Five-year results of a prospective randomised controlled clinical trial of posterior computer-aided design-computer-aided manufacturing ZrSiO4
-ceramic crowns

Clinical Relevance Marginal misfit of monolithic lithium disilicate ceramic crowns obtained from a chairside computer-aided design/computer-aided manufacturing system is affected after successive millings using a single diamond bur set. This fact can be critical for the longevity of indirect restorations. SUMMARY Objectives: This laboratory study aimed to assess the effect of successive crown millings on the marginal misfit of monolithic full-ceramic restorations obtained from two lithium disilicate systems, with a single diamond bur set used for each material in a chairside computer-aided design/computer-aided manufacturing (CAD/CAM) unit. Methods and Materials: Initially, 36 standardized composite resin dies were produced by additive manufacturing from a three-dimensional model of a right mandibular first molar with full-crown preparation generated in CAD software. Individual ceramic crowns were obtained in a chairside CAD/CAM unit (CEREC MC XL) for each composite resin die according to the ceramic system (IPS e.max CAD and Rosetta SM; n=18). Two new diamond burs were used as a set for obtaining the crowns in each experimental group (ceramic systems), and the milling periods were defined after three crown millings (T0-T6), when the diamond bur set of each system was removed for morphologic characterization using scanning electron microscopy (SEM). The marginal misfit of the crowns was assessed through coronal and sagittal micro-tomographic sectioning, in the vertical and horizontal directions of the ceramic crowns seated on their respective resin dies. The collected data were tabulated and subjected to one-way analysis of variance and Tukey's honestly significant difference test (α=0.05). Results: SEM images showed changes in the superficial morphology of the diamond bur sets, with progressive loss of the diamond granules after the successive millings of crowns for both experimental groups. Significant differences were detected in the marginal misfit of the crowns from both ceramic systems at the different milling periods (p<0.001). Conclusions: Diamond burs deteriorated after successive crown millings for both lithium disilicate ceramic systems. The marginal misfit of the crowns obtained increased with the successive use of the CAD/CAM diamond bur set employed for milling each ceramic material. In addition, new milling of full lithium disilicate ceramic crowns can be inappropriate after 11 successive millings for IPS e.max CAD and 12 for Rosetta SM, due to the increased marginal misfit observed under the parameters tested.

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Fractography of clinically fractured, implant-supported dental computer-aided design and computer-aided manufacturing crowns

SAGE Open Medical Case Reports ◽

10.1177/2050313x17741015 ◽

2017 ◽

Vol 5 ◽

pp. 2050313X1774101 ◽

Cited By ~ 5

Author(s):

Ulrich Lohbauer ◽

Renan Belli ◽

Marco S Cune ◽

Ulf Schepke

Keyword(s):

Clinical Trial ◽

Water Absorption ◽

Computer Aided Design ◽

Interfacial Stress ◽

Computer Aided Manufacturing ◽

Implant Abutments ◽

Computer Aided ◽

Cad Cam ◽

Aided Design ◽

Zirconia Implant

Today, a substantial part of the dental crown production uses computer-aided design and computer-aided manufacturing (CAD/CAM) technology. A recent step in restorative dentistry is the replacement of natural tooth structure with pre-polymerized and machined resin-based methacrylic polymers. Recently, a new CAD/CAM composite was launched for the crown indication in the load-bearing area, but the clinical reality forced the manufacturer to withdraw this specific indication. In parallel, a randomized clinical trial of CAD/CAM composite crowns luted on zirconia implant abutments revealed a high incidence of failure within the first year of service. Fractured crowns of this clinical trial were retrieved and submitted to a fractographic examination. The aim of the case series presented in this article was to identify failure reasons for a new type of CAD/CAM composite crown material (Lava Ultimate; 3M Oral Care, St. Paul, Minnesota, USA) via fractographic examinations and analytical assessment of luting surfaces and water absorption behavior. As a result, the debonding of the composite crowns from the zirconia implant abutments was identified as the central reason for failure. The adhesive interface was found the weakest link. A lack of silica at the zirconia surface certainly has compromised the bonding potential of the adhesive system from the beginning. Additionally, the hydrolytic stress released from swelling of the resin-based crown (water absorption) and transfer to the luting interface further added to the interfacial stress and most probably contributed to a great extend to the debonding failure.

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Effect of resin coating on adhesion and microleakage of computer-aided design/computer-aided manufacturing fabricated all-ceramic crowns after occlusal loading: a laboratory study

European Journal Of Oral Sciences ◽

10.1111/j.1600-0722.2009.00653.x ◽

2009 ◽

Vol 117 (4) ◽

pp. 454-462 ◽

Cited By ~ 5

Author(s):

Shuzo Kitayama ◽

Peter Pilecki ◽

Nasser A. Nasser ◽

Theodora Bravis ◽

Ron F. Wilson ◽

...

Keyword(s):

Laboratory Study ◽

Computer Aided Design ◽

Computer Aided Manufacturing ◽

Resin Coating ◽

All Ceramic ◽

Computer Aided ◽

Ceramic Crowns ◽

Aided Design

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Internal fit of pressed and computer-aided design/computer-aided manufacturing ceramic crowns made from digital and conventional impressions

Journal of Prosthetic Dentistry ◽

10.1016/j.prosdent.2014.09.015 ◽

2015 ◽

Vol 113 (4) ◽

pp. 304-309 ◽

Cited By ~ 63

Author(s):

Evanthia Anadioti ◽

Steven A. Aquilino ◽

David G. Gratton ◽

Julie A. Holloway ◽

Isabelle L. Denry ◽

...

Keyword(s):

Computer Aided Design ◽

Computer Aided Manufacturing ◽

Computer Aided ◽

Ceramic Crowns ◽

Aided Design ◽

Internal Fit

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Dual-scan technique for the customization of zirconia computer-aided design/computer-aided manufacturing frameworks

European Journal of Dentistry ◽

10.4103/1305-7456.119088 ◽

2013 ◽

Vol 07 (S 01) ◽

pp. S115-S118 ◽

Cited By ~ 2

Author(s):

Rafael Ferrone Andreiuolo ◽

Carlos Eduardo Sabrosa ◽

Katia Regina H. Cervantes Dias

Keyword(s):

Computer Aided Design ◽

Uniform Thickness ◽

Simple Manner ◽

Computer Aided Manufacturing ◽

All Ceramic ◽

Computer Aided ◽

Cad Cam ◽

Ceramic Crowns ◽

Tooth Preparation ◽

Aided Design

ABSTRACTThe use of bi-layered all-ceramic crowns has continuously grown since the introduction of computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia cores. Unfortunately, despite the outstanding mechanical properties of zirconia, problems related to porcelain cracking or chipping remain. One of the reasons for this is that ceramic copings are usually milled to uniform thicknesses of 0.3-0.6 mm around the whole tooth preparation. This may not provide uniform thickness or appropriate support for the veneering porcelain. To prevent these problems, the dual-scan technique demonstrates an alternative that allows the restorative team to customize zirconia CAD/CAM frameworks with adequate porcelain thickness and support in a simple manner.

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