Can Implant-Retained Fixed Prostheses Trigger Bone Response in the Posterior Region of Edentulous Mandibles? A 32-Month Cone-Beam Computerized Tomography Study Analyzing Bone Height and Density

Abstract

Research has shown that the presence of implants can revert bone resorption and thus contribute to a greater preservation of the residual bone ridge, especially in edentulous mandibles. Bone remodeling has yet to be extensively studied in the context of prosthetic options for edentulous arches. This study aims to evaluate the long-term behavior of bone tissue in the posterior region of edentulous mandibles rehabilitated with implant-retained fixed prostheses using cone-beam computerized tomography (CBCT). Selected individuals were rehabilitated with 5 external hexagon platform implants and an implant-retained fixed prosthesis. The CBCT scans were performed immediately after surgery and after 8, 22, and 32 months (T0, T8, T22, and T32, respectively). Implants were installed between the mental foramen. Subsequently, bone crest height and density were measured in the posterior region of the mandible on the images in 3 distinct areas at 5, 10, and 15 mm from the center of the distal implant axis. Analysis of variance and the Bonferroni post hoc test were used for multiple analyses. The results indicate a statistically significant difference in bone height between T0 and all subsequent times; the bone height at T32 was 8.85% higher than at T0 (P = .05). There was a difference in bone height between all analyzed regions. The bone growth difference between the 5-mm and 15-mm positions was 28.42% after 32 months (P = .00). A significant increase of 5.76% in bone density was observed between T0 and T22 (P = .03). Within the limitations of this study (sample size, follow-up duration), it was demonstrated that the use of implant-retained fixed prostheses in the mandible resulted in qualitative and quantitative bone growth (bone preservation) in the posterior region of the mandible. Further research is needed to identify the validity of our findings for other populations and to determine the duration of the bone-remodeling process in rehabilitated edentulous mandibles.