Biomaterial Database

Relationship between laser fluorescence and enamel hypomineralisation. 2008

R A Farah, and B K Drummond, and M V Swain, and S Williams

Department of Oral Sciences, Faculty of Dentistry, University of Otago, New Zealand. farra304@student.otago.ac.nz

OBJECTIVE To study the relation between the mechanical properties of hypomineralised enamel, and its laser fluorescence (LF). METHODS Five extracted teeth with molar-incisor hypomineralisation (MIH) were sectioned longitudinally through the defects and polished to prepare the hypomineralised enamel for testing. Hardness (H) and elastic modulus (E) of enamel were measured using nanoindentation. Measurement recording started from the cervicoenamel junction and proceeded occlusally in increments of 200 microm. Laser fluorescence readings were taken along the same line and at the same sites using a DIAGNOdent pen. RESULTS H, E, and LF readings from cervical enamel were within the expected range for normal sound enamel. After log transformation of the H and E measurements to allow for linear correlation analysis, there was a significant and moderately strong inverse correlation between LF and H or E samples (r (between specimens)=0.59, r (between specimens)=0.39, respectively; p<0.001). CONCLUSIONS This study shows that, in the absence of dental caries, increased DIAGNOdent readings can indicate enamel hypomineralisation. While the increased LF readings in carious enamel are thought to be related to the presence of caries bacterial metabolites, the increased readings in hypomineralised enamel may be related to proteins in the hypomineralised enamel and/or light scattering by the inhomogeneous enamel.

UI	MeSH Term	Description	Entries
D007834	Lasers	An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.	Masers,Continuous Wave Lasers,Pulsed Lasers,Q-Switched Lasers,Continuous Wave Laser,Laser,Laser, Continuous Wave,Laser, Pulsed,Laser, Q-Switched,Lasers, Continuous Wave,Lasers, Pulsed,Lasers, Q-Switched,Maser,Pulsed Laser,Q Switched Lasers,Q-Switched Laser
D008963	Molar	The most posterior teeth on either side of the jaw, totaling eight in the deciduous dentition (2 on each side, upper and lower), and usually 12 in the permanent dentition (three on each side, upper and lower). They are grinding teeth, having large crowns and broad chewing surfaces. (Jablonski, Dictionary of Dentistry, 1992, p821)	Molars
D003732	Dental Caries Activity Tests	Diagnostic tests conducted in order to measure the increment of active DENTAL CARIES over a period of time.
D003743	Dental Enamel	A hard thin translucent layer of calcified substance which envelops and protects the dentin of the crown of the tooth. It is the hardest substance in the body and is almost entirely composed of calcium salts. Under the microscope, it is composed of thin rods (enamel prisms) held together by cementing substance, and surrounded by an enamel sheath. (From Jablonski, Dictionary of Dentistry, 1992, p286)	Enamel,Enamel Cuticle,Dental Enamels,Enamel, Dental,Enamels, Dental,Cuticle, Enamel,Cuticles, Enamel,Enamel Cuticles,Enamels
D003744	Dental Enamel Hypoplasia	An acquired or hereditary condition due to deficiency in the formation of tooth enamel (AMELOGENESIS). It is usually characterized by defective, thin, or malformed DENTAL ENAMEL. Risk factors for enamel hypoplasia include gene mutations, nutritional deficiencies, diseases, and environmental factors.	Enamel Hypoplasia,Enamel Agenesis,Enamel Hypoplasia, Dental,Hypoplasia, Dental Enamel,Hypoplastic Enamel,Agenesis, Enamel,Enamel Ageneses,Enamel Hypoplasias,Enamel, Hypoplastic,Hypoplasia, Enamel
D005453	Fluorescence	The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.
D006244	Hardness	The mechanical property of material that determines its resistance to force. HARDNESS TESTS measure this property.	Hardnesses
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012720	Severity of Illness Index	Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.	Illness Index Severities,Illness Index Severity
D017001	Tooth Demineralization	A tooth's loss of minerals, such as calcium in hydroxyapatite from the tooth matrix, caused by acidic exposure. An example of the occurrence of demineralization is in the formation of dental caries.	Demineralization, Tooth