title: Effect of bleaching on microhardness of esthetic restorative materials.
abstract: This study evaluated the effect of a high-concentration carbamide peroxide–containing home bleaching system (Opalescence PF) and a hydrogen peroxide–containing over-the-counter bleaching system (Treswhite Supreme) on the microhardness of two nanocomposites (Filtek Supreme XT and Premise) and leucite-reinforced glass ceramic (Empress Esthetic), glass ceramic (Empress 2 layering), and feldspathic porcelain (Matchmaker MC). A total of 100 specimens, 20 of each kind of the restorative materials, 2 mm in thickness and 10 mm in diameter, were fabricated. Then the specimens were polished with SiC paper and 1 μm alumina polishing paste. After polishing, porcelain specimens were glazed in accordance with the manufacturer's instructions. Each type of restorative material was then randomly divided into two groups (n=10), and the specimens were treated with either Opalescence PF or Treswhite Supreme. The microhardness of the specimens before bleaching (baseline) and after bleaching was determined using a digital microhardness tester. Data were analyzed using the Mann-Whitney U-test and the Wilcoxon test. Opalescence PF significantly influenced the hardness of all the restorative materials. Statistically significant decreases with respect to before bleaching were found for Premise (p=0.005), Empress Esthetic (p=0.003), Empress 2 layering (p=0.005), and Matchmaker-MC (p=0.003), whereas a statistically significant increase was observed in Filtek Supreme XT (p=0.028). The difference in the microhardness values between before and after bleaching using Treswhite Supreme was statistically significant only for Premise (p=0.022). High-concentration carbamide peroxide–containing home bleaching may affect the microhardness of restorative materials.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Yeditepe University, İstanbul, Turkey. ozlemmalkondu@gmail.com
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Malkondu
authors.forename: Haktan
authors.initials: H
authors.lastname: Yurdagüven
authors.forename: Esra Can
authors.initials: EC
authors.lastname: Say
authors.forename: Ender
authors.initials: E
authors.lastname: Kazazoğlu
authors.forename: Mübin
authors.initials: M
authors.lastname: Soyman
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D000077463:Carbamide Peroxide; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing; D003776:Dental Porcelain / Q000737:chemistry*; D004338:Drug Combinations; D006244:Hardness; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry; D010545:Peroxides / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D058205:Tooth Bleaching Agents / Q000737:chemistry*; D014508:Urea / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D003764:Dental Materials; D004338:Drug Combinations; C118557:Empress 2; C474035:Filtek Supreme; C075815:IPS-Empress ceramic; D018020:Lithium Compounds; D010545:Peroxides; D011145:Polyvinyls; D017680:Potassium Compounds; D017655:Silicon Compounds; D058205:Tooth Bleaching Agents; C507210:premise composite resin; C093177:tooth-bleaching agent, Opalescence; D003776:Dental Porcelain; C016447:feldspar; C078519:leucite; D000077463:Carbamide Peroxide; C023506:Glass ceramics; D014508:Urea; D006861:Hydrogen Peroxide; D000537:Aluminum Oxide; C022088:silicon carbide