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Effects of ultramorphological changes on adhesion to lased dentin—Scanning electron microscopy and transmission electron microscopy analysis
Author(s) -
Moretto Simone G.,
Azambuja Nilton,
AranaChavez Victor E.,
Reis Andre F.,
Giannini Marcelo,
Eduardo Carlos de P.,
De Freitas Patricia M.
Publication year - 2011
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.20949
Subject(s) - dentin , scanning electron microscope , adhesive , materials science , transmission electron microscopy , irradiation , laser , erbium , bond strength , composite material , microscopy , layer (electronics) , optics , nanotechnology , optoelectronics , doping , physics , nuclear physics
Dentin irradiation with erbium lasers has been reported to alter the composite resin bond to this treated surface. There is still a lack of studies reporting the effect of erbium lasers on dentin organic content and elucidating how laser treatment could interfere in the quality of the resin–dentin interface. This study aimed to evaluate the effect of erbium laser irradiation on dentin morphology and microtensile bond strength (μTBS) of an adhesive to dentin. Seventy‐two dentin disks were divided into nine groups ( n = 8): G1‐Control (600‐grit SiC paper); Er:YAG groups: G2‐ 250 mJ/4 Hz; G3‐ 200 mJ/4 Hz; G4‐ 180 mJ/10 Hz; G5‐ 160 mJ/10 Hz; Er,Cr:YSGG groups: G6‐ 2 W/20 Hz; G7‐ 2.5 W/20 Hz; G8‐ 3 W/20 Hz; G9‐ 4 W/20 Hz. Specimens were processed for cross‐sectional analysis by scanning electron microscopy (SEM) ( n = 3), transmission electron microscopy (TEM) ( n = 2), and adhesive interface ( n = 3). Forty‐five dentin samples ( n = 5) were restored and submitted to μTBS testing. ANOVA (α = 5%) revealed that G1 presented the highest μTBS values and irradiated groups did not differ from each other. TEM micrographs showed a superficial layer of denatured collagen fibrils. For SEM micrographs, it was possible to verify the laser effects extending to dentin subsurface presenting a rough aspect. Cross‐sectional dentin micrographs of this hybridized surface revealed a pattern of modified tags with ringlike structures around it. This in vitro study showed that erbium laser irradiation interacts with the dental hard tissue resulting in a specific morphological pattern of dentin and collagen fibrils that negatively affected the bond strength to composite resin. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.