Biomechanical evaluation of two plating systems for fixation of mandibular condylar process fractures in dogs demonstrates sustainability under bite forces.

OBJECTIVE

To determine the biomechanical strength of 2 different condylar titanium plating systems (trapezoid and lambda condylar plates) in medium- to large-breed dogs for repair of mandibular condylar fractures under physiologic bite forces.

METHODS

An experimental study design was utilized in which mandibular condylar process fractures were simulated in medium- to large-breed adult dog cadaver heads. The selected implant was applied to the simulated fracture. The jaws were loaded in a load-to-failure test simulating a bite on a unilateral object while measuring bite force.

RESULTS

In 12 dog cadaver specimens, all constructs failed at simulated bite forces greater than expected physiologic bite force (600 N). The mean (SD) force to failure was 1,006.5 N (344.7) for the lambda plates and 847.8 N (78.0) for the trapezoid plates. There was no statistically significant difference in mean force to failure when comparing the different types of plates. Some degree of screw pullout occurred in 50% of specimens tested with the trapezoid plates. There was no significant difference in mode of failure between the 2 groups. The most common mechanism of failure was breakage of the loading apparatus.

CONCLUSIONS

Both condylar lambda plates and trapezoid plates sustain expected physiologic bite forces in domestic dogs after implantation. There is no significant difference in the force to failure for either type of implant.

CLINICAL RELEVANCE: These data support that both lambda condylar plates and trapezoid plates are suitable for open reduction and internal fixation of mandibular condylar process fractures in medium- to large-breed dogs.