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Abstract

Background: Maintaining the pre-treatment mandibular inter-canine dimension is crucial for stable post-treatment retention as minor changes can increase post-treatment relapse. This study aimed to identify changes in mandibular inter-canine width caused by active orthodontic treatment using tapered preformed NiTi mandibular arch-wires and predict future stability proportionally. Methods: A 6 months’ study at School of Dentistry Islamabad involved 60 patients with tapered mandibular arch forms, fully erupted, non-anomalous, and permanent mandibular canines. The patients underwent non-extraction fixed orthodontic mechanical therapy treatment using conventional pre-adjusted edgewise brackets. The study involved detailed clinical examination, orthodontic study casts, orthopantomograms, and lateral cephalograms. The initial pre-treatment mandibular inter-canine width was recorded using digital vernier caliper. After levelling and alignment, the mandibular cast impressions were repeated, and mid-treatment inter-canine width was calculated. Results: Statistically significant differences were found between pre-treatment and post-treatment widths. The mean pre-treatment width was 26.81 mm, while the mid-treatment width increased to 27.26 mm after levelling and alignment. Statistically significant differences (p=0.001) were found between pre-treatment mandibular inter-canine width (T1) to during treatment mandibular inter-canine width when considering gender. When considering age-wise analysis, there were no statistically significant differences between pre-treatment mandibular inter-canine width (T1) to during treatment mandibular inter-canine width. Conclusion: The commercially available preformed tapered NiTi arch-wires alter the original mandibular inter-canine width in patients which have a natural tapered mandibular arch-form, increasing the risk of relapse, hence predicting future long-term instability.
Pak J Physiol 2025;21(3):46–9, DOI: https://doi.org/10.69656/pjp.v21i3.1872