Exome Sequencing of 5 Families with Severe Early-Onset Periodontitis.

Periodontitis is characterized by alveolar bone loss leading to tooth loss. A small proportion of patients develop severe periodontitis at the juvenile or adolescent age without exposure to the main risk factors of the disease. It is considered that these cases carry rare variants with large causal effects, but the specific variants are largely unknown. In this study, we performed exome sequencing of 5 families with children who developed stage IV, grade C, periodontitis between 3 and 18 y of age. In 1 family, we found compound heterozygous variants in the gene CTSC (p.R272H, p.G139R), 1 of which was previously identified in a family with prepubertal periodontitis. Subsequent targeted resequencing of the CTSC gene in 24 patients <25 y of age (stage IV, grade C) identified the known mutation p.I453V (odds ratio = 4.06, 95% CI = 1.6 to 10.3, P = 0.001), which was previously reported to increase the risk for adolescent periodontitis. An affected sibling of another family carried a homozygous deleterious mutation in the gene TUT7 (p.R560Q, CADD score >30 [Combined Annotation Dependent Depletion]), which is implicated in regulation of interleukin 6 expression. Two other affected siblings shared heterozygous deleterious mutations in the interacting genes PADI1 and FLG (both CADD = 36), which contribute to the integrity of the environment-tissue barrier interface. Additionally, we found predicted deleterious mutations in the periodontitis risk genes ABCA1, GLT6D1, and SIGLEC5. We conclude that the CTSC variants p.R272H and p.I453V have different expressivity and diagnostic relevance for prepubertal and adolescent periodontitis, respectively. We propose additional causal variants for early-onset periodontitis, which also locate within genes that carry known susceptibility variants for common forms. However, the genetic architecture of juvenile periodontitis is complex and differs among the affected siblings of the sequenced families.

Smoking Modifies the Genetic Risk for Early-Onset Periodontitis.

Periodontitis has low-prevalence, highly severe disease manifestations with an early onset and rapid progression. The diagnosis is based on severe destruction of the alveolar bone in adolescents and young adults. Genetic susceptibility variants and smoking are well-established risk factors, but their interactions in modifying disease susceptibility have not been studied. We aimed to identify genetic risk variants of early-onset periodontitis that unmask their effects on tobacco smoke exposure. To this end, we analyzed 79,780,573 common variants in 741 northwest Europeans diagnosed to have >30% bone loss at >2 teeth before 35 y of age, using imputed genotypes of the OmniExpress BeadChip. Never versus ever smokers were compared in a logistic regression analysis via a case-only approach. To explore the effect of tobacco smoke on the expression of the G×S-associated genes, cultures of primary gingival fibroblasts (n = 9) were exposed to cigarette smoke extract, and transcripts were quantified by reverse transcription polymerase chain reaction. We identified 16 loci for which our analysis suggested an association with G×S increased disease risk (P < 5 × 10-5). Nine loci had previously been reported to be associated with spirometric measures of pulmonary function by an earlier G×S genome-wide association study. Genome-wide significant cis expression quantitative trait loci were reported for G×S-associated single-nucleotide polymorphisms at ST8SIA1 and SOST, indicating a causal role of these genes in tobacco-related etiopathology. Notably, SOST is a negative regulator of bone growth, and ST8SIA1 has a role in tissue remodeling. Cigarette smoke extract significantly altered the expression of 2 associated genes: SSH1 (P = 5 × 10-07), which is required for NF-κB activation and innate immune responses to bacterial invasion, and ST8SIA1 (P = 0.0048). We conclude that the genetic predisposition to early-onset periodontitis is in part triggered by smoking and that tobacco smoke directly affects the expression of genes involved in bone homeostasis, tissue repair, and immune response.

Expression of antimicrobial peptides and interleukin-8 during early stages of inflammation: An experimental gingivitis study.

BACKGROUND AND OBJECTIVES: In the oral cavity, the epithelial surface is constantly exposed to a number of different microorganisms that are organized in a well-structured biofilm. The aim of this study was to monitor gingival expression of antimicrobial peptides (AMPs) and interleukin-8 (IL-8) in an early gingivitis model. MATERIAL AND METHODS: Experimental gingivitis was allowed to develop in healthy volunteers (n = 17). Bleeding on probing (BOP%) and gingival crevicular fluid volume (GCF) were assessed at baseline and day 1, 3, 5, 7 and 14. Expression of AMPs (human beta-defensin-2, hBD-2; CC-chemokine ligand 20, CCL20; psoriasin, pso/S100A7) and IL-8 was analyzed by immunohistochemistry in gingival biopsies. In addition, hBD-2 and IL-8 protein expression was monitored in GCF using the ELISA technology. RESULTS: Experimental gingivitis gradually developed with an increase in BOP scores and GCF volume over time. In GCF, elevated concentrations of hBD-2 and IL-8 were monitored at day 1, 5 and 7 (p ≤ 0.0002). Immunohistochemical analysis of gingival sections demonstrated increased staining for hBD-2 at day 3, whereas the CCL20, pso/S100A7, and IL-8 expression was increased at later time points (p < 0.05). CONCLUSION: For the first time, this study showed the time-dependent regulation of AMPs, following clinical signs of experimentally induced gingival inflammation. Differential temporal expression for AMPs may ensure a constant antimicrobial activity against changes in the bacterial composition of the growing dental biofilm.

Influence of fruit consumption and fluoride application on the prevalence of caries and erosion in vegetarians--a controlled clinical trial.

BACKGROUND/OBJECTIVES: Caries and erosion are common diseases of the dental hard tissues. The influence of vegetarianism on the development of caries and erosion has scarcely been investigated in the past. The aim of the present study was to evaluate the influence of fruit consumption and topical fluoride application on the prevalence of caries and erosion in vegetarians. SUBJECTS/METHODS: In 100 vegetarians and 100 nonvegetarians, a dental examination was performed. The indices for decayed, missing, filled teeth (DMFT) and surfaces (DMFS) were determined. DMFT and DMFS were subdivided into decayed teeth (DT), filled teeth (FT), decayed surfaces (DS) and filled surfaces (FS). In addition, the hygiene index and the number of teeth with dental erosion (DE), root caries (RC) and overhanging restoration margins (ORM) were recorded. A questionnaire assessed patients' eating habits, frequency of oral hygiene, dentist visits and topical fluoride application. For statistical analysis, unpaired t-test, Mann-Whitney test and Pearson's chi-square test were applied. RESULTS: Vegetarians had significantly more DT (P<0.001), DS (P<0.001), more teeth with DE (P=0.026), RC (P=0.002) and ORM (P<0.001) than nonvegetarians. Daily consumption of fruits was significantly more prevalent (P<0.001), and topical fluoride application was less prevalent (P<0.001) in vegetarians compared with nonvegetarians. In particular, fluoride-containing toothpaste (P<0.001) and table salt (P=0.039) were less frequently used in vegetarians. CONCLUSION: The presented data suggest that vegetarians have an increased risk for caries and erosion. Topical fluoride application was shown to be effective in preventing caries, but not in preventing erosion.

Periodontal conditions in vegetarians: a clinical study.

BACKGROUND/OBJECTIVES: Investigations about possible correlations between vegetarian diet and periodontal conditions are rare and characterized by small case numbers. The aim of this clinical study was to investigate the influence of a vegetarian diet on periodontal parameters with an appropriate sample size. SUBJECTS/METHODS: A total of 200 patients, 100 vegetarians and 100 non-vegetarians, were included in the study. All patients were examined including a full mouth assessment of the periodontal and dental conditions. In addition, a questionnaire was handed out to ask for patients' oral hygiene habits and level of education. For statistical analysis the Mann-Whitney Test (χ(2) for analysis of the questionnaire) was applied (level of significance: P<0.05). RESULTS: Well known periodontal risk factors like age, gender and smoking habits were equally distributed within each group (71 females, 29 males, respectively and 10 smokers in each group; mean age: 41.45 years vegetarians versus 41.72 years non-vegetarians). Vegetarians had significantly lower probing pocket depths (P=0.039), bleeding on probing (P=0.001), periodontal screening index (P=0.012), a better hygiene index (P<0.001) and less mobile teeth (P=0.013). Dental examinations revealed significantly less missing teeth (P=0.018) but also more decayed (P=0.001) and eroded (P=0.026) teeth in vegetarians. Furthermore, vegetarians had a higher level of education (P<0.001), but visited dentists significantly less frequent. CONCLUSIONS: Vegetarians revealed better periodontal conditions (less inflammation signs, less periodontal damage and a better dental home care). However, it should be considered that vegetarians are not only avoiding meat in their nutrition but are also characterized by an overall healthier life style.

Probiotics affect the clinical inflammatory parameters of experimental gingivitis in humans.

OBJECTIVES: To determine the effects of a probiotic milk drink consumed over a period of 28 days, regarding the expression of clinical inflammatory parameters of the oral gingiva during various phases of plaque-induced gingivitis. METHODS: Twenty-eight adults with healthy gingiva took part in a prospective and clinical-controlled study. The test group was advised to consume a probiotic milk drink (Yacult) daily during a period of 4 weeks; the control group did not receive any probiotic food or drink. After 2 weeks of consumption of the probiotic drink, participants were advised not to brush their teeth for 14 days. Subsequently, at baseline as well as on days 1, 3, 5, 7 and 14, the following clinical parameters were assessed: plaque index (PI), gingival index (GI), gingival crevicular fluid (GCF) volume and bleeding on probing (BOP). RESULTS: At baseline, the PI was significantly higher in the test group compared with controls (0.44±0.50 vs 0.09±0.24 PI; P=0.0001). The termination of oral hygiene increased clinical inflammatory parameters in both groups. At day 14, the parameters PI, GI, GCF volume and BOP were significantly higher compared with baseline values (P=0.0001). At day 14, BOP levels (18.75±12.32 vs 36.88±12.54%) and GCF volume (18.78±16.7 vs 35.72±16.1 Periotron units) were significantly lower in the test group compared with the control group (P=0.005). CONCLUSION: The results of our study indicate that a daily consumption of a probiotic milk drink reduces the effects of plaque-induced gingival inflammation associated with a higher plaque score due to the high-carbohydrate content of the probiotic milk beverage.