title: Influence of different pulse durations of Er:YAG laser based on variable square pulse technology on microtensile bond strength of a self-etch adhesive to dentin.
abstract: OBJECTIVE
  The aim of the study was to evaluate the microtensile bond strength of a composite resin to dentin modified with three different pulse durations of the Er:YAG laser based on variable square pulse technology and with one self-etch adhesive.
  
  
  METHODS
  The entire occlusal enamel was removed to obtain flat dentin surface for 48 human molar teeth. The teeth were randomly divided into four experimental groups (n=12 per group), according to the pretreatment of dentin: (1) control group; (2) super short pulse (SSP) (50 μsec); (3) medium short pulse (MSP) (100 μsec); and (4) short pulse (SP) (300 μsec) with Er:YAG laser. The energy of the laser used was 80 mJ with average power of 0.8 W. The microtensile bond strength was tested with a universal testing machine. Two specimens from each experimental group were subjected to scanning electron microscopic (SEM) examination, to observe the irradiated surface.
  
  
  RESULTS
  Dentin surface treated with SSP showed significantly lower microtensile bond strength values (24±9.8 MPa) in comparison with the control group and SP group (35.3±12.8 and 32.9±10.7 MPa, respectively), (p<0.05). The MSP and SP groups did not show any statistically significant difference in microtensile bond strength in comparsion with the control group (p>0.05).
  
  
  CONCLUSIONS
  The use of SP and MSP of the Er:YAG laser with one step self-etch adhesive does not impair or improve the microtensile bond strength in dentin, whereas SSP may not be suitable for dentin surface treatment prior to bonding procedures.
authors: Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia. baraba@sfzg.hr
authors: Anja
authors: A
authors: Baraba
authors: Walter
authors: W
authors: Dukić
authors: Nicoletta
authors: N
authors: Chieffi
authors: Marco
authors: M
authors: Ferrari
authors: Ivica
authors: I
authors: Anić
authors: Ivana
authors: I
authors: Miletić
mesh_terms: D001840:Dental Bonding; D003743:Dental Enamel / Q000528:radiation effects / Q000648:ultrastructure; D045662:Dental Etching / Q000379:methods; D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000528:radiation effects*; D011897:Random Allocation; D013718:Tensile Strength