Regional differences within the dentition for plaque, gingivitis, and anaerobic bacteria.

OBJECTIVE: This investigation assessed regional differences in dental plaque and gingivitis within the human dentition in conjunction with microbiological analyses of dental plaque. METHODS: Forty-one adults (23 males and 18 females; age range 19-44 years) were enrolled, and a calibrated dental examiner completed whole mouth examinations for dental plaque (PI) and gingivitis (GI) using the Turesky modification of the Quigley-Hein Index (TMQH) and the L6e-Silness (LS) Index, respectively. Dental plaque samples were collected from the anterior surfaces and posterior teeth to determine viable anaerobic bacteria. During this visit, subjects underwent a whole mouth dental prophylaxis and were provided a marketed fluoride dentifrice for twice-daily oral hygiene. Subjects were recalled on day 15 and day 30 for whole mouth assessments of PI and GI, followed by the collection of dental plaque from the anterior and posterior teeth for microbiological analyses during these visits. RESULTS: Low plaque and gingival scores were common on anterior surfaces, in contrast to greater frequencies of higher PI and GI scores on the posterior regions or the entire dentition. Correspondingly, mean scores for PI and GI were significantly lower among the anterior surfaces in comparison to all other regions of the mouth (posterior, Ramfjord surfaces, or the entire dentition) over each phase of the study (p < 0.0001). While prophylaxis resulted in lower clinical scores from baseline to the day-15 recall visit (p < 0.05), anterior surfaces demonstrated lower scores than posterior regions during this recall visit (p < 0.05). Although dental plaque scores increased from the day-15 to the day-30 evaluations, gingival scores maintained broad reductions, with anterior scores consistently lower than the corresponding posterior regions (p <0.05). Microbiological analyses indicated significantly lower numbers of viable bacteria from the anterior surfaces in comparison to posterior regions at both recall visits (p < 0.05). CONCLUSION: Anterior surfaces routinely demonstrated lower levels of dental plaque scores than the other regions of the dentition. Higher gingival inflammation levels were also correlated with increased plaque deposits associated with posterior teeth. Microbiological analyses confirm clinical observations with significantly higher numbers of viable bacteria in the dental plaque collected from the posterior regions. The human dentition demonstrates significant regional differences in the prevalence of dental plaque, gingivitis, and corresponding anaerobic bacteria, with posterior surfaces consistently reporting higher scores than the anterior regions. These consistent differences should be taken into account in performing plaque and gingivitis studies when assessing the efficacy of oral health products for controlling dental health.