Scanning electron microscopy or optical coherence tomography for the evaluation of the glass fiber reinforced acrylic resin?

Aesthetics and strength are two major criteria for dental materials today. Objective: Easy evaluation of the bond between acrylic resin and glass fbers. Materials and methods: Pre-impregnated woven E-glass fbres (Stick® Net, Stick Tech Ltd Oy) and unidirectional pre-impregnated E-glass fbres (StickTM) were used to reinforce a conventional heat-curing denture base resin (Meliodent, Heraeus Kulzer GmbH&Co.KG) - ISO 1567:1999 (E). The samples were 12 Stick reinforced, 12 Stick net reinforced (Stick tech, Finland) and 12 were un-reinforced (control). Optical coherence tomography (OCT) investigation was performed in the Department of Applied Optics, School of Physical Sciences University of Kent, UK. SEM micrographs of the fractured specimens were taken using a SEM microscope (TESLA BS 343 A) in the Department of Materials Testing - ISIM Timisoara, Romania. The samples were in vacuum gold plated. Results: The SEM images were taken at 48× 55?, 120× 55?, 240× 55?, 480× 55? magnifcations for each sample. The OCT micrographs were taken at 670 nm and 1300 nm. The penetration depth is in micron range up to 2 mm. For each sample investigated at 670 nm, 61 de slices per stuck were taken and for each sample investigated at 1300 nm, minimum 100 slices per stuck were taken. Conclusions: Both methods are useful for the bond in between acrylic resin and glass fbers evaluation. SEM is more laborious than OCT which is able to obtain many precise images in steps up to 1 ?.