The effect of an erbium, chromium: yttrium-scandium-gallium-garnet laser on the microleakage and bond strength of silorane and micro-hybrid composite restorations

Effect of different types of adhesive systems on the bond strength and marginal integrity of composite restorations in cavities prepared with the erbium laser-a systematic review

There are inconclusive results regarding etching and bonding protocol to achieve optimal bond strength and marginal integrity of adhesive composite resin restorations in erbium laser prepared cavities. This systematic review aimed to consider which adhesive system protocol may be optimal in achieving the bond strength and marginal integrity in erbium laser-prepared cavities, comparable to that obtained with conventional method of cavity preparation. This review was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement with literature search based on all publications during the period January1, 2000-October 10, 2020, in three databases: MEDLINE, Google Scholar and ScienceDirect. The necessary information was extracted by two independent authors. The search resulted in 139 articles from all databases, and a total of thirty-one articles met the inclusion criteria. The results indicated that the selection of adhesives depending on their pH and composition and the laser pulse duration and pulse energy used plays an important role in predicting the adhesion and marginal integrity. The 10-MDP containing moderate self-etch adhesives has demonstrated predictable outcomes. Longer pulse durations used for cavity preparations may indicate the use of etch-and-rinse (EnR) or moderate self-etch adhesives (SEA) to allow better resin infiltration in deep craters formed due to laser irradiation. However, further studies with more standardizations in relation to adhesives and laser parameters are needed.

Influence of gamma radiation on microshear bond strength and nanoleakage of nanofilled restoratives in Er, Cr:YSGG laser-prepared cavities

Objective:

To evaluate the effect of gamma radiation on microshear bond strength and nanoleakage of nanofilled restoratives in laser-prepared cavities.

Materials and Methods:

Twenty-eight flat buccal dentin surfaces were prepared for microshear bond strength test. Er, Cr:YSGG laser was used to prepare another 28 Class V cavities on the buccal surfaces of the molars. All teeth were divided into four groups; 1^st group: Application of Filtek Z350 nanocomposite material, 2^nd group: As the 1^st group and then exposure to gamma radiation, 3^rd group: Application of Ketac N100 nanoglass ionomer, and the 4^th group: As the 3^rd group and then gamma irradiated. The bond strength test was performed after storage in artificial saliva for 24 h. For the nanoleakage test, teeth were submerged in a solution of ammoniacal silver nitrate, sectioned, and then examined under a scanning electron microscope. The collected data were statistically analyzed.

Results:

Nanocomposite showed higher bond strength values than nanoglass ionomer. Despite the fact that gamma radiation did not decrease nanocomposite bond strength, it decreased nanoglass ionomer bond strength. Nanoglass ionomer-restored cavities showed higher silver ion penetration than nanocomposite in both control and gamma-irradiated groups.

Conclusion:

Gamma radiation has no effect on bond strength and nanoleakage of nanocomposite so that it can be placed before radiotherapy. On the other hand, the bond strength of nanoglass ionomer was adversely affected by gamma radiation.

Comparison of marginal microleakage of flowable composite restorations in primary canine teeth prepared with high-speed diamond bur, Er:YAG laser and Er,Cr:YSGG laser

Background and Objectives

Adhesive restorations have become highly popular in pediatric dentistry, and novel methods of cavity preparation with minimal patient discomfort including Er:YAG and Er,Cr:YSGG laser preparations have greatly advanced. This study aimed to compare the microleakage of composite restorations of class V cavities prepared in primary canine teeth with high-speed bur and Er:YAG and Er,Cr:YSGG lasers.

Materials and Methods

This in vitro study was conducted on 30 class V cavities prepared on the buccal surfaces of primary canine teeth in three groups (n = 10) of bur preparation, Er:YAG laser and Er,Cr:YSGG laser. The cavities were etched, bonded and restored with Grandio flowable composite according to the manufacturer's instructions. After thermocycling, the teeth were immersed in 1% methylene blue dye for 24 hours to detect microleakage. The teeth were evaluated under a stereomicroscope at ×32 magnification to assess the depth of penetration of methylene blue. The data were analyzed using SPSS version 19 and non-parametric Kruskal-Wallis and Mann Whitney tests.

Results

Non-parametric Kruskal-Wallis test showed no significant difference in dye penetration among the three groups (P > 0.05). Pairwise comparisons of occlusal and gingival margins by nonparametric Mann Whitney test revealed no significant difference in microleakage either (P > 0.05).

Conclusion

Use of Er:YAG and Er,Cr:YSGG lasers can decrease microleakage to the level of bur preparation. Bur and laser cavity preparations are not significantly different in terms of microleakage at the enamel or dentin margins. Thus, considering the advantages of laser, it may serve as a suitable alternative to bur preparation in pediatric dentistry.

In vitro microleakage of class v composite restorations prepared by Er,Cr:YSGG laser and carbide bur

Background: The aim of this in vitro study was to compare the degree of microleakage on enamel and dentin margins of class V cavities prepared with either a high-speed drill or an Er,Cr:YSGG laser (2780 nm) and to associate their use with a beveling method for the margin. Method and Materials: Sixty bovine incisors were randomly distributed into three groups. Group 1 (G1) cavities were laser prepared and bur beveled, group 2 (G2) cavities were bur prepared and beveled, while cavities of group 3 (G3) were laser prepared and beveled. Cavities were restored with selective enamel etching, using the same bonding agent and nano-hybrid resin composite for all groups. After thermocycling, microleakage was assessed using a methylene blue dye penetration method. Results: Statistical analysis (Mann-Whitney, Kruskal-Wallis and post-hoc Dunn’s multiple comparison tests) demonstrated significantly higher microleakage for dentin compared to enamel margins in G1. Enamel margin microleakage was found to be significantly higher at G3 compared to G1 (p=0.032) and G2 (p=0.001), while no significant differences were found between G1 and G2 (p=0.850). Regarding dentin margins, G2 group performed significantly better than G1 and G3 (p<<0.001), while there was no significant difference among G1 and G3 scores (p=1.000). Conclusions: The conventional cavity preparation method seems to perform better in terms of microleakage than the Er,Cr;YSGG laser. Laser-prepared cavities could perform better in terms of microleakage if an additional step of enamel bur-beveling is performed prior to restoration.