Comparison of three mixed dentition analysis methods in orthodontic patients at AKUH

Objective: To compare the actual sum of canine and premolars and that predicted from three mixed dentition prediction methods in orthodontic patients at the Aga Khan University Hospital (AKUH), Karachi. Study Design: Cross-sectional comparative study. Place and Duration of Study: Orthodontic clinic at the Aga Khan University Hospital from June 2002 to December 2007. Methodology: Data were collected using pretreatment records including orthodontic files and plaster casts of 121 orthodontic patients. Digital caliper was used to measure the mesiodistal widths of permanent teeth from 1st molar to 1st molar in mandibular arch, and central incisors and 1st molars in maxillary arch. The methods of Tanaka and Johnston, Moyers, and Bernabé and Flores-Mir were used to predict the mesiodistal widths of the canine and premolars. Comparison between the actual and predicted sum of the mesiodistal widths of canine and premolars was made for each prediction method, using paired sample t-test. Results: There were 45 males and 76 females with average ages of 13.3±1.3 and 13.4±0.8 years respectively. For males statistically significant differences were found for Moyers at the 75th percentile and Bernabé and Flores-Mir method whereas for females only the Bernabé and Flores-Mir's method showed significant results. However, no significant difference was found in both genders for Tanaka and Johnston method. Conclusion: In the studied orthodontic patients for males Moyers 50th percentile and Tanaka and Johnston methods could be used; while for females Moyers 75th percentile and Tanaka and Johnston methods were applicable for mixed dentition analysis.