2007 年 6 巻 3 号 p. 159-165
Purpose: The purpose of this study was to investigate the relationship between the number of splinted teeth and the effect of splinting on the movement of canines as abutments for maxillary distal-extension removable partial dentures.
Methods: A three-dimensional finite element method was used for the analysis. Abutments with normal bone height and with bone height lowered by 3 mm were prepared. The numbers of splinted teeth were two, three and six units. A load of 50 N or 200 N was applied in the vertical, buccal-oblique and lingual-oblique directions at the node corresponding to the buccolingual center of the mesial marginal ridge of the left first molar. Different material properties of the mucosa and periodontal ligament were used depending on the amount of loading. The ligament was defined as an orthotropic material.
Results: The results showed that horizontal displacement of the canine in the “two-unit splint” model was approximately one-third to one-half of that in the single abutment model. There was little difference in the horizontal displacement between the two-unit splint and “three-unit splint” models. In the “six-unit splint” model, the displacement was reduced to approximately half of that of the two-unit splint model. In all of the splinted models, the vertical displacement was reduced to approximately half of that of the single abutment model.
Conclusion: In the cases of reduced periodontal support or large and/or laterally directed occlusal force, abutments should be splinted. In cases of a coincidence of these unfavorable conditions, splinting six anterior teeth was recommended.
