title: Histopathological changes in dental pulp of rats following radiotherapy.
abstract: BACKGROUND
  Radiotherapy is one of the oral and pharyngeal cancer treatment methods that can cause damage to the tissues in the radiation area; the purpose of this study is to evaluate the effects of radiotherapy on dental pulp tissue in rats.
  
  
  METHODS
  In this interventional, experimental double-blind study, 30 rats were studied in three groups (n= 10 each). The first group received 12 gray (Gy), the second group received 18 Gy in one session, and the third group was not exposed to radiation (control group). The 5 μm sections of mandibular molar tooth were prepared and stained with hematoxylin and eosin. Samples were studied under optical microscope to evaluate and score inflammation, necrosis, hyalinization, and vascular congestion. The data were coded and analyzed by statistical tests of χ2and Fisher's exact tests. The significant level ofP= 0.05.
  
  
  RESULTS
  In Group 1, necrosis in two cases, inflammation in one case, hyalinization in one case, and vascular congestion in four cases were observed. In Group 2, inflammation in four cases, hyalinization in two cases, and vascular congestion in five cases were observed. In Group 3, inflammation was observed only in one case. In comparison between the groups, no significant differences were observed in inflammation (P> 0.05), necrosis (P> 0.05), and hyalinization (P> 0.05). However, the difference was significant for vascular congestion (P< 0.05).
  
  
  CONCLUSIONS
  Radiotherapy with doses of 12 and 18 Gy had no significant effect on inflammation, necrosis, and hyalinization in all groups; however, the difference was significant for vascular congestion.
authors.affiliation: Department of Endodontics, Dental Faculty, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Zahra Sadat
authors.initials: ZS
authors.lastname: Madani
authors.affiliation: Department of Endodontics, Dental Faculty, Arak University of Medical Sciences, Arak, Iran.
authors.forename: Soheil
authors.initials: S
authors.lastname: Azarakhsh
authors.affiliation: Department of Oral Maxillofacial Pathology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Pouyan Amini
authors.initials: PA
authors.lastname: Shakib
authors.affiliation: Department of Radiology and Radiotherapy, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Masoomeh
authors.initials: M
authors.lastname: Karimi
keywords: Dental pulp; cancer; histology; radiotherapy