Faculty Bibliography

BACKGROUND: The purpose of this study was to assess treatment responses to dental flossing in twins. METHODS: The study was a two-treatment, examiner-blind, randomized parallel group, controlled study. Fifty-one twin pairs between 12 and 21 years of age were randomized to a 2-week supervised and unsupervised treatment regimen consisting of 1) tongue brushing and toothbrushing (TB) and 2) TB + flossing (TB + Fl). Clinical endpoints were gingival bleeding (papillary bleeding score [PBS]) and oral malodor (levels of volatile sulfur compounds [VSC]). Analysis of variance and covariance methodologies were employed to analyze the data. RESULTS: Baseline average PBS values were 1.352 and 1.345 for the TB + Fl and TB groups, respectively (P=0.937). After 2 weeks of treatment, the TB + Fl group had a statistically significant decrease in PBS values of 0.558 (41.5% versus baseline), whereas the TB group showed no improvement from baseline. The change from baseline for the TB + Fl group was superior to that for the TB group (P<0.001). Similar findings were observed for the number of baseline papillary bleeding sites. Baseline average intraoral halimeter values were 45.91 and 41.75 for the TB+Fl and TB groups, respectively (P=0.504). Both treatment regimens demonstrated highly statistically significant reductions in intraoral halimeter values versus baseline (all P<0.001) and the difference between treatment groups was not statistically significant (P=0.339). Similar findings were found for expired air. CONCLUSIONS: In a well-matched twin cohort, tongue and toothbrushing plus flossing significantly decreased gingival bleeding after 2 weeks

This paper illustrates the use of biometrics through the application of an iris-based biometrics system for identifying twins and their parents in a longitudinal research study. It explores the use of biometrics (science of measuring physical or anatomical characteristics of individuals) as a technology for correct identification of individuals during longitudinal studies to help ensure data fidelity. Examples of these circumstances include longitudinal epidemiological and genetic studies, clinical trials, and multicenter collaborative studies where accurate identification of subjects over time can be difficult when the subject may be young or an unreliable source of identification information. The use of technology can automate the process of subject identification thereby reducing the need to depend on subject recall during repeated visits thus helping to ensure data quality. This case report provides insights that may serve as useful hints for those responsible for planning system implementation that involves participants' authentication that would require a more secure form of identification

OBJECTIVE: The purpose of this study was to investigate compliance of long-term xylitol and sorbitol chewing gum regimens in adult women participating in a double-blind randomized controlled clinical trial. DESIGN: The participants included 122 mothers (age range: 16-35 years) residing in the city of Bauru, Sao Paulo, Brazil. Compliance with the xylitol and sorbitol chewing gum regimens was assessed by weighing, with a precision balance, all used gums returned in zip-lock bags during the study period of 33 months. The total number of returned bags in both chewing gum groups was computed and the differences between groups were determined by one-way ANOVA. Compliance was further categorized into excellent, good, fair or poor based on the distribution of the combined data for both groups by quartiles. These distributions for the xylitol and sorbitol groups were subjected to chi-square analysis. RESULTS: Compliance was always superior for the xylitol group in all categories. These distributions were, however, not significantly different in statistical terms. Average compliance in the xylitol chewing gum group was significantly higher when compared to the sorbitol chewing gum group (p=0.0481). CONCLUSIONS: The results suggest that compliance, and possibly acceptance in this population, was superior for xylitol chewing gum than for sorbitol chewing gum.

OBJECTIVE: The purpose of this study was two-fold: 1) to determine the effects of mechanical and chemical modalities treatments on periodontal clinical and microbiological parameters of mothers; and 2) to determine the subsequent colonization of periodontal pathogens in tongue samples from their infants. DESIGN: A total of 168 mothers met inclusion criteria to participate in a randomized double-masked placebo-controlled clinical trial. Of those, 121 mothers (and their infants) of 158 seen at baseline provided complete data during study protocols from when their infants were 3 months old until the infants were about 2 years old. Treatments consisted of a combination of xylitol chewing gum, fluoride and chlorhexidine varnishes. The control/placebo group received sorbitol chewing gum and placebo varnishes. The effect of these treatments on periodontal clinical and microbiological parameters of mothers and on microbiological parameters of their infants was assessed by generalized estimating equation models. RESULTS: Microbiological outcomes using the BANA Test were lower for the majority of the visits in the test group when compared to the control/placebo group. These differences, however, were not statistically significant. Similarly, mean PBS results were lower for all follow-up visits for test-group mothers when compared to the control/placebo group's mothers, but of no statistical significance. Colonization of the tongue in infants by periodontal pathogens as measured by the BANA Test showed no distinct patterns concerning the stability of colonization of periodontal pathogens throughout the study period, albeit slightly superior for the test group. CONCLUSIONS: We have demonstrated that a combined chemical modalities treatment consisting of xylitol chewing gum, fluoride varnish and chlorhexidine varnish was moderately superior to control/placebo treatments on periodontal clinical and microbiological parameters of mothers throughout the study period, but of no statistical significance. Similar results were found for the infants in the test group when compared to infants of the control/placebo groups.

BACKGROUND: The objective of this study was to examine the relationship between airway obstruction and periodontal disease. METHODS: Participants were a subset of 860 community- dwelling, well functioning elderly (aged 70 to 79, blacks and whites, males and females) selected from 2,732 participants enrolled in the Health, Aging, and Body Composition Study (Health ABC). The periodontal evaluations occurred over years 2 and 3 of the study and included four indices of periodontal health: plaque index (PI), gingival index (GI), probing depth (PD), and loss of attachment (LOA). The pulmonary evaluation took place in year 1: conducted according to American Thoracic Society criteria, based on the forced expiratory volume/forced vital capacity (FEV1/FVC) ratio and then using the percent of predicted FEV1 to categorize severity. RESULTS: GI (P = 0.023) and LOA (P = 0.009) were significantly better in participants with normal pulmonary function compared to those with airway obstruction after adjusting for age, race, gender, and field center. When stratified by smoking status and after adjusting for age, race, gender, center, and pack-years, there was a significant association between periodontal health and airway obstruction in former smokers. Within this group, those with normal pulmonary function had significantly better GI (P = 0.036) and LOA (P = 0.0003) scores than those with airway obstruction. All periodontal indices were elevated in smokers regardless of pulmonary status; however, the current smoker group was too small to detect a periodontitis effect. CONCLUSION: While the present cross-sectional study cannot provide direct inference of cause and effect, it does reveal a significant association between periodontal disease and airway obstruction, particularly in former smokers

The aim of this study was to use molecular identification methods, such as 16S RNA gene sequence and reverse-capture checkerboard hybridization, for identification of the bacteria associated with dental caries and with dental health in a subset of 204 twins aged 1.5 to 7 years old. A total of 448 plaque samples (118 collected from caries-free subjects and 330 from caries-active subjects) were used for analysis. We compared the bacteria found in biofilms of children exhibiting severe dental caries, with different degrees of lesion severity, with those found in biofilms of caries-free children. A panel of 82 bacterial species was selected, and a PCR-based reverse-capture checkerboard method was used for detection. A simple univariate test was used to determine the overabundance and underabundance of bacterial species in the diseased and in the healthy groups. Features identified with this univariate test were used to construct a probabilistic disease prediction model. Furthermore, a method for the analysis of global patterns of gene expression was performed to permit simultaneous analysis of the abundance of significant species by allowing cross-bacterial comparisons of abundance profiles between caries-active and caries-free subjects. Our results suggested that global patterns of microbial abundance in this population are very distinctive. The top bacterial species found to be overabundant in the caries-active group were Actinomyces sp. strain B19SC, Streptococcus mutans, and Lactobacillus spp., which exhibited an inverse relationship to beneficial bacterial species, such as Streptococcus parasanguinis, Abiotrophia defectiva, Streptococcus mitis, Streptococcus oralis, and Streptococcus sanguinis

The role of genetic and environmental factors on dental caries progression in young children was determined. A detailed caries assessment was performed in 2 examinations on 314 pairs of twins initially 1.5 to 8 years old. Surface-based caries prevalence rates (SBCPR) and lesion severity (LSI) were computed. Heritability estimates were calculated by SOLAR software. Analyses were performed on all ages combined and by age group (1.5-< 4; 4-6; > 6). Overall heritability estimates (H) of net increments SBCPRs were H = 30.0 (p < 0.0001), and were greatest for the youngest (H = 30.0) and oldest groups (H = 46.3). Overall LSI heritability estimates [H = 36.1 (p < 0.0001)] were also greatest for the youngest (H = 51.2) and oldest groups (H = 50.6). Similar findings were found for net increments of occlusal surfaces and deep dentinal lesions SBCPRs (H = 46.4-56.2). These findings are consistent with a significant genetic contribution to dental caries progression and severity in both emerging primary and permanent dentitions

OBJECTIVES: To study the levels of systemic markers for inflammation with parameters of periodontal diseases in older people. DESIGN: A cross-sectional study was conducted in a cohort that is being followed prospectively on the effects of aging and body composition on morbidity. SETTING: University of Pittsburgh, Pittsburgh, and University of Tennessee, Memphis. PARTICIPANTS: One thousand one hundred thirty-one participants (mean age+/-standard deviation 72.7+/-2.8); 66% white and 50% male. MEASUREMENTS: Periodontal examination, including probing depth and attachment loss, was performed. Periodontal disease extent was divided into 0% of sites with probing depth of 6 mm or more, 1% to 10% of sites with probing depth of 6 mm or more and more than 10% of sites with probing depth of 6 mm or more. Subgingival plaque samples were collected from four molar teeth, and the levels of periodontal pathogens were determined using the benzoyl-DL-arginine-naphthylamide (BANA) test. Plasma interleukin-6 (IL-6), C-reactive protein (CRP), plasminogen activator inhibitor type-1 (PAI-1), and tumor necrosis factor alpha (TNF-alpha) levels were measured in all participants. Assessments of risk factors associated with elevated levels of markers of systemic inflammation were also determined. Multiple regression analysis was employed to analyze the data. RESULTS: IL-6 levels were significantly higher in participants with more-extensive periodontal disease than in other participants. Periodontal disease extent was significantly associated with higher TNF-alpha plasma levels, controlling for established risk factors for elevated TNF-alpha levels. Participants with BANA-positive species had significantly higher CRP plasma levels when controlling for risk factors for elevated CRP levels. CONCLUSION: Periodontal disease and infection may be modifiable risk indicators for elevated levels of systemic inflammatory markers in older people

OBJECTIVE: To determine the relative contribution of genetic and environmental stimuli on dental caries traits and microbial acid production in a twin model. METHODS: Dental caries examinations and microbial acid production assays were performed on 388 pairs of twins 1.5-8 years old from the city of Montes Claros, Brazil. Genotyping 8 polymorphic DNA markers determined zygosity. Caries exams followed NIDCR criteria modified to distinguish white spot lesions from cavitated lesions. Surface-based caries prevalence rates (SBCPR) were computed and lesion severity was determined by a weighted index (LSI). Biofilm samples were collected from the tongue using a lactic acid indicator swab. Assay scores were categorized based on acid formation as 1 = low, 2 = medium, and 3 = high. Heritability analyses were performed using the SOLAR software package. RESULTS: Heritability estimates for SBCPRs, LSI and for microbial acid production were H = 76.3 (p < 0.001), H = 70.6 (p < 0.001), H = 16.2 (p = 0.0078), respectively. Treating microbial acid production as a covariate in the SBCPR and LSI models did not significantly alter the heritability estimates, i.e. H = 76.5 (p < 0.001) and H = 70.8 (p < 0.001), respectively. CONCLUSIONS: These results suggest that variation in dental caries surface traits has a significant genetic contribution and that microbial acid production is modulated by the environment

OBJECTIVE: The purpose of this study was to determine whether genetic factors influence variation in salivary levels of the mutans streptococci (MS) in preschool twins. DESIGN: The study population consisted of 48 pairs of monozygotic (MZ) twins and 54 pairs of dizygotic (DZ) twins. Genotyping eight highly polymorphic DNA markers determined zygosity. Demographic data and antibiotic exposure as reported by mothers were obtained by a face-to-face interview. Salivary levels of MS were determined by the Stripmutanstrade mark test. Test results are reported on a scale of 0-3. Regression analysis, two sample t-tests and structural equation modeling were applied to analyse the data. RESULTS: Only 6% of the participants ever visited a dentist (F component of the DMFS was 0 for this population). Average salivary scores for the mutans streptococci were significantly different between MZ (1.1+/-0.1) and DZ (0.8+/-0.1) twins (p=0.021). High salivary levels of MS (scores 2 and 3) were observed in 42% of MZ twins and in 26% of DZ twins. Regression analysis on the MS salivary levels revealed no significant effects of age, gender and antibiotic intake for MZ or DZ twins. The heritability of mutans streptococci colonisation in 48 pairs MZ and in 26 pairs of DZ twins was estimated to be 52%. The non-shared environment contribution was estimated to be 48%. CONCLUSIONS: These results suggest that variation in the salivary levels of the mutans streptococci is significantly contributed by genetic factors