Review Effect of Mechanical Debridement on Distal Periodontal Aspects of Second Molars After the Extraction of Third Molars: A Systematic Review Valeria Ramı ´rez,* Patricio Marro ´, † and Rodrigo Lo ´pez ‡ Background: The risk of periodontal defects after the extrac- tion of third molars continues to challenge clinicians. Methods: Intervention trials, including subgingival scaling and/or root planing, were systematically reviewed. Data sour- ces included the Cochrane Oral Health Group Trials Register and MEDLINE. The primary outcome was postoperative change in pocket probing depth (PD). Results: The electronic search yielded 751 abstracts, and manual searching added one study. From them, four trials ful- filled the inclusion criteria and were selected for review. The overall sample size of the studies was small, ranging from 15 to 30 participants. Only one trial was considered to present with low risk for bias in the sequence generation, the conceal- ment of allocation to treatment, and the strategy for masking. The lack of information provided by the authors of the remain- ing studies resulted in unclear or high risk of bias for the chief dimensions of trial quality. The heterogeneity of the studies did not allow the use of meta-analysis to summarize the results of several studies. Preliminary evidence originating from a small study suggests that ultrasonic root debridement of the second molar and a three-visit plaque control program may have a ben- eficial effect on PD levels on the second molar. Conclusion: The available intervention trials on this topic have important limitations, and, consequently, there is insuffi- cient evidence to recommend the use of mechanical debride- ment of second molars after the extraction of third molars. J Periodontol 2012;83:595-601. KEY WORDS Dental scaling; evidence-based dentistry; periodontitis; review. D estructive periodontal disease is a relatively common finding in relation to the presence of third molars, 1-4 and preliminary evidence suggests that this may affect non–third molars over time. 5 Although the occur- rence of periodontal disease before extraction of third molars has also been associated with complications after third- molar surgery, 6,7 the removal of man- dibular third molars may significantly improve the periodontal status of the distal aspects of second molars. 8-10 However, some studies have documen- ted that residual periodontal defects can be found frequently after surgical re- moval of impacted, lower third mo- lars. 11-13 It is unclear whether an eventual im- provement of the periodontal condition after third molar extraction could be en- hanced by mechanical debridement on the distal aspects of the second molars or whether the occurrence of residual dis- tal periodontal defects can be prevented by mechanical debridement of these sites after the extraction of third molars. The aim of the present systematic review is to assess the evidence on the effect of non-surgical subgingival me- chanical debridement and depuration on distal periodontal aspects of second molars after the extraction of third mo- lars. * Faculty of Dentistry, University of the Andes, San Carlos de Apoquindo, Santiago, Chile. † Hospital Dr. Jose ´ Horwitz Barak, Santiago, Chile La Paz, Santiago, Chile. ‡ Department of Periodontology, School of Dentistry, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark. doi: 10.1902/jop.2011.110462 J Periodontol • May 2012 595