Histological and dimensional changes of the alveolar ridge following tooth extraction when using collagen matrix and collagen-embedded xenogenic bone substitute: A randomized clinical trial.

AIM: To assess the horizontal and vertical dimensional changes of the alveolar ridge when using a collagen matrix in combination with collagen embedded xenogenic bone substitute, in comparison with natural healing after tooth extraction. METHODS: Patients that required extraction in non-molars areas were included. Test group-15 sockets were treated with deproteinized bovine bone mineral containing 10% collagen (DBBM-C), covered by a procaine collagen membrane (CMXs). Control group-15 sockets left for spontaneous healing. We used a custom-made acrylic stent as a reference for alveolar ridge measurements. Six-month postoperative, a single implant was placed in the experimental site. A core biopsy was taken from the site, using a trephine bur. Histomorphometric analysis assessed bone area, connective tissue, bone marrow, and residual bone graft. RESULTS: Six months later, horizontal ridge width at -3 mm showed a significant (p < 0.05) reduction in both groups albeit smaller in the test group 1.19 +/- 1.55 mm, compared with the control 2.27 +/- 1.52 (p = 0.087). At -5 mm sub-crestally, statistically non-significant reduction was noted in both groups, 1.61 +/- 1.53 and 1.96 +/- 1.52 mm for the test and control groups, respectively (p = 0.542). Vertical changes were smaller in the test group (0.14 +/- 1.84 mm) compared with control (0.98 +/- 1.49 mm). Keratinized tissue (KT) width was 7.3 +/- 2.13 and 7.5 +/- 3.49 mm in the test and control groups, respectively. Newly formed bone occupied 33.79 +/- 17.37% and 51.14 +/- 23.04% in the test and control groups, respectively, (p = 0.11). Connective tissue volume was 33.74 +/- 13.81% and 30.12 +/- 18.32% in the test and control groups, respectively (p = 0.65). Bone marrow occupied 19.57 +/- 10.26% and 18.74 +/- 17.15% in the test and control groups, respectively (p = 0.91). Residual graft occupied 12.9 +/- 9.88% in the test group. CONCLUSION: Alveolar ridge preservation using DBBM-C resulted in reductions of the vertical and horizontal dimensions albeit not reaching statistical significance. The larger than anticipated standard deviation and smaller inter-group differences might account for this phenomenon.