title: Experiment and simulation of resistance of nanoporous dentin biomaterial to CO₂ laser irradiation.
abstract: The resistance of nanoporous dentin biomaterial to CO₂ laser irradiation was investigated by experiment and simulation for potential tooth hypersensitivity treatment. The controlled parameters including laser power of 0.03-0.150 W, scanning speeds of 11.4-34.2 mm/s and focus/defocus modes were used for studying interaction between laser energy and dentin of human tooth. Most of the dentin specimens were etched after CO₂ laser irradiation with the power larger than 0.12 W at a scanning speed of 11.4 mm/s. Compared with the simulation results of temperature distribution, the maximum temperature at laser powers from 0.12 to 0.15 W is increased from 1961 to 2245°C, which exceeded the melting point (1570°C) of dentin's main content hydroxyapatite (HA). Increasing scanning speed can reduce the linear density of laser output energy for just locally melting porous microstructure of dentin surface without etching. Varying focus mode can also improve the damage of nanoporous dentin microstructure. At parameters of 0.150 W power and 34.2 mm/s scanning speed under defocus operation, laser treatment was successfully performed on the nano-HA coated dentin with well-molten sealing on tubules of porous microstructure at a simulate surface temperature of about 574°C, which was the potential for dentin hypersensitivity cure application.
authors.affiliation: Department of Mechanical Engineering, Center for Micro/Nano Science and Technology, and Advanced Optoelectronic Technology Center, National Cheng Kung University,Tainan, Taiwan.
authors.forename: H Y
authors.initials: HY
authors.lastname: Wang
authors.forename: S L
authors.initials: SL
authors.lastname: Lin
authors.forename: C K
authors.initials: CK
authors.lastname: Chung
authors.forename: S F
authors.initials: SF
authors.lastname: Chuang
mesh_terms: D003198:Computer Simulation; D003804:Dentin / Q000737:chemistry / Q000528:radiation effects*; D017886:Durapatite / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D054020:Lasers, Gas; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D049329:Nanostructures / Q000737:chemistry; D016062:Porosity; D044366:Transition Temperature
chemical_list: D017886:Durapatite