A Study on the Application to the Pulp Capping Agent of a DNA Film

目前，氢氧化钙髓内切开术广泛应用于一般临床治疗，牙本质桥的形成被认为是其成功的标志。然而，由于氢氧化钙是一种强碱，有报道称它会导致牙髓组织大面积坏死。此外，牙本质桥等新的硬组织的形成被认为表明牙髓受到了毒性刺激。如果牙髓组织可以通过使用生物相容性材料以更小的损伤保存，这将被认为是非常重要的。因此，我们研究了人工脂质修饰DNA的使用，据报道，这种材料具有中等可生物降解性、非抗原性和抗菌性。福岛等研究表明，人工脂质修饰DNA是一种很有前途的可生物降解生物材料，有望应用于牙科。在这项研究中，我们评估了它作为牙髓切开术后牙髓包扎材料的使用。由于初步实验发现DNA膜本身的可操控性存在问题，我们将未包被和DNA包被的羟基磷灰石应用于比格犬双侧上、下犬牙的切髓表面，并通过组织病理学检查牙髓组织的变化。经dna包被羟基磷灰石处理的牙髓中，炎症细胞浸润和钙化较未包被羟基磷灰石处理的牙髓轻。这些发现表明DNA对牙髓组织没有毒性，甚至表现出抗炎活性。此外，由于DNA可以嵌入抗生素和成骨诱导剂，它可能在未来应用作为牙髓敷料剂。

Presently, vital pulpotomy using calcium hydroxide is widely performed in general clinical treatment, and dentin bridge formation is considered an indication of its success. However, since calcium hydroxide is a strong alkali, it has been reported to cause extensive necrosis in pulp tissue. Furthermore, the formation of new, hard tissue such as a dentin bridge is considered to indicate that toxic stimulation has been applied to the pulp. If pulp tissue could be preserved with less damage through the use of a biocompatible material, it would be considered to be extremely significant. Therefore, we investigated the use of artificial lipid-modified DNA, which has been reported to be moderately biodegradable, non-antigenic, and antibiotic, as such a material. Fukushima et al. showed that artificial lipid-modified DNA is a promising biodegradable biological material, and it is expected to be applied to dentistry. In this study, we evaluated its use as a pulp dressing material after vital pulpotomy. Since preliminary experiments revealed problems with the manipulability of DNA film itself, we applied uncoated and DNA-coated hydroxyapatite to pulpotomy surfaces of the bilateral upper and lower canine teeth in beagles and histopathologically examined pulp tissue changes. In the pulp treated with DNA-coated hydroxyapatite, inflammatory cell infiltration and calcification were milder than in those treated with uncoated hydroxyapatite. These findings suggest that DNA is not toxic to pulp tissue and even exhibits an anti-inflammatory activity. Moreover, as DNA can intercalate antibiotics and osteogenesis inducers, it may be applied in the future as a pulp dressing agent.