Bacteremia and the Systemic Host Response following Toothbrushing in Adults

Infection and inflammation are fundamental mechanisms linking oral-systemic diseases. Objective: To use a modified Experimental Gingivitis Model to determine whether plaque accumulation results in bacteremia and subsequent systemic inflammatory responses following toothbrushing. Methods: 24 healthy adults, 18-30 years gave written informed consent to participate. After dental prophylaxis and oral hygiene (OH) instructions, subjects performed OH for 7days (control phase), ceased OH for 7days (experimental phase), and resumed OH for further 7days (recovery phase). Plaque and gingival inflammation were assessed using the Plaque Index (PI) and Gingival Index (GI). Peripheral venous blood samples were collected at each visit to evaluate systemic markers of infection and inflammation including bacteremia, complete blood count, and neutrophil function. At the end of the experimental phase, subjects performed supervised toothbrushing. Peripheral blood samples were collected immediately before (baseline), 0.5mins, 5mins, and 30mins after toothbrushing. Additional blood samples were collected 4hrs after toothbrushing to assess serum IL-6 and IL-8 levels. Changes in values were analyzed using repeated measures ANOVAs. RESULTS: 21 subjects completed the study. The correlation between changes in PI and GI was 0.86. During the experimental phase, PI and GI increased significantly (p<0.05) as compared to the control and recovery phases. Three subjects were bacteremic 0.5mins following toothbrushing and one subject was bacteremic 30mins following toothbrushing. Bacterial isolates comprised Veillonella, Corynebacterium, and Fusobacterium species. Immediately following toothbrushing, total white blood cell and neutrophil counts increased significantly (p<0.05) as compared to baseline. These counts decreased significantly (p<0.05) during the recovery phase when compared to the experimental phase immediately following toothbrushing. Conclusions: Toothbrushing, when performed where there was already dental plaque accumulation, elicited bacteremic episodes and systemic inflammatory responses that may be of importance in understanding mechanistic pathways mediating oral-systemic diseases. This is the first study demonstrating the immediate systemic host response to bacteremia. Supported by NIH#R01DEO15145-01.