Ｈｏｍｅ Ｐｏｓｉｔｉｏｎ診療姿勢がフィニッシング形態，特にフルショルダー形成へ及ぼす影響について 上顎左側第２小臼歯

Abstract

Abutment tooth of full shoulder with castable ceramic crown for the maxillar left second premolar (5) was prepared in Home Position (H.P.).The following results are obtained on the influence in H.P. on the finishing form, especially on the full shoulder preparation.1. Finishing Form 1) Angle of inclination of shoulder surface sloped in each part, especially on buccal.2) Width of shoulder was narrow in each part, except in medio-buccal and lingual.3) Surface of abutment tooth of lower part of axial wall and shoulder was rough in almost any part, except in central lingual.4) As for Rough Value, smooth of curve on finishing line was questionable, especially on each angles.2. Amount of Reduction1) Amount of reduction on the subgingival was small, especially on central-buccal and lingual.2) Taper of axil wall almost acceptable, excep cept central-buccal.3. Required Time for PreparationAbutment tooth preparation required about 18/20min. and the share of the stopping time of air turbine was about 35%. The preparation of medial and distal proximal surface and subgingival required longer time than any other part.This research clarified that taper of axial wall was almost acceptable in abutment tooth preparation of full shoulder in H.P., however, subgingival preparation of finishing form including finishing line was a subject to be solved.