Almeida Junior Lauber Jose Dos Santos, Lula Estevam Carlos de Oliveira, Penha Karla Janilee de Souza, Correia Vinicius Souza, Magalhães Fernando Augusto Cintra, Lima Darlon Martins, Firoozmand Leily Macedo
Department of Dentistry I, UFMA - Universidade Federal do Maranhão, São Luís, MA, Brasil.
Program in Public Health, UFMA - Universidade Federal do Maranhão, São Luís, MA, Brasil.
Braz Dent J. 2018 May-Jun;29(3):261-267. doi: 10.1590/0103-6440201801838.
The present study aimed to evaluates polymerization shrinkage (PS) using microcomputed tomography (μCT) and microtensile bond strength (μTBS) in bulk fill composites (BFC) and conventional class I restorations as well as the correlation between these factors. Class I cavities (4 x 5 x 4 mm), factor-C = 4.2, were created in third molars that were free of caries, which were randomly divided in 4 groups (n = 6): XTI (Filtek Supreme XTE: incremental technique); XTB (Filtek Supreme XTE: single fill technique); TBF (Tetric Bulk Fill); and SF (SonicFill). Each tooth was scanned twice in μCT: T0 was after filling the cavity with composite, and T1 was after light curing. The data were analyzed by subtracting the composite volume for each time (T1 - T0). After 1 week, the teeth were sectioned crosswise in the buccolingual and mesiodistal directions to obtain specimens with approximately 1 mm² thickness and fixed in a universal testing machine to perform μTBS. The Kruskal-Wallis and Dunn tests showed a statistically significant difference for shrinkage in µCT among the XTI and XTB and between the SF and XTB. Regarding the μTBS, all the groups differed from XTB. Bulk fill composites type presents a PS similar to that of the conventional nanoparticulate composite inserted using the incremental technique, but the bond strength was higher for the incremental group, which presented a lower number of pre-test failures when compared to BFC. No correlation was observed between the polymerization shrinkage and bond strength in the studied composites.
本研究旨在使用微型计算机断层扫描（μCT）评估大块充填复合材料（BFC）和传统I类修复体中的聚合收缩（PS）以及微拉伸粘结强度（μTBS），并评估这些因素之间的相关性。在无龋的第三磨牙中制备I类洞形（4×5×4mm，系数C = 4.2），将其随机分为4组（n = 6）：XTI（Filtek Supreme XTE：分层技术）；XTB（Filtek Supreme XTE：一次性充填技术）；TBF（Tetric Bulk Fill）；和SF（SonicFill）。每颗牙齿在μCT中扫描两次：T0为用复合材料充填窝洞后，T1为光固化后。通过减去每次的复合材料体积（T1 - T0）来分析数据。1周后，将牙齿在颊舌向和近远中向进行横向切片，以获得厚度约为1mm²的标本，并固定在万能试验机上进行μTBS测试。Kruskal-Wallis和Dunn检验显示，XTI和XTB之间以及SF和XTB之间在μCT收缩方面存在统计学上的显著差异。关于μTBS，所有组与XTB均不同。大块充填复合材料类型的PS与使用分层技术插入的传统纳米颗粒复合材料相似，但分层组的粘结强度更高，与BFC相比，其预测试失败次数更少。在所研究的复合材料中，未观察到聚合收缩与粘结强度之间存在相关性。
