A Case report of Class II Division 2 Malocclusion in Adult women treated by Fixed appliance with CIA and removable anchor plate incorporated bite plane: Biomechanical Considerations

Abstract

This article describes our treatment of Class II, division 2 adult patients requiring premolar extractions. Division 2 cases are often characterized by severe deep bites, lingually inclined upper central and lower incisors, and labially flared maxillary lateral incisors. This patients also tend to exhibit problems with the upper and lower occlusal planes, such as deep curves of Spee, High lip line, marked labiomental depression. Because of the deep bite and supra eruption of the maxillary incisors, the gingival margins of the maxillary anterior teeth are malaligned, and the lingually inclined mandibular incisors have excessively high gingival margins ( Fig. 1 ). The treatment protocol for this patients includes extraction of premolars both upper and lower in right side to relieve crowding, with simultaneous correction of the deep bite by intrusion of the upper and/or lower incisors. Intrusion mechanics are performed with a bite opening bend on a preformed nickel titanium arch wire. Space closure is accomplished with power chain and guard behind the extracted site in anchor plate. Extraction of upper premolar and lower 1st molar (tooth no 36) in left side was done earlier. A 21 years old women with Cl-II Div-II malocclusion type B came to Dental Centre, Dhaka, with chief complaint of an unhappy smile. Retroclined 4 Incisors, Deep bite, Crowding, deficient lower facial height, Gummy smile and a moderately convex hard- and soft-tissue profile because of a retrusive mandible with over jet of 1.5mm and over bite of 6 mm was observed. The mechanics plan should be individualized based on the specific treatment goals. Camouflage Treatment was done with the help of an anchor plate incorporated anterior incline plane. Intrusion mechanics are performed with preformed nickel titanium Connecticut Intrusion Arch (CIA) and anchor plate incorporated bite plane. Treatment was successfully completed with extractions of both pre-molars in right side and left lower 1st molar (Tooth no 36) and upper 1st premolar(Tooth no 24) already extracted ( Fig. 2 A) before starting of orthodontic treatment. Treatment of 20 months which improves incisor inclination, Deep bite correction; eliminate crowding, normal smile line and improvement of gummy smile. With the above mentioned protocol normal inclination of both upper-lower incisor, normal over jet and over bite were also achieved. DOI: http://dx.doi.org/10.3329/bjodfo.v1i2.15987 Ban J Orthod & Dentofac Orthop, April 2011; Vol-1, No.2, 18-24

Von Mises stresses on Mushroom-loop archwires for incisor retraction: a numerical study

“…ML archwires with CNA Beta III wire material (0.017 x 0.025-in) are very important appliances to retract anterior teeth with torque and anchorage control. 7 , 9 - 12 Closing loops incorporated in archwires helps to control anterior torque over incisors during retraction, but they should work in an elastic range to develop a desired force system. Besides spring geometry, properties as low load deflection rates, adequate spring gradient (spring rate) and working range should be considered in closing loops.…”

“…CNA Beta III alloys are nickel-free, and prevents allergies in some patients, have a good range and are about 42% less stiff than stainless steel. 23 Many papers show case reports 8 - 12 dealing with CNA Beta III alloys, but no study demonstrates experimentally or numerically what occurs in the loop body with Mushroom geometry neither their force system after activation. In simulations, the results represent the behavior of the same object that is based on its theoretical model, so there is no variation in the material behavior.…”

“…If molars move mesially, the extraction spaces may be lost and dental protrusion may not be perfectly corrected. [7][8][9][10][11][12] No study at this time verified the tension levels on Mushroom archwires geometry, but only clinical studies were performed showing good results. 7,9 Thus, the present study aims to study using FEM the von Mises stresses over a 3-D Mushroom loop design after activation.…”

“…If molars move mesially, the extraction spaces may be lost and dental protrusion may not be perfectly corrected. 7 - 12 …”