title: In vitro evaluation of dentinal hydraulic conductance and tubule sealing by a novel calcium-phosphate desensitizer.
abstract: In the current trend of materials used for dentin hypersensitivity treatment, calcium-phosphate-containing desensitizers are expected to have advantages in oral environment. A newly formulated desensitizer containing tetracalcium phosphate and dicalcium phosphate anhydrous (CPD-100) was evaluated in comparison to oxalate containing desensitizer (SS) regarding permeability reduction (PR%) by measuring hydraulic conductance on the etched dentin discs in vitro. CPD-100 exhibited mean PR% of 91%, which significantly increased to 98% after immersion in artificial saliva (AS) for 4 weeks (p < 0.001), while SS showed a significant decrease from 99% to 93% (p < 0.01). SEM observation showed newly formed crystallites on CPD-100 treated dentin, which did not exist in SS treated dentin after AS immersion, suggesting that calcium oxalate inhibited formation of new calcium-phosphate minerals. Five-minute acid challenge did not significantly affect PR% of dentin treated by any of the desensitizers. The energy dispersive X-ray spectroscopy (EDS) analysis indicated that the formed layer of CPD-100 were minerals with similar Ca/P ratio to hydroxyapatite. In conclusion, the newly developed calcium-phosphate desensitizer has the potential to exhibit long-term stability in the oral environment, owing to its chemical properties that promote the crystal growth in salivary fluid.
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan. orn.thanatvarakorn@gmail.com
authors.forename: Ornnicha
authors.initials: O
authors.lastname: Thanatvarakorn
authors.forename: Syozi
authors.initials: S
authors.lastname: Nakashima
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
authors.forename: Taweesak
authors.initials: T
authors.lastname: Prasansuttiporn
authors.forename: Masaomi
authors.initials: M
authors.lastname: Ikeda
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
mesh_terms: D002130:Calcium Phosphates / Q000737:chemistry* / Q000494:pharmacology*; D003460:Crystallization; D003804:Dentin / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D057133:Dentin Desensitizing Agents / Q000737:chemistry* / Q000494:pharmacology*; D003806:Dentin Permeability / Q000187:drug effects / Q000502:physiology; D003807:Dentin Sensitivity / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D057446:Hydrodynamics; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013052:Spectrometry, X-Ray Emission
chemical_list: D002130:Calcium Phosphates; D057133:Dentin Desensitizing Agents