Frequency of Tongue Cleaning Impacts the Human Tongue Microbiome Composition and Enterosalivary Circulation of Nitrate.

The oral microbiome has the potential to provide an important symbiotic function in human blood pressure physiology by contributing to the generation of nitric oxide (NO), an essential cardiovascular signaling molecule. NO is produced by the human body via conversion of arginine to NO by endogenous nitric oxide synthase (eNOS) but eNOS activity varies by subject. Oral microbial communities are proposed to supplement host NO production by reducing dietary nitrate to nitrite via bacterial nitrate reductases. Unreduced dietary nitrate is delivered to the oral cavity in saliva, a physiological process termed the enterosalivary circulation of nitrate. Previous studies demonstrated that disruption of enterosalivary circulation via use of oral antiseptics resulted in increases in systolic blood pressure. These previous studies did not include detailed information on the oral health of enrolled subjects. Using 16S rRNA gene sequencing and analysis, we determined whether introduction of chlorhexidine antiseptic mouthwash for 1 week was associated with changes in tongue bacterial communities and resting systolic blood pressure in healthy normotensive individuals with documented oral hygiene behaviors and free of oral disease. Tongue cleaning frequency was a predictor of chlorhexidine-induced changes in systolic blood pressure and tongue microbiome composition. Twice-daily chlorhexidine usage was associated with a significant increase in systolic blood pressure after 1 week of use and recovery from use resulted in an enrichment in nitrate-reducing bacteria on the tongue. Individuals with relatively high levels of bacterial nitrite reductases had lower resting systolic blood pressure. These results further support the concept of a symbiotic oral microbiome contributing to human health via the enterosalivary nitrate-nitrite-NO pathway. These data suggest that management of the tongue microbiome by regular cleaning together with adequate dietary intake of nitrate provide an opportunity for the improvement of resting systolic blood pressure.

Alcohol intake and periodontitis in adults aged ≥30 years: NHANES 2009-2012.

BACKGROUND: Whether an association between alcohol consumption and periodontitis exists is still unclear. This study aimed to assess the association between alcohol consumption and periodontitis. METHODS: 7062 adults 30 years or older who participated in 2009-2010 and 2011-2012 cycles of the National Health and Nutrition Examination Survey (NHANES) were included. Alcohol consumption measurement included self-reported average number of alcoholic drinks per week over the previous 12 months and was categorized into four groups (0, < 1, 1- < 8, and ≥8 drinks per week). Participants were categorized using surveillance case definitions for periodontitis that included both clinical attachment level (CAL) and periodontal probing depth (PD) measurements. The association between alcohol consumption and chronic periodontitis was evaluated by multivariable regression analyses adjusting for age, gender, race/ethnicity, education level, income-to-poverty ratio, smoking, self-rated overall oral health, and HbA1c . RESULTS: The odds ratio (95% confidence interval) of having severe periodontitis was 1.9 (1.2-3) among participants who reported alcohol consumption of ≥8 drinks compared to participants consuming some alcohol but < 1 drink per week on average. Participants who consumed 1- < 8, and ≥8 drinks per week, on average, also had higher mean PD, percentage of sites with PD ≥4 mm, mean CAL, and percentage of sites with CAL ≥3 mm compared to participants reporting consumption of < 1 drink per week. Meanwhile, the odds of having periodontitis, mean PD, extent PD ≥4 mm, mean CAL, and extent CAL ≥3 mm were not significantly different for nondrinkers than for participants who consumed some alcohol but < 1 drink per week on average. CONCLUSIONS: Alcohol consumption was associated with an increase in the likelihood of having periodontitis, particularly severe periodontitis. Consumption of some alcohol, < 1 drink per week on average, was associated with similar odds of having periodontitis compared to consumption of no alcohol.

Survival of Dental Implants Placed in Grafted and Nongrafted Bone: A Retrospective Study in a University Setting.

PURPOSE: To compare dental implant survival rates when placed in native bone and grafted sites. Additionally, risk factors associated with dental implant loss were identified. This study was based on the hypothesis that bone grafting has no effect on implant survival rates. MATERIALS AND METHODS: A retrospective chart review was conducted for patients receiving dental implants at the University of Texas, School of Dentistry from 1985 to 2012. Exclusion criteria included patients with genetic diseases, radiation and chemotherapy, or an age less than 18 years. To avoid misclassification bias, implants were excluded if bone grafts were only done at the same time of placement. Data on age, sex, tobacco use, diabetes, osteoporosis, anatomical location of the implant, implant length and width, bone graft, and professional maintenance were collected for analysis. RESULTS: A total of 1,222 patients with 2,729 implants were included. The cumulative survival rates at 5 and 10 years were 92% and 87% for implants placed in native bone and 90% and 79% for implants placed in grafted bone, respectively. The results from multivariate analysis (Cox regression) indicated no significant difference in survival between the two groups; having maintenance therapy after implant placement reduced the failure rate by 80% (P < .001), and using tobacco increased the failure rate by 2.6-fold (P = .001). CONCLUSION: There was no difference in the dental implant survival rate when implants were placed in native bone or bone-grafted sites. Smoking and lack of professional maintenance were significantly related to increased implant loss.

Partial-mouth periodontal examination protocol for estimating periodontitis extent and severity in a US population.

We have previously demonstrated that half-mouth four-site periodontal examination protocol performed well in estimating periodontitis prevalence. This study aimed to assess biases associated with this same protocol in estimating periodontitis extent and severity in a United States population. Periodontitis extent as determined by percentage of sites with clinical attachment loss (CAL) ≥3, and ≥5 mm and severity as determined by mean CAL were calculated for full-mouth examination and half-mouth four-site protocol based on 3734 adults sampled from the National Health and Nutrition Examination Survey 2009-2010. Probing depth was excluded because of low data reliability. The comparison between full-mouth and half-mouth assessments was based on bias, relative bias, Wilcoxon signed-rank test, and intra-class correlation coefficient (ICC). For full-mouth examination, periodontitis extent was 21.2% for CAL ≥3 mm and 6.9% for CAL ≥5 mm; periodontitis severity (mean CAL) was 1.73 mm. Half-mouth four-site protocol provided bias -1.2% and relative bias -5.7% for extent (CAL ≥3 mm). Corresponding numbers were -0.3% and 4.3% for extent (CAL ≥5 mm), -0.05 mm and -2.9% for severity. Although the difference between full-mouth and half-mouth assessments was statistically significant, ICCs between them were ≥0.96 for extent (CAL ≥3, 5 mm), and severity (mean CAL). Half-mouth four-site protocol performed well in estimating periodontitis extent and severity based on CAL. Therefore, this protocol should be considered for periodontitis surveillance.

The effect of periodontal therapy on glycaemic control in a Hispanic population with type 2 diabetes: a randomized controlled trial.

OBJECTIVE: In the Mexican-American population, the prevalence of Type 2 diabetes mellitus (T2DM) is as high as 50% of the population. This randomized controlled clinical trial was designed to elucidate how treatment of periodontal disease affects HbA1c values in this population. MATERIALS AND METHODS: One hundred and fifty-four T2DM patients with periodontal disease were enrolled in the study. The test group was treated with scaling and root planing (SRP); the control group received oral hygiene instructions. At baseline and 4-6 weeks after therapy, a complete periodontal examination was performed. Blood was collected at baseline and 4 months later for HbA1c levels. RESULTS: One hundred and twenty-six individuals completed the study. Baseline mean ± SD HbA1c for the test and control groups were 9.0 ± 2.3% and 8.4 ± 2.0% respectively. Non-significant difference in HbA1c reductions (0.6 ± 2.1% and 0.3 ± 1.7%) was found between test and control groups at 4 months. Comparisons of the periodontal clinical parameters between the test and control groups found significant differences with improved results in the test subjects. CONCLUSIONS: No statistically significant differences were found in the changes of HbA1c levels between test and control groups. Non-surgical periodontal therapy improved the magnitude of change in periodontal parameters as compared to the control subjects. ClinicalTrials.gov Identifier: NCT01128374.

Domain of dentine sialoprotein mediates proliferation and differentiation of human periodontal ligament stem cells.

Classic embryological studies have documented the inductive role of root dentin on adjacent periodontal ligament differentiation.  The biochemical composition of root dentin includes collagens and cleavage products of dentin sialophosphoprotein (DSPP), such as dentin sialoprotein (DSP).  The high abundance of DSP in root dentin prompted us to ask the question whether DSP or peptides derived thereof would serve as potent biological matrix components to induce periodontal progenitors to further differentiate into periodontal ligament cells. Here, we test the hypothesis that domain of DSP influences cell fate. In situ hybridization and immunohistochemical analyses showed that the COOH-terminal DSP domain is expressed in mouse periodontium at various stages of root development. The recombinant COOH-terminal DSP fragment (rC-DSP) enhanced attachment and migration of human periodontal ligament stem cells (PDLSC), human primary PDL cells without cell toxicity. rC-DSP induced PDLSC cell proliferation as well as differentiation and mineralization of PDLSC and PDL cells by formation of mineralized tissue and ALPase activity. Effect of rC-DSP on cell proliferation and differentiation was to promote gene expression of tooth/bone-relate markers, transcription factors and growth factors. The results for the first time showed that rC-DSP may be one of the components of cell niche for stimulating stem/progenitor cell proliferation and differentiation and a natural scaffold for periodontal regeneration application.