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Radiation therapy alters microhardness and microstructure of enamel and dentin of permanent human teeth

Gonçalves, Ligia Maria Napolitano ; Palma-Dibb, Regina Guenka ; Paula-Silva, Francisco Wanderley Garcia ; de Oliveira, Harley Francisco ; Nelson-Filho, Paulo ; da Silva, Léa Assed Bezerra ; de Queiroz, Alexandra Mussolino

Journal of dentistry, 2014-08, Vol.42 (8), p.986-992 [Periódico revisado por pares]

England: Elsevier Ltd

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Título:
Radiation therapy alters microhardness and microstructure of enamel and dentin of permanent human teeth
Autor: Gonçalves, Ligia Maria Napolitano ; Palma-Dibb, Regina Guenka ; Paula-Silva, Francisco Wanderley Garcia ; de Oliveira, Harley Francisco ; Nelson-Filho, Paulo ; da Silva, Léa Assed Bezerra ; de Queiroz, Alexandra Mussolino
Assuntos: Bond strength ; Cancer therapies ; Cobalt Radioisotopes ; Collagen - radiation effects ; Collagen - ultrastructure ; Colleges & universities ; Dental caries ; Dental Enamel - radiation effects ; Dental Enamel - ultrastructure ; Dentin ; Dentin - radiation effects ; Dentin - ultrastructure ; Dentistry ; Dose Fractionation ; Enamel ; Hardness ; Head & neck cancer ; Humans ; In Vitro Techniques ; Microhardness ; Microscopy, Electron, Scanning ; Microstructure ; Molar - radiation effects ; Molar - ultrastructure ; Permanent dentition ; Radiation therapy ; Radiotherapy ; Radiotherapy Dosage ; Radiotherapy, High-Energy ; Scanning electron microscopy ; Standard deviation ; Teeth
É parte de: Journal of dentistry, 2014-08, Vol.42 (8), p.986-992
Notas: ObjectType-Article-1
SourceType-Scholarly Journals-1
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Descrição: Abstract Objectives To evaluate, in vitro , the effects of ionizing radiation on the mechanical and micro-morphological properties of enamel and dentin of permanent teeth. Methods Enamel and dentin microhardness ( n = 12 hemi-sections) was evaluated at three depths (superficial, middle and deep) prior to (control) and after every 10 Gy radiation dose up to a cumulative dose of 60 Gy by means of longitudinal microhardness. Data were analyzed using two-way analysis of variance and Tukey's test at a significance level of 5%. Enamel and dentin morphology was assessed by scanning electron microscopy (SEM) for semi-quantitative analysis ( n = 8 hemi-sections). Data were analyzed using Kruskal–Wallis and Dunn's or Fisher exact tests at a significance level of 5%. Results The application of ionizing radiation did not change the overall enamel microhardness, although an increase in superficial enamel microhardness was observed. The micro-morphological analysis of enamel revealed that irradiation did not influence rod structure but interprismatic structure became more evident. Dentin microhardness decreased after 10, 20, 30, 50 and 60 Gy cumulative doses ( p < 0.05) compared with non-irradiated dentin, mainly in the middle portion of the tissue. The micro-morphological analysis revealed fissures in the dentin structure, obliterated dentinal tubules and fragmentation of collagen fibers after 30 and 60 Gy cumulative doses. Conclusions Although ionizing radiation did not affect the enamel microhardness of permanent teeth as a whole, an increase in superficial enamel microhardness was observed. Dentin microhardness decreased after almost all radiation doses compared with the control, with the greatest reduction of microhardness in the middle depth region. The morphological alterations on enamel and dentin structures increased with the increase of the radiation dose, with a more evident interprismatic portion, presence of fissures and obliterated dentinal tubules, and progressive fragmentation of the collagen fibers. Clinical significance This study shows that irradiation affects microhardness and micro-morphology of enamel and dentin of permanent teeth. The effects of gamma irradiation on dental substrate might contribute to increased risk of radiation tooth decay associated with salivary changes, microbiota shift and high soft and carbohydrate-rich food intake.
Editor: England: Elsevier Ltd
Idioma: Inglês;Persa

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Radiation therapy alters microhardness and microstructure of enamel and dentin of permanent human teeth

Gonçalves, Ligia Maria Napolitano ; Palma-Dibb, Regina Guenka ; Paula-Silva, Francisco Wanderley Garcia ; de Oliveira, Harley Francisco ; Nelson-Filho, Paulo ; da Silva, Léa Assed Bezerra ; de Queiroz, Alexandra Mussolino

England: Elsevier Ltd

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