Biomaterial Database

Ultrastructural changes of human dentin after irradiation by Nd:YAG laser. 2002

Bor Shiunn Lee, and Chun Pin Lin, and Feng Huei Lin, and Wan Hong Lan

Department of Dentistry, National Taiwan University Hospital, Taipei 10016, Taiwan.

OBJECTIVE The use of Nd:YAG laser has been proposed for endodontic treatment. However, its ability to reduce dentin permeability, which is important for the success of root canal treatment, remains controversial. METHODS Nd:YAG laser irradiation was performed in pulsed mode on human dentin. The parameters were: pulse energy (100 mJ), rate (10 pps), and total irradiation time (4 seconds). The crystalline phases, electron diffraction patterns, morphology, and microstructure of specimens after laser irradiation were observed by dark-field emission transmission electron microscope (TEM). RESULTS Three ultrastructural zones could be delineated in the dentin: (1) an outer zone with an ordered columnar structure composed of hydroxyapatite and beta-tricalcium phosphate, (2) an intermediate zone composed of an amorphous substance (about 40-70 nm in diameter), and (3) an inner zone of well-crystallized hydroxyapatite grains. These three zones were free of pores or voids. CONCLUSIONS Our study demonstrated that laser-irradiation might be used to reduce dentin permeability.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D003745	Dental Enamel Permeability	The property of dental enamel to permit passage of light, heat, gases, liquids, metabolites, mineral ions and other substances. It does not include the penetration of the dental enamel by microorganisms.	Enamel Permeability, Dental,Permeability, Dental Enamel
D003804	Dentin	The hard portion of the tooth surrounding the pulp, covered by enamel on the crown and cementum on the root, which is harder and denser than bone but softer than enamel, and is thus readily abraded when left unprotected. (From Jablonski, Dictionary of Dentistry, 1992)	Dentine,Dentines,Dentins
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D028022	Low-Level Light Therapy	Treatment using irradiation with light of low power intensity so that the effects are a response to the light and not due to heat. A variety of light sources, especially low-power lasers are used.	LLLT,Laser Biostimulation,Laser Irradiation, Low-Power,Laser Therapy, Low-Level,Photobiomodulation,Laser Phototherapy,Laser Therapy, Low-Power,Low-Level Laser Therapy,Low-Power Laser Irradiation,Low-Power Laser Therapy,Photobiomodulation Therapy,Biostimulation, Laser,Irradiation, Low-Power Laser,Laser Irradiation, Low Power,Laser Therapies, Low-Level,Laser Therapies, Low-Power,Laser Therapy, Low Level,Laser Therapy, Low Power,Light Therapies, Low-Level,Light Therapy, Low-Level,Low Level Laser Therapy,Low Level Light Therapy,Low Power Laser Irradiation,Low Power Laser Therapy,Low-Level Laser Therapies,Low-Level Light Therapies,Low-Power Laser Therapies,Photobiomodulation Therapies,Photobiomodulations,Phototherapy, Laser,Therapies, Low-Level Light,Therapies, Photobiomodulation,Therapy, Low-Level Light,Therapy, Photobiomodulation