Interrelationship Between Physical Exercise and Apical Periodontitis in Trained Rats.

Objective: To assess the influence of physical exercise on apical periodontitis (AP) development, and the effect of AP on physical exercise capacity in exercise-trained rats. Materials and Methods: After animal Ethics Committee approval, 40 male Holtzman rats (9 weeks old) were distributed into the following four groups (n = 10/group): physical exercise without AP induction (Ex); physical exercise with AP induction (Ex-AP); sedentary without AP induction (S); sedentary with AP induction (S-AP). In trained groups, animals performed moderate-intensity aerobic training (treadmill) for 11 weeks. The maximal capacity test (T max) was performed at baseline (0 weeks), 8 and 11 weeks to analyse physical capacity and increase training velocity to maintain training intensity. In the AP-induced groups, coronal access of the left maxillary and mandibular first and second molars was performed after 8 weeks of training, and the pulp chamber was kept open for 21 days. After euthanasia, the hemi-mandible was submitted to histopathological, radiographical and micro-computed tomography (micro-CT) analyses to evaluate the inflammation, the area and the volume of periapical bone resorption, respectively. Results: The T max results of trained groups were higher than those of sedentary groups (p < 0.05). There was no difference in T max results between trained groups (Ex and Ex-AP; p > 0.05), or between sedentary groups (S and S-AP) (p > 0.05). Regarding volume and area of apical bone resorption, there was no difference between S-AP and Ex-AP (p > 0.05). Histopathological qualitative analysis also showed no differences between S-AP and Ex-AP. Conclusion: Physical exercise did not influence AP development, nor did AP affect physical exercise capacity in trained rats.