A novel carbamide peroxide polymeric nanoparticle bleaching gel: Color change and hydrogen peroxide penetration inside the pulp cavity.

OBJECTIVE: This study evaluated the hydrogen peroxide (HP) penetration inside the pulp cavity and the color change of teeth submitted to the 15% carbamide peroxide (CP) nanoparticle bleaching gel at several application times. MATERIALS AND METHODS: Premolars were divided into nine groups (n = 6) according to 15% CP bleaching agents (nanoparticle and commercial) and to application times (15, 30, 45, and 60 minutes). A negative control was exposed to ultra-purified water. After a whitening procedure, the HP concentration (µg/mL) inside the pulp cavity was assessed via spectrophotometry. The color change (ΔE* and ΔE00*) was evaluated with a spectrophotometer. Data were analyzed via two-way ANOVA and Tukey (α = 0.05). RESULTS: A lower concentration of HP was detected for CP nanoparticle gel after 30 and 45 minutes of whitening procedure (P = .001). The bleaching groups promoted a higher color change (ΔE* and ΔE00*) regardless of the application time (P = .0001). CONCLUSIONS: The CP nanoparticle gel reduced HP inside the pulp cavity, and showed effective bleaching compared with CP commercial gel. CLINICAL SIGNIFICANCE: Using 15% carbamide peroxide nanoparticle bleaching gel decreased the HP penetration inside the pulp cavity and may decrease bleaching-induced tooth sensitivity in at-home bleaching.

Dentin moisture does not influence postoperative sensitivity in posterior restorations: A double-blind randomized clinical trial.

PURPOSE: This double-blind, randomized clinical trial evaluated the influence of dentin moisture on postoperative sensitivity (POS) in posterior restorations using a simplified etch-and-rinse adhesive, until 12 months of clinical service. METHODS: 90 restorations were inserted in 45 patients to treat carious lesions or to replace existing posterior restorations with a depth ≥ 3 mm. After cavity preparation, the simplified etch-and-rinse adhesive (Adper Single Bond 2) was applied on dry or wet dentin followed by a bulk-fill resin composite (Filtek Bulk Fill) under rubber dam isolation. The patient's spontaneous and stimulated POS was evaluated at baseline and after 7 days, 6 months, and 12 months of clinical evaluation. The secondary parameters (marginal discoloration, marginal adaptation, fracture and recurrence of caries) were evaluated by World Dental Federation (FDI) criteria after 7 days, 6 and 12 months of clinical evaluation. RESULTS: No significant spontaneous and stimulated POS was observed when dry and wet dentin were compared (P> 0.05). A significant and higher risk of spontaneous POS (18.6%; 95% CI 9.7 to 32.6) occurred up to 48 hours after restoration placement for both groups when compared to all evaluation times (P< 0.03). However, the intensity of POS was mild at up to 48 hours with a difference between the dry and wet dentin groups (P> 0.79). When secondary parameters were evaluated, no significant difference between the groups were observed (P> 0.05). CLINICAL SIGNIFICANCE: The moisture level of the dentin substrate in posterior restorations does not influence POS in bulk-fill resin composite posterior restorations when associated with an etch-and-rinse ethanol-based adhesive system.

Açaí juice stains a glazed resin-modified glass-ionomer cement.

Coloured compounds (anthocyanins) in açaí can stain resin-modified glass-ionomer cement (RMGIC) due to its low staining resistance. AIM: The aim of this study was to assess whether açaí compromises the surface colour and roughness of RMGIC in vitro. MATERIALS AND METHOD: Disc-shaped specimens (2 mm thick, 8 mm in diameter) of Vitremer™ (3M ESPE, St Paul, MN, USA) were prepared according to the manufacturer 's instructions. The mixture was inserted into a silicone mouldplaced between two mylar strips, and light cured. Specimens were randomly divided into three groups (n=25) according to the solutions to be used for chemical degradation: artificial saliva (control), açaí sorbet and açaí juice. A spectrophotometer CM-2600d/2500d (Konica Minolta, Tokyo, Japan) was used to analyse the colour (CIELa*b* scale). Surface roughness (Ra, mm) was measuredusing theprofilometer Surfcorder SE 1700 (Kosaka Corp, Tokyo, Japan). The specimens were subjected to three daily soaks (6 ml, 15 minutes) for 14 days at 37°C. They were washed in distilled water and placed in fresh saliva (30 minutes in the interval). After the third soak in a day, they were stored in fresh saliva overnight. Outcomes were analysed at baseline (L*, a*, b*, Ra) and after degradation (L'*, a'*, b'*, Ra'). RESULTS: The pH values of saliva, sorbet, and juice were 7.0, 3.8, and 4.9, respectively. ΔE* values were 6.6 for saliva, 6.9 for sorbet and 7.8 for juice. There was a significant ΔE* difference between saliva (p=0.005) and juice (p=0.002), and between juice and sorbet (p=0.019), but none between saliva and sorbet (p=0.401). There was no significant Δb* difference between the solutions. No difference between juice and sorbet was observed for Δa*, but they were significantly different from saliva (p<0.001). Brightness (L*) changed significantly. Juice showed the highest ΔE* (7.8) and ΔL* (7.7). No significant change was observed for roughness and there was no difference between the solutions for ARa. CONCLUSIONS: Açaí and saliva led to unacceptable staining, but no significant roughness changes in the resin-modified glass-ionomer cement.

As antocianinas presentes no açaí podem manchar o cimento de ionomero de vidro modificado por resina (CIVMR) devido a baixa resistencia ao manchamento do material. OBJETIVO: O objetivo desse estudo foi avaliar se o açaí compromete a cor e a rugosidade de superficie de um CIVMR in vitro. MATERIAIS E MÉTODOS: Amostras (2 mm de espessura, 8 mm de diámetro) de Vitremer™ (3M ESPE, St Paul, MN, USA) foram preparadas de acordo com as instrugoes do fabricante. O materialfoi espatulado, inserido em um molde de silicone colocado entre duas tiras de poliestireno e fotopolimerizado. Após, as amostras foram randomizadas e alocadas em tres grupos (n=25) de acordo com as solugoes usadas para a degradagao química: saliva artificial (controle) e sorbet de açaí e suco de açaí. Utilizou-se o espectrofotometro CM-2600d/2500d (Konica Minolta, Tokyo, Japan) para a análise da cor (escala CIELa*b*) e o rugosímetro Surfcorder SE 1700 (Kosaka Corp, Tokyo, Japan) para a rugosidade de superficie (Ra, mm). As amostras foram submetidas a tres imersoes diárias (6 ml, 15 minutos) em cada solugao por 14 dias a 37°C, tendo sido lavadas em água destilada e mantidas em saliva fresca (30 minutos) nos intervalos. Após a terceira imersao no dia, as amostras foram mantidas em saliva renovada até o dia seguinte. As variáveis foram analisadas antes (L*, a*, b*, Ra) e depois da degradagao química (L'*, a'*, b'*, Ra'). RESULTADOS: Os valores de pH da saliva, sorbet e suco foram, respectivamente 7,0, 3,8 e 4,9. Houve diferenga significante para ΔE* entre saliva (p=0.005) e suco (p=0.002) e entre suco e sorbet (p=0.019), mas nao entre saliva e sorbet (p=0.401). Nao foi observada diferenga significante para Δb* entre as solugoes. Nao houve diferenga significante para Δa* entre suco e sorbet, mas eles foram significativamente diferentes da saliva (p<0.001). A luminosidade (L*) mostrou alteragao significante. O suco mostrou os maiores valores de ΔE* (7,8) e ΔL* (7,7)". Nao houve mudanga significante para a rugosidade e nao foi observada diferenga significante entre as solugoes para ARa (p>0.05). CONCLUSÃO: O açaí e a saliva causaram manchamento inaceitável do glaze do CIVMR e insignificante alteragao da rugosidade.