An in-vitro evaluation of a novel design of miniplate for fixation of fracture segments in the transition zone of parasymphysis-body region of mandible using finite element analysis

The mandibular parasymphysis and body regions are highly dynamic areas. They are constantly subjected to both occlusal and muscular forces. Fractures at this transition zone of the parasymphysis and body region thus represent a special pattern that creates a dilemma for the surgeons — whether to use one miniplate fixation or two miniplates as per Champy's guidelines. Mental nerve paresthesia is a very common complication due to dissection and stretching of the mental nerve in this region. Hence, an in-vitro research study of a novel twin fork design of miniplate is performed, which evaluates the biomechanical behavior using computerized finite element analysis. A comparison is carried out with the conventional design. The results show that the twin fork miniplate produces the lowest stresses — 23.821 MPa — and the least total structural deformation after applying the maximum occlusal bite force. This study concludes that the newly designed miniplate is superior in terms of stability because it shows the least structural deformation, and produces the lowest equivalent stresses on application of maximal occlusal forces. An additional advantage is the preservation of the mental nerve during the plating procedure because the broad end of the Y shape allows atraumatic positioning of the miniplate and hence the fixation of fractured segments.