Relevance of surface characteristics in the adhesiveness of polymicrobial biofilms to crown restoration materials.

We used a polymicrobial (PM) biofilm model to examine associations of bacterial adhesiveness with surface characteristics of various dental materials. Four types of dental materials (apatite pellet, zirconia, ceramic, and composite resin) with rough and mirror surfaces were used. Surface roughness, surface free energy, zeta potential, and colony-forming units (CFUs) of the biofilm formations were measured. Biofilms were cultured for 24 h under anaerobic conditions, plated onto blood agar medium, and anaerobically cultured for 4 days. After culturing, CFU per mm2 was calculated, and samples were observed under a scanning electron microscope. Means and standard deviations of the experimental data were estimated, and one-way ANOVA and Tukey multiple comparison assays were performed. Pearson correlation coefficients were obtained for the CFU and surface characteristics. Surface roughness and surface free energy appeared to affect generation of PM biofilms on oral materials, and zeta potential was involved in generation of PM biofilms on mirror-ground oral materials.

Periodontopathic bacteria in young healthy subjects of different ethnic backgrounds in Los Angeles.

BACKGROUND: The present study determined risk indicators for oral colonization by Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola in 150 children and adolescents, 4 to 16 years of age, living in Los Angeles, California. METHODS: Fifty Caucasians, 50 Hispanics, and 50 Asian-Americans completed a questionnaire on demographic characteristics. 16S rRNA-based polymerase chain reaction identification was employed to determine the presence of test bacteria in unstimulated saliva. Step-wise logistic regression analysis identified explanatory variables (risk indicators) accounting for the salivary presence of periodontopathic bacteria. RESULTS: A. actinomycetemcomitans occurred in 15%, P. gingivalis in 15%, B. forsythus in 14%, and T. denticola in 18% of all subjects. Two or more pathogens were detected in 20% of Hispanic subjects and in 12% of Asian-American subjects but not in any Caucasians (P = 0.0005, chi square test). However, no stable multivariate model including ethnicity was found for multiple pathogens. Risk for harboring any pathogens increased with the length of time lapse from last dental visit (odds ratio [OR], 4.46; 95% confidence interval [CI], 1.83 to 12.21), and decreased with higher education level of the mother (OR, 0.258; 95% CI, 0.052 to 0.875). Risk for harboring 2 or more periodontal pathogens decreased with the years the parents had resided in the United States (OR, 0.95; 95% CI, 0.901 to 0.992). Risk for harboring A. actinomycetemcomitans decreased as the number of years the parents had resided in the United States increased (OR, 0.91; 95% CI, 0.86 to 0.95), and decreased with higher income level of the father (OR, 0.201; 95% CI, 0.038 to 0.948). Girls were at higher risk for harboring P. gingivalis (OR, 2.55; 95% CI, 1.02 to 7.03), but at lower risk for carrying T. denticola (OR, 0.42; 95% CI, 0.17 to 0.98). CONCLUSIONS: This study showed that salivary occurrence of periodontopathic bacteria in young individuals was related to the length of time the parents had lived in the United States, education level of the mother, length of time since last dental visit, and gender, but apparently not to ethnicity per se.