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

Effects of different primers and colouring solutions on orthodontic bonding: shear bond strength and colour change

OBJECTIVES

This in vitro study evaluated the effect of different colouring solutions and primer systems used in the bonding of brackets on enamel colour change and bond strength.

MATERIALS AND METHODS

120 premolar teeth were divided into four main groups; brackets were bonded with 37% orthophosphoric acid + Transbond XT Primer in Group 1, 3 M Single Bond Universal in Group 2, Transbond Plus SEP in Group 3, and G-Premio Bond in Group 4. Each group was divided into three subgroups, and the teeth were placed in a cup containing coffee and tea mixture, in a cup containing cola and in distilled water. A bond strength test was applied to all teeth. Colour measurements of all teeth were performed at 2 different times: before bonding and after the bond strength test.

RESULTS

The average bond strength of the 37% orthophosphoric acid group was higher than that of the other groups. The effect of primer and solution groups on colour change was statistically significant (p = 0.001 and p = 0.023, respectively).

CONCLUSIONS

In this study, the bond strength was clinically sufficient in all primer groups. The highest colour change was observed when the tea-coffee solution and Transbond Plus SEP primer were used.

CLINICAL RELEVANCE

This study has identified enamel discoloration and bond strength from different colouring solutions and primer systems used for bonding braces, which can be used to inform clinicians and patients to achieve better treatment results.

Clinical bracket failure rates between different bonding techniques: a systematic review and meta-analysis

BACKGROUND

Bracket failure increases the treatment time of orthodontic therapy and burdens patients with unnecessary costs, increased chair time, and possible new appointments.

OBJECTIVE

To compare the bond failures of different orthodontic materials based on the results of available clinical studies.

SEARCH METHODS

A systematic search of clinical trials was performed in the Cochrane, Embase, and Pubmed databases with no limitations. The list of investigated techniques contained conventional acid-etch primer (CM-AEP), self-etch primer (SEP), self-cure resin (SCR), and simple or resin-modified glass ionomer (RM-GIC) materials and procedures.

SELECTION CRITERIA

Clinical studies reporting the failure rate of bonded brackets after using direct adhesive techniques on buccal sites of healthy teeth were included.

DATA COLLECTION AND ANALYSIS

Bracket failure rates from eligible studies were extracted by two authors independently. Risk ratios (RRs) were pooled using the random-effects model with DerSimonian-Laird estimation.

RESULTS

Thirty-four publications, involving 1221 patients, were included. Our meta-analysis revealed no significant difference in the risk of bracket failures between SEP and CM-AEP. After 6, 12, and 18 months of bonding, the values of RR were 1.04 [95% confidence interval (CI), 0.67-1.61], 1.37 (95% CI, 0.98-1.92), and 0.93 (95% CI, 0.72-1.20), respectively. At 18 months, bracket failure was 4.9 and 5.2% for SEP and CM-AEP, respectively. Heterogeneity was good or moderate (I2 < 42.2%). The results of RM-GIC at 12 months indicated a 57% lower risk of bracket failure using SCR as compared with RM-GIC (RR: 0.38; 95% CI, 0.24-0.61). At 18 months, bracket failures for SCR and RM-GIC were 15.8 and 36.6%, respectively (RR: 0.44; 95% CI, 0.37-0.52, I2 = 78.9%), demonstrating three to six times higher failure rate than in the case of etching primer applications.

LIMITATIONS

A major limitation of the present work is that the included clinical trials, with no exceptions, showed variable levels of risk of bias. Another possible problem affecting the outcome is the difference between the clustering effects of the split mouth and the parallel group bracket allocation methods.

CONCLUSIONS AND IMPLICATIONS

The results revealed no significant difference between SEP and CM-AEP up to 18 months after application. RM-GIC had much worse failure rates than acid-etching methods; additionally, the superiority of SCR over RM-GIC was evident, indicating strong clinical relevance.

REGISTRATION

Prospero with CRD42020163362.