Equation for Tooth Size Prediction from Mixed Dentition Analysis for Taiwanese Population: A Pilot Study

Background: In mixed dentition analysis, estimation of the mesiodistal width of unerupted permanent canines and premolars is essential for successful diagnosis and treatment planning. The present study aimed to develop a simple linear equation to predict permanent tooth sizes from mixed dentition analysis for Taiwanese people. Methods: The sample comprised 200 dental casts, derived from Taiwanese patients (100 males and 100 females; age, 12–35 years). Mesial distal tooth widths were measured in dental casts with a digital caliper. A student’s t-test was conducted to detect tooth size correlations with gender-specific differences, as well as intra-arch counterparts. Standard linear regression was conducted to develop a simple equation representing predictions of canine-premolar relationships. Results: All teeth were not significantly different between the left and right sides, regardless of gender and upper or lower arches. In terms of types of teeth, males had larger tooth dimensions in both arches than females. New regression equations for estimating the dimensions of the unerupted canines and premolars in the Taiwanese population were developed. Conclusions: Using a sample of Taiwanese people, new models derived for females and males separately were developed, which should provide highly accurate predictions for unerupted canines and premolars in the Taiwanese population.

Applicability of Two Non-Radiographic Mixed Dentition Analysis Methods in Orthodontic Patients

Background: Using erupted components of a dental arch to estimate the width of the unerupted dental components are the basis of mixed dentition analysis. Non-radiographic mixed dentition analysis employs a regression equation to assess the width of the unerupted canines and premolars. In this study, we assessed the applicability of two non-radiographic methods of mixed dentition analysis in orthodontic patients. Methods: This cross-sectional research was carried out from the records of Ziauddin College of Dentistry, Department of Orthodontics, from November 2019 to March 2020. Pre-treatment dental casts of 120 subjects (60 males and 60 females) aged between 12-30 years undergoing orthodontic treatment were selected. The mesiodistal widths from the left first molar to the right first molar were measured using a digital Vernier caliper on pretreatment dental casts of both arches. Bachman’s and Tanaka-Johnston methods were applied to estimate the widths of canine and premolars. Gender dimorphism for actual and estimated values was assessed using an independent t-test and a paired t-test was applied for the comparison between the actual and estimated mesiodistal widths of canine and premolar. Results: The actual and estimated widths of canine and premolars reported 14.3±1.4 years for males and 13.4±1.2 years for females. In addition, the Bachman’s and Tanaka-Johnston method overestimated the actual widths of unerupted canine and premolar but the difference was statistically insignificant (p≥ 0.05) in both the genders. Conclusion: The two non-radiographic methods were reliable for mixed dentition analysis with minor overestimation between actual and estimated widths (ICC=0.79). This makes both the methods applicable interchangeably in regular clinical practice.

Prediction of Combined Mesiodistal Width of Unerupted Permanent Canine and Premolars using Moyer’s Mixed Dentition Analysis in Nepalese Newar Population

Introduction: Moyer’s probability table is most commonly used to predict the mesiodistal width of permanent canines and premolars in mixed dentition. However, the table was formulated using data from Caucasian population. This study was performed to compare the Moyer’s prediction table with actual value in Nepalese Newar population as ethnicity is one of the important factor to determine teeth width. Materials & Method: Combined mesiodistal width of permanent canine and premolars were measured in 150 study models of Nepalese Newar orthodontic patients (75males and 75 females). The value was compared with the Moyer’s prediction table at all probability level. Result: There was no statistically significant difference between the actual combined width and that predicted from Moyer’s table at 85% probability level for maxilla and at 75% level for mandible in male, at 95% probability level for maxilla and at 85% probability level for mandible in female. Conclusion: Moyer’s probability level can be used to predict the combined mesiodistal width of permanent canines and premolars in Nepalese Newar population but at specific probability level.

A Moyers-féle vegyes fogazati analízis alkalmazhatóságának vizsgálata a magyarországi lakosság körében

Introduction: Moyers mixed dentition analysis is one of the most commonly used prediction methods to estimate the size of the unerupted teeth. By its use, we can determine the severity of tooth size-arch length discrepancies in mixed dentition. Since the tooth size may vary considerably among different ethnic groups, for the most precise estimation of the required space, an analysis based on the individual’s own ethnic group would be recommended. Aim: Our aim was to evaluate the applicability of Moyers mixed dentition analysis for the Hungarian population. Method: Upper and lower study casts of 370 patients were evaluated. The mesiodistal widths of the teeth were measured by using a Pittsburgh digital caliper. The odontometric values obtained were used to calculate actual and predicted values. The actual teeth measurements were then statistically compared to the predicted values derived from Moyers probability tables. Results: Using Moyers analysis, we found significant differences at each percentile between the actual and predictive values in both sexes. In the upper jaw, values for men at the 95th, 85th, 75th, and 65th percentile overestimated the actual values, while for women only the 65th percentile underestimated it. In the lower jaw, all values were overestimated in relation to the actual measurements at all percentiles. Conclusions: Based on our results, Moyers mixed dentition analysis cannot be reliably applied for the Hungarian population. If used, it is recommended to use the Moyers predicted values at the 65th instead of the 75th percentile, as this will result in closer estimation to the actual space requirements. Orv Hetil. 2019; 160(50): 1984–1989.

Comparison and testing the reliability of two non-radiographic techniques of mixed dentition space analysis in Nepalese population

Background & Objectives: Mesio-distal tooth size-arch length discrepancy is one of the major sources of malocclusion. Accurate prediction of space required for unerupted tooth can help in early interception of developing malocclusion. Various methods has been proposed for prediction of mesio-distal tooth size however accuracy of such methods in population groups other than that on which these methods are based remains questionable. The aims and objectives of this study were to test the reliability of Moyer’s and Tanaka Johnston mixed dentition analysis in Nepalese population, to construct prediction tables for Nepalese population if these methods were found not reliable.Materials & Methods: Study models of 77 subjects (31 males,46 females) fulfilling the inclusion criteria were retrieved from department archive. Tooth dimensions were measured using electronic digital caliper. Moyer’s and Tanaka and Jhonston methods were applied to predict the mesio- distal tooth size of canines and premolars. The predicted values were compared with the actual mesio-distal mesio-distal size. A regression equation based on actual canine and premolar mesio-distal dimensions and sum of mandibular permanent incisors was also developed.Results: Independent t-test showed that there was no significant difference between mesio-distal tooth size in males and females. Paired t-test showed that there was no difference in mesio-distal tooth size between right and left sides of the arch. Tanaka – Johnston analysis overestimated the mesio-distal size in both males and females. Moyer’s method at 75% overestimated the mesio-distal size in male and female and the difference were statistically significant while at 50% it underestimated the tooth size in females.Conclusion: Moyer’s and Tanaka and Jhonston method of mesio-distal size prediction are inaccurate when applied in Nepalese population. A new regression equation to predict the size of tooth has been presented.