Predicting the size of unerupted canines and premolars of the maxillary and mandibular quadrants in an Iranian population

The aim of this investigation was to examine the accuracy of Moyers probability tables and the Tanaka and Johnston prediction equations in predicting the size of unerupted canines and premolars of the maxillary and mandibular quadrants in an Iranian population and to derive a standard formula for it. METHODS: Out of a sample of 280 subjects, 50 (25 males and 25 females) were selected by specific inclusion criteria. An electronic digital caliper was used to read the nearest 0.01 mm. The teeth measurements derived were compared with those predicted from Tanaka Johnston equations and Moyers probability tables and then standard regression were developed. RESULTS: Tanaka and Johnston regression equations overestimate the mesiodistal width of permanent canines and premolars. There were no statistically significant differences between actual mesiodistal width of canines and premolars and the predicted width from Moyers charts at 65% for the lower and upper arches in male subjects and for the lower arch in females but none of the probabilities has good accuracy for the upper arch in females. For the newly developed regression equations, the correlation coefficients between the sum of the mandibular incisors and the sum of the canine and premolars were 0.709 (for lower) and 0.539 (for upper) in subjects. CONCLUSIONS: Tanaka and Johnston overestimate the actual size for Iranian teeth widths. Moyers method can be used at 65% probability level for male subjects and at the 75% and 85% level for upper arch and the 50% and 65% level for lower arch in female subjects.     

Mixed dentition space analysis in a Jordanian population: comparison of two methods

AIMS: 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.     

The B.S.S.O. M.Orth. prize of the Royal College of Surgeons of England: 1997.

Abstract

Objectives: To test the use of Moyers prediction method and Tanaka and Johnston’s equations for use in a Nepalese population and to construct new probability tables and prediction formulae based on the actual tooth sizes in a sample of the Nepalese population.

Design: Cross-sectional.

Source and setting: Dental, medical and nursing science students at the B.P. Koirala Institute of Health Sciences, Dharan, Nepal.

Subjects and methods: The sample consisted of 100 Nepalese males and 100 females aged between 17 and 23 years. Subjects without any previous orthodontic treatment, fully erupted permanent teeth and with no dental anomalies were recruited. Dental study models were taken and measurements of the mesio-distal widths of teeth were carried out using digital caliper. The measured values were compared with predicted values derived from Moyers method and Tanaka and Johnston equations. Independent t tests were used to examine differences between genders. Correlation coefficients and linear regression equations were used to compare the actual Nepalese tooth widths with predicted values

Results: Moyers method at 50% tends to underestimate the actual width of the canine and premolars in males by 0.3 mm and overestimate the width in females by 0.2 mm. The Tanaka and Johnston method tends to overestimate the actual width of the canine and premolars in both males (0.7 mm) and females 1.0 mm.

Conclusion: The newly developed regression equations are more accurate for prediction of width of unerupted permanent teeth in a Nepalese population. Further studies are required based on larger sample size, to confirm the applicability of the new regression equations proposed.     

Applicability of three tooth size prediction methods for white Brazilians

The objectives of this study were to evaluate the applicability of the methods of Moyers; Tanaka and Johnston; and Bernabé and Flores-Mir to Brazilian individuals and to propose new regression equations using the lower four permanent incisors as predictors for the sum of the widths of the lower permanent canine and premolars. Five hundred dental study casts (250 male and 250 female white patients) were used. The methods of Moyers and Tanaka and Johnston were tested on a sample consisting of 240 female and 223 male patients. The method of Bernabé and Flores-Mir and the new regression equations were based on the complete sample. At the 50th and 75th percentile levels, Moyers' tables tended to underestimate the actual sum of the lower permanent canine and premolars for male and female samples, with statistically significant differences. Although the same statistical significant differences were found when Tanaka and Johnston's and Bernabé and Flores-Mir's methods were used, these differences were not clinically relevant. The new regression equations proposed demonstrate similar correlation and determination coefficients to those found in other studies based on the lower four permanent incisors as predictors. Validating studies (based on similar samples) must be conducted to confirm the applicability and precision of the proposed new regression equations.     

Mixed dentition space analysis in Egyptian children

This study was done to examine the applicability of the Tanaka and Johnston and Moyers’ methods of prediction in Egyptian population and to develop a new prediction method for this specific population if necessary. A total of 325 Egyptian students 145 female, 180 male, mean age 14.4 years, SD±1.1 years were randomly selected from 10 preparatory and secondary schools in Mansoura city, Dakahlia governorate, Egypt during the academic year 2008–2009. The mesiodistal crown diameters of the permanent teeth were measured and compared with the predicted values derived from the Tanaka and Johnston's equations and from Moyers’ probability tables at 35%, 50% and 75%. Significant sexual dimorphism was found in tooth sizes. There were significant differences between the actual measurements and that derived from the Tanaka and Johnston's equation and Moyers’ tables. New linear regression equations were derived for both genders to allow accurate tooth size prediction in Egyptians. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars were found to be 0.78 and 0.89 in male and 0.63 and 0.87 in female, respectively. It can be concluded that there is a limitation in the application of the Tanaka and Johnston's and Moyers’ prediction methods to Egyptian population. The developed prediction equation is more accurate for predicting the mesiodistal widths of unerupted canine and premolars of Egyptian population.     

The lower incisors as a predictor for the size of unerupted canine and premolars in the Iranian ethnicity

The purpose of this study was to find the correlation coefficients between the mesiodistal widths of the permanent mandibular incisors and the permanent canine and premolars for each quadrant and establish a regression equation for prediction of the sum of canine and premolars based on the dimension of the lower incisors. 90 patients 12–20 years old (45 females and 45 males) were selected. The mesiodistal crown diameters of the permanent teeth were measured. The correlation coefficients between the permanent mandibular incisors and the permanent canine and premolars sizes varied from 0.63 to 0.8. An Iranian mixed dentition analysis based on the Tanaka and Johnston method was constructed with linear regression equations; for maxillary arch y = 6.3 + 0.65x (SEE = 0.8 mm) and for mandibular arch y = 5.1 + 0.67x (SEE = 0.8 mm). No significant sexual dimorphism was found in tooth sizes. This study revealed that Iranian population has smaller teeth than white North American. We found that prediction equations of Tanaka and Johnston or Moyers charts cannot accurately predict the size of buccal segment in Iranian population.     

Mixed dentition analysis in a Jordanian population

OBJECTIVE: To examine the applicability of the Tanaka and Johnston method of prediction in a Jordanian population and to develop a new prediction method for this specific population if necessary. MATERIALS AND METHODS: Three-hundred and sixty-seven Jordanians (193 female, 174 male, mean age 15.5 years) were randomly selected to represent 0.1% of 10th grade schoolchildren from Amman, Jordan. The mesiodistal crown diameters of the permanent teeth were measured and compared with the predicted values derived from the Tanaka and Johnston equations. RESULTS: Significant sexual dimorphism was found in tooth sizes. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars were found to be 0.60 and 0.66, respectively. There were significant differences between the actual measurements and measurements derived from the Tanaka and Johnston equations. New linear regression equations were derived for both genders to allow tooth size prediction in Jordanians. CONCLUSIONS: There is a limitation in the application of the Tanaka and Johnston's prediction method to a Jordanian population. It is important to use separate equations for male and female patients.     

Tanaka-Johnston mixed dentition analysis for southern Chinese in Hong Kong

OBJECTIVE: To compare the prediction of unerupted permanent canine and premolar size of a comparable sample size of southern Chinese population with that of the study of Tanaka and Johnston. MATERIALS AND METHODS: Teeth on study casts of an unselected sample from a 12-year-old Hong Kong Oral Health Survey of 12-year-old children (n = 459; 295 males and 164 females) were measured in the mesiodistal dimension. A Chinese mixed dentition analysis based on the Tanaka and Johnston method was constructed with linear regression equations for prediction of the mesiodistal widths of unerupted canines and premolars. Results: Sexual dimorphism was evident between southern Chinese males and females in incisors, canines, and premolars in the mesiodistal dimension. CONCLUSIONS: To predict the space (in mm) required for alignment of unerupted canine and premolars in southern Chinese children, halve the sum of the mesiodistal dimensions of the four mandibular incisors and add the respective constants for males (upper, 11.5; lower, 10.5) or females (upper, 11.0; lower, 10.0).     

Tooth width predictions in a sample of Black South Africans.

Space analysis during the mixed dentition requires prediction of the mesiodistal widths of the unerupted permanent canines and premolars and prediction tables and equations may be used for this purpose. The Tanaka and Johnston prediction equations, which were derived from a North American White sample, is one example which is widely used. This prediction equation may be inapplicable to other race groups due to racial tooth size variability. Therefore the purpose of this study was to derive prediction equations that would be applicable to Black South African subjects. One hundred and ten pre-treatment study casts of Black South African subjects were analysed from the Department of Orthodontics' records at the University of Limpopo. The sample was equally divided by gender with all subjects having Class I molar relationship and relatively well aligned teeth. The mesiodistal widths of the maxillary and mandibular canines and premolars were measured with a digital vernier calliper and compared with the measurements predicted with the Tanaka and Johnston equations. The relationship between the measured and predicted values were analysed by correlation and regression analyses. The results indicated that the Tanaka and Johnston prediction equations were not fully applicable to the Black South African sample. The equations tended to underpredict the male sample, while slight overprediction was observed in the female sample. Therefore, new equations were formulated and proposed that would be accurate for Black subjects.     

Prediction of the size of un-erupted permanent cuspids and bicuspids in a Saudi sample: a pilot study

The purpose of this study was to produce an estimated equation for the prediction of unerupted cuspids and bicuspids for the Saudi population. In this study, dental casts of 65 Saudi subjects (37 males and 28 females) were used. The subjects' age ranged from 18 to 25 years. The mesiodistal width of all permanent teeth was measured. The data was subjected to regression analysis. Results showed the Tanaka and Johnston equations overestimate the predicted tooth width of the un-erupted cuspids and bicuspids in Saudis. Results showed the predicted tooth width of Saudis (males and females) is closer to the 50% level of confidence in Moyer's chart. Multiple regression equations were estimated including the sex factor. Accordingly, two equations were estimated for the prediction of the tooth width of the un-erupted cuspids and bicuspids for the Saudi males and females. Based on the results, it can be concluded the 50% data is more accurate than the commonly used percentage Moyer's table (75%) when both sexes are combined. Further studies are needed to confirm the findings of this study.     

Mixed dentition analysis in a Moroccan population.

The aims of this study were to produce odontometric data for a Moroccan population, to test Tanaka and Johnston and Moyers methods, to derive regression equations and elaborate a specific orthodontic prediction table for Moroccan children. 50 dental casts of Moroccan students (25 males, 25 females, mean age 22.6 years sd 1.35) were used to perform measurements of the greatest mesiodistal widths of all mandibular and maxillary canines and premolars and mandibular incisors with an orthodontic calliper. Significant sexual dimorphism was found in tooth sizes (p = .001). The study revealed close relationships between the total mesiodistal widths of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars. The correlation coefficients (r) and the coefficient of determination (R2) were better sexes combined for the maxilla (r = 0.60 ; R2 = 0.36 ) and for the mandible (r = 0.61 ; R2= 0.37). The regression equations elaborated for males and females were used as a basis for establishing an orthodontic prediction table for Moroccan children.     

Comparison of three nonradiographic methods of mixed dentition analysis in cleft lip and palate patients.

PURPOSE: The purpose of this study was to investigate whether the application of mixed dentition analyses in cleft lip and palate patients differed from noncleft patients and to investigate which method provided the most accurate prediction in cleft lip and palate patients. METHODS: Study casts of 30 cleft lip and palate patients and 30 noncleft patients were used in this study. Each patient had dental casts at two stages of dental development. The methods compared included the Moyers, the Tanaka & Johnston (T/J) and the Boston University (BU) prediction methods. RESULTS: Analyses for both groups indicated that the predicted values yielded by each method were significantly different from one another but were all significantly correlated with actual tooth size. Moyers 50% and BU had the smallest mean difference values and no significant difference between the predicted and actual values for both cleft and noncleft control groups. CONCLUSIONS: Types of cleft had no effect on the size of the mandibular permanent canines and premolars. The application of mixed dentition analyses in cleft lip and palate patients does not differ from noncleft patients. Both Moyers 50% and the BU method have high accuracy and correlation in prediction of unerupted teeth in both groups.     

A new, accurate and fast digital method to predict unerupted tooth size

The sum of the lower incisor tooth width has been proposed as the best predictor for calculating unerupted canine and premolar mesiodistal tooth sizes. The aims of this study were to develop a new, fast, and accurate computerized method to predict unerupted mesiodistal tooth sizes and to determine which reference tooth or combination of reference teeth was the best predictor for canines and premolars in a Spanish sample. The dental casts of 100 Spanish adolescents with permanent dentition were measured to the nearest 0.05 mm with a two-dimensional computerized system. The goal was to predict unerupted canine and premolar mesiodistal tooth sizes using the sizes of the upper central incisor, upper and lower first molar, or a combination of these as a reference and using a specific mesiodistal tooth-size table. The results showed that the Digital Method proposed was very accurate in predicting unerupted canine and premolar tooth size. The combination of the sums of the permanent upper central incisor and the lower first molar was the best predictor for canines and premolars in this sample. Upper arch teeth were better predicted than lower arch teeth. The upper lateral incisor provided the worst predictions.     

Mixed dentition space analysis in a Thai population

This study produced simple linear regression equations to be used for mixed dentition space analysis for males and females, and sexes pooled in a population living in northeastern Thailand. Measurements of teeth were made to within 0.01 mm on the dental casts of 215 boys and 215 girls (mean age 15.7 years). All dentitions were required to be free of any signs of dental pathology or anomalies. It was found that males had significantly larger teeth than females as represented by summations of mandibular incisor, canine, and premolar widths. ANOVA of regression indicated a close relationship between mandibular incisor summation and corresponding summations of canine and premolars. The low coefficients of determination (r2) of the regressions ranged between 0.29 and 0.42, and were higher for females than males, which might be attributable to the ethnic diversity of the sampled population. The regression equations produced predictions of mesio-distal width summations for maxillary and mandibular canine, and premolar arch segments that were slightly different from other reported Asian studies. Moyers' prediction tables at the 50th percentile were found to under-estimate tooth size summation compared with the present investigation. The predictions from simplified regression equations matched well with those of this study for sexes pooled, and for males and females separately.     

New regression equations for mixed dentition space analysis in Nepalese mongoloids

Background

Mixed dentition space analysis methods using regression equations, namely, Moyers’ analysis and Tanaka-Johnston analysis are commonly used around the world. However, the applicability of these analyses among different racial groups have been questioned. The primary objective of this study was to assess the applicability of the Moyers’ and Tanaka-Johnston analyses among Nepalese Mongoloids and to develop regression equations for the same population if needed.

Methods

One hundred (50 males and 50 females) pre-treatment study models of the Nepalese Mongoloid patients undergoing orthodontic treatment were retrieved from the archives of the department of Orthodontics. The mesiodistal widths of mandibular incisors and widths of canines and premolars of all 4 quadrants were measured by a single investigator using a digital caliper to the nearest 0.01?mm. Predicted widths of canines and premolars were obtained using standard Moyers’ and Tanaka-Johnston analyses and then compared with the measured widths.

Results

The measured widths of canines and premolars were significantly different from the predicted widths obtained from Moyers’ and Tanaka-Johnston analyses. Strong and positive correlations were found between the sum of mesiodistal widths of mandibular incisors and the sum of mesiodistal widths of canines and premolars in males (0.73 for maxillary arch and 0.68 for mandibular arch) and females (0.64 for maxillary arch and 0.79 for mandibular arch).

Conclusions

The Moyers’ and Tanaka-Johnston analyses did not accurately predict the mesiodistal width of unerupted canines and premolars for Nepalese Mongoloid population. Hence, new regression equations have been developed for this population. However, validation studies should be conducted to confirm the applicability and accuracy of these equations.

     

Are the lower incisors the best predictors for the unerupted canine and premolars sums? an analysis of a Peruvian sample

The lower permanent incisor tooth width sum has been proposed as the best predictor for the tooth width sums of the unerupted canine and premolars (SPCP) for populations from different ethnic origins. Only two previous studies have refuted it. The purpose of the present study was to determine which sum or combination of sums of permanent tooth widths presented the best prediction capability for the SPCP in a Peruvian sample, to calculate a specific linear regression equation for this population, and to evaluate the clinical significance. A total of 150 children with complete permanent dentitions were selected. Fifty more children were used as a validation sample for the application of a multiple linear regression equation (MLRE). They did not present clinically visible dental caries or proximal restorations and no active or previous orthodontic treatment. Their dental casts were measured to 0.1 mm with a sliding caliper with a Vernier scale. Three-way analysis of variance, Pearson Correlation Test, Fisher Z values and a MLRE were used for the statistical analysis. The combination of the sums of permanent upper and lower central incisors and upper first molars was the best predictor for the SPCP in this sample. A MLRE was calculated including sex and arch as additional predictor variables. The MLRE determination coefficient was 60% with a standard error of 0.8 mm. This new MLRE underestimates (less than 1 mm discrepancy) the actual SPCP in only 7% of the cases on the basis of a validation sample.     

An adaptation of the Moyers mixed dentition space analysis for a Western Cape Caucasian population.

200 dental plaster casts of Western Cape Caucasoid subjects, all of whom were under the age of 21 years, were used in this study. Mesio-distal measurements (MD lengths) were obtained of all the teeth, disregarding the third molars. This data was used to develop regression equations, for maxillary and for mandibular arches, to enable the prediction of the mesio-distal lengths of the canine and two premolars. The study identified the sum of the MD lengths of the permanent lower incisors as the best predictor. It appears that separate predictions for male and female are not warranted. The equations and the predicted values were compared with those of Moyers (1973 and 1988) and some significant differences were found. The Prediction Tables will be useful in analysis of the mixed dentition phase in patients from this population group.     

A comparison of four methods of predicting arch length.

1. Four arch length prediction equations (Nance, Johnston-Tanaka, Moyers, and Hixon-Oldfather) were compared by examining pretreatment casts, pretreatment intraoral radiographs, and posttreatment casts of forty-one patients of mixed-dentition age. 2. A comparison of correlation coefficients and slopes of the predicted arch length versus the actual arch lengths revealed that the Hixon-Oldfather method conformed closest to the ideal. 3. No combination of the four methods produced a more accurate equation than the single most accurate method. 4. Neither the sex of the patient nor the type of occlusion affected the prediction accuracy of any of the four equations. 5. All methods tend to overpredict the arch length size by 1 to 3 mm., with the exception of the Hixon-Oldfather equation, which underpredicted by approximately 0.5 mm. 6. An analysis of the intrainvestigator error showed a very low standard error of estimate for individual tooth measurements and for the prediction values. 7. A variance analysis showed that most of the variation was due to arch length (85%), a slight amount was due to the prediction method (8%), and 6% of the variation was due to the rater. 8. A low correlation was found between space available versus actual discrepancy and space available versus actual arch length. 9. High correlation coefficients were found for the predicted arch lengths when compared with the actual arch lengths. As expected, the correlation coefficients for the predicted widths of only the canines and premolars compared with the actual widths were not quite as high.     

Prediction of mandibular incisor and canine crowding changes in the mixed dentition

To test the hypothesis that preeruptive tooth positions and dental arch parameters might forecast crowding changes, a sample of 47 aboriginal children (26 males, 21 females) was selected stringently on the basis of Class 1 characteristics and an untreated dentition unaffected by caries or attrition. Crowding scores, radiographic relationships of 765E, and dental arch dimensions were evaluated for the mixed dentition (Stage 1, 8.91 +/- 1.05 years) and earliest emergence of the permanent dentition (Stage 2, 12.48 +/- 0.97 years). Changes between the stages were calculated and the sample was divided into two groups, according to an increase (Group 1) or decrease (Group 2) in incisor and canine crowding. Multivariate and multiple regression analyses were used to identify predictors (Stage 1 radiographic and dental arch parameters) of incisor and canine crowding behavior. Dental arch form and tooth size were important factors in measuring the amount of incisor or canine crowding at Stage 1 and Stage 2. Neither the radiographic nor the dental arch predictors proved useful in forecasting crowding changes. Group 2 dental arches tended to be initially narrower, shallower, and more crowded; however, they showed greater molar and canine width expansion and lessened arch depth reduction than Group 1 cases. Many cases showed a reduction in canine crowding from mixed to permanent dentition. This appeared to be largely independent of the observed incisor crowding. Sexual, racial, and individual variations in dentofacial pattern reinforce the need to carefully consider interceptive extraction or space-regaining therapy for each patient because of the unpredictability of crowding behavior during the transition from mixed to permanent dentition.