Periodontal defects after third molar surgery: What is the risk of having periodontal defects on the distal of the mandibular second molar after third molar removal?

Data sourcesMedline was used to source studies for the review.Study selectionProspective studies were selected that had been published in English and had at least 6 months' follow-up data, which facilitated comparison of pre- and postoperative clinical periodontal measures of attachment levels (AL) or probing depths (PD) at the distal of the second molar.Data extraction and synthesisPerioperative changes in AL or PD were recorded. For studies reporting mean data, pre-operative and long-term follow-up measures were compared: changes in PD or AL >2 mm were considered clinically significant. For subject- or tooth-specific data, periodontal status was recorded as disease present (AL>2 mm; PD>4 mm) or disease absent. Pre- and postoperative conditions were compared using 2×2 tables to estimate number-needed-to-treat (NNT) or number needed to harm (NNH).ResultsEight studies (two prospective cohort studies and six randomised controlled trials) met the inclusion criteria. Mean data were recorded in five studies which, overall, showed clinically insignificant changes in AL/PD at the end of follow-up. Four studies, with sample sizes ranging from 10–24, allowed calculation of NNT and NNH. Where periodontal disease was present preoperatively, NNT ranged from 3–10. Periodontal health status worsened after third molar removal in 48% of cases, giving a NNH of 2.ConclusionsNo clinically significant changes in AL or PD were identified after third molar removal. In subjects who pre-operatively had a healthy second molar periodontium, there is an increased risk of worsening AL or PD after third molar surgery. © 2006 EBD.