title: Bonding strategies of resin cement to Er,Cr:YSGG lased dentin: micro-CT evaluation and microshear bond strength testing.
abstract: OBJECTIVE
  Pretreatment of the tooth surface is essential for establishing effective micromechanical retention between it and the restoration. The purpose of this study was to evaluate the bond strength between the resin and the Er,Cr:YSGG laser irradiated dentin and to examine morphologic characterization of the dentin-resin interface. In addition, the study evaluated the quantity of opened and closed dentinal tubules.
  
  
  METHODS
  Thirty extracted human molars were sectioned into samples of 1 mm thickness. The samples were randomly assigned to two groups containing 15 specimens each. Surface treatments were not applied to the samples in the control group and the samples in the experimental group were irradiated with an Er,Cr:YSGG laser. Two resin cement samples were polymerized on the surface of each sliced dentin. The microshear bond strength (μSBS) between dentin and cement (n = 30 for each group) was measured with a universal testing machine. The topography and morphology of the resin-dentin interface were evaluated by micro-CT (n = 20 for each group). The areas of closed tubular space, closed porosity, area of open tubular space, open porosity, total area of tubular space and fractal dimension were investigated by micro-CT.
  
  
  METHODS
  The data for each parameter were analyzed by Shapiro-Wilk and Student's t test (p&lt;0.05).
  
  
  RESULTS
  µSBS values for control group were higher than experimental group. Dentin surfaces in the control group revealed less closed and more opened dentin tubules compared to the experimental group. Total area of tubular space was found to have decreased due to the laser ablation. There was no significant difference between the fractal dimensions of the control and experimental groups.
  
  
  CONCLUSIONS
  The lased dentin surface was not favorable for the bonding mechanism due to alterations in the dentinal structure.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Okan University, Istanbul - Turkey.
authors.forename: Gökçe
authors.initials: G
authors.lastname: Meriç
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Near East University, Nicosia - Turkish Republic of Northern Cyprus.
authors.forename: Simge
authors.initials: S
authors.lastname: Taşar
authors.affiliation: Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Ankara University, Ankara - Turkey.
authors.forename: Kaan
authors.initials: K
authors.lastname: Orhan
mesh_terms: D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000502:physiology* / Q000528:radiation effects; D017220:Dentin-Bonding Agents / Q000494:pharmacology*; D006801:Humans; D053844:Lasers, Solid-State; D011897:Random Allocation; D019279:Resin Cements / Q000494:pharmacology*; D033081:Shear Strength; D055114:X-Ray Microtomography
chemical_list: D017220:Dentin-Bonding Agents; D019279:Resin Cements