1. CD # 1

2. Introduction. In order to overcome the limitation of free teeth movement which was restricted by the Edgewise Arch Technique, Dr. Begg started to use round rather than rectangular arch wires with edgewise bracket slot. Using round archwire with traditional (Zero toque, Zero tip) edgewise slot, plus a combination of wire and elastic tension made this segmental teeth movement technique able to permit a group of teeth to move properly. Careful analysis of these force components will lead this group of teeth into the desired treatment objectives.

3. The Edgewise Arch Technique was formally introduced into the profession in 1929 by Dr. Angle. After he had advocated the pretreatment removal of teeth in selected cases in 1907, he emphasized the importance of permitting teeth to tip freely by excessive force generated by screw mechanism (Figure 1).

4. When he said all teeth should be retained, he designed the Edgewise arch Technique which provide an excellent control Labiolingual, vertical, and misiodistal movements. Both P.R. Beeg of Adelaide, South Australia and C.H. Tweed of Tucson Arizona who had been trained by Angle, realized that relapse often followed expansion along with a desire to improve soft tissue profile. So they both began to routinely remove teeth or reduce tooth width by misiodistal stripping in patients with excess teeth substance. However, Tweed continued with Edgewise Mechanism and in order to overcome the limitation of free tooth movement, he increased both elastic and arch wire forces and used extraoral anchorage to help direct the teeth. Dr. Begg Began to realize that the Edgewise Mechanism was not designed to facilitate the closing of extraction spaces

5. or reduction of deep overbites, and this technique was an expansion none extraction one. So he started using 020" round platinized gold rather than rectangular archwire (Figure 2). When he later switched to use 018" round rustles steel wire with vertical loop and intermaxillary hooks, he encountered an undesired root moving forces, prolonged anterior bite opening, and lose of intraoral anchorage.

6. Before he developed his technique and philosophy, Dr. Begg decided to use Ribbon arch brackets which allowed the teeth to move under much lighter forces, because of its narrower bracket and its vertically facing slots (Figure 3). He also used round "Rustles Steel" wires. However, it was either too brittle or too soft.

7. Subsequent refinements of the edgewise appliances such as wider Siamese brackets and preangulated bracket slots had failed to accomplish the major repositioning of teeth and jaws, because straight wire mechanism using rectangular archwire is not able to achieve tipping and upriting rather it restricted bodily teeth movement. This modified edgewise technique is able to accomplish both teeth and jaws repositioning with a good ability to open the deep bite by intruding upper and lower anterior segments without an urgent need for extraoral forces, or confrontation with the need to preserve or administer the space left by such extraction. The preparation of anchorage which was indicated by Tweed is automatically accomplished in this technique. In contrast to the straight wire mechanism widely used today, Round Edge Orthodontic technique differs from the traditional methodology by the ability to apply combination of different forces to get a result force able to reposition the jaws and teeth segments.

8. Twin-edge bracket used in the technique Twin edge bracket of 022" manufactured by TP. Orthodontics, INC. used in this technique has many advantages including vertical slot with rounded corner for easy insertion of auxiliaries when treatment objectives are require them (Figure 4).This vertical slot is also used to engage the NiTi Wire in severe crowding cases. The flat or curved bases are carefully adapted to the labial and buccal contours of the teeth. Bracket features include smooth rounded corners and a low profile for patient's confront. The parallel tie wings on curved brackets assure you of proper rotational control. It is a Zero degree torque, Zero degree tip rectangular slot of (.022”-.032”).

9. BRACKET WIDTHS Modified Edgewise Brackets size and Bases. (FIGURE 5)

10. INTRODUCTION TO ROUNDEDGE MECHANISM. All Orthodontic techniques require three mechanical components: 1. Something to attach to a tooth-the bracket. 2. Something on which the tooth-bracket will slide or tip in a pre- determined direction-a mono-rail or archwire. 3. Something to move the tooth-bracket along the archwire at various speed-a force component composed of various combinations of elastics and wire’s tension. Most orthodontic problems can be solved by applying the above components in combination so that, hopefully, the desired results will be accomplished. Difficulty rose when we attempt to apply the force component to living dentition. Controlled tooth movement depends heavily on proper evaluation and manipulation of the entire power system.

11. In the analysis of the force components, one must consider two essential engineering principles: 1. Forces must be analyzed in straight line vectors. 2. All forces must be seen as acting reciprocally. But in Orthodontics, we are working in a three dimensional system with force vectors in three planes-horizontal, vertical, and sagital. Therein hangs our problem! In an overall view of Roundedge Appliance, we see that most resultant forces are negative or even potentially destructive. Since we employ heavy forces to accomplish rapid tooth movement, careful analyses and meticulous control is necessary to avoid undesired teeth movement. Force components Analysis

12. A brief evaluation of so called class II Division 1 1 st Bicuspids Extraction case Inter-maxillary force system using elastics might be helpful in clarifying the potential force problems. Typically, the objectives in this case are: 1. Distalization of the Maxillary Anterior segment to good esthetics. 2. Maintenance of Maxillary Posterior segment. 3. Inviolate maintenance of Mandibular Anterior segment. 4. Mesial shift of the Mandibular Posterior segment to good function. 5. Correction of excessive overbite. Classically, these objectives are accomplished by use of class II inter- arch elastics traversing from the mandibular posterior to the maxillary anterior segments. The elastic acts equally to distalize the maxillary anterior segment and move the mandibular posterior segment forward.

13. When we reduce the force involved into straight line vectors, our treatment objectives are being accomplished in horizontal plane. However, in the vertical plane we face the undesired teeth movement. The vertical component of Class II elastic force is extruding the maxillary anterior and mandibular posterior teeth to the point of extraction (Figure 5).

14. These destructive and negative force components could be neutralized by the act of the archwire tensions like Rocking chair and High pull headgear in the upper, and gable bent or reverse curve in the lower arch. Proper calculation of these force components will lead into resultant forces, which would move the teeth segments toward the treatment objectives (Figure 6).

15. Segmental Teeth Movement The Round Edge Orthodontic technique is designed to permit group of teeth to move in the jaws under the influence of resultant forces-as would occur naturally in the presence of attrition. However the posterior segments (molars and premolars) naturally move mesially throughout the life by attritional occlusion. The anterior segment teeth should move distally by application of proper resultant forces generated by this mechanism. The original edgewise mechanism designed by Angle was "expansion none extraction technique" because of the limitations of free movement inherent in edgewise slot engaged to the same dimension- rectangular archwire. Dr. Begg when first used 020" platinized gold round wire rather than a rectangular one to allow the teeth to move freely under light force, encountered the undesired root moving forces only because he did not reduce the force involved into straight line vectors. The vertical components are actually responsible for the undesired movement as well as prolonged anterior bite opening, and lose of intraoral anchorage (Figure 5-6). The proper and careful analysis of the force component generated in this technique, plus the fact that posterior teeth are not moved distally, precludes the use of distally directed extraoral forces (molar headgear). However, high-pull or vertical extraoral force is really required when the

16. proper combination of archwire and elastic forces is used to open the anterior overbites. 022" Twinedge brackets used in the technique with 020" round archwire with proper application of Rocking Chair curve and Reverse curve or Gable bent ensure maximum control of the vertical dimension. Using.022” edgewise bracket slot with.020 round wire create.002” Bracket-Wire friction or 9 degree tipping ability. This minor tipping movement is generated during retraction of anterior segments, or closing of extraction spaces. The appliance is designed to permit the teeth segments to move toward the desired final positions; this movement is bodily type with Minor tipping characteristics. The segmental teeth movement is controlled by the operator and may require heavy forces; when properly analyzed will lead to the desired treatment objectives.

17. Misconceptions Segmental teeth movement in this technique is not dependent on the removal of teeth. It is not an extraction technique. Excellent result can be achieved in selected cases when treated nonextraction. And this technique is able to reposition teeth and jaws as it happened in functional appliance treatment. Teeth volume, mesial distal dimension is of primary importance, not teeth count. And it is also important to accept loss of tooth structure to correct errors in tooth volume. Teeth are suppose to wear anthropologically but that does not happened in modern men. Our approach in this technique paramount to Begg attritional Occlusion.

18. Three-Tooth Concept Groups of teeth: Segmental Teeth Movement Technique has three segments considered from volume aspect rather than number standpoint and these are: ONE Anterior Segment involved usually six teeth centrals, laterals and cuspids. Our prime concern here is volume of this segment, the arrangement of these teeth in the segment, and how does the tooth occupy its portion of horizontal freeway space, such as protrusive, crowded or inclined. Two Posterior Segments left and right involved molars and premolars in each side. Our prime concern here is the availability of spaces for correction of malocclusion, and to allow anterior correction first to establish class I Angle relationships. Limits of movement The limits of our orthodontics correction are defined by a "DENTAL BOX" as the only area in each we can work as limited by muscles and skeletal and Esthetical considerations. 1. Posterior limit: Our prime concern here is to limit 1st molar distalization to the exact diagnostic original position. 2. Anterior limit: Our prime concern is that the lower anterior teeth to be place anteroposteriorly

19. In a zone for the best functional and esthetical result for the given case In (Figure 6-c). The Anterior Limit shoud be on Line 1 Or The AP Line in orthodontic patients who belong to one racial category “Caucasian”.

20. When treating different racial group, this measurement should have its variation according facial type and pattern in this race. During the course of my clinical orthodontic practice in Port-Au-Prince, Haiti, and working on a variety of different patients especially the Haitian Black Caribbean orthodontic patients, I developed the desire of accepting a different antero-posterio norm of the lower incisor position to the AP line. From +5mm to +12mm of the lower incisor to the AP line, I was able to finish my orthodontic treatment with well and harmonious balanced faces. In( Figure 6-d ) the Anterior limit could be forward to AP line + 6 mm

21. In( Figure 6-e) the Anterior limit could be forward to AP line + 14 mm and stile esthetically Exactable So the proper Position of the lower anterior teeth depend on our proper evaluation of every individual case. It is extremely important to make your decision on where the lower anterior teeth should be place

22. DIAGNOSIS The diagnosis usually centers around making the decision to extract or not. Although this decision should be based on the severity of the malocclusion, treatment goal ability of the operator, age of the patient, condition of the teeth, patient's cooperation, skeletal pattern and patient's preferences, we should also consider our limits of movements to be inside the previously defined dental box. The segmental teeth movement technique is capable of treating the most severe malocclusions with or without extraction of teeth. Therefore, the decision on extraction should be made based on the individual need of each patient, not on the limitation of the technique. Usually there is no need to extract to correct class II or class III malocclusion in a growing individual, unless teeth removal is needed to balance the discrepancy between arch length and teeth mass. There is no limitation on which and how many teeth is needed to be removed in this technique. Mesiodistal reduction of proximal enamel of posterior teeth may be indicated in border line cases. Treatment plan should permit the natural mesial teeth movement created by attritional occlusion, not retard or attempt to reverse it. Cephalometric analysis with combination of models, photographic and panographic analysis is important in order to make proper diagnosis.

23. based on this and Orthodontics Diagnostic Puzzle Developed By Manhal Yazji DDS IBO the decision to determine the need to reduce tooth substance is easier and clearer Cephalometric Facial Model

24. APPLIANCES Twin edge brackets of 022" edgewise slot slide on a 020" round archwire is the proper tool of segmental teeth movement mechanism. This bracket in conjunction with 016” or 020” round NiTi wire, allows the rapid initial movement of teeth including rotation, leveling and proper axial inclination. Sectional archwire in severe crowding cases also allows anterior alignment during the first two or three months of treatment. When extraction is indicated for treatment of anterior crowding and protrusion, we routinely align the anterior teeth first, this enables us to place and cement bands in stages which is easier on patients, giving time allowance for healing of extraction spaces. During this period we are also able to unite the anterior teeth as one segment free of rotations and malalignement. Whether we are using sectional or NiTi archwire if brackets placement and wire plan are correct, teeth will slide freely throughout the edgewise bracket slots.

25. Using sectional wire has dramatically decrease after the NiTi arch wire was available. When performed 020" NiTi wires are engaged and securely fastened into the 022" edgewise bracket slots, rotation, leveling, and proper axial inclination are automatically accomplished. In (Figure 7B), 016” NiTi wires are used to initiate teeth movement in severely crowded cases.

26. Molar Tubes Molar tubes for segmental teeth movement technique are used to keep the molar upright but permitting free sliding of archwire through treatment to facilitate retraction of anterior teeth. Two type of molar tubes are available depending on the operator preference (Figure 7). A. SINGLE ROUND MOLAR TUBE 036" B. COMBINATION EDGEWISE AND ROUND TUBE (022"-028") The double tube assembly in B, positions the 036" round tube gingivally. The rectangular tube should be at the same level of the archwire slots in the premolar brackets. That will give the operator a better option to use either tube depending on the situation whether the premolar bracket need to be placed gingivally because of occlusial interference.

27. Placement of Twin-Edge Brackets. Brackets should be placed in the center of the labial or buccal surface of crowns, and in the middle third. (Figure 8)

28. Arch wires After treatment is initiated by using.016-.020" NiTi full arch wire full archwire bent from 020" round hard wire is used. This wire has four vertical loops bent mesial and distal to cuspids. It is a power arch which will provide depression and elongation movement, expansion or constriction control, and segmental teeth movement will be allowed by using heavy elastic forces. This archwire cease to be a source of segmental teeth movement after applying combination of intermaxillary and horizontal elastics. It also provides greater stability against the force of occlusion. Rectangular archwires Rectangular arch wire of 021"x 025 provide torque ability of anterior teeth and maximum friction and strength and stability. They are rarely used at the end of treatment in some cases. NiTi rectangular archwire could be used before to facilitate wire-bracket engagement.

29. SEGMENTAL TEETH MOVEMENT TECHNIQUE This technique is separated into three distinct phases in order to provide better understanding and learning of the mechanics, as well as to simplify the treatment process. Each phase has certain objectives that should be met before moving on to the next.

30. PHASE I (Initial Mechanics): Our major concern in this phase is to initiate teeth or individual tooth movement which will lead into preparation for segmental teeth movement mechanism. That include but not limited to rotation, leveling and anterior space closing. The orthodontic correction created during this stage is provided by full NiTi 016-020" archwires..016" full hared archwire with rotation loops could be used for better rotation control (Figure 11).

32. PHASE I OBJECTIVES: (Figure 11,12) 1. Rotation of crowded teeth: could be achieved by NiTi o16”,020" full archwires. 2. Leveling-could be achieved by full.016”, 020” NiTi archwire tightly and securely engaged into the bracket slot. 3. Closing of anterior spaces-could be achieved by elastomeric chain placed between teeth 020" NiTi full archwire after rotation and leveling have been accomplished. Of these objectives, closing anterior spaces involves only the incisors. Cuspids are not to be engaged with elastic chain in order not to round-trip them whenever anterior segment retraction is required.

34. PHASE II (Mid-Mechanics): The second phase is utilized to initiate the depression, the elongation, and anterio-posterior segmental teeth movements toward the proper vertical and sagital position (Figure 13) The objectives of Phase II 1. Opening the deep over bite-could be achieved by 020" round archwire with proper rocking chair curve in the upper and gable bent in the lower arch, and or high pull headgear engaged misial to the upper lateral incisor brackets. Metal ligature chain should be tightened between incisors to prevent space opening. 2. Closing the openbite-could be achieved by flat 020' round archwires with class II, class II mid-loop intermaxillary elastics or vertical elastics engaged to both upper loop and the lower midloop. 3. Maintaining all correction achieved during the first stage could be accomplished by securely fastening engagement of 020" wire to bracket's slots, and metal ligature chain to maintain space closing corrections. 4. Initiating the desired segmental teeth movement in the sagital plan- could be achieved by using light intermaxillary elastic force. 5. Initiating the desired expansion or constriction movements in the horizontal plan (correction of posterior cross-bite) could be achieved by expending or constricting archwire, and or by the application of posterior cross-elastic forces.

35. 6. Initiating correction of molar relationships could be achieved by using light intermaxillary elastic force, and horizontal elastomeric engaged between molar hook and first loop. The amount of rocking chair curve and gable depend on the severity of the over bite. Reverse curve or flat archwire may be necessary to close the open bite. 7. Proper axial inclination-could be achieved by upper rocking chair curved, lower gable bend, NiTi torquing auxiliary, and individual torque bars.

36. PHASE III (End-Tx Mechanics): (Figure 14) Phase III is started when bite opening, and proper axial inclination of anterior teeth has been achieved. Our main concern in this stage is to close posterior spaces and achieve class I molar relationships without disturbing the proper axial inclination of the anterior segment. This segmental teeth movement is generated by horizontal elastomeric and intermaxillary elastic force components, and other components produced by the proper archwire vertical control (upper rocking chair curve, lower gable bents, and high pull head gear).There is no Phase III in none extraction cases. The Objectives of phase III (Figure 14) 1. Maintaining all the correction achieved during stage I & II -could be achieved by securely fastening engagement of 020" wire to bracket's slots, metal ligature chain to hold space closing corrections, and proper archwire gable bent and rocking chair curve.

37. 2. Proper anterior segment sagital movement to establish class I cuspid relationship -could be achieved by horizontal or intermaxillary elastic forces, (Figure 14) in form of triangle engaged between both upper loops and lower midloop.

38. 3. Proper posterior segmental Horizontal movement to establish class I molar relationships, and close posterior extraction spaces - could be achieved by proper application of horizontal and inter maxillary elastic forces. Once proper cuspid relationship is established, vertical heavy elastics engaged to upper loops and lower mid-loop in form of triangle is used to maintain this relationship (Figure 14). 4. Midline correction-could be achieved by proper application of class II intermaxillary elastics on one side, and class III on the other (Figure 14A).

39. TECHNIQUE PLIERS Bird beak pliers The main plier used in the segmental teeth movement technique is designed by E.H. Angle for S.S. White Dental Company referred to as a no. 139, or “bird beak plier”. (Figure 15). The two tapering beaks-usually one round and one square are used for most loop and arch bending, and placing the archwires in the mouth. When forming loop, the wire should always be bent around the round beak. Archwires Bending-components Most archwires used in the Segmental teeth movement technique are bent from wire with a round cross-section. The anterior teeth aligned by using 016”, 020" NiTi full archwires or 016", 020" diameter, hard wire. Bite opening is accomplished by 020" full hard round wire. All archwires are constructed by bending two or more of the following components into a piece of wire.

42. TREATMENT OF CLASS I, ANTERIOR CROWDING WITH EXTRACTION OF THE FOUR FIRST PREMOLARS Treatment of class I anterior crowding with biprot-rusion cases are compared of the one with class II div 1 which both required extraction. Cephalometric analysis shows moderate class II skeletal relations in both ANB and WITS (Figure 27). This 13 years and 6 months old female orthodontic patient also has severe labial inclination of upper incisor MX 1/SN 112 and moderate labial position of lower incisor Mn 1 to AP +5mm with severely closed interincisal angle of 108. The dentoalviolare size-disharmony gives the patient a convex profile with prominent lips, (Figure 28).

43. The biprotrusion syndrome tend to be accompanied by a large and very functionally active lingual organ which puts limits to the retraction movement Of the anterior segment. Stage I of treatment started with placing 020" NiTi full arch wire to initiate individual teeth movement as preparation of segmental teeth movement mechanism (Fig 29-30).

44. All objectives of PHASE I are initiated by full 020" NiTi archwires tightly and securely engaged into the bracket slot (Figure 30). It is sometimes necessary to apply 016"with trapeze to help rotational control (Figure 31-32).

46. Mid-Tx Mechanics (Phase II) initiation of segmental teeth movement is achieved by proper application of class II mid-loop elastics and lower horizontal elastomeric chain on 020" full archwires with upper rocking chair and lower gables. The amount applied of theses forces depend on overbite and the severely of biprotrusion. The horizontal elastomeric chain is engaged between the anterior loop and molar's hook in the lower arch only (Figure 33).

47. Better correction will be observed during the first month in Phase I such as, better axial inclination, lower posterior space closure, and overbite correction (Figure 33-A). Upper rocking chair curve and lower gable bents are continued in combination with class II left class III right medium intermaxillary elastic to establish a midline correction. (Figure 33-A, 33-B). Horizontal lower elastomerics are added in (Figure 33-C).

48. In Phase III (End-Tx Mechanics), vertical elastics in form of triangle (Figure 33-D) help to maintain a proper cuspid relationship, while horizontal elastomerics are working to close posterior extraction spaces, mainly by driving the posterior segments misially (Figure 33-E).

50. FORCE COMPONENT ANALYSIS IN PHASE II In the lower arch (Figure 33), horizontal elastomeric chain H will distallize the anterior segment and misially drive the posterior one by tipping type of movement. The gable bent G distal to cuspid mid-loop will upright these segments. Class II Mid-loop elastic C will also help the act of gable bent and misial drive of posterior segment. The resultant of force components R will permit the desired segmental space closer by both posterior and anterior segments move bodily toward each other. In the upper arch (Figure 35), rocking chair curve R will help to intrude the anterior segment while -the posterior ones are maintained in the same position (preserve

51. anchorage). No upper horizontal elastomeric chain is engaged at this stage in order to preserve upper molar anchorage. Class II Med-Loop elastics E will tip the upper anterior segment distally. The resultant of force components L will permit the desired anterior segment bodily distalization movement. Using class II Mid-loop elastics E is helping the lower gable bent and it is used when overbite correction required is minimum.

52. FORCE COMPONENT ANALYSIS IN PHASE III Phase III (Figure 36) started as soon as proper overjet, overbite, and axial inclination of anterior segment have been accomplished. Horizontal elastomeric chain H with reduced upper rocking chair curve and lower gable bent G are applied to initiate posterior space closer by the act of the resultant force R (Figure 36). Intermaxillary elastics are used vertically in form of triangle (Figure 33-A) in order to maintain proper cuspids relationships by putting on the break on the anterior segment throughout posterior space closure. Upper rocking chair curve and lower gable bent are decreased in order to lose anchorage and achieve molar misial drive.