This study investigated whether long-term methylmercury exposure aggravates apical periodontitis in Wistar rats. Thirty-two male rats (90 days old) were randomized into four groups (n = 8): control, methylmercury, apical periodontitis, and methylmercury + apical periodontitis. Methylmercury was administered daily by intragastric gavage (0.04 mg/kg/day) for 60 days, while apical periodontitis was induced on day 32 by pulp expos...