title: Dental discolouration after thermal treatment.
abstract: Enamel and dentin discolouration have extrinsic and intrinsic origins. Possible causes include pigmented food or drink, caries, clinical chemical treatments, trauma and, high temperature. In the oral cavity, dental hard tissues can be heated when irradiated with high-intensity lasers. This paper, reports initial results on the discolouration of enamel and dentin induced by thermal treatment. The samples used in this work were bovine incisor teeth. Enamel and dentin discolouration were verified using microscopy and transmission spectroscopy. Thermal treatment was carried out at temperatures of 140 and 200 degrees C. The natural transparent aspect of the enamel became opaque after thermal treatment, it whitened following treatment at 140 degrees C, and turned completely opaque after treatment at 200 degrees C. With the same thermal treatment, dentin became light brown after treatment, at 140 degrees C, and the brown pattern was more evident after treatment at 200 degrees C. Although there is no conclusive evidence, non-enzymatic browning, collagen denaturation or oxidation of some chemical component of the dentin, may be intensified or produced by the thermal treatment. In enamel, water loss and the consequent increase in light scattering explain the observed opacity.
authors.affiliation: Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, Av Lineu Prestes, 2242 Cidade Universitária 05508-900, São Paulo, SP Brazil. bachmann@ipen.br
authors.forename: Luciano
authors.initials: L
authors.lastname: Bachmann
authors.forename: Elisa
authors.initials: E
authors.lastname: Thomé Sena
authors.forename: Sandro
authors.initials: S
authors.lastname: Fernando Stolf
authors.forename: Denise
authors.initials: D
authors.lastname: Maria Zezell
mesh_terms: D000818:Animals; D002417:Cattle; D003743:Dental Enamel / Q000737:chemistry; D003804:Dentin / Q000737:chemistry; D006358:Hot Temperature; D007180:Incisor / Q000737:chemistry; D007834:Lasers; D013696:Temperature; D013997:Time Factors; D014075:Tooth Discoloration / Q000209:etiology*