開發具有高硬度及彎曲強度、低收縮率新型複合樹脂

Development of a new composite resin with clinical need-low shrinkage, high hardness, high flexural strength.

曾柏翰(Bo-Han Zeng)

指導教授 ： 李伯訓 ； 楊宗傑

國立臺灣大學/醫學院/口腔生物科學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202004241

摘要

樹脂是目前牙科中最常使用的修復材料，具有許多的優點例如：顏色與牙齒相近、操作簡易、成本低廉。但是也存在著許多的缺點，例如：耐磨耗強度不如汞合金堅固、聚合收縮、邊緣變色等。複合樹脂主要由有機單體和無機填料依照不同比例所混合而成。常見的樹脂有：PMMA、Bis-GMA、EBPDMA、UDMA、TEGDMA等。不同的樹脂依照不同的分子量、不同的結構式有著不一樣的特性。而分子量大收縮小的丙烯酸樹脂，如雙酚A丙三醇雙甲基丙烯酸酯 (Bis-GMA)，常被使用作為樹脂基質，但這類樹脂的高黏度特性，使得無機填料的添加量和轉化率受到限制，常會使用低分子量的單體，如：TEGDMA常被用來當作稀釋劑，用來降低黏稠度，增加反應性、填料負載量和轉化率。然而，稀釋單體也會增加聚合收縮，產生收縮應力。導致牙齒交界面黏著失敗，邊緣變色，繼發性齲齒，術後牙齒敏感及牙髓發炎等問題。聚合收縮是造成臨床上複合樹脂填補失敗的主要原因。降低聚合收縮是目前臨床使用上的一項目標。
目前，臨床上仍未有「無收縮」的複合樹脂。單體的分子量和體積越大，聚合收縮就越小。複合樹脂最常使用的就是Bis-GMA和其衍生物。在本實驗中，我們使用新研發超分枝狀結構的單體 (HBPUA) 取代雙酚A丙三醇雙甲基丙烯酸酯 (Bis-GMA) ，並且依照不同的比例 (3:7及 6:4) 進行實驗分析，利用其超分枝狀的結構，改善其收縮率，收縮率從未添加HBPUA時的14.79 %，添加60 w% HBPUA時下降至2.3 %，並且不僅僅在收縮率上做突破，也將同時改善其硬度及彎曲強度。實驗中發現當添加到 60 w%的HBPUA，硬度達到 21.32 HV並且彎曲強度也達到87.12 MPa，這個比例能夠在硬度及彎曲強度中取得一個平衡，低於60 w%，則表現出硬度不足夠，但是有較佳的彎曲強度。目前本實驗所使用之樹脂可以有效減少收縮率並且增加硬度及彎曲強度，並且有較佳的生物相容性，未來可以於臨床牙科上作為牙科材料使用。

關鍵字

複合樹脂 ； 聚合收縮 ； 修復材料 ； 硬度 ； 彎曲強度

並列摘要

Resins are currently the most commonly used restorative material composite resin in dental restoration. It has many advantages such as similar color to teeth, easy to operate and low cost. But there are also many disadvantages, such as the low abrasion resistance, high polymerization shrinkage, edge discoloration, etc. Composite resins are mainly composed of organic monomers and inorganic fillers mixed in different ratio.Resins that are commonly use are: PMMA, Bis-GMA, EBPDMA, UDMA, TEGDMA,and etc. The different resins have different characteristics according to molecular weights and structural formulas. Acrylic resins with high molecular weight and low shrinkage, such as bisphenol A glycidyl methacrylate (Bis-GMA) , are often used as resin matrix. However, these resins have high viscosity. It which result in the limitation of the amount of inorganic fillers and the conversion rate. Therefore, Itis normally used as low molecular weight monomers. For example: TEGDMA is often used as a diluent to reduce viscosity, increase reactivity, increase filler loading and conversion, But the diluting monomer increases polymerization shrinkage and creates shrinkage stress.Caused by tooth interface failure adhesion, edge discoloration, secondary tooth decay,postoperative tooth sensitivity and pulp inflammation. Polymer shrinkage is the main reason causing failure of composite resin filling in clinical practice. Reducing polymerization shrinkage is a goal in clinics.
Recently, there is zero shrinkage composite in clinic. The larger the molecular
weight and volume of the monomer, the lower shrinkage. The most used composite
resins are Bis-GMA and its derivatives. In experiment, we replaced the bisphenol A glycidyl methacrylate (Bis-GMA) with a new composite resin (HBPUA), and tested with different ratio. Because the branched structure is can reduce the shrinkage while maintaining hardness and toughness. using its branched structure to improve its Shrinkage. And not only a breakthrough in shrinkage, will also improve its hardness and toughness. According to our experiment, adding to 60 w% of HBPUA, a balance can be achieved between hardness and bending strength. Below 60 w%, the hardness is not sufficient, but it has better toughness. The resin used in this experiment can fortunately reduce shrinkage and increase hardness and toughness. It has the potential to be used as a novel restoration material in dental clinics.

並列關鍵字

composite resin ； polymerization shrinkage ； restore materials ； hardness ； flexural strength

參考文獻

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