Dental Arch Width Dimensions among Pre-treatment Orthodontic Patients In A Nigerian Tertiary Hospital

Abstract

Background: Accurate assessment of dental arch width is essential for orthodontic diagnosis and treatment planning, as it
influences space availability, occlusal relationships, aesthetics, and long-term stability. Arch width varies by gender, age,
ethnicity, and arch form, yet most normative data are derived from non-African populations, limiting their applicability in
African clinical settings. This study aimed to determine maxillary and mandibular arch width dimensions among pre-
treatment orthodontic patients attending a Nigerian tertiary hospital.
Methods: This descriptive cross-sectional study was conducted at the Orthodontic Clinic of the University of Benin
Teaching Hospital. Pre-treatment maxillary and mandibular dental casts of 150 orthodontic patients were analysed.
Intercanine and intermolar arch widths were measured using a calibrated digital caliper. Data was analysed using SPSS
version 27. Descriptive statistics were computed, and comparisons were made by sex, age group, and anterior arch form,
with statistical significance set at p < 0.05.
Results: The mean age of participants was 17.92 ± 9.05 years, with females constituting 62.3% of the sample. Males
demonstrated higher mean values for all arch width parameters. A statistically significant difference was observed in
maxillary intercanine width, which was greater in males than females (p = 0.041). No significant age-related differences
were found in any arch width parameter. Casts with anterior spacing exhibited significantly greater maxillary (p = 0.007) and
mandibular (p = 0.003) intermolar widths, while crowded arches demonstrated reduced posterior arch widths.
Conclusion: Dental arch width among pre-treatment orthodontic patients varies significantly by sex and anterior arch form
but not by age. Posterior arch width plays a key role in the presence of spacing and crowding. These findings highlight the
importance of population-specific arch width assessment to support accurate, evidence-based orthodontic treatment
planning in African populations.
Keywords: Dental arch width; Orthodontic patients; Pre-treatment asses; Tertiary health facility