Luciano Rosa de Lacerda1, Mayara Bossardi2, Werônica Jaernevay Silveira Mitterhofer1, Fabíola Galbiatti de Carvalho3, Hugo Lemes Carlo3, Evandro Piva4, Eliseu Aldrighi Münchow5. 1. Department of Dentistry, Health Science Institute, Federal University of Juiz de Fora, Governador Valadares, Brazil. 2. BioMat Group, Materials Applied to Biosystems, Federal University of Juiz de Fora, Governador Valadares, Brazil. 3. Department of Dentistry, Health Science Institute, Federal University of Juiz de Fora, Governador Valadares, Brazil; BioMat Group, Materials Applied to Biosystems, Federal University of Juiz de Fora, Governador Valadares, Brazil; Graduate Program in Dental Clinic, Federal University of Juiz de Fora, Juiz de Fora, Brazil. 4. Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, Brazil. 5. Department of Dentistry, Health Science Institute, Federal University of Juiz de Fora, Governador Valadares, Brazil; BioMat Group, Materials Applied to Biosystems, Federal University of Juiz de Fora, Governador Valadares, Brazil; Graduate Program in Dental Clinic, Federal University of Juiz de Fora, Juiz de Fora, Brazil. Electronic address: eliseumunchow@gmail.com.
Abstract
PURPOSE: To investigate the mechanical performance and fracture reliability of new generation, bulk-fill resin composites of different viscosities. METHODS: Forty sound maxillary premolars were prepared into Class I cavities comprised of 5 mm width × 5 mm length × 5 mm thickness. The teeth were randomly allocated into four groups (n = 10) according to the restorative material: Negative control - without restoration; Positive control - conventional resin composite (Opallis; FGM) was applied using increments of up to 2.0 mm-thick; Bulk-Regular - bulk-fill resin composite of regular viscosity (Opus Bulk Fill; FGM) was applied using a single increment of 5 mm-thick; and Bulk-Flow - a low-viscosity bulk-fill resin composite (Opus Bulk Fill Flow; FGM) was applied as the first increment with ∼3.5 mm-thick, followed by two final increments of Opallis (∼1.5 mm-thick). The teeth were stored at 37 °C, for 24 h, and submitted to a mechanical testing machine (DL500; EMIC) under a compressive loading. Work of fracture (Wf) was also obtained. All data were analyzed using ANOVA and Tukey (α = 5%). Reliability of restorations and probability of failure were analyzed by Weibull analysis. RESULTS: The non-restored teeth showed the weakest behavior of the study. All the restored groups demonstrated similar mechanical properties to each other (p ≥ 0.242). The positive and negative controls failed exclusively within the cohesiveness of enamel/dentin, whereas the bulk-fill-based restorations showed a mixture of cohesive and mixed failures. The restored groups showed an overall similar reliability, although the Bulk-Regular group demonstrated greater characteristic strength than the positive control. CONCLUSION: The novel bulk-fill resin composites of low and regular viscosities show promising application in the restoration of Class I cavities in premolars, demonstrating similar mechanical performance and reliability as compared with restorations prepared using conventional resin composites. From the bulk-fill materials, the version with regular viscosity presented the greatest compliant behavior of the study.
PURPOSE: To investigate the mechanical performance and fracture reliability of new generation, bulk-fill resin composites of different viscosities. METHODS: Forty sound maxillary premolars were prepared into Class I cavities comprised of 5 mm width × 5 mm length × 5 mm thickness. The teeth were randomly allocated into four groups (n = 10) according to the restorative material: Negative control - without restoration; Positive control - conventional resin composite (Opallis; FGM) was applied using increments of up to 2.0 mm-thick; Bulk-Regular - bulk-fill resin composite of regular viscosity (Opus Bulk Fill; FGM) was applied using a single increment of 5 mm-thick; and Bulk-Flow - a low-viscosity bulk-fill resin composite (Opus Bulk Fill Flow; FGM) was applied as the first increment with ∼3.5 mm-thick, followed by two final increments of Opallis (∼1.5 mm-thick). The teeth were stored at 37 °C, for 24 h, and submitted to a mechanical testing machine (DL500; EMIC) under a compressive loading. Work of fracture (Wf) was also obtained. All data were analyzed using ANOVA and Tukey (α = 5%). Reliability of restorations and probability of failure were analyzed by Weibull analysis. RESULTS: The non-restored teeth showed the weakest behavior of the study. All the restored groups demonstrated similar mechanical properties to each other (p ≥ 0.242). The positive and negative controls failed exclusively within the cohesiveness of enamel/dentin, whereas the bulk-fill-based restorations showed a mixture of cohesive and mixed failures. The restored groups showed an overall similar reliability, although the Bulk-Regular group demonstrated greater characteristic strength than the positive control. CONCLUSION: The novel bulk-fill resin composites of low and regular viscosities show promising application in the restoration of Class I cavities in premolars, demonstrating similar mechanical performance and reliability as compared with restorations prepared using conventional resin composites. From the bulk-fill materials, the version with regular viscosity presented the greatest compliant behavior of the study.
Authors: Eliseu A Münchow; Adriana F da Silva; Evandro Piva; Carlos E Cuevas-Suárez; Maria T P de Albuquerque; Rodolfo Pinal; Richard L Gregory; Lorenzo Breschi; Marco C Bottino Journal: J Mater Chem B Date: 2020-11-10 Impact factor: 6.331