Biomechanical variables affect peri-implant bone loss in implant-supported fixed complete dentures: A methodological and prospective study.

Abstract

Implant-supported fixed complete dentures (IFCD) experience failures and complications related to biological and technical risk factors. This study investigated the effect of biomechanical variables of IFCD on 1-year peri-implant bone loss at the buccal, palatal/lingual, mesial, and distal implant sides. A new method was used to measure the geometric biomechanical variables of IFCD using cone beam computed tomography (CBCT). The study sample consisted of 246 external hexagon implants supporting 48 hybrid IFCD in 44 patients. CBCT images obtained immediately (T0) and 1 year (T1) after prosthesis installation were used to measure the support polygon area, clinical crown/implant (C/I) ratio (vertical lever), anteroposterior power and resistance arms, anterior and posterior cantilevers (horizontal levers), and peri-implant bone remodeling (T1-T0). Data were analyzed using multilevel multivariable models. The average total bone loss in the mandible and maxilla were 0.88 mm, with a loss of 0.62 mm in the mandible and 1.08 mm in the maxilla. The C/I ratio had a significant effect on bone loss on the mesial, distal, and palatal/lingual sides (P <.05). The anterior cantilever had a protective effect on the lingual side of the anterior implant. No effect on bone loss was found for the support polygon area, posterior cantilever, resistance arm, or power arm (P >.05). The results suggest that the C/I ratio and anterior cantilever in IFCD affect peri-implant bone loss according to the implant side and position in the arch.