Sa Patricia Marra de, Jeronymo Raffaela Di Iorio, Yui Karen Cristina Kazue, Silva Eduardo Galera da, Huhtala Maria Filomena Rocha Lima, Torres Carlos Rocha Gomes, Gomes Ana Paula Martins
Department of Restorative Dentistry, São Josédos Campos School of Dentistry, UNESP São Paulo State University São Paulo, Brazil.
J Contemp Dent Pract. 2011 May 1;12(3):158-63. doi: 10.5005/jp-journals-10024-1027.
This in vitro study evaluated the effect of calcium hydroxide on pH changes of the external medium after intracoronal bleaching.
A total of 50 extracted human premolars were prepared and filled with gutta-percha and endodontic sealer. The teeth were randomly divided into five groups according to the bleaching agents employed: (a) Sterile cotton pellet with distilled water (control group); (b) sodium perborate and distilled water; (c) sodium perborate and 10% carbamide peroxide; (d) sodium perborate and 35% hydrogen peroxide; (e) 35% hydrogen peroxide. The teeth were stored in vials containing distilled water and the pH values of the medium surrounding the teeth were analyzed. After 7-day storage, the bleaching agent was removed and replaced by calcium hydroxide, and the distilled water was changed, in which the teeth were kept stored for further 14 days. Measurement of pH of the external medium (distilled water) was performed 7 days after insertion of the bleaching agents, immediately, 7 and 14 days after insertion of the calcium hydroxide. Data were submitted to statistical analysis by the two-way ANOVA and Tukey,s test.
There were pH changes of the external medium at 7- day period after bleaching procedures. These results confirmed the diffusion of bleaching agents to the external medium.
Calcium hydroxide increased the external medium pH and was effective for pH alkalinization after intracoronal bleaching.
Intracoronal bleaching of endodontically treated teeth may cause cervical root resorption. A possible explanation for this process is the passage of bleaching agents to the periodontal tissues yielding an inflammatory process. In an attempt to keep the neutrality of the periodontal pH, the calcium hydroxide has been recommended.Results of this study showed that this material should be always used after intracoronal bleaching.
本体外研究评估了氢氧化钙对冠内漂白后外部介质pH变化的影响。
共制备50颗拔除的人前磨牙，用牙胶和根管封闭剂充填。根据所使用的漂白剂将牙齿随机分为五组：（a）用蒸馏水的无菌棉球（对照组）；（b）过硼酸钠和蒸馏水；（c）过硼酸钠和10%过氧化脲；（d）过硼酸钠和35%过氧化氢；（e）35%过氧化氢。将牙齿储存在装有蒸馏水的小瓶中，分析牙齿周围介质的pH值。储存7天后，去除漂白剂，用氢氧化钙替代，更换蒸馏水，将牙齿继续保存14天。在插入漂白剂7天后、立即、插入氢氧化钙7天和14天后测量外部介质（蒸馏水）的pH值。数据通过双向方差分析和Tukey检验进行统计分析。
漂白程序后7天，外部介质的pH值发生了变化。这些结果证实了漂白剂扩散到外部介质中。
氢氧化钙提高了外部介质的pH值，对冠内漂白后的pH碱化有效。
根管治疗牙齿的冠内漂白可能会导致颈段牙根吸收。对此过程的一种可能解释是漂白剂进入牙周组织引发炎症过程。为了保持牙周pH值的中性，推荐使用氢氧化钙。本研究结果表明，这种材料应始终在冠内漂白后使用。
