A comparative study of microleakage through enamel and cementum after laser Er:YAG instrumentation in class V cavity obturations, using scanning electron microscopy

Microleakage in Class V cavities with self-etching adhesive system and conventional rotatory or laser Er,Cr:YSGG

OBJECTIVE

To analyse microleakage in Class V cavity preparation with Er;Cr:YSGG at different parameters using a self-etching adhesive system.

BACKGROUND

Several studies reported microleakage around composite restorations when cavity preparation is done or treated by Er;Cr:YSGG laser. We want to compare different energy densities in order to obtain the best parameters, when using a self-etching adhesive system.

METHODS

A class V preparations was performed in 120 samples of human teeth were divided in 3 groups: (1) Preparation using the burr. (2) Er;Cr:YSGG laser preparation with high energy 4W, 30 Hz, 50% Water 50% Air and (3) Er;Cr:YSGG laser preparation lower energy 1.5 W, 30 Hz, 30% Water 30% Air. All the samples were restored with self-etching adhesive system and hybrid composite. Thermocycling (5000 cycles) and immersed in 0.5% fuchsin. The restorations were sectioned and evaluated the microleakage with a stereomicroscope.

RESULTS

Lower energy laser used for preparation showed significant differences in enamel and dentin. To group 3, the microleakage in the enamel was less, whilst the group 1, treated with the turbine, showed less microleakage at dentin level. Group 2 showed the highest microleakage at dentin/cement level.

CONCLUSION

Burr preparation gives the lowest microleakage at cement/dentin level, whilst Er;Cr:YSGG laser at lower power has the low energy obtains lowest microleakage at enamel. On the contrary high-energy settings produce inferior results in terms of microleakage.

Microleakage of class V glass ionomer restorations after conventional and Er:YAG laser preparation

OBJECTIVE

The aim of this study was to investigate the microleakage in class V cavities following Er:YAG laser or conventional preparation restored with two conventional glass ionomer cements (cGIC) and to evaluate the effect of conditioning on laser-prepared surfaces.

BACKGROUND DATA

Information on this topic related to cGIC is scarce.

METHODS

Sixty class V cavities were assigned to six groups: I and IV were Er:YAG-lased, II and V Er:YAG-lased and conditioned, and III and VI conventionally prepared and conditioned. Groups I, II, and III, were restored with Ketac Fil Plus Applicap; groups IV, V, and VI were restored with Fuji IX GP Capsule. Then, teeth were stored in distilled water (37 degrees C, 24 h), thermal cycled 1500 times (5-55 degrees C), placed in a 2% aqueous solution of methylene blue (37 degrees C, 24 h), embedded in acrylic resin, sectioned oro-facially, and analyzed for leakage.

RESULTS

Statistically significant differences between occlusal and cervical regions were observed (p < 0.05). Group III showed significantly more microleakage at the occlusal margin compared to group II (p = 0.022). Group V showed significantly more microleakage at the gingival margin than group VI (p = 0.022). Leakage on the occlusal margins was significantly higher in group III than in group VI (p = 0.038). Scanning electron microscopy indicated that conditioning of laser-prepared dentin with Ketac conditioner partially closed the tubules' orifices, whereas the use of GC conditioner completely obliterated the tubules.

CONCLUSION

The application of Ketac Fil Plus to laser-prepared enamel and dentin resulted in a better and more reproducible seal compared to conventionally prepared tooth surfaces. When using the more viscous Fuji IX application, Er:YAG lasing did not improve marginal adaptation.

Er:YAG laser cavity preparation and composite resin bonding with a single-component adhesive system: relationship between shear bond strength and microleakage

BACKGROUND AND OBJECTIVES

The purpose of this study was to assess the performances of a single-component adhesive system when an Er:YAG laser was used to prepare cavities.

STUDY DESIGN/MATERIALS AND METHODS

Shear bond strength tests were performed on composite rods bonded with a single-component adhesive system to dentin surfaces prepared using either bur+acid, Er:YAG laser (fluence = 44 J/cm2), or Er:YAG laser+acid. Class V cavities were prepared differently according to the molar surface: buccal surfaces were prepared using a diamond bur, and lingual surfaces using the Er:YAG laser. In group 1, cavity walls were not acid treated after Er:YAG laser preparation. In group 2, only the enamel walls were acid treated. In group 3, all the enamel and dentin walls were acid treated. Microleakage was assessed using a methylene blue dye penetration method.

RESULTS

Bond strength values did not differ significantly between the three groups (P = 0.162). Better marginal adaptation was obtained between the composite resin and cavity walls when Er:YAG laser preparation was followed by a total acid etching (P = 0.008).

CONCLUSIONS

Our results supported the use of single-component adhesive systems in cavities prepared using Er:YAG laser. The step of acid etching must be maintained for the whole cavity walls in regard of the microleakage values.

Microleakage of class V resin composite restorations after conventional and Er:YAG laser preparation

This in vitro study compared the microleakage of Class V resin composite restorations at bevelled enamel/composite and dentin/composite interfaces following Er:YAG laser (pre-treatment modalities: laser-etching and/or acid-etching) or conventional preparation and acid-etch, in association with two resin composite formulations and their three-step adhesive system. Class V cavities with conventional bevel produced on the lingual and buccal surfaces of eighty extracted caries- and restoration-free human teeth, were assigned to eight groups: cavities were or Er:YAG-lased and acid-etched (groups 1 and 5); or Er:YAG-lased, laser-etched and acid-etched (groups 2 and 6); or Er:YAG-lased and only laser-etched (groups 3 and 7); or cut by dental drill at high-speed and acid-etched (groups 4 and 8). The specimens were restored with Optibond FL+Herculite XRV (groups 1, 2, 3 and 4) or with Scotchbond MP+Z 100 (groups 5, 6, 7 and 8), stored in distilled water at 37 degrees C for 24 h, thermocycled 1500 times between 5 and 55 degrees C, placed in a 2% aqueous solution of methylene blue for 24 h at 37 degrees C, embedded in resin and sectioned. Microleakage was assessed according to the depth of dye penetration along the restoration. There were statistically significant differences between occlusal and cervical regions for all groups (P<0.01) except for groups 3 and 7. Pair-wise comparison of groups showed that acid-etch is advocated when using resin composite in Er:YAG-lased Class V cavities; the seal at enamel margins in Er:YAG-lased and laser-etched cavities depended on the resin composite formulation and corresponding adhesive (P<0.05).