三氧礦化聚合物與鑄造金屬根柱接觸面交互作用之初步研究

A Preliminary Study on the Interaction of the Interfaces between Mineral Trioxide Aggregate and Casting Post Alloy

隨著微創牙醫學的觀念日趨盛行，保留齒質的術式及保存牙齒的技術也蓬勃發展，透過牙髓病手術保留自然牙的臨床需求亦日益增加，衍伸牙髓病手術時所使用的根尖逆充填材料可能與根柱金屬直接接觸的機會相對提高。臨床上三氧礦化聚合物（Mineral Trioxide Aggregate, MTA）是最常使用的根尖逆充填生醫材料，因此本研究設計模擬牙髓病手術時，MTA與根柱鑄造金屬直接接觸，觀察接觸介面之形貌改變。結果顯示MTA-根柱鑄造金屬之接觸介面，在三十天的觀察期，隨時間增加，在金屬表面出現面積逐漸增大類似腐蝕的表面粗糙度變化之形貌，同時在MTA及金屬表面均可觀察到顏色改變之顆粒堆積的現象。臨床上MTA與鑄造金屬接觸介面發生形貌與表面粗糙度變化的位置，並未與牙周及根尖組織直接接觸，但是MTA與根柱鑄造金屬因直接接觸所形成的顆粒其微觀分析，以及是否影響長期臨床治療的預後，均有待更進一步的探討研究。本研究透過長時間直接觀察MTA直接與根柱鑄造金屬接觸介面的形貌變化結果，建議牙醫師進行牙髓病手術時，在選擇使用根尖逆充填材料時應同時兼顧根柱的材料成份。

This preliminary experiment evaluated the impact of cobalt chrome prosthetic post alloy on corrosion behavior when coupled with mineral trioxide aggregate (MTA) in an in vitro model. Due to increasing the demand for tooth preservation and the success of minimally-invasive dentistry and microscope-assisted endodontics, there has been a significant improvement. More teeth with clinical symptoms are now undergoing endodontic surgery. Simultaneously, MTA has been widely utilized in the field of endodontics as a retrograde filling material over the last two decades with numerous studies confirming its contribution to increased success rates in endodontic surgery. However, there is limited information on the interaction of interfaces between MTA and prosthetic post alloy. Therefore, we investigated the macroscopic surface changes at the interface for MTA-alloy. Specimens were prepared and divided into two groups: 20 tested specimens from cobalt-chrome alloys immersed in MTAs and 5 specimens in the negative control group, consisting of cobalt-chrome alloys and MTAs individually without contact. All specimens were incubated in a 37°C incubator. After 30 days, visual observation and dental microscope evaluation were conducted to examine color changes, surface morphology, particle accumulation, and metal corrosion of the MTA-alloy interface. The surfaces of the alloy and the MTA of the negative control groups were also examined. The result demonstrated that the tested specimens exhibited color changes, morphologic roughness, and pitting corrosion. However, considering the potential tissue irritation from the MTA-alloy interface when released into the periradicular area, it appears more appropriate for clinicians to carefully consider retrograde filling material selection in endodontic surgery, avoiding MTA direct coverage of the post alloy.