지르코니아 지대주의 두께에 관한 연구

Abstract

The purpose of this study is to evaluate optimal thickness of zirconia abutment for anterior implant restoration. This study was planned to perform two experimental stages. The fracture strength of zirconia abutment that fabricated by CAD/CAM system. For uniform replication of zirconia abutment, presintered zirconia were processed using CAD/CAM and then zirconia abutments were fabricated. Thickness of each zirconia abutments were 0.5mm, 0.8mm, 1.2mm, 1.5mm. In this study, Osstem US type implant fixture(external connection 4.0mm D, Osstem, Pussan, Korea). Zirconia abutment was constructed by replicating a cement abutment. Abutment was made by increasing the thickness of the sidewall and in order to maintain a certain form of finish line, emergence profile was increased as the thickness of the sidewall was increased. After completion of the zirconia abutment, zirconia crown to be setted temporarily on the upper part of abutment was constructed. Crown was made of 1.5mm thickness using CAD/CAM and cemented to abutment using RelyXTM UniCem(3M ESPE AG, Seefeld, Germany). After the specimen was fixed in the universal testing machine, fracture strength of zirconia abutment were measured in forcing on 45° angle.

1. Abutment fracture strength of Group 1, 2, 3, 4 was measured to be 236.00±67.55N, 599.00±15.80N, 588.20±33.18N, 597.83±98.13N.

2. Statistically significant differences were found between four groups(Kruskal-Wallis test, P<.05). In four groups, Group 1 showed statistically significant lower values than Group 2, Group 3, Group 4(independent Mann-Whitney U test, P<0.05). Any statistically significant difference was not found between Group 2, Group 3 and Group 4 (independent Mann-Whitney U test, P>0.05).

Judging by the results of this experiment, it was concluded that zirconia abutment should be at least 8mm or more to be applied in clinical practice.