Can hard and/or soft occlusal splints reduce the bite force transmitted to the teeth and temporomandibular joint discs? A finite element method analysis

Abstract

ABSTRACT Objective To test whether two different materials used for occlusal splints would reduce the stress to the temporomandibular joint discs. Methods Geometric data from a young-adult male patient were obtained from computed tomography and magnetic resonance imaging. 3D biomodels and the finite element analyses were performed using specific software. Results The mandibular model presented the highest bone stress areas in the mandibular rami and insertion of the temporalis muscles. Regardless the material, the highest stress in the occlusal splints was located in the second molar regions on the occlusal splint surface and in the opposing mandibular second molars. Stress reduction was only observed in the internal surface of the occlusal splints embracing the maxillary teeth. No differences between occlusal splints were found in the stress intensity and distribution in either left or right TMJ discs, being concentrated more in the anterior portion of the disc. Discussion Hard acrylic OS should be preferred over soft EVA OS in the majority of cases, soft OS only for temporary use. Thinner OS (2–3 mm anterior thickness) should be preferred over thick ones (3–4 mm) in order to keep the stress concentrations in the center of the TMJ discs. Lighter contacts over heavier contacts should be preferred in the second molar OS contact surface area to prevent stress concentrations and fractures. Maxillary occlusal splints should be chosen if the teeth or implant are in the maxilla, and vice-versa.