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A 3-dimensional accuracy analysis of chairside CAD/CAM milling processes


Bosch, Gabriel; Ender, Andreas; Mehl, Albert (2014). A 3-dimensional accuracy analysis of chairside CAD/CAM milling processes. Journal of Prosthetic Dentistry, 112(6):1425-1431.

Abstract

STATEMENT OF PROBLEM Milling is a central and important aspect of computer-aided design and computer-aided manufacturing (CAD/CAM) technology. High milling accuracy reduces the time needed to adapt the workpiece and provides restorations with better longevity and esthetic appeal. The influence of different milling processes on the accuracy of milled restorations has not yet been reviewed.
PURPOSE The purpose of this study was to investigate the influence of different milling processes on the accuracy of ceramic restorations.
MATERIAL AND METHODS Four groups of partial crowns were milled (each n=17): Three groups in a 4-axial milling unit: (1) 1-step mode and Step Bur 12S (12S), (2) 1-step mode and Step Bur 12 (1Step), (3) 2-step mode and Step Bur 12 (2Step), and (4) one group in a 5-axial milling unit (5axis). The milled occlusal and inner surfaces were scanned and superimposed over the digital data sets of calculated restorations with specialized difference analysis software. The trueness of each restoration and each group was measured. One-way ANOVA with a post hoc Tukey test was used to compare the data (α=.05).
RESULTS The highest trueness for the inner surface was achieved in group 5axis (trueness, 41 ±15 μm, P<.05). The 4-axial milling unit exhibited trueness at settings ranging from 61 μm (2Step) to 96 μm (12S). For the occlusal surface, the highest trueness was achieved with group 5axis (trueness, 42 ±10 μm). The 4-axial milling unit exhibited trueness at settings ranging from 55 μm (1Step) to 76 μm (12S).
CONCLUSIONS Restorations milled with a 5-axial milling unit have a higher trueness than those milled with a 4-axial milling unit. A rotary cutting instrument with a smaller diameter results in a more accurate milling process. The 2-step mode is not significantly better than the 1-step mode.

Abstract

STATEMENT OF PROBLEM Milling is a central and important aspect of computer-aided design and computer-aided manufacturing (CAD/CAM) technology. High milling accuracy reduces the time needed to adapt the workpiece and provides restorations with better longevity and esthetic appeal. The influence of different milling processes on the accuracy of milled restorations has not yet been reviewed.
PURPOSE The purpose of this study was to investigate the influence of different milling processes on the accuracy of ceramic restorations.
MATERIAL AND METHODS Four groups of partial crowns were milled (each n=17): Three groups in a 4-axial milling unit: (1) 1-step mode and Step Bur 12S (12S), (2) 1-step mode and Step Bur 12 (1Step), (3) 2-step mode and Step Bur 12 (2Step), and (4) one group in a 5-axial milling unit (5axis). The milled occlusal and inner surfaces were scanned and superimposed over the digital data sets of calculated restorations with specialized difference analysis software. The trueness of each restoration and each group was measured. One-way ANOVA with a post hoc Tukey test was used to compare the data (α=.05).
RESULTS The highest trueness for the inner surface was achieved in group 5axis (trueness, 41 ±15 μm, P<.05). The 4-axial milling unit exhibited trueness at settings ranging from 61 μm (2Step) to 96 μm (12S). For the occlusal surface, the highest trueness was achieved with group 5axis (trueness, 42 ±10 μm). The 4-axial milling unit exhibited trueness at settings ranging from 55 μm (1Step) to 76 μm (12S).
CONCLUSIONS Restorations milled with a 5-axial milling unit have a higher trueness than those milled with a 4-axial milling unit. A rotary cutting instrument with a smaller diameter results in a more accurate milling process. The 2-step mode is not significantly better than the 1-step mode.

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10 citations in Web of Science®
9 citations in Scopus®
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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Center for Dental Medicine > Clinic for Preventive Dentistry, Periodontology and Cariology
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:30 June 2014
Deposited On:20 Nov 2014 11:35
Last Modified:05 Apr 2016 18:31
Publisher:Elsevier
ISSN:0022-3913
Free access at:Official URL. An embargo period may apply.
Publisher DOI:https://doi.org/10.1016/j.prosdent.2014.05.012
Related URLs:http://www.zora.uzh.ch/100274/
PubMed ID:24993373

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