Biomechanical comparison of polylactide-based versus titanium miniplates in mandible reconstruction in vitro

Objectives: Evaluation of the mechanical integrity and reliability of polylactide-based miniplates for osseous free flap fixation at the mandible in an experimental study setup of a mandible reconstruction model. Material and methods: 1.0 mm titanium miniplates (group TI) (MatrixMandible, DePuy Synthes, Umkirch, Germany) and 1.5 mm polylactide miniplates (group PL) (Inion CPS, Inion Oy, Tampere, Finland) were used to fix a polyurethane (PU) fibula segment to a PU mandible reconstruction model using monocortical non-locking screws. Mastication was simulated via unilateral cyclic dynamic loading at 1 Hz with increasing loads (+ 0.15 N/cycle, Bionix, MTS, USA). A 3D optical tracking system (Aramis, GOM, Braunschweig, Germany) was used to determine interosteotomy movements (IOM). Results: IOM were higher in the polylactide group (distal: P = 0.001, mesial: P = 0.001). Differences in mean stiffness (titanium: 478 + 68 N/mm; polylactide: 425 + 38 N/mm, P = 0.240) and mean force at a vertical displacement of 1.0 mm (titanium: 201.6 + 87.1 N; polylactide: 141.3 + 29.9 N, P= 0.159) were not significant. Conclusions: The results of this study suggest that polylactide-based miniplates provide reduced mechanical integrity and higher interosteotomy movements in comparison to titanium miniplates in vitro. Indications for clinical use of polylactide-based miniplates in mandible reconstruction have to be placed critically. Future studies will focus on clinical complications of polylactide-based plates in risk patients. (C) 2019 Elsevier Masson SAS. All rights reserved.