Er:YAG-laser and sodium hypochlorite influence on bond to dentin.
OBJECTIVE
The aim of this in vitro study was to verify the interference of previous application of sodium hypochlorite in the bond strength to dentin irradiated with Er:YAG laser (80 mJ, 2 Hz, 25 J/cm(2)), using two adhesive systems with different solvents (Adper Single Bond2 - 3M ESPE [SB] and Prime&Bond 2.1 - Dentsply [PB].


METHODS
Ninety standardized dentin disks were treatment with phosphoric acid etching (PA), PA and 10% sodium hypochlorite (SH), Er:YAG laser (ER), ER and 10% SH. After surface preparation, samples received SB or PB followed by composite resin Z250 (3M ESPE)(n = 10). Tensile bond strength test was performed (0.5 mm/min) 24 h after bonding procedure and one treated dentin disk of each group was selected to scanning and transmission electron microscopy (SEM and TEM) observations. Bond strength test data were evaluated by three-way ANOVA and Tukey (P < 0.05) tests.


RESULTS
Tested systems had similar bonding behavior when applied with conventional method. SH produced no improvement in bond strength. Phosphoric acid etching either associated with SH, or not, provided higher bond strength values than ER. SEM showed typical ablation pattern on dentin after ER irradiation. SH application after PA promoted greater porosity in intertubular dentin exposing secondary tubules. SH used after ER irradiation showed more evident peritubular dentin. TEM results showed that both PA and ER exposed inter- and peri-tubular dentin collagen fibers.


CONCLUSIONS
Er:YAG irradiation had a negative influence on SB adhesive, and in both methods, association of SH did not completely remove collagen fiber network, but altered its configuration.
Graduate Program in Dentistry Restorative Dentistry, Paulista University, São Paulo, Brazil. cintiasaraceni@uol.com.br
Cintia Helena
CH
Saraceni
Edson
E
Liberti
Ricardo Scarparo
RS
Navarro
Alessandra
A
Cassoni
Ricardo
R
Kodama
Margareth
M
Oda
D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000737:chemistry / Q000187:drug effects* / Q000528:radiation effects* / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000494:pharmacology*; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D013718:Tensile Strength / Q000187:drug effects / Q000528:radiation effects
D017220:Dentin-Bonding Agents; D012973:Sodium Hypochlorite