A comparison of stresses in molar teeth restored with inlays and direct restorations, including polymerization shrinkage of composite resin and tooth loading during mastication
A comparison of stresses in molar teeth restored with inlays and direct restorations, including polymerization shrinkage of composite resin and tooth loading during mastication
复制标题
DOI：
10.1016/j.dental.2014.11.016
复制
发表时间：
2015-03-01
期刊：
影响因子：
5
通讯作者：
Mlotkowski, Andrzej
中科院分区：
文献类型：
--
作者：
Dejak, Beata;Mlotkowski, Andrzej
复合材料的聚合收缩是造成牙体周围渗漏的主要原因之一。尽管有大量的研究没有达成共识，什么样的牙齿重建-直接或间接复合修复是最有益的和最持久的。目的是比较模拟咀嚼过程中嵌体修复和直接修复（考虑复合树脂聚合收缩）后磨牙II类MOD洞的等效应力和接触粘结应力。研究采用有限元法，并应用接触单元。建立了三个第一磨牙的3D模型：模型A是完整的牙齿;模型B是复合嵌体的牙齿，模型C是直接复合修复的牙齿。聚合线性收缩0.7%的直接复合材料修复和树脂粘接水泥模拟（负载1）。进行咀嚼的计算机模拟（负荷2）。在这两种情况下，根据修正的vonMises准则（mvM），计算并比较不同牙弓高度的下颌第一磨牙模型材料的等效应力。同时对牙体组织粘接剂-粘接剂界面的接触应力进行了分析。直接复合材料修复的牙齿（其整个体积受到聚合收缩的影响）中的等效应力比复合材料嵌体修复的牙齿（其中收缩仅存在于一薄层胶合剂中）高出许多倍。牙本质和牙釉质的应力值比嵌体高8-14倍，直接修复体的应力值比嵌体高13倍。同样，直接修复体周围的粘合剂粘合中的接触应力比口腔外固化修复体高6.5-7.7倍。在咀嚼模拟实验中，直接复合修复体周围粘结层的剪切接触应力达到最大值32.8 MPa，明显超过树脂粘结剂与牙体结构连接处的剪切强度。嵌体修复的牙齿结构中的等效应力和修复材料本身中的等效应力以及牙齿-粘接剂粘接界面处的接触应力比直接复合材料修复的牙齿低许多倍。与直接修复的牙齿相比，间接修复的牙齿可能不太容易受到损伤。复合嵌体也确保了更好的密封相比，直接双眼皮。聚合收缩决定了直接修复牙的应力水平，而它对间接修复牙的粘附力的影响是微不足道的。(C)2014年牙科材料学院。由爱思唯尔有限公司出版。保留所有权利。
Polymerization shrinkage of composites is one of the main causes of leakage around dental restorations. Despite the large numbers of studies there is no consensus, what kind of teeth reconstruction-direct or indirect composite restorations are the most beneficial and the most durable.Objective. The aim was to compare equivalent stresses and contact adhesive stresses in molar teeth with class II MOD cavities, which were restored with inlays and direct restorations (taking into account polymerization shrinkage of composite resin) during simulated mastication.Method. The study was conducted using the finite elements method with the application of contact elements. Three 3D models of first molars were created: model A was an intact tooth; model B-a tooth with a composite inlay, and model C a tooth with a direct composite restoration. Polymerization linear shrinkage 0.7% of a direct composite restoration and resin luting cement was simulated (load 1). A computer simulation of mastication was performed (load 2). In these 2 situations, equivalent stresses according to the modified von Mises criterion (mvM) in the materials of mandibular first molar models with different restorations were calculated and compared. Contact stresses in the luting cement-tooth tissue adhesive interface around the restorations were also assessed and analyzed.Results. Equivalent stresses in a tooth with a direct composite restoration (the entire volume of which was affected by polymerization shrinkage) were many times higher than in the tooth restored with a composite inlay (where shrinkage was present only in a thin layer of the luting cement). In dentin and enamel the stress values were 8-14 times higher, and were 13 times higher in the direct restoration than in the inlay. Likewise, contact stresses in the adhesive bond around the direct restoration were 6.5-7.7 times higher compared to an extraorally cured restoration. In the masticatory simulation, shear contact stresses in the adhesive bond around the direct composite restoration reached the highest values 32.8 MPa and significantly exceeded the shear strength of the connection between the resin luting cement and the tooth structure.Signcance. Equivalent stresses in the tooth structures restored with inlays and in the restoration material itself and contact stresses at the tooth-luting cement adhesive interface are many times lower compared to teeth with direct composite restorations. Teeth with indirect restorations are potentially less susceptible to damage compared to those with direct restorations. Composite inlays also ensure a better seal compared to direct restorations. Polymerization shrinkage determines stress levels in teeth with direct restorations, while its impact on adhesion in indirectly restored teeth is insignificant. (C) 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.