title: Evaluation of the micro-mechanical strength of resin bonded-dentin interfaces submitted to short-term degradation strategies.
abstract: The aim of this study was to evaluate the microtensile bond strength (μTBS) and confocal micropermeability of resin bonded-dentin specimens created using two representative two-step/self-etch adhesives submitted to short-term period degradation strategies such as simulated pulpal pressure, thermo- or mechanical-cycling challenges. Clearfil SE Bond (CSE) and Silorane adhesive (SIL) were bonded to flat deep dentin from seventy extracted human molars and light-cured for 10 s. Composite build-ups were constructed using with Filtek Z350 XT and Filtek P90 respectively. The specimens of each adhesive group were subjected to three different accelerated aging methods: (1) thermo-cycling challenge (5000 cycles); (2) mechanical-cycling load (200,000 cycles); (3) experiment and (4) conventional method for simulated pulpal pressure (20 cm H₂O). Control resin-bonded specimens were stored in distilled water for 24 h. μTBS and confocal microscopy (CLSM) micropermeability evaluation were performed and the results were analyzed using Two-way ANOVA and Tukey's tests (α=0.05). The CLSM evaluation revealed micro-cracks within the Silorane-bonded dentin subsequent to mechanical-cycling load, whereas, the simulated pulpal pressure induced evident micropermeability in both bonding agents. Mechanical loading provides discernible bonding degradation in a short-term period in resin-bonded dentin created using two-step/self-etch adhesives. However, simulated pulpal pressure may reduce the sealing ability of self-etch adhesives causing greater water uptake within the resin-dentin interface.
authors.affiliation: Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas, Limeira Avenue 901, 13414-903 Piracicaba, Brazil. victorpfeitosa@hotmail.com
authors.forename: Victor P
authors.initials: VP
authors.lastname: Feitosa
authors.forename: Salvatore
authors.initials: S
authors.lastname: Sauro
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Watson
authors.forename: Américo B
authors.initials: AB
authors.lastname: Correr
authors.forename: Raquel
authors.initials: R
authors.lastname: Osorio
authors.forename: Manuel
authors.initials: M
authors.lastname: Toledano
authors.forename: Lourenço
authors.initials: L
authors.lastname: Correr-Sobrinho
authors.forename: Mário Alexandre C
authors.initials: MA
authors.lastname: Sinhoreti
mesh_terms: D000269:Adhesives / Q000737:chemistry; D003782:Dental Pulp; D003804:Dentin / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010539:Permeability; D011312:Pressure; D012117:Resins, Synthetic / Q000737:chemistry*; D062047:Silorane Resins / Q000737:chemistry; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D000269:Adhesives; D012117:Resins, Synthetic; D062047:Silorane Resins