Micromorphology of resin-dentin interfaces using one-bottle etch&rinse and self-etching adhesive systems on laser-treated dentin surfaces: a confocal laser scanning microscope analysis.
OBJECTIVE
This study evaluated the hybrid layer (HL) morphology created by three adhesive systems (AS) on dentin surfaces treated with Er:YAG laser using two irradiation parameters.


METHODS
Occlusal flat dentin surfaces of 36 human third molars were assigned into nine groups (n = 4) according to the following ASs: one bottle etch&rinse Single Bond Plus (3M ESPE), two-step Clearfil Protect Bond (Kuraray), and all-in-one S(3) Bond (Kuraray) self-etching, which were labeled with rhodamine B or fluorescein isothiocyanate-dextran and were applied to dentin surfaces that were irradiated with Er:YAG laser at either 120 (38.7 J/cm(2)) or 200 mJ/pulse (64.5 J/cm(2)), or were applied to untreated dentin surfaces (control group). The ASs were light-activated following MI and the bonded surfaces were restored with resin composite Z250 (3M ESPE). After 24 hours of storage in vegetable oil, the restored teeth were vertically, serially sectioned into 1-mm thick slabs, which had the adhesive interfaces analyzed with confocal laser microscope (CLSM-LSM 510 Meta). CLSM images were recorded in the fluorescent mode from three different regions along each bonded interface.


RESULTS
Non-uniform HL was created on laser-irradiated dentin surfaces regardless of laser irradiation protocol for all AS, while regular and uniform HL was observed in the control groups. "Stretch mark"-like red lines were found within the HL as a result of resin infiltration into dentin microfissures, which were predominantly observed in 200 mJ/pulse groups regardless of AS. Poor resin infiltration into peritubular dentin was observed in most regions of adhesive interfaces created by all ASs on laser-irradiated dentin, resulting in thin resin tags with neither funnel-shaped morphology nor lateral resin projections.


CONCLUSIONS
Laser irradiation of dentin surfaces at 120 or 200 mJ/pulse resulted in morphological changes in HL and resin tags for all ASs evaluated in the study.
de Oliveira
Marcelo Tavares
MT
Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP 13414-903, Brazil.
Arrais
Cesar Augusto Galvão
CA
Aranha
Ana Cecília
AC
de Paula Eduardo
Carlos
C
Miyake
Katsuya
K
Rueggeberg
Frederick Allen
FA
Giannini
Marcelo
M
D055117:Curing Lights, Dental; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000145:classification; D045662:Dental Etching / Q000379:methods*; D003804:Dentin / Q000166:cytology*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D007834:Lasers; D053844:Lasers, Solid-State; D018613:Microscopy, Confocal; D008964:Molar, Third; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties / Q000528:radiation effects; D013718:Tensile Strength / Q000528:radiation effects
D003738:Dental Cements; D017220:Dentin-Bonding Agents; D019279:Resin Cements