بررسی میزان اعتبار روش Tanaka-Johnston جهت برآورد پهنای مزیودیستال دندان های دائمی نیش و آسیای کوچک در یک نمونه از جمعیت شهر قزوین

Statement of Problem: One of the easiest and most practical methods to predict the size of permanent canines and premolars, is of Tanaka-Johnston, but their research has been only performed on white skin North Europeans and it should be noted that the size of teeth, in various races, differ from each other.Purpose: The aim of this study was to determine the validity of Tanaka-Johnston method, in a sample population taken from Ghazvin city.Materials and Methods: The numbers of 235 pairs of study casts, prepared before any kind of treatment, were selected. The size of lower permanent incisors and permanent canines and premolars of both arches were measured. To analyze the results, "regression analysis" and "t test" were used.Results: Based on the findings obtained from this study, new prediction equations as Y=12.9+0.4(X) and Y=]0.6+0.5(X) were presented for maxilla and mandible, respectively. However, these equations did not differ from Tanaka-Johnston equations statistically.Conclusion: Tanaka- Johnston equations can be acceptably applied for the sample population taken from Ghazvin city, if the predictions are not overestimated.