Huangfu Ruo-qi, Xu Xiao
Department of VIP Dentistry, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai 200011, China.
Shanghai Kou Qiang Yi Xue. 2011 Feb;20(1):26-30.
To investigate the influences of factors such as cavity depth,shape,restorative materials and occlusal adjustment on the restoration of non-carious cervical lesions(NCCL) in the first maxillary premolars.
3-D finite element models of adult first maxillary premolars which had cavities of different depths and shapes in buccal cervical region were built. The models were restored and divided into three groups: glass ion cement (GIC), amalgam and composite resin. The stress profiles and distribution in normal occlusion and malocclusion were evaluated from vertical to lateral loading.
In normal occlusion, there was mainly tensile stress and uniform distribution on the buccal cervical margin, compressive stress appeared when approaching to tooth root; in malocclusion, there was mainly greater concentrated tensile stress on the buccal cervical margin than normal occlusion. In all the two occlusions, lateral loading increased stress concentration and value comparing with vertical loading. The contrast between different cavity depths showed significant positive correlation between stress value of restoration and cavity depth. The wedge, rectangle and rounded shaped cavity in the cases of small cavities depths (0.5, 1.0mm) exhibited no difference. For larger cavity depth (1.5mm), the stress of rectangular cavity was greater than the wedge (about 4 times), but no difference between the wedge and the rounded. The interface stress value of GIC and composite resin model was smaller than that of amalgam the latter was 3-9 times greater than the former two. The GIC was slightly smaller than the resin (0.2-2.4 MPa).
For small cavity depth, cavity shape is not the primary factor affecting the treatment of NCCL. The rectangular cavity isn't suitable for large defect. There is positive correlation between stress value of restoration and cavity depth. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality(08DZ2271100).
探讨洞深、洞形、修复材料及咬合调整等因素对上颌第一前磨牙非龋性颈部病变（NCCL）修复的影响。
建立成年上颌第一前磨牙颊侧颈部具有不同深度和形状洞形的三维有限元模型。对模型进行修复并分为三组：玻璃离子水门汀（GIC）、银汞合金和复合树脂。从垂直加载到侧向加载评估正常咬合和错合时的应力分布和情况。
在正常咬合时，颊侧颈部边缘主要存在拉应力且分布均匀，靠近牙根时出现压应力；在错合时，颊侧颈部边缘主要存在比正常咬合时更大的集中拉应力。在两种咬合情况下，与垂直加载相比，侧向加载均增加了应力集中和应力值。不同洞深之间的对比显示修复体应力值与洞深呈显著正相关。在小洞深（0.5、1.0mm）情况下，楔形、矩形和圆形洞形之间无差异。对于较大洞深（1.5mm），矩形洞的应力大于楔形洞（约4倍），但楔形洞与圆形洞之间无差异。GIC和复合树脂模型的界面应力值小于银汞合金模型，后者比前两者大3 - 9倍。GIC略小于树脂（0.2 - 2.4MPa）。
对于小洞深，洞形不是影响NCCL治疗的主要因素。矩形洞不适合大的缺损。修复体应力值与洞深呈正相关。由上海市科学技术委员会科研基金资助（08DZ2271100）。
