Assessment of compression and strength of divergent screws mounted on miniplates and dynamic compression plate in fixation of mandibular body fractures: an in vitro study.

Abstract

Achieving compression in the fracture line gap by open reduction and internal fixation leads to more primary bone healing and therefore hastens the healing process and patient's rehabilitation. We aimed to evaluate the application of compression by a modification in screw insertion in miniplates to improve the efficiency of the previous relevant methods. In this in vitro experimental study 20 sheep hemimandibles were prepared. Following intentional fracturing of the hemimandibular bodies, the specimens were divided into two: the control and study groups (n=10 each). The control group was fixed with straight four-hole dynamic compression plate (DCP) without a bar and with parallel screws. The study group was fixed with a straight four-hole miniplate without a bar. Screws were divergently inserted into the bone with an angle of 45°. The differences in the fracture line gap were measured before and after fixation considering the indicators of compression. The strength of the fixation was also assessed with a universal testing machine. The control group provided more compression than the study group (p=0.4). There was no difference in the strength of fixation between the two groups. It is concluded that the application of the miniplates with divergent screws instead of DCP could encompass the advantages of both perspectives such as intraoral incisions and compressive force and prevent the disadvantages of compression plates such as hard adaptation.