Nanoscopic dynamic mechanical analysis of resin-infiltrated dentine, under in vitro chewing and bruxism events

Manuel Toledano; Estrella Osorio; Inmaculada Cabello; Fátima S Aguilera; Modesto T López-López; Manuel Toledano-Osorio; Raquel Osorio

doi:10.1016/j.jmbbm.2015.09.003

Nanoscopic dynamic mechanical analysis of resin-infiltrated dentine, under in vitro chewing and bruxism events

J Mech Behav Biomed Mater. 2016 Feb:54:33-47. doi: 10.1016/j.jmbbm.2015.09.003. Epub 2015 Sep 12.

Authors

Manuel Toledano¹, Estrella Osorio², Inmaculada Cabello², Fátima S Aguilera², Modesto T López-López³, Manuel Toledano-Osorio², Raquel Osorio²

Affiliations

¹ University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain. Electronic address: toledano@ugr.es.
² University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain.
³ University of Granada, Faculty of Science, Applied Physics Department, Fuente Nueva s/n, 18071 Granada, Spain.

PMID: 26414515
DOI: 10.1016/j.jmbbm.2015.09.003

Abstract

The aim of this study was to evaluate the induced changes in mechanical behavior and bonding capability of resin-infiltrated dentine interfaces, after application of mechanical stimuli. Dentine surfaces were subjected to partial demineralization through 37% phosphoric acid etching followed by the application of an etch-and-rinse dentine adhesive, Single Bond (3M/ESPE). Bonded interfaces were stored in simulated body fluid during 24h, and then tested or submitted to the mechanical loading challenge. Different loading waveforms were applied: No cycling (I), 24h cycled in sine (II) or square (III) waves, sustained loading held for 24h (IV) or sustained loading held for 72h (V). Microtensile bond strength (MTBS) was assessed for the different groups. Debonded dentine surfaces were studied by field emission scanning electron microscopy (FESEM). At the resin-dentine interface, both the hybrid layer (HL) and the bottom of the hybrid layer (BHL), and both peritubular and intertubular were evaluated using a nanoindenter in scanning mode. The load and displacement responses were used to perform the nano-Dynamic Mechanical analysis and to estimate the complex and storage modulus. Dye assisted Confocal Microscopy Evaluation was used to assess sealing ability. Load cycling increased the percentage of adhesive failures in all groups. Specimens load cycled in held 24h attained the highest complex and storage moduli at HL and BHL. The storage modulus was maximum in specimens load cycled in held 24h at peritubular dentine, and the lowest values were attained at intertubular dentine. The storage modulus increased in all mechanical tests, at peritubular dentine. An absence of micropermeability and nanoleakage after loading in sine and square waveforms were encountered. Porosity of the resin-dentine interface was observed when specimens were load cycled in held 72h. Areas of combined sealing and permeability were discovered at the interface of specimens load cycled in held 24h. Crack-bridging images appeared in samples load cycled with sine waveform, after FESEM examination.

Keywords: Adhesives; DMA; Dentine; Load cycling; Sealing.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adhesiveness
Biomechanical Phenomena
Bruxism* / physiopathology
Dentin / chemistry*
Mastication*
Materials Testing*
Mechanical Phenomena*
Nanotechnology*
Resins, Synthetic / chemistry*
Tensile Strength
Weight-Bearing

Substances

Resins, Synthetic