Effect of Sodium Ascorbate and Ascorbic Acid Hydrogels on Microleakage of Composite Restorations after an Office Bleaching Protocol

Abstract

Aim: This study evaluated the infl uence of 20% sodium ascorbate (SA) and 10% ascorbic acid (AA) hydrogels on the microleakage of class V composite restorations after an offi ce bleaching protocol (B). Methods: Sixty bovine incisors were sectioned at one point extending 8 mm from the amelodentinal junction toward the incisal edge, and at a second point extending 2 mm from the amelodentinal junction toward the root apex. Root canals were sealed with a composite and the teeth were divided into 5 groups. In Group C (control group), the teeth were prepared (P; 4 × 3 mm depth × diameter; diamond bur 3131, KG Sorensen), etched, rinsed (ER), submitted to an adhesive system protocol (Ambar, FGM), and restored (R) with a microhybrid composite (Opallis, FGM); In Group IR, the teeth were bleached (B; 2 sessions, 1 week interval, 35% hydrogen peroxide, Whitness HP Blue, FGM) + P + ER + R; In Group SA, teeth were B + P + SA (20%/15 minutes) + ER + R; In Group AA, teeth were B + P + AA (10%/15 minutes) + ER + R; and in Group MR, the teeth were B + stored in water (37°C/14 days) + P + ER + R. Specimens were submitted to an aging process by thermocycling (5 × 10 4 cycles of 5°C and 55°C with a dwelling time of 30 s), varnish-sealed, immersed in basic fuchsin (3 h), washed and sectioned with a diamond disc. Microleakage was measured with the aid of ImageTool  software. ANOVA and Tukey's post hoc test (p < 0.05) were applied. Results: Microleakage (mm) and standard deviations per group were as follows: C, 0.29 (0.06) A ; IR, 1.86 (0.15) C ; SA, 1.08 (0.09) B ; AA, 1.07 (0.10) B ; MR, 1.02 (0.12) B . Conclusions: Bleached teeth submitted to superfi cial treatment with 20% SA and 10% AA applied for 15 minutes prior to restoration presented reduced microleakage, as compared to immediately restored bleached teeth. Use of these antioxidants led to a microleakage comparable to that observed after a waiting period of 14 days prior to restoration. Dental Materials; Dental Leakage; Tooth Bleaching.Efeito de hidrogéis de ascorbato de sódio e ácido ascórbico na microinfi ltração de restaurações de resina composta realizadas após aplicação de um protocolo de clareamento em consultório • Objetivo: Este estudo avaliou a infl uência da utilização de hidrogéis de ascorbato de sódio (SA) e ácido ascórbico (AA) na microinfi ltração de restaurações classe V de resina composta realizadas após a aplicação de um protocolo de clareamento em consultório (B). Métodos: Sessenta incisivos bovinos foram seccionados a 8 mm da junção amelodentinária em direção incisal e a 2 mm em direção ao ápice radicular. Os canais radiculares foram selados com um compósito e os dentes foram divididos em 5 grupos: no grupo C (controle), os dentes foram preparados (P; 4 × 3 mm profundidade × diâmetro; ponta diamantada 3131, KG Sorensen), condicionados, lavados (ER), submetidos a um protocolo adesivo (Ambar, FGM) e restaurados (R) com uma resina composta microhíbrida (Opallis, FGM); no grupo IR, os dentes foram clareados (B; 2 sessões, 1 semana de intervalo, peróxido de hidr...

Bonding to bleached enamel treated with 10% sodium bicarbonate: a one-year follow-up

“…In order to meet the high aesthetic demands of the patients nowadays, replacing these restorations immediately after teeth bleaching is eventually mandatory, as described in this case report. With regards to these situations where the dentist cannot wait the seven days intended for the optimal replacement of the restorations [8,9], many alternatives have been described in the literature [10][11][12] and the use of antioxidants is a handy one [9,11,13,15,16].…”

“…In this context, the use of antioxidants can be highlighted since it seems to be a more effective alternative to reduce or remove the residual oxygen [11,14]. The sodium ascorbate is the most investigated antioxidant [9,[13][14][15] and despite its efficiency in reducing microleakage has been pointed out previously [15], there is still some controversy about its mechanisms [11]. Recent study [16] have shown promising results with the application of the 10% sodium bicarbonate (SB), present in whitening kits, for 5 min on bleached enamel.…”

Treatment after bleaching for optimal bonding

“…5 To handle compromised bond strength of pre-bleached dental hard tissue, use antioxidant like sodium ascorbate. 2 , 5 , 7 , 8 , 9 , 14 , 15 As a practical approach, place 10% sodium ascorbate on the bleached surface for 10 minutes with agitation and rinse it with water before bonding. 2 …”