近年来, 齿科氧化锆陶瓷凭借高强韧性、良好生物相容性和美观自然色泽而成为牙齿临床修复的首选对象, 可用于修复、固定局部义齿和种植牙。然而, 在低温潮湿环境中氧化锆陶瓷易发生t-m相变老化, 服役寿命显著缩短, 严重影响其临床稳定性。本文综述了氧化锆陶瓷低温老化的特点、机制及其老化动力学规律, 并介绍了表征氧化锆低温老化现象的常规技术手段以及光学相干断层扫描、聚焦离子束等新方法; 总结了低温老化行为的主要影响因素以及抗老化措施, 具体可通过调整材料体系、改进加工方式等来增强氧化锆的韧性, 解决其存在的低温老化问题。随着齿科氧化锆陶瓷抗老化性能的提高以及健康功能化的未来需求, 其在齿科修复领域的应用将会越来越广泛。

We evaluate the ablation thresholds of Er:YAG and Er,Cr:YSGG laser for enamel and dentin. A total of 140 dental slices is evenly divided into two groups: the dentin group and the enamel group. Dental tissues are irradiated with either an Er:YAG laser or an Er,Cr:YSGG laser with pulse widths in the order of 100 \mu s. The laser fluence is increased gradually until the ablation crater is formed. The laser ablation threshold is calculated using probit analysis. The ablation thresholds of the Er:YAG laser for dentin and enamel range from 2.88 to 3.36 J/cm2 and from 2.94 to 3.8 J/cm2, respectively, and the ablation thresholds of the Er,Cr:YSGG laser for dentin and enamel range from 2.92 to 4.2 J/cm2 and from 4.93 to 5.66 J/cm2, respectively.

回顾了“激光钻”的发展历程，归纳总结了牙硬组织的光学性质及牙硬组织与激光的相互作用方式和机制，综述了激光在牙釉质、牙本质、牙结石和牙槽骨等硬组织上的应用研究动态和最新进展，并对其存在的问题及发展趋势进行了探讨。分析表明：硬组织激光消融技术在牙科存在广阔的应用前景。

A Chinese skin colour database is established based on measurements taken from nine bodies areas of 202 Chinese individuals to move towards accurate skin colour reproduction. The colour appearance of each skin point is predicted, and a comprehensive colour gamut for Chinese skin is determined. A consistent colour shift between facial and arm colours is identified, in which facial colour tends to be more reddish, more colourful, and darker than arm colour. Moreover, Chinese females are found to have lighter, paler, and more yellowish skin than Chinese males. Variations in Chinese skin colour are quantified, and body area differences and gender differences are shown to have significant effects on Chinese skin colour.