Analysis of abutment teeth in partially edentulous patients.

The aim of the study was to examine changes in the position of the abutment teeth (AT), size of undercuts for a denture clasp, as well as an existence of an adequate preparation of abutment teeth. A total of 156 casts of partially edentulous jaws, with 460 AT, were analyzed. The size of undercuts, a degree of abutment rotation, inclination and migration were measured using a dental parallelometer. The abutment teeth position was related to the level of occlusal plane in a dental articulator. Furthermore, the existence of an adequate preparation of abutment teeth, as well as a type of a denture and a type of a denture retention element were also considered. Analysis were carried out twice on casts made from a hard stone, the first time before the denture treatment had begun and the second time on the new casts obtained after new dentures had been delivered. The first analysis (prior dental treatment) revealed that a total of 33.9% of the analyzed AT were rotated, 31.3% were inclined, 12.1% had migrated, and 57.3% were elongated above the occlusal plane. On the casts obtained after the new dentures had been made, it was observed that none of the AT had an adequate preparation. Only 37.6% of all retention elements were located in adequate undercut positions on the AT. Upon the results of the present study a conclusion can be established that many abutment teeth are rotated, elongated, inclined, and migrated, which point to a requirement for AT preparation prior the manufacture of new denture; however none of the AT was adequately prepared considering insertion plane and many denture elements were located in an inadequate undercut size.