Associated variables of peri-implant bone resorption for dental implants placed in the fibular reconstructed maxilla and mandible of patients with oral cancer: A retrospective clinical study

Statement of problem: Peri-implant bone resorption is a critical factor in evaluating the long-term success of dental implants. However, information regarding the difference in peri-implant bone resorption when implants are placed in microvascular fibula free (MFF) flaps is limited, and how jaw location may influence long-term peri-implant bone stability under functional occlusal loading over extended follow-up periods is unclear. Purpose: The purpose of this retrospective clinical study was to investigate the variables related to peri-implant fibular bone resorption under functional occlusal force between the jaws for at least a 12-year follow-up. Material and methods: During the 12-year functional occlusion loading period, a total of 1444 successful endosseous dental implants were analyzed, including 880 implants placed in the mandibular MFF flap and 564 implants placed in the maxillary MFF flap in 212 patients with oral cancer. The clinical crown-to-implant ratio (C/I) was estimated from the panoramic images for each participant from 2011 to 2023. The C/I rate distribution per follow-up year was shown as mean ±SD for both groups. A generalized estimating equation (GEE) assessed the association between an implant site with an MFF flap reconstruction and risk factors (year, age, sex) on peri-implant bone changes, with C/I change indicating the impact. Statistical analyses, including the Student t test, were performed using a statistical software program (SAS version 9.4). Results: A significant difference was found between the maxillary and mandibular C/I change (95% CI=0.086 to 0.7867; P=.014). Additionally, the time was closely related to the change in peri-implant bone level (95% CI=0.001 to 0.006; P=.003). Patient age also significantly affected the annual change in the peri-implant bone height; as the age increased by 0.016 years, the annual C/I change reduced by 0.005 (95% CI=−0.028 to −0.005; P=.007). Conclusions: Peri-implant bone resorption was found to be associated with the age, the duration of occlusal loading, and the location of the implant, either the MFF flap reconstructed maxilla or mandible. Implants placed in the MFF flap used to reconstruct the mandible had higher stability than those implants installed in the maxillary MFF flap under long-term occlusal loading.