Comparison of preformed orthodontic archwires with modified dental arch forms: A cross-sectional study

BACKGROUND: Selecting an archwire that respects a patient's native arch form is central to stability and periodontal safety. This study quantified Yemeni adult dental arch dimensions and predominant arch forms and compared them with commonly used preformed nickel-titanium (NiTi) archwires using a bracket‑point-based reference graph. METHODS: In this cross‑sectional analysis, pretreatment casts from 222 subjects (Angle Class I and II; 16-28 years) were digitized. Clinical bracket points defined transverse widths (intercanine, Wc; intermolar, Wm) and depths (Dc, Dm). Arch form was categorized as tapered, ovoid, or square. Twenty‑seven 0.019 × 0.025‑inch preformed rectangular NiTi archwires were traced on a reference grid incorporating bracket‑base offsets, and widths at the canine (L3) and first‑molar (L6) levels were compared with sample means. Repeatability was assessed on a subsample. RESULTS: Ovoid was the predominant arch form. Males exhibited larger transverse dimensions than females. Across brands, most preformed NiTi archwires were wider than natural arches at the canine level. Mean (archwire-arch) differences were + 3.38 mm at maxillary canines and + 1.94 mm at maxillary first molars; in the mandible, + 4.05 mm at canines and + 1.53 mm at first molars. CONCLUSIONS: No single preformed archwire matched the Yemeni adult sample across arches and landmarks. Clinical selection should prioritize archwires that approximate the patient's pretreatment form, with individualized adjustments where indicated.