Comparative evaluation of enamel surface smoothness and operating time after debonding using four remnant adhesive removal techniques—An in vitro study

Lamis K Mohammed; Issam M Abdullah; Arkan M Al Azzawi; Hasan S Hasan; Kasem A Abeas

doi:10.4103/jioh.jioh_102_22

ORIGINAL RESEARCH

Year : 2022 | Volume : 14 | Issue : 5 | Page : 500-508

Comparative evaluation of enamel surface smoothness and operating time after debonding using four remnant adhesive removal techniques—An in vitro study

Lamis K Mohammed¹, Issam M Abdullah¹, Arkan M Al Azzawi¹, Hasan S Hasan², Kasem A Abeas¹
¹ Department of Orthodontics, College of Dentistry, Babylon University, Al-Hilla, Babil, Iraq
² Orthodontic Department, Azadi Dental Teaching Center, General Directorate of Hawler-Ministry of Health, Erbil, Iraq

Date of Submission	08-May-2022
Date of Decision	26-Jul-2022
Date of Acceptance	26-Jul-2022
Date of Web Publication	31-Oct-2022

Correspondence Address:
Dr. Hasan S Hasan
Orthodontic Department, Azadi Dental Teaching Center, General Directorate of Hawler-Ministry of Health, Erbil
Iraq

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jioh.jioh_102_22

Abstract

Aim: To compare and evaluate the effect of using four remnant adhesive removal techniques after bracket debonding on enamel surface smoothness and to assess the operating time spent in each one. Materials and Methods: Orthodontic adhesive material was removed from the buccal surface of 40 maxillary premolars after bracket debonding with four techniques as 10 teeth per each one: TCG = 10; TCPG = 10; EFG = 10; and EFPG = 10. The operating time required for the completion of each technique was recorded in seconds using a stopwatch, and the mean values of it were statistically calculated; ANOVA and least significant difference tests for means and significant difference of it were done. The enamel surface of two samples from each group in addition to the control group was evaluated by using scanning electron microscopy (SEM), and Enamel Damage Index (EDI) was used for assessing enamel surface damage by using ImageJ software. Results: Depending on the SEM evaluation and EDI, the results are as follows: EFPG was smooth enamel surface; EFG was an acceptable surface smoothness with very fine scratches; TCPG was surface with slightly coarse scratches, whereas TCG was surface with sever roughness and coarse scratches that can be seen by a naked eye. The operating time for cleanup with EFG was the lowest value among the four techniques (22.116 s) and significantly (P < 0.05) shorter than the TCPG and EFPG. Conclusions: The enhance finishing and polishing systems were considered as efficient techniques for removing the remnant adhesive materials after bracket debonding leaving a smooth surface with little or no scratches with the shorter operating time in EFG among the four techniques, whereas TCG was the worst one as it left the enamel surface with wide, deep grooves and scratches, and it is advised to stop and avoid using it anymore.

Keywords: Adhesive, Disc, Orthodontic Adhesive material

How to cite this article:
Mohammed LK, Abdullah IM, Al Azzawi AM, Hasan HS, Abeas KA. Comparative evaluation of enamel surface smoothness and operating time after debonding using four remnant adhesive removal techniques—An in vitro study. J Int Oral Health 2022;14:500-8

How to cite this URL:
Mohammed LK, Abdullah IM, Al Azzawi AM, Hasan HS, Abeas KA. Comparative evaluation of enamel surface smoothness and operating time after debonding using four remnant adhesive removal techniques—An in vitro study. J Int Oral Health [serial online] 2022 [cited 2023 Mar 23];14:500-8. Available from: https://www.jioh.org/text.asp?2022/14/5/500/359961

Introduction

The challenge for almost all the orthodontists after the finishing of each case treated orthodontically by a fixed appliance is to preserve and return the same texture, appearance, smoothness, and original condition of the enamel surface for all the orthodontically treated teeth, which have it before the orthodontic therapy. So once the orthodontic therapy is completed, the debonding or the removing of the orthodontic brackets and the remnant of adhesive materials should be done.

The aims of the orthodontic bracket’s removal are to separate not only the base of the bracket from the tooth but also any remaining adhesive material to restore, as mentioned previously, the same condition prior to the orthodontic treatment. However, this is not always possible and may lead to mechanical removal of the enamel, endangering healthy dental structure and providing irreversible damage to the enamel specially with ceramic brackets. According to some authors,^[1] this damage can be reduced depending on several factors such as the instruments used for bracket debonding, methods for residual adhesive material removal, the types of adhesive used, and the operator’s skill.

Many studies have been worked on to discover an acceptable remnant adhesive material cleanup technique with a little damage to the enamel of the tooth surface after orthodontic braces debonding such as hand scaler, ultrasonic scaling, intraoral sandblasting, sandpaper discs, stainless steel burs, diamond burs, tungsten carbide burs (TCBs) (various: flutes, grit at low or high speed), rubber cups, lasers, and various composite burs.^{[1],[2],[3],[4],[5]} Other studies tested numerous finishing and polishing procedures including a diamond bur, a TCB, polishing cups with pumice, renew Finishing System Point, and Diagloss polisher.^[1],[5],[6]

According to the studies of some authors,^[2],[7] one of the most common methods of removing residual adhesive material from the tooth surface after orthodontic bracket debonding is using a TCB at a low speed, whereas the study of the author^[8] stated that the conventional carbide burs may scratch the enamel because of the shape and sharpness of their blades. The study of authors of reference^[1] found that a TCB is an efficient (least time consuming) surface cleaning method as the original enamel roughness did not change significantly. However, these types of burs required following a secondary polishing treatment according to the studies of some authors,^[9],[10] and this was proven by the authors of references^[6],[11] as their studies discovered that the smoothest enamel surface could be obtained by using a 12-bladed TCB, followed by polishing with Sof-Lex disc for adhesive material removal, despite the findings by the authors,^[12] which clarified that there was no significant difference in the enamel loss between the TCB and Sof-Lex disc protocols, whereas the study of authors of reference^[13] discovered, according to the scanning electron microscope (SEM) images, that the Sof-Lex discs when used alone could produce the smoothest tooth surface.

Recently, several new and more conservative multiple and one-step systems for enamel cleanup after orthodontic bracket debonding such as One-Gloss polisher and Super-Snap discs,^[14] Stainbuster bur, enhance finishing point and pogo polishing, one-gloss bur and Sof-Lex disc and wheels^[15] have been developed and introduced into the orthodontics clinics.

There are several techniques available to evaluate the damaging or losing in the enamel surface after the orthodontic bracket debonding such as SEM, stereo microscopy, contact profilometry, a noncontact white light 3D profilometry, or atomic force microscopy.^[5],[16] The SEM represents a qualitative method that consists of subjective observations of the enamel surface following the debonding.

Based on the principle of preserving the original enamel surface condition at the end of orthodontic therapy after the bracket debonding and in order to select a suitable orthodontic adhesive material removal technique with low cost and less time among the oldest common conventional ones and the most updating ones, this study was aimed to compare and evaluate the effect of using four remnant orthodontic adhesive material removal techniques after the bracket debonding on the enamel surface smoothness and to assess the time spent to remove the remnant adhesive material in each one of them.

Materials and Methods

Setting and study design

The type of this study is an in vitro study, which was carried out in the laboratory of the Department of Orthodontics at the Dentistry Teaching Hospital of Faculty of Dentistry, University of Babylon, Iraq.

The study was started on December 20, 2018, and ended on April 25, 2019, including the period of samples and data collections.

Sampling criteria

The sample selection method for this study was based on the direct and clinical vision of the extracted maxillary first premolar teeth. The selection and inclusion criteria included any human maxillary first premolars extracted from patients at the range of 14–25 years of age for orthodontic purposes with (1) intact and sound buccal surface, (2) the absence of cracks and any decay in the crown of the teeth, and (3) no previous insinuation to any adhesive materials, restorations, or chemical agents.^{[1],[14],[15]}

The exclusion criteria included any extracted human maxillary first premolars with (1) carious lesions, (2) restorations, (3) visible cracks, and (4) hypoplasia.^{[1],[14],[15]}

Sampling method

A total of 45 human maxillary first premolar teeth extracted from patients at the range of 14–25 years of age for orthodontic purposes with the inclusion criteria were collected and selected for this study, and the sample size in this study was calculated depending on Steven K. Thompson equation,^[17] which is n = N × p (1−p)/[[N−1 × (d² ÷ z²)] + p (1−p)],

where n = sample size (45), N = total extracted available teeth (180), Z = confidence level at 95% (1.96), d = error proportion (0.05), p = probability (50%).

Sample preparations

After each extraction, the selected teeth were cleaned with flowing water, and tissue debris was removed with scalpel. Then, teeth were stored at a room temperature in distilled water containing 0.1% thymol crystals to inhibit bacterial growth and to prevent the dration until their use.

Each tooth should be framed vertically in self-polymerizing acrylic resin block; for that use an aluminum container in which the tooth built in this container by using sticky wax and the teeth placed so that the middle third of the buccal surface is positioned to be parallel to the container; then the mixture of self-polymerizing acrylic resin poured around each tooth to the height of the cementoenamel junction.^[18],[19]

The 45 acrylic blocks of the extracted maxillary first premolar teeth were divided arbitrarily into five groups to assess the effect of four remnant adhesive removal and enamel polishing techniques on the enamel smoothness, as shown in [Table 1].

Table 1: Distribution of groups according to the technique applied for the removal of adhesive remnant and enamel polishing

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Then the buccal surfaces of the teeth in each group were polished with fluoride-free pumice (PD, Produits Dentaires SA, Switzerland) and rubber cup in a low-speed hand piece for approximately 10 s and then rinsed with water spray for 10 s and dried with oil/moisture-free compressed air spray for 20 s.^[1]

Out of 45 samples, five served as untreated controls, 40 samples were etched for 20 s with 37% phosphoric acid gel (Super etch SDI), rinsed with water spray for 20 s, and dried with oil/moisture-free compressed air spray until the etched surfaces appeared chalky white,^[1] followed by primer (Resilience Light-Activated Orthodontic Bonding Systems—Ortho Technology, Inc, USA) application on the buccal surface of the tooth and curing for 10 s.^[15]

In order to be ensured of leaving all the adhesive material on the tooth surface, to allow for easily separation of the bracket from the tooth surface during the debonding by the bracket removal plier, and to prevent the adhesion of composite material to the base of bracket, a thin layer of Vaseline was applied on the mesh of the brackets.^[15]

A total of 40 maxillary first premolar metal orthodontic brackets with 0.022-inch slot (STRATUS Bracket Systems) were used according to the manufacturers’ company instructions (Fairfield Orthodontics, USA), so that the bracket’s base was put in the center of the buccal surface of the crown of the tooth, exactly at the midbuccal point mesiodistally with the long axis of the tooth and bonded with Resilience Light-Activated Orthodontic Bonding Systems (Ortho Technology, Inc, USA),^[14],[20] so that the bracket with the adhesive material on its base firmly pressed in its exact center point to fit perfectly, and getting uniform resin layer in all samples, the excess resin removed from the bracket base borders by dental explorer, and then curing carried out from mesial and distal surfaces for about 10 s (total 20 s) by using a light-curing device with an intensity equal to 1000–1200 mW/cm² using Woodpecker Dental Curing Light LED C (Guillin Woodpecker Medical Instrument Co., Ltd., China).^[1] All bonding steps were done by the same operator.

After light curing, all samples were kept in distilled water at 37°C for 24 h to allow for the polymerization of resin. The brackets were separated from the teeth surfaces by gently squeezing the mesial and distal wings using a bracket removal plier (Dentaurum, Pforzheim, Germany),^{[1],[15],[20]} and all the samples were examined by a naked eye to ensure that almost all adhesive material remained on the buccal surface of the tooth; otherwise it should be excluded. Fortunately, none of the samples were excluded. Then the operator, who performed the bonding and the debonding procedures, used four techniques to remove the remnant adhesive material and to polish the enamel surface as follows:

Tungsten carbide round bur group (TCG): Kerr BluWhite precision tungsten carbide (TC) round bur (LA7) was used in a low-speed hand piece without water cooling to remove the adhesive remnant for each sample in TCG (n = 10).

Tungsten carbide round bur with polishing by pumice and rubber cups group (TCPG): Kerr BluWhite precision TC round bur (LA7) was used in a low-speed hand piece without water cooling to remove the adhesive remnant for each sample in TCPG (n = 10), followed by polishing the buccal surfaces with fluoride-free pumice (PD, Produits Dentaires SA, Switzerland) and new rubber cup for every tooth by using a low-speed hand piece.

Enhance finishing disc group (EFG): Dentsply Sirona enhance finishing disc (new disc for every tooth) was used in a low-speed hand piece with pressure on the buccal surface and moisture-free compressed air cooling to remove the adhesive remnant for each sample in EFG (n = 10).

Enhance finishing polishing system group (EFPG): First, Dentsply Sirona enhance finishing disc (new disc for every tooth) was used in a low-speed hand piece with pressure on the buccal surface and moisture-free compressed air cooling to remove the adhesive remnant for each sample in EFPG (n = 10), followed by polishing the buccal surfaces with Prisma gloss composite polishing paste and new enhance polishing cups (Dentsply Sirona) for every tooth by using a low-speed hand piece.

The complete cleanup of adhesive materials in each technique was confirmed by a visual examination under the light of a dental operating unit followed by tactile assessment using a dental explorer.^{[1],[15],[20]} The time required for the completion of each adhesive material removal technique was recorded in seconds and part of a second using a digital stopwatch. Then the data of the time that were obtained and recorded were subjected to statistical analysis.

Qualitative observation and analysis method

After the removal process of the remnant adhesive materials with four techniques was completed, out of each group, two samples were subjected to qualitative enamel surface evaluation that was performed using SEM (Quanta 450, FEI Company, Czech) with accelerating voltage of 20 kV, at a working distance of 100 μm with an image magnification of 500× to compare and evaluate the enamel surface smoothness of five groups.^[15],[20]

In the SEM analysis, the teeth were dried with air stream to reduce their humidity as it effects the electron microscopy machine; then the teeth were mounted on a rectangular aluminum slide and subjected to SEM observation.^[15],[20]

ImageJ software was used for image analysis. Enamel Damage Index (EDI) was used for assessing enamel surface damage.

ImageJ is an image-processing program that can calculate area and pixel value of user-defined selections. During the analysis, images were magnified, and after 10 mm distance had been defined on the ruler of the photographic setting; the scale was adjusted to pixels/mm for size accordance.^[15],[21]

EDI according to the studies of authors^[15] includes four scores: score 0 indicates smooth enamel surface without the presence of scratches. Perikymata may be seen on enamel surface. Score 1 indicates an acceptable enamel surface with fine scattered scratches that involves 1%–10% of the enamel surface. Score 2 indicates a rough enamel surface with several coarse scratches or minor grooves that may involve 11%–50% of the enamel surface. Score 3 indicates coarse scratches or wide grooves that may involve more than 50% of the enamel surface. Enamel damage in this score is visible with a naked eye.

Statistical analysis

All the obtained data of the current study were imported into SPSS version 24 (2016) computer program for their analysis. The statistical tests that are used to analyze the data and assess the results included the following:

(a) Descriptive statistics:
- 1. Mean
- 2. Standard deviation (SD)
- 3. Minimum (min) and maximum (max) values.
(b) Inferential statistics: For parametric data:
- 1. ANOVA test: to compare the means for groups’ differences
- 2. Least significant difference (LSD): to assess the significant difference in means between every possible pair of the studied groups.

In the comparison of significance, a level of P value of about P ≤ 0.05 was considered statistically significant.

Results

The mean value of the time spent to remove the remnant of adhesive material in all groups is shown in [Table 2], in which the lowest mean value of the time was in EFG (22.116 s), which gradually increased in TCG (22.336 s) and TCPG (31.128 s) till it reaches the highest one in EFPG (31.326 s).

Table 2: Descriptive information of the mean values of the operating time required to remove the remnant of adhesive material(s) in four groups (TCG, TCPG, EFG, and EFPG), and P values (ANOVA test) for the difference of the mean of it between the four groups

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A one-way ANOVA test of the operating time required for the removal of the remnant of adhesive material displayed an F value of 7.171 and a P value of 0.001, which indicated a significant difference (P < 0.05) between groups, as shown in [Table 2].

According to the LSD test for the difference between groups (TCG, TCPG, EFG, EFPG) [Table 3], it shows that the operating time for cleanup with EFG system was significantly (P < 0.05) shorter than that of the TCPG and EFPG. Similarly, the operating time for cleanup with TCG was significantly (P < 0.05) shorter than that of the TCPG and EFPG, whereas there was no significant difference between TCG and EFG, nor between TCPG and EFPG as P values (P > 0.05).

Table 3: Statistical significance of difference in mean of operating time between every possible pair of groups (TCG, TCPG, EFG, and EFPG) assessed by LSD

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The qualitative observations and SEM analysis of the enamel surfaces after the use of four different techniques for removing the remnant adhesive material (TCG, TCPG, EFG, and EFPG) are shown in [Figure 1]A–D. Figure E shows the SEM analysis of the intact enamel (control group).

Figure 1: Scanning electron micrographs of enamel surfaces at 500× magnification: After cleanup with: (A) tungsten carbide round bur; (B) tungsten carbide round bur and polishing with pumice; (C) enhance finishing system; (D) enhance finishing and polishing system. (E) Intact buccal surface without any intervention—control group

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The result of the EDI analysis for the SEM of the enamel surface of the four groups was: score 0 was observed in EFPG (enhance finishing and polishing system group), which showed a smooth surface without the presence of scratches (enamel damage [ED] less than 1% of the enamel surface). Score 1 was noted in EFG (enhance finishing system group), which showed acceptable surface smoothness with very fine scratches (ED less than 10% of the enamel surface). Score 2 was noted in TCPG (TC round bur and polishing with pumice group), which showed slightly coarse scratches and wide grooves (ED less than 50% of the enamel surface). Score 3 was noted in TCG (TC round bur group), which showed coarse scratches and wide grooves (ED more than 50% of the enamel surface) [Table 4].

Table 4: EDI scores of the enamel surface of two randomly selective samples of each group (TCG, TCPG, EFG, and EFPG)

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In the TCG, the use of TC round bur resulted in sever roughness and irregularity of the enamel surface in SEM evaluation, showing horizontal wide grooves and scars of almost all the enamel surface [Figure 1A], and the irregularity of the surface can be seen by a naked eye when observing the tooth under the light of the dental unit. This technique appears to be inefficient for cleaning the teeth surfaces after the bracket debonding.

In the TCPG, the use of TC round bur that is followed by polishing the enamel surface with pumice by using rubber cup resulted in a decrease in the irregularity of the enamel surface in SEM evaluation, showing small grooves or scars of less than half of the enamel surface, and it is less than that shown in the previous group [Figure 1B].

In the EFG, the removing of the residual adhesive material with enhance finishing disc showed relatively smooth surface with little scratches lines seen in the diagonal direction [Figure 1C], and when observing the tooth surface directly by a naked eye under the light of the dental unit, it appeared smooth with glassy appearance. This technique appeared to be somewhat efficient in cleaning the enamel surface after the debonding of brackets, in addition to the technique that needs the less operating time if compared with the other three techniques that are used in this study.

In the EFPG, the removing of the residual adhesive material with enhance finishing disc that followed by polishing the surface with Prisma gloss composite polishing paste by using enhance polishing cup results in a smooth and relatively homogeneous enamel surface with a less number of vertical scratches on the enamel surface [Figure 1D], and when observing the tooth surface directly by a naked eye under the light of the dental unit, it appears smooth with more glassy appearance if compared with the EFG. So, this technique also can be considered as an efficient method in cleaning the enamel surface after the debonding of brackets such as the EF technique, but it needs the highest amount of operating time if compared with the other three techniques that used in this study, in addition, to be unable in removing the scratches on the enamel surface produced by the EF disc.

Discussion

The examination of tooth compositions at the submicron and nanometer levels is necessary to find out the complex surface topography and failure modes of the advanced technologies, and despite that SEM can supply only a subjective and nonquantifiable information,^[22] but the effectiveness of different methods, system, and burs on the topography and morphology of the tooth surfaces is best to check under SEM. In this study, SEM was used to check the changes on the enamel surface after using different rotary burs for residual adhesive material removal after debonding, and an operating time was recorded to discover the time required for every technique.

The challenge for all the orthodontist at the end of any orthodontic treatment, in addition to preserve the new relationship, alignment, and leveling of the teeth and to prevent the relapse of them, is to remove the remnant of orthodontic adhesive material without removing too much layers of the enamel surface and to return the same texture, appearance, and smoothness of the original condition of the enamel surface for all the orthodontically treated teeth for esthetic important and for withstanding and decreasing the demineralization susceptibility that may be increased and result from rough enamel surface, which in turn facilitates the bacterial plaque adhesion, and as a result of its acidic production, the value of pH will be decreased and that will lead to chemical dissolution of mineralized hard tissue and facilitate the dental caries.^[17]

For the cleanup process of the remnant of orthodontic adhesive material, the diamond-finishing bur and TCB were previously reported to be used for removing the remnant adhesive material, but these burs should not be used alone after orthodontic debonding processes for removing the remnant adhesive material as abrasion lines were seen after the use of these burs, which mean the increase in the roughness on the enamel surface; therefore, a secondary polishing instrument and technique should be used later,^[9],[10] that mean the operator needs an additional time to complete the procedure of cleaning and removing the remnant adhesive materials after the orthodontic debonding process to get a smooth enamel surface.

TCBs are available in various sizes, shapes, and different grits. In this study, Kerr BluWhite precision TC round bur (LA7) was used in a low-speed hand piece without water cooling to remove the adhesive remnant materials to investigate and demonstrate both its efficiency in cleaning process and its effect on the enamel surface and to compare it with other types of TCBs used in the recent studies,^[1],[20] when it used alone or followed by polishing system.

The operating time for each cleanup procedure is considered as an important factor in addition to its efficiency in getting a smooth enamel surface, so depending on this important point and to decrease the time and the steps need to get a smooth enamel surface, in this study, the Dentsply enhance finishing disc was used in a low-speed hand piece with pressure and air cooling to remove the adhesive remnant materials as a one-step technique to investigate and demonstrate both its efficiency in the cleaning process and its effect on the enamel surface and to compare it with other types of Dentsply enhance finishing tips that used in the other study,^[15] when it used alone or followed by polishing system.

The result of the operating time in this study shows that the lowest consuming time value was spent with the EFG (22.116 s), and according to the qualitative evaluation of the SEM and the EDI analysis for the SEM of the enamel surface, it appears that the EF system results in an acceptable enamel surface smoothness with very fine scratches, and this qualitative result of surface smoothness that is achieved with EF system is agreed with those obtained by the authors^[15] as the SEM of their study showed that the enhance and pogo system was less destructive to the enamel surface than the One-Gloss system and Sof-Lex disc and wheels, and the EDI of their study showed score 1 in the enhance and pogo system group, which showed acceptable surface with fine scratches. In our study, the EF system technique was used in a low speed with pressure on the buccal surface of the tooth and air cooling in order to reduce the heat generation and its thermal effect on the pulp of the tooth.

In this study, although the highest operating time value was spent with EFPG (31.326 s), but according to the qualitative evaluation of the SEM and the EDI analysis for the SEM of the enamel surface, it appears that the EFPG system results in a smooth enamel surface without the presence of scratches (score 0, ED less than 1%), which is the result that all orthodontists searching for it. The result of the surface smoothness achieved with EFP system is similar to those obtained using Stainbuster bur in the study of authors of reference^[15] as the SEM of their study stated that the Stainbuster bur seemed to be a very efficient method to clean up the surface as the Stainbuster group according to the EDI shows score 0 in which the tooth surface will be smooth without the presence of scratches.

In this study, the operating time for TCG (22.336 s) was significantly shorter than that for TCPG and EFPG, but the enamel surface appearance was the worst in it according to the SEM evaluation and EDI analysis for the SEM of the enamel surface as it is shown that the use of TC round bur caused coarse scratches and wide grooves (score 3, ED more than 50%), and this result comes in agreement with that obtained by the authors^[1],[20] as they found the use of 12-blade TC bur high speed (G12H) in the cleanup process of adhesive material after debonding can produce the deeper scratches on the enamel surface when compared with other methods that used in their study, and the operating time for this method (G12H) in the study of authors of reference^[1] was 23.5 s, which nearly the same operating time for TC round bur group that is used in our study, although they used G12 with high speed, whereas we used TC round bur with low speed. This similarity in the results of the operating time and the effect on the enamel surface between their study and our study may come from the difference in the size, shape, and grit of the TCBs, but here we should explain that the authors of reference^[1] clarified that the protocols of involving 12-blade TCBs at low and high speed can produce similar results considering Ra., and despite that Rz parameter was markedly affected when the 12-blade TCB was used at high speed and produced deeper scratches in the SEM evaluation, but statistically no significant difference was noticed for both roughness parameters (ΔRa and ΔRz) between G12L and G12H, whereas the operating time for G12H in the study of author of reference^[20] was only 8.414 s, which is significantly much lesser than the operating time of TCG in our study; this difference may result from the difference in the speed of air motor that used in each study as in our study, we used TC round bur with low speed, whereas the authors of reference^[20] used 12-blade TCB with high speed and water cooling, which may be much higher than the speed that used in the study of authors of reference^[1]. The result of the enamel surface appearance with TCG of the current study was the worst as mentioned previously, which disagreed with results of the authors of reference^[6], as they reported that the carbide burs at high speed were found to be efficient in residual resin removal.

In the current study, although the operating time for the TCPG was nearly the same of that for EFPG (31.128 s, which is slightly less than that of EFPG with no significant difference between them), and despite that both techniques (TCPG, EFPG) were performed in two steps: the first step includes the removing of the remnant adhesive materials with TC round bur in the first one and EF disc in the second one, and the second step involves polishing the surface of the tooth by using PD pumice with rubber cup in the first one and Prisma gloss composite polishing paste with enhance polishing cup in the second one, the result of the SEM and the EDI analysis for the SEM of the enamel surface was significantly differed as the TCPG showed that score 2 ED represents less than 50% of the enamel surface including slightly coarse scratches and wide grooves, whereas EFPG showed score 0, ED less than 1%, and results in a smooth enamel surface without the presence of scratches. This result may make us reach to the concept that the polishing of the enamel surface of the teeth with pumice following the use of TC round bur may result in a decrease in the area and the depth of grooves and scratches on the enamel surface that result from the use of TC round bur as the EDI was declined from score 3 in TCG to score 2 in TCPG as mentioned previously in the result of this study, but it takes more operating time with significant difference.

Many previous studies^{[2],[3],[6],[8],[23],[24]} explained that the sequential use of multiple tools for polishing is more efficient than one-step procedures in terms of reduction in surface roughness, whereas our findings in this study clarified that the use of one-step technique (EF system technique) was efficient in removing the remnant of adhesive materials after the debonding with the least operating time among the other three techniques used in this study and can result in an acceptable enamel surface smoothness with very fine scratches and ED less than 10% of the enamel surface, that mean our finding disagreed with those of the previously mention studies.

The authors^[1],[20] explained the relationship between the operating time spent on removing the remnant adhesive materials and the change in roughness of the enamel surface as the longer operating time spent on removing the remnant adhesive material; the less was the roughness stayed on the enamel surface; this concept according to our findings in this study is inaccurate and not necessarily correct, because this concept has two possibilities, either right or wrong, as the degree of surface smoothness or roughness is a multifactorial issue, in addition to the effect of the operating time on it, but also the type and size of the rotary instruments that used in removing the residual adhesive material after the debonding are very effective factor on it; for example, in our study, the concept of the correlation between the time and the roughness degree is misconception if applied to the TCPG, as although this technique was of two steps with a longer operating time if compared with that of TCG and EFG, but it results in an enamel surface with slightly coarse scratches and wide grooves and ED involved less than 50% of tooth surface, whereas it will be a correct concept if applied to EFPG, as this technique was of two steps with the longer operating time among the four techniques used in this study and at the end give us a smooth enamel surface without the presence of scratches and ED involved less than 1% of the tooth surface.

Depending on the previous explanation, it turns out that it is the orthodontist’s responsibility to choose a suitable rotary instruments and technique for removing the remnant adhesive materials after the debonding with minimal damage, iatrogenic abrasions, and scratches to the enamel surface, and at the same time, it should be able to maintain the smoothness and texture of the enamel surface and return its original condition, which is considered the challenge for almost all the orthodontists after the finishing of each case treated orthodontically by a fixed appliance.

Conclusions

The enhance finishing and polishing systems were considered as efficient techniques for removing the remnant adhesive materials after the bracket debonding, leaving a smooth enamel surface with little or no scratches.

The TC round bur was considered as the worst technique among all four techniques for removing the remnant adhesive materials after the bracket debonding as it left the enamel surface with wide and deep grooves and scratches that may involve more than 50% of the tooth surface.

SEM examination displayed that enhance finishing and polishing system (EFPG) was the least damaging to enamel surface among all four techniques as it created the smoothest enamel surface that was as close as possible to the natural enamel as ED involved less than 1% of the tooth surface followed by enhance finishing system (EFG) as ED involved less than 10% of the tooth surface.

The operating time spent for removing remnant adhesive materials ranged from the least value (22.116 s) with enhance finishing group to the highest one (31.326 s) with enhance finishing and polishing group.

The correlation between the operating time and the degree of smoothness depends on a large extent on the type of the rotary instrument that select to remove the remnant adhesive materials.

Acknowledgement

The authors wish to thank the lab staff for their cooperation during the study and the orthodontic procedures.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Authors’ contributions

All the article authors had contributed in an equal manner from writing to publishing.

Ethical policy and institutional review board statement

Not applicable.

Patient declaration of consent

Not applicable.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

References

1.	Sigilião LC, Marquezan M, Elias CN, Ruellas AC, Sant’Anna EF Efficiency of different protocols for enamel clean-up after bracket debonding: An in vitro study. Dental Press J Orthod 2015;20:78-85.
2.	Zachrisson BU, Arthun J Enamel surface appearance after various debonding techniques. Am J Orthod 1979;75:121-7.
3.	Hasan HS, Elkolaly MA Updating the orthodontic envelope of discrepancy: Canines transposition. Int J Orthodont Rehab 2021;12:140-7.
4.	Eminkahyagil N, Arman A, Cetinşahin A, Karabulut E Effect of resin-removal methods on enamel and shear bond strength of rebonded brackets. Angle Orthod 2006;76:314-21.
5.	Janiszewska-Olszowska J, Tandecka K, Szatkiewicz T, Stępień P, Sporniak-Tutak K, Grocholewicz K Three-dimensional analysis of enamel surface alteration resulting from orthodontic clean-up—Comparison of three different tools. BMC Oral Health 2015;15:146.
6.	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.
7.	Brauchli LM, Baumgartner EM, Ball J, Wichelhaus A Roughness of enamel surfaces after different bonding and debonding procedures: An in vitro study. J Orofac Orthop 2011;72:61-7.
8.	Radlanski RJ A new carbide finishing bur for bracket debonding. J Orofac Orthop 2001;62:296-304.
9.	Hasan H, Hassan B Comparison of shear bond strength of edgewise bracket bonded to composite restoration by using three regimes of orthodontic adhesive systems (in vitro study). Iraqi Dent J 2015;37:32-38.
10.	Eliades T, Kakaboura A, Eliades G, Bradley TG Comparison of enamel colour changes associated with orthodontic bonding using two different adhesives. Eur J Orthod 2001;23:85-90.
11.	Alessandri Bonetti G, Zanarini M, Incerti Parenti S, Lattuca M, Marchionni S, Gatto MR Evaluation of enamel surfaces after bracket debonding: An in-vivo study with scanning electron microscopy. Am J Orthod Dentofacial Orthop 2011;140:696-702.
12.	Azzawi A, Hasan H, Nahidh M, Elkolaly M, Kolemen A A female hair clip and orthodontists’ neck-back pain perception: A survey. Int J Dent 2021;2021:1-5.
13.	Ozer T, Başaran G, Kama JD Surface roughness of the restored enamel after orthodontic treatment. Am J Orthod Dentofacial Orthop 2010;137:368-74.
14.	Fan XC, Chen L, Huang XF Effects of various debonding and adhesive clearance methods on enamel surface: An in vitro study. BMC Oral Health 2017;17:58.
15.	Shah P, Sharma P, Goje SK, Kanzariya N, Parikh M Comparative evaluation of enamel surface roughness after debonding using four finishing and polishing systems for residual resin removal—An in vitro study. Prog Orthod 2019;20:18.
16.	Banerjee A, Paolinelis G, Socker M, McDonald F, Watson TF An in vitro investigation of the effectiveness of bioactive glass air-abrasion in the “selective” removal of orthodontic resin adhesive. Eur J Oral Sci 2008;116:488-92.
17.	Elkolaly MA, Hasan HS, Foda MY MHM bracket design on the path of Dr Andrews of true straight wire technique, prototype study design. J Orthod Sci 2022;11:14.
18.	Montasser MA, Drummond JL, Roth JR, Al-Turki L, Evans CA Rebonding of orthodontic brackets. Part II, an XPS and SEM study. Angle Orthod 2008;78:537-44.
19.	Abdullah IM, Abeas KA, Mohamed LK, Abd Al-kareem AM Evaluation of shear bond strength of metal brackets in total dryness and partial dryness conditions. Indian J Public Health Res Dev 2018;9:790-3.
20.	Ulusoy C Comparison of finishing and polishing systems for residual resin removal after debonding. J Appl Oral Sci 2009;17:209-15.
21.	Livas C, Kuijpers-Jagtman AM, Bronkhorst E, Derks A, Katsaros C Quantification of white spot lesions around orthodontic brackets with image analysis. Angle Orthod 2008;78:585-90.
22.	Eliades T, Gioka C, Eliades G, Makou M Enamel surface roughness following debonding using two resin grinding methods. Eur J Orthod 2004;26:333-8.
23.	Hasan HS, Eysa AMSASA, Mahmoud MFA, Elkolaly MA Expanding the concept of orthodontic camouflage for a skeletal class II camouflage case through the use of skeletal anchorage system. Int J Orthod Rehabil 2022;13:64-74.
24.	Ryf S, Flury S, Palaniappan S, Lussi A, van Meerbeek B, Zimmerli B Enamel loss and adhesive remnants following bracket removal and various clean-up procedures in vitro. Eur J Orthod 2012;34:25-32.