Nuray Attar

Shear Bond Strength of Orthodontic Brackets Bonded using Conventional vs One and Two Step Self-etching/adhesive Systems

OBJECTIVE To assess and compare the effects of one- and two-step self-etching primer and adhesive with conventional acid-etching and bonding system on the shear bond strength of orthodontic brackets. MATERIALS AND METHODS The one-step self-etching primer and adhesive used was Clearfil tri-S bond, the two-step fluoride-releasing antibacterial self-etching primer and adhesive was Clearfil Protect Bond, and the fluoride-releasing conventional acid-etching and bonding system was Kurasper F Bond. Brackets were bonded to defect-free human premolars (n = 14 per group) according to each manufacturers recommendations by using light-cured bracket adhesive Kurasper F Paste with a light-emitting diode of a light-curing unit. The specimens were stored in deionized water at 37 degrees C for 48 hours and then tested in shear with a universal testing machine at a crosshead speed of 5 mm/min until the brackets debonded. The mode of failure of the brackets was determined by a modified adhesive remnant index. RESULTS Mean shear bond strength values were 9.00 MPa for Kurasper F Bond, 9.55 MPa for Clearfil Protect Bond, and 9.48 MPa for Clearfil tri-S Bond. One-way analysis of variance detected no statistically significant difference among groups (P = .98, P > .05). The predominant failure for the three groups was at the bracket-adhesive interface leaving less than 25% of the adhesive on the bracket base. CONCLUSIONS One-step self-etching adhesive and two-step fluoride-releasing antibacterial self-etching adhesive have sufficient mechanical properties for the bonding of orthodontic brackets.

Microleakage of Class V Cavities with Different Adhesive Systems Prepared by a Diamond Instrument and Different Parameters of Er:YAG Laser Irradiation

OBJECTIVE The aim of this study was to evaluate the microleakage of composite resin restorations using two different dentine adhesive systems prepared with a diamond instrument and different parameters of Er:YAG laser irradiation. BACKGROUND DATA Information on this topic with regard to preparing class V cavities with different parameters of Er:YAG laser irradiation and adhesive systems is scarce. MATERIALS AND METHODS Two hundred class V cavities were assigned to ten groups (n = 20 each): group 1: Er:YAG laser (5 Hz, 600 mJ) + phosphoric acid (PA) + Adper Single Bond 2 (ASB2); group 2: Er:YAG laser (10 Hz, 300 mJ) + PA + ASB2; group 3: Er:YAG laser (15 Hz, 200 mJ) + PA + ASB2; group 4: Er:YAG laser (20 Hz, 150 mJ) + PA + ASB2; group 5: diamond instrument + PA + ASB2; group 6: Er:YAG laser (5 Hz, 600 mJ) + Adper Prompt L-Pop (APLP); group 7: Er:YAG laser (10 Hz, 300 mJ) + APLP; group 8: Er:YAG laser (15 Hz, 200 mJ) + APLP; group 9: Er:YAG laser (20 Hz, 150 mJ) + APLP; and group 10: diamond instrument + APLP. Cavities were restored with a nanofill composite (Filtek Supreme XT Body). After thermocycling, the specimens were stained with 0.5% aqueous basic fuchsin dye and sectioned bucco-lingually. Dye penetration was then scored. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction. The Wilcoxon signed ranks test was used to compare occlusal and gingival scores. RESULTS Leakage was seen in all groups at both the occlusal and gingival margins. The Kruskal-Wallis test showed statistically significant differences among the 10 groups (p < 0.001). The gingival margins had more microleakage than the occlusal margins (p < 0.001). Pairwise analysis by the Mann-Whitney U test showed that statistically significant differences (p < 0.05) in microleakage were found between groups 3 and 5 (3 > 5), 5 and 7 (7 > 5), and 7 and 8 (7 > 8) at the gingival margin, and between groups 3 and 6 (6 > 3), 3 and 7 (7 > 3), 4 and 6 (6 > 4), and 4 and 7 (7 > 4) at the occlusal margin. CONCLUSION We concluded that for all groups, microleakage values were higher at the gingival margins. The use of the Er:YAG laser for cavity preparation with different parameters and different dentine adhesive systems influenced the marginal sealing of composite resin restorations.

Leakage Pathway of Different Nano-Restorative Materials in Class V Cavities Prepared by Er:YAG Laser and Bur Preparation

OBJECTIVE The aim of this study was to evaluate the microleakage of different nano-restorative materials in Class V cavities prepared by Er:YAG laser and bur preparation. MATERIALS AND METHODS Class V cavities were prepared on the buccal and lingual surfaces of 72 premolars by Er:YAG laser or bur. The occlusal margins were in enamel and the cervical margins were in cementum. Teeth were randomly assigned to six groups of 12 teeth (n = 24 cavities) each as follows: Group 1, Er:YAG laser preparation (E)+Ketac N100 (K); Group 2, bur preparation (B)+K; Group 3, E+Adper Prompt L-Pop (A)+Filtek Supreme XT Flow (FSF); Group 4, B+A+FSF; Group 5, E+A+Filtek Supreme XT (FS); Group 6, B+A+FS. All teeth were thermocycled 500 times. Ten teeth from each group were chosen for the microleakage investigation and two teeth for the scanning electron microscope evaluation. Teeth prepared for the microleakage test were immersed in 0.5% basic fuchsin dye for 24 h. Afterwards, the teeth were sectioned and observed under a stereomicroscope for dye penetration. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests (p < 0.05). RESULTS There were significant differences between occlusal and cervical regions for all groups (p < 0.05) except for Group 1. Bur-prepared cavities showed less microleakage in all groups for enamel (p < 0.05); however, in cementum there were no significant differences between the bur- and laser-prepared cavities in nano-glass ionomer and flowable composite groups (p > 0.05). CONCLUSION It may be concluded that the cavities prepared by Er:YAG laser showed higher degree of microleakage than those conventionally prepared by bur, regardless of the restorative material at enamel margins.

Effects of two different bleaching agents on surface roughness and microhardness of different novel nano-restorative materials

Objectives: The aim of this study was to evaluate the effects of 15% hydrogen peroxide (Illuminé Office) and 16% carbamide peroxide (VivaStyle) on the surface roughness and hardness of nano-restoratives. Materials and Methods: A total of 30 specimens of each material were fabricated using Clearfil Majesty Esthetic (Group1), Tetric EvoFlow (Group2) and Ketac N100 (Group3). Each group were divided into 3 subgroups and treated as follows: Group 1a, 2a, 3a was treated with Illuminé Office, Group 1b, 2b, 3b was treated with VivaStyle, Group 1c, 2c, 3c was stored in distilled water at 37°C for two weeks (control). Surface roughness and microhardness tests were performed. Results: There were no significant differences in terms of roughness and microhardness among Clearfil Majesty Esthetic and Tetric EvoFlow groups, seperately (P > 0.05). Illuminé Office increased the roughness and decreased the microhardness of Ketac N100 (P< 0.05). Conclusion: Bleaching may affect the roughness and microhardness of nano-restoratives depending on material and bleaching system.