Dental Crowding and Its Relationship to Tooth Size and Arch Dimensions

Tooth size arch length discrepancy (TSALD) is a well defined means of assessing dental crowding. In previous literature conflicting evidence exists regarding the part played by tooth size and arch dimension in causing dental crowding. The objective of present study were to; examine the relationship between tooth size and arch dimension in crowded and non crowded arches, and to find out the major contributing factor in dental crowding of each. Eighty patients, 20 males and 20 female in crowded and non crowded group comprising of 40 patients each, with an age range of 14-18 years, reporting to outdoor of orthodontic department, was selected. All subject met the following criteria; 1) No cast with missing or impacted teeth. 2) No history of previous orthodontic treatment, 3) No cast showing any dental anomalies. The study included on clinical examination, crowding was assessed clinically in crowded arches with gross mal-alignment of teeth and non crowded arches showing no or mild crowding. Arch dimensions was measured from left to right First permanent molar at the intersection point of lingual groove with gingival margin on the dental cast and tooth size measurement were taken from the anatomatical contact points with the help of Vernier caliper. Similarly inter premolar width was measured. Inter canine width was recorded from canine tips. Arch length was taken with the help of Brass wire directly from the dental cast following the curve of occlusion from mesial marginal ridge of first permanent molar. Data was analyzed by using SPSS (version 10) in personal computer. Paired and independent ttest was used to find out the group differences in crowded and non crowded arches. Results showed that overall no significant differences (p>0.05) were found in tooth size between the non crowded and crowded arches, regardless of whether the tooth size was compared individually or collectively. Statistically significant differences (p<0.05) were observed when arch dimension of crowded and non crowded groups were measured particularly lingual arch width at the inter molar and inter premolar area. No statistically differences were found between the males and females comparison except that female showed smaller values as compared to males in every aspect of measurement.