Effects of fluorosis on the shear bond strength of orthodontic brackets bonded with a self-etching primer

Pretreatments to bonding on enamel and dentin disorders: a systematic review

INTRODUCTION

This systematic review focuses on structural anomalies of enamel and dentin such as fluorosis (F), molar-incisor hypomineralization (MIH), amelogenesis imperfecta (AI), dentinogenesis imperfecta (DI), osteogenesis imperfecta (OI), and X-linked hypophosphatemia (XLH). These pathologies affect up to 31% of the population, posing challenges in the adhesion of direct restorations. The primary objective of this analysis is to examine the survival rate and/or bonding resistance of direct restorations on tissues affected by enamel and dentin disorders in humans. We aim to provide precise clinical recommendations for dentists to choose the appropriate bonding pretreatment for various enamel and dentin disorders.

METHODS

We systematically searched the medical literature to identify abstracts of interest indexed between 1993 and May 2024, from 4 databases (PubMed, PMC-PubMed, Web of Science and Cochrane Library). The results are reported following the PRISMA statement. The GRADE approach was used to assess the risk of bias.

RESULTS

The two authors included 27 studies out of the 600 identified. The data extracted from these studies are highly heterogeneous, and the mentioned bonding protocols are all different. 15 articles pertain to F, 7 to MIH, 5 to AI, and none focus on HSPM, dentin disorders and XLH. We identified 12 pretreatments of enamel or dentin (7 for F, 2 for MIH, and 3 for AI), including 3 strong recommendations. Additional studies are necessary to confirm the effectiveness of certain pretreatments. In developmental enamel defects, the main recommendation we collected is to bond on enamel with an etch-and-rinse technique on F and MIH. Considerations with lower strength of evidence include a deproteinization step on enamel on F, MIH and AI and modifications of the etching parameters on F and AI. The research strategy was registered on the Prospero platform (CRD42023447502).

Bonding to Fluorosed Teeth: A Review of the Literature

Excessive fluoride availability during tooth formation can cause structural alterations in enamel and dentin. These alterations may negatively impact the adhesion of various dental materials to teeth with dental fluorosis. The aim of this review of literature is to identify updates in bonding to fluorosed teeth and summarize relevant recommendations. Findings from the available literature suggest that bonding procedures may be carried out reliably on most fluorosed teeth with consideration to the severity of fluorosis and the employment of additional bond-enhancing measures for the severely involved teeth.

Effects of fluorosed enamel on orthodontic bracket bonding : An in vitro study

OBJECTIVE

To investigate the effect of enamel deproteinization and air abrasion on shear bond strength (SBS), adhesive remnant index (ARI) scores, and surface topography when bonding orthodontic brackets to fluorosed enamel.

MATERIALS AND METHODS

The sample included 90 fluorosed and 30 normal premolars divided into four groups: group I (fluorosed premolars subjected to air abrasion before acid etching), group II (fluorosed premolars subjected to deproteinization before acid etching), group III (fluorosed premolars; control for groups I and II), and group IV (normal premolars; control for group III). Bonding procedures included etching with 37% phosphoric acid, priming with TransbondTM XT primer (3M Unitek, Monrovia, CA, USA), and application of TransbondTM XT adhesive paste (composite; 3M Unitek, Monrovia, CA, USA). Air abrasion was done using 50 µm aluminum oxide particles under 0.28 MPa pressure for 5 s with the micro-etcher held at a distance of 10 mm. Deproteinization was done for 60 s with 5% sodium hypochlorite (NaOCl).

RESULTS

Fluorosed premolars subjected to deproteinization showed the lowest (median = 6.57 MPa) SBS among the four groups, followed by 8.14, 8.90, 8.14 MPa for groups I, III, and IV respectively. ARI scores were significantly different between the four groups (p = 0.006). Fluorosed enamel etched after air abrasion or deproteinization with NaOCl showed a predominance of type 4 etching pattern with some areas appearing unetched.

CONCLUSIONS

Shear bond strength of all groups was within the 6-8 MPa acceptable range for orthodontic purposes. Fluorosed premolars subjected to deproteinization showed the lowest values. Further studies are recommended to scrutinize the deproteinization technique.

Effect of erbium family laser etching on shear bond strength of enamel surfaces: A meta-analysis-PRISMA

BACKGROUND

Recently, laser etching has appealed to people's attention. It is meaningful to compare the effect of erbium-doped yttrium-aluminum-garnet (Er:YAG) and erbium-chromium; yttrium-scandium-gallium-garnet (Er,Cr:YSSG) laser etching parameters with acid etching on bond strength of enamel surfaces. As far as we know, there still remains no related meta-analysis. To evaluate the efficacy of Er:YAG and Er,Cr:YSSG lasers etching on shear bond strength (SBS) of brackets bonded to enamel. The meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, conducted with literature search.

METHODS

Twelve relevant randomized controlled trials (RCTs) were included.

RESULTS

The pooled analysis of SBS showed that there were no significant differences between erbium family lasers and acid etching. In the mass, we noticed they did not achieve statistical significance in the lasers etching and acid etching. However, pooled analysis of 5 studies showed the SBS bonding to enamel was lower in Er,Cr:YAG laser group compared with acid group. As a whole, there were statistical significance between erbium lasers groups and acid etching group in adhesive remnant index (ARI) aspects, which less adhesives remained can reduce damage to enamel. With regard to the rate of teeth with ARI score ≤2, the results in Er:YAG laser etching group were obviously higher than acid etching group.

CONCLUSION

Our data indicated that erbium lasers may be considered bonding of brackets to enamel instead of acid etching bonding to enamel.

Comparison of shear bond strength of orthodontic brackets bonded to human teeth with and without fluorotic enamel: a systematic review and meta-analysis of experimental in vitro studies

OBJECTIVE

The aim of this systematic review was to compare the shear bond strength (SBS) of orthodontic brackets bonded to human teeth with and without enamel fluorosis (EF) using conventional bonding interventions/techniques.

MATERIALS AND METHODS

An unrestricted search of indexed databases was performed with the following eligibility criteria: (a) human fluorotic teeth (experimental-group); (b) human teeth without fluorosis (control-group); (c) studies using phosphoric acid (PA) etching without air abrasion (AA), PA etching combined with AA, and application of self-etching primer (SEP) alone as bonding interventions/techniques; and (d) measuring SBS in megapascals (MPa). Data screening, selection, and extraction were performed by two reviewers. The risk of bias (rob) was assessed using the JBI Critical appraisal tool for Quasi-Experimental Studies. Meta-analyses were performed using a random effects model. The quality of available evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Ten in vitro studies were included. Subgroup analyses were performed for each intervention type. The SBS was significantly lower in fluorotic teeth when PA was used without AA (mean difference = 3.26 MPa, confidence interval: [1.00, 5.52]); and there were no significant differences for the PA combined with AA, and SEP interventions. All studies had a low rob. The overall level of evidence was at best low.

CONCLUSIONS

The SBS is lower in teeth with EF when traditional PA is used. No significant differences were found in SBS between teeth with and without EF when PA is used with AA or when SEP is used alone.

Deproteinization of Fluorosed Enamel with Sodium Hypochlorite Enhances the Shear Bond Strength of Orthodontic Brackets: An In vitro Study

Context:

Improving bonding strength to fluorosed teeh.

Aims:

To determine the effect of deproteinization using 5.25% sodium hypochlorite (NaOCl) prior to acid etching on shear bond strength of orthodontic brackets bonded to fluorosed teeth.

Settings and Design:

In vitro experimental study.

Methods and Material:

Forty freshly extracted human mandibular first premolars with TFI 4 were selected and divided into two groups of 20 each. In Group I the teeth were acid etched with 37% phosphoric acid and bonded with composite. In Group II the teeth were deproteinized with 5.25% NaOCl prior to acid etching with 37% phosphoric acid and were bonded with composite. Samples were then subjected to shear bond test by Instron Universal Testing machine. The sample from each group were selected for the SEM study (prior to bonding) to analyze the etching patterns achieved.

Statistical Analysis Used:

Data was checked for normality by Shapiro Wilk Test, to compare the two groups unpaired t test was used. P value was predetermined at ≤ 0.05.

Results:

The S BS of Group II (11.75 ± 2.83 MPa) was higher than Group I (7.44 ± 2.43 MPa) and the difference was statistically significant (P = 0.000). On SEM the etching pattern was more of type 1 and 2 in Group II.

Conclusions:

Deproteinization using 5.25% NaOCl prior to acid etching significantly increases the shear bond strength of brackets bonded to fluorosed teeth and can be used as a convenient and effective option in orthodontic bonding to fluorosed teeth.

Effects of adhesion promoter on orthodontic bonding in fluorosed teeth: A scanning electron microscopy study

Introduction:

The objectives of the present study were to elucidate the effects of fluorosis in orthodontic bonding and to evaluate the efficiency of an adhesion promoter (Assure Universal Bonding Resin) in bonding to fluorosed teeth.

Materials and Methods:

Extracted premolars were divided into two groups on the basis of Thylstrup and Fejerskov Index. Ten samples from each group were etched and evaluated for etching patterns using scanning electron microscope (SEM). The remaining samples were subdivided into four groups of 20 each on the basis of adhesives used: IA, IIA - Transbond XT and IB, IIB - Transbond XT plus Assure Universal Bonding Resin. Shear bond strength (SBS) was measured after 24 h using the universal testing machine. Adhesive remnant index (ARI) scores were recorded using SEM. Statistical analysis was conducted using a two-way analysis of variance, and Tukey's post hoc test was performed on SBS and ARI scores.

Results:

Similar etching patterns were observed in both fluorosed and nonfluorosed teeth. No significant differences were found in the SBS values observed in both groups (8.66 ± 3.19 vs. 8.53 ± 3.44, P = 1.000). Increase in SBS was observed when Assure Universal Bonding Resin was used. Higher ARI scores were observed when adhesion promoter was used for bonding.

Conclusions:

Mild-moderately fluorosed teeth etch in a manner similar to the nonfluorosed teeth. Similar bond strengths were achieved in fluorosed and nonfluorosed teeth when conventional composite was used. Use of adhesion promoter increases the bond strengths in both groups of teeth.

Factors Affecting the Shear Bond Strength of Orthodontic Brackets - a Review of In Vitro Studies

The adhesive material used to bond orthodontic brackets to teeth should neither fail during the treatment period, resulting in treatment delays, untoward expenses or patient inconvenience nor should it damage the enamel on debonding at the end of the treatment. Although the effectiveness of a bonding system and any unfavorable effects on the enamel may be studied by conducting in-vivo studies, it is nearly impossible to independently analyze different variables that influence a specific bonding system in the oral environment. In-vitro studies, on the other hand, may utilize more standardized protocols for testing different bonding systems and materials available. Thus, the present review focused attention on in-vitro studies and made an attempt to discuss material-related, teeth-related (fluorotic vs non-fluorotic teeth) and other miscellaneous factors that influences the shear bond strength of orthodontic brackets. Within the limitations of this review, using conventional acid-etch technique, ceramic brackets and bonding to non-fluorotic teeth was reported to have a positive influence on the shear bond strength of orthodontic brackets, but higher shear bond strength found on using ceramic brackets can be dangerous for the enamel.

Effects of long-term repeated topical fluoride applications and adhesion promoter on shear bond strengths of orthodontic brackets

Objective:

The purpose of this study was to assess the effects of long-term repeated topical application of fluoride before bonding and an adhesion promoter on the bond strength of orthodontic brackets.

Materials and Methods:

A total of 76 bovine incisors were collected and divided equally into four groups. In group 1, the brackets were bonded without topical fluoride application or adhesion promoter. In group 2, before bonding, the adhesion promoter was applied to nonfluoridated enamel. In group 3, the brackets were bonded without the application of the adhesion promoter to enamel, which had undergone long-term repeated topical fluoride treatments. Teeth in group 4 received the long-term repeated topical applications of fluoride, and the brackets were bonded using the adhesion promoter. All the brackets were bonded using BeautyOrtho Bond self-etching adhesive. The shear bond strength was measured and the bond failure modes were evaluated with the use of the adhesive remnant index (ARI) after debonding.

Results:

The mean shear bond strength was significantly lower in group 3 than in groups 1, 2, and 4, and there were no significant differences between the groups except for group 3. There were significant differences in the distribution of ARI scores between groups 2 and 3, and between groups 3 and 4.

Conclusions:

The adhesion promoter can recover the bond strength reduced by the long-term repeated topical applications of fluoride to the prefluoridation level and had a significantly great amount of adhesives left on either fluoridated or nonfluoridated enamel.