Accuracy of Four Tooth Size Prediction Methods on Malay Population

Objective. To examine the accuracy of Moyers 50%, Tanaka and Johnston, Ling and Wong and Jaroontham and Godfrey methods in predicting the mesio-distal crown width of the permanent canines and premolars ( ) in Malay population. Materials and Methods. The study models of 240 Malay children (120 males and 120 females) aged 14 to 18 years, all free of any signs of dental pathology or anomalies, were measured using a digital caliper accurate to 0.01？mm. The predicted widths ( ) in both arches derived from the tested prediction equations were compared with the actual measured widths. Results. Moyers and Tanaka and Johnston methods showed significant difference between the actual and predicted widths of ( ) for both sexes. Ling and Wong method also showed statistically significant difference for males, however, there was no significant difference for females. Jaroontham and Godfrey method showed statistical significant difference for females, but the male values did not show any significant difference. Conclusion. For male Malay, the method proposed by Jaroontham and Godfrey for male Thai proved to be highly accurate. For female Malay, the method proposed by Ling and Wong for southern Chinese females proved to be highly accurate. 1. Introduction Crowding and spacing in the mixed dentition should be noted as a large number of cases of malocclusion starts during this stage. These cases may be decreased in severity if treated in the right time [1]. Therefore, it is mandatory to estimate size of the unerupted teeth to propose a good orthodontic treatment plan. Mixed dentition space analysis is considered an essential part of the early orthodontic assessment. By the prediction of the size of unerupted teeth in the mandibular or the maxillary arch, it is possible to calculate the amount of space available for their correct alignment. The treatment plan, based on this calculation, may involve serial extraction, space maintenance, or space regaining. Many methods have been introduced to predict the size of unerupted teeth [2–5]. Moyers prediction tables and Tanaka and Johnston equations have gained wide acceptance [5]. Moyers was the first to predict the widths of the permanent canines, first and second premolars using the sum of the four lower permanent incisors using probability tables. He designed his tables on data derived from a population of Northern European descent. However, the possibility of secular changes within twenty years of producing Moyers tables led Tanaka and Johnston to do their study by repeating Moyers observation but on a new sample of the same