DeVizio W

Acceleration of Purine Degradation by Periodontal Diseases

Periodontal diseases, such as gingivitis and periodontitis, are characterized by bacterial plaque accumulation around the gingival crevice and the subsequent inflammation and destruction of host tissues. To test the hypothesis that cellular metabolism is altered as a result of host-bacteria interaction, we performed an unbiased metabolomic profiling of gingival crevicular fluid (GCF) collected from healthy, gingivitis, and periodontitis sites in humans, by liquid and gas chromatography mass spectrometry. The purine degradation pathway, a major biochemical source for reactive oxygen species (ROS) production, was significantly accelerated at the disease sites. This suggests that periodontal-disease-induced oxidative stress and inflammation are mediated through this pathway. The complex host-bacterial interaction was further highlighted by depletion of anti-oxidants, degradation of host cellular components, and accumulation of bacterial products in GCF. These findings provide new mechanistic insights and a panel of comprehensive biomarkers for periodontal disease progression.

Metabolomics Reveals Elevated Macromolecular Degradation in Periodontal Disease

Periodontitis is a chronic inflammatory disease characterized by tissue destruction. In the diseased oral environment, saliva has primarily been considered to act as a protectant by lubricating the tissue, mineralizing the bones, neutralizing the pH, and combating microbes. To understand the metabolic role that saliva plays in the diseased state, we performed untargeted metabolomic profiling of saliva from healthy and periodontitic individuals. Several classes of biochemicals, including dipeptide, amino acid, carbohydrate, lipids, and nucleotide metabolites, were altered, consistent with increased macromolecular degradation of proteins, triacylglycerol, glycerolphospholipids, polysaccharides, and polynucleotides in the individuals with periodontal disease. These changes partially reflected the enhanced host-bacterial interactions in the diseased state as supported by increased levels of bacterially modified amino acids and creatine metabolite. More importantly, the increased lipase, protease, and glycosidase activities associated with periodontitis generated a more favorable energy environment for oral bacteria, potentially exacerbating the disease state.

Global Metabolomic Analysis of Human Saliva and Plasma from Healthy and Diabetic Subjects, with and without Periodontal Disease

Recent studies suggest that periodontal disease and type 2 diabetes mellitus are bi-directionally associated. Identification of a molecular signature for periodontitis using unbiased metabolic profiling could allow identification of biomarkers to assist in the diagnosis and monitoring of both diabetes and periodontal disease. This cross-sectional study identified plasma and salivary metabolic products associated with periodontitis and/or diabetes in order to discover biomarkers that may differentiate or demonstrate an interaction of these diseases. Saliva and plasma samples were analyzed from 161 diabetic and non-diabetic human subjects with a healthy periodontium, gingivitis and periodontitis. Metabolite profiling was performed using Metabolons platform technology. A total of 772 metabolites were found in plasma and 475 in saliva. Diabetics had significantly higher levels of glucose and α-hydroxybutyrate, the established markers of diabetes, for all periodontal groups of subjects. Comparison of healthy, gingivitis and periodontitis saliva samples within the non-diabetic group confirmed findings from previous studies that included increased levels of markers of cellular energetic stress, increased purine degradation and glutathione metabolism through increased levels of oxidized glutathione and cysteine-glutathione disulfide, markers of oxidative stress, including increased purine degradation metabolites (e.g. guanosine and inosine), increased amino acid levels suggesting protein degradation, and increased ω-3 (docosapentaenoate) and ω-6 fatty acid (linoleate and arachidonate) signatures. Differences in saliva between diabetic and non-diabetic cohorts showed altered signatures of carbohydrate, lipid and oxidative stress exist in the diabetic samples. Global untargeted metabolic profiling of human saliva in diabetics replicated the metabolite signature of periodontal disease progression in non-diabetic patients and revealed unique metabolic signatures associated with periodontal disease in diabetics. The metabolites identified in this study that discriminated the periodontal groups may be useful for developing diagnostics and therapeutics tailored to the diabetic population.

Evaluation of the specificity and effectiveness of selected oral hygiene actives in salivary biofilm microcosms.

The microbiological effects of biocidal products used for the enhancement of oral hygiene relate to the active compound(s) as well as other formulation components. Here, we test the specificities of selected actives in the absence of multiple excipients. Salivary ecosystems were maintained in tissue culture plate-based hydroxyapatite disc models (HDMs) and modified drip-flow biofilm reactors (MDFRs). Test compounds stannous fluoride (SF), SDS, triclosan (TCS), zinc lactate (ZL) and ZL with SF in combination (ZLSF) were delivered to the HDMs once and four times daily for 6 days to MDFRs. Plaques were characterized by differential viable counting and PCR-denaturing gradient gel electrophoresis (DGGE). TCS and SDS were the most effective compounds against HDM plaques, significantly reducing total viable counts (P<0.05), whilst SF, ZL and ZLSF were comparatively ineffective. TCS exhibited specificity for streptococci (P<0.01) and Gram-negative anaerobes (P<0.01) following a single dosing and also on repeated dosing in MDFRs. In contrast to single exposures, multiple dosing with ZLSF also significantly reduced all bacterial groups, whilst SF and ZL caused significant but transient reductions. According to PCR-DGGE analyses, significant (P<0.05) reductions in eubacterial diversity occurred following 6 day dosing with both TCS and ZLSF. Concordance of MDFR eubacterial profiles with salivary inocula ranged between 58 and 97%. TCS and ZL(SF) exhibited similar specificities to those reported for formulations. TCS was the most potent antibacterial, after single and multiple dosage regimens.

Assessment of the effects of dentifrice on periodontal disease biomarkers in gingival crevicular fluid.

BACKGROUND Periodontal disease has been studied primarily from clinical outcomes in lengthy human studies. Comprehensive biochemical profiling (metabolomics) has become a powerful tool for disease characterization and biomarker discovery. In a previous study, we performed a metabolomic analysis of gingival crevicular fluid collected from healthy, gingivitis, and periodontitis sites. Many metabolites associated with inflammation, oxidative stress, tissue degradation, and bacterial metabolism were found to be significantly induced by the diseases. METHODS A panel of 10 markers was selected from the previous metabolomic study based on their statistical significance. Thirty-nine chronic periodontitis subjects were randomly assigned to a toothpaste regimen: control dentifrice (n = 21) or triclosan-containing dentifrice ([CT] n = 18). Subjects were instructed to use their assigned dentifrice twice daily for 6 weeks. Gingival crevicular fluid samples from six healthy, six gingivitis, and three periodontitis sites were collected from each subject at baseline, 1 week, and 6 weeks. The relative levels of the markers in the samples were determined by mass spectrometry. One-sided matched-paired t tests were performed to compare data from healthy, gingivitis, and periodontitis sites. RESULTS Statistical analysis indicates that CT significantly decreased the levels of inosine, lysine, putrescine, and xanthine at the gingivitis sites as early as week 1. In contrast, control dentifrice had little effect. CONCLUSIONS This result provides biochemical confirmation for the therapeutic effects of CT on gingivitis. Biomarkers were significantly altered by CT before clinical changes were observed, suggesting that the markers have predicative value for disease state assessment.

A randomized, double-blind clinical study to assess the antimicrobial effects of a cetylpyridinium chloride mouth rinse on dental plaque bacteria.

BACKGROUND Studies with cetylpyridinium chloride (CPC) mouth rinses that range from 1 use to 6 months of use have documented the clinical efficacy of these formulations on supragingival plaque and gingivitis. OBJECTIVE The objective of the present study was to compare the effects of a commercially available mouth rinse containing 0.05% CPC versus a fluoride mouth rinse on the anaerobic bacteria found in dental plaque. Antimicrobial effects on the organisms of the supragingival plaque, a natural biofilm, were determined after 1 use and after 14 days of use of each mouth rinse. METHODS After enrollment, adult subjects from China completed a 1-week washout period and provided baseline samples of supragingival plaque for analysis of anaerobic bacteria. Subjects were randomly assigned to receive a commercially available mouth rinse formulated with 0.05% CPC or a fluoride mouth rinse. Subjects were assigned to each group according to a computer-generated randomization sequence. They were instructed to rinse with 20 mL of either the CPC or the fluoride mouth rinse for 30 seconds. Microbiologic analyses of dental plaque samples were conducted 12 hours after the first use of assigned mouth rinse. Subjects were instructed to continue twice-daily rinsing with their assigned mouth rinse for the next 14 days in addition to brushing their teeth with a commercial fluoride toothpaste. Dental plaque samples for microbiologic analyses were collected on day 15; this was done 12 hours after the final use of the assigned mouth rinses. A dentist conducted oral examinations before each sample collection to evaluate hard and soft tissue health over the course of the study. RESULTS The study included 117 adults (62 females, mean age, 28.70 years; 55 males, mean age, 30.41 years). Subjects rinsing with the CPC mouthwash (n = 58; mean age, 29.41 years) reported significant reductions in anaerobic bacteria versus those issued the fluoride rinse (n = 59; mean age, 29.61 years) 12 hours after 1 use and 12 hours after 14 days of use (P < 0.001). The mean percent reduction in anaerobic bacteria between the CPC mouth rinse and the fluoride mouth rinse was 29.98% after 1 use and 57.90% after 14 days of use. All enrolled subjects completed the study without any adverse events. CONCLUSION Use of the CPC mouth rinse was associated with significant reductions in the anaerobic bacteria of supragingival plaque compared with fluoride mouth rinse use in these adult subjects.

Effects of dentin tubule occlusion by dentifrice containing a PVM/MA bioadhesive copolymer in a silica base

OBJECTIVE To study the effectiveness of a dentifrice containing polymethyl vinyl ether-maleic acid (PVM/MA) copolymer in a silica base in occluding dentin tubules for treatment of dentin sensitivity. METHODS Thirty-two human dentin discs were divided into two groups and brushed in the morning for 30s each to study the dentifrices with and without PVM/MA copolymer. Dentin tubule occlusion and dentin permeability were evaluated with a focus variation three dimensional vertical scanning microscope (IFM) and electrochemical impedance spectroscopy (EIS). After second brushing for 30s in the afternoon the dentin discs were immersed in saliva for 16 h and then subjected to erosion using orange juice for 10 min. The effects of saliva and orange juice on tubule occlusion used in the study of dentifrices were further evaluated with IFM. RESULTS On average 97.7% of the dentin tubules were occluded after brushing in the PVM/MA group, as compared to 13.3% in the control group (p<0.0001). EIS showed that the impedance of the dentin disc increased after treatment with PVM/MA but not in the control group (p<0.05). After 16 h of storage in saliva and 10 min of erosion by orange juice, 86% of the dentin tubules remained occluded in the PVM/MA treated dentifrice. The sizes of the tubule openings were increased after orange juice erosion in the control group but not in the PVM/MA group. CONCLUSION Dentifrice containing PVM/MA copolymer in a silica base effectively occluded dentin tubules. The intra-tubular plugs were resistant to saliva and orange juice challenges.

Efficacy of a mouthwash containing 0.8% arginine, PVM/MA copolymer, pyrophosphates, and 0.05% sodium fluoride compared to a commercial mouthwash containing 2.4% potassium nitrate and 0.022% sodium fluoride and a control mouthwash containing 0.05% sodium fluoride on dentine hypersensitivity: A six-week randomized clinical study

OBJECTIVE Evaluate the efficacy of 0.8% arginine, potassium nitrate and sodium fluoride mouthwashes on dentine hypersensitivity reduction. METHODS Six week randomized, double blinded, two cell, parallel single centre clinical study in the Dominican Republic; subjects were randomized into three treatment groups: mouthwash containing 0.8% arginine, PVM/MA copolymer, pyrophosphates, and 0.05% sodium fluoride in an alcohol-free base (arginine); mouthwash containing 2.4% potassium nitrate and 0.022% sodium fluoride (potassium nitrate); a control mouthwash containing 0.05% sodium fluoride (negative control). Tactile and air-blast dentine hypersensitivity assessments were conducted at baseline, thirty minutes post rinsing and two, four, and six weeks of twice-daily product use. For treatment group comparisons, ANCOVA and post hoc Tukeys pair-wise comparisons (α=0.05) were done. RESULTS Seventy-five subjects were enrolled; 69 subjects completed the study. There were no differences after thirty minutes of a single use, among the three groups with respect to mean tactile and air blast hypersensitivity scores compared to potassium nitrate and negative control mouthwashes (p<0.05). The arginine group presented a statistically significant improvement in the mean tactile scores compared to potassium nitrate and negative control groups after two, four, and six weeks (p<0.001) of product use; the arginine group showed a statistically significant enhancement in air blast hypersensitivity mean scores compared to potassium nitrate and negative control groups after two (p=0.001), four (p<0.001), and six weeks (p<0.001) of product use. CONCLUSION A mouthwash containing arginine provides a significant and superior reduction in dentine hypersensitivity compared to potassium nitrate and a negative control mouthwash after two weeks.

Antimicrobial effects of a new therapeutic liquid dentifrice formulation on oral bacteria including odorigenic species.

The control of oral malodor is well-recognized in efforts to improve oral health. Antimicrobial formulations can mitigate oral malodor, however, procedures to assess effects on oral bacteria including those implicated in halitosis are unavailable. This investigation examined the antimicrobial effects of a new liquid triclosan/copolymer dentifrice (test) formulation that demonstrated significant inhibition of oral malodor in previous organoleptic clinical studies. Procedures compared antimicrobial effects of the test and control formulations on a range of oral micro-organisms including members implicated in halitosis, substantive antimicrobial effects of formulations with hydroxyapatite as a surrogate for human teeth and ex vivo effects on oral bacteria from human volunteers. With Actinomyces viscosus, as a model system, the test formulation demonstrated a dose-dependent effect. At these concentrations the test formulation provided significant antimicrobial effects on 13 strains of oral bacteria including those implicated in bad breath at selected posttreatment time points. Treatment of hydroxyapatite by the test dentifrice resulted in a significant and substantive antimicrobial effect vs. controls. Oral bacteria from subjects treated ex vivo with the test dentifrice resulted in significant reductions in cultivable oral bacteria and odorigenic bacteria producing hydrogen sulfide. In summary, microbiological methods adapted to study odorigenic bacteria demonstrate the significant antimicrobial effects of the test (triclosan/copolymer) dentifrice with laboratory and clinical strains of oral bacteria implicated in bad breath.