The Implant Surface and Its Role in Affecting the Dynamic Processes of Bone Remodeling by Means of Distance Osteogenesis: A Comparative In Vivo Study

Purpose: This study aimed to evaluate whether different surface modifications affect the dynamics of bone remodeling at the implant and the adjacent local bone. Materials and Methods: Seventy-two dental implants with different surfaces (smooth and rough control [smCtrl; rCtrl], smooth and rough + O₂-plasma spray [smPlas; rPlas], smooth and rough + nanocrystalline SiO₂-hydroxyapatite coating [ncSiO₂HA] + O₂-plasma spray [smNB-C; rNB-C]; each n = 12) were bilaterally inserted into the femora of 36 New Zealand white rabbits. Intravital fluorochrome labeling was performed to visualize the dynamics of bone formation. The objectives were quantification of bone-to-implant contact (BIC [%]) at 2 and 4 weeks and the dynamic bone formation (dbf [%]) at the implants' adjacent local bone within 1, 2, and 3 weeks. Results: After 2 weeks, BIC was significantly higher for both smNB-C (BIC: 59% ± 2% SEM) and rNB-C (BIC: 66% ± 3% SEM) compared with controls (BIC: 42% ± 1% SEM; P .005). After 4 weeks, BIC for rNB-C (65% ± 2%) was superior to all test groups (BIC: 39% ± 2% SEM; P = .012). Regarding dbf (%), neither within 1 (P = .88), 2 (P = .48), nor after 3 weeks (P = .36) did any differences occur among the groups, even in accordance to the implant level. Conclusion: Although distance osteogenesis seems crucial for the development of secondary stability, and thus, of osseointegration, it apparently is not affected by a bioactive ncSiO2HA surface coating. Changing the surfaces' release kinetics and composition may increase distance osteogenesis. Keywords: adjacent bone formation, distance osteogenesis, intravital labeling, ncSiO2HA-coating, secondary stability, surface modification