Trueness of four different milling procedures used in dental CAD/CAM systems

Kirsch, Corinna; Ender, Andreas; Attin, Thomas; Mehl, Albert

doi:10.1007/s00784-016-1916-y

Cited by 85 publications

(80 citation statements)

References 29 publications

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“…In fact, milling is the most commonly used manufacturing process. For CAM, a five-axis milling unit can produce prostheses more accurately than a four-axis machine can [11][12][13]. With a five-axis milling machine, it is possible to mill pointed angles more accurately, given that a wider range of milling with a greater number of axes relative to the four-axis can be used [11,14].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Trueness of the Inner Surface of Crowns Fabricated from Three Types of Lithium Disilicate Blocks

Lee

Yoon

et al. 2019

Applied Sciences

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This study set out to compare the three-dimensional (3D) trueness of crowns produced from three types of lithium disilicate blocks. The working model was digitized, and single crowns (maxillary left second molar) were designed using computer-aided design (CAD) software. To produce a crown design model (CDM), a crown design file was extracted from the CAD software. In addition, using the CDM file and a milling machine (N = 20), three types of lithium disilicate blocks (e.max CAD, HASS Rosetta, and VITA Suprinity) were processed. To produce a crown scan model (CSM), the inner surface of each fabricated crown was digitized using a touch-probe scanner. In addition, using 3D inspection software, the CDM was partitioned (into marginal, axis, angular, and occlusal regions), the CDM and CSM were overlapped, and a 3D analysis was conducted. A Kruskal–Wallis test (α = 0.05) was conducted with all-segmented teeth with the root mean square (RMS), and they were analyzed using the Mann–Whitney U-test and the Bonferroni correction method as a post hoc test. There was a significant difference in the trueness of the crowns according to the type of lithium disilicate block (p < 0.001). The overall RMS value was at a maximum for e.max (42.9 ± 4.4 µm), followed by HASS (30.1 ± 9.0 µm) and then VITA (27.3 ± 7.9 µm). However, there was no significant difference between HASS and VITA (p = 0.541). There were significant differences in all regions inside the crown (p < 0.001). There was a significantly high trueness in the angular region inside the crown (p < 0.001). A correction could thus be applied in the CAD process, considering the differences in the trueness by the type of lithium disilicate block. In addition, to attain a crown with an excellent fit, it is necessary to provide a larger setting space for the angular region during the CAD process.

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Section: Introductionmentioning

confidence: 99%

Comparative Study of the Trueness of the Inner Surface of Crowns Fabricated from Three Types of Lithium Disilicate Blocks

Lee

Yoon

et al. 2019

Applied Sciences

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“…The aforementioned fully digital restorative workflow is meant to avoid the error-prone multistep process of conventional impressions, gypsum cast production, extraoral digitalization, 7 and conventional manufacturing of dental crowns by using a more standardized, reliable, and predictable approach. [8][9][10] However, this workflow is not exempt from errors, and inaccuracies that may arise during its execution [11][12][13][14] will have a cumulative effect throughout the production process, and if not controlled, threshold values [15][16][17][18][19][20][21][22][23][24][25][26][27] for the marginal and internal fit of dental restorations could be crossed, compromising the biological, esthetic, and mechanical success of such restorations. [28][29][30][31] Unfortunately, there is no consensus on what constitutes a clinically acceptable marginal and internal misfit.…”

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confidence: 99%

Marginal and Internal Fit of CAD/CAM Crowns Fabricated Over Reverse Tapered Preparations

Mejía

Yatani

Wakabayashi

et al. 2017

Journal of Prosthodontics

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“…Also, nine different milling machines were named in the studies and five studies failed to mention what machine was used. The choice of milling machine may affect the fit of restorations, Kirsch et al compared five-, and four-axis milling machines and found higher trueness in machines with five-axes [34]. Regarding the zirconia materials used in the studies, eleven different zirconia materials were found and four were not disclosed.…”

Section: Ios Systemmentioning

confidence: 99%

A systematic review on the accuracy of zirconia crowns and fixed dental prostheses

Svanborg

2020

Biomaterial Investigations in Dentistry

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Purpose: The aim of this study was to review the fit and assess the accuracy of tooth-supported single and multi-unit zirconia fixed dental prostheses. Background: The fit of zirconia restorations has been reported in several studies, but the accuracy of the manufacturing process is seldom discussed or used when drawing conclusions on the fit. Materials and methods: A literature search of articles published in PubMed between 2 March 2013 and 1 February 2018 was performed using clearly defined inclusion and exclusion criteria. 841 articles were found and 767 were excluded after screening the title and abstract. After fulltext analysis another 60 articles were excluded which left 14 articles to be included for data extraction. Fit was the mean of distances reported in the studies and accuracy was the fit minus the pre-set spacer Results: For marginal gap of single crowns and multi-unit FDPs combined, the fit was 83 lm and the accuracy was 59 lm. The internal gap fit was 111 lm and the accuracy 61 lm. For the total gap, the fit was 101 lm, and the accuracy of the zirconia restorations was 53 lm. Conclusions: Within the limitations of the present systematic review the fit of zirconia single crowns and multi-unit FDPs may be regarded as clinically acceptable, and the accuracy of the manufacturing of zirconia is $60 lm for marginal, internal, and total gap. Also, digital impressions seem to be associated with a smaller gap value.

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Trueness of four different milling procedures used in dental CAD/CAM systems

Cited by 85 publications

References 29 publications

Comparative Study of the Trueness of the Inner Surface of Crowns Fabricated from Three Types of Lithium Disilicate Blocks

Comparative Study of the Trueness of the Inner Surface of Crowns Fabricated from Three Types of Lithium Disilicate Blocks

Marginal and Internal Fit of CAD/CAM Crowns Fabricated Over Reverse Tapered Preparations

A systematic review on the accuracy of zirconia crowns and fixed dental prostheses

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