Effect of Surgical Intervention for Removal of Mandibular Third Molar on Periodontal Healing of Adjacent Mandibular Second Molar: A Systematic Review and Bayesian Network Meta-Analysis.

BACKGROUND: The aim of this systematic review was to evaluate and synthesize scientific evidence on the effect of surgical interventions for removal of mandibular third molar (M3M) on periodontal healing of adjacent mandibular second molar (M2M). MATERIALS AND METHODS: The protocol (CRD42012003059) was registered on the International Prospective Register of Systematic Reviews (PROSPERO). Medline, Cochrane and Embase databases were interrogated to identify randomized controlled trials (RCTs) up to 22 December 2014. Patients with M3Ms fully developed, unilaterally or bilaterally impacted, were considered. Outcomes were clinical attachment level gain (CALg) and probing pocket depth reduction (PPDr) with a follow-up ≥ 6 months. Patient-subjective outcomes as pain, discomfort and complications, financial aspects and chair-time were also explored. A Bayesian network meta-analysis (NMA) model was used in order to estimate direct and indirect effects and to establish a ranking of treatments. RESULTS: 16 RCTs were included and categorized into 4 groups investigating: regenerative/grafting procedures (10 RCTs); flap design (3 RCTs); type of suturing (1 RCT); periodontal care of M2M (2 RCTs). Guided tissue regeneration (GTR) with resorbable (GTRr) and non-resorbable (GTRnr) membrane, and GTRr with anorganic xenograft (GTRr+AX) showed the highest mean ranking for CALg (2.99, 90%CrI: [1; 5]; 2.80, 90%CrI: [1; 6]; and 2.29, 90%CrI: [1; 6], respectively) and PPDr (2.83, 90%CrI: [1; 5]; 2.52, 90%CrI: [1; 5]; and 2.77, 90%CrI: [1; 6], respectively). GTRr+AX showed the highest probability of being the best treatment for CALg (Pr=45%) and PPDr (Pr=32%). Direct and Network quality of evidence rated from very low to moderate. CONCLUSIONS: At the best of our knowledge, the present review is the first one aiming to evaluate quantitatively and qualitatively the effect of different interventions on periodontal healing distal to second molar following extraction of third molar. GTR-based procedures with or without combined grafting therapies provide some adjunctive clinical benefit compared to standard non-regenerative/non-grafting procedures. However, the overall low quality of evidence suggests low degree of confidence and certainty in treatment effects. Evidence on variations of surgical M3M removal techniques based on flap design, type of suturing, and periodontal care of M2M is limited both qualitatively and quantitatively.