Spectrophotometric analysis of tooth discolouration induced by mineral trioxide aggregate after final irrigation with sodium hypochlorite: An in vitro study

The aim of this study was to evaluate specific chromatic alterations induced by white mineral trioxide aggregate after final irrigation with sodium hypochlorite. Sixty specimens were prepared mechanically and filled with mineral trioxide aggregate after different final irrigation protocols: Group 1 – distilled water, Group 2 – sodium hypochlorite followed by distilled water, Group 3 – sodium hypochlorite, only. Colour changes were recorded with a spectrophotometer at baseline, and then after 1, 2 and 4 months. The Commision Internationale de l’éclairage colour system was used and the total colour changes ΔE were calculated. In groups where sodium hypochlorite was used, parameter L* decreased significantly after the first month (Group 2 (P < 0.006), Group 3 (P < 0.009)). Group 3 demonstrated greater colour change ΔE than Group 1, after the first month (P < 0.02). In conclusion, white mineral trioxide aggregate can lead to tooth discolouration by contact with sodium hypochlorite residues in dentinal tubules.     

云南民族院校学生智齿冠周炎临床资料分析

目的 比较云南民族院校少数民族学生和汉族学生智齿冠周炎复发率以及智齿阻生类型.方法选择549例民族院校学生智齿冠周炎病例,由口腔医生检查下颌智齿阻生类型、急性智齿冠周炎临床症状及复发情况,并进行统计学分析.结果下颌智齿垂直阻生引发的冠周炎最多(58.65%);少数民族学生和汉族学生智齿阻生类型差异无统计学意义(P>0.05);少数民族学生与汉族学生智齿冠周炎复发率间差异有统计学意义(P<0.01).结论民族院校学生智齿冠周炎的发病率和复发率较高.     

止血剂对乳牙牙本质黏结强度的影响

目的:探讨止血剂对乳牙牙本质黏结强度的影响.方法:选取40颗滞留乳磨牙,构建磨切后牙本质模型,随机分为观察组和对照组,每组20颗实验牙.观察组采用止血剂覆盖30 s后冲洗,然后进行黏结处理,对照组直接进行黏结处理.观察2组微拉伸黏结强度、微渗漏情况.采用SPSS 19.0软件包对数据进行统计学分析.结果:观察组微拉伸黏结强度为(12.84±2.10)MPa,显著低于对照组的(14.03±2.28)MPa(P＜0.05);观察组形成的树脂突大部分＞35 μm,且长而密集,伸入开放的牙本质小管中;对照组形成的树脂突长约7～35 μm,侧支交通明显;2组牙本质黏结剂的微渗漏程度比例差异无显著性(P＞0.05).结论:止血剂对乳牙牙本质黏结强度有一定影响,临床应用时应特别注意.     

免费龋齿充填干预对上海嘉定区学龄前儿童乳牙龋病的影响

目的:为上海市嘉定区儿童口腔预防工作提供基线资料,明确嘉定区儿童中浅度龋齿免费充填活动的效果.方法:使用整体抽样方法,对2所经济条件、生活环境相似的幼儿园中的918名儿童连续观察3 a.一所幼儿园连续3年免费充填中、浅度龋齿,一所幼儿园作为对照.采用SPSS20.0软件包对数据进行r检验.结果:基线时2所幼儿园患龋率、龋均(dft)、龋蚀严重度指数(CSI)均无显著差异.经过3年干预,2组幼儿园儿童患龋率、dft、CSI均有显著差异.经过3年干预,干预组幼儿患龋率(43.90％)、dft(2.86)、CSI(7.34)均显著低于对照组(64.08％、3.51、10.17).结论:免费充填干预提高了儿童龋病充填率,降低了患龋率、龋均、CSI,早期抑制了龋病的发展.     

Orthodontic management of a dilacerated central incisor and partially impacted canine with unilateral extraction – A case report

Aim

To align a dilacerated maxillary central incisor and partially impacted canine with unilateral extraction in a young patient with skeletal deep bite.