Influence of an arginine-containing toothpaste on bond strength of different adhesive systems to eroded dentin.

The aim of this study was to evaluate the bond strength of different adhesive systems to eroded dentin following toothbrushing with an arginine-containing toothpaste. Sixty standardized 3 × 3 × 2-mm fragments of root dentin (n = 10) were prepared. After all surfaces except the buccal surfaces were impermeabilized, specimens were subjected to an erosive wear protocol and stored for 24 hours at 37°C. The specimens underwent 1000 toothbrushing cycles with an arginine-containing toothpaste, an arginine-free toothpaste (positive control group), or artificial saliva (negative control group). Following application of a self-etching or an etch-and-rinse adhesive to the buccal surfaces of the specimens, 6-mm-high composite resin blocks were built up in 2-mm increments. After 24 hours' storage in 100% relative humidity, microtensile test specimens with an approximate area of 1 mm² were prepared. The test was performed at a speed of 0.5 mm/min until specimen fracture, and the failure patterns were evaluated using a stereoscopic loupe. Two-way analysis of variance revealed no significant difference between the toothpastes, the adhesive systems, or the interactions between toothpaste and adhesive system in terms of the bond strength to eroded dentin (P > 0.05). The predominant failure pattern was adhesive in all groups. It was concluded that a toothpaste containing arginine did not interfere with the bond between either the self-etching or the etch-and-rinse adhesive system and eroded dentin.

Evaluation of bond strength of silorane and methacrylate based restorative systems to dentin using different cavity models.

OBJECTIVE: The aim of this in vitro study was to evaluate the microtensile bond strength (µTBS) to dentin of two different restorative systems: silorane-based (P90), and methacrylate-based (P60), using two cavity models. MATERIAL AND METHODS: Occlusal enamel of 40 human third molars was removed to expose flat dentin surface. Class I cavities with 4 mm mesial-distal width, 3 mm buccal-lingual width and 3 mm depth (C-factor=4.5) were prepared in 20 teeth, which were divided into two groups (n=10) restored with P60 and P90, bulk-filled after dentin treatment according to manufacturer's instructions. Flat buccal dentin surfaces were prepared in the 20 remaining teeth (C-factor=0.2) and restored with resin blocks measuring 4x3x3 mm using the two restorative systems (n=10). The teeth were sectioned into samples with area between 0.85 and 1.25 mm2 that were submitted to µTBS testing, using a universal testing machine (EMIC) at speed of 0.5 mm/min. Fractured specimens were analyzed under stereomicroscope and categorized according to fracture pattern. Data were analyzed using ANOVA and Tukey Kramer tests. RESULTS: For flat surfaces, P60 obtained higher bond strength values compared with P90. However, for Class I cavities, P60 showed significant reduction in bond strength (p<0.05). No statistical difference between restorative systems was shown for Class I cavity model (p>0.05), or between Class I Cavity and Flat Surface group, considering P90 restorative system (p>0.05). Regarding fracture pattern, there was no statistical difference among groups (p=0.0713) and 56.3% of the fractures were adhesive. CONCLUSION: It was concluded that methacrylate-based composite µTBS was influenced by cavity models, and the use of silorane-based composite led to similar bond strength values compared to the methacrylate-based composite in cavities with high C-factor.

Evaluation of bond strength of silorane and methacrylate based restorative systems to dentin using different cavity models

OBJECTIVE: The aim of this in vitro study was to evaluate the microtensile bond strength (µTBS) to dentin of two different restorative systems: silorane-based (P90), and methacrylate-based (P60), using two cavity models. MATERIAL AND METHODS: Occlusal enamel of 40 human third molars was removed to expose flat dentin surface. Class I cavities with 4 mm mesial-distal width, 3 mm buccal-lingual width and 3 mm depth (C-factor=4.5) were prepared in 20 teeth, which were divided into two groups (n=10) restored with P60 and P90, bulk-filled after dentin treatment according to manufacturer's instructions. Flat buccal dentin surfaces were prepared in the 20 remaining teeth (C-factor=0.2) and restored with resin blocks measuring 4x3x3 mm using the two restorative systems (n=10). The teeth were sectioned into samples with area between 0.85 and 1.25 mm2 that were submitted to µTBS testing, using a universal testing machine (EMIC) at speed of 0.5 mm/min. Fractured specimens were analyzed under stereomicroscope and categorized according to fracture pattern. Data were analyzed using ANOVA and Tukey Kramer tests. RESULTS: For flat surfaces, P60 obtained higher bond strength values compared with P90. However, for Class I cavities, P60 showed significant reduction in bond strength (p<0.05). No statistical difference between restorative systems was shown for Class I cavity model (p>0.05), or between Class I Cavity and Flat Surface group, considering P90 restorative system (p>0.05). Regarding fracture pattern, there was no statistical difference among groups (p=0.0713) and 56.3% of the fractures were adhesive. CONCLUSION: It was concluded that methacrylate-based composite µTBS was influenced by cavity models, and the use of silorane-based composite led to similar bond strength values compared to the methacrylate-based composite in cavities with high C-factor. .