The aim of this study was to determine the effects of high dose methotrexate in PL induced in rats molars and periapical region.
It was used 35 male Wistar rats. To induce PL, the pulps of first mandibular molars were exposed using a ½ round bur on a high-speed handpiece. It was expected 30 days. Then, 7 groups were formed with 5 animals in each one. G1: No induction of periapical lesions but with weekly intraperitoneal administration (WIPA) of saline solution (NaCl 0.9%) for 2 weeks and sacrifice after 2 days of last WIPA. The groups G2, G3 and G4 suffered periapical induction and WIPA of saline solution for 2 weeks being sacrificed 2.4 and 7 days respectively. The groups G5, G6 and G7 suffered periapical induction and WIPA of methotrexate (12 mg/kg/week) for 2 weeks, being sacrificed 2, 4 and 7 days respectively. CBCT was performed to measure the size of PL. A histomorphological analysis was also performed to determine the intensity of the inflammatory infiltrate and the presence of periapical bone resorption. Statistical analyzes used were ANOVA and Kruskall-Wallis test.
The size of periapical lesions in control and methotrexate groups showed no statistically significant difference (p = 0.2). PL were composed by chronic inflammatory reaction ranging from mild to moderate, predominantly of lymphocytes.
According to the data obtained, in the presence of persistent PL associated with the root canal, treatment with high doses of MTX did not influence the progression of these lesions.