Ambreen Afzal, Syed Shahbaz, Mahmood Haider.
Estimation of perpendicular distance from cuspids and Prefabricated Arch Wires in arches of patients.
J Surg Pak Jan ;12(1):13-5.

Objective: To estimate the perpendicular distance from cuspids and prefabricated arch wires in arches of patients using 3M MBT arch wire system. Study Design: Cross-sectional analytical Place of study: Orthodontic department, Karachi Medical & Dental College. This study was of six months duration. Patients & Methods: Sampling technique was non-probable, purposive. Inclusion criteria was patients not orthodontically treated, having symmetric arches of adult dentition. Inter-molar width was described as cross arch distance between the mesiobuccal cusp tip points of the right and left 1st molars in millimeters while inter-canine width was cross arch distance between the buccal cusp tip points of the right and left cuspids in millimeters. After taking consent from the patient, impressions of the maxillary and mandibular arches was taken with alginate. Ortho plaster was used for making the cast. Occlusal surface of the casts were scanned, with a ruler included for magnification error using HP scanner version 1200. Using Photoshop software program version 7(Adobe System), the proximal contact between the two central incisors was used as the origin of the X and Y coordinate. The landmarks were joined starting from one molar and ending on the other. This gave the arch form of the patient`s arch. The wires were superimposed on the scanned images maintaining the x and y coordinates. While each wire superimposed on the image touching at maximum number of teeth, the perpendicular distance between the canine cusp tip and the wire in horizontal axis was measured. The values obtained from both the sides are summed up and termed as difference in inter-canine width. All the three arch wires, that is, orthoform I, orthoform II and orthoform III were superimposed on the patients` arches. Results: Two hundred patients were included in our study out of which females were 138. All the three types of wires in maxillary arch, the Orthoform I wire, which is the tapered type showed the least mean value (1.99) with a S.D of 3.23. In the mandibular arch, the mean value for Orthoform I was calculated to be least (.63) with S.D of 2.12. However, the value for Orthform III (.65) with S.D of 2.37 showed very little difference than Orthoform I. All the three types of arch wires used in this study affect the inter-canine distance. Conclusions: The current preformed NiTi wires are too wide for many patients and should be modified when these patients are being treated.

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