Mixed dentition space analysis in a Jordanian population: comparison of two methods.
OBJECTIVE
To test the reliability of the Moyers charts and the Tanaka and Johnston equations in Jordanians and to derive coefficients of correlation between the combined mesiodistal widths of the four permanent mandibular incisors and the combined widths of the canine and premolars of the maxillary and mandibular quadrants.


METHODS
The dental models of the dentition of 130 male and 96 female Jordanian subjects (age range is 14-16 years) with complete permanent dentition were randomly selected. The mesiodistal width of the four permanent mandibular incisors, maxillary and mandibular canines, and premolar teeth were measured using a vernier gauge caliper to the nearest 0.1 mm. The actual teeth measurements were then compared with the predicted values derived from the Tanaka and Johnston equations and Moyers probability tables. Correlation and linear regression analyses were performed between the predicted and actual tooth size for Jordanian children and standard regression equations were developed.


RESULTS
Except for the maxillary arch in male subjects, Tanaka and Johnston regression equations underestimated the mesiodistal widths of permanent canines and premolars. On the other hand, there were no statistically significant differences between actual mesiodistal widths of canines and premolars and the predicted widths from Moyers charts at the 65% and 75% level for the lower and upper arches in male subjects and at the 85% level for the upper and lower arches in female subjects. For the newly developed regression equations, the correlation coefficients between the sum of the mandibular four incisors and the sum of the canine and premolars were 0.60 (for lower) and 0.51 (for upper) in male subjects and 0.59 and 0.64, respectively, in female subjects.


CONCLUSIONS
(1) Tanaka and Johnston prediction method was not accurate when applied to a Jordanian population. (2) Moyers method for prediction can be used for Jordanian children at different probability levels for male and female subjects.
Abu Alhaija
E S J
ES
Division of Orthodontics, Jordan University of Science and Technology, Irbid, Jordan.
Qudeimat
M A
MA
D000293:Adolescent; D018912:Arabs; D003724:Dental Arch / Q000033:anatomy & histology*; D003818:Dentition, Mixed; D005260:Female; D006801:Humans; D007597:Jordan; D016014:Linear Models; D008297:Male; D003765:Models, Dental; D009811:Odontometry / Q000379:methods* / Q000706:statistics & numerical data; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D014070:Tooth / Q000033:anatomy & histology*; D019228:Tooth Crown / Q000033:anatomy & histology; D014097:Tooth, Unerupted / Q000033:anatomy & histology