摘要The purpose of this study was to determine the total Bolton index (TBI) and anterior Bolton index (ABI), evaluate the clinical significance of tooth size discrepancies and the influence of gender variation of mesiodistal tooth width on Bolton Index and estimate which tooth has the greatest influence on Bolton Index. A total of 110 pairs of pretreatment dental study casts (41 male and 69female) were selected from patients treated in Department of Orthodontics of Union Hospital in Wuhan, China. A sliding dental Vernier caliper was used for the measurement of the mesiodistal tooth width. Descriptive statistical mean values, standard deviation, standard error of the mean values, coefficient of variance and the t-test were used for the statistical analysis of the data. The study found that TBI, ABI and the total sum of teeth width had no significant difference between male and female.Male group indicated that Bolton Index (BI) was mostly influenced by the width of lower right second premolar, whereas female group showed that BI was mostly influenced by the width of both the right and left maxillary lateral incisor.