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Title Class IV, Bevel Or Chamfer?
Clinical Question In a healthy adult needing a class IV restoration, is a stair-step margin preparation or a beveled margin preparation more resistant to fracture?
Clinical Bottom Line There is no difference in shear strength between the bevel and stair step chamfer margin preparation in a class IV resin composite restoration. (See Comments on the CAT below)
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) 12739678Eid/2002Bovine TeethLab study
Key resultsANOVA showed a significant difference in the shear strengths in mega Pascals between the control group (Untreated samples) and the three different preparation techniques P level <0.001, and no significant difference among the different types of preparation P level > 0.05.
Evidence Search Limits: Humans, Randomized Controlled Trial Limits: Humans, Clinical Trial Limits: Humans, Systematic ReviewsLimits: Humans, Meta-AnalysisSearch "Tooth Fractures"[Mesh]Search "Incisor"[Mesh]Search "Composite Resins"[Mesh]Search ("Tooth Preparation"[Mesh]
Comments on
The Evidence
The study was not blinded and took place on bovine extracted teeth. The sample sizes were smaller than we would have liked.
Applicability The healthy adult patient would not receive a major benefit using one of these preparation designs over the other.
Specialty/Discipline (General Dentistry) (Pediatric Dentistry)
Keywords Class IV, chamfer
ID# 853
Date of submission: 04/01/2011spacer
E-mail desutterb@livemail.uthscsa.edu
Author Brent DeSutter
Co-author(s) e-mail
Faculty mentor/Co-author Erica Oliveira, DDS, MPH
Faculty mentor/Co-author e-mail OLIVEIRAE@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?)
post a rationale
None available
Comments on the CAT
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by Saba Ghazal (San Antonio, TX) on 10/03/2014
A PubMed search on fracture resistance of bevel and stair stepped chamfer Class IV composites was performed in September 2014. A more recent publication was found: Xu 2012, PubMed: 22409223. This in vitro study was conducted on sixty extracted bovine teeth and showed similar results as those published in this CAT and, in addition, indicated a stair stepped chamfer or 2mm bevel for better biomechanics and esthetics.

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