Relationship among Intercanine Width, Intermolar Width and Arch Length in Upper and Lower Arches

Intercanine width, intermolar width and arch length are essential for diagnosis and treatment planning and are closely related factors in orthodontics.The purpose of this study was to determine the correlation between these measurements and how these measurements are related to each other. Dental casts of 100 orthodontic patients (72 females and 28 males) with a mean age of 18.7 years (12-38 years) in the permanent dentition attending the orthodontic department of the University of Lahore, Lahore, Pakistan were randomly selected. The casts were photocopied 1/1 with maximum contrast. Measurements were made on the photocopies of the upper and lower dental casts. Correlation between variables was determined using spearman’s rho correlation coefficient. The data showed very high correlation between intercanine width and intermolar width of both upper and lower arches and a weak correlation was observed between upper intercanine width and upper arch length as well as lower arch length. Correlation was significant between upper and lower arch lengths.