Cintra Luciano Tavares Angelo, Benetti Francine, Ferreira Luciana Lousada, Rahal Vanessa, Ervolino Edilson, Jacinto Rogério de Castilho, Gomes Filho João Eduardo, Briso André Luiz Fraga
Departamento de Endodontia, Faculdade de Odontologia de Araçatuba, Univ. Estadual Paulista, Araçatuba, SP, Brasil.
Departamento de Odontologia Restauradora, Faculdade de Odontologia de Araçatuba, Univ. Estadual Paulista, Araçatuba, SP, Brasil.
J Appl Oral Sci. 2016 Jan-Feb;24(1):95-104. doi: 10.1590/1678-775720150393.
Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents.
To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth.
The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05).
After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas.
The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.
一般来说，牙科材料在用于人类临床之前会在不同动物模型中进行测试，但漂白剂除外。
通过研究过氧化氢凝胶不同浓度和应用时间对大鼠活髓牙诊室漂白期间牙髓组织的影响，评估一种用于漂白剂比较研究的实验大鼠模型。
50只Wistar大鼠的右上颌和左上颌磨牙分别用20%和35%的过氧化氢凝胶漂白5、10、15、30或45分钟（每组n = 10只大鼠）。10只动物（对照组）未接受处理。在2天或30天后处死大鼠，对上颌骨进行光学显微镜检查。通过组织形态计量分析评估炎症，在牙髓冠部和根部三分之一处计数炎症细胞。还进行成纤维细胞计数。对成牙本质细胞层和血管变化进行评分。组织形态计量测量第三期牙本质面积和牙髓腔中心面积。通过方差分析和Kruskal-Wallis检验比较数据（p<0.05）。
2天后，两种浓度漂白凝胶在15分钟时，牙髓冠部咬合面三分之一处的炎症细胞数量增加。在每个浓度的30分钟和45分钟组中，炎症细胞数量减少，同时出现坏死区域。30天后，观察到牙髓腔中心面积减小，第三期牙本质面积增大，未检测到炎症区域。
冠外漂白大鼠模型适用于漂白方案研究，因为可以观察到不同浓度和应用时间的漂白剂对牙髓组织和牙齿结构的改变。
