title: Nano/micro fluorhydroxyapatite crystal pastes in the treatment of dentin hypersensitivity: an in vitro study.
abstract: OBJECTIVE
  Dentin hypersensitivity (DH) is a prevalent problem. This study aimed to formulate a paste using fluorhydroxyapatite (FA) crystals dispersed in different carriers to treat DH. The ability to occlude patent dentinal tubules and to release ions was investigated.
  
  
  METHODS
  Twenty percent FA/sodium alginate, 40% FA/poly(hydroxyethyl methacylate(HEMA)), and 40% FA/poly(DMA-co-MEA) were applied to etched dentin samples and examined with scanning electron microscopy (SEM) to determine the degree of tubule occlusion. Fluoride electrode was used to measure F release and spectroscopy to evaluate Ca and PO4 release. The cytotoxicity of the synthesized poly(DMA-co-MEA) gel was tested. Kruskall-Wallis test was used to test the differences in ion release between the groups.
  
  
  RESULTS
  FA/poly(DMA-co-MEA) paste obstructed up to 80% of the dentinal tubules, while the coverage was up to 70% for FA/poly(HEMA) and less than 50% for FA/sodium alginate. Fluoride and Ca release was the highest for FA/P(HEMA), 7.2 ± 0.7 and 139.8 ± 32.5 ppm, respectively. The highest concentration of PO4 was 46.2 ± 16.4 ppm for FA/Sodium alginate. No statistical significance was found.
  
  
  CONCLUSIONS
  FA/Poly(DMA-co-MEA) and FA/poly(HEMA) pastes may offer immediate short-term relief of DH because of their ability to occlude the tubules and adhere to wet dentin surfaces. The release of the F, Ca, and PO4 ions may offer long-term relief by forming a mineral barrier both within the dentinal tubules and on the dentin surface.
  
  
  CONCLUSIONS
  The tested materials may offer a long-term treatment for DH.
authors: Department of Conservative Dentistry, The University of Jordan, Amman, Jordan. shr_taha@yahoo.com.|, 1000 Shady Creek Pl, Danville, CA, 94526, USA. shr_taha@yahoo.com.
authors: Sahar T
authors: ST
authors: Taha
authors: Biologic and Materials Sciences Department, University of Michigan, Ann Arbor, MI, USA.
authors: Hua
authors: H
authors: Han
authors: Cariology, Restorative Sciences and Endodontics department (CRSE), University of Michigan, Ann Arbor, MI, USA.
authors: Sywe-Ren
authors: SR
authors: Chang
authors: Biologic and Materials Sciences Department, University of Michigan, Ann Arbor, MI, USA.
authors: Iva
authors: I
authors: Sovadinova
authors: Biologic and Materials Sciences Department, University of Michigan, Ann Arbor, MI, USA.
authors: Kenichi
authors: K
authors: Kuroda
authors: Cavendish Laboratories, University of Cambridge, Cambridge, UK.
authors: Richard M
authors: RM
authors: Langford
authors: Cariology, Restorative Sciences and Endodontics department (CRSE), University of Michigan, Ann Arbor, MI, USA.
authors: Brian H
authors: BH
authors: Clarkson
mesh_terms: D003804:Dentin; D003807:Dentin Sensitivity / Q000188:drug therapy*; D006801:Humans; D006882:Hydroxyapatites / Q000737:chemistry / Q000494:pharmacology*; D053758:Nanoparticles / Q000737:chemistry*; D009824:Ointments
chemical_list: D006882:Hydroxyapatites; D009824:Ointments
keywords: Dentin; Dentin hypersensitivity; Fluorhydroxyapatite; Fluoride release; Nano/micro; Treatment