Sharafeddin F, Jamalipour Gr
Associate Professor, Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
J Dent (Tehran). 2010 Winter;7(1):6-12. Epub 2010 Mar 31.
Bleaching agents may not be safe for dental materials. The purpose of this in-vitro study was to evaluate the effects of Opalescent Quick "in-office bleaching gel" containing 35% carbamide peroxide on the surface roughness and hardness of microfilled (Heliomolar) and hybride (Spectrum TPH) composite resins.
Twenty specimens of Spectrum TPH composite resins and twenty Heliomolar composite resins were fabricated using a metallic ring (6.5 mm diameter and 2.5 mm thickness) and light cured, then their surfaces were polished. Specimens of each composite resin were divided into two equal groups. Ten specimens of each type of composite were stored in water at 37°C as the control groups and 35% carbamide peroxide gel (Opalescence Quick) as the other group for 30 minutes a week for 3 weeks. Then the specimens were subject to roughness and hardness tests.
This study revealed that using 35% carbamide peroxide bleaching gels had no significant effect on the surface roughness of Spectrum TPH "hybrid" and Heliomolar "microfilled" composite resins. The surface hardness of Spectrum TPH composite treated with the subject gel significantly increased compared to heliomolar, which had no significant change after treatment with this bleaching gel.
If tooth color matching of the composite had been satisfactory after office bleaching with 35% carbamide peroxide gel, this material would have been acceptable because it has no adverse effect on Heliomolar and Spectrum TPH composite resins.
漂白剂可能对牙科材料不安全。本体外研究的目的是评估含35%过氧化脲的Opalescent Quick“诊室漂白凝胶”对微填料（Heliomolar）和混合型（Spectrum TPH）复合树脂表面粗糙度和硬度的影响。
使用金属环（直径6.5mm，厚度2.5mm）制作20个Spectrum TPH复合树脂标本和20个Heliomolar复合树脂标本，光固化后，对其表面进行抛光。每种复合树脂的标本分为两组。每种类型的复合树脂各10个标本作为对照组，在37°C的水中储存，另一组则使用35%过氧化脲凝胶（Opalescence Quick），每周30分钟，共3周。然后对标本进行粗糙度和硬度测试。
本研究表明，使用35%过氧化脲漂白凝胶对Spectrum TPH“混合型”和Heliomolar“微填料”复合树脂的表面粗糙度没有显著影响。与Heliomolar相比，用该凝胶处理的Spectrum TPH复合树脂的表面硬度显著增加，而用该漂白凝胶处理后，Heliomolar的表面硬度没有显著变化。
如果用35%过氧化脲凝胶进行诊室漂白后复合树脂的牙齿颜色匹配令人满意，那么这种材料是可以接受的，因为它对Heliomolar和Spectrum TPH复合树脂没有不良影响。
