Comparative study between laser and conventional techniques for class V cavity preparation in gamma-irradiated teeth (in vitro study).

OBJECTIVE: The purpose of this study was to compare laser with conventional techniques in class V cavity preparation in gamma-irradiated teeth. METHODS: Forty extracted human teeth with no carious lesions were used for this study and were divided into two main groups: Group I (n = 20) was not subjected to gamma radiation (control) and Group II (n=20) was subjected to gamma radiation of 60 Gray. Standard class V preparation was performed in buccal and lingual sides of each tooth in both groups. Buccal surfaces were prepared by the Er,Cr:YSGG laser (Waterlase iPlus) 2780 nm, using the gold handpiece with MZ10 Tip in non-contact and the "H" mode, following parameters of cavity preparation - power 6 W, frequency 50 Hz, 90% water and 70% air, then shifting to surface treatment laser parameters - power 4.5 W, frequency 50 Hz, 80% water and 50% air. Lingual surfaces were prepared by the conventional high-speed turbine using round diamond bur. Teeth were then sectioned mesio-distally, resulting in 80 specimens: 40 of which were buccal laser-treated (20 control and 20 gamma-irradiated specimens) and 40 were lingual conventional high-speed bur specimens (20 control and 20 gamma-irradiated specimens). RESULTS: Microleakage analysis revealed higher scores in both gamma groups compared with control groups. Chi-square test revealed no significant difference between both control groups and gamma groups (p=1, 0.819, respectively). A significant difference was revealed between all 4 groups (p=0.00018). CONCLUSION: Both laser and conventional high-speed turbine bur show good bond strength in control (non-gamma) group, while microleakage is evident in gamma group, indicating that gamma radiation had a dramatic negative effect on the bond strength in both laser and bur-treated teeth.

Comparative study between laser and conventional techniques for class V cavity preparation in gamma-irradiated teeth (in vitro study)

Abstract Objective: The purpose of this study was to compare laser with conventional techniques in class V cavity preparation in gamma-irradiated teeth. Methods: Forty extracted human teeth with no carious lesions were used for this study and were divided into two main groups: Group I (n = 20) was not subjected to gamma radiation (control) and Group II (n=20) was subjected to gamma radiation of 60 Gray. Standard class V preparation was performed in buccal and lingual sides of each tooth in both groups. Buccal surfaces were prepared by the Er,Cr:YSGG laser (Waterlase iPlus) 2780 nm, using the gold handpiece with MZ10 Tip in non-contact and the "H" mode, following parameters of cavity preparation - power 6 W, frequency 50 Hz, 90% water and 70% air, then shifting to surface treatment laser parameters - power 4.5 W, frequency 50 Hz, 80% water and 50% air. Lingual surfaces were prepared by the conventional high-speed turbine using round diamond bur. Teeth were then sectioned mesio-distally, resulting in 80 specimens: 40 of which were buccal laser-treated (20 control and 20 gamma-irradiated specimens) and 40 were lingual conventional high-speed bur specimens (20 control and 20 gamma-irradiated specimens). Results: Microleakage analysis revealed higher scores in both gamma groups compared with control groups. Chi-square test revealed no significant difference between both control groups and gamma groups (p=1, 0.819, respectively). A significant difference was revealed between all 4 groups (p=0.00018). Conclusion: Both laser and conventional high-speed turbine bur show good bond strength in control (non-gamma) group, while microleakage is evident in gamma group, indicating that gamma radiation had a dramatic negative effect on the bond strength in both laser and bur-treated teeth.

Effect of the erbium:yttrium-aluminum-garnet laser or diamond bur cavity preparation on the marginal microleakage of class V cavities restored with different adhesives and composite systems.

The aim of this in vitro study was to compare the microleakage of Er:YAG laser and diamond bur on different bonding systems in class V restorations. Class V cavities were prepared with Er:YAG laser or diamond bur on 80 intact human molars. Teeth were randomly distributed into ten groups and cavities were restored with CeramX duo (DENTSPLY) or Filtek Silorane (3M/ESPE) using different bonding materials (One Coat 7.0 (Coltène), XP Bond (DENTSPLY), Clearfil Protect Bond (Kuraray), AdperSE (3M/ESPE), and Silorane System Adhesive (3M/ESPE). All specimens were subjected to thermocycling and load cycling. After being immersed in silver nitrate dye, the specimens were sectioned. Microleakage was evaluated by stereomicroscope and SEM. Data were statistically analyzed by one-way ANOVA, Kruskal-Wallis, and Mann-Whitney tests. Statistically differences were found between groups (p > 0.05) and cavities prepared with the Er:YAG laser showed higher microleakage than diamond bur. The microleakage of different bonding systems was influenced by the choice of diamond bur or Er:YAG laser for class V composite cavity preparation.

Comparison of the effects of Er,Cr:YSGG laser and different cavity disinfection agents on microleakage of current adhesives.

The aim of this study was to compare the effect of the Er,Cr:YSGG laser and different cavity disinfection agents on microleakage of an etch-and-rinse and a self-etch adhesive. Class V preparations were completed on the buccal and lingual surfaces of 30 extracted noncarious human molars. The occlusal margin was placed on enamel and the gingival margin on dentin. Preparations were randomly divided into five experimental groups (n = 12); (1) 2% chlorhexidine gluconate (CHX), (2) propolis, (3) ozone, (4) Er,Cr:YSGG laser, and (5) control (no treatment). Each group was divided into two subgroups according to the adhesive system: etch-and-rinse (Adper Single Bond 2), and a self-etch adhesive (All-Bond SE). The preparations were bulk-filled with a resin composite (Arabesk). After storage in distilled water for 24 h the restored teeth were subjected to thermocycling (1,000 cycles; 5-55°C). All specimens were immersed in 0.5% basic fuchsin solution for 24 h and sectioned longitudinally through the centre of the restorations and examined under a stereomicroscope at ×25 magnification. The data were analysed using the Kruskal-Wallis and Mann-Whitney U-tests. No difference was observed between the groups either on enamel or dentin when the etch-and-rinse adhesive was used (p > 0.05). In the self-etch adhesive groups, a significant difference was found only between the laser group and the CHX group on enamel and between the propolis group and the control group on dentin (p < 0.05). Comparing the etch-and-rinse and self-etch adhesives within each group, no differences were found on dentin (p > 0.05). On enamel, a statistically significant difference was found only in the CHX group (p < 0.05). There were no differences in microleakage with the laser and the different cavity disinfectant applications when used with etch-and-rinse adhesive. In the self-etch group there were differences in microleakage depending on the disinfection agent used.

Nd:YAG laser effects on the microleakage of composite resin restorations.

OBJECTIVE: This study evaluated microleakage of composite restorations submitted to marginal treatment with Nd:YAG laser and surface sealant. BACKGROUND DATA: Previous studies have demonstrated that Nd:YAG-lased enamel melted and became recrystallized with a morphologic appearance similar to lava, and has been used clinically in the sealing of enamel pits and fissures. METHODS: Class V cavities in enamel of human premolars were restored with composite resin (Z100, 3M) and randomly divided in six groups: G1, control; G2, surface sealant marginal treatment; G3 to G6, were treated with pulsed Nd:YAG laser (1.064 microm) marginal treatment, contact fiberoptic (300 microm), air cooling, for 30 seconds, powers of 1.2-2 W, repetition rates of 20-30 Hz, energies of 40-100 mJ. Teeth were impermeabilized, immersed in a rhodamine dye, sectioned, and evaluated under stereomicroscope microscopy with scores. RESULTS: There were significant differences between marginal treatments; there were no differences between groups 1, 2, and 4, and 3,5, and 6; lower values of microleakage were at groups 3, 5, and 6 (Kruskal-Wallis,p = 0.05). CONCLUSION: Nd:YAG laser showed improved marginal sealing and decreased microleakage of composite resins restorations.