Increased Hyaluronan and TSG-6 in Association with Neuropathologic Changes of Alzheimer's Disease

Little is known about the extracellular matrix (ECM) during progression of AD pathology. Brain ECM is abundant in hyaluronan (HA), a non-sulfated glycosaminoglycan synthesized by HA synthases (HAS) 1-3 in a high molecular weight (MW) form that is degraded into lower MW fragments. We hypothesized that pathologic severity of AD is associated with increases in HA and HA-associated ECM molecules. To test this hypothesis, we assessed HA accumulation and size; HA synthases (HAS) 1-3; and the HA-stabilizing hyaladherin, TSG-6 in parietal cortex samples from autopsied research subjects with not AD (CERAD = 0, Braak = 0- II, n = 12-21), intermediate AD (CERAD = 2, Braak = III-IV, n = 13-18), and high AD (CERAD = 3, Braak = V-VI, n = 32-40) neuropathologic change. By histochemistry, HA was associated with deposits of amyloid and tau, and was also found diffusely in brain parenchyma, with overall HA quantity (measured by ELSA) significantly greater in brains with high AD neuropathology. Mean HA MW was similar among the samples. HAS2 and TSG-6 mRNA expression, and TSG-6 protein levels were significantly increased in high AD and both molecules were present in vasculature, NeuN-positive neurons, and Iba1-positive microglia. These results did not change when accounting for gender, advanced age (≥ 90 years versus <90 years), or the clinical diagnosis of dementia. Collectively, our results indicate a positive correlation between HA accumulation and AD neuropathology, and suggest a possible role for HA synthesis and metabolism in AD progression.

Pre-existing Cardiovascular Disease and Periodontitis: A Follow-up Study

Periodontal infections in individuals with pre-existing heart disease are believed to increase the risk for future coronary heart disease (CHD) events. The goal of this study was to search for an association between periodontitis and CHD events among individuals with pre-existing heart disease, reported in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Dentate adults (n = 636) with a history of pre-existing cardiovascular disease were followed for CHD events. The presence of periodontitis and gingivitis did not increase CHD risk among these at-risk individuals (hazard ratio [HR], 0.97, and 95% confidence interval [CI], 0.72-1.31; and HR, 1.09, and 95% CI, 0.79-1.50, respectively). When limited to individuals with a self-reported prior heart attack, periodontitis was associated with a 34% decreased CHD risk (HR, 0.66; 95% CI, 0.42–1.05). It is concluded that periodontitis or gingivitis does not elevate CHD risk among individuals with a prior heart attack or self-reported pre-existing cardiovascular disease.

Evaluation of Bond Strength and Microleakage of a Novel Metal-titanate Antibacterial Agent

OBJECTIVES

To evaluate the effect on both bond strength and microleakage of incorporation of a novel antibacterial nanoparticulate metal-titanate complex (nMT) into a dental adhesive system.

MATERIALS AND METHODS

Eighty extracted human molars were prepared to determine whether incorporation of nMT into bonding agents can affect shear bond strength (SBS) and adhesive strength fatigue. SBS was measured with a universal testing machine, and the peak force at failure was recorded. An electromechanical fatigue machine was used for cyclic loading treatment of specimens. Differences in the SBS values among groups were identified using analysis of variance and Tukey post hoc analyses (α=0.05). Twenty standard Class V cavities were restored to examine microleakage when the primer/bonding resin was modified with 10 wt% nMT. Microleakage at the enamel and dentin margins was calculated as a percentage of the full length of the cavity. Results of the microleakage experiment were analyzed with paired and independent sample t-tests (α=0.05).

RESULTS

The mean (± standard deviation) shear bond strength values of before fatigue and after fatigue ranged from 21.9 (2.5) MPa to 23.9 (3.8) MPa and from 17.1 (2.5) MPa to 17.7 (2.5) MPa respectively. No statistically significant differences in failure force were observed among groups (p=0.70). Microleakage under all conditions was significantly greater in the dentin margins than in the enamel margins (p<0.05). There was no evidence that microleakage differed between the experimental groups with modified primer and bonding resin.

CONCLUSIONS

Incorporating nMT into a dental adhesive system will not compromise the resin composite's tooth bonding and sealing ability.

Randomized equivalence trial of intensive and semiannual applications of fluoride varnish in the primary dentition

For children in the primary dentition with high caries prevalence the standard semiannual application of fluoride varnish may not be successful in preventing tooth decay. Oftentimes this population is mobile and does not receive consistent preventive care. This trial tested whether an intensive fluoride 5% sodium varnish regimen (three applications/2 weeks) applied annually has an equivalent effect on caries progression in the primary dentition compared to single applications applied semiannually. This study was a randomized clinical trial with two treatment groups. All participants (n = 600; mean age +/- SD = 55.3 +/- 4.6 months) received three varnish applications (active varnish or placebo) at semiannual visits over 3 years. Once per year the intensive-treatment group received one set of three active treatments and three placebo treatments 6 months later, each time within 2 weeks. The standard group received one active and two placebo treatments every 6 months. Children were assessed clinically at baseline and 12, 24 and 36 months after the initiation of the study. The mean (SD) numbers of newly decayed primary tooth surfaces observed over 3 years were 9.8 (8.6) and 7.4 (7.7) in the intensive and standard groups, respectively. The adjusted rate ratio was 1.13 (95% CI = 0.94-1.37, p = 0.20). In conclusion, the trial failed to demonstrate clear evidence of a difference in efficacy. However, differences of up to 36% greater rates of caries in the intensive group could not be ruled out, thus equivalence of the treatments cannot be concluded.

Racial and ethnic differences in a regular source of dental care and the oral health, behaviors, beliefs and services of low-income mothers

OBJECTIVE

In a racial/ethnically-diverse sample of low-income mothers of children aged 3-6, we determine: (1) whether a regular source of dental care (RSDC), self-rated oral health, beliefs and behaviors differ by racial/ethnic group; (2) estimate whether a RSDC is associated with oral health, beliefs and behaviors, and whether these associations differ by racial/ethnic group; and (3) examine these relationships for mothers' dental utilization.

BASIC RESEARCH DESIGN

Cross-sectional survey. Participants From a population of 108,151 Medicaid children aged 3-6 in Washington state, U.S., 10,909 eligible children were sampled stratified by racial/ethnic group. Eligible mothers completed a mixed-mode survey in the following groups: Black (n=818), Hispanic (n=1310), or White (n=1382).

MAIN OUTCOME MEASURES

Measures were mothers' RSDC, personal characteristics, self-rated dental health, appearance of teeth, dental problems, brushing duration, flossing frequency, use of toothpicks or whiteners, belief that cleaning prevents cavities or loose teeth, and self-reported services at last dental visit.

RESULTS

About 38-40% of mothers had a RSDC. For Black, Hispanic and White mothers, having a RSDC was associated consistently with better oral health, greater likelihood of a dental cleaning and less likelihood of tooth extraction. RSDC was not associated generally with oral health beliefs and behaviors. Oral health behaviors differ by racial/ethnic group.

CONCLUSIONS

Relationships between RSDC and self-reported oral health, health behaviors, beliefs and dental services are similar for Black, Hispanic and White low-income mothers of young children. Oral health behaviors differ across racial/ethnic groups, which may have implications for mother and child oral health.

Pre-existing cardiovascular disease and periodontitis: a follow-up study

Periodontal infections in individuals with pre-existing heart disease are believed to increase the risk for future coronary heart disease (CHD) events. The goal of this study was to search for an association between periodontitis and CHD events among individuals with pre-existing heart disease, reported in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Dentate adults (n = 636) with a history of pre-existing cardiovascular disease were followed for CHD events. The presence of periodontitis and gingivitis did not increase CHD risk among these at-risk individuals (hazard ratio [HR], 0.97, and 95% confidence interval [CI], 0.72-1.31; and HR, 1.09, and 95% CI, 0.79-1.50, respectively). When limited to individuals with a self-reported prior heart attack, periodontitis was associated with a 34% decreased CHD risk (HR, 0.66; 95% CI, 0.42-1.05). It is concluded that periodontitis or gingivitis does not elevate CHD risk among individuals with a prior heart attack or self-reported pre-existing cardiovascular disease.

Examining the link between coronary heart disease and the elimination of chronic dental infections

BACKGROUND

While it has been suggested that periodontal disease may be associated with coronary heart disease, or CHD, there are no data to suggest that the elimination of chronic dental infections actually lowers the risk of developing chronic CHD. The goal of this study was to determine whether people with a definitive elimination of all potential dental infections--edentulous people, who are at the optimum endpoint of dental infection elimination from a CHD perspective--lower their CHD risk over time when compared with people who have a specific dental infection, periodontitis.

METHODS

The authors examined data from a prospective cohort of 4,027 people who participated in the First National Health and Nutrition Examination Survey, or NHANES I, Epidemiologic Follow-up Study. The primary outcome measure was the first CHD event.

RESULTS

During a mean follow-up of 17 years, there were 1,238 CHD events (538 fatal). The confirmed elimination of chronic dental infections did not lead to a decreased risk of experiencing a CHD event (relative risk, 1.02; 95 percent confidence interval, 0.86-1.21). The CHD risk among people with and without chronic dental infections remained constant over time with respect to each other (test for increasing or decreasing trend over time: not significant, chi2(1) = 0.48; P = .93).

CONCLUSIONS

People who had a complete, definitive and long-term elimination of all potential dental infections through extraction of all teeth did not have lower CHD risk when compared with people with diagnosed periodontitis.

CLINICAL IMPLICATIONS

Until evidence is found to the contrary, the authors suggest that prevention of CHD should not be used as the basis for recommending treatment to eliminate chronic dental infections.

Periodontal disease and coronary heart disease risk

CONTEXT

Research has suggested a relationship between periodontal disease and coronary heart disease (CHD), but data on the association between these 2 common conditions are inconclusive due to the possibility of confounding.

OBJECTIVE

To evaluate the risk of CHD in persons with periodontitis, gingivitis, or no periodontal disease.

DESIGN

Prospective cohort study.

SETTING

The First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study, conducted in 1982-1984, 1986, 1987, and 1992.

PARTICIPANTS

A total of 8032 dentate adults aged 25 to 74 years with no reported history of cardiovascular disease, including 1859 individuals with periodontitis, 2421 with gingivitis, and 3752 with healthy periodontal tissues.

MAIN OUTCOME MEASURE

First occurrence of death from CHD or hospitalization due to CHD, or revascularization procedures, obtained from death certificates and medical records, by baseline periodontal status.

RESULTS

During follow-up, 1265 individuals had at least 1 CHD event, including CHD fatality (n = 468) or at least 1 hospitalization with a diagnosis of CHD (n = 1022), including coronary revascularization procedures (n = 155). After adjustment for known cardiovascular risk factors, gingivitis was not associated with CHD (hazard ratio, 1.05; 95% confidence interval, 0.88-1.26), while periodontitis was associated with a nonsignificant increased risk for CHD event (hazard ratio, 1. 14; 95% confidence interval, 0.96-1.36).

CONCLUSION

This study did not find convincing evidence of a causal association between periodontal disease and CHD risk. JAMA. 2000;284:1406-1410.