Marilia Mattar de Amoêdo Campos Velo1, Ana Laura Herrera Farha1, Paulo Sérgio da Silva Santos2, Aymée Shiota1, Simone Zuquerato Sansavino3, Ana Tarsila Souza3, Heitor Marques Honório4, Linda Wang5. 1. Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Al. Dr Octávio Pinheiro Brisolla 9-75 Vila Universitária, Bauru, SP, CEP: 17012-901, Brazil. 2. Department of Surgery, Stomatology, Pathology and Radiology, Bauru School of Dentistry, University of São Paulo, Al. Dr Octávio Pinheiro Brisolla 9-75 Vila Universitária, Bauru, SP, CEP: 17012-901, Brazil. 3. Section of Medical Physics, Radiotherapy Center of the Region of Bauru, Professora Nair Araújo Antunes Street 1050, Bauru, SP, 17033-495, Brazil. 4. Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru School of Dentistry, University of São Paulo, Al. Dr Octávio Pinheiro Brisolla 9-75 Vila Universitária, Bauru, SP, CEP: 17012-901, Brazil. 5. Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Al. Dr Octávio Pinheiro Brisolla 9-75 Vila Universitária, Bauru, SP, CEP: 17012-901, Brazil. wang.linda@usp.br.
Abstract
OBJECTIVES: Post-radiation dental lesions affect mainly the cervical area of the tooth. Until now, there are quite few evidences regarding the effects of radiation exposure on root dentin breakdown. To better understand this effect, we used human root dentin specimens obtained from third molars from similarly aged individuals. MATERIALS AND METHODS: Twenty specimens were analyzed by the surface hardness (SH), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) to evaluate the baseline properties of their root dentin. Other six human teeth were prepared and analyzed by scanning electron microscopy (SEM). Then the specimens were randomly distributed between two groups (n = 13 per group) and irradiated with a total dose of 55 or 70 Gy in a linear accelerator. The percentage of EDX and surface hardness loss (%SHL) were determined based on measurements before and after irradiation. The specimens were also analyzed after irradiation by SEM and XRD. The Ca/P weight ratio was calculated. RESULTS: Based on SEM analysis, radiation exposure induced dehydration of the dentin. The Ca/P weight ratio decreased (p = 0.0045). The %SHL of specimens irradiated with 70 Gy was higher than that of the 55-Gy group (p < 0.05), although even the lower dose induced root dentin breakdown. CONCLUSIONS: Overall, we can state that radiation exposure changes the composition and structure of human root dentin, which detrimentally affect its hardness. CLINICAL RELEVANCE: The changes reported herein might influence the selection of the dental materials and will bring new knowledge in this field to prevent radiation-related caries in root dentin.
OBJECTIVES: Post-radiation dental lesions affect mainly the cervical area of the tooth. Until now, there are quite few evidences regarding the effects of radiation exposure on root dentin breakdown. To better understand this effect, we used human root dentin specimens obtained from third molars from similarly aged individuals. MATERIALS AND METHODS: Twenty specimens were analyzed by the surface hardness (SH), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) to evaluate the baseline properties of their root dentin. Other six human teeth were prepared and analyzed by scanning electron microscopy (SEM). Then the specimens were randomly distributed between two groups (n = 13 per group) and irradiated with a total dose of 55 or 70 Gy in a linear accelerator. The percentage of EDX and surface hardness loss (%SHL) were determined based on measurements before and after irradiation. The specimens were also analyzed after irradiation by SEM and XRD. The Ca/P weight ratio was calculated. RESULTS: Based on SEM analysis, radiation exposure induced dehydration of the dentin. The Ca/P weight ratio decreased (p = 0.0045). The %SHL of specimens irradiated with 70 Gy was higher than that of the 55-Gy group (p < 0.05), although even the lower dose induced root dentin breakdown. CONCLUSIONS: Overall, we can state that radiation exposure changes the composition and structure of human root dentin, which detrimentally affect its hardness. CLINICAL RELEVANCE: The changes reported herein might influence the selection of the dental materials and will bring new knowledge in this field to prevent radiation-related caries in root dentin.
Authors: Roberta Galetti; Alan Roger Santos-Silva; Alberto Nogueira da Gama Antunes; Fabio de Abreu Alves; Marcio Ajudarte Lopes; Mario Fernando de Goes Journal: Clin Oral Investig Date: 2013-12-06 Impact factor: 3.573
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