This study evaluated the use of bone ring technique with xenogeneic bone grafts in treating horizontal alveolar bone defects. In total, 11 patients in need of horizontal bone augmentation treatment before implant placement were included in this retrospective study. All patients received simultaneous bone augmentation surgery and implant placement with xenogeneic bone ring grafts. We evaluated the postoperative efficacy of the bone ring technique with xenogeneic bone grafts using radiographical and clinical parameters. Survival rates of implants were 100%. Cone-beam computed tomography revealed that the xenogeneic bone ring graft had significantly sufficient horizontal bone augmentation below the implant neck platform to 0 mm, 1 mm, 2 mm, and 3 mm. It could also provide an excellent peri-implant tissue condition during the 1-year follow-up after loading. The bone ring technique with xenogeneic bone ring graft could increase and maintain horizontal bone mass in the region of the implant neck platforms in serious horizontal bone defects.

An odontogenic keratocyst (OKC) is a common oral cyst arising from the odontogenic epithelium, which has the characteristics of a tumor. Previous studies have demonstrated that M2-polarized macrophages and angiogenesis have important roles in the progression of OKCs. As transforming growth factor (TGF)-β1 is important in growth and developmental processes, and early studies have indicated that TGF-β1 is upregulated in OKCs, the present study aimed to investigate the expression levels of TGF-β1 as a first step. Flow cytometric analysis suggested that TGF-β1 induced M2-polarization of macrophages in a dose-dependent manner. Expression levels of cyclooxygenase (COX)-1 and-2 were measured after treatment of M2 macrophages with TGF-β1 and OKC homogenate supernatant. COX-2 expression was influenced by TGF-β1 in a concentration-dependent manner and in OKC induction. In addition, inhibition of COX-2 resulted in the induction of M2-polarization of macrophages via TGF-β1 and OKC disruption. Because the extracellular matrix (ECM) is altered in individuals with chronic diseases, the present study analyzed the expression of matrix metalloproteinase (MMP)-9, which is able to degrade the ECM. The present study observed a decrease in MMP-9 activity following treatment with TGF-β1 and OKC homogenate supernatant. Additionally, the present study analyzed tube formation caused by OKC with or without a COX-2 inhibitor. The results of the present study suggested that angiogenesis increased following treatment with OKC homogenate supernatant but decreased after treatment with a COX-2 inhibitor. These findings indicated that the TGF-β1/COX-2 pathway may have an important role in the progression of OKC.