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Extraction for orthodontic treatment is a common means. With modernmedical model from the simple the physiological and bio-based medical model topsycho - social medical model transformation, changing facial appearance ofpatients and their parents as the main reason for orthodontic treatment.Bimaxillary protrusion and upper jaw protrusion is a common malocclusion, themain clinical manifestations in patients with convex type, open lips lips grin andmaxillary incisors inclined so that patients are often urgent need to improvedental protrusion and face, which means that in the course of orthodontictreatment need as much as possible adduction incisors, reduced movement ofmaxillary molar extraction space occupied, thereby reducing the profile ofprotrusion. The traditional straight wire appliance required in most cases thewhole tooth movement, slow movement, anchorage control of the applianceduring the treatment of these key issues, the traditional method of strengtheningthe anchorage, including headgear bow, TPA bar, Nance arch, fixed lingual arch,etc., but in actual clinical work there is comfort, convenience, risk and patientswith sexual and other problems. The Tip-Edge plus differential in terms ofstraight wire appliance, without these cumbersome devices and anchorage controlstructure can achieve good treatment purposes.ObjectivObjective: In this study, cephalometric X-method evaluation of theTip-Edge plus differential straight wire and MBT straight wire appliance processof extraction spaces were closed position expensed against molar changes of thecharacteristics of two treatment systems and tooth movement in the treatment ofthe advantages, and further to provide theoretical guidance for clinicalorthodontics.Materials and Methods: The study selected malocclusion, maxillaryprotrusion and bimaxillary protrusion of the levels of the 10 cases, with Tip-Edgeplus differential straight wire appliance and the MBT straight wire appliance treatment, All patients are designed to remove the four on the premolar (upperjaw were removed the bilateral first premolar).Measured before and aftertreatment in patients with maxillary first molar sagittal，vertical distance and axialinclination, measured on cephalometric X-project statistical software applicationSPSS13.0 matching T of statistical analysis.ResultsResults: The maxillary first molar in the sagittal direction: TP group aftertreatment than before treatment and compared to its close in the PV line buccalcusp, near the contact points were moved forward a 1.30mm, 1.25mm,differences between the two groups statistically significant (P <0.05); MBTgroup after treatment and compared with that before treatment, compared to itsclose in the PV line buccal cusp, near the apex point, resistance center, near thecontact points are forward of 2.66mm, 2.59mm, 2.62mm, 2.6mm, differencesbetween the two groups was statistically significant (P <0.01). MBT group andTP group compared to the maxillary first molar relative to the PV line near thebuccal cusp of its near the apex point, resistance center, close to the amount ofcontact point moves forward more obvious, were moved forward a 2.89mm,2.80mm , 2.57mm, 2.83mm, differences between the two groups was statisticallysignificant (P<0.05). Vertical maxillary first molar: TP group, and after treatmentthan before treatment, compared with PP line near the tip of its point of resistancecenters are elongation of 0.43mm, 0.68mm. Difference between the two groupswas statistically significant (P <0.05).Conclusion：MBT straight wire correction of bimaxillary protrusion andmaxillary protrusion cases of tooth extraction process, the maxillary molarsmoved forward relatively large, relatively high anchorage loss, suggesting thatMBT straight wire appliance to be moderately suitable for occlusion or weakanchorage of the case, for strong anchorage in case of need for additionalanchorage devices. The application of Tip-Edge straight-wire technique ofdifferential treatment bimaxillary protrusion and maxillary protrusion extractioncases, not using any enhanced anchorage devices, maxillary molars moved forward a small amount of extraction space can be used within the maximumincome teeth, suggesting differential straight wire technique can provide stronganchorage requirements. Tip-Edge straight wire differential correction ofbimaxillary protrusion and maxillary protrusion cases the process of toothextraction, molar anchorage a certain degree of elongation, vertical anchoragecontrol to the poor, suggesting that the technology for high-angle should becareful in case.
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