Systemic neutrophil response resulting from dental plaque accumulation

Background: There is considerable current interest in putative relationship s between oral and systemic diseases. Since the host response to oral bacte ria may be the critical link in this association, our hypothesis was that d ental plaque accumulation in healthy subjects would elicit a systemic infla mmatory response. Methods: Twenty-three healthy subjects, aged 18 to 25, participated in a 4- phase study. An initial hygiene phase was followed by a 21-day experimental phase (the so-called experimental gingivitis model) in which subjects refr ained from all oral hygiene practices, thus permitting the accumulation of bacterial plaque. At days 0, 7, and 21 total and differential peripheral wh ite blood cell (wbc) counts, together with full mouth plaque and gingivitis scores, were recorded. Following a 28-day recovery phase, in which normal oral hygiene practices were resumed, subjects entered the final 21-day cont rol phase which mirrored the experimental phase but with subjects maintaini ng normal oral hygiene practices. Results: The experimental model performed as anticipated with a correlation between plaque and gingivitis scores of 0.95, also reflecting subject comp liance. Total wbc and neutrophil counts increased during the experimental p hase. Furthermore, comparison of neutrophil counts between the experimental and control phases demonstrated a significantly higher cell count for the experimental phase on both days 7 and 21 (P = 0.0301 and 0.009, respectivel y). For total wbc, this was significant on day 21 (P = 0.0262). Conclusion: The results of this study support the hypothesis that the accum ulation of dental plaque can result in a measurable systemic inflammatory r esponse, providing further in vivo data to support a mechanistic relationsh ip between oral and systemic pathology.