title: Mechanical and physical properties of silorane and methacrylate-based composites.
abstract: OBJECTIVE
  This study measured the degree of conversion (DC), sorption, solubility and microhardness of methacrylate (Filtek Z250 and Filtek Z350XT) and silorane-based composites (Filtek P90).
  
  
  METHODS
  DC was measured using near infrared spectroscopy immediately and 24h after the photoactivation. Sorption and solubility measurements were performed after 24h, 4 weeks and 12 weeks of storage in water. Knoop microhardness was measured after 24h and after thermal cycling. The data were statistically analyzed using ANOVA followed by Tukey's, Tamhane or paired t-tests (α=0.05).
  
  
  RESULTS
  The DC for P90 (37.22±1.46) was significantly lower than the Z250 (71.44±1.66) and Z350 (71.76±2.84). Water sorption was highest in the Z250 and lowest in the P90. All the tested composites exhibited similar values after 24h of immersion, and no significant differences were observed. No significant differences were observed between the solubilities of the P90 composite (12 weeks) and the Z250 or Z350 composites (4 weeks). KHN values were less elevated for the P90 composite and similar for the Z250 and Z350 composites. An effect of thermal cycling on KHN values was observed for all the composites (p<0.001).
  
  
  CONCLUSIONS
  Silorane produced the lowest DC and KHN values and exhibited lower water sorption and solubility compared to methacrylate-based composites. These differences suggest that silorane composites exhibit better hydrolytic stability after 3 months of water immersion compared to conventional methacrylate-based composites.
  
  
  CONCLUSIONS
  Silorane had higher hydrolytic stability after 3 months of water immersion than the methacrylate-based resins, despite the lower values of DC and KHN recorded.
authors.affiliation: Department of Restorative Dentistry, Federal University of Alagoas, Campus AC Simões, Av. Lourival Melo Mota, S/N, Tabuleiro do Martins, CEP: 57072-970, Maceió, Alagoas, Brazil. isabelcmporto@gmail.com
authors.forename: Isabel Cristina Celerino de Moraes
authors.initials: IC
authors.lastname: Porto
authors.forename: Flávio Henrique Baggio
authors.initials: FH
authors.lastname: de Aguiar
authors.forename: William Cunha
authors.initials: WC
authors.lastname: Brandt
authors.forename: Priscila Christiane Susy
authors.initials: PC
authors.lastname: Liporoni
mesh_terms: D065966:Absorption, Physicochemical; D000327:Adsorption; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D006244:Hardness; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000737:chemistry*; D055585:Physical Phenomena; D058105:Polymerization; D062047:Silorane Resins / Q000737:chemistry*; D012995:Solubility; D019265:Spectroscopy, Near-Infrared; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D008689:Methacrylates; D062047:Silorane Resins; C544925:filtek P90; C533204:filtek Z350; C555513:silorane composite resin; D014867:Water
keywords: Composites; Degree of conversion; Hardness tests; Solubility; Sorption