A Synthetic Bio-Absorbable Membrane in Guided Bone Regeneration in Dehiscence-Type Defects: An Experimental In Vivo Investigation in Dogs

This study aimed to determine the performance and characteristics of a synthetic barrier membrane of polylactic acid and acetyl butyl citrate (PLAB) for the lateral bone augmentation of peri-implant dehiscence defects (mean height x depth = 3 mm x 1 mm). In eight dogs, three treatment groups were randomly allocated at each chronic peri-implant dehiscence-type defect: (i) a deproteinized bovine bone mineral covered by a synthetic barrier membrane (test group), (ii) a deproteinized bovine bone mineral covered by a natural collagen membrane (positive control), and (iii) a synthetic barrier membrane (negative control). After 4 and 12 weeks of submerged healing, dissected tissue blocks were processed for calcified and decalcified histological analysis. Histometric measurements for tissue and bone width were performed, and bone-to-implant contact and alkaline phosphatase expression where measured. After 4 and 12 weeks of healing, no statistical differences between the groups were observed for the histometric measurements. The expression of alkaline phosphatase was higher in the positive control group after 4 weeks followed by the positive and negative controls (5.25 & PLUSMN; 4.09, 4.46 & PLUSMN; 3.03, and 4.35 & PLUSMN; 2.28%, p > 0.05) and 12 weeks followed by the negative and positive controls (4.3 & PLUSMN; 2.14, 3.21 & PLUSMN; 1.53, and 2.39 & PLUSMN; 1.03%, p > 0.05). Concerning the bone-to-implant contact, after 4 weeks, the test group obtained the highest results (39.54 & PLUSMN; 48.7) vs. (31.24 & PLUSMN; 42.6) and (20.23 & PLUSMN; 36.1), respectively, while after 12 weeks, the positive control group obtained the highest Bone to imaplant contact (BIC) results, followed by the test and negative controls, (35.91 & PLUSMN; 24.9) vs. (18.41 & PLUSMN; 20.5) and (24.3 & PLUSMN; 32.1), respectively; no statistically significant differences were obtained. Within the limitations of the study, new bone formation can be achieved in guided bone regeneration procedures simultaneously with implant placement either with the use of a PLAB membrane or a native collagen membrane, although these differences were not statistically significant.