Biomechanical influence of plate configurations on mandible subcondylar fracture fixation: a finite element study

Abstract

Mandible subcondylar fractures have very high complication rate, yet there is no consensus in a suitable plate design for optimal patient outcomes. The present study is aimed at understanding the subcondylar fracture fixation by comparing load transfer in intact and reconstructed fractured mandibles with five different plates: single mini, trapezoid, lambda, strut, and double-mini plates under the complete mastication cycle. Under contralateral molar occlusion (LMOL), the single mini plate resulted in the highest strains. On the contrary, during ipsilateral molar clenching (RMOL), the tensile and compressive strain distributions were found to be reversed, with the tensile strains at the posterior border resulting in lesser strain in reconstructed mandible with single mini plate. Owing to the reduced strains in the reconstructed mandibles, the contralateral molar clenching task is preferred during the immediate post-surgery period for patients. Under this contralateral molar clenching, the peak von Mises stresses in the plate decreased with increase in the number of screws. Furthermore, the presence of two arms seems beneficial to neutralise the tensile and compressive strains across load cases. Consequently, double mini and trapezoid plates were found to perform better as compared to single mini plate during the entire mastication cycle for subcondylar fracture fixation.

Biomechanical comparison of plate materials and designs for subcondylar fracture fixation: Anin silicoassessment

“…Thereafter, the plates were assigned with four different effective material properties, to investigate the influence of the materials on the load-transfer across the mandible. The methodology used for the development of the intact and reconstructed mandibles has already been discussed in detail elsewhere [22] and, therefore, is briefly presented here.…”

“…All the solid models of components, including the soft tissues, were discretized with a 10-noded tetrahedral element (SOLID 187) [24]. A 0.2 mm thick PDL layer was included due to the notable impact of the PDL on the load transfer from the teeth to the bone [22,25]. Two blocks representing the temporal bone were modelled with 20x15x15 mm 3 having a concave depression [25,26].…”

“…However, the influence of different materials, such as nitinol and less rigid Ti alloy and designs, has not been extensively studied. Moreover, recent studies on three designs and two materials [20], and double mini plates with four materials [21] used simplified FE models under idealised loading conditions without consideration of soft tissues Hence, we developed a FE model with periodontal ligament, condylar fibrous tissues, teeth, cancellous and cortical and simulated under a complete mastication cycle as a part of our earlier study [22,23]. However, our previous study [22] evaluated only Titanium implants and the influence of other implant materials was not considered.…”

“…Moreover, recent studies on three designs and two materials [20], and double mini plates with four materials [21] used simplified FE models under idealised loading conditions without consideration of soft tissues Hence, we developed a FE model with periodontal ligament, condylar fibrous tissues, teeth, cancellous and cortical and simulated under a complete mastication cycle as a part of our earlier study [22,23]. However, our previous study [22] evaluated only Titanium implants and the influence of other implant materials was not considered. This study uses the published mandibular FE model methodology [22] to further analyse the influence of both designs and materials of implants on the reconstruction.…”

“…However, our previous study [22] evaluated only Titanium implants and the influence of other implant materials was not considered. This study uses the published mandibular FE model methodology [22] to further analyse the influence of both designs and materials of implants on the reconstruction. This study aims to gain an insight into the interplay of material properties and plate design on parameters such as interfragmentary distance at the fracture site that indicates fixation stability.…”