ORIGINAL ARTICLE

Year : 2015  |  Volume : 3  |  Issue : 2  |  Page : 101-107

Does self-etching primer safely bond bleached teeth? An in-vitro study

Arjun Karra¹, Mohammadi Begum Khan^2
1 Departments of Orthodontics and Dentofacial Orthopedics, Army College of Dental Sciences, Secunderabad, India
² Drs. Sudha and Nageswara Rao Pinnamineni Siddhartha Institute of Dental Sciences, Gunnavaram, Vijayawada, Andhra Pradesh, India

Correspondence Address:
Mohammadi Begum Khan
Room No.109, Post Graduate Students Girls Hostel, Drs. Sudha and Nageswara Rao Pinnamineni Siddhartha Institute of Dental Sciences Campus, Gunnavaram, Vijayawada - 521 286, Andhara Pradesh
India

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/2321-3825.149047

Aim: The purpose of this in-vitro study was to compare the effect of carbamide peroxide, 16% clinex-gel bleaching on shear bond strength using conventional bonding and self-etching primer bonding (SEP) and to find out how far the changes affect the shear bond strengths at clinically significant level on extracted human tooth enamel. Materials and Methods: Eighty freshly extracted human premolar teeth having moderate to severe dental fluorosis as per Dean's criteria were collected and divided into four groups of 20 each. The four groups are: Group I: Acid etching followed by bonding with Transbond XT (white), Group II: Bleaching, acid etching followed by bonding with Transbond XT (pink), Group III: SEP followed by bonding with Transbond XT (white). Group IV. Bleaching, acid-etching, followed by bonding with Transbond XT (pink). Results: There was a statistically significant difference between the four groups on comparing the mean shear bond strength of Group I, II, III, and IV by one-way analysis of variance test. Summary and Conclusion: Bleaching and bonding with SEP after 30 days storage have comparably similar shear bond strength to the unbleached acid etching group.

Keywords: Adhesive remnant index, artificial saliva, carbamide peroxide bleaching, human premolar teeth, instron machine, shear bond strength

Introduction

• To evaluate the shear bond strength with conventional bonding in nonbleached and bleached teeth.
• To evaluate the shear bond strength with SEP in nonbleached and bleached teeth.
• Comparison of shear bond strength of self-etching with conventional etching in nonbleached and bleached teeth.

Materials and Methods

Figure 1a,b: Sample of 80 specimens mounted in aluminium blocks Click here to view

• 0.4 g Nacl
• 1.21 g Kcl
• 0.78 g Na H ₂ PO4.2H ₂ 0
• 0.005 g Na ₂ S.9H ₂ 0
• 1 g urea

Figure 2: Instron testing machine Click here to view

Figure 3: Group I, II, III, IV at ×50 SEM Click here to view

Figure 4: Group 1, II, III, IV SEM at ×100 Click here to view

Figure 5: Group I, II, III, IV SEM at ×500 Click here to view

Figure 6: Group I, II, III, IV SEM at ×1000 Click here to view

a ² and S b ² estimated for two group N _a and N _b subjects, respectively, using F-test.

2. The proportion was compared using the Chi-square test of significance.

Where O = Observed value and E = Expected value

i = row and j = column

n₁ and n₂ = column total, n₁ , n₂ , n₃ = row total and

n = Grand total,

DF = degree freedom = (row−1) × (column−1)

P < 0.05 was taken to be statistically significant. Statistical Package for Social Science (SPSS, V 16, Transbond XT) was used.

Results

The specimens Groups II and IV were stored in artificial saliva for 30 days at room temperature and then tested for shear bond strength on Instron Universal Testing Machine. The force was recorded in Newton and converted into Mega Pascal. The mean shear bond strength for specimens in Group I was 13.02 ± 1.01 MPa. The corresponding values for Group II, Group III, and Group IV specimens were 11.04 ± 0.97 MPa, 12.89 ± 0.91 MPa, and 10.70 ± 0.68 MPa, respectively [Table 1]. The difference in the mean shear bond strength in different groups was tested with one-way ANOVA. The results revealed statistically significant difference in the mean shear bond strengths between the four groups [Table 2] and Graph 1]. The pair-wise comparison using Post-hoc Tukey HSD test revealed a statistically significant difference between Group I and Group II, Group II and Group III, Group I and Group IV, but no difference between Group I and Group III, Group II and Group IV indicating near to normal shear bond strength following the enamel preparations with a combination bleaching and acid etching, bleaching, and self-etching. This clearly indicated that the adhesive system employed for bonding the brackets did not have any influence on the shear bond strength.

Table 1: Distribution of mean shear bond strength in four different groups Click here to view

Table 2: Comparison of mean shear bond strengths in four groups Click here to view

After the failure of brackets, the ARI score for each sample in all the three groups was noted. The distribution of ARI scores between the four groups was tested using the Chi-square test. The study found a statistically significant difference in the distribution of ARI scores between the four groups [Table 3] and Graph 2]. In Group I, 15% of the samples had an ARI score between 3 and 4 (adhesive mode of bond failure) and 85% of the samples had an ARI scores between 1 and 2 (adhesive-cohesive mode of bond failure). In Group II, 95% of the samples had an ARI score between 4 and 5 (adhesive-cohesive mode of bond failure) and 5% of the samples had an ARI score of 3 (cohesive mode of bond failure). In Group III, 85% of the samples had an ARI score between 1a 2 and 3 (adhesive-cohesive mode of bond failure) and the remaining 15% of the samples had an ARI score between 4 and 5 (cohesive mode of bond failure). None of the samples in Group I had an ARI score of 5 (cohesive mode of bond failure) and none of the samples in Group II and Group IV had an ARI score of 1 (adhesive mode of bond failure). This indicates that the bond failure in Group II and Group IV specimens was adhesive-cohesive or cohesive mode, whereas in Group I, it was adhesive-cohesive or adhesive mode.

Table 3: Distribution of ARI scores of four groups Click here to view

In the present study, there were no statistically significant differences in Group II and Group IV. Group IV showed significantly lower shear bond strength values than the others. The results of the ARI score comparisons [Table 4] in the current study indicated that there were significant differences among the four groups tested. In Groups I and II, there was a higher frequency of ARI scores, indicating cohesive failures within the resin.

Table 4: Distribution of ARI score among the study groups Click here to view

Discussion

There is concern that vital bleaching could alter the surface topography of enamel and thus affect the bond strength of adhesives to enamel. Carbamide peroxide gel provides 25-35% hydrogen peroxide equivalent and its effect on human enamel composition and topography has been studied by Covington et al. ^[14] Their results suggested a controlled oxidation process in which the organic phase of the enamel is mobilized without producing grossly unacceptable enamel surface topography. Allison et al. ^[15] showed an alteration in the topography of acid-etched enamel of carbamide peroxide bleached teeth with the loss of regular prism boundaries when compared with the control. Scherer et al. ^[16] demonstrated that the use of a brush-on carbamide peroxide gel system for up to 30 days was found to have no effect on surface structure under SEM alterations in bond strength might be significant with regard to clinical operative procedures that involve composite resin bonding, such as bonding orthodontic brackets, porcelain veneers, composite veneers, or future composite restorations. ^[17] It has been proposed that residual oxygen from the bleaching agent inhibits resin polymerization. ^[18] Uysal et al. ^[5] stored their samples in artificial saliva for 30 days and suggested that a bonding delay of a minimum 2-3 weeks might be beneficial.

The following conclusions were made from this study:

1. On comparing the mean shear bond strength of Group I, Group II, Group III, and Group IV by one-way ANOVA test, there was no statistically significant difference between the groups (P = 0.000).
2. The highest mean shear bond strength on debonding was found in Group I, followed by Group III. Group IV had the lowest mean shear bond strength on debonding.
3. The pair-wise comparison between the three groups revealed a statistically significant difference in the mean shear bond strength between Group I and Group II (P = 0.000), Group I and Group III (P = 0.000). There was no statistically significant difference in the mean shear bond strength between Group II and Group IV (P = 0.954).
4. There was statistically significant difference in the ARI (Chi-square test) between the three groups (P < 0.05).
5. In Group I, 85% of the samples had cohesive mode of bond failure, and 15% of the samples had an adhesive-cohesive mode of bond failure.
6. In Group II, 95% of the samples had an adhesive-cohesive mode of bond failure, and 5% of the samples had a cohesive mode of bond failure.
7. In Group III, 60% of the samples had a cohesive mode of bond failure, and the remaining 40% of the samples had an adhesive-cohesive mode of bond failure.
8. In Group IV, 75% of the samples had an adhesive-cohesive mode of bond failure, and the remaining 25% of the samples had a cohesive mode of bond failure.

Summary and Conclusion

It is been mentioned in the literature that many states in India are considered to be endemic fluoride belts. Nalgonda district of Andhra Pradesh is an endemic fluoride belt where the concentration of fluoride in the drinking water ranges from 1.5 to 5 ppm. ^[19] Though not documented in the available dental literature, the Orthodontists in this area are facing the problem in achieving optimal bond strength and durable bonding. Frequent bracket failure at the compromised enamel interface remains a notable clinical challenge in bonding brackets to fluorosed enamel. The present study was an attempt to check the effect of bleaching and bonding on fluorosed enamel surface with a conclusion that bonding on bleached enamel is safe with SEP.

 

References

1.	Buonocore MG. A simple method of increasing the adhesion of acrylic filling materials to enamel surfaces. J Dent Res 1955;34:849-53.
2.	Newman GV. A post treatment survey of direct bonding of metal brackets. Am J Orthod Dentofacial Orthop 1976;74:197-9.
3.	Bishara SE, Sulieman AH, Olson M. Effect of enamel bleaching on the bonding strength of orthodontic brackets. Am J Orthod Dentofacial Orthop 1993;104:444-7.
4.	Uysal T, Basciftci FA, Usümez S, Sari Z, Buyukerkmen A. Can previously bleached teeth be bonded safely? Am J Orthod Dentofacial Orthop 2003;123:628-32.
5.	Uysal T, Ertas H, Sagsen B, Bulut H, Er O, Ustdal A. Can intra-coronally bleached teeth be bonded safely after antioxidant treatment? Dent Mater J 2010;29:47-52.
6.	Miles PG, Pontier JP, Bahiraei D, Close J The effect of carbamide peroxide bleach on the tensile bond strength of ceramic brackets: An in vitro study. Am J Orthod Dentofacial Orthop 1994;106:371-5.
7.	Bulut H, Turkun M, Kaya AD. Effect of an antioxidizing agent on the shear bond strength of brackets bonded to bleached human enamel. Am J Orthod Dentofacial Orthop 2006;129:266-72.
8.	Gungor AY, Turkkahraman H, Adanir N, Alkis H. Effects of fluorosis and self etching primers on shear bond strengths of orthodontic brackets. Eur J Dent 2009;3:173-7.
9.	Uysal T, Sisman A. Can previously bleached teeth be bonded safely using self-etching primer systems? Angle Orthod 2008;78:711-5.
10.	Nour El-din AK, Miller BH, Griggs JA, Wakefield C. Immediate bonding to bleached enamel. Oper Dent 2006;31:106-14.
11.	Titley KC, Torneck CD, Ruse ND. The effect of carbamide peroxide gel on the shear bond strength of microfilm resin to bovine enamel. J Dent Res 1992;71:20.
12.	Basting RT, Rodrigues JA, Serra MC, Pimenta LA. Shear bond strength of enamel treated with seven carbamide peroxide bleaching agents. J Esthet Restor Dent 2004;16:250-9.
13.	Tella S. Evaluation of antimicrobial potential of commonly used denture cleansing methods and denture cleansers. An in vitro study. MAHER Deemed University; 2007.
14.	Covington JS, Friend GW, Lamoreaux WJ, Perry T. Carbamide peroxide tooth bleaching effects on the enamel composition and topography. J Dent Res 1990;175:530.
15.	Allison R, Symons AL, Meyers IA. The effect of a vital bleaching technique on the surface integrity of enamel. Aust Dent J 1991;36:312.
16.	Scherer W, Cooper H, Ziegler B, Vijayaraghavan TV. At-home bleaching system: effects on enamel and cementum. J Esthet Dent 1991;3:54-6.
17.	Miyazaki M, Sato H, Sato T, Moore BK, Platt JA. Effect of a whitening agent application on enamel bond strength of self-etching primer systems. Am J Dent 2004;17:151-5.
18.	Josey AL, Meyers IA, Romaniuk K, Symons AL. The effect of a vital bleaching technique on enamel surface morphology and the bonding of composite resin to enamel. J Oral Rehabil 1996;23:244-50.
19.	Wang WN, Tarng TH. Evaluation of the sealant in orthodontic bonding. Am J Orthod Dentofacial Orthop 1991;100:209-11.

Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 

Tables

  [Table 1], [Table 2], [Table 3], [Table 4]