聚醚醚酮/矽酸鈣複合材料之機械性質與生物降解性

聚醚醚酮 (Polyetheretherketone, PEEK) 因為無毒性、具有化學穩定性以及機械性能，已被廣泛應用於牙科植體及椎間融合器 (Interbody spacers) 。雖然它的彈性係數與人類皮質骨相近，但仍有改善空間，這一項不足可透過加入無機填料來調整。矽酸鈣 (Calcium silicate) 材料具有成骨 (Osteogenic) 性質，被用於骨修復和再生。本研究使用生物活性矽酸鈣來改善PEEK的彈性係數和生物惰性 (Bio-inertness)。將PEEK與矽酸鈣顆粒按照體積比9:1、8:2和7:3混合，分別命名為9P1CS、8P2CS和7P3CS，隨後進行370 ℃、380 ℃或390 ℃燒製。除了表面性質和生物降解性分析，還對複合材料的機械性質進行了抗壓、拉伸和三點彎曲測試。結果顯示，矽酸鈣填料在PEEK基質中分佈均勻，燒製提高PEEK的結晶度。在所有複合材料中均檢測到2θ位於32˚至34˚β-Ca2SiO4繞射峰，是矽酸鈣存在的證據。機械性質方面，經370 ℃、380 ℃和390 ℃燒製後，8P2CS組的抗壓強度分別為140 MPa、154 MPa和132 MPa；380 ℃燒製的9P1CS、8P2CS和7P3CS拉伸強度分別為89 MPa、54 MPa和35 MPa；三點彎曲強度同樣隨矽酸鈣含量的增加而降低。然而經380 ℃燒製後，8P2CS組的三點彎曲彈性係數 (4.9 GPa) 高於純PEEK (2.2 GPa)。浸泡於模擬體液12個月後，SEM顯示7P3CS組在pH 7.4溶液內長出氫氧基磷灰石，和XRD及FTIR結果一致，且浸泡後三點彎曲強度不減反增，推測為矽酸鈣水合硬化作用所導致。總結來說，經380 ℃燒製的8P2CS組可能適用於功能性咬合應用。

Poly-ether-ether-ketone (PEEK) has been widely used in dental implants and interbody spacers due to its non-toxicity, chemical stability, and mechanical properties. Although its modulus of elasticity is similar to that of human cortical bone, there is still room for improvement. This shortcoming can be fine-tuned by introducing inorganic fillers. Calcium silicate materials have been used for bone repair and regeneration due to their osteogenic properties. In this study, bioactive calcium silicate was used to improve the elasticity modulus and bio-inertness of PEEK. The PEEK and calcium silicate particles were mixed by volume ratios of 9:1, 8:2, and 7:3, which were named 9P1CS, 8P2CS, and 7P3CS, respectively, followed by heat treatment at 370 ℃, 380 ℃, or 390 ℃. In addition to surface properties and biodegradability, the mechanical properties of the composites were examined under compression, tensile, and three-point bending modes. The results indicated that calcium silicate fillers were well-distributed within the PEEK matrix, and the heat treatment increased the crystallinity of PEEK. Diffraction peaks of β-Ca2SiO4 were detected at 2θ values between 32˚ and 34˚ in all composites, indicating the presence of calcium silicate. Regarding the mechanical properties, the compressive strength of the 8P2CS group after heat treatment at 370, 380, and 390 ℃ were 140, 154, and 132 MPa, respectively. The tensile strengths of the 380 ℃-treated 9P1CS, 8P2CS, and 7P3CS groups were 89, 54, and 35 MPa. Similarly, three-point bending strength values decreased with the increase in the content of calcium silicate. However, a higher three-point bending elastic modulus was obtained in the 380 ℃-treated 8P2CS group (4.9 GPa) than in pure PEEK (2.2 GPa). After 12 months of soaking in simulated body fluid (SBF) at pH 7.4, scanning electron microscopy (SEM) observation revealed the precipitation of hydroxyapatite on the 7P3CS group, consistent with the X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) results. Additionally, the three-point bending strength increased after soaking, likely due to the hardening effect of calcium silicate. In summary, the 8P2CS group treated at 380 ℃ may be a suitable candidate for functional occlusal applications.