Jing Fu, Abdulaziz Alayed, Qi Xue, Nikolaos Silikas, David C Watts
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引用次数: 0
Abstract
Objectives: To characterize the polymerization shrinkage strain, shrinkage stress, and Martens hardness kinetics of a self-cured bulk-fill resin composite (STELA Automix) under different bonding protocols, and to compare its behavior with two light-cured bulk-fill composites.
Methods: STELA Automix was evaluated either alone (STA) or with its dedicated STELA Primer (STA+PST), Adhese Universal (STA+AU), or Adhese Universal followed by light curing (STA+AU+LCU). Polymerization shrinkage strain (bonded-disk, 60 min, n = 3), shrinkage stress (Bioman II analyzer, 3600 s, n = 3), and Martens hardness (up to 7 days, n = 5) were measured for STELA and two light-cured bulk-fill composites, Filtek One Bulk Fill and SureFil SDR flow (SDR), under equivalent conditions (23 °C). Data were analyzed by one-way ANOVA and Tukey's test (α = 0.05).
Results: All STELA configurations showed higher final shrinkage strain than the light-cured bulk-fill materials (p < 0.05). Final shrinkage stresses ranged from 1.34 to 2.39 MPa, with STA + AU yielding the lowest and STA + AU + LCU the highest values (p < 0.05). The dedicated STELA Primer advanced shrinkage onset and increased the interval between onset and the maximum shrinkage-strain rate (Δt), indicating an altered early shrinkage-kinetic profile in the bonded configuration. Across the STELA protocols, shrinkage-rate development extended over tens of seconds, while Martens hardness increased gradually over 7 days and ultimately exceeded that of SDR.
Significance: Despite higher polymerization shrinkage strain than the light-cured composites, STELA exhibited slower stress build-up and a prolonged viscoelastic response during early polymerization. The dedicated primer altered the early shrinkage-kinetic profile by increasing Δt, whereas additional light activation compressed this interval. This kinetic profile, which can be modified by formulation and bonding protocol, may be as critical as shrinkage magnitude in shaping interfacial stress development in bulk-fill composites.
期刊介绍：
Dental Materials publishes original research, review articles, and short communications.
Academy of Dental Materials members click here to register for free access to Dental Materials online.
The principal aim of Dental Materials is to promote rapid communication of scientific information between academia, industry, and the dental practitioner. Original Manuscripts on clinical and laboratory research of basic and applied character which focus on the properties or performance of dental materials or the reaction of host tissues to materials are given priority publication. Other acceptable topics include application technology in clinical dentistry and dental laboratory technology.
Comprehensive reviews and editorial commentaries on pertinent subjects will be considered.
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