Evaluation of Proanthocyanidin-based dentifrices on dentin-wear after erosion and dental abrasion - In situ study.

Background: Proanthocyanidin has been considered as a preventive agent against erosion because of its properties, which involves remineralization, reduction of demineralization and matrix metalloproteinases (MMPs) inhibition. Thus, the aim of this in situ study was to evaluate the effect of proanthocyanidin-based dentifrices on wear resistance of dentin specimens subjected to erosion associated with abrasion. Material and Methods: This crossover double-blinded study was performed in 5 phases of 5 days each, with 10 healthy volunteers who wore 5 palatal devices (1 for each phase) with 4 dentin specimens. The groups under study were: G1 - placebo dentifrice (negative control group); G2 - 0.012% chlorhexidine dentifrice (1st positive control group); G3 - NaF 1110 ppm fluoride dentifrice (2nd positive control group); G4 - 10% purified proanthocyanidin dentifrice (1st test group); G5 - fluoride + proanthocyanidin dentifrice (2nd test group). Erosion was performed by palatal device immersion in acid beverage (Coca-cola®), 3 times daily for 5 minutes during 5 days. Abrasion was applied after the first and third erosive cycles by using a eletric toothbrush during 15 seconds in each specimen with the application of the studied dentifrices slurry. The response variable was depth of dentin loss (µm) measured by profilometry. Data were analyzed by Repeated Measures Analysis of Variance followed by LSD Fisher's test (p<0.05). Results: Data (G1: 1.76 ± 0.55A; G2: 1.19 ± 0.42B; G3: 1.29 ± 0.34B; G4: 0.93 ± 0.38C; G5: 0.82 ± 0.34C) showed that G4 and G5 did not presented significant difference between them, but showed less dentine loss when compared to all other groups. G1 presented the highest dentin wear. Conclusions: Proanthocyanidin and the combination of proanthocyanidin and fluoride dentifrices revealed the best results, showing that these formulations could be a promising alternative for patients who suffer with dentin erosion. Key words:Dentin, erosion, cross-liking agent, metalloproteinases, toothpastes.

Dentin bond strength evaluation between a conventional and universal adhesive using etch-and-rinse strategy

Aim: The aim of this study was to compare the microtensile bond strength (µTBS) and the characteristics of the adhesive interface of Scotchbond Universal - SU ­ etch-and-rise mode (3M ESPE) and Adper Scotchbond Multi-Purpose - MP (3M ESPE) to dentin over time. Methods: Class I cavity preparations were performed in 60 human molars that were randomly divided according to the dentin bonding system (DBS) used (n=30): (1) Acid conditioning + SU and (2) Acid conditioning + MP. For bonding strength (BS) analysis, 30 teeth (n = 15) were sectioned into sticks and submitted to the microtensile test in a universal testing machine after 24 hours and 12 months. The adhesive interface of the others 30 teeth was analyzed in a confocal microscope after 24 hours and 12 months. The data of µTBS were analyzed by two-way repeated measures ANOVA and Tukey's HSD (α = 0.05). Results: SU presented the lowest DBS compared to MP (p=0.000). Time did not influenced DBS for both adhesive systems (p=0.177). Confocal microscopy analysis showed no cracks between both adhesive systems tested. Conclusion: The results indicate that MP - µTBS showed a better performance compared to SU in total-etch mode

Micro-sized erosions in a nanofilled composite after repeated acidic beverage exposures: consequences of clusters dislodgments.

OBJECTIVE: To evaluate the hardness (KHN), color stability (DE), and superficial micromorphology of two categories of composites after immersion in either distilled water or grape juice for up to 45 days. MATERIAL AND METHODS: Cylindrical specimens (6 mm diameter x 2 mm thick) were obtained according to the factors: composite [Opallis (FGM) and Filtek Z350XT (3M ESPE)]; immersion solution (distilled water and grape juice); and evaluation time: 24 h and 7, 14, 21, 28, and 45 days. After photoactivation, the specimens were stored at 37 ºC for 24 h. KHN (50 g/15 s) and ΔE were then repeatedly assessed according to the immersion solutions. Data were analyzed (three-way ANOVA/Tukey's test). Scanning electron microscopy (SEM) topographic analysis was also performed. RESULTS: In general, KHN of both composites reduced after 24 h, irrespective of the immersion solution and time. A significantly lower KHN was noted for Opallis compared with Filtek Z350XT in all parameters. An increase in ΔE over time was noted for both composites, irrespective of the immersion solution. Significantly higher ΔE was noted for Filtek Z350XT immersed in grape juice compared with Opallis, regardless of the evaluation time. The grape juice caused significantly higher DE compared with water in all periods. SEM analysis showed eroded areas for Filtek Z350XT but not for Opallis. CONCLUSIONS: The compositions and immersion solutions influence the composite hardness and the color stability. In spite of the higher hardness, the nanofilled composite is more susceptible to color change than the microhybrid when immersed in an acidic dyed solution.

Micro-sized erosions in a nanofilled composite after repeated acidic beverage exposures: consequences of clusters dislodgments

Objective: To evaluate the hardness (KHN), color stability (DE), and superficial micromorphology of two categories of composites after immersion in either distilled water or grape juice for up to 45 days. MATERIAL AND METHODS: Cylindrical specimens (6 mm diameter x 2 mm thick) were obtained according to the factors: composite [Opallis (FGM) and Filtek Z350XT (3M ESPE)]; immersion solution (distilled water and grape juice); and evaluation time: 24 h and 7, 14, 21, 28, and 45 days. After photoactivation, the specimens were stored at 37ºC for 24 h. KHN (50 g/15 s) and ΔE were then repeatedly assessed according to the immersion solutions. Data were analyzed (three-way ANOVA/Tukey's test). Scanning electron microscopy (SEM) topographic analysis was also performed. RESULTS: In general, KHN of both composites reduced after 24 h, irrespective of the immersion solution and time. A significantly lower KHN was noted for Opallis compared with Filtek Z350XT in all parameters. An increase in ΔE over time was noted for both composites, irrespective of the immersion solution. Significantly higher ΔE was noted for Filtek Z350XT immersed in grape juice compared with Opallis, regardless of the evaluation time. The grape juice caused significantly higher DE compared with water in all periods. SEM analysis showed eroded areas for Filtek Z350XT but not for Opallis. CONCLUSIONS: The compositions and immersion solutions influence the composite hardness and the color stability. In spite of the higher hardness, the nanofilled composite is more susceptible to color change than the microhybrid when immersed in an acidic dyed solution. .