The comparative biomechanics of the reinforced interdental crossover and the Stout loop composite splints for mandibular fracture repair in dogs

Objectives: To describe a new technique, the reinforced interdental crossover composite splint (RIC), for transverse mandibular fracture repair in dogs. This technique was compared biomechanically with the established reinforced interdental Stout loop composite splint (RIS) technique. Methods: Six pairs of mandibles from young adult small breed dogs were used for the study. Osteotomies were created in a standardized fashion and fixed with either RIC or RIS. All composite splint constructs were tested biomechanically with a cantilever bending force, using a single column testing machine at a rate of 2 mm/min. The time of application, amount of composite used, ultimate force, stiffness, total displacement, and total energy absorbed during displacement of the rostral mandibular segment were calculated and compared between the two groups. Results: No significant difference was found when comparing the time of application of the RIC and the RIS techniques. All implants failed by either composite resin fracture over the region of the osteotomy or by fracture between the first and second molar followed by detachment of the resin from the lingual enamel surface of the first molar. Differences between the RIC and RIS in force (80.5 N +/- 40.3 and 51.8 N +/- 27.4. respectively) and stiffness (16.2 N/mm +/- 4.4 and 10.1 N/mm +/- 4.1 respectively) were significant (p = 0.03). However differences between the two techniques in displacement and total energy absorbed were not significant. Clinical significance: In experimentally fractured mandibles of young adult dogs there is evidence that RIC is biomechanically similar to RIS