جستجوی مقالات مرتبط با کلیدواژه « Tanaka » در نشریات گروه « پزشکی »

It is important to predict mesiodistal crown width of the unerupted permanent canine and premolars in the mixed dentition, which helps to better determine malocclusion and its further development. In this study, 120 pair of dental study casts, belonged to subjects aged between 12-30 years, were selected and measured in the most mesiodistal width of permanent canines and premolars of both jaws, lower permanent incisors, and first upper permanent molars with the accuracy of 0/01 mm. Mesiodistal width of permanent canine and premolars in upper and lower jaws were estimated by new formula based on the permanent first upper molars and lower central incisors and then were compared with Tanaka-johnson formula. The actual mean for sum of the mesiodistal width of permanent canines and premolars in the upper jaw was 21/22 mm and in the lower was 20/98 mm. The mean for sum of mesiodistal permanent canine and premolars were estimated by new formula in upper and lower jaw as 21/64 mm and 21/69 mm respectively. On the other hand, via Tanaka-Johnson formula, the predictions in upper and lower jaw were 22/41 mm and 21/92 mm respectively. Statistical analyses by means of ANOVA and Pearson correlation test revealed significant differences (P<0.001, r = 0.701). Sum of mesiodistal width of unerupted permanent canines and premolars teeth in the Iranian race (in Yazd) was estimated better using the new formula than applying the Tanaka Johnson formula, because of two following reasons: first, the new formula can be used at an earlier age and second, it has a higher accuracy.

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. The aim of this study was to determine the validity of Tanaka-Johnston method, in a sample population taken from Ghazvin city. 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. 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. Tanaka- Johnston equations can be acceptably applied for the sample population taken from Ghazvin city, if the predictions are not overestimated.