|Year : 2020 | Volume
| Issue : 5 | Page : 470-475
The comparison of shear bond strength of metal orthodontics bracket to porcelain surface using silane and single bond: An in vitro study
Chitra Martalia, Citra Anggitia, Thalca Hamid, Jusuf Sjamsudin
Department of Orthodontics, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia
|Date of Submission||13-Feb-2020|
|Date of Decision||09-Apr-2020|
|Date of Acceptance||19-Apr-2020|
|Date of Web Publication||21-Oct-2020|
Prof. Thalca Hamid
Department of Orthodontics, Faculty of Dental Medicine, Universitas Airlangga, Surabaya.
Source of Support: None, Conflict of Interest: None
Aim: To investigate the dissimilarity of the shear bond strength of bracket on porcelain surface using silane and single bond. Materials and Methods: This study was laboratory experimental research with posttest-only group design. Simple random sampling was performed to select the sample. Twenty-eight porcelain veneers were used as sample, then divided into four groups accordingly: hydrofluoric acid, silane, bonding, and adhesive (I); hydrofluoric acid, single bond, bonding, and adhesive (II); hydrofluoric acid, bonding, and adhesive (III); and single bond and adhesive (IV). Shear bond strength of brackets was performed by means of universal testing machine. Scanning electron microscope was used to examine the porcelain surface roughness. Wilcoxon Mann–Whitney test (P < 0.05) was performed to analyze the difference between groups. Result: The shear bond strengths between groups were significantly different (P < 0.05). The greatest bracket shear bond strength and lowest porcelain surface roughness were found in hydrofluoric acid, silane, bonding, and adhesive. Conclusion: Silane applied separately from bonding and acid has great shear bond strength and low porcelain surface roughness.
Keywords: Dental Porcelain, Orthodontic Bracket, Shear Strength, Silane, Single Bond
|How to cite this article:|
Martalia C, Anggitia C, Hamid T, Sjamsudin J. The comparison of shear bond strength of metal orthodontics bracket to porcelain surface using silane and single bond: An in vitro study. J Int Oral Health 2020;12:470-5
|How to cite this URL:|
Martalia C, Anggitia C, Hamid T, Sjamsudin J. The comparison of shear bond strength of metal orthodontics bracket to porcelain surface using silane and single bond: An in vitro study. J Int Oral Health [serial online] 2020 [cited 2020 Nov 27];12:470-5. Available from: https://www.jioh.org/text.asp?2020/12/5/470/298799
| Introduction|| |
Orthodontic treatment consists of fixed and removable appliances. Fixed orthodontic treatment uses a bracket to move orthodontic forces through archwire, ligature, and auxiliary., Orthodontic bracket detachment is one of the problems that orthodontists often encounter. The bracket detachment from the tooth surface will affect the orthodontic treatment process. The treatment process will take longer and as a result, it will prolong pain or discomfort experienced by patients. Bond failure may occur between adhesive and teeth or between adhesive and brackets. The presence of saliva contamination in bonding procedure may increase bond failure. Furthermore, bond failure may also occur when the force applied to the bracket is greater than bond strength. The bracket’s bond can at least withstand a pressure force of 6–8 megapascals (MPa).,,
Brackets are generally attached directly to the enamel surface of the teeth, but the brackets may also be placed on teeth with artificial dental crown and filled teeth. Special treatment is required to make porcelain surfaces rougher to increase bracket strength. To produce a good bond, a rougher porcelain surface obtained by using a process such as drilling, sand blasting, and etching is needed. This process is called a mechanical bonding. The process of drilling and etching that is not performed carefully can cause cracks and fractures on the porcelain crown, and this condition is very unfavorable for patients. In addition to mechanical bonding, there is another technique called chemical bonding by using silane. The chemical bonding mechanism is known to be able to retain porcelain surfaces after orthodontic treatment is completed.
The basic materials of porcelain are aluminum peroxide (Al2O3) which is a very hard oxide derived from trihydroxide, silicon dioxide (SiO2), and feldspar (K2O.Al2O3.6SiO2) consisting of minerals of anhydrous aluminum silicate.
The orthodontic treatment on the porcelain surface is carried out using special materials such as 9% hydrofluoric acid and silane. According to Eliades and Brantley, hydrofluoric acid used in porcelain greatly increases bond strength as acid has an ability to react with the silica phase to produce micromechanical retention on porcelain surface. Silanization is usually used for restoration repair such as repairing crown, bridge, inlay/onlay, veener made of porcelain, metal, or composite.
As technology evolves, there is a new material called seventh-generation bonding, namely Single Bond Universal. Single-bond universal or also called seventh-generation self-etch dentin bonding agent not only simplifies the bonding application but also saves bonding application time. Single bond is the development of a self-etch that combines etching, priming, and bonding in one bottle, otherwise known as one-step self-etch system. The silane content in single bond makes attachment to the ceramic glass surface possible without the need for separate primary materials., Our hypothesis was that silane application could increase the bond strength of orthodontic bracket. Thus, the purpose of this research was to investigate the dissimilarity of shear bond strength of metal bracket on porcelain surface using silane and single bond.
| Materials and Methods|| |
This research was laboratory experimental research with posttest-only group design. The subjects of their search were porcelain fused to metals that had been glazed with the same shape and size. This study was carried out in Research Center of Faculty of Dental Medicine, Airlangga University, Surabaya, Indonesia from August to October 2017 (3 months).
There were 28 samples divided into four groups, each of which consisted of seven samples. The number of samples needed was from minimum sample size formula. Simple random sampling was performed to select the sample in this study. Hydrofluoric acid 9% (Ultradent Product Inc, Jordan, UT, USA), Silane Ultradent (Ultradent), Ortho Solo bonding and Grengloo (ORMCO Corp., CA, USA) adhesive bracket, Single Bond Universal 3M ESPE, Bracket Edgewise metal (Ortho Organizer Inc, CA, USA). The composition of Silane Ultradent and Single Bond Universal can be seen in [Table 1].
The steps for porcelain treatment in Group I: First, we apply 9% hydrofluoric acid for 90s in the surface of porcelain, then the sample. In addition, aquades was used to rinse the sample for 5s, then dry it with air spray on the dental unit for 5s. After those steps, apply Silane, dry it with air spray on the dental unit for 60s, apply Ortho Solo, and apply Grenglo adhesive to bracket mess. Press bracket on porcelain surface using bracket holder, clean excess residue, and for the last step do light-curing for 20s.
The steps for porcelain treatment in Group II: First, apply 9% hydrofluoric acid for 90s, rinse with aquades for 5s, then dry with air spray on the dental unit for 5s. After those steps, apply Single Bond, light-curing for 10s and apply Grenglo adhesive to bracket mess. Press bracket on porcelain surface using bracket holder, clean excess residue, and for the last step do light-curing for 20s.
The steps for porcelain treatment in Group III: First, apply 9% hydrofluoric acid for 90s, rinse with aquades for 5s, then dry with air spray on the dental unit for 5s. After those steps, apply Ortho Solo on porcelain surface and apply Grenglo adhesive to bracket mess. Press bracket on porcelain surface using bracket holder, clean excess residue, and for the last step do light-curing for 20s.
The steps for porcelain treatment in Group IV or controlled group: First, apply Single Bond, light-curing for 10s, then apply Grenglo adhesive to bracket mess. Press bracket on porcelain surface using bracket holder, clean excess residue, and for the last step do light-curing for 20s.
After the bracket was attached to the porcelain surface, each group was placed in a plastic container and soaked in artificial saliva with pH value of 6.5 which was then placed in an incubator at 37°C for 24h.
Bracket bond strength test was conducted using Universal Testing Machine Autograph with crosshead speed of 0.5 mm/min. The value of shear strength was converted to Newton units, then to MPa.
Shear strength formula
The shear strength formula is given as follows:
After bracket bond strength test was conducted, adhesive remnant index (ARI) was calculated using ×32 magnification stereo light microscope to see the remnants attached to porcelains surface.
There are four scores according to Artun and Bergland: score 0 (no resin attached to porcelain surface), score 1 (less than half of resin attached to porcelains surface), score 2 (more than half of resin attached to porcelains surface), and score 3 (all resins are still attached to porcelain surface and the printed base bracket can clearly be seen).
After the adhesive remnants were cleaned using tungsten carbide bur, scanning electron microscope (SEM) was conducted on porcelain surface before and after treatment using FEI US, Hillsboro, OR, USA [Figure 1].
All data were analyzed statically using Statistical Package for the Social Science (SPSS) software, version 20 (IBM Corp., Chicago, IL, USA). Kolmogorov–Smirnov test (P > 0.05) was used to investigate the data distribution in this study. The homogenous of data was tested by Levene’s statistic test (P < 0.05). All data were heterogenous continued with Kruskal–Wallis test to analyze the difference in shear bond strength (P < 0.05). In addition, the comparison between the shear bond strength among groups was tested by using Wilcoxon Mann–Whitney test (P < 0.05).
| Results|| |
The Kolmogorov–Smirnov test result showed normal distribution data in each group (P > 0.05) [Table 2]. The result of Levene’s test showed that the data were heterogenous (P = 0.001; P < 0.05) so that Kruskal–Wallis test was used to see if there were any difference in shear bond strength. Shear bond strength between groups were found significantly different (P = 0.001; P < 0.05). The shear bond strength among groups using Wilcoxon Mann–Whitney test can be seen in [Table 3]. There was no difference in ARI in all groups (P = 0.140; P > 0.05). Meanwhile, adhesive remnant score attached to porcelain surface can be seen in [Table 4]. The result of energy-dispersive X-ray on chemical composition contained in porcelain, namely silica (SiO2) and feldspar (K2O.Al2O3.6SiO2) can be seen in [Table 5]. SEM analysis with ×1000 magnification showed that Group I has wide and deep microporosity, Group II has microporosity that creates groups of pores, Group III has shallow microporosity, and Group IV has a few and shallow microporosity [Figure 2]. SEM analysis with ×5000 magnification showed that Group I has deep porosity resulting in corrosion in certain area (area Y). The porosity tends to be a single pore and it still leaves area with no pores and corrosion (area X); Group II has small pores that are evenly distributed in all areas and are in groups; Group III has shallow porosity; Group IV has single and shallow porosity. There were areas with no pores [Figure 3].
|Figure 2: Observation on (A, B, C, D) scanning electron microscope (SEM) with ×1000 magnification|
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|Figure 3: Observation on (A, B, C, D) scanning electron microscope (SEM) with ×5000 magnification|
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| Discussion|| |
In this study, we found that Group I has the highest shear bond strength because bond strength on porcelain is better with the additional of silane application after the application of hydrofluoric acid as hydrofluoric acid has an ability to form chemical interlocking between inorganic material (porcelain) and organic surface (adhesive materials). Group III has the second highest shear bond strength. This occurs because there is no significant difference of bond strength of the adhesive attached to porcelain surfaces either applied with silane or without silane. This result is in accordance with the research of Alakus and Ergül. Group II has the third highest shear bond strength. The silane concentration on single bond is not compatible with the hydroxyl group formed on porcelain surface, which eventually interferes the penetration of the adhesive material into the microporosity formed by the hydrofluoric acid. The result of this study is in accordance with the results of research conducted by Zaghloul et al. Group IV has the lowest shear bond strength. This occurs due to the absence of microporosity from 9% hydrofluoric acid resulting in no micro retention on the porcelain surface. The silane concentration on a single-bond universal is incompatible with the hydroxyl group formed on the porcelain surface. The treatment after the ARI test was to clean the residual remnants using tungsten carbide bur. According to Karan et al., the use of tungsten carbide bur for cleaning the residual remnants which is then followed by performing an observation using SEM results in minimal damage compared to the use of other tools such as diamond bur, ultrasonic scaler, and adhesive remover plier.
The result of SEM observations before treatment shows smooth and homogeneous surface. In addition, there are no porosity and no cracks on porcelain surfaces. The results of SEM observation after treatment at ×5000 magnification on Group I showed the existence of wide and deep porosity, corrosion in certain area, and the porosity formed tends to be a single porosity and areas without corrosion. The existence of some areas that are not corroded is due to the silane layer that can protect porcelain surface. The non-corroded area is covered by adhesive because of strong mechanical bonds and chemical bonds of the silane. Silane can penetrate the porcelain surface and break the hydrogen bonds, thereby increasing the wetting and allowing the adhesive material to penetrate into the microporosity on the porcelain surface to produce a better chemical bond. SEM result of Group I showed no damage and cracks on the porcelain surface.
SEM result of Group II with ×5000 magnification showed evenly distributed microporous area in clusters. Furthermore, there is no flat area and almost all areas treated are corroded. This indicates that single bond is not suitable to be used for bracket attachment on porcelain crown. The result of this research is consistent with the results of Zaghloul et al.’s research, which states that silane and MDP (methacryloxydecyl phosphate) concentrations in a single universal single bond are incompatible with the hydroxyl group formed on porcelain surfaces which will eventually interfere the penetration of adhesive material into microporosities formed by hydrofluoric acid which resulting in micromechanical retention and hydroxyl group formation on porcelain surfaces. The SEM result showed no damage and cracks on the porcelain surface.
The result of SEM of Group III with ×5000 magnification showed evenly distributed and shallow microporous areas because there is no chemical bonding of silane. The SEM result showed no damage and cracks on the porcelain surface. The result of SEM of Group IV with ×5000 magnification showed a rough porcelain surface because of the application of single bond and debonding procedures (residual cleansing). Hydrofluoric acid used in porcelain greatly increases bond strength due to its ability to react with the silica phase to produce micromechanical retention on porcelain surfaces. Group IV does not use hydrofluoric acid so there is no good microporosity on the porcelain surface. The SEM result showed no damage and cracks on the porcelain surface. The results of this research can also be used to support further research on other materials containing silane. This research can be used to support clinical procedure on metal bracket strength on porcelain surface. Porcelain surface can be made rougher by using bur or sandblasting as a substitute of hydrofluoric acid. Careful use of hydrofluoric acid is required to avoid mucus irritation in the mouth.
Group I has the highest of bracket bond strength 8947MPa. Single bond is not good to be applied to bracket bond strength on porcelain; separated use of hydrofluoric acid and silane can increase shear bond strength. The group with the best SEM result is Group I that used silane and that the four groups showed no fractures.
We acknowledge Department of Orthodontic, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
Ethical policy and institutional review board statement
Declaration of patient consent
Data availability statement
Data can be available with corresponding author mail.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]