[Comparison of 1-stage orthodontic bonding systems and 2-stage bonding systems: a review of the literature and the results of a randomized clinical trial]

Comparison of self-etch primers with conventional acid-etch technique for bonding brackets in orthodontics: a systematic review and meta-analysis

BACKGROUND

Bonding with self-etch primers (SEPs) is one of the most popular systems for attaching orthodontic brackets to the enamel surface. There are conflicting reports about the efficacy and success of these systems compared with acid-etch (AE) bonding.

OBJECTIVE

This systematic review and meta-analysis was performed to compare SEP with conventional AE technique for bonding brackets in fixed orthodontics.

SEARCH METHODS

Articles related to the subject of interest were searched in electronic databases, including PubMed, ISI Web of Science, Scopus, EMBASE, and Cochrane's CENTRAL, from inception to 2 June 2021. Search for grey literature, and hand search for relevant studies were also performed.

SELECTION CRITERIA

Based on the PICO model, randomized clinical trials using full-arch bonded fixed orthodontic appliances comparing SEP and conventional AE systems were included in the review process.

DATA COLLECTION AND ANALYSIS

After assessing the risk of bias, data from the included studies were extracted using custom piloted forms. Inverse-variance random-effects meta-analyses were performed to combine the results of bracket failure, adhesive remnant index (ARI), and bonding time.

RESULTS

Nineteen randomized clinical trials were included in the systematic review and 17 randomized clinical trials [5 parallel-group (PG) and 12 split-mouth (SM) studies] were included in the meta-analysis. No significant difference in bracket failure at 6 months [risk ratio (RR) = 1.50, P = 0.26, 12 SM] and (RR = 0.68, P = 0.34, 2 PG), 12 months (RR = 1.6, 8 SM) and (RR = 1.17, P = 0.54, 2 PG), and ≥18 months (RR = 0.84, P = 0.31, 3 SM) and (RR = 1.20, P = 0.3, 3 PG) between SEP and AE groups could be found. Also, ARI score was similar between different bonding systems [mean difference (MD) = -0.44, P = 0.06, 4 SM]. The bonding time per tooth was faster in the SEP group (MD = -26.55, P < 0.001, 2 SM) and (MD = -24.00, P < 0.001, 2 PG).

LIMITATIONS

inclusion of three studies with a high risk of bias and high amount of inconsistency between the results of individual studies were the biggest limitations of our review.

CONCLUSIONS

The bracket bonding failure and ARI score were not significantly different between self-etch and conventional AE bonding systems. The bonding time was lower for the SEP, but some other requirements for SEPs like pumice prophylaxis could diminish this advantage.

REGISTRATION

The protocol for this systematic review was registered at PROSPERO with the ID CRD42021248540.

Shear bond strength and debonding characteristics of a new premixed self-etching with a reference total-etch adhesive

Background

To determine the shear bond strength and adhesive remnant index of a new premixed self-etching primer and adhesive (Tectosan, BonaDent, Germany) for orthodontic appliances in comparison to a reference total-etch system Transbond XT.

Methods

Bovine incisors were embedded in resin and randomly divided into two groups of 16 samples each. Brackets (Discovery, Dentaurum, Germany) were bonded in group 1 (total-etch-system, Transbond XT) and in group 2 (self-etch-system, Tectosan) with curing light for 40 s. Shear bonding strengths were measured after 24 h of storage in distilled water at 37 °C with a Zwicki 1120 testing machine (Zwick Roell, Germany). A force was applied on the bracket base at the wings in occluso-gingival direction. Then the adhesive remnant index (ARI) was determined.

Results

No statistical differences on SBS were found for both bonding agents (p = 0.63). ARI scores however differed statistically significantly (p = 0.035): in the total-etch group more adhesive remained on the teeth, whereas in the self-etch group more adhesive remained on the brackets. There were no visible enamel damages in both groups.

Conclusions

No differences in the shear bond strength were found between both bonding agents. In our study the self-etch-system shifted the adhesive remnant index from more adhesive on the teeth to more adhesive on the bracket - as other already published self-etch systems did - with the new benefit of not increased enamel damages. Tectosan might therefore be a promising alternative to adhesive systems.

Enamel etching for bonding fixed orthodontic braces

BACKGROUND

Acid etching of tooth surfaces to promote the bonding of orthodontic attachments to the enamel has been a routine procedure in orthodontic treatment since the 1960s. Various types of orthodontic etchants and etching techniques have been introduced in the past five decades. Although a large amount of information on this topic has been published, there is a significant lack of consensus regarding the clinical effects of different dental etchants and etching techniques.

OBJECTIVES

To compare the effects of different dental etchants and different etching techniques for the bonding of fixed orthodontic appliances.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 8 March 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 2), MEDLINE via OVID (to 8 March 2013), EMBASE via OVID (to 8 March 2013), Chinese Biomedical Literature Database (to 12 March 2011), the WHO International Clinical Trials Registry Platform (to 8 March 2013) and the National Institutes of Health Clinical Trials Registry (to 8 March 2013). A handsearching group updated the handsearching of journals, carried out as part of the Cochrane Worldwide Handsearching Programme, to the most current issue. There were no restrictions regarding language or date of publication.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing different etching materials, or different etching techniques using the same etchants, for the bonding of fixed orthodontic brackets to incisors, canines and premolars in children and adults.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and assessed the risk of bias of included studies independently and in duplicate. We resolved disagreements by discussion among the review team. We contacted the corresponding authors of the included studies to obtain additional information, if necessary.

MAIN RESULTS

We included 13 studies randomizing 417 participants with 7184 teeth/brackets. We assessed two studies (15%) as being at low risk of bias, 10 studies (77%) as being at high risk of bias and one study (8%) as being at unclear risk of bias. Self etching primers (SEPs) versus conventional etchantsEleven studies compared the effects of SEPs with conventional etchants. Only five of these studies (three of split-mouth design and two of parallel design) reported data at the participant level, with the remaining studies reporting at the tooth level, thus ignoring clustering/the paired nature of the data. A meta-analysis of these five studies, with follow-up ranging from 5 to 37 months, provided low-quality evidence that was insufficient to determine whether or not there is a difference in bond failure rate between SEPs and convention etchants (risk ratio 1.14; 95% confidence interval (CI) 0.75 to 1.73; 221 participants). The uncertainty in the CI includes both no effect and appreciable benefit and harm. Subgroup analysis did not show a difference between split-mouth and parallel studies.There were no data available to allow assessment of the outcomes: decalcification, participant satisfaction and cost-effectiveness. One study reported decalcification, but only at the tooth level. SEPs versus SEPsTwo studies compared two different SEPs. Both studies reported bond failure rate, with one of the studies also reporting decalcification. However, as both studies reported outcomes only at the tooth level, there were no data available to evaluate the superiority of any of the SEPs over the others investigated with regards to any of the outcomes of this review.We did not find any eligible studies evaluating different etching materials (e.g. phosphoric acid, polyacrylic acid, maleic acid), concentrations or etching times.

AUTHORS' CONCLUSIONS

We found low-quality evidence that was insufficient to conclude whether or not there is a difference in bond failure rate between SEPs and conventional etching systems when bonding fixed orthodontic appliances over a 5- to 37-month follow-up. Insufficient data were also available to allow any conclusions to be formed regarding the superiority of SEPs or conventional etching for the outcomes: decalcification, participant satisfaction and cost-effectiveness, or regarding the superiority of different etching materials, concentrations or etching times, or of any one SEP over another. Further well-designed RCTs on this topic are needed to provide more evidence in order to answer these clinical questions.