Correlation Of The Arch Form In Different Orthodontic Treatment Systems With Three Kinds Of Preformed Rectangular Nickel-titaniumarchwires

Introduction: The purpose of this paper was to correlate the normal arch formsof both maxillary and mandible with three kinds of commercially available preformedrectangular nickel-titanium archwires.Method:18AngleⅠ c lass normal occlusion were measured to get the ideal modelfor this research. Different preformed rectangular nickel-titanium archwire-bracketassemblies were used for the ideal model, and then we have experimental models. Theplanar graphs of ideal model and experimental models were taken by CANONEOS400D. Through the central incisors contact point build a spatial coordinates. Wecan get the Coordinate values of center of clinical crowns of each tooth in the spatialcoordinates. The mathematical beta function was used to derive planar projection ofideal model and experimental models’ arch forms. At last we can compare if theresome difference between the experimental arch form and the ideal arch form.Results: In the Edgewise system, the China Niti and the3M rectangularnickel-titanium archwire-bracket assemblies have almost the same result, they bothexceeded the intercanine width0.70mm in the mandibular arch, intermoler width0.01mm in the maxillary arch and1.00mm in the mandibular arch. The Ormcorectangular nickel-titanium archwire-bracket assemblies exceeded the intercanine width by2.20mm in the mandibular arch, intermoler width0.90mm in the maxillaryarch and1.60mm in the mandibular arch.In the Straight Arch Wire system the China Niti rectangular nickel-titaniumarchwire-bracket assemblies exceeded the intercanine width by0.50mm in themaxillary arch and2.20mm in the mandibular arch, intermoler width by0.90mm inthe maxillary arch and1.20mm in the mandibular arch. The3M rectangularnickel-titanium archwire-bracket assemblies exceeded the intercanine width by1.40mm in the maxillary arch and3.20mm in the mandibular arch, intermoler width by1.80mm in the maxillary arch and1.90mm in the mandibular arch. The Ormcorectangular nickel-titanium archwire-bracket assemblies exceeded the intercaninewidth by0.40mm in the maxillary arch and2.50mm in the mandibular arch,intermoler width by1.40mm in the maxillary arch and2.10mm in the mandibulararch.Conclusion: The three kinds of preformed rectangular nickel-titanium archwiresmight result in wider arch forms in both maxillary and mandible. The intercaninewidth difference is greater than the intermolar width. The mandible arch formdifference is greater than the maxillary. From these findings we can know thatdifferent nickel-titanium archwire have different influence to the final arch form, sochoose the right nickel-titanium archwire is important to the posttreatment retention,stability, and facial esthetics.