研發新型可溶於尤加利油之熱塑性聚胺酯材料用於牙科根管封填

Development of Novel Eucalyptol-dissolved Thermoplastic Polyurethane Materials for Dental Root Canal Obturation

黃聖文(Sheng-Wun Huang)

指導教授 ： 林俊彬

國立臺灣大學/醫學院/臨床牙醫學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202101885

摘要

理想的根管封填錐體必須具備容易放置、體積穩定不會收縮、良好的生物相容性以及能夠容易被移除等條件。馬來膠(gutta-percha, GP)大體上合乎理想材料的要件，然而，研究顯示馬來膠其機械強度不足，且在加熱冷卻後易發生體積收縮，無法提供良好的根管系統密封性，並與各類封填劑及牙本質(dentin)間有黏著力不足的問題。本研究團隊過去已研發出熱塑性聚胺酯(thermoplastic polyurethane)錐體(cone)，有優於馬來膠的操作及機械性質，並且與胺酯壓克力樹酯封填劑及牙本質間的黏著有優於傳統封填材料的表現，但卻面臨難以將材料移除的問題。臨床上最常使用也公認相對安全的溶劑就是尤加利油(Eucalyptus oil)，因此本實驗的目的為調整製程，研發出新型可溶於尤加利油之熱塑性聚胺酯材料用於根管封填。
本實驗以先前研究團隊合成出的熱塑性聚胺酯原料為基礎，並嘗試使用與尤加利油結構相似的異山梨醇(D-Isosorbide)作為鏈延長劑(chain extender)，合成出不同硬鏈段的熱塑性聚胺酯，測試是否有溶解於尤加利油中的能力，並測試其熱性質及機械性質，從中選出最適合的硬鏈段比組合後，添加不同比例之氧化鋅作為填料(filler)，並探討添加氧化鋅後是否會影響熱塑性聚胺酯其溶解力、熱性質以及機械性質，也探討其細胞毒性及抗菌性質，並與馬來膠比較。
結果顯示以異山梨醇作為鏈延長劑所合成出的熱塑性聚胺酯有溶解於尤加利油的能力，也具有良好的熱穩定性，其中硬鏈段比30%的熱塑性聚胺酯擁有極佳的成膜性、最大拉力值以及延展性，熔點也與馬來膠相似；而添加氧化鋅後溶解效果並無明顯變化，卻會降低熱塑性聚胺酯的熱穩定性及機械性質；在生物測試方面也產生較高的細胞毒性，也無產生明顯抑菌圈。因此，在未來可以以異山梨醇這個原料為基礎，在製程上再做調整，期望合成出溶解度更好更接近Grossman 所提出的理想封填材料。

關鍵字

牙科根管封填 ； 熱塑性聚胺酯 ； 尤加利油 ； 根管封填錐體

並列摘要

The ideal root canal cone materials must fulfill the requirements such as easy placement, no shrinkage, good biocompatibility, and being removed easily. Gutta-percha (GP) has been widely used and generally meets the requirements as an ideal root canal cone material. However, studies have shown that it has poor mechanical strength and is prone to volume shrinkage after heating and cooling, which cannot provide a good sealing ability to the root canal system. More importantly, GP has no adhesion to sealers and dentin. Our research team has developed thermoplastic polyurethane (TPU) cone, which has better handling and mechanical properties than GP. It also has better adhesion to urethane acrylic sealers and dentin than traditional ones. Nevertheless, we still encountered the problem of difficulty in removing the material after sealing. The most commonly used and relatively safe solvent in clinical practice is eucalyptus oil. Therefore, the purpose of this experiment was to adjust the process to develop a new type of thermoplastic polyurethane material that could be dissolved in eucalyptus oil for root canal obturation.
This experiment was based on the thermoplastic polyurethane raw materials synthesized by our research team and tried to use D-Isosorbide, which has a similar structure to eucalyptus oil, as a chain extender to synthesize a TPU with different proportion of hard and soft segments. We also tested the ability of the materials to dissolve in eucalyptus oil and their thermal and mechanical properties. After selecting the most suitable ratio of hard and soft segments, we added different proportions of zinc oxide as a filler and examined whether zinc oxide would affect the solubility, thermal properties, and mechanical properties of the TPU. The cytotoxicity and antibacterial properties of the TPU were also discussed and compared with the GP.
The results showed that the TPU materials synthesized with D-Isosorbide as a chain extender could dissolve in eucalyptus oil and had good thermal stability. Among them, the hard and soft segments ratio of 30% TPU had the best mechanical properties and excellent film formation. The melting point was also similar to GP. The dissolution effect did not change significantly after adding zinc oxide, but it would reduce the thermal stability and mechanical properties of the TPU. In the biological test, adding zinc oxide to TPU showed higher cell cytotoxicity and no obvious inhibition zone. Therefore, in the future, we can use D-isosorbide as raw material and adjust the synthetical process, hoping to produce a better solubility and closer to the ideal filling material proposed by Grossman.

並列關鍵字

Root canal obturation ； Thermoplastic polyurethane ； Eucalyptus Oil ； Cone

參考文獻

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