Cavalli V, Silva B G, Berger S B, Abuna G, Marson F C, Tabchoury Cpm, Giannini M
Oper Dent. 2017 Mar/Apr;42(2):E44-E54. doi: 10.2341/16-079-L. Epub 2016 Nov 28.
This study aimed to quantify the concentration of hydrogen peroxide into the pulp chamber in the presence or absence of adhesive enamel restorations and to analyze the resin-dentin interface of bleached groups. Bovine incisors (120) were randomly divided into three groups according to enamel treatment (n=40 each): (1) enamel without restoration (control); (2) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a silorane-based (SB) system; or (3) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a dimethacrylate-based (DB) system. Restorations were thermocycled, and all groups were submitted to one application of 35% hydrogen peroxide (HP) agent for 45 minutes and subjected to four light activation methods (n=10 each): without light, light-emitting diode (LED), LED/diode laser, or halogen light. Acetate buffer solution was placed into the pulp chamber before bleaching, and this solution was collected to spectrophotometrically determine the concentration of HP that reached the pulp chamber after bleaching. Rhodamine B was added to the HP agent and applied on additional enamel samples of each group for 24 hours. Samples were sectioned mesiodistally, and the bleaching agent was traced using confocal microscopy. According to two-way analysis of variance and Tukey test (α=0.05), the HP concentration in the pulp chamber of the control group was significantly lower than that of the SB group (p<0.05), regardless of light activation. No differences were observed between DB and SB groups and between control and DB groups, except for the DB halogen light activated group, which exhibited higher HP intrapulpal concentration (p<0.05). Confocal microscopy exhibited HP diffusion through the interface of the SB and DB restored groups as well as enamel prisms in the control group. The SB restorative system increased the HP diffusion into the pulp chamber, but HP was able to diffuse even in the absence of enamel restorations.
本研究旨在量化在有无粘结性牙釉质修复体的情况下，过氧化氢进入牙髓腔的浓度，并分析漂白组的树脂-牙本质界面。将120颗牛切牙根据牙釉质处理方式随机分为三组（每组n = 40）：（1）未修复的牙釉质（对照组）；（2）用基于硅氧烷的（SB）系统修复的牙釉质龋洞（直径3 mm×深度1.5 mm）；或（3）用基于二甲基丙烯酸酯的（DB）系统修复的牙釉质龋洞（直径3 mm×深度1.5 mm）。修复体进行热循环处理，所有组均接受一次35%过氧化氢（HP）试剂处理45分钟，并采用四种光活化方法（每组n = 10）：无光、发光二极管（LED）、LED/二极管激光或卤素光。在漂白前将醋酸缓冲溶液置于牙髓腔中，并收集该溶液以分光光度法测定漂白后到达牙髓腔的HP浓度。将罗丹明B添加到HP试剂中，并应用于每组额外的牙釉质样本上24小时。样本沿近远中方向切片，并用共聚焦显微镜追踪漂白剂。根据双向方差分析和Tukey检验（α = 0.05），无论光活化情况如何，对照组牙髓腔中的HP浓度均显著低于SB组（p < 0.05）。除DB卤素光活化组牙髓腔内HP浓度较高（p < 0.05）外，DB组和SB组之间以及对照组和DB组之间未观察到差异。共聚焦显微镜显示HP在SB和DB修复组的界面以及对照组的牙釉质棱柱中扩散。SB修复系统增加了HP向牙髓腔的扩散，但即使在没有牙釉质修复体的情况下HP也能够扩散。
