Alveolar crest contour changes after guided bone regeneration using different biomaterials: an experimental in vivo investigation

Objective To evaluate the changes in alveolar contour after guided bone regeneration (GBR) with two different combinations of biomaterials in dehiscence defects around implants. Material and methods Chronic alveolar ridge defects were created bilaterally in the mandible of eight Beagle dogs. Once implants were placed, three treatment groups were randomly allocated to each peri-implant dehiscence defect: (i) test group received a bone substitute composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) covered by a cross-linked collagen membrane, (ii) positive control group with placement of deproteinized bovine bone mineral (DBBM) plus a porcine natural collagen membrane, and (iii) a negative control with no treatment. Two healing periods (8 and 16 weeks) were evaluated. Dental casts were optically scanned, the obtained files were uploaded into an image analysis software and superimposed to evaluate the linear changes. Results In both healing periods, the gains in linear contours were higher in the test group and at the intermediate level (3 mm below the gingival margin). While at 8 weeks, no significant differences were found between the groups; at 16 weeks, the test and positive control groups demonstrated significant gains in contour compared with negative control. Conclusions GBR using different biomaterials significantly increased the buccal contours of the alveolar crest when used at dehiscence defects around dental implants. Clinical relevance Particulate highly porous synthetic bone substitute and a cross-linked collagen membrane demonstrated similar outcomes in terms of contour augmentation when compared to bovine xenograft (DBBM) and a collagen membrane.