Principles For Use Of The EdgewiseBracket With Rotation ArmsPAUL D. LEWIS, D.M.D.*Seattle, WashingtonThere has been little question a-mong those who are adept with theedgewise orthodontic bracket that it isone of the most efficient attachmentsyet designed for the correction ofmalocclusion of teeth. Technically itsscope is broad. It is possible to moveteeth in any direction with round andrectangular archwires when they areused in conjunction with the edge-wise bracket.There is, however, one weakness inthis mechanism as it has been used. Itis the difficulty encountered in thecorrection of rotated teeth. Slight orsevere tooth rotations are a problemto correct and, secondly, are a prob-lem to maintain in their new positionsafter the correction. Staples are gen-erally soldered or welded on themesial and distal of each band instrategic positions from second bicus-pid to second bicuspid for the purposeof applying leverage against thebracket for rotation movements. Lig-atures running through these staplesand ligated to the archwire slowly andgradually correct the rotation of theteeth after repeated activations.This procedure is generally slowand can be painful to the patient. Thetightening of the steel ligatures pass-ing through the staples and thentwisted tightly around the archwirefrequently causes sudden tension,blanching of the tissues, and pain.When threading ligatures throughstaples, it will often be found that thesteel ligatures are quite loose even be-fore the patient leaves the office. Thisseems to indicate that sometimes littlehas been accomplished by this methodin the correction of these rotatedteeth. Who has not forgotten to re-place rotation ligatures when retieingan archwire and then, at a later ap-pointment, find one or more teeth re-suming their one time rotated posi-tions? How often have you threadeda ligature and had the staple tearaway from the band?Many attempts have been made toovercome this weakness of the edge-wise bracket. The most successful itseems now is the combination of thebracket and two rotation arms ex-tending laterally from the bracketitself.When the archwire, round or rec-tangular, is seated in the brackets andthe teeth are in their relatively cor-rect positions in the dental arch, thearchwire rests not only in the bracketslots, but also on both edges of therotation arms. Thus, instead of one,there are three points of contact pos-sible with the archwire for each bandwith the application of a single lig-ature.In cases where there are severalseverelv rotated teeth, it is not al-Presented before the Pacific Northwest ways possible or advisable to fully seatComponent of The Angle Society of Ortho-dontia, Richland, Washington, September, a starting ''' archwire into each1958. bracket the first time (Fig. 1). The archwire may be ligated into most of* Clinical Associate, Department of Ortho-dontics, University of Washington. the brackets but only pulled close to182 July. I959Lewis I83while very efficient for rotated teeth,can be used as effectively on non-rotated teeth as well. Greater controlfor each tooth by virtue of the threepoints of contact with the archwiremeans increased stability. Each non-rotated tooth with its bracket and tworotation arms in contact with the arch-wire assists in the correction of adjoin-ing rotated teeth and their mainten-ance.Maintenance of corrected positionis especially necessary and importantin the case of the mandibular incisorswhen they are put under strain aswhen Class I1 elastic traction is beinaFig. 1or partially seated into others. Thearchwire generally rests against onlyone of the rotating arms on each ro-tated tooth and, when the steel liga-ture pulls the small round archwireinto the bracket, the prominent por-tion of the rotated tooth is gentlypushed into its correct positionthrough the spring and resiliency ofthe archwire acting on the prominentrotation arm. Thus a gentle pull andpush action starts the correction ofrotated teeth.In most cases after an appointmentor two it is possible for each tooth tohave the above mentioned three pointsof contact with the small round arch-wire.It is quite obvious that this makesthe use of staples unnecessary thuseliminating the time necessary for thesoldering of two on each band. Moreimportant, however, is the eliminationof the time consuming operation oftieing and retieing ligatures throughstaples on each rotated tooth. Simpleligature ties securing the archwire ineach bracket are all that is necessaryfor each tooth when rotation arms areused.ROTATIONThe bracket with rotation arms,-used. These incisors do not twist orturn during the time that elasticsare being worn, but are easily main-tained in straight alignment becauseof the constant three points of contactwith the rectangular archwire.It has always been good judgment touse small round starting archwires inmost of our cases after the bands havebeen cemented. It is a more physio-logic action in relationship to bothhard and soft tissues to get bracketengagement and start the levellingprocedure with these small roundwires, and is certainly less painful tothe patient. This is also ideal for thecorrection of rotations. Rotated teethrespond quickly and, in many in-stances, without pain or annoyance tothe patient when a little care is exer-cised in forming these starting arch-wires. Often the patient is not awarethat correction or rotations are beingaccomplished and, only when shownthe original casts, do they realize thechange that is taking place.It is easy to realize that the mostsuccessful corrections of rotated teethare those that are accomplished veryearly in treatment. When rotationarms are used and rotations are cor-rected, the once irregular teeth arenever allowed to return to their former 184 Brackets Vol. 29, No. 3malpositions in the dental arch. Thelonger the rotated tooth is maintainedin a corrected position, the less diffi-culty is encountered in its retention.Cases in which extreme rotationsmust be corrected havc always been ahazard to successful treatment and re-tcntion. Often these cases have provcna disappointment because such tecthproved mechanically difficult to rotatcand just as difficult to maintain duringand after treatment. A partial returnto their former positions scemecl al-most inevitable unless a constant vigilwas kept by always maintaining ten-sion on these teeth by ligaturesthrough staples. Rotated bicuspids andcuspids, as well as anferiors, fall intothis category and occur in one or botharches.Overrotation or, more accurately,overcorrection of rotated tecth hasbeen mentioned many times in thepast. but only now do we have a simpletcchnic and an efficient instrumentto actually and efficiently overcorrectthe once badly rotated tooth. With apair of pliers either rotation arm inaybe bent outward just enough fartherso that, when the light round archwireis drawn into the bracket by the liga-ture, the prominent rotation arm ispushed away from the archwire, thusactually overcorrecting the once ro-tated tooth.Whenever possible on the averagerotation, the bracket is placed ideallyin the middle third of the tooth mesio-distally. In cases of extreme rotationit may be impossible to use both ro-tation arms, in which casc one of themis cut off close to the bracket beforethe band is cemented. The remainingarm is bent out so it is a more prom-inent fulcrum when the bracket isligated; sometimes it will help to notchthe edge of the rotation arm slightlyto receive the round archwire. A spursoldered on the lingual oE the bandA$t.r CoiidionFig. 2 nhove, Fig. 3 below.from which a ligature can be appliedis very effective in the early stages ofcorrection, Fig. 2.On occasion, the rotation will beso extreme that. the archwire cannotbe ligated into the bracket for an ap-pointment or two and a ligature fromthe lingual spur to the archwire startsthe rotation with the notched arm act-ing as a fulcrum against the archwire.As soon as the bracket is available forligation, the lingual spur is no longernecessary. At a later appointment anew band with rotation arms may bemade and cemented.There are, in fact, instances inwhich no bracket at all can be usedat first, due to the extreme rotationof the tooth, Fig. 3. A plain band ismade with a lingual spur and anotched rotating arm to serve as a ful-crum. After the rotation is partiallycorrected through the action of theligature and the archwire on the ful- July, 1959Lewis185crum, the band is removed, a bracketideally placed, and the correction com-pleted. Fortunately these latter in-stances are not too common.PARALLEL ROOTSCertainly one of the most valuableassets of the bracket and, possibly, onethat is least understood, is the abilityto control the tipping of teeth. An in-dividual tooth or group of teeth canbe prevented from tipping by andthrough the use of spurs. Spurs stra-tegically soldered on the rotation armsprevent the undesirable tipping ofsome teeth during orthodontic move-ment and on other teeth can causedesirable tipping when needed.Canines and premolars in both jaws,but particularly in the mandible, oftentip undesirably during space closurein extraction cases. Who hasn't strug-gled with these teeth to maintain themin a somewhat upright position andfailed by several degrees to finish withparallel roots of the teeth on eitherside of the extraction spaces at theend of treatment.Just how important are parallelteeth and roots for our patients? Whatif lower canines do tip distally 6 de-grees, and second premolars tip for-ward a similar amount? Is this dan-gerous? Will they straighten up even-tually? If you are lucky, these mandi-bular teeth will straighten up by them-selves, but there most probably willbe a large open contact between thecanines and second premolars. Well,that is better, one might argue, than aslightly loose contact. That is true, butwhat about the resultant occlusionwhere large open contacts exist? If thcocclusion allows the canines and pre-molars to straighten up, is not one aptto complete treatment with premolarsand molars in an end to end relation-ship instead of the cusps in correctocclusion?Suppose we are unlucky and themandibular canines and premolars donot come out of their tipped positions?Periodontists tell us that the `"V" areacaused by the tipping of two teethcreates a food trap which ultimatelymay cause periodontal breakdown. Or-thodontically, too, tipped teeth in themandibular arch can easily lead toan increase of the curve of Spee anda return of a deep overbite.ANTI.TIP SPURSIn extraction cases anti-tip spurssoldered on the rotation arms of ca-nine bands gingivally to the archwireon the mesial, and occlusally on thedistal, prevent these teeth from tip-ping as they are being moved distally.Likewise, on the premolar bands,spurs soldered gingivally on the dis-tal and occlusally to the archwire onthe mesial, assist in keeping theseteeth from tipping in the closure ofspaces. Over the past ten years thishas been proven a countless numberof times with good results when thistechnic is followed.The technic for soldering onthese spurs is as follows: After theband has been formed and soldered,a small pellet of solder is fused on thesurfaces of both rotation arms neartheir terminal ends. A piece of roundor rectangular gold wire is soldered atright angles to each rotation arm atthe spots where the solder was pre-viously placed. The gold wires are cutoff and smoothed flush with the arch-wire, forming spurs, one gingivally,and the other occlusally, Fig. 4.There are several ways to solder onthese spurs; perhaps the easiest way isto ligate a short section of .022 x .028stainless steel wire snugly into thebracket. The spurs can then be sol-dered accurately onto the rotationarms and flush with the stainless steelsection. Spurs can be positioned, aftera little practice, almost as easily asstaples are soldered. I86 Brackets Vol. 29, No. 3-colmt*ANTI-TIP SPUR" PLACEMENTFig. 4 above, Fig. 5 below.Anti-tip spurs, as their name im-plies, when properly placed on thc ro-tation arms prevent the tipping of pre-molars and canines as they are beingmoved in extraction cases, Fig. 5.Mechanically the spurs greatly increasethe leverage action of the archwirethus enhancing the success of bodilymovement of these teeth. The rotationarms correct and/or prevent the unde-sirable rotations; the spurs soldered onthe arms act as brakes or controls asthe teeth are moved along the arch-wire. When the extraction space isclosed between the canine and pre-molar, the spurs continue to holdthese adjoining teeth in parallel posi-tions. At any time the spurs can beclipped off and smoothed down ifdesired.We all have cases, now and again, inwhich canines originally present distalaxial inclinations and second premo-lars, particularly the lowers, may alsoexhibit marked mesial axial inclina-tions, Fig. 6. The small round startingarchwires are very effective in correct-ing this undesirable tipping when anti-tip spurs are used as described. Thespurs vastly increase the leverage ac-tion of the starting round archwirein uprighting initially-tipped caninesand premolars. The application ofthese spurs is obviously not limitedto extraction cases alone.Spurs soldered on rotation armshave another function only men-tioned so far. It is the ability tostart or initiate the tipping of atooth or a group of teeth when andwhere desired. I refer to the normalartistic tipping or positioning ofmaxillary lateral incisors by meansof spurs, tip spurs in fact, solderedon the mesial rotation arms of thesetwo bands. Fig. 7. The spurs are us-ually soldered on the mesial arms sothat they are in contact with the rec-tangular archwire when it is seatedin the incisor brackets.Thus only very slight artistic bmdsFig. 6 above, Fig. 7 below. July, 1959 Lewis 187are necessary in the archwire to movethe central and lateral root apicesaway from each other. Generally,however, these bends are not needed.'The spurs on the lateral bands attimes are actually anti-tip in char-acter because they prevent the cen-tral and lateral crowns from tippingaway from each other and, at thesame time, stop their root apices lromtipping toward one another. It isstill a good idea to ligate these fourteeth together to prevent diastemasfrom occurring.These spurs are especially effec-tive in correcting perverted axial in-clinations of the maxillary ccnmlsand laterals. Often extreme tipping ofthese teeth presents quite a problcinin correction. The starting roundarchwires, acting on these spurs, in-itiate ideal or normal tipping ofmalinclined incisors early in treat-ment. Later, when a rectangular arch-wire is used, thc desirable tipping iscontinued. In some instances thesespurs can be used on lower incisorsas well.CONTROLLING ANTERIORAXIAL INCLINATIONDouble width brackets with two ro-tation arms for maxillary central in-cisors also are very effective on thesetwo upper teeth. Lingual root torque,so necessary for most maxillary cen-trals, is more easily accomplished withthe double width brackets, while tlierotation arms further add to the ef-ficiency of the bracket as has beendescribed.It was stated earlier that it is high-ly desirable in most cases to starttooth movement with light round re-silient archwires. Bracket engagement,leveling and first steps in the cor-rection of rotations are begun afterthe first archwire is placed. If possi-ble, all rotations are completed withthe .016, .018, or .020 round arch-Fig. 8.wires. Lest anyone think, however,that round archwires are overly fav-ored in the treatment of our cases,it should be stated clearly that rec-tangular archwires are used just asearly in treatment as is feasible in allcases. Greater control in every direc-tion is possible with the rectangularwire after rotations, bracket control,and initial leveling have been effect-ed.Maxillary six-year molars often ro-tate unfavorably and the correction ofthese rotations is essential to the nor-mal positioning of the maxillary buc-cal teeth during treatment and forsuccessful retention. This correction isquite easily accomplished through theuse of the double width molar brac-ket which has one rotation arm. Theterminal end of the rotation arm is afulcrum and, when the starting roundarchwire is ligated into the bracket,correction of the rotation is easily ac-complished. The mesiobuccal cuspis pulled bucally and the distobuccalcusp pushed lingually, Fig. 8. Whenthe correction is completed, the molarcan never rotate adversely as long asthe bracket is ligated to the archwire.Another important feature of therotation arms should be mentioned.It has to do with the temporary re-duction or bending away of one armon the prominent edge of a rotatedtooth so that a starting archwire willnot be too prominent on extremely ro-tated maxillary incisors when ligated.This bending away of the rotationarm is done at the time the startinground archwire is first placed and 188 BracketsVol. 29, No. 3makes bracket engagement much sim-pler at this first appointment. Afterinitial tooth movement has takenplace, the rotation arm is graduallybent out again. The ability to reduceor increase the prominence of eitherrotation arm further increases the use,flexibility and the efficiency of thisbracket.643 Stimson Bldq.The AngleOrthodontistA magazine establishedby the co-wor/pmof Edward H. Angle,in his memory . . .Editor: Arthur B. Lewis.Business Manager: Silas J. Kloehn.Associate Editors: Allan C. Brodie,Morse R. Newcomb, Harold J. Noyes,Robert H. W. Strang, Wendell L. Wylie.Vol. XXIX, No. 3 July, 1959