Conservative Dentistry Department, Faculty of Dentistry, Cairo University, Cairo, Egypt.
National Institute of Standards (Engineering and Surface Metrology), Giza, Egypt.
BMC Oral Health. 2023 Aug 2;23(1):535. doi: 10.1186/s12903-023-03222-5.
Poor contact tightness and contour in class II composite restorations are significant problems in clinical practice. They affect occlusal stability and periodontal health. The aim of this study was to evaluate proximal contact tightness and contour established after completing class II direct composite restorations using two pre-contoured matrix systems.
Standardized mesio-occlusal cavities were prepared in twenty typodont lower right first permanent molar teeth. Prepared teeth were randomly divided into two groups according to matrix system: Group 1, Sectional matrix system with a separation ring (Palodent V3); and Group 2, Circumferential matrix system with integrated tightener (Palodent 360). Contact tightness was evaluated using universal testing machine. Area, depth and curvature radius of proximal surface concavity in the restoration were evaluated using contact stylus profilometer. T-test was used for comparison between groups.
Sectional matrix showed higher contact tightness than circumferential matrix system. The results of proximal surface concavity in the restoration showed significantly higher area and depth of concavity with lower radius of curvature in circumferential matrix compared to sectional matrix.
The use of separation ring with sectional matrix provides superior contact tightness compared to circumferential matrix. However, both matrix systems presented some deficiency regarding proximal contour of direct class II resin composite restoration.
在临床实践中，II 类复合修复体的接触密封性和形态不佳是一个重大问题。它们会影响咬合稳定性和牙周健康。本研究的目的是评估使用两种预成型的矩阵系统完成 II 类直接复合修复体后近中接触的密封性和形态。
在二十颗典型的右下第一恒磨牙上制备标准的近中-远中牙合面窝洞。根据使用的矩阵系统将预备好的牙齿随机分为两组：组 1，带分离环的分段式矩阵系统（Palodent V3）；组 2，带集成紧固器的环形矩阵系统（Palodent 360）。使用万能试验机评估接触密封性。使用接触式轮廓仪评估修复体近中面凹陷的面积、深度和曲率半径。使用 t 检验进行组间比较。
分段式矩阵的接触密封性优于环形矩阵系统。修复体近中面凹陷的结果显示，环形矩阵的凹陷面积和深度明显较高，曲率半径较低。
与环形矩阵相比，带分离环的分段式矩阵在接触密封性方面具有优势。然而，两种矩阵系统在直接 II 类树脂复合修复体的近中形态方面都存在一些不足。
