Shell technique using a rigid resorbable barrier system for localized alveolar ridge augmentation.

OBJECTIVES: To assess the safety and efficacy of a rigid synthetic barrier system in a shell technique for localized alveolar ridge augmentation. MATERIALS AND METHODS: Saddle-type defects (n = 4 each) were prepared in the lower jaws of six fox hounds. At two defects, the outer contours were reconstructed using polylactic acid (D and L isomers) (PDDL) pins welded to PDDL plates by ultrasound vibration and the defect area filled using either a natural bone mineral (NBM) or NBM + autogenous bone (AB) and covered by a native collagen membrane (CM). While the third defect was augmented using NBM+AB+CM, the fourth site was left untreated. At 14 weeks, dissected blocks were processed for histomorphometrical analysis [e.g., augmented area (AA)]. RESULTS: AA values (median in mm(2)) were significantly increased in all guided bone regeneration (GBR) groups [NBM+PDDL+CM (19.74) > NBM+AB+PDDL+CM (16.98) > NBM+AB+CM (16.66)] when compared with the untreated control sites (7.34). Histological analysis has pointed, in the absence of any foreign-body reactions, to biodegradation of both PDDL plates/pins and CM. CONCLUSIONS: (i) All GBR procedures investigated equally supported bone regeneration, (ii) the application of PDDL+CM may be associated with increased mineralized tissue MT and subsequently AA values than CM alone, and (iii) AB may not improve healing at NBM+PDDL+CM-treated sites.