Graduate Program in Dentistry, Universidade Federal de Sergipe, Aracaju, SE, Brazil.
Department of Dentistry, Associação Caruaruense de Ensino Superior, Caruaru, PE, Brazil.
Braz Oral Res. 2020;34:e111. doi: 10.1590/1807-3107bor-2020.vol34.0111. Epub 2020 Aug 28.
This study evaluated the effect of selective carious tissue removal on the fracture strength and failure mode of composite restorations in molars presenting only the buccal cusps. Deep cavities were prepared on the occlusal surface, and the lingual cusps were removed. Carious lesions in the middle of the pulpal wall were artificially induced with acetic acid (pH = 4.5) for 35 days. The demineralized dentin was left intact or was completely removed prior to restoration with a bulk-fill composite (n = 10). Images of the specimens were obtained by optical coherence tomography (OCT) before and after the caries induction/removal. The mechanical resistance to fracture by axial compressive loading and the failure type and extension were determined. The pulpal wall/composite interface of the fractured specimens was analyzed by OCT. The data were analyzed for significance with t-tests (α = 0.05). The deepest cavities and a more frequent occurrence of pulpal exposure were observed more often for non-selective carious tissue removal. The protocol of carious tissue removal did not affect the fracture strength (p = 0.554). An increased occurrence of catastrophic failures involving the roots was observed for non-selective carious tissue removal. Some occurrences of restoration displacement or cracks throughout the resin-dentin were observed only for the selective carious tissue approach. Selective carious tissue removal is a feasible approach to extensively damaged teeth since it reduced the occurrence of pulpal exposure and root fractures, without compromising the fracture strength.
本研究评估了选择性去除龋坏组织对仅颊尖存在龋损的磨牙复合树脂修复体的断裂强度和失效模式的影响。在咬合面制备深窝洞，并去除舌尖。用乙酸（pH = 4.5）在牙髓壁中部人工诱导龋损 35 天。在使用大体积充填型复合树脂进行修复之前，保留或完全去除脱矿牙本质（n = 10）。在龋病诱导/去除前后，通过光相干断层扫描（OCT）获得标本的图像。通过轴向压缩加载确定断裂阻力和失效类型及扩展。用 OCT 分析断裂标本的牙髓壁/复合界面。用 t 检验（α = 0.05）分析数据的显著性。非选择性去除龋坏组织时，观察到最深的窝洞和更频繁的牙髓暴露。龋坏组织去除方案不影响断裂强度（p = 0.554）。非选择性去除龋坏组织时，更频繁地发生累及根的灾难性失效。仅选择性去除龋坏组织时，观察到一些树脂-牙本质的移位或贯穿整个树脂-牙本质的裂纹。选择性去除龋坏组织是一种可行的方法，因为它减少了牙髓暴露和根折的发生，而不会影响断裂强度。
