Regular bioactive resin composites associated with low-shrinkage and bulk-fill characteristics: comparative structural characterization and physical-mechanical properties under the erosive challenge

• Ano de defesa: 2024
• Autor(a) principal: Jacomine, Juliana Carvalho
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Composite resins; Elastic modulus; Erosão dentária; Flexural strength; Mechanical tests; Módulo de elasticidade; Resinas compostas; Resistência à flexão; Testes mecânicos; Tooth erosion
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/25/25148/tde-22012025-120957/

Bioactive composite resins can be a favorable option for the rehabilitation of prevalent cases of erosive tooth wear, but their physico-mechanical properties must perform satisfactorily in the face of constant erosive challenges. Recent low-shrinkage and bulk-fill resins possess characteristics that reduce the effects inherent to polymerization shrinkage, a common obstacle among resin materials. The aim of this study was to structurally characterize and compare the physico-mechanical properties of high-viscosity bioactive composite resins, with and without low-shrinkage or bulk-fill characteristics, when subjected to an erosive challenge. Six categories of materials were evaluated: resin-modified glass ionomer cement (GC Gold Label LC 2 GL), high-viscosity non-bioactive composite resins conventional (Filtek Z350 XT Z) and bulk-fill (Filtek One Bulk Fill ONE), and bioactive composite resins conventional (Beautifil II BII), bulk-fill (Beautifil Bulk Restorative BB), and low-shrinkage (Beautifil II LS LS). For this, specimens were fabricated and evaluated under control conditions (artificial saliva or dry) and eroded (orange juice/ 3 cycles/ 5 minutes/ 5 days), and evaluated in three-point flexural strength - FS and modulus of elasticity - ME (n=10), color stability - CS and surface microhardness - SM (n=8), and energy-dispersive X-ray spectroscopy and scanning electron microscopy - EDS/SEM (n=2). Additionally, polymerization shrinkage stress - SS and degree of conversion - DC (n=6) of the materials were assessed under control conditions. All composite resins exhibited FS values greater than 80 MPa, and the erosive challenge did not impact the direct comparison between them, although differences emerged among the eroded groups. GL and LS exhibited the lowest ME values. Only GL did not exhibit CS after immersion in orange juice. The erosive challenge impacted the MS of all tested resins, and those with S-PRG had their MS reduced even under control conditions in artificial saliva. EDS/SEM analysis confirmed that GL underwent the greatest visual alteration after acid exposure, with considerable loss of fluoride ions from the surface. In terms of SS, no composite resin showed statistically significant differences. Z, ONE, and LS exhibited the 12 highest DC values. The set of analyses indicates that, despite the differences observed in some properties, all resins exhibit characteristics superior to acceptable indices. However, it is noteworthy that among the bioactive materials, the LS composite resin presented more consistent results and apparent stability against the acid challenge, which could be a pertinent option for the rehabilitation of erosive tooth wear cases.