Original Article 
Corresponding author: Panchatcharam Barkavi ( barkavi.dent@gmail.com ) © 2024 Panchatcharam Barkavi, Mohamed Iqbal, Priyanka Gandhi, Harishma Sivakumar, Kavitha Mathivanan, Kothandaraman Thirivikhraman.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Barkavi P, Iqbal M, Gandhi P, Sivakumar H, Mathivanan K, Thirivikhraman K (2024) Reliability of Moyer’s and Tanaka Johnston’s prediction methods in a nonCaucasian heterogeneous population – a crosssectional study. Folia Medica 66(4): 521527. https://doi.org/10.3897/folmed.66.e126997

Introduction: Mixed dentition analyses are used to determine possible toothsize and archlength discrepancies during the transition from primary to permanent dentition. Prediction methods using a probability table or linear regression equation use the sum of the mesiodistal widths of mandibular permanent incisors to predict the mesiodistal width of unerupted permanent teeth. Racial and sexual variations and sexual dimorphism in tooth size have been reported. The objective of this study is to validate Moyer’s and Tanaka Johnston’s mixed dentition analyses in a contemporary South Indian population.
Materials and methods: 100 pairs of permanent dentition models belonging equally to both sexes with an age range of 12–21 years comprised the sample in which both analyses were done. The predicted width of permanent canines and premolars was compared to the actual width in the study models.
Results: There was a statistically significant difference between the two values for Moyer’s analysis in the mandibular teeth of females (p=0.04), 95% CI −0.605 to −0.969. There was a statistically significant difference between the two values for Tanaka Johnston’s analysis of maxillary teeth (p=0.001), 95% CI 0.863 to 1.370.
Conclusions: Moyer’s analysis shows a statistically significant underestimation in the mandibular arch of females. Tanaka Johston’s analysis shows a statistically highly significant overestimation in the maxilla. Both analyses cannot be reliably applied to the South Indian population.
mixed dentition analysis, nonradiographic methods, prediction methods, validity of Moyer’s prediction method, validity of TanakaJohnston’s prediction method
Preventive and interceptive procedures are integral to early treatment protocols in patients with favorable morphogenetic patterns. Maintaining arch length in these individuals is crucial to making sure the transition from deciduous to permanent dentition is uneventful.^{[1]} Mixeddentition analyses are essential diagnostic tools in this regard. They assess the space available in the arch compared to the space required to accommodate the unerupted permanent canine, first and second premolars.^{[2]} The space required being the sum of the mesiodistal width of an unerupted permanent canine, the first and second premolars are measured by several methods like using radiographs^{[1]}, prediction tables^{[3]}, and linear equations^{[4]}. The radiographic method is the least precise owing to projection and magnification errors.^{[5]} Analysis by Moyer based on prediction tables^{[3]} and Tanaka and Johnston’s equation method^{[4]} are the most frequently used methods to predict the sum of the mesiodistal width of unerupted permanent canines, first and second premolars. Both methods use the mandibular permanent incisors to predict the sum of mesiodistal width of an unerupted permanent canine, first and second premolars. These standards are derived from the AmericanCaucasian population. However, racial variations^{[6, 7]}, secular variations^{[8, 9]}, and sexual dimorphism^{[10]} in tooth sizes have been established. Application of these standards in nonAmerican, nonCaucasian population is questionable. Prediction tables and linear equations for several populations and ethnic groups have been proposed.^{[11–13]} No such standards have been established for the South Indian population. The objective of this study was to validate Moyer’s and Tanaka Johnston’s mixeddentition analyses in a contemporary south Indian population for predicting the sum of the mesiodistal width of permanent canines, first and second premolars.
This is a retrospective, analytical, crosssectional, recordbased study, approved by the institutional review board of the Tamil Nadu Government Dental College and Hospital in Chennai. The sample is from pretreatment maxillary and mandibular permanent dentition study models (Fig.
1. Study models with fully erupted permanent incisors, canines, premolars and first molars on both sides of maxillary and mandibular dental arches. The teeth should have reached the occlusal plane to facilitate accurate measurement.
2. Intact dentition with no proximal caries, restorations, and trauma.
3. Mesial and distal contact points of all teeth should be accessible for sliding calipers.
4. Teeth younger than 21 years of age at the beginning of the study in order to exclude the mesiodistal loss of tooth structure due to physiological attrition.
The mesiodistal width of mandibular incisors, maxillary and mandibular permanent canines, and the first and second premolars was measured using a digital Vernier caliper (0150 mm, INSIZE with 0.01 mm resolution) (Fig.
Statistical analysis was done by IBM SPSS (IBM Corp. Released 2011.IBM SPSS Statistics for Windows, Version 20.0 Armonk, and NY: IBM Corp). Mean and SD were used to summarize the data. Means and standard deviations for the sum of the mesiodistal width of the mandibular incisors and the sum of mesiodistal width of permanent canine and premolars in a quadrant were determined. Means and standard deviations for the predicted width of permanent canines and premolars in both arches were also determined. Initially, the data was checked for normality using the ShapiroWill test. The data was found to be normal, and therefore it was decided to use parametric tests for further comparisons. Predicted and measured values were compared using the Student’s t test. A p value of less than 0.05 was considered statistically significant.
The intraexaminer measurements showed a strong reliability with Cohen’s Kappa value of 0.859 (p=0.002) (Table
Variable  Value  P value 
Cohen’s kappa  0.859  0.002^{*} 
Statistical analysis for comparison of right side and left side mesiodistal width of canines and premolars
Arch  Side  Mean  SD  SEM  P value 
Maxilla  Left  21.6775  1.074  0.107  0.952 
Right  21.6803  1.076  0.107  
Mandible  Left  22.2709  1.240  0.124  0.923 
Right  22.2581  1.241  0.124 
Mean differences between the actual and predicted values of the sum mesiodistal width in the maxilla (females) (Moyer’s analysis).
Mean differences between the actual and predicted values of the sum mesiodistal width in the mandible (females) (Moyer’s analysis).
Variable  Group  Mean  SD  SEM  95% Confidence interval of the difference  P value  
Lower  Upper  
Female  Maxilla  Predicted  21.28  0.331  0.047  −0.06714  −0.37369  0.665 
Actual  21.35  1.02  0.146  
Mandible  Predicted  21.28  0.602  0.086  −0.60531  −0.96916  0.04*  
Actual  21.88  1.13  0.161  
Males  Maxilla  Predicted  22.27  0.595  0.086  −0.29950  −0.71046  0.151 
Actual  22.57  1.29  0.184  
Mandible  Predicted  22.08  0.536  0.079  0.09035  −0.24666  0.59  
Actual  21.99  1.02  0.146 
Mean differences between the actual and predicted values of the sum mesiodistal width in the maxilla (males) (Moyer’s analysis).
Mean differences between the actual and predicted values of the sum mesiodistal width in the mandible (males) (Moyer’s analysis).
Mean differences between the actual and predicted values of the sum mesiodistal width in the maxilla (Tanaka and Johnston’s analysis).
Mean differences between the actual and predicted values of the sum mesiodistal width in the mandible (Tanaka and Johnston’s analysis).
Variable  Group  Mean  SD  SEM  95% Confidence interval of the difference  P value  
Lower  Upper  
Maxilla  Predicted  22.79  0.7030  0.070  0.86365  1.37065  0.001* 
Actual  21.68  1.076  0.107  
Mandible  Predicted  22.29  0.7039  0.070  −0.24726  0.31536  0.81 
Actual  22.26  1.238  0.123 
Nonradiographic mixeddentition analyses to predict the sum of the mesiodistal width of unerupted permanent canines, first and second premolars are based largely on odontometric data of early white North American children of European ancestry. Racial and secular variations, sexual dimorphism exhibited by human dentition makes applicability of these norms in other populations unreliable. Several studies have been carried out in Middle Eastern, African, and European populations.^{[7, 12, 13, 15]} Studies on Indian population are predominantly restricted to North Indian population^{[16–18]} with few in the homogenous South Indian population^{[19–21]}. This study is an attempt to investigate the applicability of Moyer’s and Tanaka Johnston’s mixeddentition analyses in a heterogeneous south Indian population. We restricted the sample age to 21 years to minimize bias attributable to physiological attrition and loss of proximal teeth material. A digital Vernier caliper with 0.01 mm resolution was used to reduce reading errors. Intraexaminer reliability of the study was strong with a Cohen’s kappa score of 0.859. The study found that Moyer’s analysis underestimated the sum of mesiodistal widths of permanent canines, first and second molars, both in the maxilla and the mandible for female samples, with statistical significance only in the mandible. In the male samples, there was underestimation in the maxilla and overestimation in the mandible, with no statistical significance in both arches. Melgaco et al.^{[22]} showed similar results at the 50th and 75th percentile, with statistical significance in both sexes. Philip et al.^{[16]} and Sonahita et al.^{[17]} showed similar results, with statistical significance in both arches. Kommineni et al.^{[19]} in their study on Chennai population found validity in Moyer’s at the 50th percentile alone. A similar finding was reported by Kamatham et al.^{[20]} Dasgupta et al.^{[18]} and Legović et al.^{[23]} found statistically significant overestimation of predicted width. With respect to Tanaka Johnston’s analysis, this study found overestimation in the maxilla and the mandible. This was statistically significant in the maxilla and insignificant in the mandible. The data was not differentiated between sexes in keeping with the original recommendation. This is similar to studies by Legović et al.^{[23]} and Dasgupta et al.^{[18]} While the few studies on Indian population are homogeneous, this study is a composite heterogeneous study that can be extrapolated to the South Indian population as a whole. The sample size is a limitation of this study.
Application of mixeddentition analyses in a nonCaucasian, nonAmerican population based on the sum of the mesiodistal width of mandibular permanent incisors as a predictor requires validation as the norms are CaucasianAmericanbased. This study was conducted with the objective of such validation in a composite South Indian population.
The salient conclusions are:
Moyer’s prediction at the 75th percentile is inaccurate to be applied for a South Indian population.
1. Moyer’s analysis shows a statistically significant underestimation in female mandibles and statistically insignificant underestimation in female maxillae and male maxillae.
2. Moyer’s analysis shows a statistically insignificant overestimation in male mandibles.
3. Tanaka and Johnston’s analysis shows a highly statistically significant overestimation in maxilla and statistically insignificant overestimation in mandible.
Both analyses cannot be reliably applied to the South Indian population, and hence there is a need to frame populationspecific norms. This would require another study with a larger sample size to generate data and apply a possible regression model to make the analyses more reliable for this population.
The authors have no support to report.
The authors have no funding to report.
The authors have declared that no competing interests exist.
Panchatcharam Barkavi: conceptualization, data curation, methodology, project administration, resources, validation, visualization, writing – original draft, writing – review and editing; Mohamed Iqbal: visualization, resources, validation, writing – original draft, writing – review and editing; Priyanka Gandhi: writing – original draft, writing – review and editing; Harishma Sivakumar: writing – original draft, writing – review and editing; Kavitha Mathivanan: writing – original draft, writing – review and editing; Kothandaraman Thirivikhraman: writing – original draft, writing – review and editing.