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Title Cement-Retained Implant Supported Metal Ceramic Crowns Are More Effective At Resisting Fracture Than Screw-Retained Implants
Clinical Question In a partially dentate patient desiring a metal ceramic implant restoration, how effective are cement-retained implant supported crowns at resisting fracture compared to screw-retained crowns?
Clinical Bottom Line For patients desiring metal ceramic implant restorations, cement-retained implants are superior in resisting ceramic crown fracture than screw-retained implants. This is supported by two clinical trials in which the cement-retained crowns outperformed screw-retained crowns by a statistically significant margin.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 15211294Terrado/200440 standardized maxillary premolar metal copings divided into 4 groupsIn-Vitro
Key resultsMean values of vertical load required to fracture crowns. Screw-retained metal ceramic crowns with screw-access in center of occlusal surface: 95.01+/-46.6 Kgf; Screw-retained metal ceramic crowns with screw-access 1 mm offset from center of occlusal surface: 108.61+/-57.9 Kgf; Cement-retained metal ceramic crowns 4 mm width BL: 390.94+/-151.3 Kgf; Cement-retained metal ceramic crowns 5 mm width BL: 380.04+/-211.8 Kgf.
#2) 22010095Nissan/201138 patients were treated with 221 implantsRCT
Key resultsThe ceramic fracture rate was higher in screw-retained (38% ± 0.3%) implant supported metal ceramic crowns compared to cement-retained (4% ± 0.1%) restorations (P < .001).
Evidence Search ("Dental Implants"[Mesh]) AND screw retained AND cement
Comments on
The Evidence
The first trial conducted by Terrado, et. al., was performed in-vitro. It consisted of four similar groups that differed only in the style of copings designed. The method of fabrication of the porcelain metal crown and their subsequent testing was identical in all four groups. Because the clinical trial was performed in-vitro, no follow up or test for compliance was necessary. Recall bias and competing interests appear non applicable in this case. The second trial performed by Nissan J, et. al., was a randomized controlled trial performed over the course of fifteen years. The clinical trial consisted of 38 patients receiving 221 implants. All patients began similarly; requiring implants. Patients were randomly assigned either cement-retained or screw-retained crowns, and follow-up exams were performed every 12 months. Although compliance levels were not provided, recall bias and competing interests are non applicable.
Applicability Because of the increased rate dental implants are being utilized, along with the different methods and strategies to place them, dentists should be aware of the success rates and longevity of the different types of implant restorations.
Specialty/Discipline (General Dentistry) (Oral Surgery) (Periodontics) (Prosthodontics)
Keywords Implant, Success, Fracture, Screw-Retained, Cement-Retained, Metal Ceramic
ID# 2262
Date of submission: 04/12/2012spacer
E-mail faraj@livemail.uthscsa.edu
Author Zade Faraj
Co-author(s) e-mail
Faculty mentor/Co-author Norma Olvera, DDS, MS
Faculty mentor/Co-author e-mail OlveraN@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
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Comments and Evidence-Based Updates on the CAT
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by Richard Wallach and Katherine Hoffman (San Antonio, TX) on 11/28/2017
A literature search conducted in November 2017 identified a randomized controlled trial, by Oermeier et al. in 2017 (PMID 28710653) to contradict the CAT original bottom line by showing no significant difference in rate of fracture, only in the pattern and type of fracture. However, this randomized controlled trial was performed in vitro, while one of the originally analyzed studies was performed in vivo, limiting the clinical applicability of the newer article

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