Method:
Following routine screening, alginate impressions of 60 learners with good occlusion and 60 learners with crowding were taken and study casts made. Each group was divided into two equal groups of males and females. A vernier calliper was used to measure tooth sizes, arch lengths, and arch widths of each participant. Ten percent of the sample was re-measured at a later date by the researcher for intra- and by the supervisor for inter-examiner reliability. Data was entered, verified and analysed using the SAS 9.2 system. Descriptive statistics (mean, standard deviation, minimum and maximum) were calculated for tooth sizes, arch length and arch width. Paired t-tests were used to calculate group differences and p-values ≤ 0.05 were considered statistically significant.
Result:
Arch dimensions of crowded and non-crowded females differed significantly. In males however, the only significant difference of the arch dimensions between crowded and non-crowded individuals was in the mandibular inter-premolar region. The crowded individuals across gender showed significant difference in all but the mandibular inter-premolar arch dimension region. There was no significant difference in any of the arch dimensions between the non-crowded individuals across gender. The results of the mean tooth dimension in both gender groups shows that the non-crowded learners had significantly smaller teeth than those in the crowded group.
Conclusion: In this study, arch dimension plays a role in crowding only amongst females but not amongst males. Males with crowding had larger arch dimensions than females with crowding. Arch dimensions are similar in non-crowded arches across genders. Tooth size plays a role in crowding within and across genders