Mixed dentition analysis in a Senegalese population: elaboration of prediction tables

Estimating the validity of Tanaka-Johnston and Moyer's analysis of a Saudi sample

OBJECTIVES

Accurate estimation of unerupted permanent canines and premolars is a crucial step for effective orthodontic treatment planning during mixed dentition. This study aimed to evaluate the validity of Moyers' charts and the Tanaka-Johnston equation in predicting tooth sizes in a sample of the Madina population in Saudi Arabia and propose a new regression equation.

METHODS

Dental casts from 219 subjects (113 males and 106 females) were analyzed. Actual mesiodistal tooth widths were measured using digital calipers with an accuracy of 0.01 mm. Moyers' and Tanaka-Johnston predictions were compared with actual measurements, and a new set of prediction equations was developed.

RESULTS

Tanaka-Johnston predictions consistently overestimated the actual measurements, exhibiting a difference of 1.20 mm for maxillary canines and premolars and a difference of 1.25 mm for mandibular teeth. The Moyers chart showed gender-specific variations with males aligning with the 50th percentile and females aligning with the 65th percentile for upper arches and the 50th percentile for lower arches. Newly derived linear regression equations were established for predicting the sum of upper and lower canines and premolars for the Madina population.

CONCLUSION

The study highlights limitations in the Moyers and Tanaka-Johnston methods used for the current sample as both methods overestimated tooth sizes. New regression equations were developed to offer a more accurate approach for predicting tooth sizes for the study sample.

Comparison of the different methods of width estimation in unerupted canine and premolars

BACKGROUND

There are different methods for determining the required space for unerupted teeth. However, the accuracy of these techniques varies depending on ethnic differences. Therefore, the current study was performed to compare the accuracy of four methods for estimating the mesiodistal width of unerupted canines and premolars in a population of northern Iran.

METHODS

The present cross-sectional study was conducted on 50 pairs of dental casts of patients aged 12-24 years old. The mesiodistal width of the teeth was measured with a digital caliper by two observers (ICC < 0.9), and the mean value was recorded. The space required for eruption of canines and premolars was obtained by the Tanaka-Johnson formula and the Moyers tables and compared with the actual value by paired t test.

RESULTS

The Tanaka-Johnson formula had overestimation in the maxilla and mandible, which was statistically significant (p < 0.001). The values obtained from the Moyers tables in different confidence levels were not accurate. However, the 65% level for the mandible had almost no difference from the actual value (P = 0.996 and r2 = 0.503). Furthermore, linear regression was obtained based on the total mesiodistal width of the maxillary first molar and mandibular central incisor (maxilla: Yx= 0.613X + 2.23 and mandible: Ym= 0.618X + 1.6) and the total mesiodistal width of the mandibular first molar and maxillary central incisor in each jaw (maxilla: Yx = 0.424X + 5.021 and mandible: Ym = 0.447X + 3.631).

CONCLUSION

The Tanaka-Johnson method was overestimated in the population of northern Iran. The 85% and 75% confidence levels of the Moyers table have the best clinical results for the maxilla and mandible, respectively. Regression based on maxillary first molars and mandibular central incisors has better results.

Mixed Dentition Analysis in and around Kanpur City: An Existential and Illustrative Study

Context

Mixed dentition space analysis helps in determining the discrepancy between the available and required space in each dental arch during the mixed dentition period; further, it helps to diagnose and plan the treatment of developing malocclusion.

Aim

The aim of this study is to evaluate the applicability of Tanaka and Johnston's and Moyer's methods of predicting the size of permanent canines and premolars and compare the tooth size between the right and left sides between males and females, and also to compare the predicted values of mesiodistal widths of permanent canines and premolars from Tanaka and Johnston and Moyer's method with the measured values.

Materials and methods

The sample consisted of 58 sets of study models, of which 20 were girls and 38 were boys, that were collected from the children of the 12-15 year age-group. A digital vernier gauge, whose beaks were sharpened, was used to measure the mesiodistal widths of the individual teeth in order to increase accuracy.

Statistical analysis

The two-tailed paired t-tests were used to assess the bilateral symmetry of the mesiodistal diameter of all measured individual teeth.

Results and conclusion

It was concluded that Tanaka and Johnston's method could not accurately predict the mesiodistal widths of unerupted canines and premolars of children of Kanpur city due to the high variability in estimation, whereas the least statistically significant difference was obtained only at 65% level of Moyer's probability chart for male, female, and combined sample.

How to cite this article

Gaur S, Singh N, Singh R, et al. Mixed Dentition Analysis in and around Kanpur City: An Existential and Illustrative Study. Int J Clin Pediatr Dent 2022;15(5):603-609.

Size estimation of unerupted canines and premolars using various independent variables: a systematic review

INTRODUCTION

Prediction of unerupted permanent teeth is an essential part of orthodontic diagnosis and treatment planning. This prediction is done by mixed dentition space analysis based on the estimation of mesiodistal dimensions of unerupted permanent canine and premolars from already erupted permanent teeth. Permanent mandibular incisors are most commonly used for prediction. Recent literature reveals that mandibular incisors are not accurate predictors and other independent variables have been introduced to make a more accurate and precise prediction. The objective of this paper was to evaluate the literature in light of a variety of independent variables and their predictive accuracy.

METHODS

Electronic databases such as MEDLINE, PubMed, Scopus, Embase, Web of Science, CINAHL Plus were searched to identify articles published until September 2021.

RESULTS

The search resulted in a total of 1098 articles, of which 24 papers met our inclusion criteria and were included in this review. Articles using permanent mandibular incisors only as a predictor were excluded during the eligibility assessment. The results show that various independent variables including mesiodistal and vestibulo-oral dimensions of permanent maxillary and mandibular incisors and molars, molar basal arch length, intermolar distance, maxillary and mandibular arch and gender have been used as predictors to more accurately determine mesiodistal width of unerupted canine and premolars in different populations.

CONCLUSION

Ethnic tooth size variations strongly emphasize the need to determine which independent variable gives a more accurate prediction of unerupted permanent teeth to develop a population-specific prediction model. This will play a significant role in managing space problems and developing malocclusions.

Applicability of moyer's probability tables in north indian population of 16-18 years old

Aims

To determine the applicability of Moyer's probability tables in North Indian population of 16-18 year olds and to formulate a new regression equation for the same group of population.

Setting and Design

Evaluative Study.

Methods and Material

1000 children aged 16-18 years were selected as sample for the measurement of mesiodistal widths of permanent mandibular incisors, maxillary and mandibular canines and premolars using study models. The recorded values were then subjected to statistical analysis.

Statistical Analysis Used

Software Package for Social Sciences (SPSS) software version 22.0.

Results

The actual widths of the canine and premolars showed highly significant differences in maxilla and in mandible (P < 0.001), compared to widths predicted by Moyer's probability table at 75^th percentile.

Conclusion

Moyer's mixed dentition analysis was not an accurate method for prediction in North Indian population as it showed overestimation of tooth sizes. Hence, new regression equation has been formulated for the same.

Permanent Maxillary and Mandibular Central Incisor Width as Predictor of Permanent Maxillary Canine Width in a Kurdish Population: A Pilot Study

BACKGROUND

Estimation of the mesio-distal width of permanent maxillary canines (PMCs) is a critical part of mixed dentition space analysis. The aim of this pilot study is to find a specific prediction equation for the estimation of the mesio-distal width of PMCs depending on the width of permanent maxillary and mandibular central incisors (PMMCIs) in a Kurdish population.

METHODS

A hundred study casts were collected. The mesio-distal widths of the PMMCIs and PMCs were measured by digital caliper. Linear regression tests were applied to find the prediction equation using the sum width of PMMCIs as predictors.

RESULTS

The mean age of the subjects was 17.2 ± 2.39 years old. Statistically significant differences in the mesio-distal widths of PMMCIs and PMCs were found between males and females (p = 0.0001). Furthermore, statistically significant correlations were identified between the widths of PMMCIs and PMCs in both males (r = 0.633, p = 0.0001) and females (r = 0.717, p = 0.0001). Likewise, the mesio-distal width of PMMCIs was found to be a significant predictor of the width of PMCs in both males (R2 = 0.403, p = 0.0001) and females (R2 = 5.14, p = 0.0001). Conclusion: For the first time, regression equations were developed for a Kurdish population and can be useful as a part of a mixed dentition space analysis in Kurdish children.

Applicability of Different Mixed Dentition Analyses among Children Aged 11-13 Years in Chennai Population

Introduction

Mixed dentition is the stage where both primary and permanent teeth are present and hence is the time for developing occlusion. Mixed dentition analysis forms an essential part of an orthodontic assessment. Moyer's method which is commonly used for this analysis is based on data derived from a Caucasian population. Tanaka–Johnston developed prediction tables comparable with that of Moyer's from teeth measurement study models.

Aim

To test the reliability of Moyer's and Tanaka–Johnston's mixed dentition space analyses among children in Chennai.

Materials and methods

The mesiodistal measurements of the mandibular incisors, maxillary canines, and premolars were taken by measuring the greatest distance between the contact points on the proximal surfaces using a dental digital caliper set on dental casts of 1,000 children. Predicted values were obtained using Moyer's probability analysis at the 75th percentile and Tanaka–Johnston method. The statistical analysis for both sexes was done using Student's t test and unpaired t test.

Results

On application of the statistical analysis after the collection of data, it was found that the mean value in males was higher than the actual values in maxillary right and left sides when compared with the mandibular right and left sides while employing Moyer's method. The standard deviation (SD) was higher in the actual values when compared with the predicted values. Statistically significant values were obtained for the maxillary left side and the mandibular left side, but there was no statistical difference in the maxillary and mandibular right sides. Among females, it was found that the actual values had a higher mean value in the maxillary arch when compared with the mandibular arch than the values obtained when Moyer's formula was applied.

Conclusion

Both Moyer's and Tanaka–Johnson's mixed analyses when applied to children in Chennai tended to show that predicted values were higher than actual values with no significant differences observed among the regression equations.

How to cite this article

Ravinthar K, Gurunathan D. Applicability of Different Mixed Dentition Analyses among Children Aged 11–13 Years in Chennai Population. Int J Clin Pediatr Dent 2020;13(2):163–166.

Applicability of Tanaka-Johnston, Moyers, and Bernabé and Flores-Mir Mixed Dentition Analyses in School-going Children of Sri Ganganagar City, Rajasthan (India): A Cross-sectional Study

BACKGROUND

The orthodontic diagnosis and treatment planning are the fundamental goals during the mixed dentition period. Numerous methods have been proposed till date such as Nance method, Moyer's method, Staley-Kerber and Tanaka-Johnston's method, and Bernabé and Flores-Mir method.

AIM

The aim of the study is to determine the mesiodistal widths of the lower permanent canines and premolars from Tanaka-Johnston, Moyers, and Bernabé E and Flores-Mir C mixed dentition analysis and to determine the correlation coefficients and the new prediction equation for Sri Ganganagar population.

SETTING AND DESIGN

A total of 3572 children were clinically examined from the contemporary population of Sri Ganganagar city and Outpatient Department of Pediatric and Preventive Dentistry in Sri Ganganagar, Rajasthan. A total of 150 individuals were randomly selected for the study based on the inclusion and exclusion criteria and were designated as "study samples.

MATERIALS AND METHODS

A total of 150 children aged 11-16 years of Sri Ganganagar city were randomly selected. The mesiodistal width of permanent incisors, canines, premolars, and molars was measured with the help of digital vernier caliper with an accuracy of ±0.01 mm. The measurements of canines and premolars were summed up and compared with those derived from Tanaka and Johnston equations, Moyers probability tables, and Bernabé and Flores-Mir equations.

STATISTICAL ANALYSIS

The data obtained were subjected to statistical analysis using IBM SPSS Statistics Windows version "20.0" using Student's t-test, Pearson correlation coefficient, and Kruskal-Wallis test.

RESULTS

All the three methods overestimated the actual sum of permanent canine and premolars in both the arches in our population. The correlation coefficients and the new regression equations were derived for both maxilla and mandible in males and females for Sri Ganganagar population.

CONCLUSION

The predicted values obtained from all the three methods overestimated the actual values.

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.

[Does gender make a difference in orthodontics? A literature review]

OBJECTIVES

The objective of this literature review is to investigate whether the gender of patients and practitioners makes any difference to orthodontic treatment.

MATERIALS AND METHODS

Sixty-nine articles were selected, the vast majority of which studied patient gender.

RESULTS

Young females are the category of patients which most often apply for orthodontic treatment, probably because of their higher aesthetic demands, despite their objective needs being no greater. Aesthetic, skeletal and dental analyses reveal an obvious dimorphism with larger dimensions in males, especially for the nose, cheekbones, mouth and mandibular canines. Nevertheless, cephalometric angular values do not vary significantly between male and female individuals. Growth is quantitatively greater in males. It also occurs later, as does eruption and maturation of their teeth. Response to the different orthodontic / orthopedic therapies would appear not to differ according to the sex of the patient.

DISCUSSION

These results, however, need to be qualified according to the country concerned, the patients' life style and mind frames, as these can modify or influence the studied parameters.

Applicability of the Moyers' Probability Tables in Adolescents with Different Facial Biotypes

INTRODUCTION

The Moyers' probability tables are used in mixed dentition analysis to estimate the extent of space required for the alignment of canines and premolars, by correlating the mesiodistal size of lower incisors with the size of permanent canines and premolars.

OBJECTIVE

This study intended to evaluate the applicability of the Moyer's probability tables for predicting the mesiodistal space needed for the correct location of premolars and permanent canines non-erupted, in adolescents of the city of Cordoba, Argentina, who show different facial biotypes.

MATERIALS AND METHODS

Models and tele-radiographies of 478 adolescents of both genders from 10 to 15 years of age were analyzed. The tele-radiographies were measured manually in order to determine the facial biotype. The models were scanned with a gauged scanner (HP 3670) and measured by using Image Pro Plus 4.5 software.

RESULTS

According to this study, the comparison between the Moyer´s probability table, and the table created at the National University of Córdoba (UNC) (at 95%, 75%, and 50%) shows that, in both tables, a higher value of mesiodistal width of lower incisors corresponds to a bigger difference in the space needed for permanent canines and premolars; being the need for space for permanents canines and premolars bigger in the UNC´s table. On the other hand, when contrasting the values of mesiodistal space for permanent canines and premolars associated with each facial biotype, the discrepancies between groups were not statistically significant (P >0.05). However, we found differences in the size of the space required according to the mesiodistal width range of the lower incisors for each biotype: a) The comparison of lower-range values, with a mesialdistal width of lower incisors less than 22 mm, the space required for permanent canines and premolars resulted smaller in patients with dolichofacial biotype than in patients with mesofacial and braquifacial biotypes. The latter biotypes have meager differences between them. b) The comparison of mid-range values, with a mesialdistal width of lower incisors from 22 to 25 millimeters, shows that the values of required alignment space are similar in the three facial biotypes. c) Finally, the comparison of upper range values, with a mesialdistal width of lower incisors greater than 25 millimeters, indicates that the space required for dolichofacial biotypes tends to be higher than in mesofacial and brachyfacial biotypes.

CONCLUSION

The Moyer´s probability tables should be created to meet the needs of the population under study, with no consideration of patients' facial biotypes.

Mixed dentition space analysis among Nepalese Brahmins/Chhetris

BACKGROUND

Mixed dentition space analysis forms an important part of orthodontic diagnosis and treatment planning. Regression equations are widely used for mixed dentition analysis which can vary among races. This study aimed to find out the new regression equation in estimating the size of unerupted canines and premolars for Nepalese Brahmins/Chhetris.

METHODS

Hundred Nepalese Brahmins/Chhetris (50 males and 50 females) who met our criteria were selected among the patients attending to the Orthodontic Out-Patient Department, Institute of Medicine, Kathmandu. The mesiodistal widths of all mandibular permanent incisors; maxillary and mandibular canines and premolars were measured and analyzed. The results were also compared with predicted values from the Moyers and the Tanaka and Johnston methods. Correlation and linear regression analyses were performed between the predicted and actual tooth sizes for Nepalese Brahmins/Chhetris and standard regression equations were developed.

RESULTS

No significant differences were observed when the sum of canine and premolars of one quadrant is compared between sides and sex. Significant and high positive correlations were found between the mandibular incisors and the combined mesiodistal widths of the canines and premolars for the maxillary (r = 0.72) and mandibular (r = 0.73) segments. Significant differences were observed between the measured values from this study and from Moyers (50 % and 75 % probability) and Tanaka-Johnston methods.

CONCLUSIONS

The equations and charts commonly used for North American children (50(th) or 75(th) percentile) did not accurately predict for our sample, so new regression equations and tables were developed for Nepalese Brahmins/Chhetris children.

Applicability of Two Universally Accepted Mixed Dentition Analysis on a Sample from Southeastern Region of Andhra Pradesh, India

BACKGROUND

Most of the universally accepted mixed dentition analyses are based on the data derived from northwestern European descent. However, the accuracy of these methods when applied to different ethnic population is questionable.

AIM

The present study is aimed to evaluate the applicability of Tanaka and Johnston (TJ) and Moyers (50(th) and 75(th) percentile) mixed dentition analysis in a sample from south-eastern region of Andhra Pradesh, India.

SUBJECTS AND METHODS

Study models were prepared from a sample of 100 patients (50 males and 50 females) in the age range of 13-15 years. The mesio-distal dimension of the teeth was measured using a Digital Vernier calipers. The actual values of permanent canine and premolars on the casts were compared with the predicted values from TJ and Moyers analysis. The values derived from this study were statistically analyzed using SPSS version 17.0 (IBM, Chicago, USA). Pearson's coefficients were used to evaluate the correlations between the groups of teeth.

RESULTS

Overestimated values were noticed in males and females of both arches with TJ equation; Males showed no significant difference at Moyers 50(th) percentile (50/100), in both the arches where as females showed higher values in mandibular arch and underestimated values in maxillary arch. At Moyers 75(th) percentile, overestimated values were noticed in males for both the arches whereas in females lesser values were observed.

CONCLUSION

As the values showed significant deviation from TJ and Moyers both at 50 and 75 percentile, its applicability to the present population is limited. So, new regression equations were derived.

Mixed dentition space analysis in a Sudanese population

OBJECTIVE

To test the applicability of the Tanaka and Johnston equation for prediction of the mesiodistal width of unerupted permanent teeth in a Sudanese population and to develop a new prediction equation for this specific population if necessary.

DESIGN

A descriptive, cross-sectional study.

SETTINGS

School-based study.

SUBJECTS AND METHODS

Two hundred and fifty subjects (118 males and 132 females) age 13 - 19 years were randomly selected from two public secondary high schools in Khartoum State. Mesiodistal widths of the upper and lower permanent canines, first and second premolars (CPM) as well as the mandibular permanent incisors (MPI) were measured manually on the dental casts using a digital caliper. The predicted values of the mesiodistal widths were statistically compared with the respective actual sum of the canine and premolars of the same quadrant.

RESULTS

Moderate correlation coefficients were found between the sum of the mesiodistal width of the MPI and the sum of the CPM in males (0.618 for mandibular arch and 0.626 for maxillary arch) and females (0.726 for mandibular arch and 0.680 for maxillary arch). A low coefficient of determination was recorded (0.45 and 0.48) in both jaws for combined genders.

CONCLUSIONS

The Tanaka and Johnston equations overestimated the actual mesiodistal width of CPM in both arches for males and females. New prediction equations with more accurate regression parameters were proposed for the Sudanese population.

Prediction of canine and premolar size using the widths of various permanent teeth combinations: A cross-sectional study

AIMS

To suggest the best predictor/s for determining the mesio-distal widths (MDWs) of canines (C) and premolars (Ps), and propose regression equation/s for hitherto unreported population.

METHODS

Impressions of maxillary and mandibular arches were made for 201 children (100 boys and 101 girls; age range: 11-15 years) who met the inclusion criteria and poured with dental stone. The maximum MDWs of all the permanent teeth were measured using digital vernier caliper. Thirty-three possible combinations (patterns) of permanent maxillary and mandibular first molars, central and lateral incisors were framed and correlated with MDWs of C and Ps using Pearson correlation test.

RESULTS

There were significant correlations between the considered patterns and MDWs of C and Ps, with difference noted between girls (range of r: 0.34-0.66) and boys (range of r: 0.28-0.77). Simple linear and multiple regression equations for boys, girls, and combined sample were determined to predict MDW of C and Ps in both the arches.

CONCLUSIONS

The accuracy of prediction improved considerably with the inclusion of as many teeth as possible in the regression equations. The newly proposed equations based on the erupted teeth may be considered clinically useful for space analysis in the considered population.

Validity of Moyers Mixed Dentition Analysis and a New Proposed Regression Equation as a Predictor of Width of Unerupted Canine and Premolars in Children

INTRODUCTION

The Moyer's mixed dentition analysis forms an essential part of diagnostic procedures to determine adequacy of the space available for the erupting permanent teeth. However, its reliability among different racial groups has been questioned.

OBJECTIVES

The objectives of this study were to test the reliability of Moyer's method and to produce new regression equation for Bangalore population for predicting the mesiodistal diameters of the unerupted permanent canines and premolars.

MATERIALS AND METHODS

Data was collected from study models of 400 randomly selected Bangalore subjects aged 13 to 16 years with fully erupted, intact dentitions and no significant malocclusion. The mesiodistal widths of the incisors, canines and premolars of both arches were measured. This data was then utilized to predict the mesiodistal widths of canines and premolars and further compared with Moyer's table.

CONCLUSION

It was found that 50% is more applicable to boys and 75% to girls. The canine premolar segment in both arches is statistically larger in men than in women (p<0.05). New regression equation was formulated, the accuracy of which needs to be evaluated further in a larger sample.

New regression equations for predicting human teeth sizes

INTRODUCTION

The aims of the study were; to evaluate the applicability of the Moyers and Tanaka-Johnston Methods to individuals with a Spanish ancestry, 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, and to compare the new data to those from other populations.

METHODS

A total of 359 Spanish ancestry adolescents were selected. Their dental casts were measured using a 2D computerized system. Real teeth measurements were compared with those predicted using Moyers probability tables and Tanaka and Johnston equations, and standard regression equations were then developed.

RESULTS

Results showed that Upper and Lower Canine and Premolar (UCPM, LCPM) predictions are quite different depending on the used method. Moyers tables can only be validly applied to a 75% percentile for the mandible in both, males and females, 85% in males and 90-92% in females.

CONCLUSIONS

Moyers predictions tend to underestimate UCPM and LCPM whereas Tanaka-Johnston predictions tend to overestimate them. Equations for estimating the combined width of the unerupted canine and premolars were; Male: UCPM = 12.68 + 0.42 LI and LCPM = 11.71 + 0.44 LI. Female: UCPM = 12.06 + 0.43LI and LCPM = 10.71 + 0.46 LI.

How to test validity in orthodontic research: a mixed dentition analysis example

INTRODUCTION

The data used to test the validity of a prediction method should be different from the data used to generate the prediction model. In this study, we explored whether an independent data set is mandatory for testing the validity of a new prediction method and how validity can be tested without independent new data.

METHODS

Several validation methods were compared in an example using the data from a mixed dentition analysis with a regression model. The validation errors of real mixed dentition analysis data and simulation data were analyzed for increasingly large data sets.

RESULTS

The validation results of both the real and the simulation studies demonstrated that the leave-1-out cross-validation method had the smallest errors. The largest errors occurred in the traditional simple validation method. The differences between the validation methods diminished as the sample size increased.

CONCLUSIONS

The leave-1-out cross-validation method seems to be an optimal validation method for improving the prediction accuracy in a data set with limited sample sizes.

Applicability of the Tanaka-Johnston and Moyers mixed dentition analyses in Northeast Han Chinese

OBJECTIVES

To assess applicability of the Tanaka-Johnston and Moyers prediction methods in a Han ethnic group from Northeast China and to develop prediction equations for this same population.

DESIGN

Cross-sectional study.

SETTING

Department of Orthodontics, School of Stomatology, Jiamusi University, Heilongjiang, China.

PARTICIPANTS

A total of 130 subjects (65 male and 65 female) aged 16-21 years from a Han ethnic group of Northeast China were recruited from dental students and patients seeking orthodontic treatment. Ethnicity was verified by questionnaire.

MATERIAL AND METHODS

Mesio-distal tooth width was measured using Digital Vernier calipers. Predicted values were obtained from the Tanaka-Johnston and Moyers methods in both arches were compared with the actual measured widths. Based on regression analysis, prediction equations were developed.

RESULTS

Tanaka-Johnston equations were not precise, except for the upper arch in males. However, the Moyers 85th percentile in the upper arch and 75th percentile in the lower arch predicted the sum precisely in males. For females, the Moyers 75th percentile predicted the sum precisely for the upper arch, but none of the Moyers percentiles predicted in the lower arch.

CONCLUSIONS

Both the Tanaka-Johnston and Moyers method may not be applied universally without question. Hence, it may be safer to develop regression equations for specific populations. Validating studies must be conducted to confirm the precision of these newly developed regression equations.

Evaluation of mixed dentition analyses in north Indian population: A comparative study

INTRODUCTION

Mixed dentition regression equations analyses (Moyers, Tanaka-Johnston) are based on European population, reliability of these methods is questionable over other population.

MATERIALS AND METHODS

The present study was conducted on total 260 study models. This study was done in two phases. In the first phase, linear regression equations were made. In the second phase, comparison of actual values of sum of mesiodistal width of canine, first and second premolars with the predicted values proposed by Moyers, Tanaka-Johnston, and the new proposed mixed dentition analysis for North Indian population were made.

RESULTS

Set of four linear regression equations for predicting sum of mesiodistal width of permanent canine, first premolar and second premolar in North Indian population from sum of mesiodistal width of mandibular incisors and mandibular first molars, were proposed as; (a) for males, maxillary arch, Y = 2.9 + 0.40X, (b) mandibular arch Y = 3.91 + 0.37X (c) for females, maxillary arch Y = 0.56 + 0.45X (d) mandibular arch Y = 1.14 + 0.42X. Moyers and Tanaka-Johnston, mixed dentition analysis, is found to be overestimating the mesiodistal width of unerupted canine and premolars in North Indian population.

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

AIMS

To evaluate the reliability of Tanaka and Johnston and Moyer's (75th percentile) mixed dentition prediction methods in Kodava population sample, to formulate regression equations for predicting the mesiodistal widths of unerupted canines and premolars and to construct probability tables for the Kodava population.

SETTINGS AND DESIGN

Data was obtained from Kodava subjects visiting the clinics for routine dental check up.

MATERIALS AND METHODS

Dental models of 30 male and 30 female Kodava subjects (age range is 16 - 23 yr) were used. Teeth measured included mandibular permanent incisors, maxillary and mandibular permanent canines, first and second premolars. Digital caliper calibrated to 0.01mm was used to record mesiodistal dimensions. The actual teeth measurements were then statistically compared with the predicted values derived from the Tanaka and Johnston's equations and Moyers probability tables at the 75(th) percentile.

STATISTICAL ANALYSIS USED

Descriptive statistics including means, standard deviations were calculated for the actual and predicted tooth sizes. Student's t-tests were performed to compare the differences between the measured mesiodistal widths of canine, first and second premolars and the predicted values derived from Moyers. Correlation and regression analysis were performed to formulate standard regression equations.

RESULTS

Tanaka and Johnston prediction equations overestimated the mesiodistal widths of permanent canines and premolars in both the arches. Moyers 75(th) percentile also overestimated the actual measurements except for the maxillary arch in female subjects. The percentage of overestimation was more for Tanaka - Johnston prediction method than that of Moyers (75(th) percentile). Correlation and regression analysis were performed between the predicted and actual tooth size and standard regression equations were developed for the Kodava population. Probability tables were also constructed from the data obtained.

CONCLUSION

The data from present study illustrates the limitation of Tanaka and Johnston regression equations and Moyer's (75(th) percentile) chart when applied to Kodava population. From this data, regression equations and probability tables were derived for tooth size prediction for Kodava population. This would be more accurate when applied to local children of Kodava community.

Proposed regression equations for prediction of the size of unerupted permanent canines and premolars in Yemeni sample

OBJECTIVE

The aim was to formulate a prediction regression equation for Yemeni and to compare it with Moyer's method for the prediction of the size of the un-erupted permanent canines and premolars.

SUBJECTS AND METHODS

Measurements of mesio-distal width of four permanent mandibular incisors, as well as canines and premolars in both arches were obtained from a sample of 400 school children aged 12-14 years old (13.80 ± 0.42 standard deviation) using electronic digital calliper. The data were subjected to statistical and linear regression analysis and then compared with Moyer's prediction tables.

RESULTS

The result showed that the mean mesio-distal tooth widths of the canines and premolars in the maxillary arch were significantly larger in boys than girls (P < 0.001), while, in the mandibular arch, only lateral incisors and canines were also significantly larger in boys than in girls (P < 0.001). Regression equations for the maxillary arch (boys, Y = 13.55 + 0.29X; girls, Y = 14.04 + 0.25X) and the mandibular arch (boys, Y = 9.97 + 0.40X; girls, Y = 9.56 + 0.41X) were formulated and used to develop new probability tables following the Moyer's method. Significant differences (P < 0.05) were found between the present study predicted widths and the Moyer's tables in almost all percentile levels, including the recommended 50% and 75% levels.

CONCLUSIONS

The Moyer's probability tables significantly overestimate the mesio-distal widths of the un-erupted permanent canine and premolars of Yemeni in almost all percentile levels, including the commonly used 50% and 75% levels. Therefore, it was suggested with caution that the proposed prediction regression equations and tables developed in the present study could be considered as an alternative and more precise method for mixed dentition space analysis in Yemeni.

Predicting the size of unerupted canines and premolars using primary maxillary first molar

AIM

One of the most important aspects of interceptive orthodontic diagnosis and treatment planning is space analysis. To date all methods use the size of permanent teeth to predict the dimensions of unerupted teeth. The aim of this study was to predict the permanent teeth size using maxillary primary first molar.

METHODS

The size of primary maxillary first molars and permanent canines and premolars of 80 subjects was measured on their dental casts. Regression equations were determined between the size of primary maxillary first molars and permanent canines and premolars.

RESULTS

The new regression equations for predicting permanent tooth size in the maxilla and mandible were, respectively, Y = 2.2X + 13 and Y = 2.4X + 9.5 among females and Y = 2.7X + 5.5 and Y = 2.4X + 9.5 among males.

CONCLUSIONS

The results show that the primary maxillary first molar size can be used to predict the size of unerupted permanent teeth.

Mixed dentition analysis - Applicability of two non-radiographic methods for Chennai school children

AIM

To evaluate the applicability of the Tanaka and Johnston (1974) and Moyers (1988) methods in predicting the size of permanent canines and premolars in Chennai school children.

MATERIALS AND METHODS

470 sets (127 female and 343 male) of cast models were included in the sample. Mesio-distal (m-d) widths of all teeth from left to right first molars were measured and compared with the predicted values derived from Tanaka and Johnston and Moyers methods.

RESULTS

There was significant bilateral symmetry and sexual dimorphism in teeth sizes seen in both the sexes. Sum of the m-d diameter of permanent mandibular incisors can be used reliably to predict the sum of m-d diameters of unerupted canines and premolars.

CONCLUSIONS

Tanaka and Johnston's method cannot accurately predict the m-d widths. Moyers' prediction tables can be used to estimate the m-d widths of unerupted canines and premolars closer to 50% probability level.

Prediction of unerupted canines and premolars in a Syrian sample

BACKGROUND

The current study aimed to evaluate the applicability of the methods of Moyers and of Tanaka and Johnston to estimate the mesiodistal widths of permanent canines and premolars in Syrian individuals, to determine whether the predicting equations differ by sex, and to develop more accurate regression equations using various teeth groups as predictors.

METHODS

A total of 670 pretreatment pairs of casts belonging to 342 female patients and 328 male patients were selected from the archives of orthodontic clinics in Damascus University and Al-Baath University. All relevant teeth were measured to the nearest 0.01 mm. Paired t tests were used to test the applicability of the Moyers method and the Tanaka and Johnson equation on Syrian individuals. New regression equations were constructed.

RESULTS

The predicted values of permanent canines and premolars derived from Moyers' charts at the 50th percentile levels tended to underestimate the actual values for the male subjects but were comparable to the actual values for the female subjects. However, the predicted values derived at the 75th percentile levels tended to be comparable to the actual values for the male subjects and to overestimate the actual values for the female subjects. The predicted values calculated by Tanaka and Johnston's equations tended to overestimate the actual values in both study groups.

CONCLUSIONS

The Moyers method was more accurate for the mixed dentition analysis for Syrian individuals. However, the proper percentile level is determined by sex. The use of the equations constructed using the Syrian sample is advised.

Applicability of Moyers analysis in mixed dentition: A systematic review

INTRODUCTION: Moyers analysis is widely used for analyzing mixed dentition, however, the accuracy of its theoretical probability tables has been recently questioned. Taking into consideration the fact the mixed dentition analysis is of paramount importance to precisely determine the space needed for alignment of canines and premolars, this research aimed at objectively assessing in the literature such an important step for orthodontic diagnosis. METHODS: A computerized search involving articles published on PubMed and Lilacs between 1990 and September, 2011 was conducted in accordance with the method described in the Cochrane 5.1.0 handbook. RESULTS: The research resulted in a sample composed of 629 articles. The inclusion criteria were: Articles using the Moyers analysis with a sample greater or equal to 40 patients. Conversely, the exclusion criteria were: Dental casts of patients with syndromes or oral cleft, researches conducted with a literature review, only, or clinical case reports and researches conducted before 1990. For this systematic review, 19 articles were selected. CONCLUSION: Based on the literature available, we can conclude that the Moyers mixed dentition analysis must be carefully used, since the majority of the articles analyzed showed that the probability of 75% was not as accurate as expected, leading to the need of adapting the probability levels depending on the study population.

New regression equations for mixed dentition space analysis in an Iranian population

AIMS

Prediction of the mesiodistal crown width of unerupted canines and premolars is an important aspect of mixed dentition analysis. The accuracy of Tanaka-Johnston equations, the most commonly method, is questionable when it is applied to different ethnic groups. In this study, we aimed to develop a new regression equation for this prediction in an Iranian population.

MATERIALS AND METHODS

The dental casts of 120 Iranian subjects with complete permanent dentition were selected. Mesiodistal crown widths of teeth were measured with digital caliper. In the first part of the study, the correlation and linear regression equations between four mandibular incisors and the canine-premolars segments of both arches were developed (modified Tanaka-Johnston equation). In the second part, as a new method, correlation and linear regression equations were developed between the sum of mandibular central incisors-maxillary first molars and the canine-premolars segments.

RESULTS

It was found that the correlation coefficients between the sum of mandibular central incisors-maxillary first molars and the maxillary and mandibular canine-premolars segments were higher (r = 0.66, 0.68 respectively) than the one between the four mandibular incisors and the canine-premolars segments (r = 0.58. 0.64).

CONCLUSION

New linear regression equations were derived. In this study, the sum of mandibular central incisors and maxillary first molars was better predictor for unerupted canines and premolars. This novel approach allows the prediction of width of unerupted canines and premolars to take place at earlier age.

CLINICAL SIGNIFICANCE

Using the new method, orthodontists could take advantage of mixed dentition analysis at earlier age. Moreover, to test the derived equations on a larger sample size and in other ethnicities is highly recommended.

A new proposed regression equation for mixed dentition analysis using the sum of permanent mandibular four incisors and first molar as a predictor of width of unerupted canine and premolars in a sample of North Indian population

OBJECTIVE

The objective of this study was to establish a new regression equation for North Indian and to compare and correlate the predicted width of unerupted canine and premolars obtained from the proposed regression equation of the present study in the North Indian population sample, Moyer's prediction table and also from Melgaco regression equation with the actual width; in order to check the applicability of various methods of mixed dentition analysis for the North Indian population.

MATERIALS AND METHODS

The sample consisted of 200 dental casts obtained from the North Indian patients and students which consists of 100 males and 100 females with the average age of 20.12 ± 4.70 years for males and 19.54 ± 3.16 years for females. Mesiodistal tooth widths of mandibular arch from permanent right first molar to left first molar were measured with an electronic digital caliper. Student t-test was used for comparison and Pearson's correlation coefficient was used to correlate the actual sum and the predicted width of the permanent mandibular canines and premolars obtained from various methods.

RESULTS

The difference between the actual and predicted width was statistically insignificant using the regression equation obtained for the North Indian sample population (correlation r = 0.78) in contrast to the significant difference with predicted width obtained from Melgaco equation (r = 0.61) and Moyer's prediction table (r = 0.42).

CONCLUSIONS

A new proposed regression equation for the North Indian population was established. Amongst the three regression equations devised, the proposed regression equation formulated in the present study; gave the most accurate results confirming racial variation in tooth size. This method is considered as an easy and practical way to predict the size of unerupted canines and premolars.

Prediction of width of un-erupted incisors, canines and premolars in a Ugandan population: a cross sectional study

BACKGROUND

Accurate prediction of the space forms an important part of an orthodontic assessment in the mixed dentition. However the most commonly used methods of space analysis are based on data developed on Caucasian populations. In order to provide more accurate local data we set out to develop a formula for predicting the widths of un-erupted canines and premolars for a Ugandan population and to compare the predicted widths of the teeth from this formula with those obtained from Moyers' tables, and Tanaka and Johnston's equations.

METHODS

Dental casts were prepared using mandibular and maxillary arch impressions of 220 children (85 boys/135 girls) aged 12-17 years recruited from schools in Kampala, Uganda. The mesio-distal width of the mandibular incisors, mandibular and maxillary canines and premolars were measured with a pair of digital calipers. Based on regression analysis, predictive equations were derived and the findings were compared with those presented in Moyers' probability tables, and Tanaka and Johnston's equations.

RESULTS

There were no statistically significant differences between the tooth widths predicted by our equations and those from Moyers' probability tables at the 65th and 75th percentile probabilities for the girls and at 75th level in boys in the mandibular arch. While in the maxillary arch no statistically significant differences at the 75th and 95th levels were noted in girls. There were statistically significant differences between predicted tooth sizes using equations from the present study and those predicted from the Tanaka and Johnston regression equations.

CONCLUSIONS

In this Ugandan population, Moyers' probability tables could be used to predict tooth widths at specific percentile probabilities, but generally, Tanaka and Johnston technique tends to overestimate the tooth widths.

Reliability of permanent mandibular first molars and incisors widths as predictor for the width of permanent mandibular and maxillary canines and premolars

AIM

Preventive measures are necessary to prevent a potential irregularity from progressing into a more severe malocclusion. The determination of the tooth size-arch length discrepancy in mixed dentition requires an accurate prediction of the mesiodistal widths of the unerupted permanent teeth.

MATERIALS AND METHODS

For the study, 200 subjects in the age group of 16-25 years were selected from various colleges of M. M. University. The mesiodistal width of permanent mandibular incisors, first molars, canines and premolars of both arches were measured on the subject cast using an electronic digital caliper. Statistical analysis showed a significant difference between mesiodistal tooth widths of males and females. Linear regression equation was determined to predict the sum of mandibular and maxillary permanent canines and premolars using mandibular first molars plus the four mandibular incisors as predictors.

RESULTS

There was no significant difference between the actual and predicted width of sum of permanent canines and premolars using regression equations. The predicted widths of both arches using Tanaka and Johnston equations showed significant differences. Determined regression equations for males were accurate in male samples and determined regression equation for females were accurate in female samples for both arches.

Development of a prediction equation for the mixed dentition in a Pakistani sample

INTRODUCTION

Regression equations are widely used for mixed dentition analysis. However, estimations from these equations can vary in different population groups. The aim of this study was to produce simple linear equations and tables for Pakistani children.

METHODS

Two hundred subjects of Pakistani descent who met our criteria (ages, 13-15 years; 100 boys, 100 girls) were selected from local schools. The mesiodistal widths of all mandibular permanent incisors, canines, and premolars were measured and analyzed by using paired t tests. The results were also compared with predicted values from the Moyers and the Tanaka and Johnston methods. Correlation and linear regression analyses were performed between the predicted and actual tooth sizes for Pakistani children, and standard regression equations were developed.

RESULTS

No significant differences were observed for measured canine and premolar antimeres and sex. Significant and high positive correlations were found between the mandibular incisors and the combined mesiodistal widths of the canines and premolars for the maxillary (r = 0.65; P <0.001) and mandibular (r = 0.59; P <0.001) segments.

CONCLUSIONS

The equations and charts commonly used for North American children (75th percentile) did not accurately predict for our sample. The regression equations and tables developed in this study can be used for orthodontic treatment planning for children in Pakistan.

Demonstration of a sex difference in the predictability of widths of unerupted permanent canines and premolars in a Japanese population

OBJECTIVES

(1) To identify any differences in the accuracy of the prediction of the summed widths of unerupted permanent canines and premolars for males vs females and, if differences are identified, (2) to examine the sex differences in the best combination of independent variables and (3) to evaluate the practical accuracy using our models for both sexes, respectively.

MATERIALS AND METHODS

Records for 200 orthodontic patients (100 males and 100 females) with discernible tooth crowding in the permanent dentition were selected. Mesiodistal tooth crown widths, dental arch widths, and basal arch lengths were measured. Predicted sum widths of permanent canines and premolars in both dental arches were calculated using stepwise regression analysis.

RESULTS

Among male subjects, the best combinations of independent variables were the widths of the upper central and lateral incisors (U1, U2) and the first molar (U6) for the maxilla (R(2) = 0.615) and the mandible, lower central and lateral incisors (L1, L2), and the first molar (L6) (R(2) = 0.685), whereas in females, the best combinations for prediction were found to be U1, U2, U6, and the maxillary arch width for the maxilla (R(2) = 0.429) and L1, L2, L6, and the basal arch length for the mandible (R(2) = 0.426). Correlation coefficients between each independent and dependent variable in the female subject group were found to be weaker than those for the male subject group.

CONCLUSIONS

We found the sex differences in the accuracy of prediction and the best combination of independent variables for predicting the summed widths of unerupted canines and premolars. These new models should be clinically useful, providing highly accurate prediction.

Efficacy of "Dimodent" sex predictive equation assessed in an Indian population

Teeth are considered as a useful adjunct for sex assessment and may play an important role in constructing a post-mortem profile. The Dimodent method is based on the high degree of sex discrimination obtained with the mandibular canine and the high correlation coefficients between mandibular canine and lateral incisor mesiodistal (MD) and buccolingual (BL) dimensions. This has been evaluated in the French and Lebanese, but no study exists on its efficacy in Indians. Here, we have applied the 'Dimodent' equation on an Indian sample (100 males, 100 females; age range of 19-27yrs). Additionally, a population-specific Dimodent equation was derived using logistic regression analysis and applied to our sample. Also, the sex determination potential of MD and BL measurements of mandibular lateral incisors and canines, individually, was assessed. We found a poor sex assessment accuracy using the Dimodent equation of Fronty (34.5%) in our Indian sample, but the populationspecific Dimodent equation gave a better accuracy (72%).Thus, it appears that sexual dimorphism in teeth is population-specific; consequently the Dimodent equation has to be derived individually in different populations for use in sex assessment. The mesiodistal measurement of the mandibular canine alone gave a marginally higher accuracy (72.5%); therefore, we suggest the use of mandibular canines alone rather than the Dimodent method.

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.

Mandibular permanent first molar and incisor width as predictor of mandibular canine and premolar width

INTRODUCTION

Estimating the mesiodistal widths of unerupted permanent canines and premolars is an essential aspect of mixed dentition analysis. Several methods are used to predict tooth width. The best methods demonstrate high values of correlation and determination coefficients. In this study, we aimed to determine a linear regression equation that would predict the sum of the mesiodistal widths of mandibular permanent canines and premolars based on the sum of the widths of the 4 mandibular permanent incisors and first permanent molars.

METHODS

The sample consisted of 500 dental casts, obtained from white Brazilian patients (250 male, 250 female; average ages, 13.8 and 14.4 years, respectively). Mesiodistal tooth widths were measured with an electronic digital caliper. Intraclass correlation coefficients were used to determine measurement consistencies. Paired and unpaired Student t tests were used to determine right/left side and sex differences, respectively. A paired Student t test was also used to compare the predicted and actual sums of the mandibular permanent canines and premolars.

RESULTS

We found high values of correlation (r) and determination (r2) coefficients, varying from r = 0.795 to r = 0.81, and r2 = 0.599 to r2 = 0.656. These values are among the highest described in the literature for nonradiographic prediction methods. On average, there was no difference between predicted and actual widths of the mandibular permanent canines and premolars, and the standard errors of estimation were 1.49 mm for males, 1.36 mm for females, and 1.44 mm for the total sample (considering right and left sides of the mandibular arch together).

CONCLUSIONS

The proposed method showed good accuracy and was easy to use, but it must be tested in other populations.

Influence of sex and ethnic tooth-size differences on mixed-dentition space analysis

INTRODUCTION

Most mixed-dentition space analyses were developed by using subjects of northwestern European descent and unspecified sex. The purpose of this study was to determine the predictive accuracy of the Tanaka-Johnston analysis in white and black subjects in North Carolina.

METHODS

A total of 120 subjects (30 males and 30 females in each ethnic group) were recruited from clinics at the University of North Carolina School of Dentistry. Ethnicity was verified to 2 previous generations. All subjects were less than 21 years of age and had a full complement of permanent teeth. Digital calipers were used to measure the mesiodistal widths of all teeth on study models fabricated from alginate impressions. The predicted widths of the canines and the premolars in both arches were compared with the actual measured widths.

RESULTS

In the maxillary arch, there was a significant interaction of ethnicity and sex on the predictive accuracy of the Tanaka-Johnston analysis (P = .03, factorial ANOVA). The predictive accuracy was significantly overestimated in the white female group (P <.001, least square means). In the mandibular arch, there was no significant interaction between ethnicity and sex (P = .49).

CONCLUSIONS

The Tanaka-Johnston analysis significantly overestimated in females (P <.0001) and underestimated in blacks (P <.0001) (factorial ANOVA). Regression equations were developed to increase the predictive accuracy in both arches.

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.

Appraising number and clinical significance of regression equations to predict unerupted canines and premolars

A sound statistical or clinical reason for proposing several single linear regression equations (SLRE) for predicting unerupted canine and premolar tooth-width sums is needed. The purpose of this study was to develop a methodology to evaluate the number and the clinical significance of SLRE required. A 6-step methodology is presented that permits evaluating the number and the clinical significance of SLRE required for predicting unerupted canine and premolar tooth-width sums. It is important not only to evaluate the statistical need for specific SLRE in different populations, but also to state the clinical significance of their differences against commonly used SLRE.