Effect of Different Cavity Disinfectants on Microleakage

BACKGROUND Cavity disinfectants are frequently used for the elimination of bacteria that remain in the cavity, which are shown as the cause of secondary caries. However, its effect on microleakage from the tooth-restoration interface is still under investigation. The purpose of this study was to compare and evaluate the effects of the use of three different cavity disinfectants on microleakage in Class V composite restorations. METHODS For this study, 28 permanent third molar teeth without caries and restoration were used. Class V cavities of 4 mm x 3 mm x 3 mm were prepared on the buccal surfaces of each tooth. The teeth were randomly divided into 4 groups, with 7 teeth in each group. No cavity disinfectant was applied to the teeth in group 1. Tubulicid Red Label (Dental Therapeutics AB, Sweden) cavity disinfectant was applied to the 2nd group teeth, Cavity Cleanser (BISCO Inc., USA) cavity disinfectant to the 3rd group teeth, and Oxygenated Water (Dermosept, Turkey) cavity disinfectant to the 4th group teeth. Composite resin with universal adhesive and nanohybrid filler was applied to all samples in the groups in accordance with the recommendations of the manufacturers, and finishing and polishing processes were performed. Then, the thermal cycle (NOVA, Konya, Turkey) procedure was applied. After the restorations were covered with nail polish, they were kept in a 5 % basic fuchsin solution. The teeth were cut vertically in the buccolingual direction and examined with a stereomicroscope at x 40 magnification. The results were statistically evaluated with Kruskal-Wallis and Mann-Whitney U tests. RESULTS When the microleakage scores were compared between the control group and the groups treated with Tubulicid Red Label (p:0.204), Cavity Cleanser (p:0.204) and Oxygenated Water (P: 0.788), it was determined that there was no statistically significant difference (P > 0.05). CONCLUSİONS It was determined that different cavity disinfectants applied in Class V cavities did not have a negative effect on microleakage and the closest results to the control group were seen in the group where cavity cleanser disinfectant containing 2 % chlorhexidine digluconate was applied. KEY WORDS Cavity Disinfectants, Class V Cavity, Microleakage.

Evaluation of Dentin Microroughness and Composite Bond Strength After Multiple Uses of Diamond Burs

Using a bur multiple times to prepare dental structure may produce a smoother final surface on dentin than a new one. This superficial roughness may affect adhesion with resin-based materials by modifying the substrates’ characteristics. The aim of this study was to evaluate the effect of multiple uses of diamond burs on dentin’s superficial microroughness and bond strength with resin composite when using a self-etch adhesive. Diamond dental burs were used to simulate a preparation (dentin flat surface) on extracted third molars. Samples were distributed into groups according to burs’ number of previous uses as follows: 0, 1, 5 and 10. Scanning electron microscopy images at 70x, 350x, and 1000x were used to illustrate burs’ deformation. Each specimen’s dentin microroughness was measured three times to compare between experimental groups and the micro-shear bond strength test (n=15) was performed for the 0 and 10 uses groups using a universal adhesive in a self-etching mode. Diamond crystals wear and dislodgements were evident among groups where the burs were used more times. As the number of uses increased the mean microroughness of the dentin surface decreased with significant differences between the 0 and 10 uses groups. No statistical differences between experimental groups resulted from bond strength tests. When using a universal adhesive in a self-etching mode, the number of previous uses of a diamond bur seems to have no significant effect on dentin/resin composite bond strength.

Impact of Immediate Dentin Sealing Using Universal Adhesive under Simulated Pulp Pressure on Microtensile Bond Strength of Indirect Resin Composite Restorations and Dentin Permeability

Objective The aim of this study was to investigate the effect of immediate dentin sealing (IDS) technique using universal adhesive under simulated pulp pressure on microtensile bond strength (µTBS) of indirect resin composite restorations and dentin permeability. Materials and Methods Fifty extracted caries-free human third molars were used for specimens' preparation. Each molar's occlusal table was abraded flat and their roots were separated under continuous water cooling. Forty specimens were used for microtensile bond strength test (µTBST) evaluation. The µTBST specimens were randomly assigned to two groups according to the dentin sealing time; Immediate dentin sealing (IDS) and delayed dentin sealing (DDS). Each group was further subdivided into two subgroups according to the adhesive system used for dentin sealing: iBOND self-etch adhesive and GLUMA Bond Universal. All specimens were exposed to simulated pulp pressure for 1 week then restored using computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite blocks. The µTBS was evaluated for all tested subgroups after 24 hours and 6 months of water storage. The remaining 10 teeth were used for the preparation of dentin discs for dentin permeability evaluation. They were divided into two groups according to type of self-etch adhesive used. Fluid filtration rate was evaluated after etching, with smear layer and after adhesive application. Results obtained were statistically analyzed using Shapiro–Wilk test and Weibull analysis. Results Statistically significant difference was recorded between μTBS mean values of both IDS and DDS techniques at 24 hours and after 6 months of water storage. GLUMA Bond Universal adhesive had significantly higher bond strength compared with iBond at both IDS and DDS techniques, but both adhesives showed a significant reduction in the Weibull characteristic strength after 6 months of water storage. Significant reduction in dentin permeability was recorded by both adhesives without any significant difference between them. Conclusions The IDS technique using universal adhesive in self-etch mode is an effective strategy for improving the final bond strength of CAD/CAM resin composite restorations and reducing dentin permeability.

Sodium p-Toluenesulfinate Enhances the Bonding Durability of Universal Adhesives on Deproteinized Eroded Dentin

The effects of deproteinization using sodium hypochlorite (NaOCl) and the subsequent application of an antioxidant (sodium p-toluenesulfinate, STS) onto the bonding durability of universal adhesives on eroded dentin were investigated. Untreated sound dentin served as the control, whereas eroded dentin, which had been prepared by pH-cycling in 1% citric acid and a remineralization solution, was either untreated, deproteinized with a 10% NaOCl gel or deproteinized with the 10% NaOCl gel and subsequently treated with an STS-containing agent. The dentin surfaces were bonded using a universal adhesive (Clearfil Universal Bond Quick, Scotchbond Universal or G-Premio Bond), and the micro-tensile bond strength (µTBS) test was performed after 24 h or 10,000 thermal cycles. The µTBS data were statistically analyzed using a three-way ANOVA and Tukey’s HSD post hoc tests. The lowest µTBS was measured on untreated eroded dentin (p < 0.001). Deproteinization of eroded dentin resulted in µTBS similar to untreated sound dentin (p > 0.05), but the highest µTBS was obtained if deproteinization was followed by the application of STS. Thermocycling significantly decreased µTBS in all groups (p < 0.001), except for STS-treated, deproteinized, eroded dentin (p > 0.05). This indicated that deproteinization, followed by the application of STS, could enhance the bonding durability of universal adhesives on eroded dentin.