Mechanics in the Production of Mandibular Fractures: Strain-Gauge Measurements of Impacts to the Chin

¹ Department of Anatomy, The University of Michigan, Ann Arbor, Michigan, and Department of Engineering Mechanics, Wayne State University, Detroit, Michigan

Impacts to individual mandibles with a variety of condylar supports using SR4 strain gauges in the lateral subcondylar regions and lingual cortical plates have revealed quantitative results. These data indicate that the subcondylar region, in general, is exhibiting higher tensile and compressive strains than the lingual cortical plate and that the exact amount of these strains is dependent upon the individual bone. General trends were noted wherein higher strains were found in certain localities under certain types of impact and condylar fixations from specimen to specimen. Additionally intact cadaver heads were impacted on the chin, and here the strain-gauge readings generally showed a high tensile strain in the subcondylar regions, with lower readings from the lingual aspect of the chin.

These data confirm previous strain-sensitive-lacquer results indicating that these are the high-tensile-strain areas and also agree with certain previous clinical findings.