|Year : 2021 | Volume
| Issue : 4 | Page : 372-377
Bond strength efficiency of a high fluoride and calcium release self-adhesive resin cement: A comparative in vitro study
Arkan Muslim Al Azzawi1, Hayder A Kadhim2, Ahmed Muhsin Yousif Al Mayali2, Mohamed Elkolaly3, Hasan Sabah Hasan4
1 Orthodontics Department, College of Dentistry-University of Babylon, Babil, Iraq
2 P.O.P. Department, College of Dentistry-University of Kufa, Najaf, Iraq
3 Orthodontic Department, Royal Dental Center, Alexandria, Egypt
4 Orthodontic Department, Khanzad Teaching Center, General Directorate of Hawler-Ministry of Health, Erbil, Iraq
|Date of Submission||24-Jan-2021|
|Date of Decision||08-May-2021|
|Date of Acceptance||12-May-2021|
|Date of Web Publication||19-Aug-2021|
Dr. Hasan Sabah Hasan
Orthodontic Department, Khanzad Teaching Center, General Directorate of Hawler-Ministry of Health, Erbil.
Source of Support: None, Conflict of Interest: None
Aim: To clarify the bond strength of Theracem in comparison to other types of adhesive material, in addition to testing the adhesive remnant index (ARI). Material and Methods: A hundred extracted human premolars were collected for orthodontic purposes. Teeth were stored in 1% Chloramine-T trihydrate as bacteriostatic/bactericidal solution for one week; then, they were transmitted into distilled water. The buccal surface of the studied teeth was kept under surveillance and mounted in acrylic block. Siamese metal pre-adjusted premolar brackets were fixed on the buccal surface using three adhesive cements: Bisco ORTHO, GC Fuji ORTHO LC (Light Cure) and Theracem. The teeth were randomly divided into five groups of 20 specimens each. Group 1 (G1) used 37% phosphoric acid gel, Bisco primer, and Bisco adhesive. Group 2 (G2) used GC Fuji ORTHO LC (Light Cure) without etching. Group 3 (G3) used GC Fuji ORTHO LC (Light Cure) with etching. Group 4 (G4) used Theracem without etching. Group 5 (G5) used Theracem with etching. All the tested specimens were kept at 370°C in a distilled water bath for 24 h. Shear bond strength (SBS) was conducted using a universal microcomputer-controlled electronic test machine. Then, specimens’ surfaces were assessed under a stereomicroscope with a 10× magnification to examine the orthodontics adhesive residue’s buccal surface and scored using ARI. Results: The G4 exhibited the lowest mean bond strength value (M = 11.24, SD = 3.52), whereas G3 yielded the highest bond strength value (M = 25.02, SD = 3.41). The variance analysis revealed F = 61.71, indicating a significant difference among the bond strength values (P < .001). Tukey HSD post hoc testing demonstrated a significant difference in bond strength among groups, except G2 with G1 and G3. Kruskal–Wallis test showed statistically significant differences among all groups (P < .001). On comparison, the least adhesives that remained on the tooth surface were in G4 and G5. Conclusion: Theracem bonding system provides many advantages, as there is no need for an acid-etching step, it is easy to manipulate, and it provides a very suitable S.B.S. with no enamel detachment during debonding. Also, scores 0 and 1 in the ARI test lead to a decrease in enamel damage.
Keywords: Brackets, Composite Adhesive, Glass-ionomer, Shear Bond Strength, Theracem
|How to cite this article:|
Al Azzawi AM, Kadhim HA, Al Mayali AM, Elkolaly M, Hasan HS. Bond strength efficiency of a high fluoride and calcium release self-adhesive resin cement: A comparative in vitro study. J Int Oral Health 2021;13:372-7
|How to cite this URL:|
Al Azzawi AM, Kadhim HA, Al Mayali AM, Elkolaly M, Hasan HS. Bond strength efficiency of a high fluoride and calcium release self-adhesive resin cement: A comparative in vitro study. J Int Oral Health [serial online] 2021 [cited 2022 Jan 29];13:372-7. Available from: https://www.jioh.org/text.asp?2021/13/4/372/324134
| Introduction|| |
Orthodontic brackets should sustain occlusal forces by suitable adhesion to the enamel, and they should reverberate in vitro by shear bond strength (SBS)., Adhesive bonded brackets might be debonded, leading to extra pension for the orthodontist and the patient being disadvantaged in terms of cost, time, and harmful effects on enamel due to adhesive bond disarmament before the bonding of new brackets.,,, Thus, efforts have been synthesized to enhance the properties of resin composites applied to bond orthodontic brackets. Currently, micro-filled, micro-hybrid, and flowable adhesive is mostly applied for orthodontic bracket fixation. Moreover, this adhesive has a high degree of polymerization contraction, less compressive and tensile bond strengths, minimum fracture strength, and indigent marginal integrity., In spite of all the material enhancements, orthodontic braces, nevertheless, collect bacterial plaque. Microorganisms’ by-products can lead to white spots or caries, gum inflammation, periodontium trouble, and high metal ion release.,,,,,,, Long-term orthodontic therapy could cause enamel surface damage or white patch lesions around orthodontic braces.,,,,, This is highly attentional in orthodontics when many patients cannot maintain sufficient good oral hygiene. Many methods and materials involve fluoride, or antibacterial agents have been used to reduce such side effects.,,,,,
Although self-etch adhesives provided a more conservative etch pattern, they could not eliminate the enamel damage and remnant adhesive retained on the enamel surface after bracket debonding. So, similar post-debonding resin removal protocol finishing and polishing were recommended for teeth conditioned with self-etch bonds; otherwise, stain susceptibility remains high, similar to that reported with the conventional acid-etching technique.,
In addition, there is a new trend toward introducing adhesives releasing the Ca ions into enamel surface that leads to caries inhibiting activity and minimizing or eliminating the development of white spot lesion.,
Wilson and Kent first introduced glass ionomer cement (GICs) as dental cement. There are many unique features of GICs dental cement, such as chemical bonds with tooth surface (enamel), dentine, and metal. Tooth surface carious spot around orthodontic brackets is the most dangerous deleterious tooth surface effect., One of the most important unique features of GICs is the right quantity of fluoride, which can release over time and that may lead to the protection of the tooth surface from decalcification., GICs also possess other unique properties that are skillfully deboned from tooth surfaces, leading to less enamel damage. Further, reinforced resin glass ionomer cement (RRGICs) production with remarkable properties combines both conventional and physical properties of composite resin., Theracem dual-cure self-adhesive resin cement has antimicrobial activities, continuous calcium, and fluoride ion release. A high level of conversion ensures a higher physical strength. Transitions occur from acidic to alkaline pH in minutes and contain 10-methacryloyloxydecyldihydrogen phosphate, thereby allowing for a strong attachment to zirconia, metal, and alumina substrate concentrations without using a primer bond.,
Many factors affecting SBS have been investigated. These factors involved acid conditioning acid concentration,, conditioning time for acid etch,,,,,,,, adhesive type,, and backing type of orthodontic brackets., This investigation is the first study that used Theracem for the bonding of orthodontic brackets. Its aim was to clarify the bond strength of Theracem in comparison to other types of adhesive material, apart from testing the adhesive remnant index (ARI).
| Materials and Methods|| |
Setting and design
This in vitro experimental study was conducted at Kufa University, Iraq, during June-December 2019. A judgment or purposive randomized sampling method was used. The selected criteria included the following: The choice teeth had grossly sound crowns, without filling, and without visible cracks or scratches, further, they had no history of exposure to chemical irritant agents, such as hydrogen peroxide or formalin. Teeth that did not have these features were excluded from the study. The sample was determined in consideration of the sample used in previous similar studies. After teeth collection according to the selection criteria, the teeth were randomly allocated into five groups.
After extraction, the 100 premolars (subdivided into five groups, comprising 20 teeth each), that had been extracted for orthodontic purposes were washed with tap water to remove the blood and residual periodontal tissues. Subsequently, the teeth were stored for one week in 1% Chloramine-T trihydrate that served as a bacteriostatic and bactericidal liquid; then, they were transmitted into distilled water for their storage. Further, the randomly chosen teeth had grossly sound crowns, with no filling, and without visible cracks or scratches; they had no history of exposure to chemical irritant agents, such as hydrogen peroxide or formalin.
The acrylic block’s teeth were mounted using two L-shaped metal plates that were assembled to construct a box (7 × 2 × 2 cm). Every four teeth were fixed on a metal plate with wax and aligned. The median part of the labial aspect was parallel to analyzing the surveyor rod to ensure that the debonding force would run parallel to the orthodontic bonded braces base. The two L-shaped plates were assembled about the fixed teeth to form a box. After mixing self-cure acrylic resin (Duracryl™ Plus, SpofaDental, Czech Republic) powder/liquid according to the manufacturer’s instructions, it was poured around the teeth up to about 1 mm apical to the cementoenamel junction. After the complete set of acrylics, the teeth were incubated in distilled water at lab temperature.
Siamese metal pre-adjusted premolar brackets (stainless steel, equilibrium® 2, Dentaurum, Inspringen, Germany) were used, with a medium base surface area (10.4 mm2). Three adhesive types of cement were used in this study:
Bisco ORTHO (composite resin; Bisco Inc., Schaumburg, III, USA)
GC Fuji ORTHO LC (light-cured RMGIC; G.C. America, Alsip, III)
Theracem (self-adhesive resin cement; Bisco, Schaumburg, IL, USA)
The labial aspects of all teeth were polished by using non-fluoridated pumice for 10 s; next, the teeth were randomly divided into five groups of 20 specimens each [Table 1].
In G1, the teeth’s labial surface was etched for 15 s with 37% phosphoric acid gel, then washed with water for 20 s, and finally dried with oil-free air for 10 s until a chalky appearance appeared. Bisco primer was applied on etched enamel and spread by a gentle airburst for 3 s into a thin film. The bracket bases were loaded with Bisco adhesive and placed in the middle of the tooth’s labial aspect. According to Nemeth et al. and Al-Shamaa, a constant weight (250g load fixed on the upper part of the surveyor vertical arm) was loaded on the bracket using a hard rubber polishing bur fixed in the lower part of the surveyor vertical arm through for 10 s to ensure that each brace will seat under an equal force, get a uniform thickness of the adhesive, and prevent air bubbling that may affect the bond strength., Adhesive bond excess was pealed out using a dental probe. The adhesive was polymerized by using L.E.D. light-curing (radii plus, S.D.I., 1500 mW/cm2 light intensity), with a 10 s exposure on each mesial and distal side of the brace.
In G2, GC Fuji ORTHO LC (Light Cure) was used for bracket bonding. After shaking and pushing the plugger inside the capsule body, it was mixed for 10 s using an amalgamator according to the manufacturer’s instructions. Then, the capsule was placed into the applier, the lever was pulled, the material was extruded into the bracket base, and it was positioned on the center part of the labial tooth surface. The bracket was pressed firmly against a tooth, and a dental probe was used for gently removing excess bonding material without affecting the accurately seated bracket. After that, each bracket was cured for 10 s from all aspects.
The selected teeth in G3 were similarly bonded by GC Fuji ORTHO LC (Light Cure) but after etching the buccal enamel with the technique mentioned earlier in G1. In G4, the braces were bonded to teeth surfaces using Theracem. After attaching the mixing tip to a material syringe and pressing the plugger, Theracem was mixed and was dispensed on the brace base. Then, the brace was seated and pressed gently against the tooth surface; any excess adhesive was removed; and finally, light-curing was conducted for 20 s.
In G5, the labial surface of enamel was etched, similar to the procedure mentioned earlier; then, Theracem adhesive cement was used for bracket bonding. The same investigator performed the bracket placement procedure for all specimens and during the same session. Subsequently, the samples were stored at 370°C in a distilled water container for 24 h before measuring the SBS.
The SBS was assessed by using a microcomputer-controlled electronic universal testing machine (Time Group I.N.C., P.R.C.), and no specimen failed during testing. Force was applied by using a chisel-shaped blade with a 0.5 mm thick edge; occlusal–gingival pressure was applied to the bracket base with a chisel-head speed of 0.5 mm/min until debonding occurred. The maximum stress was recorded [Figure 1].
|Figure 1: (A) Buccal surface parallelism of teeth using dental surveyor; (B) SBS using microcomputer-controlled electronic universal test machine|
Click here to view
After that, the specimens’ labial surfaces were assessed under a stereomicroscope with a 10× magnification, to examine the buccal surface for adhesive residue and they were scored using ARI [Figure 2].
|Figure 2: Shows the adhesive remanent index results of the five tested groups using a stereomicroscope with a 10× magnification|
Click here to view
Data analysis was performed by using SPSS software version 25. In addition to descriptive statistics, a one-way analysis of variance (ANOVA) and Tukey HSD post hoc test were performed to assess the SBS difference between groups. On the other hand, Kruskal–Wallis and Mann–Whitney tests were carried out for nonparametric data analysis (ARI score).
| Results|| |
Descriptive statistics for the five groups and SBS values (in MPa) are shown in [Table 1]. The G4 (Theracem without etch) exhibited the lowest mean bond strength value (M = 11.24, SD = 3.52), whereas G3 (GC Fuji ORTHO LC (Light Cure) with etch) yielded the highest bond strength value (M = 25.02, SD = 3.41). The variance analysis revealed F = 61.71, indicating a significant difference among the groups in bond strength values (P < .001), ηp2 = 0.772.
Tukey HSD post hoc testing [Table 2] generally demonstrated highly significant differences in bond strength among the groups, except for G2 with G1 and G3 wherein it was nonsignificant.
|Table 2: SBS (in MPa), descriptive statistics, and variance analysis of the five groups tested|
Click here to view
The ARI scores for adhesive remaining of the five groups tested are presented in [Table 3]. Using the Kruskal–Wallis test, a statistically significant difference among all groups has been reported (P < 0.001). On comparison, the least adhesives left on the tooth surface were in G4 and G5, in which the Theracem adhesive cement was used in bracket bonding [Table 4].
| Discussion|| |
Theracem dual-cure, calcium-fluoride release, self-adhesive orthodontic resin cement is used in the fixation of orthodontic appliances such as brackets and bands; it is insoluble in water and oral fluids and there is no need to apply etchant, primer, or adhesive to the prepared tooth surface. This study’s remarkable result is related to the SBS of resin-reinforced GICs and it is promising for all orthodontists to overcome the drawbacks of composite resin during bonding procedures.,
A finding of the present study is that Theracem shows an SBS of 11.24 ± 3.52 MPa for G4 Theracem without acid etch conditioning of the enamel surface; these values are enough to withstand load orthodontic brackets. The orthodontic force generally does not exceed 4.5 N for each tooth., Reynolds and von Frauenhofer stated that they found a bond strength of 5.9 to 7.8 MPa enough for main clinical orthodontic bonding techniques. In addition, according to Lopez, for successful clinical bonding, the SBS is recommended to be 7 MPa, and its usage without etching and absolute moisture control is not a critical requirement.
Furthermore, the long-term secretion of fluoride from Theracem leads to a reduction in enamel demineralization around orthodontic attachments; this is in agreement with the finding of Bishara et al. regarding GC Fuji ORTHO LC (Light Cure). The debonding procedure is more manageable with GICs, and chemical adhesion with enamel is highly advantageous. The fascinating result of SBS for G5 Theracem (acid etch conditioning of enamel surface equal to 14.33 ±2.31 MPa) agreed with that of Ali and Maroli, as they mentioned that SBS increased in the case of 37% enamel surface conditioning with phosphoric acid.
Another investigation was the finding that the SBS of GC Fuji ORTHO LC (Light Cure) in G2 without acid etch was 22.92 ± 4.21, and in G3 it was 25.02 ± 3.41. This result disagrees with that of Bishara et al., a finding that is due to their study using the upper central incisor bracket on the molars’ surface. This led to the morphological disagreement between the tooth surface and the bracket base, and SBS was logically decreased. On the contrary, this finding agrees with the result of Ali and Maroli.
The SBS of GC Fuji ORTHO LC (Light Cure) in G2 and G3 was superior to the G1 control group of Bisco resin composite. This is due to the RRGICs behaving similar to composite resin in regards to the automatically setting mechanism of the acid–base reaction between RRGICs and poly acid-modified composite resin, which is similar to the findings of Silverman et al. and Sfondrini et al.,
Also, GC Fuji ORTHO LC (Light Cure) proves to be superior to G4 and G5 of the Theracem group. This finding may be due to achieving SBS, which can vary depending on the material used and the pretreatment conditioning of the enamel surface; this agreed with the results of Sfondrini et al. and Chitnis et al.,,,,
Further, the ARI shows that Theracem has superiority reeling between score 0 and score 1 for G4 and G5 than control group G1 Bisco composite resin and GC Fuji ORTHO LC (Light Cure) reeling between all scores of ARI, this gives an advantage of Theracem over other groups, which cause most of all the materials detached from tooth surface and this is a very fascinating result for all the orthodontists those dreaming minimal touch to enamel after debonding process.
| Conclusion|| |
It has been shown that the Theracem bonding system provides many advantages: There is no need for the acid-etching step; the system is easy to manipulate, and it provides a very suitable SBS with no enamel detachment during debonding. Also, the scores 0 and 1 in the ARI test lead to a decrease in enamel damage.
Financial support and sponsorship
Conflict of interest
No conflict of interest, financial or otherwise.
Data collection was done by Arkan Al Azzawi and Hasan Sabah Hasan, analyses were done by Hayder A. Kadhim and Ahmed Al Mayali, data interpretation was conducted by Mohamed Elkolaly, and finally, the article was written by Hasan Sabah Hasan.
Ethical policy and Institutional Review board statement
Not needed in this study.
Patient declaration of consent
Data availability statement
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]