de Paula A B, de Fúcio S B P, Alonso R C B, Ambrosano G M B, Puppin-Rontani R M
Oper Dent. 2014 May-Jun;39(3):E109-17. doi: 10.2341/12-340. Epub 2013 Dec 2.
The aim of this in vitro study was to investigate the effect of chemical degradation on the surface roughness (Ra) and hardness (Knoop hardness number [KHN]) of nano restorative materials.
Disc-shaped specimens (5-mm diameter; 2-mm thick) of Filtek Z350 and TPH Spectrum composites and the Vitremer and Ketac Nano light-curing glass ionomer cements were prepared according to the manufacturers' instructions. After 24 hours, polishing procedures were performed and initial measurements of Ra and KHN were taken. The specimens were divided into 12 groups (n=10) according to material and storage media: artificial saliva, orange juice, and Coca-Cola. After 30 days of storage, the specimens were reevaluated for Ra and KHN. The pH values of the storage media were measured weekly. Data were tested for significant differences by repeated-measures three-way analysis of variance and Tukey tests (p<0.05).
Composites were found to present lower roughness values and higher hardness values than the ionomeric materials under all storage conditions. After degradation, the KHN of all experimental samples decreased significantly, while the Ra of the ionomeric materials increased, depending on the media, with a markedly negative impact of Coca-Cola and orange juice. There was no difference among the storage media for Filtek Z350 with regard to the KHN values. Nanofillers did not show any influence on the roughness and hardness of resin-modified glass ionomer cements and resin composites concerning their degradation resistance.
本体外研究旨在探讨化学降解对纳米修复材料表面粗糙度（Ra）和硬度（努氏硬度值[KHN]）的影响。
按照制造商的说明制备Filtek Z350和TPH Spectrum复合材料以及Vitremer和Ketac Nano光固化玻璃离子水门汀的圆盘形试样（直径5毫米；厚2毫米）。24小时后，进行抛光处理并测量Ra和KHN的初始值。根据材料和储存介质将试样分为12组（n = 10）：人工唾液、橙汁和可口可乐。储存30天后，重新评估试样的Ra和KHN。每周测量储存介质的pH值。通过重复测量三因素方差分析和Tukey检验（p<0.05）对数据进行显著性差异检验。
发现在所有储存条件下，复合材料的粗糙度值低于离子材料，硬度值高于离子材料。降解后，所有实验样品的KHN显著降低，而离子材料的Ra根据介质不同而增加，其中可口可乐和橙汁的影响明显为负。Filtek Z350在KHN值方面，储存介质之间没有差异。纳米填料对树脂改性玻璃离子水门汀和树脂复合材料的粗糙度和硬度及其耐降解性没有任何影响。
