Objective: The purpose of current study was to have comparison between the postoperative outcomes of triangular (wards) flap versus an envelope flap after surgical extraction of impacted mandibular third molar.

Methods: Current study was a double-blinded randomized controlled trial conducted at the Department of Oral & Maxillofacial surgery, Fatima Memorial Hospital, Lahore. Sixty patients were randomly recruited in two groups with random number table. Both groups consisted of 30 patients each. Among the patients of Group A, envelope flap was used for surgical access whereas patients of Group B received triangular flap for surgical access. Both Groups were followed on 2^nd and 7^th day postoperatively for pain status and trismus.

Results: Mean±SD of pain score at postoperative day 7th for group A was 23.47±6.75 and for group B it was 24.03±10.5 which was statistically insignificant (p>0.05). The difficulty index was found to have statistically significant (P<0.05) on 7th postoperative day pain. On the 7th postoperative day group A (envelope flap) had a mouth opening mean of 41.03mm and group B (triangular flap) which had a mean of 40.47mm which was statistically insignificant (p>0.05). The difficulty index was found to have statistically significant effect (P<0.05) on 7th postoperative day

Conclusion: The study concluded that there was no statistically significant difference between the two flap designs on postoperative pain and trismus while the difficulty of impaction was found to have statistically significant effect on postoperative pain and trismus

Keywords: envelope flap, triangular flap, trismus