PURPOSEThis article provides an overview of dental ceramics. It addresses possible modes of failure and factors that may influence the decision to either repair or replace ceramic restorations. The authors' intention was to present ceramic repair as a reliable, low-cost, low-risk technique.

The aim of this study was to evaluate the compressive strength of microhybrid (Filtek TM Z250) and nanofilled (Filtek TM Supreme XT) composite resins photo-activated with two different light guide tips, fiber optic and polymer, coupled with one LED. The power density was 653 mW cm 2 when using the fiber optic light tip and 596 mW cm 2 with the polymer. After storage in distilled water at 37 ± 2 C for seven days, the samples were subjected to mechanical testing of compressive strength in an EMIC universal mechanical testing machine with a load cell of 5 kN and speed of 0.5 mm min 1 . The statistical analysis was performed using ANOVA with a confidence interval of 95% and Tamhane's test. The results showed that the mean values of compressive strength were not influenced by the different light tips (p > 0.05). However, a statistical difference was observed (p < 0.001) between the microhybrid composite resin photo-activated with the fiber optic light tip and the nanofilled composite resin. Based on these results, it can be concluded that microhybrid composite resin photo-activated with the fiber optic light tip showed better results than nanofilled, regardless of the tip used, and the type of the light tip did not influence the compressive strength of either composite. Thus, the presented results suggest that both the fiber optic and polymer light guide tips provide adequate compressive strength to be used to make restorations. However, the fiber optic light tip associated with microhybrid composite resin may be an interesting option for restorations mainly in posterior teeth.

The aim was to evaluate the influence of different dentin preparation mode in the smear layer characteristics (SL), hybrid layer (HL), and microtensile bond strength (µTBS) to dentin with two resin cements. The occlusal dentin of 120 third molars was exposed. The teeth were divided into 4 groups (n=30) according to the dentin preparation mode: 1- fine grain diamond bur; 2- coarse grain diamond bur; 3- multi laminate carbide steel bur; and, 4- ultrasonic CV Dentus diamond bur. Each treated dentin group was divided into 2 sub-groups (n=15) according to the resin cement: (1) RelyX U200 and (2) RelyX ARC. Resin composite blocks were cemented on dentin. After storage at 37o C for 24 h, beams with a cross section area of 1.0 mm2 were obtained, and tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Two additional teeth for each sub-group were prepared to analyze the SL and HL on a scanning electron microscopy. According to Kruskal-Wallis test and Dunn tests, there was no significant difference in µTBS among the rotary instruments within each resin cement group. RelyX ARC obtained higher µTBS values compared to RelyX U200 (p<0.05). RelyX ARC formed evident HL, which was not observed for RelyX U200. The dentin mode preparation did not influence the µTBS of the resin cements. The SL was different for all instruments. The cementing agent is more determinant in the hybrid layer formation and bond strength to dentin than the instruments applied on dentin.

The laser has been widely used in many specialties of dentistry and several wavelengths have been investigated as a substitute for high-speed handpiece. The purpose of this paper is to review the literature about the use of Er:YAG and Er, Cr:YSGG lasers in cavity preparation for dental tissues. Despite the differences in wavelength, pulse duration and energy, the morphological characteristics of the irradiated dentin surface with these lasers are comparable, as well as its effects as methods of dental caries prevention. Thus, Er:YAG and Er, Cr:YSGG lasers prepared cavities with similar effects on the dental tissue, however, further investigations about ideal irradiation conditions are needed for both lasers. How to cite this article Santos CR, Tonetto MR, Presoto CD, Bandéca MC, Oliveira OB Jr, Calabrez-Filho S, Andrade MF. Application of Er:YAG and Er, Cr:YSGG Lasers in Cavity Preparation for Dental Tissues: A Literature Review. World J Dent 2012;3(4):340-343.

SUMMARYThe current study evaluated in-vitro microleakage of indirect composite inlays fixed with flowable composite and resinous cement and cured by LEDs and QTH units, thus modifying the internal conditioning of the inlays. Thirty-two non-carious teeth were selected and 64 cavity preparations were performed in both enamel and cementum. These teeth were divided into four groups: I-Elipar FreeLight appliance and Filtek Flowable composite; II-Ultralux appliance and Filtek Flowable composite; III-Elipar FreeLight appliance and RelyX cement and IVUltralux appliance and RelyX cement. The inlays were internally sandblasted with aluminum oxide, etched with 37% phosphoric acid, washed and silanized. The dental etching was carried out with 37% phosphoric acid for 15 seconds in Clinical RelevanceAn efficient polymerization of resin composite inlays associated with treatment of the surface and luting with dual resinous cement and flowable resin composites presents better longevity of restorations. 294Operative Dentistry dentin and 30 seconds in enamel. After being washed and dried, Single Bond dentinal adhesive was then applied, and the inlays were fixed with their respective luting agents, cured in close contact with their surfaces for 60 seconds, thermocycled and immersed in 0.5% basic fuchsine solution. The teeth were then washed and sectioned through the center of the restoration in order for the microleakage readings to be performed using the Image Tool Software. Then, ANOVA and Tukey's statistical tests were applied. In enamel, there was no significant difference for both groups with regard to microleakage; in cementum, the significant difference was 5% (p>0.005).In agreement with the results, the inlays can be fixed with RelyX and Filtek Flowable resins.