Available evidence suggests little difference in outcomes between primary or secondary closure techniques after surgical removal of third molars


Classic wound closure following removal of impacted this molars involved the surgeon covering  and hermitically closes the socket with a flap, allowing primary wound healing. Proponents of  this approach suggest that it decreases the risk of post operative infection.  the alternative approach is to allow healing by secondary intention. Those who prefer this approach suggest that it allows drainage of inflammatory exudate, because the socket remains in communication. The aim of this review was to the impact of secondary versus primary closure techniques on the frequency and severity of pain, facial swelling, trismus, infectious complications, and postoperative bleeding after impacted mandibular third molar extraction.

What did they do

Searches of the Medline, Embase, Cochrane Central Register of Controlled Trials  CENTRAL  and International Clinical Trials Registry Platform Search Portal databases  and reference lists of the potentially eligible articles were conducted. Randomised controlled trials (RCTs) in adults comparing any type of surgical secondary closure technique were included. There  were no language restrictions. Study selection and data abstraction and risk of bias was carried out by two researchers independently.  Risk of bias was assessed using Cochrane criteria. with the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) rating system being used to evaluate confidence in the effect estimates (quality of evidence) across outcomes

What did they find

  • 14 studies were included
  • Pain and facial swelling at 3 and 7 and days postoperative and infectious complications at day 7 did not differ between techniques.
  • Patients receiving secondary closure had less trismus (in millimeters) at 3 days postoperative (mean difference, 3.72; 95% confidence interval, 1.42 to 6.03, P = .002) and 7 (mean difference, 2.35; 95% confidence interval, 0.37 to 4.33; P = .02).
  •  Four randomized controlled trials reported bleeding: in 2, there was no bleeding in either group; the numbers of bleeding events with primary and secondary closures were 22 and 16 and 5 and 15, respectively, in the other 2.

The concluded

Although differences between primary and secondary closure techniques after impacted mandibular third molar extraction are likely to be small, available evidence provides only low confidence in the effect estimates. The results do not support a preference for either approach.


This is a well conducted systematic review. However as the authors note,

trials were fraught with problems for risk of bias, inconsistency, and imprecision. Thus, they warranted only low to very low confidence in the estimates, leaving open the possibility that there could be substantial benefits for either technique.

There have been a number of systematic reviews published recently that we have blogged about covering aspects of the management of third molars and given that this is a very commonly performed procedure it  is somewhat disappointing that we do not have more robust evidence on which to base out management.


Carrasco-Labra A, Brignardello-Petersen R, Yanine N, Araya I, Guyatt G. Secondary Versus Primary Closure Techniques for the Prevention of Postoperative Complications Following Removal of Impacted Mandibular Third Molars: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Oral Maxillofac Surg.2012 Jun 11. [Epub ahead of print] PubMed PMID: 22695015.

GRADE (Grading of Recommendations, Assessment, Development, and Evaluation)

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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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