Influence of occlusal scheme on the pressure distribution under a completedenture

Purpose: The purpose of this study was to estimate which occlusion offers t he best conditions of pressure distribution on the supporting structure und er a complete denture when crushing food. Materials and Methods: Simulated maxillary and mandibular complete dentures with three different posterior o cclusal schemes-fully balanced occlusion, lingualized occlusion, and monopl ane occlusion-were fabricated. Eight pressure transducers were placed in th e basal surface of a mandibular denture. The pressure distribution on the m andibular edentulous mouth model with 1.5-mm-thick artificial tissue under a complete denture was recorded when crushing three different foods: soft f ood (kamaboko), peanuts, and carrot. The mean pressure values at each measu rement point and the force required for each test were compared using one-w ay analysis of variance with P less than or equal to 0.05 representing stat istical significance. Results: The required force for crushing a soft food or carrot in the left molar region in monoplane occlusion was significantly larger than that required in fully balanced occlusion or lingualized occlu sion. In crushing soft food, fully balanced occlusion showed significantly higher pressure values on the working side than in monoplane occlusion or l ingualized occlusion. In crushing the carrot, the pressure values in fully balanced occlusion and in lingualized occlusion were significantly lower th an those in monoplane occlusion. Conclusion: These results demonstrate that with fully balanced occlusion and lingualized occlusion a large occlusal f orce is not needed for crushing hard food, and the stress to the supporting tissues is smaller than with monoplane occlusion.