Efficacy of secondary vs primary closure techniques for the prevention of postoperative complications after impacted mandibular third molar extractions: A systematic review update and meta-analysis

Background: The aim of this systematic review was to determine whether secondary closure (SC) or primary closure (PC) is better at preventing postoperative complications after impacted mandibular third-molar extraction. Types of Studies Reviewed: The authors sought randomized controlled trials comparing the effects of PC and SC on pain, swelling, trismus, infection, and bleeding after impacted mandibular third-molar extraction. Screening, data extraction, and risk of bias assessments were conducted independently and in duplicate. The reviewers pooled results across studies using a random-effects meta-analysis and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. Results: This review identified 785 unique citations and included 40 trials. Compared with PC, SC was found to have trivial benefits for pain at day 7 and trismus within 1 week (moderate certainty). The incidence of infection and bleeding did not differ importantly between techniques (moderate certainty). However, SC is probably associated with less swelling on day 1 (standardized mean difference, –0.98; 95% CI, –1.22 to –0.73; moderate certainty) and day 3 (standardized mean difference, –0.87; 95% CI, –1.16 to –0.59; moderate certainty). There was very low certainty evidence for pain on days 1 and 3 and low certainty evidence for swelling on day 7. Conclusions and Practical Implications: Clinicians choosing between closure techniques should be aware that SC probably imparts an important benefit only for swelling at days 1 and 3. There seems to be a trivial difference between the techniques in other outcomes.