• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.261-270
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• 2001

The purpose of this study was to evaluate the clinical usefulness of plasma arc light which can reduce the curing time dramatically compared by shear bond strengths and failure patterns of the brackets bonded with visible light in direct bracket bonding. Some kinds of brackets were bonded with the Transbond$^{\circledR}$ to the human premolars which were embedded in the resin blocks according to the various conditions. After bonding, the shear bond strength was tested by Instron universal testing machine and in addition , the amount of residual adhesive remaining on the tooth after debonding was measured by the stereoscope and assessed with adhesive remnant index(ARI). The results were as follows : 1. When plasma arc light was used for bonding the brackets, the shear bond strength was clinically sufficient in both metal and ceramic brackets, but resin brackets showed significantly lower bond strength but which was clinically useful. 2. When metal brackets were bonded using visible light, there was no significant difference in shear bond strength due to the light-curing time and the bond strength was clinically sufficient. 3. When the adhesive failure patterns of brackets bonded with plasma arc light were observed by using the adhesive remnant index, the bond failure of the metal and resin bracket occurred more frequently at bracket-adhesive interface but the failure of the ceramic bracket occurred more frequently at enamel-adhesive interface. 4. There was no statistically significant difference of the shear bond strength and adhesive failure pattern between metal bracket bonded for 2 seconds by curing with plasma arc light and 10 seconds by curing with visible light. 6. When metal brackets were bonded using plasma arc light, the shear bond strength decreased as the distance from the light source increased. The above results suggest that plasma arc light can be clinically useful for bonding the brackets without fear of the decrease of the shear bond strength.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.215-222
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• 2000

The purpose of this study was to determine whether the application of chlorhexidine varnish affects the shear bond strength and failure pattern of orthodontic brackets or not. The experimental group consisted of 22 human premolars which extracted after chlorhexidine varnish application (4 times for 1 week interval) in vivo, and the control group consisted of 22 human premolars which extracted without any pre-treatment. After all teeth were etched with $37\%$ phosphoric acid gel, metal orthodontic brackets (Q-3002, RMO, USA) were bonded to each tooth using auto-polymerizing orthodontic resin (Ortho-One, Bisco, USA) with the same bonding procedure. The shear bond strength was measured with Instron universal testing machine (model 4466, Instron Ltd., England), and the failure pattern of each bracket was examined with Scanning Electron Microscope (SM 840A, JEOL, Japan). The data were analysed statistically with t-test. The results were as follows : 1. Application of chlorhexidine varnish had no significant effect on the shear bond strength of the orthodontic bracket. 2. There was no significant difference in the failure pattern of orthodontic bracket between the experimental group and the control group.

• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.333-342
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• 2004

The purpose of this study was to evaluate the clinical effectiveness of a plasma arc light and light emitting diode (LED), compared with shear bond strength and the failure pattern of brackets bonded with visible light in direct bonding. Brackets were bonded with Transbond XT to 60 human premolars embedded in the resin blocks according to different light-curing methods. Then, the shear bond strength of each group was measured using a universal testing machine (Instron) and the adhesive failure pattern after debonding was visually examined by light microscope. The results were as follows: 1. The shear bond strength showed no significant difference between the visible light and light emitting diode, but the plasma arc light exhibited a significantly lower shear bond strength compared with the visible light and light emitting diode. 2. In the visible light and light emitting diode, adhesive failure patterns were similar. Bond failure occurred more frequently at the enamel-adhesive interface. 3. The bonding failure of brackets bonded with plasma arc light occurred more frequently at the bracket-adhesive interface. The results of this study suggest that plasma arc light, light emitting diode and visible light are all clinically useful in the direct bonding of orthodontic brackets.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.681-688
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• 1998

The purpose of this study was to evaluate the effects of the surface treatments of resin bases in indirect bracket bonding technique by study of shear bond strengths and failure patterns. Ninety metal brackets were bonded to the stone models of specimens involving bovine lower incisor with light-cured adhesive(Light-Bond). After removal of brackets with the resin base from the stone models, the surfaces of resin bases in thirty brackets were treated with Plastic Conditioner and the surfaces of resin bases in another thirty brackets were treated with sandblaster and the remaining thirty brackets were served as controls. All brackets were transferred to the specimens and bonded using sealant. The shear bond strength was tested on universal testing machine, and failure pattern was assessed with the adhesive remnant index(ARI). The results were as follows: 1. Surface treatments of resin bases with Plastic Conditioner or sandblasting showed statistically higher shear bond strengths than no treatment group. 2. No significant difference in shear bond strength was found between Plastic Conditioner treatment and sandblasting treatment groups. 3. No significant difference in ARI scores was found among the three groups. 4. As the result of correlation analysis between shear bond strengths and hnl scores, failure at adhesive/bracket base interface tends to increase when the shear bond strength was high, but it was not significant statistically. The above results suggest that improvement of bond strength can be obtained by surface treatment of resin base in the indirect bonding technique.

• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.325-332
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• 2004

A self-etching primer that combines the etchant and primer in one chemical compound saves time and should be mote cost-effective to the clinician and patient. The purpose of this study was to evaluate the clinical effectiveness of a self-etching primer by measuring shear bond strengths according to various conditions and observing adhesive failure patterns. For this Investigation, 120 upper and lower premolars extracted for orthodontic purposes were used and randomly divided into six groups of twenty teeth each. Human premolars were embedded in a metal cylinder with orthodontic resin. Metal brackets and ceramic brackets were bonded with XT primer and self-etching primer by means of XT adhesive. Upon curing, plasma arc light and visible light were used. After bonding, the shear bond strength was tested by Instron universal testing machine, and the amount of residual adhesive that remained on the tooth after debonding was measured by stereoscope and assessed with an adhesive remnant index. The results were as fellows: 1. When brackets were bonded, if other conditions remained the same, there was no significant difference in shear bond strength due to the type of primer - either self-etching primer or XT primer. 2. When metal brackets were bonded, there was no significant difference in shear bond strength according to the source of light - plasma arc light or visible light - and type of primer. 3. There was a very significant difference in shear bond strength according to the type of brackets - metal or ceramic brackets. The shear bond strength of ceramic brackets was stronger than metal brackets. 4. When the adhesive failure patterns of metal brackets bonded with self-etching primer were observed by using the adhesive remnant index, the bond failure of the metal bracket occurred more frequently at the bracket-adhesive. The failure of the ceramic bracket, however, occurred more frequently at the enamel-adhesive interface. The adhesive failure patterns of metal brackets bonded with XT primer observed the same patterns. The above results suggest that self-etching primer can be clinically useful for bonding the brackets without fear of a decrease in shear bond strength.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.493-502
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• 1997

This study was conducted to evaluate the tensile bond strength by bonding the dental bracket with Super-bond after treating the surface of dental Nickel-Chromium alloy with sandblasting, sandblasting & tin-plating, respectively, and tin-plating. 10 pieces of Nickel-Chromium alloys with brackets bonded with Super-bond without their surface treatment were sampled as a control group, 20 pieces of Nickel-Chromium alloy brackets bonded with Super-bond after treating them with sandblasting as group I, 20 pieces of Nickel-Chromium alloys tin-plated and bonded with Super-bond after sandblasting as group II, and then 20 pieces of alloys with brackets bonded with Super-bond after tin-plating as group III. The result of those examination and comparison is summarized as follows: 1. Group I showed the mean tensile bond strength of $14.41{\pm}2.24MPa$ which was highest among 4 groups, followed by group III($13.59{\pm}.51MPa$), group II($12.27{\pm}.45MPa$), and control group($10.50{\pm}1.57MPa$), respectively. However, it was shown that there was no statistically significant difference between group I and III, group III and II, and group II and control group(p>0.05). 2. The main failure pattern of those brackets showed that $70\%$ of the control group had an adhesive failure at the bracket-Superbond interface, and $30\%$ at the Nickel-Chromium alloy-Superbond interface, while other groups did the adhesive failure at the bracket-Superbond interface. 3. When examined under SEM, it was shown that adhesives were mostly attached to the surface of the Nickel-Chromium alloy for all groups while a considerable quantity of adhesives were attached to the bracket base. Then, those samples treated only with sandblasting showed the most even and remarkable roughness of their surface.

• The korean journal of orthodontics
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• v.36 no.5
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• pp.331-338
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• 2006

Objective: The purpose of this study was to evaluate whether the bond strength of polycarbonate brackets can be increased through surface treatment. Methods: One hundred polycarbonate brackets (Alice) were bonded to bovine incisors with light-cured adhesive. The bracket bases were treated with one of three methods; sandblasting, plastic conditioner application, and combined treatment with sandblasting and plastic conditioner. The brackets without any suraace treatment served as the control. The shear bond strength was tested with a universal testing machine, and failure pattern was assessed with the adhesive remnant index. Results: The shear bond strength in all experimental groups was higher than that of the control group (p < 0.001). The group treated with plastic conditioner after sandblasting showed statistically higher shear bond strength than the sandblasting only group to (p < 0.05). The group treated with plastic conditioner after sandblasting showed higher shear bond strength than plastic conditioner only group, but the difference was not statistically significant. Conclusion: The above results suggest that the surface treatments of polycarbonate bracket is mandatory to improve bond strength, and the most effective method is an application of plastic conditioner after sandblasting.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.207-215
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• 2005

This study was performed to evaluate clinical practicality of the rebonding method with flowable resin without the removal of the residual resin on the debonded theeth and debonded bracket base after debonding. The samples of the control group (group I) were rebonded with Transbond XT using the usual rebonding method after the residual resin was removed. At experimental group, the brackets were rebonded with Transbond XT(group II) and CharmFil Flow (group III) without removal of residual resin which is the possibility becoming the index (or rebonding to similar position With initial bonding. The Shear bond Strength of the each group was measured. Patterns of bonding failure were evaluated with modified ARI score. and the shear bond strength according to patterns of bonding failure at experimental group was compared. Between the control group $(6.51\pm1.21MPa)$ and the group II rebonded with Transbond XT $(6.30\pm1.01MPa)$ did not have significantly difference in the shear bond strength (p=0.534), and the shear bond strength of group II was Significantly lower 4han the group III rebonded With CharmFil Flow $(7.29\pm1.54 MPa)$ (P=0.009). At control group, there was not large difference if distribution of bending failure pattern. But at experimental group, bond failure did not occur in interface between the resin-enamel. and bond failure between the resin-bracket, within the resin was distributed similarly. There was not significantly difference in the shear bond strength according to patterns of bonding failure at experimental group (P>0.05) The result of this study showed that the method suggested in this study aid flowable resin as rebonding adhesive could be useful in clinically.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.275-282
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• 2008

Objective: The purpose of this study was to investigate the effect of using laser for ceramic bracket bonding of porcelain surfaces and to compare it with conventional treatment of porcelain surfaces. Methods: Ninety feldspathic porcelain specimens were divided into 9 groups of 10, with each group having different surface treatments performed. Surface treatment groups were orthophosphoric acid, orthophosphoric acid with silane, hydrofluoric acid, hydrofluoric acid with silane, sandblasted, sandblasted with silane, laser etched, laser etched with silane, and glazed surface served as a control group. In the laser etched groups, the specimens were irradiated with 2-watt superpulse carbon dioxide ($CO_2$) laser for 20 seconds. Ceramic brackets were bonded with light-cure composite resin and all specimens were stored in water at $37^{\circ}C$ for 24 hours. Shear bond strength was determined in megapascals (MPa) by shear test at 1 mm/minute crosshead speed and the failure pattern was assessed. For statistical analysis, one-way ANOVA and tukey test were used. Results: Statistical analysis showed significant differences between the groups. The HFA + S group showed the highest mean shear bond strength ($13.92{\pm}1.94\;MPa$). This was followed by SB + S ($10.16\;{\pm}\;1.27\;MPa$), HFA ($10.09\;{\pm}\;1.07\;MPa$), L + S ($8.25\;{\pm}\;1.24\;MPa$), L ($7.86\;{\pm}\;0.96\;MPa$), OFA + S ($7.22\;{\pm}\;1.09\;MPa$), SB ($3.41\;{\pm}\;0.37\;MPa$), OFA ($2.81\;{\pm}\;0.37\;MPa$), G ($2.46\;{\pm}\;1.36\;MPa$), Bond failure patterns of HFA and silane groups, except L + S, were cohesive modes in porcelain while adhesive failure was observed in the control group and the rest of the groups. Conclusions : A 2-watt superpulse $CO_2$ laser etching of porcelain surfaces can provide a satisfactory result for porcelain surface treatment for ceramic bracket bonding. Laser irradiation may be an alternative conditioning method for the treatment of porcelain surfaces.

• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.293-300
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• 2002

The purpose of this study was to evaluate the clinical effectiveness of hydrophilic primer, which claim to retain adequate bond strength on moistened enamel resulting from moisture or saliva contamination, by comparing the shear bond strength and adhesive failure patterns of brackets bonded using hydrophilic primer and conventional hydrophobic primer. Brackets were bonded to human premolars embedded in metal cylinders utilizing light cured adhesive, primed with either a hydrophilic primer(Transbond fm primer) or a conventional hydrophobic primer(Transbond XT primer). Each sample was exposed to varying degrees of artificial saliva contamination during the priming process. The shear bond strength was measured using a universal testing machine, and the adhesive failure patterns after debonding were visually examined by strereomicroscope and assessed using the adhesive remnant index(ARI). The results were as follows 1. In dry conditions, no significant differences in shear bond strength between Transbond W and Transbond XT primers were found. 2. Transbond MIP primer exhibited a significantly higher shear bond strength than Transbond XT primer in saliva-contaminated conditions, regardless of the degree of contamination. 3. When contaminated with one coat of saliva, Transbond MIP primer did not exhibit significant differences in shear bond strength compared to the dry condition. When contaminated with two coats of saliva, Transbond MIP primer exhibited a singnificantly lower shear bond strength compared to the dry condition. 4. The adhesive remnant index of the adhesive failure pattern had a tendency to decrease, as the degree of saliva contamination increased. Bracket-adhesive interface failure was observed in more than half of the saliva contaminated samples utilizing Transbond MIP primer, whereas the bond failure sites of the Transbond XT primer samples occurred almost exclusively at the adhesive-enamel interface in saliva-contaminated conditions. The results of this study suggest that in cases where moisture control is difficult, Transbond MIP primer is an effective alternative to conventional hydrophobic primers.