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Effects of different prophylactic pastes on the shear bond strength of orthodontic brackets
d e n t a l m a t e r i a l s 2 9 S ( 2 0 1 3 ) e1–e96
LH-20 and high-resolution fractions (#1–40) were produced. Firstly, these fractions were combined into 6 fractions (low resolution) according to a thin layer chromatography profile. To assess the fractions (6.5%, w/v relative concentration), dentin beams (1.7 mm × 0.5 mm × 6 mm) were prepared from extracted human molars. Beams were fully demineralized using 10% phosphoric acid solution for 5 h and divided into groups (n = 5). The modulus of elasticity was assessed at baseline and after 1 h in their respective solutions. A 3-point bending test was employed at 3% strain, and data (MPa) were calculated as fold increase. Afterwards, the most active solutions were selected and the corresponding individual high-resolution fractions were tested (#19–40). Beams were treated as described before and the modulus of elasticity was evaluated. The same specimens were used to assess biodegradation using bacterial collagenase (100 g/ml Clostridium histolyticum) for 24 h at 37 ◦ C, and data dry mass loss was calculated. Results: Considering the high-resolution fractionation, the most active fractions (#28–36) from V. vinifera grape seed showed a 3.5- to 5.9-fold increase in the modulus of elasticity. The baseline results ranged from 3.4 to 5.9 MPa. After biomodification, the modulus of elasticity values increased to 15.1–27.3 MPa. In addition, four of these active fractions (#28–31) exhibited the lowest biodegradation ratio between 0.2 and 1.8%. Conclusion: Although the individual fractions did not exhibit as high activity levels as observed for V. vinifera crude seed extract, the observed potencies of the active fractions will help to understand the effect of the degree of oligomerization, the amount and the complexity of PA composition. Funding: NIH/NIDCR DE021040 IRB/ACCC protocol: 2009-0198.
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of variance and Tukey honestly significant difference (HSD) test were performed to compare the SBS of the groups. The chi-square test was used to evaluate differences in ARI scores between the groups. Results: A significant difference among the shear bond strength values between different groups was found (P < 0.000). All experimental groups showed an increase in the SBS values when the enamel was treated with prophylactic pastes after acid-etching. The shear bond values between the control and experimental groups before or after acid-etching were not significantly different from each other (P > 0.05), except in group 2a and the control (P = 0.034), groups 1a and 3b (P = 0.001), and between groups 2a and 3a (P < 0.000). However within the same paste, there was statistical difference between groups 2a and 2b (P = 0.024). More composite remained on the teeth when the prophylactic pastes were applied after acid-etch, which was indicated by a shift in ARI scores from 0 and 1 before acid-etching to 2 and 3 after acid-etching. Conclusion: The treatment with different pastes did not influence SBS when compared within the before or after etching groups. However, the application of the pastes after acid etching resulted in significantly higher SBS than when pastes were applied before etching. http://dx.doi.org/10.1016/j.dental.2013.08.134 134 EDC stabilize the adhesive interface over time V. Angeloni 1,2,∗ , A. Mazzoni 1 , A. Frassetto 1 , M. Cadenaro 1 , M. Falconi 2 , L. Manzoli 2 , D.H. Pashley 3 , L. Breschi 1 1
http://dx.doi.org/10.1016/j.dental.2013.08.133 133 Effects of different prophylactic pastes on the shear bond strength of orthodontic brackets A.M. Aljobair ∗ , H.M. Alkawari King Saud University, Riyadh, Saudi Arabia Purpose: To evaluate in vitro the effect of enamel treatment with prophylactic pastes containing casein phosphopeptideamorphous calcium phosphate (CPP-ACP) and/or fluoride on the bracket shear bond strength (SBS) when applied before or after acid-etching. Methods and materials: One hundred and twelve human premolars were randomly divided into the following groups (16 teeth/group): Group C: served as control, and no pretreatment was performed on enamel. Groups 1a, 2a, and 3a: enamel was pre-treated with CPP-ACP (MI paste), fluoride-containing CPP-ACP paste (MI Paste Plus), and 5% sodium fluoride (Fluoraphat Varnish) respectively before acid-etching. Groups 1b, 2b and 3b: enamel was treated with the same pastes after acid-etching. The brackets were bonded and the teeth were thermocycled at 5 ± 2 ◦ C to 55 ± 2 ◦ C for 1000 cycles. All bonded teeth were tested for SBS. After debonding, the bracket bases and the enamel surfaces were examined to assess any adhesive remaining using Adhesive Remnant Index (ARI). Analysis
University of Trieste, Trieste, Italy University of Bologna, Bologna, Italy 3 Georgia Health Sciences University, Augusta, GA, USA 2
Purpose: Previous studies supported the use of collagen cross-linkers to improve mechanical strength of the collagen network and resistance to enzymatic degradation due to MMPs inhibition. Among these solutions, the use of 1-ethyl-3(3-dimethylaminopropyl) carbodiimide HCl (EDC) was recently investigated showing its effectiveness in the preservation of the collagen degradation over time, thus improving bond durability. The aim of the study was to evaluate the effects of 0.3 M EDC-containing conditioner on the adhesive interface stability created by a 2-step etch-and-rinse adhesive system. Methods and materials: Twenty-four middle/deep dentin surfaces were etched with 35% phosphoric acid for 15 s, rinsed and blot dried. Specimens were then assigned to the following treatments. Group 1: dentin was pretreated with 0.3M EDC conditioner for 1 min, then bonded with XP Bond (Dentsply); Group 2: XP Bond was applied on untreated etched dentin (control group). In both groups XB Bond was generously applied with a microbrush for 20 s, according to manufacturer’s instructions, and light-cured for 20 s after solvent evaporation. Composite buildups were made using Filtek Z250 (3M ESPE). The bonded teeth were serially cut for microtensile bond strength test (TBS) in accordance with the non-trimming technique and stressed to failure at a
LH-20 and high-resolution fractions (#1–40) were produced. Firstly, these fractions were combined into 6 fractions (low resolution) according to a thin layer chromatography profile. To assess the fractions (6.5%, w/v relative concentration), dentin beams (1.7 mm × 0.5 mm × 6 mm) were prepared from extracted human molars. Beams were fully demineralized using 10% phosphoric acid solution for 5 h and divided into groups (n = 5). The modulus of elasticity was assessed at baseline and after 1 h in their respective solutions. A 3-point bending test was employed at 3% strain, and data (MPa) were calculated as fold increase. Afterwards, the most active solutions were selected and the corresponding individual high-resolution fractions were tested (#19–40). Beams were treated as described before and the modulus of elasticity was evaluated. The same specimens were used to assess biodegradation using bacterial collagenase (100 g/ml Clostridium histolyticum) for 24 h at 37 ◦ C, and data dry mass loss was calculated. Results: Considering the high-resolution fractionation, the most active fractions (#28–36) from V. vinifera grape seed showed a 3.5- to 5.9-fold increase in the modulus of elasticity. The baseline results ranged from 3.4 to 5.9 MPa. After biomodification, the modulus of elasticity values increased to 15.1–27.3 MPa. In addition, four of these active fractions (#28–31) exhibited the lowest biodegradation ratio between 0.2 and 1.8%. Conclusion: Although the individual fractions did not exhibit as high activity levels as observed for V. vinifera crude seed extract, the observed potencies of the active fractions will help to understand the effect of the degree of oligomerization, the amount and the complexity of PA composition. Funding: NIH/NIDCR DE021040 IRB/ACCC protocol: 2009-0198.
e65
of variance and Tukey honestly significant difference (HSD) test were performed to compare the SBS of the groups. The chi-square test was used to evaluate differences in ARI scores between the groups. Results: A significant difference among the shear bond strength values between different groups was found (P < 0.000). All experimental groups showed an increase in the SBS values when the enamel was treated with prophylactic pastes after acid-etching. The shear bond values between the control and experimental groups before or after acid-etching were not significantly different from each other (P > 0.05), except in group 2a and the control (P = 0.034), groups 1a and 3b (P = 0.001), and between groups 2a and 3a (P < 0.000). However within the same paste, there was statistical difference between groups 2a and 2b (P = 0.024). More composite remained on the teeth when the prophylactic pastes were applied after acid-etch, which was indicated by a shift in ARI scores from 0 and 1 before acid-etching to 2 and 3 after acid-etching. Conclusion: The treatment with different pastes did not influence SBS when compared within the before or after etching groups. However, the application of the pastes after acid etching resulted in significantly higher SBS than when pastes were applied before etching. http://dx.doi.org/10.1016/j.dental.2013.08.134 134 EDC stabilize the adhesive interface over time V. Angeloni 1,2,∗ , A. Mazzoni 1 , A. Frassetto 1 , M. Cadenaro 1 , M. Falconi 2 , L. Manzoli 2 , D.H. Pashley 3 , L. Breschi 1 1
http://dx.doi.org/10.1016/j.dental.2013.08.133 133 Effects of different prophylactic pastes on the shear bond strength of orthodontic brackets A.M. Aljobair ∗ , H.M. Alkawari King Saud University, Riyadh, Saudi Arabia Purpose: To evaluate in vitro the effect of enamel treatment with prophylactic pastes containing casein phosphopeptideamorphous calcium phosphate (CPP-ACP) and/or fluoride on the bracket shear bond strength (SBS) when applied before or after acid-etching. Methods and materials: One hundred and twelve human premolars were randomly divided into the following groups (16 teeth/group): Group C: served as control, and no pretreatment was performed on enamel. Groups 1a, 2a, and 3a: enamel was pre-treated with CPP-ACP (MI paste), fluoride-containing CPP-ACP paste (MI Paste Plus), and 5% sodium fluoride (Fluoraphat Varnish) respectively before acid-etching. Groups 1b, 2b and 3b: enamel was treated with the same pastes after acid-etching. The brackets were bonded and the teeth were thermocycled at 5 ± 2 ◦ C to 55 ± 2 ◦ C for 1000 cycles. All bonded teeth were tested for SBS. After debonding, the bracket bases and the enamel surfaces were examined to assess any adhesive remaining using Adhesive Remnant Index (ARI). Analysis
University of Trieste, Trieste, Italy University of Bologna, Bologna, Italy 3 Georgia Health Sciences University, Augusta, GA, USA 2
Purpose: Previous studies supported the use of collagen cross-linkers to improve mechanical strength of the collagen network and resistance to enzymatic degradation due to MMPs inhibition. Among these solutions, the use of 1-ethyl-3(3-dimethylaminopropyl) carbodiimide HCl (EDC) was recently investigated showing its effectiveness in the preservation of the collagen degradation over time, thus improving bond durability. The aim of the study was to evaluate the effects of 0.3 M EDC-containing conditioner on the adhesive interface stability created by a 2-step etch-and-rinse adhesive system. Methods and materials: Twenty-four middle/deep dentin surfaces were etched with 35% phosphoric acid for 15 s, rinsed and blot dried. Specimens were then assigned to the following treatments. Group 1: dentin was pretreated with 0.3M EDC conditioner for 1 min, then bonded with XP Bond (Dentsply); Group 2: XP Bond was applied on untreated etched dentin (control group). In both groups XB Bond was generously applied with a microbrush for 20 s, according to manufacturer’s instructions, and light-cured for 20 s after solvent evaporation. Composite buildups were made using Filtek Z250 (3M ESPE). The bonded teeth were serially cut for microtensile bond strength test (TBS) in accordance with the non-trimming technique and stressed to failure at a