Assessment of enamel damage after removal of ceramic brackets

Performance of two laser motion modes versus conventional orthodontic ceramic brackets debonding technique on enamel surface topography

The risk of enamel deterioration that frequently coexists with debonding of orthodontic teeth brackets elevates the mandate for finding an optimum approach for debonding them without harmful effects. This in-vitro study is intended to compare the effects of two different laser modes (scanning and circular) and a conventional method on the enamel surface after debonding orthodontic brackets. 66 extracted premolars were assigned into 3 groups. After that, light-cure composite resin was used to attach the ceramic brackets to the teeth. Amongst the test groups, Group I: specimens that were debonded using conventional debonding using pliers; Group 2: specimens that were debonded using Er, Cr: YSGG laser applications using the circular motion method; and Group 3: specimens that were debonded using Er, Cr: YSGG laser applications using the scanning motion method. Adhesive Remnant Index (ARI) assessment, intra-pulpal temperature increase, enamel surface roughness after polishing, and assessment of the microstructure of enamel were carried out with scanning electron microscopy. The gathered information was examined statistically. The conventional debonding method had a significantly higher proportion of adhesive remnant index (ARI) scores of 2 and 3 in comparison to the circular (p < .004) and scanning laser groups (p < .001). There was no significant difference in ARI scores between the circular and scanning laser groups (p > .05). Moreover, the circular and scanning laser debonding methods resulted in a significantly higher proportion of Enamel Surface Roughness (ESR) scores of 0 and a lower proportion of ESR scores of 3 compared to the conventional technique group (p < .001). However, there was no significant difference in ESR scores between the circular and scanning laser methods (p = .945). Lastly, the average intra-pulpal temperature was significantly higher in the circular laser group (1.9 ± 0.5 ) compared to the scanning laser group (0.9 ± 0.2) with p < .001. Er, Cr: YSGG laser irradiation is a tool that shows promise for debonding ceramic brackets with minimal harm to the enamel surface. The scanning laser technique is more desirable due to the lower intra-pulpal temperature increase.

Structural and Color Alterations of Teeth following Orthodontic Debonding: A Systematic Review

AIM

The objective of this study was to explore the effects of fixed orthodontic appliances on enamel structure by assessing microfractures, surface roughness, and alterations in color.

METHODS

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A systematic search of online databases was conducted using the keywords 'enamel' AND 'orthodontic debonding'. Eligibility criteria included both in vivo and ex vivo clinical trials conducted on human teeth.

RESULTS AND DISCUSSION

A total of 14 relevant papers were analyzed. Various instruments and techniques were utilized across different studies to assess surface roughness, color change, and surface fractures.

CONCLUSIONS

The findings of this study suggest that ceramic brackets may lead to an increase in enamel fractures, particularly during bracket removal. The surface roughness of enamel exhibits variability depending on the adhesive substance and polishing methods used post-removal. Fixed orthodontic appliances could induce changes in enamel color, which may be alleviated by the use of nano-hydroxyapatite or specific polishing techniques. Further research is necessary to identify effective strategies for managing these color changes and improving the overall outcomes of fixed orthodontic treatment.

Teeth Microcracks Research: Towards Multi-Modal Imaging

This perspective is an overview of the recent advances in teeth microcrack (MC) research, where there is a clear tendency towards a shift from two-dimensional (2D) to three-dimensional (3D) examination techniques, enhanced with artificial intelligence models for data processing and image acquisition. X-ray micro-computed tomography combined with machine learning allows 3D characterization of all spatially resolved cracks, despite the locations within the tooth in which they begin and extend, and the arrangement of MCs and their structural properties. With photoluminescence and micro-/nano-Raman spectroscopy, optical properties and chemical and elemental composition of the material can be evaluated, thus helping to assess the structural integrity of the tooth at the MC site. Approaching tooth samples having cracks from different perspectives and using complementary laboratory techniques, there is a natural progression from 3D to multi-modal imaging, where the volumetric (passive: dimensions) information of the tooth sample can be supplemented by dynamic (active: composition, interaction) image data. Revelation of tooth cracks clearly shows the need to re-assess the role of these MCs and their effect on the structural integrity and longevity of the tooth. This provides insight into the nature of cracks in natural hard materials and contributes to a better understanding of how bio-inspired structures could be designed to foresee crack propagation in biosolids.

Effectiveness of Two Intensity Levels of Diode Laser in Debonding Metallic Brackets Regarding Enamel Surface Integrity and Pulpal Temperature: An Ex-Vivo Study

INTRODUCTION

The traditional methods of deboning metal brackets exert excessive force, resulting in enamel scratches, fractures, and patient discomfort. The objective of this study was to evaluate the effectiveness of using two intensity levels of a diode laser for debonding metallic orthodontic brackets as an alternative to the conventional debonding method.

MATERIALS AND METHODS

Sixty intact, extracted human premolar teeth were used in this study, and metal orthodontic brackets were bonded to the buccal surface of these teeth. The teeth were divided into three groups for the experiment: (1) the control group, where conventional bracket debonding was performed using a debonding plier, (2) the first experimental group, where a diode laser (2.5W, 980nm) was utilized for laser debonding, and (3) the second experimental group, where a diode laser (5W, 980nm) was used for laser debonding. The laser was applied using a sweeping movement for 5 seconds. After debonding, the adhesive remnant index (ARI), the lengths, and the frequency of enamel cracks were compared among the groups. Additionally, an increase in intra-pulpal temperature was measured.

RESULTS

In all groups, there were no instances of enamel fractures. Laser debonding resulted in a significant reduction in both the frequency and length of newly formed enamel cracks compared to the conventional debonding method. The laser debonding group exhibited increases in intra-pulpal temperature of 2.37°C and 3.60°C in the second and third groups, respectively. These temperature increases were significantly lower than the threshold of 5.5°C. There were no significant differences observed in the ARI scores among the groups.

CONCLUSION

With all debonding methods, an increase in the length and frequency of enamel cracks should be anticipated. However, laser-assisted debonding of metal brackets offers the advantage of reducing the risk of enamel damage while avoiding thermal damage to the pulp.

The influence of age and orthodontic debonding on the prevalence and severity of enamel craze lines

BACKGROUND

Craze lines may cause esthetic concerns, especially when noted on the incisors. Various light sources with additional recording apparatus have been proposed to visualize craze lines, but a standardized clinical protocol is yet to be determined. This study aimed to validate the application of near-infrared imaging (NIRI) from intraoral scans to evaluate craze lines and to determine the influence of age and orthodontic debonding on their prevalence and severity.

METHODS

The NIRI of maxillary central incisors from a full-mouth intraoral scan and photographs from an orthodontic clinic (N = 284) were collected. The prevalence of craze lines and influence of age and orthodontic debonding history on severity were evaluated.

RESULTS

Craze lines were detected reliably as white lines distinguishable from dark enamel using the NIRI from intraoral scans. The craze line prevalence was 50.7%, which was significantly higher in patients 20 years or older than in patients younger than 20 years (P < .001), with more frequent severe craze lines for those 40 years or older than in patients younger than 30 years (P < .05). Prevalence or severity was similar between patients with and without an orthodontic debonding history regardless of the type of appliance.

CONCLUSION

The prevalence of craze lines in the maxillary central incisor was 50.7%, with a higher prevalence in adults than in adolescents. Orthodontic debonding did not affect the severity of craze lines.

PRACTICAL IMPLICATIONS

Craze lines were reliably detected and documented by means of applying NIRI from intraoral scans. Intraoral scanning can provide new clinical information on enamel surface characteristics.

Comparative assessment of surface irregularities of enamel after bonding with different techniques followed by three composite removal methods: An atomic force microscopic study

Background

To compare and assess the enamel surface roughness by Atomic Force Microscopy between ceramic and metal brackets after adhesive removal with 3 different methods.

Methods

90 extracted premolars were collected and divided equally into 3 groups G, Y, and R. With group G bonded with metallic brackets (using primer and Transbond XT), group Y with ceramic brackets (primer and Transbond XT), and group R with ceramic brackets (silane and Transbond XT). Each group was subdivided into 3 sub-groups (10 premolars each) based on the resin removal method as A: 12- flute tungsten carbide (TC) bur (high speed), B: 12- flute TC bur (low speed), and C: 30 flute TC bur (low speed). Surface roughness values were calculated and compared before bonding and also after adhesive removal by atomic force microscope (AFM). Measured data were analyzed using paired student t-test, ANOVA, and Tukey's tests.

Results

Among the groups, group G showed increased surface roughness after debonding compared to group Y and group R, with Rq value showing a statistically significant difference (P<0.047). Whereas, within the subgroups, subgroup A (12-flute TC, high speed) with Rq showed increased surface roughness which was found to be statistically significant (P<0.042).

Conclusion

None of the adhesive removal methods was capable to restore the enamel to its earlier morphology; a statistically significant increase in surface roughness parameters was reported with a high-speed 12 flute TC bur for Rq and Rt.

New aesthetic in-house 3D-printed brackets: proof of concept and fundamental mechanical properties

Objectives

Three-dimensional (3D) printing technology is an emerging manufacturing process for many orthodontic appliances, and the aim of this study was to evaluate the mechanical properties of resin-based materials as alternatives for the in-house preparation of orthodontic brackets.

Material and Methods

Two types of 3D printed resins used for temporary (T) and permanent (P) crown fabrication were included in this study. Ten blocks from each resin were manufactured by a 3D printer and, after embedding them in acrylic resin, the samples were subjected to metallographic grinding and polishing, followed by instrumented indentation testing (IIT). Martens hardness (HM), indentation modulus (E_IT), and elastic index (η_IT) were determined with a Vickers indenter recording force-indentation depth curves from each specimen. After calculating descriptive statistics, differences between material types were investigated with Wilcoxon rank sum test accounting for clustering of measurements within specimens at alpha = 5%.

Results

No statistically significant differences in the mechanical properties of the two tested materials were seen: HM: median 279 N/mm² (interquartile range [IQR] 275–287 N/mm²) for T and median 279 N/mm² (IQR 270–285 N/mm²) for P (P value = 0.63); E_IT: median 5548 MPa (IQR 5425–5834 MPa) for T and median 5644 (IQR 5420–5850 MPa) for P (P value = 0.84); η_IT: median 47.1% (46.0–47.7%) for T and median 46.0% (IQR 45.4–47.8%) for P (P value = 0.24).

Conclusions

Under the limitations of this study, it may be concluded that the mechanical properties of the two 3D printed resins tested are equal, and thus, no differences in their clinical performance are expected.

Hydroxyapatite Film Coating by Er:YAG Pulsed Laser Deposition Method for the Repair of Enamel Defects

There are treatments available for enamel demineralization or acid erosion, but they have limitations. We aimed to manufacture a device that could directly form a hydroxyapatite (HAp) film coating on the enamel with a chairside erbium-doped yttrium aluminum garnet (Er:YAG) laser using the pulsed laser deposition (PLD) method for repairing enamel defects. We used decalcified bovine enamel specimens and compacted α-tricalcium phosphate (α-TCP) as targets of Er:YAG-PLD. With irradiation, an α-TCP coating layer was immediately deposited on the specimen surface. The morphological, mechanical, and chemical characteristics of the coatings were evaluated using scanning electron microscopy (SEM), scanning probe microscopy (SPM), X-ray diffractometry (XRD), and a micro-Vickers hardness tester. Wear resistance, cell attachment of the HAp coatings, and temperature changes during the Er:YAG-PLD procedure were also observed. SEM demonstrated that the α-TCP powder turned into microparticles by irradiation. XRD peaks revealed that the coatings were almost hydrolyzed into HAp within 2 days. Micro-Vickers hardness indicated that the hardness lost by decalcification was almost recovered by the coatings. The results suggest that the Er:YAG-PLD technique is useful for repairing enamel defects and has great potential for future clinical applications.

CO2 laser irradiation for debonding ceramic orthodontic brackets

This study evaluated shear bond strength (SBS), adhesive remnant index (ARI) and fracture mode of chemically and mechanically retained ceramic brackets bonded with different composite resins and irradiated with CO2 laser. The null hypothesis was that ceramic brackets bonded with different composite resins and irradiated with CO2 laser would have similar SBS values. Ninety human premolars were divided into four experimental groups according to the combination of type of composite resin (Transbond XT and Z 250) and type of ceramic bracket (Fascination and Mystique), and two control groups (n=15). In the four experimental groups, the brackets were irradiated with CO2 laser at 10 W for 3 seconds before SBS testing. Enamel surface ARI was calculated after debonding under electron microscopy scanning. ANOVA and the Mann-Whitney test were used for statistical analysis. The laser groups had lower SBS values than the non-irradiated groups (control) (p<0.05). The mechanically retained brackets (Mystique) had the higher (p<0.05) and Z250 had the lower SBS values after CO2 laser irradiation. The groups bonded with Z250 had the highest ARI. Adhesive fractures were the most prevalent. The null hypothesis was rejected. CO2 laser decreased SBS efficiently and facilitated debonding of mechanically and chemically retained ceramic brackets.

Three-dimensional non-destructive visualization of teeth enamel microcracks using X-ray micro-computed tomography

Although the topic of tooth fractures has been extensively analyzed in the dental literature, there is still insufficient information about the potential effect of enamel microcracks (EMCs) on the underlying tooth structures. For a precise examination of the extent of the damage to the tooth structure in the area of EMCs, it is necessary to carry out their volumetric [(three-dimensional (3D)] evaluation. The aim of this study was to validate an X-ray micro-computed tomography ([Formula: see text]CT) as a technique suitable for 3D non-destructive visualization and qualitative analysis of teeth EMCs of different severity. Extracted human maxillary premolars were examined using a [Formula: see text]CT instrument ZEISS Xradia 520 Versa. In order to separate crack, dentin, and enamel volumes a Deep Learning (DL) algorithm, part of the Dragonfly's segmentation toolkit, was utilized. For segmentation needs we implemented Dragonfly's pre-built UNet neural network. The scanning technique which was used made it possible to recognize and detect not only EMCs that are visible on the outer surface but also those that are buried deep inside the tooth. The 3D visualization, combined with DL assisted segmentation, enabled the evaluation of the dynamics of an EMC and precise examination of its position with respect to the dentin-enamel junction.

Comparative evaluation of the efficacy of the desensitizing and remineralizing agent in the reduction of dentin hypersensitivity after orthodontic debonding - a randomized clinical trial

Introduction

Enamel loss is a common problem during various orthodontic procedures. The study aims to compare the efficacy of a desensitizer and remineralizer in the reduction of the dentin hypersensitivity (DH) associated with enamel microcracks after orthodontic debonding.

Methods

A unicentric two arm parallel study with 30 subjects randomly assigned to each groups following debonding. Group-1 subjects were treated with Gluma® desensitizer (5% glutaraldehyde and 35% hydroxyethyl methacrylate (HEMA)) and the Group-2 intervention included a remineralizing agent GC Tooth Mousse Plus® (casein phospho peptide and amorphous calcium Fluro phosphate (CPP:ACFP)). The Visual Analogue Scale (VAS) was utilized to evaluate DH as subjective perception of pain following the Air blast test and Cold test. The VAS scale was indexed from 0–10 markings based on the intensity of perception. Five different time points T0 and T1 - immediately after debonding and intervention on day 1, T2 – 48 hours, and T3 after 72 hours were taken for the assessment of VAS scores.

Results

The VAS scores for the airblast test for group 1 were (2.73, 0, 0.06, 0.03) and group 2 (2.46, 0, 0.16, 0.13) at different periods. The sensitivity scores for the cold blast test for group 1 were (2.73, 0, 0.13, 0.03) and for group 2 (2.46, 0, 0.16, 0.13). There was 98 percent reduction in DH between T0 and T3 and was statistically significant (p<0.05) for both the groups.

Conclusion

Gluma® desensitizer and GC Tooth Mousse Plus® are equally effective in the reduction of DH in the orthodontic patient following debonding.

In vivo examination of enamel microcracks after orthodontic debonding: Is there a need for detailed analysis?

INTRODUCTION

Our aim was to assess changes in the number of enamel microcracks (EMCs) after removing metal brackets in teeth with and without visible EMCs before the bonding procedure.

METHODS

Before bonding, 13 patients having teeth with visible EMCs and 13 subjects whose teeth were free of EMCs were included in the study. All patients were asked to complete a questionnaire with a detailed medical history at the beginning of treatment and after removing metal brackets. The number of teeth with visible EMCs and the number of premolars without EMCs were recorded for each subject twice, that is, before bonding and after debonding, together with the tooth sensitivity assessments elicited by compressed air and cold testing.

RESULTS

The number of visible EMCs in premolars increased after removing metal brackets. EMCs were recorded in at least 25.0% of all evaluated teeth for the patients having teeth with and without visible EMCs at the beginning of treatment. However, the changes in the number of visible EMCs were not significantly different (P = 0.619) between the groups. For the subjects with visible EMCs, tooth sensitivity caused by cold was registered nearly 3 times more often after removing brackets compared with the patients without EMCs prior bonding.

CONCLUSIONS

Formation of EMCs was noticed after debonding. Changes in the number appeared to be similar for the subjects with and without visible EMCs before bonding. Higher incidence of EMCs was associated with more frequent tooth sensitivity perceptions after removing brackets.

The use of the laser confocal scanning microscopy to measure resin remnants on customized lingual bracket

Background

The study aimed to evaluate the permanence of resin and enamel remains on lingual brackets at the end of orthodontic treatment and after the debonding procedure. The evaluation of resin remnants on customized lingual brackets bases has never done before in other studies because they are curved, and traditional techniques are not applicable.

Methods

The sample consisted of 100 lingual brackets (25 incisors, 25 canines, 25 premolars, 25 molars) scanned with a confocal laser microscope (OLS4000). We measured the brackets' surface and the area of resin remnants with the software of the microscope. Median and quartiles were presented to describe the data. ARI calculation was indirect for each tooth, measuring the resin remnants to the total surface of the bracket. The Kruskal-Wallis test and Fisher test were applied respectively to compare the percentages of remnants and the frequencies of the ARI between the four groups.

Results

After the analyses, 13 brackets had no adhesive remnants (ARI 0), 29 brackets had less than 50% of resin remnants (ARI 1), 50 brackets had more than 50% of resin remnants (ARI 2), and 8 brackets had 100% of adhesive (ARI 3). Canines brackets presented the lower amount of resin followed by premolars, incisors, and molars.

Conclusion

Lingual brackets showed a high frequency of ARI = 2. The median percentage of the bracket surface covered by resin was 41%. We observed a slight tendency of more resin remnants on molar brackets, due to half-pad configuration. The authors suggest paying attention during the debonding procedure of molar brackets since a stronger connection between the adhesive and the bracket mesh means a higher risk of enamel damage.

A Novel Method Using Confocal Laser Scanning Microscopy for Three-Dimensional Analysis of Human Dental Enamel Subjected to Ceramic Bracket Debonding

The aim of this in vitro study was to present a method using confocal laser scanning microscopy for three-dimensional analysis of human dental enamel subjected to ceramic bracket debonding. The labial enamel surfaces of three upper central incisors were prepared and mounted in the form of standardized specimens. A sample repositioning protocol was established to enable surface measurement and analysis before and after bracket debonding. Observations were made of representative areas measuring 1,280 × 1,280 μm2, in the center of the enamel samples, as well as of the total topography (2,500 × 3,500 μm) of the bonding areas provided by the equipment software. Noncontact three-dimensional high-resolution image analyses revealed the capabilities of the employed technique and methodology to permit the examination of specific characteristics and alterations on the surfaces, before and after the debonding and finishing procedures. The new protocol was effective to provide qualitative and quantitative assessments of changes on the same dental surfaces at different trial times. The methodology constitutes a feasible tool for revealing the effects of debonding of ceramic brackets on sound and previously injured dental enamel surfaces.

Debonding and Clean-Up in Orthodontics: Evaluation of Different Techniques and Micro-Morphological Aspects of the Enamel Surface

There is currently no consensus on the best way to remove adhesive remnants from teeth following debonding. The main objective of this study is to evaluate and compare the effectiveness of four adhesive resin removal (clean-up) techniques, performed with or without the use of an operative microscope. Forty human teeth were duplicated using an epoxy resin for impregnation. Brackets were bonded to teeth and debonded from teeth. Then, the samples were randomly divided into two equal groups-the naked eye group and the magnification group-and further subdivided into four equal subgroups, in order to compare the different techniques used for the clean-up. Each subgroup was formed of five natural teeth with the respective pre- and post-bonding replicas. Macro- and micro-analysis by means of a stereomicroscope and scanning electron microscopy evaluated, qualitatively and quantitatively, the adhesive remnant index and the damage index of the enamel. Overall, the magnification improved the removal of resins compared to the naked eye (p < 0.001), and the use of magnification constantly reduced resin residual and surface damage. Enamel damage and adhesive residual from the clean-up procedures represent an ascertained risk in orthodontics. The use of a magnification system improves the quality of debonding and clean-up techniques in a significant way.

Novel Digital Technique to Quantify the Area and Volume of Cement Remaining and Enamel Removed after Fixed Multibracket Appliance Therapy Debonding: An In Vitro Study

The aim of this study was to construct a novel, repeatable, reproducible, and accurate measurement protocol for the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere fixed multibracket appliances. A total of 30 brackets were cemented and removed with over 30 extracted teeth embedded into three experimental models of epoxy resin. The models were scanned before and after bracket placement, bracket debonding, and polishing the remaining cement. The brackets were submitted to micro-computed tomography. The standard tessellation language digital files were aligned, segmented, and re-aligned using geomorphometric software. The digital measurement technique accuracy, repeatability, and reproducibility were analyzed using Gage R&R statistical analysis. The variability attributable to the area and volume measurement techniques of the total variability of the samples was 0.70% and 0.11% for repeatability, respectively, and 0.79% and 0.01% for reproducibility, respectively. The re-alignment procedure is a repeatable, reproducible, and accurate technique that can be used to measure the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere the fixed multibracket appliance.

Priming and bonding metal, ceramic and polycarbonate brackets

Objective: To investigate if primers can be used to modify bonding characteristics of orthodontic brackets.

Materials and methods: Stainless steel, zirconia-alumina ceramic and polycarbonate brackets were bonded to enamel with and without universal and bracket material specific primers on the bracket base. Orthodontic adhesive cement (Transbond™XT) was used for bonding. The primers in each group (n = 10) were silane based (RelyX™ Ceramic Primer) and universal primer (Monobond Plus) for ceramic and metal brackets, and adhesive resin (Adper™ Scotchbond™ Multi-Purpose Adhesive) and composite primer (GC Composite Primer) for polycarbonate brackets. Controls with no primer were used for all bracket types. Teeth with bonded brackets were stored in distilled water in 37 °C for 7 days and debonded with static shear loading. Debonding forces were recorded and analyzed with ANOVA. Adhesive remnant index (ARI) was determined and enamel damage examined.

Results: The bond strength without primers was 8.14 MPa (±1.49) for metal, 21.9 MPa (±3.55) for ceramic and 10.47 MPa (±2.11) for polycarbonate brackets (p < .05). Using silane as primer increased the bond strength of ceramic brackets significantly to 26.45 MPa (±5.00) (p < .05). ARI-scores were mostly 2–3 (>50% of the adhesive left on the enamel after debonding), except with silane and ceramic brackets, ARI-score was mostly 0–1 (>50% of the adhesive left on the bracket). Debonding caused fractured enamel in four specimens with ceramic brackets.

Conclusions: Bond strength was highest for ceramic brackets. Silane primer increased bond strength when used with ceramic brackets leading to enamel fractures, but otherwise primers had only minor effect on the bond strength values.

Impact of Fluorosis on the Tensile Bond Strength of Metal Brackets and the Prevalence of Enamel Microcracks

The objective of this in vitro study was to determine the effects of dental fluorosis on the tensile bond strength of metal brackets bonded to human teeth and to evaluate the changes in the tooth enamel surface after debonding. The study sample consisted of 68 recently extracted human upper premolars, which were divided into 2 groups: the fluorosis group (34 fluorosed teeth) and the control group (34 healthy teeth). Identical premolar metal brackets were bonded on the buccal surfaces of the teeth. Both groups were submitted to a tension test using a universal testing machine. The number and length of the enamel microcracks in the buccal surface of each tooth were determined before bracket bonding and after debonding using a stereomicroscope. The percentage adhesive remnant index (PARI) was calculated after debonding. The results showed that the tensile bond strength (TBS) of brackets bonded to fluorosed teeth was 21.08% lower than that of brackets bonded to healthy teeth (p < 0.0001). The length of the enamel microcracks on fluorosed teeth increased by 47.4% after debonding, whereas the control group showed an increase of only 12.6%. The PARI showed lower values for fluorosed teeth in comparison to the control group (p = 0.047). In conclusion, dental fluorosis has a negative impact on tensile bond strength and the length of microcracks formed after bracket debonding.

Enamel microcracks in the form of tooth damage during orthodontic debonding: a systematic review and meta-analysis of in vitro studies

Objectives

To evaluate and compare the enamel microcracks (EMCs) characteristics (qualitative and quantitative) in the form of tooth damage before and after debonding from human teeth of in vitro studies.

Eligibility criteria

Laboratorial studies evaluating EMCs characteristics before and after debonding metal and ceramic brackets from human teeth with intact buccal enamel.

Information sources

An electronic search of four databases (all databases of the Cochrane Library, CA Web of Science, MEDLINE via PubMed, and Google Scholar) and additional manual searches were carried out, without language restrictions. Studies published between 2000 and 2017 years were selected. Reference lists of the included articles were screened, and authors were contacted when necessary.

Risk of bias

The following six parameters were analyzed: blinding of examiner and outcome assessment, incomplete outcome data before bonding and after debonding, selective outcome reporting, and incomplete reporting of EMCs assessment.

Included studies

Out of 430 potentially eligible studies, 259 were screened by title and abstract, 180 were selected for full-text analysis, 14 were included in the systematic review. Seven studies were selected for the meta-analysis.

Synthesis of results

The results for EMCs characteristics were expressed as mean differences (MDs) with their 95 per cent confidence intervals (CIs), and calculated from random-effects meta-analyses. Debonding was associated with the increase in number (three studies, MD = 3.50, 95% CI, 2.13 to 4.87, P < 0.00001), length (seven studies, MD = 3.09 mm, 95% CI, 0.75-5.43, P < 0.00001), and width (three studies, MD = 0.39 µm, 95% CI, -0.01 to 0.79, P = 0.06) of EMCs. Considerable statistical heterogeneity was found for two forest plots evaluating the changes of number and length characteristics during debonding.

Conclusions

There is weak evidence indicating length and width of EMCs increase following bracket removal and the scientific evidence concerning quantitative evaluation of the number parameter before and after debonding is insufficient. However, there is a strong evidence that after debonding the number of EMCs is likely to increase.

Registration

No registration was performed.

Clinical performance of uncoated and precoated polymer mesh base ceramic brackets

Background

To evaluate the clinical performance of the two types of InVu ceramic brackets. The clinical performance of these brackets was measured by determining failure as well as survival rates and tie-wing fractures. Enamel surface evaluation following bracket and remnant removal was performed.

Subjects and methods

Forty non-extraction patients (31 females, 9 males) with a mean chronological age of 16 years 4 months composed this study. Bonding was performed with a split-mouth design using operator-coated and Readi-Base eXact InVu brackets. During the treatment period (45.89 ± 2.0 weeks), the failed brackets were recorded as well as the brackets with tie-wing fractures. Debracketing was undertaken with a ligature cutter (delamination technique) as recommended by the manufacturer. A modified remnant index (MRI) was used to visually evaluate the amount of remnants remaining on the tooth surface. Horizontal crack evaluation was carried out via transillumination.

Results

Operator-coated InVu brackets demonstrated a bond failure rate of 2.6%. This value was 6.8% for the Readi-Base eXact InVu brackets. Failure rates as well as survival rates presented a statistically significant difference (P = 0.006). A higher bond failure for the premolar teeth when compared to incisor teeth, as well as a higher bond failure in the lower arch when compared to the upper arch was found. These findings were statistically significant (P = 0.000 and P = 0.007, respectively). The effect of gender on bond failure rate (P = 0.508) and survival rate (P = 0.503) was not statistically significant. Both bracket types showed comparable results for tie-wing fractures (P = 0.174). A statistically significant difference was obtained for the MRI scores (P = 0.000). No horizontal enamel cracks were observed for both bracket types.

Conclusion

The operator-coated InVu brackets demonstrated a lower failure rate when compared to the Readi-Base eXact pre-applied adhesive InVu brackets. The debonding procedure was safe for both bracket types.

Shear bond strength and bonding properties of orthodontic and nano adhesives: A comparative In-Vitro study

Introduction:

Nano restorative composites have been successfully used in restorative dentistry and have high strength and wear resistance. Conventional orthodontic adhesives also possess optimal strength to withstand occlusal forces. This study was done to compare the shear bond strength (SBS) of orthodontic bracket after bonding with nanorestorative composite and orthodontic adhesives.

Materials and Methods:

This in-vitro experimental study used sixty extracted teeth (divided into two groups). In Group A (n = 30), the brackets were bonded with Filtek Z350 (3M/Unitek, Monrovia, California, USA), a nano ceramic restorative composite, and in Group B (n = 30), the brackets were bonded with Transbond XT (3M/Unitek, Monrovia, California, USA), a conventional orthodontic adhesive. The SBS of the orthodontic brackets was measured using a universal testing machine. The modified 0–5-scale adhesive remnant index (ARI) was used to assess the amount of adhesive on enamel and bracket surfaces. The surface topography was observed to evaluate enamel damage.

Results:

The mean (standard deviation [SD]) SBS of 11.07 (1.96) Mega Pascal (MPa) was observed with Filtek Z350, whereas the group bonded with Transbond XT showed the mean (SD) SBS of 12.18 (1.69) MPa. The results showed that Transbond light curing adhesive produced higher SBS than Filtek, but the difference was statistically insignificant (P = 0.088). The comparison of ARI score between the two groups also showed statistically insignificant difference (χ² = 4.764, df = 5, P = 0.445), and most of the teeth in both groups exhibited score 3 (63%), showing the least damaging mode of bond failure to the enamel bracket interface.

Conclusion:

There was no significant difference in the mean SBS of Filtek Z and Transbond XT adhesives. Both materials showed optimum bond strength to withstand occlusal forces.

Variations in enamel damage after debonding of two different bracket base designs: An in vitro study

Background. Bracket base design is a factor influencing shear bond strength. High shear bond strength leads to enamel crack formation during debonding. The aim of this study was to compare enamel damage variations, including the number and length of enamel cracks after debonding of two different base designs. Methods. Eighty-eight extracted human premolars were randomly divided into2 groups (n=44). The teeth in each group were bonded by two types of brackets with different base designs: 80-gauge mesh design versus anchor pylon design with pylons for adhesive retention. The number and length of enamel cracks before bonding and after debonding were evaluated under an optical stereomicroscope ×40 in both groups. Mann-Whitney U test was used to compare the number of cracks between the two groups. ANCOVA was used for comparison of crack lengths after and before debonding in each group and between the two groups. Results. There was a significant increase in enamel crack length and numbers in each group after debonding. There was no significant difference in enamel crack numbers after debonding between the two groups, whereas the length of enamel cracks was significantly greater in anchor pylon base design after debonding. Conclusion. Bracket bases with pylon design for adhesive retention caused more iatrogenic debonding damage to enamel surface.

Enamel defects during orthodontic treatment

Background/Aim: Orthodontic treatment has an inherent potential for causing defects to enamel in the course of bonding and debonding procedures, interproximal enamel stripping and induce the presence of white spot lesions, enamel discoloration or wear. The aim of this study is to present the stages of orthodontic therapy associated with potential damage to enamel and list the enamel alterations observed in each stage. Material and Methods: A literature search was carried out in MEDLINEPubMed database for papers published up to and including February 2015. Results: Enamel loss is induced by cleaning with abrasives before etching, the acid etching process itself, forcibly removing brackets, and mechanical removal of composite remnants with rotary instruments. Loss of enamel or topographic changes in the form of cracks, scarring and scratches may occur. Clinicians may cause structural damage of enamel by interproximal enamel stripping. Additionally, the enamel surface may become demineralized due to plaque accumulation around the orthodontic attachments. Additional complications are enamel color alterations due to its microstructural modifications or discoloration of adhesive remnants and enamel wear due to contact with the brackets of the opposing teeth. Conclusions: Therapeutic procedures performed in the course of orthodontic treatment may cause irreversible physical damage to the outermost enamel. To avoid this, the orthodontic practitioner should take great care in every stage of the treatment and manage the enamel surface conservatively. Moreover, patients should follow an effective oral hygiene regimen. Given these conditions enamel damage during orthodontic therapy is eliminated and longevity of the dentition is promoted.

Does orthodontic debonding lead to tooth sensitivity? Comparison of teeth with and without visible enamel microcracks

INTRODUCTION

Our aim was to assess the possible changes in sensitivity of teeth with and without visible enamel microcracks (EMCs) up to 1 week after the removal of metal brackets.

METHODS

After debonding, 15 patients possessing teeth with visible EMCs and 15 subjects whose teeth were free of EMCs were enrolled in the study. For each experimental group, a control group was formed. The assessments of tooth sensitivity elicited by compressed air and cold testing were performed 5 times: just before debonding, immediately after debonding, and at 1, 3, and 7 days after debonding. Tooth sensitivity was recorded on a 100-mm visual analog scale.

RESULTS

For the patients without visible EMCs, discomfort peaked immediately after debonding and started to decrease on day 1; at 1 week after debonding, the visual analog scale scores were lower than just before debonding and immediately after debonding. For the subjects possessing teeth with visible EMCs, the pattern of sensitivity dynamic was inherently the same. However, the patients with visible EMCs showed higher visual analog scale values at each time interval.

CONCLUSIONS

Debonding leads to a short-term increase in tooth sensitivity. EMCs, a form of enamel damage, do not predispose to greater sensitivity perception in relation to bracket removal.

[Ultrastructural changes of human dental hard tissues during orthodontic treatment with fixed appliances]

The aim of the study was to evaluate ultrastructural changes of dental enamel after fixation of orthodontic appliances, initial influence of orthodontic forces and removal of braces. Five intact permanent tooth extracted for orthodontic reasons were included in the experimental study. Scanning probe microscopy was conducted in 4 random enamel points in each tooth (20 points overall) in semi-contact mode with standard 10 nm probes. The study showed ultrastructural enamel changes such as nanofractures up to 1 mm along the braces locks. The changes correlated with surface morphological features and teeth anatomy and may play an important role in dental decay and non-carious lesions occurring in the course of orthodontic treatment.

Evaluation of Enamel Surface Roughness after Various Finishing Techniques for Debonding of Orthodontic Brackets

Objective

The aim of this study was to evaluate the surface roughness of enamel after debonding with various types of burs.

Methods

The buccal surfaces of 20 mandibular incisors for each group of bur were subjected to profilometer analysis, and three parameters of surface irregularity were recorded. After bracket debonding, adhesive remnants were removed by tungsten carbide burs in low-speed, high-speed, and stainbuster settings. The samples were evaluated at pre-treatment (on sound enamel) (T1) and post-treatment (T2) by a profilometer. The specimens were measured twice, and the mean values were recorded.

Results

The results were analyzed in intra-group comparisons with paired t-tests and in inter-group comparisons with one-way ANOVA and Tukey's HSD test. All resin removal techniques significantly increased enamel surface roughness (p<0.05). According to one-way ANOVA, there were significant differences in the effect of enamel surface roughness between all methods (p<0.05). The high-speed bur caused the maximum roughness values and the stainbuster bur caused the minimum roughness values in all the parameters (Ra, Rz, and Rq).

Conclusion

The three types of burs used for finishing methods revealed significant differences in the enamel surface after debonding. However, the stainbuster bur created smoother surfaces than the other applied methods.

SEM-Evaluation of enamel surfaces after orthodontic debonding: a 6 and 12-month follow-up in vivo study

The purpose of this in vivo study was to compare the morphology of the enamel surfaces before bracket bonding and 6 and 12 months after debonding. Replicas of thirty-two maxillary second premolars of 16 volunteers were made before bracket bonding (T0), after debonding (T1), 6 months (T2), and 12 months (T3) later. Scanning electron microscope (SEM) images of the labial enamel surfaces were taken at T0, T1, T2, and T3 at increasing magnifications and analyzed according to the enamel damage index EDI. Data evaluation by using Friedman test followed by Wilcoxon signed ranks test with Bonferroni adjustment did not reveal statistically significant differences in the mean EDI at T0, T2, and T3, whereas the mean EDI at T1 was significantly higher than at T0, T2, and T3 (p < 0.05). The debonding procedure tested in this study produces no clinically relevant enamel damage. These alterations are reversible indeed, as a progressive restoration to pretreatment condition is evident after 6 months already and even more after 12 months.

The prognostic value of visually assessing enamel microcracks: Do debonding and adhesive removal contribute to their increase?

OBJECTIVE

To find a correlation between the severity of enamel microcracks (EMCs) and their increase during debonding and residual adhesive removal (RAR).

MATERIALS AND METHODS

Following their examination with scanning electron microscopy (SEM), 90 extracted human premolars were divided into three groups of 30: group 1, teeth having pronounced EMCs (visible with the naked eye under normal room illumination); group 2, teeth showing weak EMCs (not apparent under normal room illumination but visible by SEM); and group 3, a control group. EMCs have been classified into weak and pronounced, based on their visibility. Metal brackets (MB) and ceramic brackets (CB), 15 of each type, were bonded to all the teeth from groups 1 and 2. Debonding was performed with pliers, followed by RAR. The location, length, and width of the longest EMCs were measured using SEM before and after debonding.

RESULTS

The mean overall width (Woverall) was higher for pronounced EMCs before and after debonding CB (P < .05), and after the removal of MB. Pronounced EMCs showed greater length values using both types of brackets. After debonding, the increase in Woverall of pronounced EMCs was 0.57 µm with MB (P < .05) and 0.30 µm with CB; for weak EMCs, - 0.32 µm with MB and 0.30 µm with CB.

CONCLUSIONS

Although the teeth having pronounced EMCs showed higher width and length values, this did not predispose to greater EMCs increase after debonding MB and CB followed by RAR.

Effects of Diode Laser Debonding of Ceramic Brackets on Enamel Surface and Pulpal Temperature

AIM

Debonding of ceramic brackets due to their high bond strength and low fracture toughness is one of the most challenging complications of orthodontic clinicians. Application of lasers might be effective in the debonding of ceramic brackets as they reduce bond strength of resins and, therefore, can eliminate the risk of enamel damage. However, the thermal effects of laser radiation on dental tissue can cause undesirable results. The aim of this study is to evaluate the enamel surface characteristics and pulpal temperature changes of teeth after debonding of ceramic brackets with or without laser light.

MATERIALS AND METHODS

Thirty polycrystalline brackets were bonded to 30 intact extracted premolars, and later debonded conventionally or through a diode laser (2.5 W, 980 nm). The laser was applied for 10 seconds with sweeping movement. After debonding, the adhesive remnant index (ARI), the lengths and frequency of enamel cracks were compared among the groups. The increase in intrapulpal temperature was also measured. The collected data were analyzed by Chi-squared test and paired t-test using Statistical Package for Social Sciences (SPSS) software.

RESULTS

There was no case of enamel fracture in none of the groups. Laser debonding caused a significant decrease in the frequency and lengths of enamel cracks, compared to conventional debonding. In laser debonding group, the increase in intrapulpal temperature (1.46°C) was significantly below the benchmark of 5.5°C for all the specimens. No significant difference was observed in ARI scores among the groups.

CONCLUSION

Laser-assisted debonding of ceramic brackets could reduce the risk of enamel damage, without causing thermal damage to the pulp. However, some increases in the length and frequency of enamel cracks should be expected with all debonding methods.

Effect of adhesive resin flexibility on enamel fracture during metal bracket debonding: an ex vivo study

OBJECTIVE

To test the null hypothesis that neither the flexural properties of orthodontic adhesive resins nor the enamel pre-treatment methods would affect metal bracket debonding behaviours, including enamel fracture.

MATERIALS AND METHODS

A dimethacrylate-based resin (Transbond XT, TX) and two methyl methacrylate (MMA)-based resins (Super-Bond C&B, SB; an experimental light-cured resin, EXP) were tested. Flexural strength and flexural modulus for each resin were measured by a three-point-bending test. Metal brackets were bonded to human enamel pretreated with total-etch (TE) or self-etch adhesive using one of the three resins (a total of six groups, n = 15). After 24 hours of storage in water at 37°C, a shear bond strength (SBS) test was performed using the wire loop method. After debonding, remaining resin on the enamel surfaces and occurrence of enamel fracture were assessed. Statistical significance was set at P < 0.05.

RESULTS

The two MMA resins exhibited substantially lower flexural strength and modulus values than the TX resin. The mean SBS values of all groups (10.15-11.09MPa) were statistically equivalent to one another (P > 0.05), except for the TE-TX group (13.51MPa, P < 0.05). The two EXP groups showed less resin remnant. Only in the two TX groups were enamel fractures observed (three cases for each group).

LIMITATIONS

The results were drawn only from ex vivo experiments.

CONCLUSIONS

The hypothesis is rejected. This study suggests that a more flexible MMA resin is favourable for avoiding enamel fracture during metal bracket debonding.

Effects of surface treatment and artificial aging on the shear bond strength of orthodontic brackets bonded to four different provisional restorations

OBJECTIVE

To evaluate the combined effects of material type, surface treatment, and thermocycling on the bond strength of orthodontic brackets to materials used for the fabrication of provisional crowns.

MATERIALS AND METHODS

Four materials were included in this study (ProTemp, Trim Plus, Trim II, and Superpont C+B). Sixty cylindrical specimens (1 × 3 cm) were prepared from each material and equally divided into three groups. The first group was ground with silica carbide paper, the second was polished with pumice, and the last group was sandblasted with 50-µm aluminum oxide particles. Stainless-steel maxillary central incisor brackets (Victory Series, 3M) were bonded to the provisional material specimens with Transbond XT light-cured composite resin, and half of the specimens from each group were thermocycled 500 times in 5°C and 55°C water baths. Then the brackets were debonded with shear testing, and the results were statistically analyzed by three-way analysis of variance and Tukey's multiple-comparison tests at α  =  0.05. Adhesive Remnant Index (ARI) was also identified.

RESULTS

Before and after thermocycling, ProTemp materials showed the highest shear bond strength with orthodontic brackets (10.3 and 13.1 MPa, respectively). The statistical analysis indicated an interaction among the three independent variables (P < .05) and statistically significant differences in bond strength among provisional materials (P < .001), surface treatments (P < .001), and thermocycling (P < .05). According to the ARI, most groups demonstrated adhesive failure.

CONCLUSIONS

The provisional material type, surface treatment, and artificial aging have a significant effect on bond strength. Sandblasting treatment exerts a beneficial effect on shear bond strength.

Bracket base remnants after orthodontic debonding

OBJECTIVE

To evaluate whether the debonding procedure leads to restitutio ad integrum of the enamel surface by investigating the presence of enamel within the bracket base remnants after debonding.

MATERIALS AND METHODS

Sixty patients who completed orthodontic treatment with fixed appliances were included. A total of 1068 brackets were microphotographed; the brackets presenting some remnants on the base (n = 818) were selected and analyzed with ImageJ software to measure the remnant area. From this population a statistically significant sample (n = 100) was observed under a scanning electron microscope to check for the presence of enamel within the remnants. Energy dispersive x-ray spectrometry was also performed to obtain quantitative data.

RESULTS

Statistically significant differences in the remnant percentage between arches were observed for incisor and canine brackets (P < .0001 and P = .022, respectively). From a morphologic analysis of the scanning electron micrographs the bracket bases were categorized in 3 groups: group A, bases presenting a thin enamel coat (83%); group B, bases showing sizable enamel fragments (7%); group C, bases with no morphologic evidence of enamel presence (10%). Calcium presence was noted on all evaluated brackets under energy dispersive x-ray spectrometry. No significant difference was observed in the Ca/Si ratio between group A (16.21%) and group B (18.77%), whereas the Ca/Si ratio in group C (5.40%) was significantly lower than that of the other groups (P < .323 and P = .0001, respectively).

CONCLUSION

The objective of an atraumatic debonding is not achieved yet; in some cases the damage could be clinically relevant.

Comparison between two methods for resin removing after bracket debonding

OBJECTIVE: The aim of this study was to assess - using scanning electron microscopy (SEM) - the effectiveness of two abrasive discs, one made from silicon and one from aluminum oxide, in removing adhesive remnants (AR) after debonding orthodontic brackets. METHODS: Ten randomly selected bovine teeth were used, i.e., 2 in the control group, and the other 8 divided into two groups, which had orthodontic brackets bonded to their surface with Concise Orthodontic Adhesive (3M). The following methods were employed - in one single step - to remove AR after debracketing: Group A, Optimize discs (TDV) and Group B, Onegloss discs (Shofu), used at low speed. After removing the AR with the aforementioned methods, the teeth were prepared to undergo SEM analysis, and photographs were taken of the enamel surface with 50x magnification. Six examiners evaluated the photographs applying the Zachrisson and Årtun enamel surface index (ESI) system (1979). RESULTS: Group A exhibited minor scratches on the enamel surface as well as some AR in some of the photographs, while Group B showed a smoother surface, little or no AR and some abrasion marks in the photographs. No statistically significant differences were found between the two methods and the control group. CONCLUSIONS: The two abrasive discs were effective in removing the AR after bracket debonding in one single step.

Does ultra-pulse CO(2) laser reduce the risk of enamel damage during debonding of ceramic brackets?

This study seeks to evaluate the enamel surface characteristics of teeth after debonding of ceramic brackets with or without laser light. Eighty premolars were bonded with either of the chemically retained or the mechanically retained ceramic brackets and later debonded conventionally or through a CO(2) laser (188 W, 400 Hz). The laser was applied for 5 s with scanning movement. After debonding, the adhesive remnant index (ARI), the incidence of bracket and enamel fracture, and the lengths, frequency, and directions of enamel cracks were compared among the groups. The increase in intrapulpal temperature was measured in ten extra specimens. The data were analyzed with SPSS software. There was one case of enamel fracture in the chemical retention/conventional debonding group. When brackets were removed with pliers, incidences of bracket fracture were 45% for the chemical retention, and 15% for the mechanical retention brackets. No case of enamel or bracket fracture was seen in the laser-debonded teeth. A significant difference was observed in ARI scores among the groups. Laser debonding caused a significant decrease in the frequency of enamel cracks, compared to conventional debonding. The increase in intrapulpal temperatures was below the benchmark of 5.5 °C for all the specimens. Laser-assisted debonding of ceramic brackets could reduce the risk of enamel damage and bracket fracture, and produce the more desirable ARI scores without causing thermal damage to the pulp. However, some augmentations in the length and frequency of enamel cracks should be expected with all debonding methods.

Evaluation of enamel surfaces after bracket debonding: an in-vivo study with scanning electron microscopy

INTRODUCTION

The purposes of this in-vivo study were to compare the modes of failure of uncoated and adhesive precoated metal brackets by using the adhesive remnant index, and to assess the quality of the enamel surface after cleanup by using the enamel damage index.

METHODS

Twelve Victory brackets (group A) and 12 Victory adhesive precoated brackets (group B) (both, 3M Unitek, Monrovia, Calif) were bonded onto the maxillary second premolars of 12 volunteers. The uncoated brackets were bonded with Transbond XT adhesive resin (3M Unitek). Replicas of the teeth were made before bonding (T0), after bracket removal (T1), and after cleanup (T2). Scanning electron microscope images of all labial enamel surfaces were taken at T0, T1, and T2, and these were evaluated according to the adhesive remnant index and the enamel damage index.

RESULTS

Evaluation of the adhesive remnant index scores with the chi-square test showed no statistically significant difference between the groups. Evaluation of the enamel damage index grades with the sign test for paired samples showed a statistically significant difference (P <0.01) between T0 and T2.

CONCLUSIONS

Uncoated and precoated brackets exhibited similar debonding patterns. Additionally, the debonding method tested in this study did not restore the original enamel surface, although there was no clinically relevant enamel damage.

In-vitro study of the effect of casein phosphopeptide amorphous calcium fluoride phosphate on iatrogenic damage to enamel during orthodontic adhesive removal

INTRODUCTION

White-spot lesions (WSL) might be susceptible to mechanical damage during orthodontic bracket and adhesive removal. The aims of this in-vitro study were to investigate enamel loss on bracket and adhesive removal when the brackets were surrounded by WSL and to determine the effect of remineralizing these lesions with a 1% (w/v) casein phosphopeptide amorphous calcium fluoride phosphate (CPP-ACFP) solution before bracket and adhesive removal.

METHODS

Precoated metal mandibular incisor brackets were centrally bonded onto polished third molars and WSL produced by exposure to a demineralization buffer for 4, 12, and 30 days (n = 20 per group). Half of the demineralized window was covered with acid-resistant nail varnish, and the specimens were then subjected to remineralization with 1% CPP-ACFP. Brackets and residual adhesive were removed, and enamel damage was assessed by digital photography, profilometry, and scanning electron microscopy. Lesion depth, mineral loss, and remineralization were measured by transverse microradiography.

RESULTS

WSL enamel around the bracket was more susceptible to iatrogenic damage at adhesive removal compared with sound enamel. Remineralization of lesions with 1% CPP-ACFP before adhesive removal significantly (P <0.002) reduced the area and depth of damage.

CONCLUSIONS

Remineralizing WSLs with CPP-ACFP before adhesive removal reduced iatrogenic enamel damage.