Effect of different surface treatments on the microtensile bond strength of two self-adhesive flowable composites.

The aim of this study was to evaluate the effect of different surface treatments on the microtensile bond strength (µTBS) of two different self-adhesive flowable composite materials (SACs) to dentin. Forty extracted human molars were horizontally flattened to expose the dentin surfaces. The teeth were divided into eight groups according to the surface treatments (acid etching, Er:YAG laser quantum square pulse (QSP) mode, and Er:YAG laser medium-short pulse (MSP) mode at 10 Hz, 1.2 W, 120 mJ, and control-SiC) and SAC type (Vertise Flow and Fusio Liquid Dentin) (n = 5). Light cured 4-mm-high composite build-ups were made on the dentin surfaces, and the specimens were sectioned into serial sticks (n = 15). Later, the specimens were attached to microtensile testing machine and tensile force was applied at a crosshead speed of 1 mm/min until failure occurred. The failure modes were evaluated using a stereomicroscope at ×40 magnification, and one sample from each group was used for scanning electron microscopy (SEM) evaluation. The data were analyzed with two-way ANOVA and Tukey's HSD test (α = 0.05). In all surface treatment groups along with the control groups, Vertise Flow showed better µTBS than the Fusio Liquid Dentin with the exception of the Er:YAG MSP mode surface treatment (p < 0.05). Etching with phosphoric acid and the Er:YAG QSP mode surface treatment significantly increased the µTBS of Vertise Flow (p < 0.05). Etching with phosphoric acid, Er:YAG QSP mode surface treatment, and Er:YAG MSP mode surface treatment significantly increased the µTBS of Fusio Liquid Dentin (p < 0.05). The µTBS of Vertise Flow was higher than the µTBS of Fusio Liquid Dentin. The Er:YAG laser irradiation increased the µTBS of both self-adhesive flowable resin composites in two pulse modes tested (MSP or QSP). However, the highest µTBS was recorded when Vertise Flow was applied with acid etching.

Antimicrobial effect of ozonated water, sodium hypochlorite and chlorhexidine gluconate in primary molar root canals.

OBJECTIVE: The aim was to determine the antimicrobial effect of ozonated water, ozonated water with ultrasonication, sodium hypochloride and chlorhexidine (CHX) in human primary root canals contaminated by Enterococcus faecalis (E. faecalis). MATERIALS AND METHODS: Fifty-eight extracted human primary molar teeth were used. Crowns were cut off using a diamond saw under water-cooling. One hundred roots were obtained and mechanically prepared. The roots were then sterilized by autoclaving in water for 15 min at 121°C. All samples were contaminated with E. faecalis for 24 h and the root canals were randomly divided into five groups (n = 20). Group I: 25 mg/L of Ozonated water (O3aq), Group II: 25 mg/L of O3aq with ultrasonication, Group III: 2.5% Sodium hypochloride (NaOCl), Group IV: 2% CHX and Group V: Positive control. The canal of each specimen was irrigated for 4 min and positive control was untreated. All root canals were agitated with sterile saline solution. The saline solution was collected from canals with sterile paper points. For each specimen, the paper points were transposed to eppendorf vials containing 2 ml of brain heart infusion. According to bacterial proliferation, the mean values of optical density were achieved by ELISA (Biotek EL ×800, Absorbance Microplate Reader, ABD) and the data were analyzed. RESULTS: NaOCI, CHX and two types of O3aq were found statistically different than positive control group. NaOCI irrigation was found significantly most effective. CONCLUSIONS: NaOCl, CHX and O3aq applications provide antibacterial effect in vitro conditions in primary root canals.