title: Strontium effects on root dentin tubule occlusion and nanomechanical properties.
abstract: OBJECTIVE
  Dentin hypersensitivity often is treated by promotion of dentin tubule occlusion. In this in vitro study we evaluated nanomechanical properties and degree of tubule occlusion conferred to sound and demineralized human root dentin following treatment with a 10% (w/w) strontium acetate solution and its relation to the treatment duration and delivery method.
  
  
  METHODS
  24 human cervical root dentin disks (8 groups of 3) were polished through 0.25 μm. 12 disks were subjected to an acid challenge (1% citric acid, pH 3.8) for 2 min. The specimens were incubated in artificial saliva, treated by soaking or brushing with deionized (DI) water or a solution of 10% strontium acetate for 2 min twice a day for 28 days. The occlusion percent and nanomechanical properties were determined at the baseline, 5, 14 and 28 days. Cross-sectioned specimens were prepared to evaluate the depth affected by strontium acetate / dentin interaction by SEM. Statistical analysis was performed using linear mixed effects models.
  
  
  RESULTS
  A 10% strontium acetate treatment over 5-28 days significantly increased tubule occlusion for normal root dentin and to a lesser extent for demineralized dentin and increased the AFM based nanomechanical properties of demineralized dentin. Brushing was more effective than soaking in recovery of properties of demineralized dentin when treated with strontium. No difference in tubuleocclusion was found between the two delivery methods.
  
  
  CONCLUSIONS
  Strontium acetate itself proved to have the ability to occlude dentin tubules and result in small changes in the mechanical properties of dentin.
authors.affiliation: Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, 707 Parnassus Avenue, San Francisco, CA 94143-0758, USA. Electronic address: kuniko.saeki@ucsf.edu.
authors.forename: Kuniko
authors.initials: K
authors.lastname: Saeki
authors.affiliation: Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, 707 Parnassus Avenue, San Francisco, CA 94143-0758, USA.
authors.forename: Grayson W
authors.initials: GW
authors.lastname: Marshall
authors.affiliation: Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, 707 Parnassus Avenue, San Francisco, CA 94143-0758, USA.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Gansky
authors.affiliation: GlaxoSmithKline, Oral Care Medical Affairs, Research & Development, St Georges Avenue, Weybridge, Surrey KT13 0DE, United Kingdom.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Parkinson
authors.affiliation: Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, 707 Parnassus Avenue, San Francisco, CA 94143-0758, USA.
authors.forename: Sally J
authors.initials: SJ
authors.lastname: Marshall
mesh_terms: D000085:Acetates / Q000737:chemistry*; D003804:Dentin / Q000187:drug effects*; D057133:Dentin Desensitizing Agents / Q000737:chemistry*; D003807:Dentin Sensitivity / Q000188:drug therapy; D006801:Humans; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D012464:Saliva, Artificial; D013324:Strontium / Q000737:chemistry*; D013499:Surface Properties; D014092:Tooth Root / Q000187:drug effects*; D014099:Toothbrushing
chemical_list: D000085:Acetates; D057133:Dentin Desensitizing Agents; D012464:Saliva, Artificial; C106741:strontium acetate; D013324:Strontium
keywords: AFM; Dental erosion; Dentin hypersensitivity; Nanomechanical properties; Occlusion; Root caries; Strontium acetate