• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.781-789
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• 1997

The purpose of this study was to evaluate the effects of fluoride relasing orthodontic sealant on the shear bond strength of light-and chemical-cured orthodontic rosins, to compare the shear bond strenth with light-and chemical-cured orthodontic resins, and to identify the changes of shear bond strength by rebonding in vitro. The brackets were divided into eight groups. Each group of metal brackets had different bonding mechanisms with adhesives. Group A : Transbond only Group B : Mono-Lok 2 only Group C : Light cured FluoroBond+Transbond Group D : Light cured FluoroBond+Mono-Lok 2 Group E : Transbond only(rebonded) Group F : Nomo-Lok 2 only(rebonded) Group G : Light cured FluoroBond+Transbond(rebonded) Group H : Light cured FluoroBond+Mono-Lok 2(rebonded) 65 extracted human premolars were prepared for bonding and 65 metal brackets for each group were bonded to prepared enamel surfaces of buccal surfaces as the above prescription. 24 hours bonding after, the Instron universal testing machine was used to test the shear bond strength of metal brackets to enamel. After debonding, same kind of metal brackets for each group were rebonded to prepared enamel surfaces of buccal surfaces to test the shear bond strength at the rebonding to enamel. Statistical analysis of the data was carried out Student's t-test ANOVA test, and Scheffe test using $SPSS/PC^+$ The results were as follows : 1. The order of shear bond strength was Group B(11.84MPa), Group A(10.75MPa), Group, D(9.69MPa), and Group C(9.39MPa)in lst bonded groups. 2. The order of shear bond strength was Group E(7.40MPa), Group G(6.48MPa), Group F(5.89MPa), and Group H(5.15MPa) in rebonded groups. 3. The shear bond strength of chemical cured orthodontic rosins had higher than that of light-cured orthodontic resins in all groups, but there was no statistical significance between groups(P>0.05). 4. In rebonded groups, the shear bond strength of light cured orthodontic rosins had higher than that of chemical cured orthodontic resins, but there was no statistical significance between groups(P>0.05). 5. The shear bond strength of all rebonded groups progressively decreased than that of 1st bonded groups, and there was statistical significance between groups(p<0.05, p<0.001).

• The korean journal of orthodontics
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• v.29 no.3 s.74
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• pp.361-374
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• 1999

Intraoral filled type of orthodontic appliance can cause reversible or irreversible damages such as gingivitis, periodontitis, enamel decalcification, dental caries, root resorption, and pulpal changes. Such adverse effects are brought by increase in dental plaque as well as oral flora. Such an increase causes gingival inflammation and enamel decalcification. The purpose of this study is to get klowledge on initial changes in dental plaque, gingivitis, and enamel decalcification after bonding fixed orthodontic appliances according to time flow, gender, and sides(right/left) of premolar region. For control group, 48 students of dental college, Yonsei university(26 males, 22 females) were chosen; for experimental group, 73 orthodontic patients(36 males, 37 females) who will be treated with fixed appliances were chosen. All the subjects had no systemic disease, juvenile periodontitis and all the females had passed their ,menarche. Tooth brushing instruction was given to all the subjects prior to the experiment. For control group, plaque index, gingival index, and decalcification index were measured twice at 3 weeks interval ; for experimental group, the same was done prior to, 3, 6, 9 weeks after bonding fixed appliances. The following results were obtained: 1. In plaque index 3 weeks after placement of appliances, and it showed gradual increase afterwards. 2. In gingival index3 weeks after placement of appliances, and afterwards it showed increase at a faster rate than plaque index. 3. Enamel decalcification began to show between 3 and 6 weeks after bonding fixed appliances. Decalcification index began to increase 6 weeks after appliance placement, but there was no statistical significance. 4. When the comparison was made between two sides of premolar region, the right side showed greater index in plaque and gingival index of experimental group.

• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.289-296
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• 1992

The purpose of this study was to evaluate and compare the shear bond strengths and failure sites of metal brackets bonded with chemically cured adhesive and light-cured adhesive. 10 brackets were bonded on prepared enamel surfaces with $Transbond^{circledR}$ (Unitek/3M; U.S.A.) light-cured orthodontic adhesive and another 10 brackets were bonded with $Ortho-one^{\circledR}$ (Bisco:U.S.A.) chemically cured orthodontic adhesive. 24 hours after bonding, the Instron universal testing machine was used to measure the shear bond strengths. The failure sites were examined under streoscopic microscope. The results were as follows: 1 . The mean shear bond strength of metal brackets bonded with light-cured adhesive was lower than that of metal brackets bonded with chemically cured adhesive, but the difference was not statistically significant (p < 0.05). 2. Regardless of the type of adhesives, the brackets were failed primarily at the bracket base-adhesive interface. 3. Bonding of metal brackets with light-cured adhesive is considered to be clinically acceptable.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.85-90
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• 1986

The purpose of this study was to compare the tensile bond strength of Comspan and Panavia as a luting materials between electrochemically etched Ni-Cr-Be alloy castings and acid etchea human tooth enamel. Tensile bond strength was evaluated using an Instron testing machine at a crosshead speed of 2mm/min. The following conclusions can be drawn frfm this study ; 1. The tensile bond strength of etched-metal resin-bonded specimen was $179.0{\pm}42.5kg/cm^2$ in case of Comspan and $169.6{\pm}41.4kg/cm^2$ in case of Panavia. 2. The tensile bond strength was not significantly different between Comspan, using with bonding agent, and Panavia, using without bonding agent.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.196-203
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• 2003

The application of sealants is a highly technique-sensitive procedure, requiring an extremely dry field prior to placement. Moisture contamination of the etched enamel surface before sealant placement is cited as the main reason for sealant failure. The purpose of this study was to evaluate the effects of different methods of sealant application on the shear bond strength of sealants to enamel. In groups 1, 2, 3, 4 Teethmate(unfilled sealant) was used, while Ultraseal XTplus(filled sealant) was used in groups 5, 6, 7, 8. Groups 1 and 5(control) were acid etched for 15 seconds using 35% phosphoric acid, washed and then dried. In groups 2, 6 drying agents were applied, and in groups 3, 7 bonding agents were applied and light cured. In groups 4 and 8 both drying agent and bonding agent were applied. Then sealant was cured to the specimen using molds 3mm in diameter and 2mm in height. Thermocycling was performed and shear bond strength was finally measured. The following results were obtained : 1. Groups using filled sealant(groups 5, 6, 7, 8) showed higher shear bond strengths compared to groups using unfilled sealant(groups 1, 2, 3, 4). 2. Among groups using unfilled sealant(groups 1, 2, 3, 4), groups 2, 3, 4 showed significantly higher shear bond strength compared to group 1(p<0.05). There were no significant differences among groups 2, 3 and 4. 3. There were no significant differences(p>0.05) among groups using filled sealant(groups 5, 6, 7, 8). 4. When modes of fracture were examined, cohesive failure was observed in groups 2, 3 and 4.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.619-627
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• 2008

The objective of this study was to compare the microleakage of five adhesive systems in the enamel and dentin of permanent teeth. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on both buccal and lingual surfaces of 25 extracted human molar teeth. The tested adhesives were: Adper Scotchbond Multi-purpose Plus Adhesive (SM), Adper Single bond 2 (SB), Clearfil SE Bond (SE), Adper Prompt L-Pop (PL) and G-Bond (GB). The results were as follows: 1. At the enamel margins, PL showed the highest leakage value(0.85), and others showed values of SB(0.55), GB(0.50), SM(0.35) and SE(0.25) in decreasing order. There were statistically significant differences in PL vs. SM and PL vs. SE(p<0.05). 2. At the dentin margins, GB showed the highest leakage value(2.10), and others showed values of SE(1.45), PL(1.40), SB(1.05), SM(0.70) in decreasing order. There were statistically significant differences in GB vs. SB and GB vs. SM(p<0.05). 3. Dentin margins showed high dye penetration rate than enamel margins in all material tested groups and there were statistically significant differences for SE, PL and GB.

• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.439-447
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• 2004

The purpose of this study was to investigate the influence of water, saliva and blood contamination on the bonding strength of metal brackets with a self-etching primer/adhesive to enamel. Ninety-six extracted human teeth were divided into four groups. The brackets were bonded to enamel with a self- etching primer (3M/Unitek Dental Products. Monorovia California) according to one of four protocols. The teeth were bonded in a dry condition (group D) or in contamination with distilled water (group W), artificial saliva (group S). or fresh human blood (group B) Shear bond strengths were tested using an Instron Universal testing machine. After debonding. bracket and tooth surfaces were examined with a stereomicroscope. In each group, four samples were selected and examined with a Scanning electron microscope of the prepared enamel surface and resin-enamel interlace. The results obtained were summarized as follows: Shear bond Strength if group D $(15.22{\pm}2.86MPa)$ and W $(15.20{\pm}3.85 MPa)$ Were higher than in group B$(12.56{\pm}2.94MPa)$ (p<0.05). There were no statistical differences in the shear bond strengths between groups D. W and S (p>0.05). There was a tendency to have less residual adhesive remaining on the enamel surfaces of group B than group D. The SEW morphology of group D and W showed a more roughened etching pattern than group S and B. Water or saliva contamination on bending of orthodontic brackets with Transbond plus self etching primer had almost no influence on bond strength In this study, the blood contaminated group showed the lowest bond strength, but it was above the clinically acceptable bond strength (5.9-7.8 MPa, Reynold, 1975). The results of this study suggest that acceptable clinical bond strengths can be obtained in wet conditions when self-etching adhesives are used.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.791-800
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• 1997

Sixty premolars extracted for orthodontic treatment were divided into four groups, and the residual resin was removed with four different rotary finishing instruments at a fixed speed of $18,500{\pm}300 rpm$ on the low speed handpiece. The instruments were G1; No.169L carbide fissure bur, G2: No.2 round bur, G3; No.4 round bur, G4: No.8 round bur. Then, the enamel received a S-second polishing with a rubber cup and a pumice. To find the extent of loss on the enamel at this point, prophylaxis was done with the rubber cup and pumice prior to bonding of the bracket(P1) and removal of residual resin by means of appropriate procedure applicable to each respective group(P2) followed. The final polishing was done with the rubber cup and pumice(P3), and the enamel surface roughness was measured each by the surface measuring instrument. The whole process was observed under a scanning electron microscope to gain the following results: At P2, the enamel surface roughness in G1 showed most smoothly with $2.60{\pm}0.55{\mu}m;\;in\;G2,\;3.24{\pm}0.80{\mu}m;\;in\;G3,\;3.44{\pm}0.94{\mu}m;\;in\;G4,\;3.89{\pm}0.54{\mu}m$, the roughest. G2 and G3 showed no statistical significance(P>0.05). At P3, the enamel surface roughness in G1 showed most smoothly with $2.29{\pm}0.47{\mu}m;\;in\;G2,\;2.44{\pm}0.56{\mu}m;\;in\;G3,\;2.44{\pm}0.56{\mu}m;\;in\;G4,\;2.92{\pm}0.43{\mu}m$, the roughest. G1 vs G2, G3, and G2 vs G3 had no statistical significances(p>0.05). In all groups, P2 and P3 showed rougher in surface roughness than P1, and P2 rougher than P3(p<0.01). In a case of 5-second prophylaxis with the rubber cup and the pumice on a virgin, normal enamel, fine scratches were found under the scanning electron microscope. In all four groups, unremovable gouges remained even after polishing with the ubber and pumice; residual resin was not observed with naked eye when finished with the rubber and pumice, but the resin debris was observed under the scanning electron microscope.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.771-779
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• 1997

The purpose of this in vitro study was to evaluate the effects of different acid etching times on the enamel surface morphology, shear bond strength and debonding failure mode of orthodontic attachment. Ninety six extracted human mandibular premolars were divided into eight groups of twelve teeth. The buccal surfaces were etched with $37\%$, phosphoric acid for 5, 10, 15, 30, 45, 60, 90 and 120 seconds, respectively. Two teeth from each group were used for scanning electron microscope examination. On the etched buccal surfaces of remaining teeth, orthodontic attachments(lingual buttons) were bonded with light cured orthodontic adhesive. Twenty foot hours after bonding, a Instron universal testing machine was used to determine shear bond strength of orthodontic attachment to enamel. After debonding, bases of orthodontic attachments and enamel surfaces were examined under stereoscopic microscope to determine failure mode. Statistical analysis of the data was carried out with one nay ANOVA and Duncan's multiple range test The results were as follows; 1. There was no statistically significant difference in shear bond strengths between the various etching times(p<0.05). 2. The failure modes of orthodontic attachments had some differences. In 5, 10 and 15 seconds etching groups, the percentage of adhesive/enamel interface failure was higher than that of adhesive/attachment interface failure. On the contrary, in 30, 45, 60, 90 and 120 seconds etching groups, the results were reversed. 3. The etching patterns of enamel surfaces had a great variation. So, we could not find any correlation between etching pattern and bond strength. 4. The findings in this study indicate that in vitro reduction of the etching me to 5 seconds maintains clinically acceptable bond strength. However, further study is required to determine the cause of failure mode in 5, 10 and 15 seconds groups.

• The korean journal of orthodontics
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• v.23 no.1 s.40
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• pp.75-88
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• 1993

Recent reports indicate that shorter etching times than 60 seconds can be adopted without affecting the bond strength and clinical disadvantages. The purpose of this in vitro study was to compare the shear bone strength and to measure depth of etch at different etching time length. One hundred and eight extracted bovine lower central incisors were embedded each in a tooth cup with cold-cure acrylic resin. The facial surfaces of the teeth were ground wet with 600-, 800-, 1000-, and 1200-grit Sic papers, and finally polished with a water slurry of extrafine silicon carbide powder, washed with tap water, and dried with hot air. Nine groups of nine prepared teeth were etched with a commercial($38\%$ phosphoric acid solution) for 0, 5, 10, 15, 20, 30, 60, 90, and 120 seconds, respectively, rinsed with tap water, and dried with hot air. One conditioned teeth from every group was selected randomly for the scanning electron microscopic examination, and the remaining eight teeth of the groups were used for measuring the push shear bond strength after bonding brackets and immensing them in the $36.5^{\circ}C$ water for 24 hours. Another nine groups of three teeth were used for measuring the depth of etch and surface roughness with a surface profilometer. after pieces of adhesive tape of 3mm inner diameter positioned on the ground enamel surfaces, and etched with the above mentioned. The data obtained form the above expeiments were analysed statistically with one way ANOVA and Dunkan's multiple range test with the $95\%$ confidence level. The results and conclusion of the study were as follows; 1. The results of shear bond strength for the given experimental etching times were not statistically different, but showed the tendency of decreasing shear bone strength after over 60 seconds etching times. 2. On the scanning election microscopic examination, it was observed that the morphological patterns of etched enamel surface for 5 to 20 seconds were similar and consitent, and those for 30 to 120 seconds showed increasing over-etched patterns depending on the length of etching times. 3. The depth of etch was increased almost proportionally by the length of etching times, but it was not associated with the shear bond strength. 4. The surface roughness increased depending on the length of etching times, but it was not associated with the shear bond strength. 5. This experiment indicated that proper etching time with $38\%$ phosphoric acid solution is in the range of 5 to 30 seconds.