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OBJECTIVES: The aim of this in vitro study was to compare the microleakage of direct composite veneer restorations prepared by a conventional dental bur or Er,Cr:YSGG (erbium, chromium doped yttrium scandium gallium garnet) laser and etched with different procedures. METHODS: Fifty maxillary incisor teeth prepared for direct veneers with gingival margins in dentin and incisal margins in enamel were randomly divided into five groups (n = 10): group 1 (control), prepared with diamond bur and etched with phosphoric acid; group 2, prepared with diamond bur and etched with Er,Cr:YSGG laser (Waterlase MD/Biolase); group 3, prepared with laser and not etched; group 4, prepared with laser and etched with phosphoric acid; and group 5, prepared and etched with laser. After the application of the etch and rinse adhesive system (Prime & Bond NT/Dentsply), teeth were restored with the nano ceramic restorative material (Ceram X Duo/Dentsply), subjected to thermocycling and immersed in 0.5% basic fuchsin dye for 24 h. The teeth were sectioned longitudinally and dye penetration was evaluated by a binocular stereomicroscope equipped with a measuring device. Data were analyzed by Kruskal-Wallis and Wilcoxon signed ranks tests. The level of significance was set at p = 0.05. RESULTS: Significant differences were observed in enamel of the five groups (p < 0.05). Minimal microleakage was observed in groups 1 and 3. The highest microleakage was evaluated in group 5 (p < 0.05). No significant differences were found among the five groups in dentin (p > 0.05). No differences were recorded between the microleakage values in enamel and dentin within each group and this was valid for all groups (p > 0.05). CONCLUSIONS: The results confirmed that enamel and dentin surfaces prepared with Er,Cr:YSGG laser for direct composite veneer restorations may provide comparable sealing.

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The aim of this study was to evaluate the microleakage of all-in-one self-etch adhesives and their respective nanocomposites in class V cavities prepared by erbium:yttrium-aluminum-garnet (Er:YAG) laser and bur. Class V cavities were prepared on both buccal and lingual surfaces of 72 premolars by Er:YAG laser or bur and divided into six groups (n = 24). The occlusal margins were enamel and the cervical margins were cementum. The groups were as follows: group 1 Er:YAG laser preparation (E) + Xeno V (X) + CeramX (C); group 2 bur preparation (B) + X + C; group 3 E + AdheSE One (A) + Tetric EvoCeram (T); group 4 B + A + T; group 5 E + Clearfil S3 Bond (CSB) + Clearfil Majesty Esthetic (CME); group 6 B + CSB + CME. All teeth were stored in distilled water at 37 degrees C for 24 h, then thermocycled 500 times (5-55 degrees C). Ten teeth from each group were chosen for the microleakage investigation and two teeth for the scanning electron microscopy (SEM) evaluation. The teeth that were prepared for the microleakage test were immersed in 0.5% basic fuchsin dye for 24 h. After immersion, 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). Bur-prepared cavities presented less microleakage in all groups for enamel (P < 0.05); however, in cervical margins, there were no differences between laser-prepared and bur-prepared cavities in the Xeno V + CeramX and AdheSE One + Tetric EvoCeram groups (P > 0.05). SEM observations of restorative material-dentin interfaces seemed to correspond with those of the microleakage test. Microleakage at the cervical interfaces was greater than that at the occlusal interfaces. Er:YAG laser-prepared class V cavities yielded more microleakage in occlusal margins with all-in-one self-etch adhesives and the respective manufacturer's nanocomposites.

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The purpose of this study was to investigate shear bond strength (SBS) between a light-curing nano-ionomer restorative and enamel or dentin after acid etching, after erbium:yttrium-aluminum-garnet (Er:YAG) laser etching, or after combined treatment. Forty third molars were selected, the crowns were sectioned, and 80 tooth slabs were obtained. The specimens were assigned to two groups, which were divided into four subgroups(n = 10). Group 1 [enamel (e)], treated with 37% phosphoric acid (A) + Ketac nano-primer (K); group 2 [dentin (d)], (A) + (K); group 3(e), Er:YAG laser etching (L) + (A) + (K); group 4(d), (L) + (A) + (K); group 5(e), (L) + (K); group 6(d), (L) + (K); group 7(e), (K); group 8(d), (K). The SBS of the specimens was measured with a universal test machine (1 mm/min). Data were analyzed by independent samples t-test, one-way analysis of variance (ANOVA) and a post-hoc Duncan test (p < 0.05). No difference was determined between groups 3 and 5 (p > 0.05). Group 7 exhibited higher SBS values than those of groups 3 and 5 (p < 0.05). Group 1 showed higher SBSs than those of groups 3, 5 and 7 (p < 0.05). There was no significant difference between groups 4 and 6 (p > 0.05). No difference was observed between groups 2 and 4 (p > 0.05). However, group 2 presented higher SBSs than did group 6 (p < 0.05). Group 8 exhibited the highest SBS values when compared with groups 2, 4 and 6 (p < 0.05). Er:YAG laser adversely affected the adhesion of the light-curing nano-ionomer restorative to both enamel and dentin.

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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.

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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.

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