Singh Ankita, Garg Sandeep
Postgraduate Student, Department of Prosthodontics, Crown and Bridge, MM College of Dental Sciences and Research , Mullana, Ambala, Haryana, India .
Professor and Head, Department of Prosthodontics Including Crown and Bridge, MM College of Dental Sciences and Research , Mullana, Ambala, Haryana, India .
J Clin Diagn Res. 2016 Aug;10(8):ZC72-7. doi: 10.7860/JCDR/2016/19582.8291. Epub 2016 Aug 1.
Provisional restorations serve a key role as a functional and esthetic try-in for the design of the final prosthesis. During selection of materials for this restoration, clinicians must consider physical properties, ease of handling, cost and patient satisfaction and approval.
To evaluate and compare the flexural strength of provisional crown and bridge materials available commercially.
This in-vitro study was done to compare the flexural strength of six temporary crown and bridge materials available commercially at 24 hours, 8 days and after repair. Three poly methyl methacrylate based materials (DPI, SC10 and Trulon) and three bis-acrylic based composite resins (Protemp, Cooltemp and Luxatemp) were selected. A total of 72 specimens of dimensions 64mm×10mm×2.5mm were prepared from these materials (12 from each material) and divided into two groups (n=36). Specimens were stored in artificial saliva and were fractured after 24 hours and 8 days using Universal Testing Machine. The fractured samples from the 8 days study were then subjected to repair. A uniform space of 2mm and a 450 bevel was maintained for all the repaired samples for better distribution of forces. Flexural strength of these repaired samples was recorded using the same machine. RESULTs were recorded and statistically analysed by one-way Anova and Post hoc tests.
RESULTs revealed that there was decrease in flexural strength for all the materials tested from 24 hours to 8 days, though flexural strength between poly methyl methacrylate and bis-acrylic resins was similar at 24 hours and 8 days time interval. A substantial decrease was noticed in the strength of bis-acrylic composite resins after repair.
From the current study it can be suggested that though there is decrease in flexural strength for all the materials from 24 hours to 8 days, both can be used to fabricate the provisional restorations. However, in the event of a fracture of a bis-acrylic provisional restoration, it may be more advantageous to make a new provisional restoration than to repair the fractured one.
临时修复体在最终修复体设计的功能和美学试戴方面起着关键作用。在为这种修复体选择材料时，临床医生必须考虑物理性能、操作简便性、成本以及患者的满意度和认可度。
评估和比较市售临时冠桥材料的抗弯强度。
本体外研究旨在比较6种市售临时冠桥材料在24小时、8天及修复后的抗弯强度。选用了3种聚甲基丙烯酸甲酯基材料（DPI、SC10和Trulon）和3种双丙烯酸基复合树脂（Protemp、Cooltemp和Luxatemp）。从这些材料中制备了总共72个尺寸为64mm×10mm×2.5mm的样本（每种材料12个），并分为两组（n = 36）。样本储存在人工唾液中，24小时和8天后使用万能试验机使其断裂。然后对8天研究中断裂的样本进行修复。为使力更好地分布，所有修复样本均保持2mm的均匀间隙和45°斜面。使用同一台机器记录这些修复样本的抗弯强度。记录结果并通过单因素方差分析和事后检验进行统计学分析。
结果显示，所有测试材料从24小时到8天抗弯强度均有所下降，不过在24小时和8天的时间间隔内，聚甲基丙烯酸甲酯和双丙烯酸树脂之间的抗弯强度相似。修复后双丙烯酸复合树脂的强度显著下降。
从当前研究可以看出，尽管所有材料从24小时到8天抗弯强度都有所下降，但两者均可用于制作临时修复体。然而，如果双丙烯酸临时修复体发生断裂，制作新的临时修复体可能比修复断裂的修复体更具优势。
