Fracture resistance of computer-aided design and computer-aided manufacturing ceramic crowns cemented on solid abutments.

Abstract

BACKGROUND:

Because no information was found in the dental literature regarding the fracture resistance of all-ceramic crowns using CEREC (Sirona) computer-aided design and computer-aided manufacturing (CAD-CAM) system on solid abutments, the authors conducted a study.

METHODS:

Sixty synOcta (Straumann) implant replicas and regular neck solid abutments were embedded in acrylic resin and randomly assigned (n = 20 per group). Three types of ceramics were used: feldspathic, CEREC VITABLOCS Mark II (VITA); leucite, IPS Empress CAD (Ivoclar Vivadent); and lithium disilicate, IPS e.max CAD (Ivoclar Vivadent). The crowns were fabricated by the CEREC CAD-CAM system. After receiving glaze, the crowns were cemented with RelyX U200 (3M ESPE) resin cement under load of 1 kilogram. For each ceramic, one-half of the specimens were subjected to the fracture resistance testing in a universal testing machine with a crosshead speed of 1 millimeter per minute, and the other half were subjected to the fractured resistance testing after 1,000,000 cyclic fatigue loading at 100 newtons.

RESULTS:

According to a 2-way analysis of variance, the interaction between the material and mechanical cycling was significant (P = .0001). According to a Tukey test (α = .05), the fracture resistance findings with or without cyclic fatigue loading were as follows, respectively: CEREC VITABLOCKS Mark II (405 N/454 N) was statistically lower than IPS Empress CAD (1169 N/1240 N) and IPS e.max CAD (1378 N/1025 N) (P < .05). The IPS Empress CAD and IPS e.max CAD did not differ statistically (P > .05). According to a t test, there was no statistical difference in the fracture resistance with and without cyclic fatigue loading for CEREC VITABLOCS Mark II and IPS Empress CAD (P > .05). For IPS e.max CAD, the fracture resistance without cyclic fatigue loading was statistically superior to that obtained with cyclic fatigue loading (P < .05).

CONCLUSIONS:

The IPS Empress CAD and IPS e.max CAD showed higher fracture resistance compared with CEREC VITABLOCS Mark II. The cyclic fatigue loading negatively influenced only IPS e.max CAD.

PRACTICAL IMPLICATIONS:

The CEREC VITABLOCS Mark II, IPS Empress CAD, and IPS e.max CAD ceramic crowns cemented on solid abutments showed sufficient resistance to withstand normal chewing forces.

• Authors: Deborah Stona, Luiz Henrique Burnett Jr, Eduardo Gonçalves Mota, Ana Maria Spohr
• Journal: Journal of the American Dental Association (1939) (J Am Dent Assoc) Vol. 146 Issue 7 Pg. 501-7 (Jul 2015) ISSN: 1943-4723 [Electronic] England
• PMID: 26113098 (Publication Type: Journal Article, Randomized Controlled Trial)
• Copyright: Copyright © 2015 American Dental Association. Published by Elsevier Inc. All rights reserved.

Topics

• Ceramics (therapeutic use)
• Computer-Aided Design
• Crowns
• Dental Abutments
• Dental Implant-Abutment Design (methods, standards)
• Dental Restoration Failure
• Dental Stress Analysis
• Humans