Bond Strength of Orthodontic Brackets to Temporary Crowns: In vitro Effects of Surface Treatment

ABSTRACT

Background:

To evaluate bond strength of orthodontic brackets to temporary crowns.

Materials and Methods:

A bis-acrylic composite was used to create a total of 25 discs, which were then divided into five groups based on how their surfaces were treated with black, blue, green, and sandblasted diamond burs, in addition to a control group. Software called SPSS was used to analyze the outcome.

Results:

The average pressures measured for the green bur, black bur, and sandblasting, respectively, were 12.05 MPa, 12.87 MPa, and 19.25 MPa. Comparing the control and blue groups, a substantial variation in shear bond strength was only noticed with reference to sandblasting.

Conclusion:

The binding strength of orthodontic brackets is increased by sandblasting temporary crowns.

INTRODUCTION

Adults are increasingly looking for orthodontic treatments, not just for aesthetic reasons but also because they are typically an intermediate step in dental rehabilitation.[1] Because that adult dentition is typically characterized by restorative procedures, orthodontists dealing with this new situation frequently need to bind brackets to restorations and temporary crowns.[2] The allegation that glueing brackets to restorations is more challenging than bonding them to natural teeth is a concern with this treatment. Although there has not been much research on temporary restorations, some of them have shown that they do not contain the minimum amount of bonding required to allow for tooth movement during orthodontic treatment.[2,3] A common practice for straightening teeth with fixed equipment is to glue orthodontic brackets to teeth.[4] Several individuals pursue orthodontic treatment for a variety of motives, which has led to numerous clinical difficulties throughout orthodontic therapy.[5-7]

To acquire bonded orthodontic brackets, prefabricated teeth (PfT) might be configured as temporary crowns or pontics. Shear bond strength (SBS) should, nevertheless, endure masticatory strain and orthodontic stresses.[8] Bond failures are not only irritating for patients, but they also lengthen chair time and raise expenditures, jeopardizing the effectiveness and efficiency of orthodontic treatment.[4,9] For making provisional crowns, a variety of materials are on the market, including polymethyl methacrylate (PMMA) resin and bis-acryl composite resin. The PCM that is most highly advised is bis-acryl composite resin because it outperformed PMMA in terms of marginal adaption, strength, color stability, and low exothermic reaction during setting.[8,10]

MATERIALS AND METHODS

A bis-acrylic composite was used to create a total of 25 discs, which were then divided into five groups based on how their surfaces were treated with black, blue, green, and sandblasted diamond burs, in addition to a control group. The discs had been attached with orthodontic brackets. Information was gathered. Thermocycling was applied to all specimens. It was tested to see how strong the shear bond was. The adhesive remnant index had been utilized to examine and categorize the quantity of composite resin that was still present on the specimen surfaces. The software called SPSS was used to analyze the outcome.

RESULTS

When compared to the mean shear bond strength measured in the blue bur that was 6.85 MPa, the mean for the control group had been 9.10 MPa that was significantly greater but not statistically noteworthy as shown in Table 1. It fell short of the average, which was 12.05 MPa, 12.87 MPa, and 19.25 MPa for the green bur, black bur, and sandblasting, respectively. Comparing the control and blue groups, a substantial change in shear bond strength was only viewed with reference to sandblasting.

Table 1.

Mean comparison of shear bond strength (MPa) among the groups

Comparison	Groups
	Control (n=5)	Blue	Green	Black	Sandblasting
Mean	9.10	6.85	12.05	12.87	19.25
Vs/control	-	P=0.9	P=0.95	P=0.86	0.001*
Vs/blue	-	-	0.5	0.2	0.001*
Vs/green	-	-	-	0.9	0.1
Vs/black	-	-	-	-	0.3

DISCUSSION

The definitive restorations are typically implanted following the orthodontic movement in comprehensive orthodontic treatments involving prosthetic rehabilitation; thus, the orthodontists must bind brackets on temporary crowns.[4,5,8-10] To give acceptable aesthetics during orthodontic treatment, the brackets are also glued to aesthetic pontic materials in the maintenance of dental space caused to extractions, traumatic loss, or missing teeth.[9] Therefore, in order to assess the bond strength of orthodontic brackets to temporary crowns, the current research was carried out.

In the current investigation, the average shear bond strength measured in the control group had been recorded at 9.10 MPa, which was significantly greater than the mean measured in the blue bur at 6.85 MPa but not statistically significant.

In research by Shahin SY et al., it was discovered that under thermal aging conditions, the shear bond strength of specimens treated with sandblasting was considerably greater than that of the control group as well as that of blue burs, but that there were no considerable variations among the two groups for different grit diamond burs. Thermocycling strengthens the binding strength of orthodontic brackets by sandblasting temporary crowns.[11]

Nevertheless, it was lower in the current investigation than mean values for the green bur, black bur, and sandblasting, which were 12.05 MPa, 12.87 MPa, and 19.25 MPa, respectively. Comparing the control and blue groups, a considerable variation in shear bond strength was only viewed with reference to sandblasting. SBS values in a different investigation by Garces GA et al. ranged from 1.5 to 14.9 MPa. Comparable values to those of the CAD/CAM material were shown by the sandblasted bis-acryl and sandblasted auto-curing PMMA groups, with values of 1 and 2 for bis-acryl and 2 for acrylic, respectively. In general, acrylic and CAD/CAM materials showed SBS values below the optimum strength for bonding brackets, whereas bis-acryl material displayed the greatest SBS values overall.[12]

The highest average was found by Haber D et al. when bonding to natural crowns, followed by the averages of groups 5 and 6. Group 1 had the lowest average, though. The averages for groups 2 and 4, as well as groups 5 and 6, were relatively similar. All groups’ averages showed a numerically noticeable variation, with the exception of groups 2 and 4 on the one hand and groups 5 and 6 on the other. A bond strength that is comparable to a natural crown was achieved by using a diamond bur in addition to the plastic conditioner and sandblasting in addition to that same product.[13] The type of surface treatment method used on the material for the temporary crown had a significant impact on the shear bond strength values in our specimen.[14-16] Because they had previously been employed in clinical settings for surface roughening, diamond burs and sandblasting were chosen. Diamond burs are frequently used by orthodontists to prepare the surface of temporary crowns prior to bracket bonding. As part of their investigation into the impacts of various surface pre-treatments, Dias FMCS et al.[16] found that diamond bur treatment increased the shear bond strength compared to the control group. According to surface treatment results from scanning electron microscopy, the increase in shear bond strength values with diamond bur roughening compared to the control group may be explained by the fact that mechanical abrasive methods that boost mechanical interlocking are likely the most important factor contributing to bond strength.[2,14,17]

CONCLUSION

The binding strength of orthodontic brackets is increased by sandblasting temporary crowns.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.