Significant Differences In Adhesive Remnant Index Scores Research Articles

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.

Introducing and assessing the efficacy of a novel method to reduce enamel damage after orthodontic bracket removal using two herbal-based resin colouring agents: An in vitro study

The differentiation of resin remnants from enamel is a critical factor to minimize enamel damage after bracket debonding. This study was conducted to produce, and ascertain the efficacy of two colouring agents in minimizing enamel loss, adhesive and bonding remnants, and surface roughness after debonding. Two dyes containing annatto (orange colour) and curcumin (yellow colour) were produced. Seventy-two maxillary premolars were divided into three groups. After bracket bonding and debonding, the adhesive remnant was removed with a fine diamond bur. In groups 1 and 2, the orange and yellow dyes were utilized during the removal process, respectively. In group 3 (control) adhesive was removed with no colouring agent. The buccolingual dimension of the teeth was measured at the occlusal, middle, and apical areas, before bonding and after clean-up. The adhesive remnant index (ARI) and bonding remnant index (BRI) scores were recorded and the surface roughness parameters were measured. Data were analysed by ANOVA, Tukey, and Fisher's exact tests (α=0.05). Enamel loss was significantly lower in the groups cleaned by the use of colouring agents than that of the control group (P<0.05). No bonding agent was observed when the dyes were used, whereas 65% of teeth in the control group showed the remaining bonding material (P<0.001). There was no significant difference in ARI scores or surface roughness alterations among the study groups (P>0.05). The two dyes produced in this study were effective in enhancing the visibility of residual resin materials and minimizing enamel loss during the clean-up process.

Effects of Surface Preparation with Sodium Hypochlorite on Shear Bond Strength and Residual Adhesive of Orthodontic Brackets on Primary and Permanent Teeth

Objective: To investigate the effects of surface preparation with sodium hypochlorite (NaOCl) on bracket shear bond strength and amount of residual adhesive on primary and permanent teeth. Materials and Methods: 24 permanent premolars, 12 in each group (groups I and III), and 24 primary molars, 12 in each group (groups II and IV) were included. In group I and II, 37% phosphoric acid was applied to the tooth surfaces, without using any other agent. In Group III and IV, 5.25% NaOCl was first applied. Following washing and drying, surface roughening was performed with phosphoric acid. The shear bond strengths (SBS) of the brackets bonded to the tooth surfaces was measured. After debonding, the base of each bracket was examined for adhesive remnant index (ARI) scores. Results: There were no statistically significant differences in SBS values between primary and permanent teeth with and without preparation with NaOCl(P&amp;gt;0.05). Mean SBS(18.55±14.98 MPa) was higher in permanent premolars subjected to surface deproteinization with NaOCl (group III) when compared with other groups, but the difference was not significant. There was no significant difference in ARI scores between the groups. Conclusions: The bond strength of orthodontic brackets or the distribution of ARI scores were similar between groups with and without NaOCl pretreatment. Hence, it can be concluded that conventional bonding procedures applied without any additional preparation to primary teeth are sufficient and the debonding of brackets didn’t cause any harm to enamel surfaces.

An In Vitro Study to Compare the Shear Bond Strength of Orthodontic Brackets Bonded to Permanent Teeth by Using Conventional Acid-Etching and Self-Etching Primers

Objectives: The objective of the present study was to evaluate and compare the bond strength of orthodontic brackets bonded to permanent teeth with a conventional acid-etching and self-etching primer systems. Also, the study aims to evaluate the mode of bond failure after debonding the brackets. Materials and Methods: It was an experimental study. Fifty extracted permanent premolars were collected, checked, and cleaned. Teeth were split equally into two groups, group A and B. Orthodontic brackets were bonded using conventional acid-etching and self-etching primer systems for group A and B, respectively. Shear bond strength (SBS) was measured with a universal testing machine, and the mode of bracket-adhesive failure was determined by using adhesive remnant index (ARI). Data were analyzed with a statistical software. Independent sample t-test was used to compare the SBS and Mann–Whitney U test was used to assess whether there is a significant difference of ARI score between the groups. Results: Although the SBS with self-etching primer was within clinically acceptable range, the overall mean SBS for group A (14.71 MPa) was significantly greater than group B (9.24 MPa) (P = 0.024). There was no significant difference in ARI scores between conventional acid-etching and self-etching groups (P = 0.801). Conclusion: The SBS of the conventional acid-etching was significantly higher than the self-etching primer. The SBS of self-etch was within the acceptable range to withstand the forces of mastication. The majority of the brackets recorded ARI score of 1 indicating a cohesive failure with no significant difference between acid-etch and self-etch groups.

Effect of the different debonding strength of metal and ceramic brackets on the degree of enamel microcrack healing.

ABSTRACTObjective: This study aims to determine shear debonding strength of metal and ceramic brackets, and the degree of enamel crack healing. Material and Methods: Extracted human maxillary premolars were flattened on the buccal surface, and randomly separated into five groups (n = 15). In control groups (groups 1 and 2), metal and ceramic brackets were bonded on flat polished enamel, while in experimental groups (groups 3 and 4), metal and ceramic brackets were bonded on the surface with boundary where corner cracks were created. Additionally, fifteen specimens (group 5) were also prepared for an indentation procedure with no bracket installation. The degree of crack healing was measured. All brackets were detached with a universal testing machine, and the adhesive remnant index (ARI) was also identified. Healing degree and apparent fracture toughness were then calculated. Results: Between groups with similar bracket types, there was no statistically significant difference in debonding strength. Regarding bracket types, ceramic brackets provided significantly higher debonding strength than metal brackets. There was a significant difference in ARI scores between metal and ceramic brackets. The corner cracks showed signs of healing in both horizontal and vertical directions. No statistically significant difference in the healing rates among the groups was found and the apparent fracture toughness increased from the initial to the final measurement. Conclusions: Within the limitations of this study, even though ceramic brackets required significantly higher debonding force compared to metal brackets, debonding stress was limited to the bonding site and did not affect the surrounding cracks on enamel.

The Performance of Universal Adhesives on Orthodontic Bracket Bonding

Abstract Objective This article aimed to assess the effects of double application of universal adhesives on the shear bond strength of orthodontic brackets. Materials and Method Seventy-five extracted human premolars were used. The teeth were randomly assigned into five groups based on the adhesive procedure (n = 15). The universal adhesives Scotchbond Universal (3M Oral Care) and Prime&amp;Bond Universal (Dentsply) were used (following manufacturer’s instructions and double application). Transbond XT Primer (3M Unitek) was employed as control. Following adhesive application, the brackets were bonded on the tooth surfaces. After storage in distilled water for 24 hours at 37°C, the specimens were subjugated to the shear bond strength test under a universal testing machine (Autograph AGS-X; Shimadzu). Data were analyzed with one-way analysis of variance and least significant difference tests (p = 0.05). The adhesive remnant index (ARI) was determined using a stereomicroscope (S4E; Leica Microsystems). Data of ARI scores were submitted to Pearson’s chi-square test. Results The highest shear bond strengths were acquired with Scotchbond Universal (p &lt; 0.05). The double application of Scotchbond Universal did not impact the shear bond strength. The lowest shear bond strength was found in Prime&amp;Bond Universal (p &lt; 0.05). The double application of Prime&amp;Bond Universal increased the shear bond strength (p &lt; 0.05). There were no significant differences in ARI scores among the groups (p &gt; 0.05). Conclusion The universal adhesives may be an alternative for the bonding of orthodontic brackets. The double application of universal adhesives might improve the shear bond strength of orthodontic brackets depending on the material.

Shear bond strength, adhesive remnant index, and anti-biofilm effects of a photoexcited modified orthodontic adhesive containing curcumin doped poly lactic-co-glycolic acid nanoparticles: An ex-vivo biofilm model of S. mutans on the enamel slab bonded brackets.

Potential complications during fixed orthodontic procedures are white spot lesions (WSLs) and tooth decay. This study evaluated the anti-biofilm activity of an orthodontic adhesive (OA) incorporating curcumin (Cur) doped Poly lactic-co-glycolic acid nanoparticles (Cur-PLGA-NPs), which can have the highest concentration of Cur-PLGA-NPs and shear bond strength (SBS) value simultaneously, against cariogenic bacteria i.e., Streptococcus mutans. Following synthesis and confirmation of Cur-PLGA-NPs, SBS and adhesive remnant index (ARI) of the modified orthodontic adhesives (MOA) containing Cur-PLGA-NPs (3, 5, 7, and 10 % wt.) were measured using universal testing machine and stereomicroscope, respectively. After artificial aging (continuously rinsed up to 180 days), the residual anti-biofilm ability of MOA which can have the highest concentration of Cur-PLGA-NPs and SBS value simultaneously were determined by anti-biofilm assay following photoexcited enamel slab bonded brackets by MOA containing Cur-PLGA-NPs against S. mutans biofilms using crystal violet assay. Adhesive with 7 % wt. Cur-PLGA-NPs revealed the highest concentration of Cur-PLGA-NPs and SBS value (16.19 ± 2.69 MPa, P < 0.05) simultaneously. No statistically significant difference in ARI scores was observed between the MOA and control (Transbond XT without the Cur-PLGA-NPs). On days 15, 30, 60, 90 and 120 there was a considerable decrease in optical density (OD) of preformed S. mutans biofilms on photoexcited enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs, to 94.1 %, 79.6 %, 69.6 %, 69.4 %, and, 55.1 % respectively in comparison to the control group (all, P < 0.05). From days 150 onwards, microbial biofilm formation was progressively increased on enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs compared to the control group (OA). Although chlorhexidine (2 %; as positive control) showed significant activity against pre-formed S. mutans biofilms on enamel slab bonded brackets using OA (99.1 % biofilm reduction; P = 0.001), its activity was slightly higher but not significant than photoexcited enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs on the days 15 and 30 (both, P > 0.05). The 7 % wt. Cur-PLGA-NPs can serve as an orthodontic adhesive antimicrobial additive as exposure to blue laser provides an acceptable antimicrobial effect against cariogenic bacteria for a considerable time.

Effect of Adhesion Boosters on the Shear Bond Strength of New Brackets Bonded to a Debonded Tooth Surface - An In vitro Study.

Context:Effect of adhesion boosters on shear bond strength of orthodontic brackets.Aim:The aim is to evaluate the shear bond strength and adhesive remnant index (ARI) score of new brackets bonded to a debonded tooth surface with and without the use of adhesion boosters.Settings and Designs:In vitro comparative study.Materials and Methods:Adhesion boosters: Enhance LC (Reliance, Itasca III) All Bond 2 (Bisco, Schaumsburg) and the Composite adhesives Transbond XT (3M UNITEK) Enlight (ORMCO) were used in this study. One hundred and eight extracted maxillary first premolar teeth were bonded with light cure composite to etched tooth surface. The brackets were then debonded with debonding pliers after 1 week and it was polished with low speed tungston carbide bur and rubber cup. The teeth were divided into six groups and they were etched, washed, and dried again. New brackets were rebonded to the tooth surface using composites with or without adhesion boosters. Then, the shear bond strength value was calculated for each bracket with a universal testing machine. ARI scores were also evaluated.Statistical Analysis Used:One-way ANOVA and least significant difference post hoc test was used for the association between variables. Probability value (P < 0.05) was considered statistically significant.Results:The results showed a statistically significant difference between the groups with a P < 0.001. There was no significant difference in ARI scores between the groups (P = 0.15).Conclusions:Both the adhesion boosters significantly improved the shear bond strength of orthodontic brackets. There was no statistically significant difference in the ARI scores.

Evaluation of the effect of different surface conditioning methods on shear bond strength of metal brackets bonded to aged composite restorations

There are controversies regarding the most reliable conditioning method of the aged composite surface to ensure optimum bond strength. The purpose of this study was to evaluate the shear bond strength of metal brackets to microhybrid composite restorations after different surface preparation techniques. A total of sixty microhybrid composite samples were prepared using upper right central incisor celluloid crown as a mold. Samples were treated with 4 different surface conditioning methods: (1) etching, (2) sandblasting, (3) grinding, and (4) CO2 laser irradiation. Samples were then bonded with metal brackets and underwent shear bond strength testing. A scanning electron microscope was carried out and the data was analysed by one-way ANOVA and post-hoc Tukey test. Bond failure was examined by stereomicroscope and scored based on adhesive remnant index (ARI). Kruskal-Wallis test was used to compare ARI values (α=0.05). Shear bond strength values in the sandblasting group (17.18±1.53MPa) were significantly higher than the other groups. There was no significant difference between the grinding (12.87±3.38MPa) and laser (11.08±1.37MPa) groups (P=0.09). The lowest values were recorded in the etching group (6.78±1.69MPa). There was a significant difference in ARI scores among the four groups (P<0.001). ARI scores were mostly 2 and 3 in the sandblasting and grinding group, while in the etching and laser groups ARI was mostly 0 and 1. Surface preparation by sandblasting and CO2 laser provides clinically acceptable results with regards to bond strength and ARI score, however grinding and acid etching failed to produce the same results.

Physico-mechanical and antimicrobial properties of an orthodontic adhesive containing cationic curcumin doped zinc oxide nanoparticles subjected to photodynamic therapy.

Potential complications on the crown level during fixed orthodontic procedures are white spot, enamel demineralization and tooth decay. This study evaluated the antimicrobial properties of an orthodontic adhesive incorporating cationic curcumin doped zinc oxide nanoparticles (cCur/ZnONPs), which can have the highest concentration of cCur/ZnONPs and shear bond strength (SBS) value simultaneously, against cariogenic bacteria including Streptococcus mutans, Streptococcus sobrinus, and Lactobacillus acidophilus. Following synthesis and confirmation of cCur/ZnONPs, SBS and adhesive remnant index (ARI) of the test adhesives containing cCur/ZnONPs (1.2, 2.5, 5, 7.5, and 10% wt.) were measured using universal testing machine and stereomicroscope, respectively. After continuously rinsed (up to 180 day), the residual antimicrobial ability of modified adhesives which can have the highest concentration of cCur/ZnONPs and SBS value simultaneously were determined by disc agar diffusion (DAD), biofilm formation inhibition, and metabolic activity assays following photo-activation using light-emitting diode (LED) for 5 min against multispecies cariogenic biofilm-producing bacteria. Adhesive with 7.5% wt. cCur/ZnONPs showed the highest concentration of cCur/ZnONPs and SBS value (14.89 ± 3.26 MPa, P < 0.05) simultaneously. No significant differences in ARI scores were found between the modified adhesive and control (Transbond XT without the cCur/ZnONPs). 7.5% wt. cCur/ZnONPs following photo-activation was not colonized by the test microorganisms and suppressed 100% metabolic activity of the test microorganisms up to 90 day compared to the control group (cCur/ZnONPs free LED irradiation; P < 0.05). In DAD assay, the reduction of photodynamic disinfection of the 7.5% wt. cCur/ZnONPs against test bacteria was positively associated to the time, in such a way that it was decreased significantly after 60 day. From days 120 onwards, microbial biofilm formation and metabolic activity was progressively increased on 7.5% wt. cCur/ZnONPs adhesive discs compared to the control group (cCur/ZnONPs free LED irradiation). Our findings highlight the photo-activated 7.5% wt. cCur/ZnONPs can serve as an orthodontic adhesive additive to control the cariogenic multispecies biofilm, and also to reduce their metabolic activity.

Comparison of shear bond strength of three different adhesives used as temporary bite raiser in daily orthodontic practice

The aim of this study was to evaluate the shear bond strength of three different adhesives (Transbond XT, Light Cure Adhesive, 3M Unitek; Transbond Plus, Light Cure Band Adhesive, 3M Unitek; Transbond Supreme LV, Low Viscosity Light Cure Adhesive, 3M Unitek), which were applied to the etched enamel of occlusal faces of mandibular molar teeth to gain bite opening. The null hypothesis was that there is no statistically significant difference between shear bond strength of these three adhesives. Forty-eight human molar teeth were equally divided into three groups (n=16). Teeth were embedded in self-curing acrylic resin and were polished and etched. Adhesives were applied on the teeth and all adhesives were light cured for 20seconds. Universal Testing Machine was used for shear bond strength tests with a crosshead blade loaded at a crosshead speed of 1mm/min. Evaluating the type of failure was done by using Adhesive Remnant Index (ARI) was used to evaluate the remaining adhesive on the tooth. One-way analysis of variance (ANOVA) was used to determine the significant differences between the three different orthodontic adhesives. There was no significant difference (P=0.774) between the groups according to ANOVA test. According to Kruskal-Wallis test there was no statistically significant differences in ARI scores among groups (P<0.01). The null hypothesis was accepted. There was no statistically significant difference among their bond strength values. All of three materials can be used as temporary bite openers.

The effect of an acidic food-simulating environment on the shear bond strength of self-ligating brackets with different base designs.

Aim. This study aims to evaluate the effect of acidic food simulant and (acetic acid 3%) on the shear bond strength (SBS) and adhesive remnant index (ARI) scores of one conventional and three different self-ligating brackets with different base designs. Materials and Methods. Freshly extracted first maxillary premolars (n = 160) were embedded in resin blocks. A conventional stainless steel bracket, Equilibrium 2, and three types of self-ligating brackets, Speed, In-Ovation R, and Damon 3MX, were bonded to teeth and exposed to distilled water (groups 1, 3, 5, and 7) or acetic acid 3% (groups 2, 4, 6, 8) for 12 weeks. SBS and ARI were calculated and statistical analysis was performed with the analysis of variance (SBS) or χ 2 test (ARI) to compare values between the different groups. Results. Equilibrium 2 and In-Ovation R showed a significantly lower SBS in the acidic environment than in distilled water. Significant differences in ARI scores were found for Equilibrium 2 after immersion in an acidic environment, shifting from 0 in distilled water to 2 in an acidic environment. Conclusions. Equilibrium 2 and In-Ovation R brackets showed a significant decrease in SBS after a 12-week immersion in acetic acid 3%, although all groups showed clinically acceptable SBS. Equilibrium 2 showed significant differences in ARI scores when exposed to acetic acid 3%.

Shear bond strength of self-ligating orthodontic brackets on different types of porcelain crowns

Aim: The aim of this study is to compare shear bond strength (SBS) and adhesive remnant index (ARI) of self-ligating orthodontic brackets bonded to different porcelain crowns. Materials and Methods: Three groups of different types of porcelain crowns, each containing 12 crowns were fabricated by the same technician and allocated to one of the study groups as follows: Group I - IPS porcelain crowns (Ivoclar Vivadent AG, Schaan, Liechtenstein), Group II - Porcelain fused to zirconia crowns (Zirkonzahn GmbH, Gais, Italy, Noritake Co., Tokyo, Japan) and Group III - Conventional porcelain fused to metal crowns (Ceramco3, Densply, PA, USA). The orthodontic brackets were bonded to these crowns using hydrofluoric acid (HFA) + silane etching protocol. After bonding, the SBS of the brackets were tested with a universal testing machine under standard test conditions. Results: Statistical evaluation using analysis of variance showed a significant difference between the groups (P 0.05). Chi-square comparison revealed no significant difference in ARI scores between groups (P > 0.05). Conclusions: When HFA + silane etching protocol were used, IPS crowns showed the greatest SBS of orthodontic brackets. The ARI score was non-significant. Therefore, if there is a need to place crowns over teeth then these crowns can be used for restoration of teeth before orthodontic treatment.

Effects of contamination by either blood or a hemostatic agent on the shear bond strength of orthodontic buttons

ObjectiveTo evaluate the effects of contamination by either blood or a hemostatic agent on the shear bond strength (SBS) of orthodontic buttons.MethodsWe used 45 freshly extracted, non-carious, impacted third molars that were divided into 3 groups of 15. Each tooth was etched with 37% phosphoric acid gel for 30 s. Human blood or the blood stopper agent was applied to the tooth surface in groups I and II, respectively. Group III teeth were untreated (controls). Orthodontic buttons were bonded to the teeth using light-curing composite resin. After bonding, the SBS of the button was determined using a Universal testing machine. Any adhesive remaining after debonding was assessed and scored according to the modified adhesive remnant index (ARI). ANOVA with post-hoc Tukey's test was used to determine significant differences in SBS and Fisher's exact test, to determine significant differences in ARI scores among groups.ResultsANOVA indicated a significant difference between groups (p < 0.001). The highest SBS values were measured in group III (10.73 ± 0.96 MPa). The SBS values for teeth in groups I and II were significantly lower than that of group III (p < 0.001). The lowest SBS values were observed in group I teeth (4.17 ± 1.11 MPa) (p < 0.001).ConclusionsContamination of tooth surfaces with either blood or hemostatic agent significantly decreased the SBS of orthodontic buttons. When the contamination risk is high, it is recommended to use the blood stopper agent when bonding orthodontic buttons on impacted teeth.

A Comparative Study of Shear Bond Strength of Three Different Bracket Bases Bonded to Porcelain Surfaces

Previous studies showed that the bonding strength of brackets to porcelain restorations and the failure model depend on many variables including bracket base design. The aim of this in-vitro study was to investigate Shear Bond Strength (SBS) of different bracket base designs on porcelain surfaces and to evaluate the sites of adhesive fracture with the Adhesive Remnant Index (ARI). Sixty feldspathic porcelain discs were randomly divided into three different groups each of twenty. Maxillary right incisor metal brackets with three different base designs (Victory series, 3M Unitek, Monrovia, California; Dyna-Lock, 3M Unitek, Monrovia, California and Mini Topic, Dentaurum, Inspringen, Germany) were bonded on the deglazed and conditioned porcelain surfaces in group 1, 2 and 3 respectively. Brackets were debonded and SBS was calculated in Mega Pascal (MPa). ARI scores were recorded after debonding. SBS forces calculated for group 1, 2 and 3 were 20,57 (± 7,18), 16,84 (± 6,20), 18,55 (± 5,46) MPa respectively. ANOVA and Multiple Comparison test revealed no significant difference in ARI scores between groups. Porcelain fractures after debonding were observed in groups 1 and 3. All brackets tested provided acceptable SBS. However, only Dyna-Lock brackets did not cause any porcelain fractures at debonding. This finding could be an acceptable reason to use this kind of brackets during orthodontic treatment of patient having porcelain restorations.

Reconditioning of self-ligating brackets

To test the null hypothesis that there is no significant difference in the shear bond strength (SBS) and Adhesive Remnant Index (ARI) scores of new vs reconditioned self-ligating brackets. One hundred and twenty permanent extracted bovine teeth were embedded in resin blocks. Three different new and reconditioned self-ligating orthodontic brackets (Smart Clip [3M Unitek]; Quick [Forestadent]; and Damon3MX [Ormco]) were tested. Scanning electron microphotographs of the different new (groups 1, 3, and 5) and reconditioned (groups 2, 4, and 6) bracket bases were taken before starting the experiments. Brackets were then bonded to the teeth using an orthodontic adhesive and were then tested in shear mode using an Instron Universal Testing Machine. ARI scores were then recorded. Statistical analysis was performed to determine significant differences in SBS and ARI Scores. Smart Clip and Damon3MX reconditioned brackets showed significantly lower SBS than did new ones. On the contrary, Quick reconditioned brackets showed significantly higher SBS than did new ones. No significant differences in ARI scores were found after the reconditioning process for the three different brackets tested. The in-office reconditioning procedure alters the SBS of self-ligating brackets, although SBS values still remain clinically acceptable.

A comparison of shear bond strength of immediate and delayed bonding of brackets to FRC bars using various orthodontic adhesives

Abstract Background: Fibre reinforced composite bars (FRC) have applications as bonded retainers, space maintainers and anchorage/movement units. However, the bond strength of attachments to FRC anchorage bars is unknown. Aims: To compare the shear bond strengths of brackets bonded immediately to FRCs with different orthodontic adhesive systems and bonded with the same adhesives after a 48-hour delay, abraded with a diamond bur and etched with phosphoric acid. Method: One hundred and five recently extracted upper premolars were randomly assigned to seven groups (N = 15 teeth per group). FRCs were bonded to the buccal surfaces of the teeth and stainless steel orthodontic brackets were bonded to the FRCs with the following adhesive systems: Group 0 (Tetric Flow); Groups 1, 2 and 3 (Immediate bonding with chemically cured, no-mix and light cured composites, respectively, the bars covered with Tetric Flow); Groups 4, 5 and 6 (Bonding to FRCs delayed 48 hours, then bonded with chemically cured, no-mix and light cured composites, respectively, the bars covered with Tetric Flow). The FRC bars in Groups 4, 5 and 6 were abraded with a coarse-grit diamond bur before bonding the attachments to the bars. The shear bond strengths (SBS) were measured with a universal testing machine, and the adhesive remaining on the teeth after debonding was scored with the Adhesive Remnant Index (ARI). Data were analysed using analysis of variance (ANOVA), Duncan’s post-hoc and Fisher’s Exact test. Results: There were no statistically significant SBS differences between Groups 0 (Mean SBS: 9.56 MPa), 1 (Mean SBS: 9.74 MPa), 2 (Mean SBS: 10.72 MPa) or 3 (Mean SBS: 9.54 MPa). Groups 4, 5 and 6 (Bonding delayed by 48 hours) had SBSs of 11.79 MPa, 11.63 MPa and 13.11 MPa, respectively, and were significantly higher than the SBSs in Groups 1, 2 and 3 (Immediate bonding). There were no significant differences in ARI scores among the groups. Conclusions: The mean SBSs in all groups fell within the clinically acceptable range (&gt; 7 MPa). The combination of a 48-hour delay between placement of an FRC bar and bonding an attachment, abrading the FRC with a diamond bur and etching with phosphoric acid resulted in higher bond strengths.

Changes in shear bond strength of ceramic and stainless steel brackets with different visible light curing times and directions

Abstract Background Selection of the appropriate curing time and light direction may enable the appropriate shear bond strength to be obtained and avoid enamel fracture during debonding. Aims To determine the effects of different curing times and light directions on the shear bond strengths of ceramic and stainless steel brackets. Method Ninety-two recently extracted, upper premolars were randomly assigned to six groups. Either stainless steel or ceramic brackets were bonded to the buccal surfaces of the teeth. Group 1, stainless steel brackets cured for 40 seconds from buccal surface; Group II, stainless steel brackets cured for 40 seconds from palatal surface; Group III, stainless steel brackets cured for 80 seconds from palatal surface; Group IV, ceramic brackets cured for 40 seconds from the buccal surface; Group V, ceramic brackets cured for 40 seconds from the palatal surface; Group VI, ceramic brackets cured for 80 seconds from the palatal surface. The shear bond strength was measured with a universal testing machine and the resin remaining after debonding scored with the Adhesive Remnant Index (ARI). The data were analysed with the one-way ANOVA, Tukey’s HSD test and the Kruskal-Wallis test. Associations between the ARI and shear bond strength were determined with Pearson’s correlation coefficient. Results Group IV (ceramic brackets cured for 40 seconds from buccal surface) had the highest shear bond strength (21.26 MPa) and Group II (metal brackets cured for 40 seconds from palatal surface) had the lowest shear bond strength (6.95 MPa).There was no significant difference in ARI scores among the groups. The association between the ARI scores and bond strength values was not statistically significant. Conclusions Curing from the buccal surface for 40 seconds gave unacceptably high shear bond strength values for both stainless steel and ceramic brackets. Lower shear bond strengths occurred when the light was directed from the palatal surface, but a shorter curing time is more likely to be preferred by clinicians. Future studies should investigate the possibility of reducing the curing time for both brackets.

The Influence of Er:YAG Laser Conditioning versus Self-Etching Adhesives with Acid Etching on the Shear Bond Strength of Orthodontic Brackets

The aim of this study was to compare the shear bond strength (SBS) of orthodontic brackets after acid etching, laser ablation, self-etching primer application, and combined treatments. One hundred defect-free premolars were randomly assigned to five groups. The teeth received the following treatments: group 1: phosphoric acid + Transbond XT primer; group 2: Transbond Plus Self-Etching Primer (TPSEP); group 3: Er:YAG laser ablation + Transbond XT primer; group 4: Er:YAG laser ablation + phosphoric acid + Transbond XT primer; and group 5: Er:YAG laser ablation + TPSEP. Transbond XT Adhesive Paste was used in all groups for bracket bonding. Samples were stored in deionized water at 37 degrees C for 24 h. The shear debonding test was performed at a crosshead speed of 5 mm/min. Failed brackets were examined by a stereomicroscope at 16 x magnification to determine the bond failure interface using a modified adhesive remnant index (ARI). SBS values were compared using one-way analysis of variance (ANOVA). The Kruskal-Wallis test was used for ARI scores and pairwise comparisons were done using the Mann-Whitney U test with Bonferroni correction. Mean SBS values (MPa) and standard deviations for the groups were: group 1, 13.18 +/- 3.45; group 2, 13.52 +/- 4.38; group 3, 10.33 +/- 4.74; group 4, 13.00 +/- 3.47; and group 5, 12.46 +/- 6.31. No significant differences were observed in the SBS of all the groups evaluated, but there was a significant difference in ARI scores, with group 3 showing higher ARI scores than groups 1 and 4. Er:YAG laser ablation and self-etching primer application showed similar SBS values as conventional acidetching for bonding brackets.