RESUMEN
OBJECTIVE: To investigate the effect of raising a mucoperiosteal flap on trismus and pain after extraction of an impacted lower third molar. STUDY DESIGN: We studied a consecutive series of 218 patients, all of whom underwent removal of an impacted lower third molar. Of the 218 patients, 52 (group A) underwent simple extraction without raising a mucoperiostal flap, 17 (group B) underwent extraction with raising of a mucoperiostal flap but without ostectomy, and 149 (group C) underwent extraction with both raising of a mucoperiostal flap and ostectomy (C). Trismus was evaluated as maximum interincisal distance (MID), determined before surgery and 1 and 5 days after surgery (MID0, MID1 and MID5 respectively). Pain was evaluated on the basis of reported analgesic use, likewise 1 and 5 days after surgery. RESULTS: In group A (no flap), there was no significant diference between MID0 and MID5; however MID1 was significantly lower than MID0. In groups B and C (flap), the difference between MID0 and MID1 was more marked, and in addition MID5 remained significantly lower than MID0. Neither MID0 nor MID5 differed significantly between group B (flap, no ostectomy) and group C (flap plus ostectomy). The proportion of group A subjects reporting analgesic use was significantly lower than the corresponding proportions in groups B and C on both day 1 and day 5, and again there were no significant differences between groups B and C.