Peter Meisel

Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log10 reduction factor of 1.5, the log10 reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

Genome‐wide association study of chronic periodontitis in a general German population

AIM To identify loci associated with chronic periodontitis through a genome-wide association study (GWAS). MATERIALS AND METHODS A GWAS was performed in 4032 individuals of two independent cross-sectional studies of West Pomerania (SHIP n = 3365 and SHIP-TREND n = 667) with different periodontal case definitions. Samples were genotyped with the Affymetrix Genome-Wide Human SNP Array 6.0 or the Illumina Human Omni 2.5 array. Imputation of the HapMap as well as the 1000 Genome-based autosomal and X-chromosomal genotypes and short insertions and deletions (INDELs) was performed in both cohorts. Finally, more than 17 million SNPs and short INDELs were analysed. RESULTS No genome-wide significant associations were found for any periodontitis case definition, regardless of whether individuals aged >60 years where excluded or not. Despite no single SNP association reached genome-wide significance, the proportion of variance explained by additive effects of all common SNPs was around 23% for mean proximal attachment loss. Excluding subjects aged >60 years increased the explained variance to 34%. CONCLUSIONS No single SNPs were found to be genome-wide significantly associated with chronic periodontitis in this study.

Women are periodontally healthier than men, but why don't they have more teeth than men?

Objective: Periodontal diseases are more prevalent in men than in women. However, in a population-based epidemiological study, we found that, on average, women have fewer teeth than men. The aim of this study was to test different hypotheses that could explain this obvious paradox. Design: In 4,290 randomly selected participants from the normal population (Study of Health in Pomerania), we determined diagnostic periodontal parameters, attachment loss, and number of teeth. Behavioral and environmental risk factors were assessed by interviews and questionnaires. Use of estrogens was assessed, and urinary excretion of collagen cross-links was determined. Results: Multiple regression analyses adjusted for caries and periodontitis revealed that in the women of this population, there is an inverse association between the number of children born and the number of teeth (P < 0.01). This relationship depends on socioeconomic status, bone metabolism, and the use of estrogens. In the group of the youngest (20-40 years), the bone turnover rate is positively related to the number of children born (P < 0.01). In postmenopausal women treated with estrogens, the number of teeth was higher than in men of the same age group. Only in women without hormone treatment were there fewer teeth. Conclusion: The apparent paradox of having fewer teeth despite better periodontal health in women compared with men is related to an increased bone turnover rate and socioeconomic conditions such as low education and low social status. Periodontal health is even worse if these factors are combined.

Replication of the association of chromosomal region 9p21.3 with generalized aggressive periodontitis (gAgP) using an independent case-control cohort

BackgroundThe human chromosomal region 9p21.3 has been shown to be strongly associated with Coronary Heart Disease (CHD) in several Genome-wide Association Studies (GWAS). Recently, this region has also been shown to be associated with Aggressive Periodontitis (AgP), strengthening the hypothesis that the established epidemiological association between periodontitis and CHD is caused by a shared genetic background, in addition to common environmental and behavioural risk factors. However, the size of the analyzed cohorts in this primary analysis was small compared to other association studies on complex diseases. Using our own AgP cohort, we attempted to confirm the described associations for the chromosomal region 9p21.3.MethodsWe analyzed our cohort consisting of patients suffering from the most severe form of AgP, generalized AgP (gAgP) (n = 130) and appropriate periodontally healthy control individuals (n = 339) by genotyping four tagging SNPs (rs2891168, rs1333042, rs1333048 and rs496892), located in the chromosomal region 9p21.3, that have been associated with AgP.ResultsThe results confirmed significant associations between three of the four SNPs and gAgP. The combination of our results with those from the study which described this association for the first time in a meta-analysis of the four tagging SNPs produced clearly lower p-values compared with the results of each individual study. According to these results, the most plausible genetic model for the association of all four tested SNPs with gAgP seems to be the multiplicative one.ConclusionWe positively replicated the finding of an association between the chromosomal region 9p21.3 and gAgP. This result strengthens support for the hypothesis that shared susceptibility genes within this chromosomal locus might be involved in the pathogenesis of both CHD and gAgP.

MDR1 gene polymorphisms and risk of gingival hyperplasia induced by calcium antagonists.

Gingival overgrowth is a common side effect of calcium antagonists. Although the pathogenesis is unknown, several lines of evidence point to a modulation of inflammatory processes. Because the calcium antagonists, albeit to a variable degree, act as inhibitors of P‐glycoprotein (P‐gp), the gene product of multidrug resistance 1 (MDR1), and inflammation may modify P‐gp expression, we analyzed the MDR1 polymorphisms as risk factors for gingival overgrowth induced by calcium antagonists.

Total tooth loss and systemic correlates of inflammation: role of obesity.

Obesity and edentulism are both associated with multiple systemic disorders with an inflammatory background including periodontal diseases. This study aimed to evaluate the different impact of obesity on inflammation in dentate and toothless subjects. The data came from the population‐based, cross‐sectional study SHIP (Study of Health in Pomerania). We determined anthropometric measures including BMI, waist‐to‐hip ratio (WHR), diagnostic periodontal parameters, and systemic metabolites. It was shown that measures of systemic markers of inflammation and lipid or glucose metabolism (P < 0.001) were increased with higher WHR. When adjusted for age, sex, smoking, diabetes, education, physical activity, and last dentists appointment, C‐reactive protein (CRP), fibrinogen, and leukocyte count were significantly related to WHR increasing from the first to the fourth WHR quartile (P < 0.001) as well as to the BMI. In both dentate and edentulous subjects higher WHR contributes significantly to increasing systemic CRP and fibrinogen with sex differences. In toothless subjects, while still dependent on increasing WHR, the inflammatory markers CRP and fibrinogen were higher than in dentate subjects, thereby revealing effect modification between sex and edentulism (P < 0.010). In conclusion, subjects with total tooth loss, although devoid of periodontal inflammation, may exhibit increased levels of systemic inflammatory mediators. Possible implications are discussed with respect to obesity and its relationship to inflammation.

Tooth Loss, Periodontitis, and Statins in a Population-Based Follow-Up Study

BACKGROUND Statins, frequently prescribed in lipid-lowering therapies, seem to have additional beneficial effects on periodontitis and tooth loss. If this is true, then chronic treatment with statins should also result in diminished tooth loss as a long-term response. METHODS A 5-year population-based follow-up study of tooth loss was performed comparing participants treated with statins (n = 134) with those not on the drugs (Study of Health in Pomerania). Negative binomial regression models were used to analyze the count variable of the outcome, including risk factors for tooth loss and measures of cholesterol metabolism. RESULTS When adjusted for age and sex, statins were associated with reduced tooth loss during the follow-up period (incidence risk ratio [IRR] = 0.70, 95% confidence interval [CI] = 0.50 to 0.99, P = 0.04). When additionally adjusted for risk factors of periodontal breakdown, IRR was 0.72 (95% CI = 0.52 to 1.01). There was significant interaction with low-density lipoprotein cholesterol (LDL-c) at baseline. After stratification by LDL-c, statins were associated with reduced tooth loss, resulting in IRR = 0.89 (95% CI = 0.44 to 1.83) and 0.64 (95% CI = 0.43 to 0.95), P = 0.03, at LDL-c concentrations ≤100 mg/dL and >100 mg/dL (2.58 mmol/L), respectively. The data also showed reduced tooth loss associated with the 5-year reduction in LDL-c levels on a mmol/L basis and independently of statins (IRR = 0.87, 95% CI = 0.80 to 0.96, P = 0.004). CONCLUSION Long-term treatment with systemically administered statins may have the beneficial effect of protecting against tooth loss.

Association of periodontitis with the risk of oral leukoplakia

BACKGROUND Oral leukoplakia is an oral lesion suspected to be of premalignant character. Besides smoking and alcohol, the risk factors for the development of this oral lesion are still less identified. The purpose of this study was the search for a possible influence of periodontitis on the risk of leukoplakia. METHODS We used data from 4233 subjects (2116 women and 2117 men) who were recruited for the population-based Study of Health in Pomerania (SHIP) and finished a standard medical and dental examination. One hundred two-three cases with oral leukoplakia were 1:2 age and sex-matched with 246 healthy control subjects. Measures of bleeding on probing and clinical attachment loss were related to oral leukoplakia. RESULTS We found increased periodontal measures in subjects with leukoplakia. Adjusting for risk factors and possible confounders revealed a periodontitis-related dose-dependent increase in the probability of having oral leukoplakia. Odds ratios adjusted for socioeconomic factors and smoking computed for the second, third and fourth quartiles of clinical attachment loss were OR=1.7 (0.6-5.0), 3.3 (0.8-13.1) and 5.3 (1.2-22.7), respectively. For bleeding on probing the respective odds ratios were OR=2.0 (0.8-4.90), 2.9 (1.1-7.8) and 3.8 (1.5-9.8), respectively. Measures of systemic inflammation and of lipid metabolism were important cofactors attenuating these figures. While smoking is a risk factor of leukoplakia, oral hygiene is protective. In a follow-up survey, the leukoplakia subjects had lost more teeth than their counterparts (p=0.043). CONCLUSION Periodontitis increases the risk of oral leukoplakia and, therefore, the risk of mucosal lesions predisposing to oral cancers.

Prediction of periodontal disease: modelling and validation in different general German populations

AIM To develop models for periodontitis using self-reported questions and to validate them externally. METHODS The Study of Health in Pomerania (SHIP-0) was used for model development. Periodontitis was defined according to the definitions of the Center for Disease Control and Prevention-American Academy of Periodontology, the 5th European Workshop in Periodontology, and Dietrich et al. (≥2 teeth with inter-proximal clinical attachment loss of ≥4 mm and 6 mm as moderate and severe periodontitis) respectively. These models were validated in SHIP-Trend and the Fourth German Oral Health Study (DMS IV). RESULTS Final models included age, gender, education, smoking, bleeding on brushing and self-reported presence of mobile teeth. Concordance-statistics (C-statistics) of the final models from SHIP-0 were 0.84, 0.82 and 0.85 for the three definitions respectively. Validation in SHIP-Trend revealed C-statistics of 0.82, 0.81 and 0.82 respectively. As bleeding on brushing and presence of mobile teeth were unavailable in DMS IV, reduced models were developed. C-statistics of reduced models were 0.82, 0.81 and 0.83 respectively. Validation in DMS IV revealed C-statistics of 0.72, 0.78 and 0.72 for the three definitions respectively. All p values of the goodness-of-fit tests were >0.05. CONCLUSIONS The models yielded a moderate usefulness for prediction of periodontitis.

Refining definitions of periodontal disease and caries for prediction models of incident tooth loss

AIM To assess the suitability of different definitions of caries and periodontitis for inclusion in tooth loss prediction models. MATERIALS AND METHODS The Study of Health in Pomerania (SHIP) is a population-based cohort study conducted in 1997-2001 (SHIP-0) and 2002-2006 (SHIP-1). This sample comprised 2,780 subjects aged 20-81 years with complete information on dental and periodontal status [DMFS status, clinical attachment loss (CAL) and probing depth (PD)]. Analyses on five-year tooth loss were limited to half-mouth data. RESULTS The predictive value of tested definitions was markedly age- and gender-dependent: in 20-39-aged men, the number of decayed or filled surfaces best predicted the number of lost teeth, whereas in young women CAL≥4 mm performed best. In older subjects, periodontal definitions were superior to caries definitions: mean CAL performed best in 40-59-year olds, whereas AL- or PD-related definitions predicted best in 60-81-year olds. On tooth level, mean CAL was the superior definition to assess 5-year incident tooth loss in all strata except for young men. CONCLUSIONS Caries parameters best predicted incident tooth loss in men aged 20-39 years; in the intermediate and oldest age group and in young women, mean AL was most informative. Therefore, prediction models need to be developed for different age and gender groups.