Evaluation of dentinogenesis inducer biomaterials: an in vivo study

Abstract When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. Objective: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. Methodology: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). Results: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of 99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. Conclusions: The mineral trioxide aggregate (WhiteProRoot®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications

摘要 当牙髓暴露于外界环境时，可通过直接盖髓术诱导修复性牙本质形成，以维持牙髓组织的活力与功能。此类临床场景需要使用可诱导牙本质修复、进而形成矿化组织的材料。目的：本研究旨在评估硅酸三钙水门汀与三氧化矿物凝聚体（mineral trioxide aggregate，MTA）水门汀的效果，包括牙髓暴露后不同时间点的牙本质修复形成与炎症反应，实验对象为Wistar大鼠。方法：将这两种生物材料与阳性对照组（开髓暴露牙髓）、阴性对照组（无干预）进行对比。评估分为三个时间阶段：术后3天、7天和21天，评估手段包括影像学（核医学）检测与组织学评估（苏木精-伊红（H&E）染色、免疫组化及茜素红S染色）。结果：证实了上述生物材料的治疗效果。核医学检测显示，99mTc-羟基亚甲基二膦酸盐（99mTc-Hydroxymethylene diphosphonate，HMDP）的摄取量在各实验组与对照组间无显著差异，表明磷钙代谢未出现明显差异。组织学研究显示，采用三氧化矿物凝聚体治疗的样本在术后3天可见中度炎症浸润，随随访时间推移逐渐减轻；矿化组织的形成仅在随访21天时得以证实。采用硅酸三钙治疗的样本在术后第3天可见轻度炎症浸润，随随访时间推移炎症有所加重；矿化组织的形成在术后第7天即可观察到，并随时间推移逐渐增加。结论：三氧化矿物凝聚体（WhiteProRoot®MTA）与硅酸三钙（Biodentine™）可在牙髓组织中引发轻度且可逆的炎症反应，并促成矿化组织形成。然而，硅酸三钙生物材料对矿化组织形成的过度诱导，可能会导致牙髓钙化。