Aksel Hacer, Askerbeyli-Örs Sevinc, Deniz-Sungur Derya
DDS, PhD, Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey.
DDS, Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey.
J Clin Exp Dent. 2017 Feb 1;9(2):e178-e181. doi: 10.4317/jced.53121. eCollection 2017 Feb.
The aim of the study is to evaluate the resistance vertical root fracture (VRF) of mineral trioxide aggregate (MTA) filled-immature permanent roots by using three different vehicles.
Forty-extracted human single-rooted mandibular premolars were selected and the root length was standardized to the length of 9 mm. For simulation of immature tooth apices, peeso reamers were introduced into the root canals and the prepared roots were assigned into three experimental groups according the used vehicle (distilled water-DW, prophylene glycol-PG, chlorhexidine-CHX) and control group (n=10). To simulate a periodontal membrane, the apical 7 mm of all roots was covered with wax to obtain a 0.2- to 0.3-mm-thick layer before embedding the roots into acrylic cylinders. A vertical force was applied (1mm/min) using a universal testing machine and the maximum load (F-max) that fracture occurred and the fracture mode (splint or comminuted) was recorded. Data were presented as mean and standard deviations. Statistical analysis was performed using Kruskal-Wallis, Mann-Whitney U Test was used for multiple comparisons.
There were significant differences between fracture strength of experimental groups with that of control group (<0.05). However, no statistically significant differences were found amongst the fracture strength values of the experimental groups (>0.05). In all groups, split fracture was the most common fracture mode.
MTA increases resistance of immature permanent teeth to VRF. Based on the results of this study, it can be concluded that mixing MTA with CHX or PG as the vehicle do not alter VRF resistance of simulated immature permanent roots. Immature teeth, MTA, vehicle, vertical root fracture.
本研究旨在评估使用三种不同载体时，矿物三氧化物凝聚体（MTA）充填的未成熟恒牙牙根对垂直根折（VRF）的抗力。
选取40颗拔除的人单根下颌前磨牙，将牙根长度标准化为9mm。为模拟未成熟牙的根尖，将梨形根管扩大钻插入根管，根据所使用的载体（蒸馏水-DW、丙二醇-PG、洗必泰-CHX）将制备好的牙根分为三个实验组和一个对照组（n = 10）。为模拟牙周膜，在将牙根嵌入丙烯酸圆柱体之前，用蜡覆盖所有牙根根尖7mm，以获得0.2至0.3mm厚的一层。使用万能试验机施加垂直力（1mm/分钟），记录发生骨折时的最大负荷（F-max）和骨折模式（夹板型或粉碎型）。数据以平均值和标准差表示。采用Kruskal-Wallis检验进行统计分析，使用Mann-Whitney U检验进行多重比较。
实验组与对照组的骨折强度之间存在显著差异（<0.05）。然而，实验组的骨折强度值之间未发现统计学上的显著差异（>0.05）。在所有组中，劈裂骨折是最常见的骨折模式。
MTA可增加未成熟恒牙对VRF的抗力。基于本研究结果，可以得出结论，将MTA与CHX或PG作为载体混合不会改变模拟未成熟恒牙牙根对VRF的抗力。未成熟牙、MTA、载体、垂直根折。
