diagnosis, a dentin sample just below the restoration was taken under sterile conditions, stored in a prereduced transport medium for anaerobic bacteria, and immediately transferred to a laboratory for microbial diagnosis. RESULTS: The clinical parameters showing mostly moderate marginal imperfections and the ratios of aerobic to anaerobic flora were comparable for composite and amalgam restorations (11.4%:88.6% and 15.4%:84.5%, respectively). The microbial variety under composite restorations was much greater compared to amalgam, and it was similar to that of infected root canals including anaerobic gram-negative rods, such as Fusobacterium species or Porphyromonas species. Beneath amalgam, the microbial flora was similar to the one found in carious dentin and plaque, with anaerobic and facultatively anaerobic gram-positive rods dominating. Quantitatively, there were up to eight times more microorganisms under composite restorations. The number of bacterial strains correlated with the caries activity and the filling material, the number of anaerobic rods correlated highly with caries activity and localization. In a linear regression, caries activity and the filling material had statistically significant influence on the bacterial load. CONCLUSION: Although caries activity and location had the greatest influence on the microbial flora under the restorations, the kind of restoration material seemed to have an additional effect on the composition of the microflora. This pilot study indicates that inadequate composite restorations may promote the growth of cariogenic, as well as obligate anaerobic and potentially pulpopathogenic bacteria, which should be confirmed by further studies.

Bacteria, Aerobic↗

PubMedDate not supplied

Study of Health in Pomerania (SHIP): Relationship among socioeconomic and general health factors and dental status among elderly adults in Pomerania.

OBJECTIVE: The aim of this study was to evaluate associations among the dental status, socioeconomic factors, and general health of 1,877 subjects between the ages of 55 and 79. METHOD AND MATERIALS: Socioeconomic information (age, sex, education level) and questions on smoking and alcohol abuse were taken from an interview; income and medical information (number of diseases) were taken from a self-administered questionnaire; and HbA1C and CDT (diabetes and alcoholism markers) were taken from blood analyses. RESULTS: Of the subjects, 73% had a low education level, and 27% of the subjects had a monthly income of < 1,000 Euro and 13% of > 2,000 Euro. Twenty-six percent of the subjects were edentulous, and 29% had 20 or more teeth. The odds ratio of edentulism increased to 9.0 (95% confidence interval = 7.0-11.5) at the ages of 75 to 79 years compared to ages 55 to 79. Logistic regression analyses showed that edentulism was significantly associated with age, low education level, low income, smoking, and alcohol abuse. However, the retention of more than 20 teeth was associated with age. CONCLUSIONS: Age, low income, low education level, smoking, and alcohol abuse seemed to be risk markers for edentulism; whereas, the number of diseases, diabetes, and gender were not.

Age Distribution↗

PubMedDate not supplied

Risk factors for high occlusal wear scores in a population-based sample: results of the Study of Health in Pomerania (SHIP).

PURPOSE: Using a population-based sample of the cross-sectional epidemiologic "Study of Health in Pomerania" (SHIP), this study evaluated whether certain occlusal and sociodemographic factors besides age and gender are risk factors for high dental wear. MATERIALS AND METHODS: Medical history and dental and sociodemographic parameters of 2,529 dentate subjects selected representatively and according to age distribution were checked for correlations with the occurrence of high occlusal wear symptoms using a multivariate logistic regression model. Occlusal wear was recorded using the attrition index by Ekfeldt et al and was age adjusted by determining high occlusal wear for every 10-year age group as index values > or = 90th percentile. RESULTS: The following independent variables were found to be correlated with high occlusal wear: male gender, odds ratio 2.2; frequent bruxism, odds ratio 2.5; loss of molar occlusal contact (Eichner classification), odds ratio from 1.5 to 3.1; edge-to-edge relation of incisors, odds ratio 1.7; unilateral buccolingual cusp-to-cusp relation, odds ratio 1.8; and unemployment, odds ratio 1.6. In contrast, anterior cross-bite, unilateral posterior cross-bite, and anterior crowding were protective for high occlusal wear levels, as shown by significantly reduced odds ratios. Gender-separated analysis showed that self-reported bruxism was a risk factor only for men. CONCLUSION: In addition to some occlusal factors, the main factors associated with occlusal wear were bruxism and gender.

Adult↗

PubMedDate not supplied

Gender differences in associations between occlusal support and signs of temporomandibular disorders: results of the population-based Study of Health in Pomerania (SHIP).

PURPOSE: The aim of this study was to investigate whether gender-dependent associations exist between signs of temporomandibular disorders (TMD) and occlusal support. MATERIALS AND METHODS: Stratified by gender, the data of 2,963 35- to 74-year-old participants from the epidemiologic Study of Health in Pomerania were used in logistic regression analyses with temporomandibular joint (TMJ) tenderness and muscle tenderness as the dependent variables. Occlusal support was classified according to the Eichner index, a classification system based on occluding pairs of teeth. The final model was adjusted for bruxism, age, and various sociodemographic data. RESULTS: Logistic regression analyses revealed increased odds ratios for TMJ tenderness in men with loss of all four molar and premolar supporting zones (odds ratio 3:9) and without antagonist contact (odds ratio 2:7). Significant relationships in men were also found between muscle tenderness and loss of one (odds ratio 2:1), three (odds ratio 2:1), or four supporting zones (odds ratio 2:7), and loss of any tooth contact (odds ratio 2:3). In women, significant associations between occlusal support and TMD signs were absent. Subjects with bruxism were more likely to have TMJ tenderness (odds ratio women 2:0, men 1:9). In women, an additional relationship existed between bruxism and muscle tenderness (odds ratio 1:7). The following habits showed no significance: gum chewing, unilateral chewing, and lip/tongue/cheek biting. CONCLUSION: Only in men was the loss of occlusal support significantly associated with muscle and TMJ tenderness. The association between bruxism and TMD signs supports the theory that repetitive adverse loading of the masticatory system may cause functional disturbances.

Adult↗

PubMedDate not supplied

The impact of tooth loss on general health related to quality of life among elderly Pomeranians: results from the study of health in Pomerania (SHIP-O).

PURPOSE: It is important to know whether tooth loss has an impact on an individual's quality of life, since tooth loss is common. The aim of this study was to determine whether oral status is associated with general health and related to quality of life. MATERIALS AND METHODS: Data of 1,406 subjects aged 60 to 79 years were taken from the Study of Health in Pomerania (SHIP). Sociodemographic (age, sex, and education level) and medical information (including the most common diseases in Germany) were gathered through an interview, and income data were obtained from a self-administered questionnaire. The prosthetic status in the maxilla and mandible was classified into complete denture or removable partial denture or with > or = 10 natural teeth including teeth replaced with fixed prosthodontics (> or = 10T) or with < or = 9 natural teeth including fixed prosthodontics (< or = 9T). The health-related quality of life was measured using the Short Form (SF-12) questionnaire. Multiple linear logistic regression analyses were used to identify the nonstandardized beta coefficient using physical and psychologic indices from the SF-12 as dependent variables and sociodemographic information, prosthetic status, and disease state as independent variables. RESULTS: Prosthetic status is related to the physical scale of the SF-12. Additionally, we found that < or = 9T had a significant effect on the physical index of general health-related quality of life. CONCLUSION: Reduced dentition without replacement of missing teeth by removable or fixed prosthodontics reduces the physical index of quality of life to the same extent as cancer or renal diseases.

Aged↗