Histologic analyses of flapless ridge preservation in sockets with buccal dehiscence defects using two alloplastic bone graft substitutes.

OBJECTIVES: To investigate whether one of two synthetic bone substitute materials used for ridge preservation in the extraction sockets with buccal dehiscence defects was superior regarding new bone formation and ridge preservation and to compare it to sites left for spontaneous healing. MATERIALS AND METHODS: In sixteen dogs, P3 and P4 were hemi-sectioned and the respective distal roots were extracted. Following the preparation of a mucoperiosteal flap without vertical releasing incisions, 50% of the buccal bone was carefully removed. The extraction sites were randomly assigned either to a ridge preservation procedure (alloplastic bone substitute material (two test groups)) or to spontaneous healing (control group). Descriptive histology and histomorphometric analyses were performed at healing times of 4, 8, and 16 weeks. In case of homogeneous variances, the results were analyzed by one-way ANOVA, followed by Tukey's post-hoc test. If inhomogeneous, the data was analyzed using Welch-type ANOVA, followed by the Games-Howell post-hoc test. RESULTS: The use of bone substitute material led to significantly greater horizontal dimensions amounting to 3.3 mm (SD = 0.67; test 1) and 3.5 mm (SD = 0.72; test 2) compared to spontaneous healing (1.7 mm, SD = 0.23) at 16 weeks of healing (p < 0.0001). A significant difference was observed between spontaneous healing and the test groups in terms of newly formed bone tissue at 4, 8, and 16 weeks (p = 0.001), with values reaching 7.9, 21.8, and 36.8% (test 1), 5.0, 10.4, and 29% (test 2), and 26.2, 43.5, and 56.4% (control), but there were no significant differences between the test groups (p > 0.05). The final ridge profile was more favorable after ridge preservation (p < 0.001) as demonstrated by a loss of 28.8% (spontaneous healing) and an increase in both test groups at 16 weeks (test 1 = 60.5% and test 2 = 31.2%). CONCLUSIONS: The use of alloplastic materials rendered greater horizontal dimensions and a more favorable maintenance of the ridge profile. CLINICAL RELEVANCE: Alloplastic bone substitute materials can successfully be used for ridge preservation procedures.