title: Radiotherapy does not impair dentin adhesive properties in head and neck cancer patients.
abstract: OBJECTIVE
  This study evaluated the influence of radiotherapy on the dentin bond strength of teeth extracted from patients who had undergone head and neck radiotherapy.
  
  
  METHODS
  A total of 36 samples were divided into two experimental groups: group I (control group, n = 18) and group II (in vivo irradiated group, n = 18). Groups I and II were further separated into three subgroups (six specimens per subgroup), which were further assigned to the three adhesive system protocols employed: Single Bond 2 (SB) (3M ESPE), Easy Bond (EB) (3M ESPE) and Clearfil SE Bond (CSE) (Kuraray). The adhesive systems were applied to the prepared surface according to the manufacturers' instructions and restored using composite resin (Filtek Supreme, 3M ESPE). After 24 h in deionised water (37(o)C), teeth were horizontally and vertically cut to obtain beam specimens with a cross-section area of 0.8 ± 1.0 mm(2). Specimens were tested in tension using a universal testing machine at a cross-speed of 0.5 mm/min. Fracture patterns were observed under SEM. Data was analysed by two-way analysis of variance (p ≤ 0.05).
  
  
  RESULTS
  No statistically significant difference was found between the irradiated (R/SB = 44.66 ± 10.12 MPa; R/EB = 41.48 ± 12.71 MPa; and R/CSE = 46.01 ± 6.98 MPa) and control group (C/SB = 39.12 ± 9.51 MPa; C/EB = 42.40 ± 6.66 MPa; and C/CSE = 36.58 ± 7.06 MPa) for any of the adhesive systems. All groups presented a predominance of mixed fracture modes.
  
  
  CONCLUSIONS
  Head and neck radiotherapy did not affect dentin bond strength for the adhesive materials tested in this study.
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas-UNICAMP, Limeira Avenue, 901-Piracicaba, São Paulo, Brazil, 13414-903, 52.
authors.forename: Roberta
authors.initials: R
authors.lastname: Galetti
authors.forename: Alan Roger
authors.initials: AR
authors.lastname: Santos-Silva
authors.forename: Alberto Nogueira da Gama
authors.initials: AN
authors.lastname: Antunes
authors.forename: Fabio de Abreu
authors.initials: Fde A
authors.lastname: Alves
authors.forename: Marcio Ajudarte
authors.initials: MA
authors.lastname: Lopes
authors.forename: Mario Fernando
authors.initials: MF
authors.lastname: de Goes
mesh_terms: D000268:Adhesiveness; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements; D013499:Surface Properties; D013718:Tensile Strength; D014081:Tooth Extraction
chemical_list: C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C584661:easy bond; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate