Refractive index mismatch and monomer reactivity influence composite curing depth.
Limited cure depth is a drawback of light-activated composites. We hypothesize that curing light transmission and cure depth are influenced by monomer reactivity and filler/resin refractive index mismatch. Light transmission throughout cure was recorded for composites based on strontium (refractive index 1.51) or barium (refractive index 1.53) glass fillers. Fillers were mixed (70 wt%) with 4 bisphenol-A diglycidyl-ether-dimethacrylate (bis-GMA):triethylene glycol dimethacrylate (TEGDMA) formulations with refractive indices ranging from 1.4703 to 1.5370. Following polymerization, cure depth and pre- and post-cure translucency parameters were determined. Transmission changes and cure depths related to monomer reactivity and filler/resin refractive index mismatch with significant interaction. Composites became more opaque or translucent on curing. Optimizing filler/resin refractive index mismatch provides increased curing depth and assists shade-matching.
Shortall
A C
AC
The University of Birmingham, School of Dentistry, St. Chad's Queensway, Birmingham B4 6NN, England. a.c.c.shortall@bham.ac.uk
Palin
W M
WM
Burtscher
P
P
D001464:Barium / Q000737:chemistry / Q000528:radiation effects; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D003116:Color; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D005898:Glass / Q000737:chemistry* / Q000528:radiation effects; D006801:Humans; D008422:Materials Testing; D055095:Optics and Photonics; D011092:Polyethylene Glycols / Q000737:chemistry / Q000528:radiation effects; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D011109:Polymethacrylic Acids / Q000737:chemistry / Q000528:radiation effects; D012031:Refractometry; D013324:Strontium / Q000737:chemistry / Q000528:radiation effects; D013499:Surface Properties; D013696:Temperature
D003188:Composite Resins; D011108:Polymers; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; D001464:Barium; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D013324:Strontium