Influence of Age and Tooth Loss on Masticatory Muscles Characteristics: A Population Based MR Imaging Study.

BACKGROUND: Aging is associated with a decline in masticatory muscles mass and performance. The present study aims to examine the differences in the cross-sectional areas of the masseter, medial and lateral pterygoid muscles in relation to age and the present dental status in a population-based magnetic resonance imaging study. METHODS: This cross sectional study involved 747 subjects aged between 30-89 years (344 male, 403 female) who underwent both a whole body MRI and a full oral examination. The cross-sectional areas of the masseter, medial and lateral pterygoid muscles were measured from MRI images using the software Osirix. Dental and prosthetic status data from the oral examination were classified according to Eichner index. The method of generalized least squares, also called growth curve model, was used to examine the associations between the cross-sectional areas, age and tooth status. RESULTS: The cross-sectional area of the lateral pterygoid muscle decreased substantially with age in women but did not depend on age in men. The medial pterygoid muscle depended on age but an effect modification by gender was uncertain. Masseter muscle was weakly associated with age but strongly associated with the number of teeth in both genders. CONCLUSIONS: Our findings suggest that age has a heterogeneous effect on masticatory muscles. This indicates that age related changes to the masticatory muscles are muscle specific and are not consistent between the different muscles.

Effect of body shape and inflammation on tooth loss in men and women.

OBJECTIVES: Android and gynoid adiposity is differently involved on inflammatory responses in men or women in periodontitis and tooth loss. We tested the hypothesis whether identical waist-to-hip ratios (WHR) in men and women could abolish this disparity. MATERIALS AND METHODS: Data of 2746 participants from the Study of Health in Pomerania (SHIP) were analysed. Men and women were 1:1 matched, N = 344:344, in three age strata for waist-to-hip ratio. We determined anthropometric measures, attachment loss, tooth loss and markers of systemic inflammation. RESULTS: Women matched with men by WHR had increased periodontal measures as compared to women of the general population. Nevertheless, in the matched pairs incidence risk (IRR) ratios for any tooth loss associated with elevated C-reactive protein were IRR = 2.15 (CI 1.33-3.40) and 1.04 (0.66-1.66) in men and women, respectively. Regression with tooth loss due to any cause as dependent variable showed dose dependency on C-reactive protein levels in men but not in women. The adjusted IRR associated with high C-reactive protein in men was 1.37 (CI 1.05-1.78) and 2.63 (1.58-4.38) in general and in matched subjects, respectively. CONCLUSION: Systemic inflammation was associated with tooth loss in men but not in women even in women with wide girth. Despite worsened periodontal measures and inflammation in women matched for body shape with men, these women do not lose more teeth even when they are exposed to increased markers of systemic inflammation. CLINICAL RELEVANCE: This is an attempt to disentangle the unclear relationship between obesity and periodontitis, both of them having public health relevance.

Exome Variant Analysis of Chronic Periodontitis in 2 Large Cohort Studies.

Periodontitis is characterized by inflammation of the gingival tissue. The main risk factors are socioeconomic factors, sex, age, smoking, and diabetes, but periodontal disease has also a genetic background. Previous genome-wide association studies failed to reveal genome-wide significant associations of single common single-nucleotide polymorphisms with chronic periodontitis. Using the Illumina ExomeChip data of 6,576 participants of the German population-based cohort studies Study of Health in Pomerania (SHIP) and SHIP-Trend, the authors performed single variant and also gene-based association studies of rare and common exonic variations on different periodontal case definitions. Although our study comprised the largest sample size to date to assess genetic predisposition for chronic periodontitis, the authors found no significant association. This study emphasizes that for chronic periodontitis, large sample sizes will be necessary to find genetic associations, even when examining rare genetic variants.

Association of Periodontal Destruction and Diabetes with Mortality.

Current evidence indicates the effects of periodontitis on diabetes as well as mortality, for which diabetes itself represents a risk factor. However, the possible interaction of these 2 chronic conditions regarding mortality has not yet been investigated. Therefore, the purpose of this study was to evaluate whether periodontal destruction interacts with diabetes on all-cause and cardiovascular disease (CVD) mortality or if diabetes serves as a mediator in this association. The study sample comprised 3,327 participants aged 20 to 81 y from the Study of Health in Pomerania. Periodontal destruction was assessed via clinical attachment level (CAL) and the number of missing teeth. Information on mortality (date and ICD-10 code) was ascertained from death certificates. Directed acyclic graphs were used to identify potential confounders, and Cox proportional hazard models were applied. In 36,701 person-years of follow-up, 263 study participants deceased, 89 due to CVD. Fully adjusted main effect models resulted in hazard ratios of 1.01 (95% confidence interval [95% CI]: 1.002 to 1.01) for extent of CAL ≥3 mm, 1.10 (95% CI: 1.03 to 1.18) for mean CAL, and 1.03 (95% CI: 1.01 to 1.04) for the number of missing teeth regarding all-cause mortality. Analogous results were obtained for CVD mortality, with hazard ratios of 1.01 (95% CI: 0.99 to 1.02), 1.10 (95% CI: 0.98 to 1.23), and 1.02 (95% CI: 0.99 to 1.05) for extent of CAL, mean CAL, and the number of missing teeth, respectively. Findings did not indicate additive interaction of periodontal destruction and diabetes regarding all-cause and CVD mortality. Similarly, no substantial evidence was found to demonstrate the presence of multiplicative interaction or mediation. Besides adjustment for baseline covariates, time-varying covariates were also considered and led to comparable results. In summary, despite their reciprocal relationship, periodontal destruction and diabetes may be independent risk factors for all-cause and CVD mortality.

Advanced brain aging: relationship with epidemiologic and genetic risk factors, and overlap with Alzheimer disease atrophy patterns.

We systematically compared structural imaging patterns of advanced brain aging (ABA) in the general-population, herein defined as significant deviation from typical BA to those found in Alzheimer disease (AD). The hypothesis that ABA would show different patterns of structural change compared with those found in AD was tested via advanced pattern analysis methods. In particular, magnetic resonance images of 2705 participants from the Study of Health in Pomerania (aged 20-90 years) were analyzed using an index that captures aging atrophy patterns (Spatial Pattern of Atrophy for Recognition of BA (SPARE-BA)), and an index previously shown to capture atrophy patterns found in clinical AD (Spatial Patterns of Abnormality for Recognition of Early Alzheimer's Disease (SPARE-AD)). We studied the association between these indices and risk factors, including an AD polygenic risk score. Finally, we compared the ABA-associated atrophy with typical AD-like patterns. We observed that SPARE-BA had significant association with: smoking (P<0.05), anti-hypertensive (P<0.05), anti-diabetic drug use (men P<0.05, women P=0.06) and waist circumference for the male cohort (P<0.05), after adjusting for age. Subjects with ABA had spatially extensive gray matter loss in the frontal, parietal and temporal lobes (false-discovery-rate-corrected q<0.001). ABA patterns of atrophy were partially overlapping with, but notably deviating from those typically found in AD. Subjects with ABA had higher SPARE-AD values; largely due to the partial spatial overlap of associated patterns in temporal regions. The AD polygenic risk score was significantly associated with SPARE-AD but not with SPARE-BA. Our findings suggest that ABA is likely characterized by pathophysiologic mechanisms that are distinct from, or only partially overlapping with those of AD.

Gene transcripts associated with muscle strength: a CHARGE meta-analysis of 7,781 persons.

Lower muscle strength in midlife predicts disability and mortality in later life. Blood-borne factors, including growth differentiation factor 11 (GDF11), have been linked to muscle regeneration in animal models. We aimed to identify gene transcripts associated with muscle strength in adults. Meta-analysis of whole blood gene expression (overall 17,534 unique genes measured by microarray) and hand-grip strength in four independent cohorts (n = 7,781, ages: 20-104 yr, weighted mean = 56), adjusted for age, sex, height, weight, and leukocyte subtypes. Separate analyses were performed in subsets (older/younger than 60, men/women). Expression levels of 221 genes were associated with strength after adjustment for cofactors and for multiple statistical testing, including ALAS2 (rate-limiting enzyme in heme synthesis), PRF1 (perforin, a cytotoxic protein associated with inflammation), IGF1R, and IGF2BP2 (both insulin like growth factor related). We identified statistical enrichment for hemoglobin biosynthesis, innate immune activation, and the stress response. Ten genes were associated only in younger individuals, four in men only and one in women only. For example, PIK3R2 (a negative regulator of PI3K/AKT growth pathway) was negatively associated with muscle strength in younger (<60 yr) individuals but not older (≥ 60 yr). We also show that 115 genes (52%) have not previously been linked to muscle in NCBI PubMed abstracts. This first large-scale transcriptome study of muscle strength in human adults confirmed associations with known pathways and provides new evidence for over half of the genes identified. There may be age- and sex-specific gene expression signatures in blood for muscle strength.

Novel loci associated with usual sleep duration: the CHARGE Consortium Genome-Wide Association Study.

Usual sleep duration is a heritable trait correlated with psychiatric morbidity, cardiometabolic disease and mortality, although little is known about the genetic variants influencing this trait. A genome-wide association study (GWAS) of usual sleep duration was conducted using 18 population-based cohorts totaling 47 180 individuals of European ancestry. Genome-wide significant association was identified at two loci. The strongest is located on chromosome 2, in an intergenic region 35- to 80-kb upstream from the thyroid-specific transcription factor PAX8 (lowest P=1.1 × 10(-9)). This finding was replicated in an African-American sample of 4771 individuals (lowest P=9.3 × 10(-4)). The strongest combined association was at rs1823125 (P=1.5 × 10(-10), minor allele frequency 0.26 in the discovery sample, 0.12 in the replication sample), with each copy of the minor allele associated with a sleep duration 3.1 min longer per night. The alleles associated with longer sleep duration were associated in previous GWAS with a more favorable metabolic profile and a lower risk of attention deficit hyperactivity disorder. Understanding the mechanisms underlying these associations may help elucidate biological mechanisms influencing sleep duration and its association with psychiatric, metabolic and cardiovascular disease.

Genetic, psychosocial and clinical factors associated with hippocampal volume in the general population.

The hippocampus--crucial for memory formation, recall and mood regulation--is involved in the pathophysiology of dementia and depressive disorders. Recent genome-wide association studies (GWAS) have identified five genetic loci associated with hippocampal volume (HV). Previous studies have described psychosocial and clinical factors (for example, smoking, type 2 diabetes and hypertension) to have an impact on HV. However, the interplay between genetic, psychosocial and clinical factors on the HV remains unclear. Still, it is likely that genetic variants and clinical or psychosocial factors jointly act in modifying HV; it might be possible they even interact. Knowledge of these factors might help to quantify ones individual risk of or rather resilience against HV loss. We investigated subjects (N=2463; 55.7% women; mean age 53 years) from the Study of Health in Pomerania (SHIP-2; SHIP-TREND-0) who underwent whole-body magnetic resonance imaging (MRI) and genotyping. HVs were estimated with FreeSurfer. For optimal nonlinear model fitting, we used regression analyses with restricted cubic splines. Genetic variants and associated psychosocial or clinical factors were jointly assessed for potential two-way interactions. We observed associations between HV and gender (P<0.0001), age (P<0.0001), body height (P<0.0001), education (P=0.0053), smoking (P=0.0058), diastolic blood pressure (P=0.0211), rs7294919 (P=0.0065), rs17178006 (P=0.0002), rs6581612 (P=0.0036), rs6741949 (P=0.0112) and rs7852872 (P=0.0451). In addition, we found three significant interactions: between rs7294919 and smoking (P=0.0473), rs7294919 and diastolic blood pressure (P=0.0447) and between rs7852872 and rs6581612 (P=0.0114). We suggest that these factors might have a role in the individual susceptibility to hippocampus-associated disorders.

IGF-I levels and depressive disorders: results from the Study of Health in Pomerania (SHIP).

In vitro and in vivo models revealed that the somatotropic system exerts central effects on the central nervous system. Disturbances to this system such as in the case of growth hormone deficiency or growth hormone excess, are associated with a wide range of psychiatric disorders. Nonetheless, there is no epidemiological data available regarding the influence of growth hormone and its mediator, insulin-like growth factor I (IGF-I), on depressive disorders. The objective of this study was to investigate whether endogenous IGF-I levels may predict depression in humans. We included 4079 adult subjects from the Study of Health in Pomerania (SHIP), a population-based study with a 5-year follow-up period. The main predictor was the baseline IGF-I value categorized in three levels as <10th percentile, between the 10th and the 90th percentile (the reference group) and >90th percentile. The outcome measure was the incidence of depressive disorders according to the Composite International Diagnostic-Screener (CID-S). After adjustment for potential confounding variables, females with IGF-I levels below the 10th percentile had a higher incidence of depressive disorders during follow-up (OR 2.70 95% CI 1.38-5.28, p=0.004) compared to females within the reference group (10th-90th percentile). Among males, those with IGF-I levels above the 90th percentile had a higher risk of depressive disorder (OR 3.26 95% CI 1.52-6.98, p=0.002) than those within the 10th-90th percentile. In conclusion we can demonstrate that low IGF-I levels in females and high IGF-I levels in males predict the development of depressive disorders in this general adult population sample.

Mendelian randomization suggests non-causal associations of testosterone with cardiometabolic risk factors and mortality.

Prospective studies showed that low serum testosterone concentrations are associated with various cardiometabolic risk factors and mortality. However, the causal nature of these associations is controversial. We studied 1 882 men aged 20-79 years with serum testosterone concentrations and genotyping data from the longitudinal population-based Study of Health in Pomerania. Testosterone concentrations were cross-sectionally associated with cardiometabolic risk factors, including anthropometric, lipid, blood pressure and glycaemic parameters; and prospectively with all-cause mortality (277 deaths, 14.7%) during the 10-year follow-up. To overcome problems of residual confounding, reverse causation, or regression dilution bias in the investigated testosterone-outcome associations, we used two-stage least square regression models with previously identified polymorphisms at the SHBG gene (rs12150660) and X chromosome (rs5934505) as multiple genetic instruments in an instrumental variable (IV) approach, also known as Mendelian randomization. In standard regression analyses, testosterone was robustly associated with a wide range of cardiometabolic risk factors. In subsequent IV analyses, no such significant associations were observed. Similarly, prospective analyses showed a consistent association of low testosterone concentrations with increased all-cause mortality risk, which was not apparent in subsequent IV analyses. The present Mendelian randomization analyses did not detect any evidence for causal associations of testosterone concentrations with cardiometabolic risk factors and mortality, suggesting that previously reported associations might largely result from residual confounding or reverse causation. Although testosterone assessment might improve risk prediction, implementation of testosterone replacement therapy requires further evidence of a direct effect on cardiometabolic outcomes from double-blinded randomized controlled trials and large-scale Mendelian randomization meta-analyses.

Screening for primary aldosteronism in hypertensive subjects: results from two German epidemiological studies.

OBJECTIVE: The prevalence of primary aldosteronism in unselected hypertensive patients is currently unknown. We investigated the frequency of positive screening results for primary aldosteronism based on the aldosterone-to-renin ratio (ARR) in hypertensive subjects aged 30-79 years from two German epidemiological studies. We further examined the frequency of positive screening results in subjects with resistant hypertension or stage III hypertension and assessed possible disparities between untreated and treated hypertensive subjects. METHODS: Data were obtained from the first follow-ups of the population-based study of health in Pomerania (SHIP; n=1392) and the cooperative health research in the region of Augsburg (KORA; n=1052). Study-specific reference ranges for plasma aldosterone concentration (PAC), plasma renin concentration (PRC) and the ARR were applied. Confirmation tests for primary aldosteronism were not performed in these epidemiological studies.Three definitions for a positive screening for primary aldosteronism were applied: A) increased ARR; B) increased ARR and decreased PRC; and C) increased ARR and increased PAC and decreased PRC. RESULTS: The frequency of positive screening results was 7.0, 3.8 and 0.2% according to definitions A-C respectively. In the subgroups of subjects with resistant hypertension (11.9, 5.5 and 0.9%) or stage III hypertension (18.3, 14.0 and 1.1%), these frequencies were markedly higher than those in the general hypertensive population. There was no difference in the frequency of positive screening results between the treated and untreated hypertensive subjects. CONCLUSIONS: A maximum of 7.0% of the hypertensive population in Germany shows a positive screening result for primary aldosteronism. Thus, primary aldosteronism may be less frequent than previously expected based on data from referred hypertensive patients.

The effect of catechol-O-methyltransferase polymorphisms on pain is modified by depressive symptoms.

BACKGROUND: Variations within the catechol-O-methyltransferase (COMT) gene have been associated with pain severity in temporomandibular disorders (TMDs). Psychological factors such as personal conflicts, life stress and depression, are well known to be associated with onset, severity and chronicity of pain disorders. AIM: We hypothesized that the relationship between the COMT gene and TMD pain is modified by depressive symptoms. METHODS: Cross-sectional data from the population-based Study of Health in Pomerania (SHIP) in Germany were used to estimate additive interactions between depressive symptoms and 22 single-nucleotide polymorphisms (SNPs) of the COMT gene and the neighbouring thioredoxin reductase 2 (TXNRD2) gene on TMD pain. All participants were Caucasian subjects from a rural area in Northeast Germany. After exclusion of 79 subjects with antidepressant medication, 29.9% of the remaining 3904 subjects reported lifetime depressive symptoms. TMD pain was assessed by a standardized clinical examination. Among various TMD signs, only those that assessed muscle or joint pain on palpation were used as recommended. RESULTS: Six SNPs from the first of three COMT/TXNRD2 haploblocks interacted with depressive symptoms on TMD pain (smallest p-value: 2.7 × 10(-10) ). In subjects without depressive symptoms, rs5993882 was identified as the SNP most likely to be related to TMD pain. In subjects with symptoms of depression, rs1544325 was the corresponding top COMT SNP. CONCLUSIONS: Our results indicate that variants within the COMT gene are associated with pain perception. However, this association is highly moderated by the absence or presence of lifetime depressive symptoms.

Genome-wide association analysis of coffee drinking suggests association with CYP1A1/CYP1A2 and NRCAM.

Coffee consumption is a model for addictive behavior. We performed a meta-analysis of genome-wide association studies (GWASs) on coffee intake from 8 Caucasian cohorts (N=18 176) and sought replication of our top findings in a further 7929 individuals. We also performed a gene expression analysis treating different cell lines with caffeine. Genome-wide significant association was observed for two single-nucleotide polymorphisms (SNPs) in the 15q24 region. The two SNPs rs2470893 and rs2472297 (P-values=1.6 × 10(-11) and 2.7 × 10(-11)), which were also in strong linkage disequilibrium (r(2)=0.7) with each other, lie in the 23-kb long commonly shared 5' flanking region between CYP1A1 and CYP1A2 genes. CYP1A1 was found to be downregulated in lymphoblastoid cell lines treated with caffeine. CYP1A1 is known to metabolize polycyclic aromatic hydrocarbons, which are important constituents of coffee, whereas CYP1A2 is involved in the primary metabolism of caffeine. Significant evidence of association was also detected at rs382140 (P-value=3.9 × 10(-09)) near NRCAM-a gene implicated in vulnerability to addiction, and at another independent hit rs6495122 (P-value=7.1 × 10(-09))-an SNP associated with blood pressure-in the 15q24 region near the gene ULK3, in the meta-analysis of discovery and replication cohorts. Our results from GWASs and expression analysis also strongly implicate CAB39L in coffee drinking. Pathway analysis of differentially expressed genes revealed significantly enriched ubiquitin proteasome (P-value=2.2 × 10(-05)) and Parkinson's disease pathways (P-value=3.6 × 10(-05)).

Whole-body magnetic resonance imaging of healthy volunteers: pilot study results from the population-based SHIP study.

PURPOSE: Approximately 4000 volunteers will undergo whole-body magnetic resonance imaging (WB-MRI) within the next 3 years in the population-based Study of Health in Pomerania (SHIP). Here we present a pilot study conducted (a) to determine the feasibility of adding a WB-MRI protocol to a large-scale population-based study, (b) to evaluate the reliability of standardized MRI interpretation, and (c) to establish an approach for handling pathological findings. MATERIALS AND METHODS: The institutional review board approved the study, and oral and written informed consent was obtained from each participant. Two hundred healthy volunteers (99 women, 101 men; mean age 48.3 years) underwent a standardized WB-MRI protocol. The protocol was supplemented by contrast-enhanced cardiac MRI and magnetic resonance (MR) angiography in 61 men (60.4%) and cardiac MRI and MR mammography in 44 women (44.4%). MR scans were evaluated independently by two readers. Abnormalities were discussed by an advisory board and classified according to the need for further clinical work-up. RESULTS: One hundred ninety-four (97.0%) WB-MRI examinations were successfully completed in a mean scan time per subject of 90 minutes. There were 431 pathological findings in 176 (88%) of the participants. Of those 45 (10.4%) required further clinical work-up and 386 (89.6%) characterized as benign lesions did not. The interobserver agreement for the detection of pathological findings was excellent (kappa = 0.799). CONCLUSION: The preliminary results presented here indicate that a large prospective, population-based study using WB-MRI is feasible and that the results of image analysis are reproducible. A variety of positive findings provide valuable information regarding disease prevalence in a general adult population.

A 3-year clinical and radiographic study of implants placed simultaneously with maxillary sinus floor augmentations using a new nanocrystalline hydroxyapatite.

The aims of this case series was to evaluate the success rate of implants and their restorations, the sinus bone graft resorption, and the marginal bone loss around the implants when nanocristalline HA embedded in a silica matrix was exclusively used as grafting material. In 13 partially edentulous patients of a private practice having missing teeth in the posterior maxilla and a subantral bone height between 3 and 7 mm, 19 sinus augmentations (100% Nanobone, Artoss, Rostock, Germany) by the lateral lift technique were performed. The implants (Tiolox/Tiologic Implants, Dentaurum, Ispringen, Germany) were simultaneously placed. After 6 to 9 months 37 implants were restored with fixed dental prostheses. The clinical evaluation included peri-implant parameters, periotest measurements and the restorations. The radiographic bone heights over time were estimated with linear mixed models. The implant success rate was 100% after three years. The periotest values (between -7 and -6) after implant abutment connection indicated a solid osseointegration. The mean rates of the marginal bone loss over the first year were higher (mesial: -0.55, distal: -0.51 mm) than the annual rates thereafter (mesial: -0.09 mm, distal: -0.08 mm). The mean rates of changes in the total bone height were neglectable (<0.2 mm) and not significant. The prosthodontic and esthetic evaluation revealed a successful outcome. Within the limits of this clinical report it may be concluded that maxillary sinus augmentation using 100% nanocristalline HA embedded in a silica matrix to support implants is a reliable procedure.

The factors associated with body mass index in adults from the study of health in Pomerania (SHIP-0), Germany.

OBJECTIVE: To investigate the relation between dental status, BMI and systemic diseases and to evaluate the risk factors for having a higher BMI. MATERIALS AND METHODS: Apopulation based cross sectional study of 6248 subjects aged 18-80 years (response of 68.8%, n=4310) was conducted in the Study of Health in Pomerania (SHIP-0). Socio-demographic, medical and oral health information was recorded by 5 dentists at two similarly equipped medical/dental services in the cities of Greifswald and Stralsund. Bivariate statistics, multivariate statistics, linear and logistic regression models were performed to assess the relationship between following covariates: gender, educational level, family status, social activities, income, quality of life (SF-12), smoking, alcohol abuse, diabetes, renal disease, high blood pressure, dental status and high physical activity. RESULTS: Significant risk factors for subjects having a higher BMI were: high blood pressure (OR=2.28), diabetes (OR=2.10), educational level (low: OR=1.49; medium OR=1.27), male (OR=1.32) and former smoker (OR=1.20). whereas young age, being single and being dentate (natural teeth, replaced teeth or fixed teeth) was shown to be protective for having a "high" BMI. CONCLUSION: The most important predictors of BMI were shown to be social and medical factors. Dental factors are most significantly influenced by social factors and also exhibit an important impact on BMI.

Dental nomograms for benchmarking based on the study of health in Pomerania data set.

AIM: Benchmarking is a means of setting goals or targets. On an oral health level, it denotes retaining more teeth and/or improving the quality of life. The goal of this pilot investigation was to assess whether the data generated by a population-based study (SHIP 0) can be used as a benchmark data set to characterize different practice profiles. MATERIAL AND METHODS: The data collected in the population-based study SHIP (n=4310) in eastern Germany were used to generate nomograms of tooth loss, attachment loss, and probing depth. The nomograms included twelve 5-year age strata (20-79 years) presented as quartiles, and additional percentiles of the dental parameters for each age group. Cross-sectional data from a conventional dental office (n=186) and from a periodontology unit (n=130, Greifswald) in the study region as well as longitudinal data set of a another periodontology unit (n=135, Kiel) were utilized in order to verify whether the given practice profile was accurately reflected by the nomogram. RESULTS: In terms of tooth loss, the data from the conventional dental office agree with the median from the nomogram. For attachment loss and probing depth, some age groups yielded slight but not uniform deviations from the median. Cross-sectional data from the periodontology unit Greifswald showed attachment loss higher than the median in younger but not in older age groups. The probing depth was uniformly less than the median and tended toward the 25th percentile with increasing age. The longitudinal data of the Unit of Periodontology in Kiel showed a pronounced trend towards higher percentiles of residual teeth, meaning that the patients retained more teeth. CONCLUSION: The profile of the Pomeranian dental office does not deviate noticeably from the population-based nomograms. The higher attachment loss of the Unit of Periodontology in Greifswald in younger age strata clearly reflects their selection because of periodontal disease; the combination of higher attachment loss and decreased probing depth may reflect the success of the treatment. The tendency of attachment loss towards the median with increasing age may indicate that the Unit of Periodontology in Greifswald does not fulfill its function as a special care unit in the older subjects. The longitudinal data set of the Unit of Periodontology in Kiel impressively reflects the potential of population-based data sets as a means for benchmarking. Thus, nomograms can help to determine the practice profile, potentially yielding benefits for the dentist, health insurance company, or--as in the case of the special care unit--public health research.

Hydrothermal ceramic for porcelain-fused-to-metal crowns: an initial experience report from clinical practice.

The development of hydrothermal ceramics was an important requirement for fusing hydrolysis-resistant ceramics to precious metal alloys with low melting interval. Clinical findings since 1992 confirm the wide range of application of these metal-ceramic restorations in dentistry. Initial problems concerning temperature regulation of the ceramic ovens were rectified by checking and adjusting them for lower sintering temperatures. The golden yellow color is only one advantage of the ceramic-veneered alloy. Other advantages include its nonporous, smooth surface, translucence, and suitability for use in all types of dental restorations and reconstructions. Hydrothermal ceramic veneers thus can help to substantially reduce the number of different alloys used in a patient's mouth.