Trueness of milled prostheses according to number of ball-end mill burs

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• 作者：Chong-Myeong Kim ; MSc ; PhD^a ; So-Ri Kim ; MSc ; PhD^b ; Ji-Hwan Kim ; MPH ; PhD^c ; Hae-Young Kim ; DDS ; PhD^d ; Woong-Chul Kim ; MPH ; PhD^e ; ^{kuc2842@korea.ac.kr" class="auth_mail" title="E-mail the corresponding author}
• 刊名：The Journal of Prosthetic Dentistry
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：115
• 期：5
• 页码：624-629
• 全文大小：1922 K

文摘

Making a computer-aided design/computer-aided manufacturing (CAD/CAM) prosthesis with a milling machine often requires 2 (2- and 1-mm diameter) or 3 (2-, 1-, and 0.6-mm diameter) burs; however, using 3 burs can reduce time effectiveness and increase cost. Studies evaluating the trueness of prostheses made with 2 and 3 burs are lacking.

Purpose

The purpose of this in vitro study was to evaluate the 3-dimensional trueness of crown prostheses made using 2 and 3 ball-end mill burs in the milling process.

Material and methods

The abutment die of the maxillary right first molar for ceramic crowns was designed with computer-aided design software. After the crown prosthesis design was completed, polyurethane blocks were milled using 2 and 3 burs with a 5-axis milling machine. The outer and inner surfaces of the milled crown prostheses were scanned with a dental scanner. The inner part was separated into a marginal part and an internal part using 3-dimensional evaluation software. The 3-dimensional trueness of the prostheses milled with 2 or 3 burs was compared.

Results

No significant differences in trueness were found for the inner or internal parts of the prosthesis (P>.05). However, the outer and marginal parts of the prosthesis did show significant differences in trueness (P<.05).

Conclusions

Milling the marginal part of the inner prosthesis was better with 2 burs, whereas milling the outer part was better with 3 burs.