Despite being considered noncritical size defects, extraction sockets often require the use of bone grafts or bone graft substitutes in order to facilitate a stable implant site with an aesthetically pleasing mucosal architecture and prosthetic reconstruction. In the present study, the effect of novel TiO2 scaffolds on dimensional ridge preservation was evaluated following their placement into surgically modified extraction sockets in the premolar region of minipig mandibles. After six weeks of healing, the scaffolds were wellintegrated in the alveolar bone, and the convex shape of the alveolar crest was preserved. The scaffolds were found to partially preserve the dimensions of the native buccal and lingual bone walls adjacent to the defect site. A tendency towards more pronounced vertical ridge resorption, particularly in the buccal bone wall of the nongrafted alveoli, indicates that the TiO2 scaffold may be used for suppressing the loss of bone that normally follows tooth extraction. 1. Introduction Oral rehabilitation with dental implants requires sufficient vertical and horizontal dimensions of the residual alveolar ridge in order to accommodate and fully embed the endosteal implants in alveolar bone [1, 2]. However, the dynamic hard tissue remodelling that occurs following tooth extraction typically results in significant resorption of the residual alveolar ridge, and the rate of this progressive postextraction bone loss has been shown to be fastest during the first three months [3, 4]. Since the loss of bone height and original ridge contour can lead to complications in implant placement, reducing the dimensional ridge alterations plays an important role in achieving mechanically stable and aesthetically pleasing clinical outcome in implant-retained prosthetic rehabilitation. Several clinical and preclinical studies have described the morphological changes occurring in the alveolar process in both apical-coronal and buccal-lingual directions following extraction of teeth [2, 3, 5, 6]. The healing sequence of an alveolar socket begins with the formation of a blood coagulum within the alveolus, which subsequently formed into a temporary matrix before osteoblastic reorganisation of the temporary matrix to woven bone [7]. Simultaneously, the socket walls undergo bone remodelling and osteoclastic resorption, and it has been shown that particularly the buccal aspect of the residual ridge is susceptible to reduction in bone volume [6]. It has been suggested that immediate implant placement in fresh extraction sockets can help maintain the original ridge
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