de Almeida Leticia Cunha Amaral Gonzaga, Soares Diana Gabriela, Azevedo Fernanda Almeida, Gallinari Marjorie de Oliveira, Costa Carlos Alberto de Souza, dos Santos Paulo Henrique, Briso André Luiz Fraga
Department of Restorative Dentistry, Araçatuba School of Dentistry, Univ Estadual Paulista, Araçatuba, SP, BR.
Department of Physiology and Pathology, Araraquara School of Dentistry, Univ Estadual Paulista, Araraquara, SP, BR.
Braz Dent J. 2015 Jul-Aug;26(4):378-83. doi: 10.1590/0103-6440201300380.
This study evaluated the color change, cytotoxicity and hydrogen peroxide (HP) diffusion caused by different home bleaching protocols: 10% carbamide peroxide (CP) for 3 or 1.5 h, 6% hydrogen peroxide for 1.5 h or 45 min. To quantify the peroxide penetration, disks of bovine teeth were placed in artificial pulp chambers (APCs) containing acetate buffer, which was collected for evaluation in a spectrophotometer. For analysis of cytotoxicity, specimens were adapted in APCs containing culture medium, which subsequently was applied on MDPC-23 odontoblast-like cells for 1 h. Cellular metabolism was evaluated by methyl tetrazolium (MTT) assay and the color change of the specimens was analyzed using the CIE L * a * b * system. The data were submitted to ANOVA and Fisher test (α=5%). The treatment with 10% CP for 3 h was the most effective, and 6% HP for 45 min produced the lowest color change. The groups 10% CP for 1.5 h and 6% HP for 45 min had the lowest trans-enamel dentinal HP penetration, and the 6% HP for 1.5 h had the highest. None of the protocols affected cellular metabolism and morphology. In conclusion, reduced peroxide exposure time reduced the bleaching result; higher HP diffusion did not mean higher effectiveness.
本研究评估了不同家庭漂白方案引起的颜色变化、细胞毒性和过氧化氢（HP）扩散情况：10%过氧化脲（CP）作用3小时或1.5小时、6%过氧化氢作用1.5小时或45分钟。为了量化过氧化物的渗透情况，将牛牙切片置于含有醋酸盐缓冲液的人工牙髓腔（APC）中，收集缓冲液并在分光光度计中进行评估。为了分析细胞毒性，将样本适配于含有培养基的APC中，随后将培养基应用于MDPC - 23成牙本质细胞样细胞1小时。通过甲基噻唑基四唑（MTT）法评估细胞代谢，并使用CIE L * a * b *系统分析样本的颜色变化。数据采用方差分析和Fisher检验（α = 5%）。10% CP处理3小时是最有效的，6% HP处理45分钟产生的颜色变化最小。10% CP处理1.5小时组和6% HP处理45分钟组的釉质牙本质HP渗透最低，6% HP处理1.5小时组的渗透最高。所有方案均未影响细胞代谢和形态。总之，过氧化物暴露时间缩短会降低漂白效果；较高的HP扩散并不意味着更高的有效性。
