Comparison of Two Different Histopathologic Evaluation Methods

Methods: Three pathologists observed and registered the degree of inflammation which related to 225 histopathologic sections in subcutaneus connective tissue of rats adjacent to polyethylene tubes, filled with white or gray mineral trioxide aggegate and empty ones, which harvested after 7-, 15-, 30-, 60-, and 90-day intervals. 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 each of the method.

Results: Chi- Square test showed that there was not any significant differences between two methods when one of the pathologist used these methods to report the degree of inflammation (p=0.054), however, Two other pathologists reported significantly different results between two methods (p=0.005, p=0.001). In the FDI method, there are an accepteable agreement between first and second, and first and third pathologist in term of the degree of inflammation and intermidate agreement was existed between second and third pathologist. In Cox method, there was not any agreements between first and second (Kappa value=0.230), first and third (Kappa value=-0.12), and second and third (Kappa value=0.13) pathologists.

Conclusion: FDI method is a more reliable than Cox method in evaluation of inflammation in subcutaneous connective tissue of rat.