Flap versus flapless procedure for ridge preservation in alveolar extraction sockets: a histological evaluation in a randomized clinical trial

Objective: The aim of this study was to evaluate and compare the histological and histomorphometric features of two different procedures carried out in extraction socket grafting; namely, the flapped and flapless technique. Materials and methods: Patients considered eligible for the study were randomized to receive tooth extraction and ridge preservation with the porcine bone and collagen membrane, with a full thickness mucoperiosteal flap and primary soft tissue closure (control group), or, with a flapless procedure and a secondary soft tissue closure (test group). After 3 months of healing, the surgical re-entry procedure was performed and implants were inserted in the test as well as in the control sites. Bone core samples were harvested from both groups and processed to be observed under light microscopy. Outcome variables were percentages of newly formed bone, residual graft particles and marrow spaces. Results: Thirty-four patients were enrolled in the study. All of the scheduled implants were placed. Histological and histomorphometrical analyses did not report significant differences between the two groups (with P-values ranging from 0.690 to 0.917). The mean percentages of newly formed bone, soft tissues and residual grafted particles were 22.5 and 22.5%, 59.3 and 59.4%, and 18.6 and 18.2% respectively for flap and flapless approach. Conclusion: No histological and histomorphometrical differences were observed when comparing the flap and the flapless technique for tooth extraction and socket grafting procedures