title: Fatigue limits for composite restorations with and without glass ionomer cement liners.
abstract: This laboratory study compared the flexural endurance limits of clinical combinations of dental composite with and without glass ionomer cement (GIC) liners. Using only composite (Filtek Z350), specimens (10 mm long x 2 mm wide x 2 mm thick) in the control group were produced. Two GICs (Vitremer and Vitrebond) were used with the composite to prepare the test groups. Flexural strength and flexural fatigue limit (FFL) tests were performed. The FFL was determined using the staircase method. Data were analyzed by one-way ANOVA and Tukey's test. There was a significant difference in flexural strength values between the composite-only specimens and those produced by composite and GIC (p < 0.05). No statistical difference was observed in the flexural strength values between composite with Vitremer and composite with Vitrebond (p < 0.05). No statistically significant differences were detected in FFL values between composite with Vitremer and composite with Vitrebond; in addition, the mean value of the composite-only specimens differed statistically from those of both composite with Vitremer and composite with Vitrebond (p < 0.05). The FFL was lower than the flexural strength, indicating a decrease in flexural strength of 45 to 50%. Using GICs with composite decreased the mechanical properties (FFL and flexural strength) of the composite.
authors.affiliation: Department of Restorative Dentistry, Dental School of Tres Coracoes, Vale do Rio Verde University, UNINCOR, MG, Brazil.
authors.forename: Claudine Pereira
authors.initials: CP
authors.lastname: Assis
authors.forename: Marcos Ribeiro
authors.initials: MR
authors.lastname: Moyses
authors.forename: Hercilia Marburg
authors.initials: HM
authors.lastname: Teixeira
authors.forename: Jose Carlos Rabelo
authors.initials: JC
authors.lastname: Ribeiro
authors.forename: Joao Gustavo Rabelo
authors.initials: JG
authors.lastname: Ribeiro
authors.forename: Sergio Candido
authors.initials: SC
authors.lastname: Dias
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003736:Dental Cavity Lining; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D018583:Pliability; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D005899:Glass Ionomer Cements; C084550:Vitremer; C067790:Vitrabond