Influence of shade and light-curing distance on the degree of conversion and flexural strength of a dual-cure core build-up resin composite.
OBJECTIVE
To investigate the influence of shade and light-curing distance on the degree of conversion (DC) and flexural strength (FS) of a dual-cure core build-up resin composite.


METHODS
135 specimens were prepared and divided into three main groups according to the shade of the composite core material; dentin, blue and white shades. Each group was further subdivided into three subgroups according to the light-curing distance; 0 mm, 3 mm and 5 mm. The DC was measured using FTIR spectrometer. For testing the FS, the mini flexural test specimens were prepared and subjected to three point bending test in a universal testing machine. The results were analyzed using two-way and one-way ANOVA followed by Duncan's Multiple Range Test. The significance level was set at P = 0.05.


RESULTS
Both the DC and FS of the dual-cure core build-up material used in this study were influenced by the shade of the material and the light-curing distance. The blue shade exhibited the highest percentage DC values while the white shade revealed the lowest percentage DC. The dentin shade at 0 mm light-curing distance exhibited the highest mean FS value; however the 3 mm and 5 mm light-curing distance of the white shade showed the lowest mean FS values.
Department of Operative Dentistry, Ain-shams University, Nasr City, Cairo, Egypt.
Farid S
FS
El-Askary
Dalia I
DI
El-Korashy
D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D002516:Ceramics / Q000737:chemistry; D003116:Color; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D055117:Curing Lights, Dental; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry / Q000528:radiation effects; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation*; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry / Q000528:radiation effects; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry / Q000528:radiation effects; D011140:Polyurethanes / Q000737:chemistry / Q000528:radiation effects; D011829:Radiation Dosage; D055116:Self-Curing of Dental Resins / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C529053:rebilda DC; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; C023506:Glass ceramics