THE EFFECTS OF DIFFERENT DESENSITIZERS AND THEIR COMBINATIONS WITH ER, CR: YSGG LASER ON DENTIN TUBULES, AND SHEAR BOND STRENGTH TO DENTIN

AIM: The aim of this in vitro study was to investigate the effectiveness of Sodium Fluoride, Propolis and Er,Cr:YSGG laser alone and in combination with laser applications on dentin tubules by SEM and to examine the effects of these applications on the shear bond strength (SBS) of a universal adhesive to dentin. METHODS: Dentin samples obtained by removing the buccal enamel of 72 caries-free permanent, mandibular third molars were randomly divided into six groups (n:12): Control, Sodium Fluoride (Enamelast, Ultradent), Propolis (Fanus Propolis), Er,Cr:YSGG Laser (Biolase, Waterlase), Enamelast-Er,Cr:YSGG Laser, Propolis-Er,Cr:YSGG Laser. While the agents were applied to the dentin surfaces in the agents alone groups, laser was applied after the agent applications in the combination groups. No application was performed to the control group. After storing the samples in artificial saliva for 14 days, Clearfil Tri-S Bond Universal (Kuraray) and composite resin (Estelite Sigma Quick, Tokuyama) were applied to their surfaces. SBS tests were conducted using the Universal Tensile-Compression Test System (Instron 3382, USA). The tubule plugging efficiencies of the agents were examined on two dentin samples from each group by SEM. One-way analysis of variance (One-way ANOVA) was performed for statistical analysis of the data. For p<0.05, the results were considered statistically significant. RESULTS: No statistically significant difference was found in any comparison between all the test groups (p>0.05). In SEM examinations, occluded dentinal tubules were observed more frequently in the groups where the applications were performed in combination with laser, compared to the application of the agents alone. In the propolis group too, the tubules were usually closed, as well as open dentin tubules. CONCLUSIONS: Although combination applications of Er,Cr:YSGG Laser with Sodium Fluoride and Propolis showed greater dentin tubule plugging efficiency, these applications did not have a negative effect on the SBS of Clearfil Tri-S Bond Universal compared to the control group. The changes caused by the laser application on the dentin surface and the content of adhesive system may have prevented the SBS from being adversely affected

SHEAR BOND STRENGTH OF CHAIRSIDE CAD-CAM BLOCKS TO ERODED DENTIN

Objectives: To assess the shear bond strength (SBS) of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) blocks to dentin subjected to simulated gastric erosion when cemented with self-etch and self-adhesive resin cements. Materials and Methods: One hundred eighty dentin samples were assigned to two groups: sound and eroded dentin. In the eroded dentin group, samples were eroded with HCl (0.01 M, pH 2, 2 min) and stored in artificial saliva for 60 min then, brushed using a power brush (2N, 15 s). This cycle was repeated three times. CAD-CAM blocks (3x3x3 mm3, n=15/group) of Lava Ultimate (LU), Vita Enamic (VE), and Vita Suprinity (VS) were cemented to sound and eroded dentin with self-etch Multilink N (MN) and self-adhesive RelyX U200 Automix (RU) resin cements. SBS was measured after 24 hours. The failure mode was assessed by using a stereomicroscope. Data was analyzed with 3-way ANOVA and Bonferroni correction (p˂0.05). Results: The SBS was significantly affected by the main factors: tooth structure (p=0.011), resin cements (p˂0.001), and CAD-CAM blocks (p=0.001). When LU was cemented with RU to sound dentin, a higher SBS was obtained compared to eroded dentin (p=0.001). MN revealed significantly higher SBS than RU (

Evaluation of stabilized chlorine dioxide in terms of antimicrobial activity and dentin bond strength

Background: Antimicrobial agents are recommended for disinfection of the cavity following mechanical dental caries removal prior to application of restorative material. There is limited information about stabilized Chlorine Dioxide (ClO2) as a cavity disinfectant. Objectives: The objective of this study is to determine the antimicrobial activity and effect on dentin bond strength of ClO2 compared to chlorhexidine digluconate (CHX), sodium hypochlorite (NaOCl) and Ethanolic Propolis Extract (EPE). Methods: Antimicrobial activities of agents against oral pathogens (Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus casei, Candida albicans, and Saccharomyces cerevisiae) and analyses of EPE were examined. Seventyfive mandibular third molars were sectioned, prepared and divided into five subgroups (n=15/group). Cavity disinfectants (2% CHX, 2.5% NaOCl, 30% EPE, 0.3% ClO2) were applied to etched dentin prior to adhesive and composite build-up. Shear bond strength (SBS) was evaluated with a universal testing machine at a crosshead speed of 0.5 mm/min. The SBS data were analyzed with One-way Analysis of Variance (ANOVA) and Tukey's post-hoc test (p <0.05). The failure modes were evaluated with a stereomicroscope. Results: It was determined that the compared disinfectants were showed different inhibition zone values against oral pathogens. ClO2 exhibited the highest antimicrobial activity, followed by CHX, NaOCI and EPE, respectively. No statistically significant difference was observed in the SBS values between the disinfectant treated groups and control group. The failure modes were predominantly mixed. Conclusion: The use of 0.3% stabilized ClO2 as a cavity disinfectant agent exhibited high antimicrobial activity against oral pathogens and no adverse effects on SBS to etched dentin