title: Hardness and degree of conversion of posterior packable composites.
abstract: Knoop microhardness and the degree of conversion of three packable composites (SureFil, Alert and Solitaire), a microfil composite (Heliomolar), a microhybrid composite (Herculite) and an indirect laboratory-processed composite (Belleglass) were evaluated as a function of distance from the irradiated surface. Cylindrical specimens (5.0 mm [diameter] x 6.0 mm [length]) of each material were visible light cured for 60 seconds in black-backed Teflon molds and sectioned. Knoop microhardness values were then obtained at 0-, 2- and 4-mm using a 50-gram load and 20 second dwell time. Degree of conversion was determined using Fourier Transform Infrared Spectroscopy. ANOVA (p<0.001) and Tukey Multiple Comparison Test (p<0.05) showed the indirect laboratory-processed composite Belleglass exhibited the highest mean values for both hardness and degree of conversion. Alert exhibited significantly greater hardness than SureFil and Solitaire at 0-mm depth. SureFil had significantly greater hardness than Alert at 4-mm depth. The degree of conversion of SureFil packable composite at 4-mm depth was significantly higher than any of the other direct composites tested.
authors.affiliation: Section of Restorative Dentistry and Prosthodontics, College of Dentistry, The Ohio State University, Columbus, OH, USA. knobloch.3@osu.edu
authors.forename: Lisa  A
authors.initials: L
authors.lastname: Knobloch
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Kerby
authors.forename: Nancy
authors.initials: N
authors.lastname: Clelland
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Lee
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry / Q000528:radiation effects; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D006244:Hardness; D006801:Humans; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D011140:Polyurethanes / Q000737:chemistry / Q000528:radiation effects; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; C406265:Alert composite resin; C029012:Composite Dental Resin; D003188:Composite Resins; C513708:Heliomolar; D008689:Methacrylates; D011108:Polymers; D011140:Polyurethanes; C113049:Solitaire composite resin; C403464:SureFil packable composite; C110370:belleGlass