C-reactive protein and serum amyloid A in a canine model of chronic apical periodontitis.

Increased levels of systemic inflammatory markers have been observed in patients with chronic dental diseases, such as marginal periodontitis. A canine model was used to determine if a systemic inflammatory response was evident during chronic apical periodontitis (CAP). Dental pulps in 10 dogs were exposed and infected with dental plaque to induce CAP. Blood samples were drawn preoperatively and postinfection when CAP was seen radiographically. In three of the 10 dogs, an intravenous challenge of Porphyromonas gingivalis A7436 was given subsequent to the development of CAP. An ELISA assay was used to measure the levels of C-reactive protein (CRP) and serum amyloid A (SAA) as markers of systemic inflammation. During CAP the levels of CRP and SAA were not statistically different from the preoperative values as determined by the Friedman test (p < 0.05). One dog, which had an unplanned trauma-induced laceration of the paw 2 days before blood sampling, showed a 40-fold increase in CRP. The 3 dogs challenged by intravenous P. gingivalis A7436 showed elevated levels of CRP, consistent with an acute phase response. These data demonstrate that the canine model provides a useful means for studying the systemic effects of apical periodontitis, and show that CAP is not associated with elevated CRP or SAA.