Gender Difference in the Prediction of Crown Widths of Unerupted Permanent Canines and Premolars with Crowded Teeth

Enas Al-Jwarry

doi:10.33899/rden.2020.165424

Abstract

Aims: To determine whether the accuracy of the prediction of the summed widths of unerupted permanent canines and premolars depend on the patient's gender and to examine whether there are differences between sexes in the best combination of independent variables for predicting and to developing new predicting equations for crowding patient for both jaws and both sexes. Materials and methods: The sample consisted of eighty dental casts (40 males and 40 females). The age ranged between (14-22) years and all patients have anterior crowding. The mesiodistal crown diameters of the central incisors, the lateral incisors, the canines, the first premolar, the second premolar, and the first molars in the maxillary and mandibular arch were measured on dental casts. Basal arch lengths and intermolar distances for the upper arch and for the lower arch were also recorded. Predicted sum widths of permanent canines and premolars in both dental arches were calculated using backward multiple regression analysis by using statistical package for social science (SPSS). Results: In the male subject group, there were statistically significant correlations between central incisor and lateral incisor widths in the maxilla (r=0.456) and in the mandible between lower central and lateral incisor widths and lower basal arch length (r=0.682), and in the female subject group, there were statistically significant correlations between the central incisor and the lateral incisor widths, upper first molar, upper basal arch length and upper inter molar distance (r=0.742). For the mandible, lower central and lateral incisor and lower first molar widths (r=724). Also the correlation coefficients (r) and determination coefficients (R2 ) for female group are greater when compared with those for the male subject group. Conclusions: Four regression equations for crowding patients for both gender are establish and the best combination of independent variables for prediction was found to differ between sexes.

Highlights

Successful orthodontic treatment is based on comprehensive diagnosis and treatment planning
Other methods used regression equations and devoted a separated equation to each jaw and sex.(19-20) The aims of this study were to determine whether the accuracy of the prediction of the summed widths of unerupted permanent canines and premolars depends on the patient 's gender and to examine whether there are differences between sexes in the best combination of independent variables for predicting and to development a new predicting equations for crowding patient for both jaws and both sexes
It is important to predict mesiodistal crown diameter of the permanent canines and premolars in the mixed dentition, which helps to determine malocclusion and its further development.(22) Because prediction models are generally applied to patients in the mixed dentition stage to estimate whether sufficient space can be attained in the permanent dentition for spontaneous tooth alignment, in our judgment, evaluating those subjects with obvious tooth crowding, rather than those subjects with normal occlusion, would be more useful for developing prediction models that can be generally applied to patients in the mixed dentition stage.(3) Previous reports (23,24) have documented that the mesiodistal diameters of clinical tooth crowns in subjects with crowding are greater than those of subjects who exhibit normal occlusion

Summary

Introduction

Successful orthodontic treatment is based on comprehensive diagnosis and treatment planning. A few of the fundamental factors in the diagnosis are spacing condition, tooth size, arch form and its dimensions, as well as the tooth arch discrepancies.(1,2) For the patient with mixed dentition accurate prediction of the sum of mesiodistal diameters of clinical crowns of unerupted permanent canines and premolar is indispensable especially in chooswww.rafidaindentj.net. The widely used Tanaka and Johnstan space analysis is a simple method to predict the size of unerupted canine and premolars in mixed dentition with an acceptable accuracy for both jaws and both genders.(8) To improved the accuracy of prediction other variables such as the mesiodistal crown width of maxillary incisors and /or of both maxillary and mandibular molars have been used as predictors.(9-11) Ibrahim et al, found the combination of the sums of lower permanent first molars and upper permanent central incisors was the best predictor for the mesiodistal width of both maxillary and mandibular permanent canines and premolars and the newly proposed prediction equation may be considered clinically useful for mixed dentition.(12) Legovic et al, developed multiple linear regression equations used the buccolingual tooth widths as independent variables in their regression equations.(13) Several simple linear regression equations have been proposed for populations of different ethnic origins.(14- 18).

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Conclusion