title: Comparison of two histopathologic methods for evaluating  subcutaneous reaction to mineral trioxide aggregate.
abstract: OBJECTIVE
  One of the most important factors for suitable materials for pulp therapy is biocompatibility. Two histopathologic methods of Cox and Federation Dentaire International (FDI) were used to evaluate inflammation. In Cox method, density of inflammatory cells, tissue reactions like fibrosis, vascular responses like congestion and fibrin extravasation have been used to evaluate inflammatory reactions. The aim of this study was to compare the accuracy of pathologists' interpretations using two different methods.
  
  
  METHODS
  Three pathologists observed the degree of inflammation in 225 histopathologic sections. These sections showed inflammation in subcutaneous connective tissue of rats adjacent to polyethylene tubes, filled with white or gray mineral trioxide aggregate. Empty tubes served as controls. Samples were harvested after 7-, 15-, 30-, 60-, and 90-days. All pathologists examined the sections under a light microscope (Carl Zeiss, Oberkochen, Germany) at ×400 magnifications. Chi-Square test was used to evaluate the difference between inflammation grades when one pathologist used two methods. Cohen's Kappa value was used to measure agreement of three pathologists to recognize the degrees of inflammations when using one of the methods.
  
  
  RESULTS
  There were no significant differences between the two methods when one of the pathologist used these methods to report the degree of inflammation (p=0.054). However, two other pathologists reported significant differences between two methods (p=0.005, p=0.001). In the FDI method, there was an acceptable agreement between first and second, and first and third pathologist in terms of the degree of inflammation, and intermediate agreement existed between the second and third pathologist. With the Cox method, no agreement among the pathologists could be found.
  
  
  CONCLUSIONS
  The results of three pathologists in terms of rating inflammation with the FDI method showed better agreement than with the Cox method. Therefore, FDI method is more reliable than the Cox method to evaluate inflammation.
authors.affiliation: Department of Oral and Maxillofacial Pathology, Dental Faculty, Tabriz University (Medical Sciences), Tabriz, Iran.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Vosoughhosseini
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Lotfi
authors.forename: Monir
authors.initials: M
authors.lastname: Moradzadeh
authors.forename: Amirala
authors.initials: A
authors.lastname: Aghbali
authors.forename: Saeed
authors.initials: S
authors.lastname: Rahimi
authors.forename: Mohammadali
authors.initials: M
authors.lastname: Saghiri
authors.forename: Vahid
authors.initials: V
authors.lastname: Zand
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Mehdipour
authors.forename: Bahram
authors.initials: B
authors.lastname: Ranjkesh
authors.forename: Sirvan
authors.initials: S
authors.lastname: Doosti
mesh_terms: D017607:Aluminum Compounds / Q000009:adverse effects*; D000818:Animals; D017610:Calcium Compounds / Q000009:adverse effects*; D004338:Drug Combinations; D007249:Inflammation / Q000139:chemically induced* / Q000473:pathology*; D008297:Male; D010087:Oxides / Q000009:adverse effects*; D010338:Pathology, Clinical / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D012387:Root Canal Filling Materials / Q000009:adverse effects*; D017640:Silicates / Q000009:adverse effects*; D040521:Subcutaneous Tissue / Q000187:drug effects* / Q000473:pathology*
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate