CAD·CAM 기술을 이용하여 제작한 금속 코핑의 변연 및 내면 적합성 비교

Abstract

Purpose: The purpose of this in vitro study was to evaluate the marginal and internal adaptation of metal coping fabricated by four different CAD/CAM technologies. Methods: Mandibular right first molar was designed as the abutment in Dentiform model. The prepared artificial tooth was scanned and STL file were sent to the CAD.CAM centers to make metal die. After fabrication of metal die, die was scanned and metal coping was designed on the CAD software. STL file of designed coping image was sent to each laboratory to make different types metal coping. Four different techniques were used to fabricate the metal copings: Group MW (n=15): Milled wax and lost-wax casting process, Group RP (n=15): Resin RP and lost-wax casting process, Group MC (n=15): Milled Co-Cr block, Group DLMS (n=15): Direct laser metal sintering of Co-Cr powder. Fabricated copings were setting with temporary cement on the metal die. To measure the marginal and internal gap, Micro CT was taken and data was precess with the reconstruction software. Each nine points from midsection image of buccolingual direction and mesiodistal direction were measured using AutoCAD software. Mean and standard deviation of each measurement points were analyzed.

Results: In mean cement film thickness, Group MW showed smallest value and Group DLMS showed largest value. In marginal gap, Group MW showed smaller gap than other groups. In chamfer area, Group MW showed smaller gap and Group DLMS showed largest gap. In axial wall,there were no significant different between groups. Occlusal gap showed larger values than other measuring areas. Group MW showed significantly smaller gap than Group DLMS.

Conclusions: Metal copings which are fabricated by four different CAD/CAM technologies showed clinically acceptable marginal and internal fit. Therefore, those fabrication method can be used effectively for the metal cap fabrication of porcelain fused metal crown with several advantages. However, calibration and standardization of the scanner and manufacturing machine are needed for the more precise prostheses which have small deviation.