Mixed dentition space analysis among Nepalese Brahmins/Chhetris

Abstract

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

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

“…2 The aim of our study was to check the reliability of Moyer's and Tanaka -Jhonston methods when applied to Nepalese population. As previously reported by Gyawali et al 8 , for power=0.8 and significance level 0.05, sample size of ≈ 90 is required .In our study, we measured the mesio-distal tooth size of seventy seven subjects and difference between predicted and actual mesiodistal tooth size was analyzed. In our study crowding was not used as exclusion criteria.…”

“…This may be due to difference in sample selection method. Gyawali et al 8 have used only Bahun and Kshetri caste group samples where as in present study and study by Jaiswal et al 9 have not used caste as exclusion criteria. Tanaka-Johnston analysis overestimate the mesio-distal size in both maxilla and mandible for males and females.…”

“…Previous studies done in Nepalese population present similar findings. 8,9 In study done 8 Moyer's prediction at 75% overestimated the mesio-distal size in maxilla and mandible in males; and mandible in females. Jaiswal et 9 al didn't compare actual value with Moyer's prediction at 75% because they found that Moyer's prediction at 50% itself overestimated the mesio-distal size in Nepalese subjects.…”

“…Moyer's analysis at 50% overestimated mesio-distal size in males but the difference was not significant statistically however in females statistically significant underestimation of mesio-distal size was seen when Moyer's prediction at 50% was used. Gyawai et al 8 have reported that Moyer's 50% underestimated the tooth size in both males and females while Jaiswal et al 9 have reported the opposite. This may be due to difference in sample selection method.…”

“…[4][5][6][7] Results of previous studies done in Nepalese population show that both these methods have questionable accuracy when applied to Nepalese population groups. 8,9 The aims and objectives of this study were to test the reliability of Moyer's and Tanaka Johnston mixed dentition analysis in Nepalese population, to construct prediction tables for Nepalese population if these methods were found not reliable.…”