• The korean journal of orthodontics
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• v.42 no.1
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• pp.17-22
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• 2012

Objective: To study and compare the effects of different demineralization-inhibition methods on the shear bond strength (SBS) and fracture mode of an adhesive used to bond orthodontic brackets to demineralized enamel surfaces. Methods: Eighty freshly extracted, human maxillary premolars were divided into 4 equal groups and demineralized over the course of 21 days. Brackets were bonded to the demineralized enamel of teeth in Group 1. In Group 2, bonding was performed following resin infiltration ($ICON^{(R)}$, DMG, Hamburg, Germany). Before bonding, pre-treatment with acidulated phosphate fluoride (APF) or solutions containing casein phosphopeptide-amorphous calcium phosphate with 2% neutral sodium fluoride (CPP-ACP/wF) was performed in Groups 3 and 4, respectively. The SBS values of the brackets were measured and recorded following mechanical shearing of the bracket from the tooth surface. The adhesive remnant index (ARI) scores were determined aft er the brackets failed. Statistical comparisons were performed using one-way ANOVA, Tukey's post-tests, and G-tests. Results: Significant differences were found in some of the intergroup comparisons of the SBS values (F = 39.287, p < 0.001). No significant differences were found between the values for the APF-gel and control groups, whereas significantly higher SBS values were recorded for the resin-infiltrated and CPP-ACP/wF-treated groups. The ARI scores were also significantly different among the 4 groups (p < 0.001). Conclusions: Tooth surfaces exposed to resin infiltration and CPP-ACP/wF application showed higher debonding forces than the untreated, demineralized surfaces.

• The korean journal of orthodontics
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• v.43 no.5
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• pp.242-247
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• 2013

Objective: To test the null hypothesis that no difference exists between the effects of at-home bleaching and in-office bleaching on shear bond strength (SBS) with bracket bonding at 4 different time intervals after dental bleaching. Methods: Ninety extracted human premolars were randomly divided into 9 groups (n = 10) according to the bleaching methods used (at-home bleaching and in-office bleaching) and the storage time in artificial saliva (30 min, 1 day, 2 weeks, and 3 weeks before bonding). The control group was stored in artificial saliva for 7 days. Brackets were bonded with the Transbond XT adhesive system, and SBS testing was performed. The adhesive remnant index (ARI) was used to assess the amount of resin remaining on the enamel surfaces after debonding. The SBS data were analyzed by analysis of variance (ANOVA) and the Tukey test. For the ARI, the Kruskal-Wallis test was performed. Significance for all statistical tests was predetermined to be p < 0.05. Results: The SBS of the unbleached group was significantly higher (p < 0.05) than that of the bleached groups (except for the group bonded 30 min after at-home bleaching). Conclusions: The null hypothesis was not totally rejected. All bleaching groups tested had decreased SBS of the brackets to the enamel, except for the group bonded 30 min after at-home bleaching. The SBS returned to values close to those of the unbleached enamel within 3 weeks following bleaching.

• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.137-147
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• 2001

Acidic primer is the bonding agent which combines the conditioning and priming agent into the single solution and was originally developed for the dentin bonding system. It is less harmful to the tooth structure and more convenient to manipulate than the traditional etching procedure. The Purpose of this study is to evaluate the shear bond strength of various bonding materials when the enamel is treated with acidic primer for the bracket bonding procedure. Fifty recently extracted human premolars were randomly separated into five groups -Group I using Clearfil Liner Bond 2 adhesive system to the enamel treated with acidic primer, Group II using Transbond XT adhesive system to the enamel treated with acidic primer, Group III using panavia 21 adhesive system to the enamel treated with acidic primer, Group IV using Fuji-Ortho LC adhesive system to the enamel treated with acidic primer, Group V using Transbond XT adhesive system to the enamel treated with 37$\%$ phosphoric acid. The shear bond strength was measured with Instron universal testing machine after storing in $37^{\circ}C$ water bath for 48 hours. After debonding, the teeth and brackets were examined under scanning electron microscope (SEM) and assessed with the adhesive remnant index (ARI). The results were as follows : 1. There were no significant differences in shear bond strength between group III ($8.69{\pm}2.72MPa$), group IV (9.7 ± 3.16 MPa), and group V ($10.48{\pm}2.60MPa$) (p>0.05). 2. The shear bond strength of group III and group IV was significantly higher than that of group I ($1.09{\pm}0.53MPa$), and Group II ($2.70{\pm}1.46MPa$) (p<0.05). 3. The ARI of group IV ($2.1{\pm}1.1$) and group V ($2.9{\pm}0.3$) was significantly higher than that of group I ($0.2{\pm}0.4$), group II ($0.3{\pm}0.9$) and group III ($0.2{\pm}0.4$) (p<0.05). 4. There were no significant difference between the ARI of group IV and group V (p>0.05). This result suggests that the combination of acidic primer and some bonding adhesive can provide sufficient shear bond strength for clinical orthodontics.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.341-349
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• 2017

Blood decontamination is an important factor in success of the orthodontic bracket. The purpose of this study is to evaluate the shear bond strength affected by blood decontamination. The shear bond strength was measured on blood decontamination before and after primer photopolymerization. And the adhesive remnants type and surface patterns was evaluated under scanning electron microscopy. A total of 50 human premolars were prepared. Group I was attached using conventional resin-acid etching method as control group. Group II and III were blood contaminated before curing primer and groups IV and V were blood contaminated after curing primer. Group II and IV were treated only with cotton pellet and Groups III and V were treated with cotton pellet after water washing. The mean shear bond strengths were in the order of groups I, V, III, II, and IV. In scanning electron micrographs group III and V showed more uniform surface than group II and IV. The ARI was significantly different between the control group and the experimental groups (p <0.05).

• The korean journal of orthodontics
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• v.43 no.5
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• pp.235-241
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• 2013

Objective: The purpose of this study was to investigate whether extension of the custom base is necessary for enhancement of bond strength, by comparing the debonding forces and residual adhesives of 3 different lingual bracket systems. Methods: A total of 42 extracted upper premolars were randomly divided into 3 groups of 14 each for bonding with brackets having (1) a conventional limited resin custom base; (2) an extended gold alloy custom base: Incognito${TM}$; and (3) an extended resin custom base: KommonBase${TM}$. The bonding area was measured by scanning the bracket bases with a 3-dimensional digital scanner. The debonding force was measured with an Instron universal testing machine, which applied an occlusogingival shear force. Results: The mean debonding forces were 60.83 N (standard deviation [SD] 10.12), 69.29 N (SD 9.59), and 104.35 N (SD17.84) for the limited resin custom base, extended gold alloy custom base, and extended resin custom base, respectively. The debonding force observed with the extended resin custom base was significantly different from that observed with the other bases. In addition, the adhesive remnant index was significantly higher with the extended gold alloy custom base. Conclusions: All 3 custom-base lingual brackets can withstand occlusal and orthodontic forces. We conclude that effective bonding of lingual brackets can be obtained without extension of the custom base.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.271-277
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• 1985

With modification of the acid etch technique and improvements of the physical and mechanical properties of the acrylic resin, the removal of directly bonded attachments and the finishing of the underlying enamel have become an acute clinical problem. This study was to evaluation the efficacy of recently introduced instrumentation and techniques to remove bonded brackets and residual resin, and restore the affected enamel surface to an acceptable clinical condition. Fortyeight premolar which were scheduled for extraction for orthodontic purposes were bonded with brackets using super-C ortho. Four additional premolars with untreated surfaces were used as controls. After one weak the brackets were removed and the residual resin removed by hand scaler, green stone, green rubber wheel, sandpaper disc, tungsten carbide bur, Sof-lex disc. Half the experimental teeth were given a final pumicing and then all were extracted and stored in 50 percent ethanol. The scanning electron microscopy was used to evaluated the enamel surface. Following results were obtained; 1. A satisfactory result was obtained by means of the Sof-lex disc. 2. The order of the scratch formation was the procedure using hand scaler, green atone, tungsten carbide bur, sandpaper disc, green rubber wheel, and Sof-lex disc. 3. The procedures using green stone and tungsten carbide bur showed many groove formations and the other procedures showed none. 4. final pumicing serves effectively to remove residual adhesive and restore the enamel surface.

• The korean journal of orthodontics
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• v.37 no.4
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• pp.283-292
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• 2007

The purpose of this study was to evaluate the clinical usefulness of 4 self etching primers by measuring the shear bond strength of orthodontic brackets and examining the failure pattern of bracket-tooth interfaces. Methods: Seventy-five, defect-free, premolars were randomly assigned into five groups: control group (37% phosphoric acid + Transbond XT primer) and self etching primer treated groups (Transbond Plus self etching primer, Unifil bond, Clearfil SE bond, and Adhese). The shear bond strength was measured with a universal testing machine and the amount of residual adhesive remaining on the brackets after debonding was assessed by the adhesive remnant index (ARI). Results: The results showed that the groups conditioned with self etching primer had significantly lower shear bond strength than the control group (p < 0.05), although clinically acceptable. However, there were no significant differences in shear bond strength among the self etching primer groups (p > 0.05). Evaluation of the ARI scores indicated there was less resin remnant on the teeth in the groups conditioned with self etching primers, although not statistically significant. Conclusion: The results of this study suggest that all four of the self etching primers have shown acceptable bond strength for clinical use.

• The korean journal of orthodontics
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• v.33 no.1 s.96
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• pp.51-61
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• 2003

The purpose of this study was to evaluate the effects of a self-etching primer on the shear bond strength of orthodontic brackets and on the failure pattern of bracket-adhesive interfaces in dry or wet condition. Brackets were bonded to extracted human teeth according to one of three experimental protocols. In the Group P, teeth were etched with $37\%$ phosphoric acid. After the Transbond XT Primer was applied onto the etched surfaces, the brackets were bonded with Transbond XT(3M, Unitek, Monrovia, Calif) and light cured for 40 seconds. In the Group SD, a self-etching primer(3M, Unitek, Monrovia, Calif) was placed on the enamel for 3 seconds and gently evaporated with air, as suggested by the manufacturer. The brackets were then bonded with Transbond XT as in the Group P In the Group SW, artificial saliva was applied to the enamel surface for 10 seconds to allow complete hydration of the surface before application self-etching primer The brackets were then bonded following the procedures of Group SD. Each group was divided into 2 sub-groups(0.5h, 24h) according to debonding time. Shear bond strengths were measured by Instron universal testing machine. After debonding, the teeth and brackets were examined under scanning electron microscope and assessed with the adhesive remnant index. The result obtained were summarized as follows ; 1. The shear bond strengths were high enough to use clinically in all testing groups, but the shear bond strengths of Group SD and SW were significantly lower than Group P(p<0.05). 2. With respect to comparison of debonding time, 24h debonding samples exhibited heigher shear bond strength than 0.5h debonding samples in Group P, SD and SW(p<0.05). 3. In the self etching primer groups(Group SD and Group SW), there was no significant difference in mean shear bond strength between under dry and wet state(p>0.05). 4. There was a greater frequency of ARI score of 0 and 1 with the Group P. On the other hand, there was a higher frequency of ARI scores of 2 and 3 with Group SD and Group SW(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.491-497
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• 2006

Orthodontic seamless bands are frequently used in pediatric dentistry. In the process of seating bands with luting cement coated inside, not uniformed coating might bring about various problems such as enamel decalcification and/or gingivitis, and this clinical trial was made to review several band-seating methods to exclude these risks. One kind of band luting cement and one size of seamless bands were used on the resin replicas of an extracted maxillary and mandibular 1st molar with three different seating methods 1. seating the band with the luting cement coated only inside the band, 2. seating the band with the luting cement coated inside the band and on axial surfaces of the teeth, 3. seating the band with the adhesive tape on the occlusal opening of the band and the luting cement coated only inside the band. After cement was completely set, bands were peeled off from the teeth and the status of cement coating was evaluated. With this experiment more uniformed coating of the luting cement was found in latter two groups. These methods are thought more appropriate to almost completely rule out the risk of unevenly coated cement beneath the bands by conventional method.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.87-94
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• 2010

Objective: Many studies have carried out research on comparisons between laser etching and conventional etching systems to investigate methods of reinforcing shear bond strength. The purposes of this study were to assess the efficiency of bonding with erbium, chromium doped: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser etching combined with the conventional etching technique. Methods: Sixty-four sound premolars, extracted for orthodontic purposes, were randomly divided into 4 groups and treated in the following manner. First group, conventional etching of 37% phosphoric acid for 15 seconds (control); second group, 1.5 W laser etching for 10 seconds followed by conventional etching; third group, conventional etching followed by 1.5 W laser etching; fourth group, 1.5 W laser etching for 15 seconds only. We assessed the shear bond strength, the surface characteristics, and the adhesive remnant index scores between all groups. Results: Experimental groups showed higher shear bond strength than the control group. But no statistically significant differences were found between the second and third groups. Adhesive remnant scores were compared with the Kruskal-Wallis test, and no statistically significant differences were found between all groups. Conclusions: To obtain maximum shear bonding strength, a combined technique of Er,Cr:YSGG and 37% phosphoric acid is useful even though it may be inconvenient.