Comparison between Tanaka/Johnston and Boston University prediction approaches in a group of Iraqi pupils

Abstract

The purpose of this study was to compare two mixed dentitionprediction methods that do not require the use of periapicalradiographs of the unerupted permanent lower teeth.The two compared methods were the Tanaka/Johnston (T/J)and the Boston University (BU) prediction approaches.Study casts of 52 children (20 males and 32 females)were used; those children were selected from primary and secondaryschools located in different areas of Mosul City. Allsubjects have normal Class I molar relationship.The finding indicated that on the average the T/J approachoverestimated the tooth size of the unerupted teeth (mean+ SD = 1.02 + 1.07 mm). On the other hand, the BU approachunderestimated the tooth size of the unerupted teeth (mean +SD = –0.2 + 1.07 mm). The findings further indicated that therewere statistically significant correlation between the predictedand actual tooth size.The error involved in the use of the prediction equationswas expressed as the standard error of the estimate (SEE).The present findings indicated that the SEE for T/J predictionranged between 0.52–0.63 mm and the corresponding valuesfor BU equation ranged between 0.45–0.68 mm. Dependingon the stage of dental development; i.e., which deciduous andpermanent teeth are present, the T/J approach can be usedwhen the only permanent four mandibular incisors have completelyerupted, whereas the BU approach can be used whenall the deciduous (canines and first molars) are still present.