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ePaper created 2018-02-22, 14:08:19 | version 1.38.0
◊Page3 Dental Tribune Middle East & Africa Edition | 5/2016 ORTHO tribune 4 BSAT, we are able to obtain more control over dental movements and significant changes in facial profiles, thereby enabling the treatment of cases of critical anchorage without theneedforpatientcooperation. In the case of patient L.S.C.O., the first alternative plan presented, but not accepted, was treatment with orthognathic surgery. The treat- ment option chosen included the extraction of four premolars. For the extractions to have the expected success and promote the necessary and desired aesthetic and functional alterations, we planned to use the Segmented Arch Technique, Mar- cottetypeAmechanics. These mechanics maximize the re- traction of the anterior teeth with minimum loss of anchorage and therefore ensures maximum retrac- tionoftheincisorsandlips. We mounted maxillary and inferior braces with straight-wire brackets with prescription Orthos (Ormco Corp, slot 0.022” x 0.028”). The first phase of the treatment consisted of the closure of generalized diaste- mas with elastic power chains. The severe biprotrusion, associated with hygienic deficiency, resulted in large gingival hyperplasia, which made it necessary to perform a primary gin- givectomy surgery so that we could continuetheorthodontictreatment. Extractions of the first four premo- lars were performed together with traction on the left maxillary canine, including using a cantilever made with a TMA wire (0.017” x 0.025”) to apply a light and continuous force. Thistoothprotrudednexttothesec- ond premolar because it was includ- ed in the posterior segment of the arch. At this stage of the treatment, we considered it necessary to carry outasecondgingivoplasty. The type T handles (used in maxi- mum, critical anchorage cases) were constructed with a TMA wire (0.017” x0.025”)toclosetheextractionspac- es that were 14.14 mm and 11 mm on the right and left maxillary quad- rants, respectively. As a strategy, we used the moment/force (M/F) dif- ferential ratio on the anterior (á) and posterior (â) segments to align by segments. The extraction spaces were closed with a controlled tilt of the anterior segment with the center of rotation on the apical region of this group of teeth. Note the controlled tilt of the anterior segment with changes of the occlusal plane as seen in the type A mechanics of TAS when the handles are used as suggested by Marcotte. The pre-activation of 45º in the back of this handle generates an intrusive vertical force that, when applied to a point in the front of the center of resistance (CRes) of the an- terior segment, generates a moment of intrusive force that is favorable by raisingtheM/Fbyapproximately7/1 (the ideal ratio to obtain movement ofcontrolledtilt). At the completion of the closure of the extraction spaces, to verticalize the anterior segment, we used Ianni type I radial correction handles, which have been biomechanically tested in laboratory and tested clini- cally by the author. These handles, when pre-activated correctly, can developanysystemofdiverseforces necessary for the various mechanics of radial correction and verticaliza- tion of segments (verticalization with extraction or intrusion and ver- ticalization while closing or opening the extraction space). At the end of this phase of treatment, we initiated a completion stage with the use of continuousarches. Results The final occlusion was very satisfac- tory with the molars and canines at Angle class I and the correction of the biprotrusion and the anterior openbite. The facial aesthetic improved con- siderably, which raised the self-es- teem of the patient who, according tohim,learnedandstartedtosmile. In the new facial appearance, we can see a substantial reduction of the lip protrusion that is compatible and similartotheresultsoforthognathic surgery. Phonoaudiologic exercises promoted the improvement in the perioral chin muscle tone and re- trained the breathing and swallow- ingfunctions. The superimposition of the cepha- lometric tracings confirms the ex- tensive reduction in the inclination and protrusion of the incisors and the alterations in the bone and skin profile.Thepatientreportedpositive psychological changes due to the aestheticfacialimprovement. This clinical case confirms that the Segmented Arch Technique, sug- gested by Burstone at the end of the 1960s, allows for effective control of the anchorage without the need for any cooperation on the part of the patient. Differential M/F ratios used on the anterior and posterior segments allowed for a large retrac- tion of the anterior teeth, thereby reaching the treatment objectives: significant improvement of the fa- cial profile, and aesthetic and func- tional occlusion. Therefore, the use of TAS type A handles is an excellent mechanical option in orthodontic treatment with extractions when maximal retraction of the anterior segment is desired to promote ex- tensive and important changes in thetegumentalprofile. “Inmostcases,asuccessful orthodontictreatment dependsoncarefulplanning oftheanchorage“ DrIanniFilho Assistant Professorin Orthodonticsat the “Araraquara”Dental Schoolof theSaoPaolo StateUniversity–Brazil andAuthorofOpenBite -achallenge