Alveolar Ridge Regeneration With Open Versus Closed Healing in Damaged Extraction Sockets: A Preclinical In Vivo Study

The objective of this study was to compare open versus closed healing of soft and hard tissue following alveolar ridge preservation (ARP) procedures in damaged extraction sockets. ARP was performed in five mongrel dogs using collagenated deproteinized bovine bone mineral (cDBBM) and a resorbable non-cross-linked collagen membrane (NCCM) in damaged extraction sockets, with each socket entrance left either open (open group) or closed (closed group). Clinical wound epithelization at the socket entrance and the dimensions of keratinized tissue were evaluated over time. Additionally, the augmented ridge dimensions and new bone formation were assessed radiographically and histologically at 8 weeks after surgery. The dimensions of the socket entrance gradually decreased in the open group, and wound epithelization was almost complete within 4 weeks. The mucogingival junction was maintained more apically in the open group than in the closed group (0.14 ± 0.40 mm vs. -0.86 ± 0.71 mm [mean ± SD], p 0.05). Histological analyses revealed no significant differences in the amount of newly formed bone. However, membrane resorption in the crestal region was more pronounced in the open group. Open and closed healing approaches for ARP in extraction sockets with damaged buccal wall resulted in similar ridge dimensions and new bone formation. However, there was less reduction of the buccal bone crest and wider keratinized tissue width after open healing.