Title Use of self-etch primer in orthodontic patients with fixed full-arch appliances reduces bonding time but shows a tendency for higher risk of bonding failure compared to the conventional acid-etch technique.
Clinical Question In patients with full-arch fixed and bonded orthodontic appliances how does the use of self-etch primer alter the risk of attachment failure and bonding time compared to conventional acid etch technique?
Clinical Bottom Line In orthodontic patients with full-arch fixed and bonded appliances, the use of self-etch primer significantly reduces bonding time but shows a tendency for higher risk of bonding failure compared to the conventional acid-etch technique.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
22748994Fleming/2012A total of 3444 brackets from 212 patients with full-arch fixed and bonded orthodontic appliances from 5 randomized controlled or controlled clinical trials (RCT and CCT) were included in the review. 1721 brackets were bonded with acid-etch technique and 1723 were bonded using self-etch primer.Systematic review and meta-analysis
Key resultsCompared to patients treated with conventional acid-etch technique, the patients in the self-etch primer group showed a tendency for a higher risk of bond failure with odds ratio 1.35 and 95% Confidence Interval of 0.99-1.83 (P =0.06). However, bonding time with self etch primer was significantly reduced with a mean difference of 23.2 seconds per bracket and 95% Confidence Interval of 20.7-25.8 (P<0.001). This would result in saving 8 minutes per full bonding.
Evidence Search (self-etch[All Fields] AND ("dna primers"[MeSH Terms] OR ("dna"[All Fields] AND "primers"[All Fields]) OR "dna primers"[All Fields] OR "primer"[All Fields]) AND ("orthodontics"[MeSH Terms] OR "orthodontics"[All Fields]))
Comments on
The Evidence
The systematic review and meta-analysis of RTCs and CCTs present the highest level of evidence. After a comprehensive, detailed search for relevant trials, this review analyses 5 trials and includes in the meta-analysis a large sample size of 3444 brackets (1721 bonded with acid-etch technique and 1723 with self-etch primer) from 212 patients. This study shows evidence that the use of self-etch primer significantly reduces bonding time. However, even though there is a tendency for higher bond failure with the self-etch primer, this is not statistically significant since p=0.06. More RTCs are needed to determine the statistical significance of bond failure.
Applicability The findings of this study regarding bonding time are not only statistically significant but also clinically significant. The self-etch bonding technique is likely to result in modest time saving (8 min per full bonding) compared with the acid-etch technique. However, more studies are needed to determine the significant of bonding failure. Furthermore, the clinical significant of these failures can vary based on the operator technique.     
Specialty (General Dentistry) (Orthodontics) (Pediatric Dentistry)
Keywords Self-etch primer, bonding time, bond failure
ID# 2326
Date of submission 08/06/2012
E-mail lamani@uthscsa.edu
Author Ejvis Lamani
Co-author(s)
Co-author(s) e-mail
Faculty mentor Peter T. Gakunga, BDS, MS, PhD
Faculty mentor e-mail GAKUNGA@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?)
by Ejvis Lamani (San Antonio, TX) on 09/20/2012
Conventional acid-etch technique uses phosphoric acid solution for etching. Etching allows for mechanical interlocking by dissolution of some of the calcium from enamel. Prolonged etching is detrimental to enamel, hence rinsing is required prior to primer application. The primer coats and prepares enamel for bonding1. The self-etch system combines etching and priming and utilizes methacrylated phosphoric acid ester as its active agent. The acid is neutralized by reacting with the demineralized calcium and during the airburst, which slows down the penetration of enamel by the acid group. Primer molecules penetrate the enamel rods to the same depth as the acid groups. As the primer polymerizes, the acid group is incorporated into the network and inhibits any further acid penetration. The self-etch primer system allows for mechanical and chemical bonding 1. (PMID: 7726460)
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Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs)
None available