Effect of natural agents on the bond strength to eroded dentin.

OBJECTIVE: This study evaluated the effect of bromelain and propolis extract on the bond strength (BS) of a universal adhesive system to eroded dentin. MATERIALS AND METHODS: Sixty human molars with exposed dentin were halved, with one half protected by composite resin and the other subjected to erosive treatment followed by remineralization. After the erosive treatment, the composite resin was removed, and the teeth were randomly assigned to three groups (n = 20): Adhesive-Control System; Br-10%; Pr-16%. Following the treatments, composite resin blocks were built on the dentin surfaces and sticks of 0.9 mm2 were obtained and stored in distilled water at 37°C for 24 h and 6 months. After these periods, the sticks underwent bond strength testing and the data were analyzed using 2-way ANOVA, Bonferroni test, p < 0.05. Fracture patterns were observed using light microscope and scanning electron microscopy. RESULTS: Irrespective of the substrate and aging duration, propolis demonstrated higher BS (p < 0.05) compared to the other treatments. Eroded dentin exhibited greater removal of the smear layer and dentinal tubules with a larger diameter than sound dentin, especially when treated with bromelain, resulting in the formation of resin tags. CONCLUSIONS: Propolis consistently promoted the highest bond strength, irrespective of aging or substrate. Eroded dentin treated with propolis, or bromelain exhibited a higher prevalence of non-adhesive fractures and resin tag formation. CLINICAL SIGNIFICANCE: Propolis shows promise for enhancing the longevity of adhesive restorations in eroded dentin due to its ability to promote high bond strength.

Color stability and surface roughness of composite resins submitted to brushing with bleaching toothpastes: An in situ study.

OBJECTIVE: To evaluate, in situ, the color stability (CS) and surface roughness (SR) of composite resins after toothbrushing with whitening toothpaste. MATERIALS AND METHODS: Specimens (6 × 2 mm/) of composite resin (Tetric N-Ceram, Z250 and Z350) were randomly fixed on thirty participants' upper molars (buccal surface). For an initial standardization (7 days), participants used a soft toothbrush and nonwhitening toothpaste (SDB - Sorrisos Dentes Brancos). Initial CS (Easyshade) and SR (Surfcorder RS) measurements were performed. For SR, impressions of specimens were taken (Express, 3 M ESPE) to produce replicas in polyurethane resin (Axon F16, Abcol). Participants were randomly separated into three groups (n = 10) regarding used toothpaste (SDB; Close up White Now - CWN; Colgate Luminous White - CLW). After 90 days, CS and SR measurements were obtained, and data were analyzed (2-way ANOVA, repeated measures, Bonferroni, P < .05). RESULTS: Z250 showed higher (P < .05) color change than Z350. Tetric N-Ceram presented an intermediary value for ΔE, however, it also demonstrated higher SR (P < .05) after brushing with CLW, compared with SDB and CWN. CONCLUSIONS: The SR change of composite resin after toothbrushing with a whitening toothpaste is material dependent, but the toothpaste abrasiveness does not change the CS. CLINICAL SIGNIFICANCE: Whitening toothpaste do not change the color stability of composites; however, it can alter the restorative composite surface roughness.