Healing following GTR treatment of bone defects distal to mandibular 2nd molars after surgical removal of impacted 3rd molars

Aim: The purpose of this study was to study the healing, following guided tissue regeneration (GTR) treatment, of bone defects distal to mandibular 2nd molars (M2s) after surgical removal of impacted mesioangularly or horizontally inclined third molars (M3s) in patients greater than or equal to 25 years. Method: 20 patients with bilateral soft tissue impacted M3s were included in the split-mouth study. The 2 sites to be treated in each patient were randomised before the Ist operation as to which would undergo the test procedure and which would be the control site. After surgical removal of M3 at test sites, a resorbable polylactic acid (PLA) barrier was attached to M2 to cover the post-surgical bone defect. The flap was then replaced and sutured to cover the barrier. Control sites underwent the same procedure, as did the test sites, with the exception that no barrier was placed. The clinical examinations performed were oral hygiene pre- and 12 months postoperatively and probing pocket depth 12 months postoperatively. The alveolar bone level (ABL) at the distal surface of the M2, as determined from radiographs taken at suture removal and 12 months postsurgery, was chosen to be the primary response variable. Results. Most bone defects showed healing up to 10%-20% of the tooth length at both test and control sites. 2 test and 2 control sites showed no improvement in the bone level. The mean values of bone healing registered in mm from the cemento-enamel junction (CEJ) were 2.6+/-2.19 SD and 3.0+/-2.20 SD for test and control sites, respectively. Different factors affecting the healing result are discussed.