Anusavice K J
College of Dentistry, University of Florida, Gainesville 32610.
Adv Dent Res. 1992 Sep;6:82-9. doi: 10.1177/08959374920060012201.
The degradation of dental ceramics generally occurs because of mechanical forces or chemical attack. The possible physiological side-effects of ceramics are their tendency to abrade opposing dental structures, the emission of radiation from radioactive components, the roughening of their surfaces by chemical attack with a corresponding increase in plaque retention, and the release of potentially unsafe concentrations of elements as a result of abrasion and dissolution. The chemical durability of dental ceramics is excellent. With the exception of the excessive exposure to acidulated fluoride, ammonium bifluoride, or hydrofluoric acid, there is little risk of surface degradation of virtually all current dental ceramics. Extensive exposure to acidulated fluoride is a possible problem for individuals with head and/or neck cancer who have received large doses of radiation. Such fluoride treatment is necessary to minimize tooth demineralization when saliva flow rates have been reduced because of radiation exposure to salivary glands. Porcelain surface stains are also lost occasionally when abraded by prophylaxis pastes and/or acidulated fluoride. In each case, the solutes are usually not ingested. Further research that uses standardized testing procedures is needed on the chemical durability of dental ceramics. Accelerated durability tests are desirable to minimize the time required for such measurements. The influence of chemical durability on surface roughness and the subsequent effect of roughness on wear of the ceramic restorations as well as of opposing structures should also be explored on a standardized basis.
牙科陶瓷的降解通常是由机械力或化学侵蚀引起的。陶瓷可能产生的生理副作用包括磨损对颌牙齿结构的倾向、放射性成分的辐射释放、化学侵蚀导致其表面粗糙并相应增加菌斑滞留，以及磨损和溶解导致潜在不安全浓度的元素释放。牙科陶瓷的化学耐久性极佳。除了过度暴露于酸化氟化物、氟化氢铵或氢氟酸外，几乎所有当前牙科陶瓷的表面降解风险都很小。对于接受过大剂量辐射的头颈癌患者，过度暴露于酸化氟化物可能是个问题。由于唾液腺受到辐射，唾液流速降低时，这种氟化物治疗对于尽量减少牙齿脱矿是必要的。当被预防性糊剂和/或酸化氟化物磨损时，瓷表面污渍偶尔也会消失。在每种情况下，溶质通常不会被摄入。需要采用标准化测试程序对牙科陶瓷的化学耐久性进行进一步研究。理想的是进行加速耐久性测试，以尽量减少此类测量所需的时间。还应在标准化基础上探讨化学耐久性对表面粗糙度的影响以及粗糙度对陶瓷修复体及其对颌结构磨损的后续影响。
