Finite element analysis of masticatory stress on neoformed bone tissue after distraction osteogenesis and low-level laser therapy : a pilot study

Abstract

Objective: This study aimed to understand the action of masticatory forces on an implant virtually introduced into the sheep mandible after distraction osteogenesis and low-level laser therapy (LLLT) by using finite element analysis. Background data: Distraction osteogenesis as an alternative for bone reconstruction that may be used in the treatment of deformities. Methods: Four ewes underwent distraction osteogenis to elongate the left mandibular body by 15 m, and three of them underwent LLLT with the purpose of improving bone properties. After death, animals were scanned by computed tomography and their mandibles were tridimensionally reconstructed by computer programs. The physical properties related to hardness and modulus of elasticity of each animal were obtained from the dissected mandibles, and data were transferred to Femap software for finite element analysis. Results: Animals exposed and not exposed to LLLT irradiation showed remarkably similar values for superficial hardness and modulus of elasticity, without statistically significant difference ( p > 0.05), between the values observed for the cortical bone and the cancellous bone among the groups. The neoformed mandible, after a brief period for bone healing, was able to promote stability for implant placement and proper distribution of masticatory forces. Conclusions: An implant introduced virtually into the site of bone neoformation did not suffer any micromotions relevant to osteointegration. Furthermore, finite element analysis showed that the neoformed portion of the mandible was able to absorb and distribute masticatory forces throughout its structure, even after a brief period for bone maturation.