Mixed Dentition Analysis among a Nigerian Population

Mixed dentition space analysis forms an important aspect of orthodontic diagnosis and treatment planning. A commonly used method involves the use of regression equations to predict the sizes of the unerupted canines and premolars. The objective of this study was therefore to evaluate the accuracy of the Tanaka and Johnston tooth size prediction equations in a Nigerian population. Methodology Mesiodistal tooth widths of teeth from 150 pairs of dental casts, obtained from junior secondary school children (88 females, 62 males) aged between 12 and 16 years old were measured with a digital caliper. The mean sum of the four mandibular incisors was then used to predict the sum of the canines and premolars in one quadrant, using the Tanaka and Johnston equations. These predicted values were then compared statistically with their respective actual measurements from the casts. Results. Results indicated that statistically significant differences (p˂0.05) exist between the actual measurements (Σ 345) and their predicted sizes using the Tanaka Johnston tooth size prediction equations. New prediction equations were therefore formulated for use on Nigerians. Conclusion. The Tanaka and Johnston tooth size prediction equation cannot be used for Nigerians