title: Optimizing light-cured composite through variations in camphorquinone and butylhydroxytoluene concentrations.
abstract: The use of a free-radical polymerization inhibitor, butylhydroxytoluene (BHT), and a common photo-initiator, camphorquinone (CQ), to reduce polymerization stress in dental composite was investigated in this study. Samples were prepared by mixing Bis-GMA, UDMA, and TEGDMA at a 1:1:1 ratio (wt%), and silanized borosilicate glass fillers at 70 wt% were added to form the composite. Sixteen groups of resin composite were prepared using combinations of four CQ (0.1%, 0.5%, 1.0%, and 1.5%) and four BHT (0.0%, 0.5%, 1.0%, and 1.5%) concentrations. For each group, six properties were tested, including flexural strength (FS), flexural modulus (FM), degree of conversion (DC), contraction stress (CS), stress rate, and gel point (GP). The effects of CQ and BHT combinations on each of these properties were evaluated using two-way analysis of variance (ANOVA) and Fisher's Protected Least Significant Differences test at the 5% significance level. Groups with low CQ and BHT showed moderate values for FS, FM, and CS with a 70% DC. Increasing the BHT concentration caused a decrease in CS and DC with an increase in GP values. Increasing the CQ content led to a steady increase in values for FS and FM. High CQ and BHT combinations showed the most promising values for mechanical properties with low stress values.
authors.affiliation: King Abdulaziz University, School of Dentistry, Department of Operative Dentistry, Jeddah, Saudi Arabia.
authors.forename: Hani
authors.initials: H
authors.lastname: Nassar
authors.affiliation: Indiana University, School of Dentistry, Department of Restorative Dentistry, Indianapolis, IN, USA.
authors.forename: Tien-Min
authors.initials: TM
authors.lastname: Chu
authors.affiliation: Indiana University, School of Dentistry, Department of Restorative Dentistry, Indianapolis, IN, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Platt
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002084:Butylated Hydroxytoluene / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D055119:Elastic Modulus; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D012016:Reference Values; D013314:Stress, Mechanical; D013729:Terpenes / Q000737:chemistry*; D013997:Time Factors
chemical_list: D003188:Composite Resins; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D013729:Terpenes; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D002084:Butylated Hydroxytoluene; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C048339:camphoroquinone