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Begg and straight wire: A combination approach to treatment
American
Journal
of ORTHODONTICS Volume 79, Number
ORIGINAL
6
June,
1981
ARTICLES
Begg and straight wire: A combination approach to treatment William J. Thompson, Bradenton, Fla.
D.D.S.
Orthodontic appliances should be designed to satisfy goals for denture, patient, and doctor. An appliance that is able to achieve these goals more closely approaches the ideal treatment system. Analysis of appliances of the Begg and straight wire tvpes indicates that each treatment system has significant advantages and that the advantages of one system frequently are the disadvantages of the other. A technique that uses both the tipping principles of Begg and the bodily movement principles of the straight wire type of appliance has been designed and clinically evaluated. The unique capability of the combined treatment approach is in the mechanical design of the new combination four-stage bracket. A description of the appliance and the technique, as well as a clinical case presentation, is included in this article. Key words: Tipping,
precision, movements,
combination,
treatment
B
egg appliances and appliances of the straight wire type have been known to produce fine orthodontic results. An analysis of these appliances, however, shows that each has unique characteristics which can be advantages or disadvantages in a total treatment program. The objective of this article is to describe the advantages and disadvantages of the classic Begg and straight wire appliances and to suggest a treatment approach that uses the advantages of each while minimizing the disadvantages. The comparisons of the straight wire appliance in the discussion will relate to the methods of using straight, continuous arches with sliding mechanics and full-size finishing wires where possible. The comparisons of the Begg appliance are based upon use of the tradi0002.9416/81/060591+19$01.90/0
0
1981 The C. V. Mosby Co.
591
592
Am. J. Orthod. June 1981
Thompson
Fig. 1A. Bite opening
is very effective into the freeway space and intrusion appliance in place. Bottom, Dentition
with the Begg of the incisors. after treatment.
technique, involving elevation of the lower lop, Dentition before treatment. Middle,
molar Begg
tional Begg system employing round wires, anchor bends, Class II elastics, and auxiliaries as necessary. A concise description of the essential procedures with a combination bracket (Begg and straight wire) is provided. Both static and functional occlusions are of importance to orthodontists. Since the early discussions of occlusion by Brodie and Thompson,’ orthodontists have become increasingly aware of and concerned about functional occlusal harmony. In recent years, the literature has been filled with research and clinical material about occlusion and function in orthodontics, relating it to diagnosis, treatment planning, appliances, and retention.2-s Much of the clinical material related occlusion to angulation, axial rotation, and torque of teeth in order to form maximum intercuspation. In search of an appliance technique capable of an individualized, comprehensive approach to each patient’s treatment, the orthodontist must satisfy goals in three principal areas, namely, for the denture, the patient, and the doctor. The significance of these goals should be shared by both the patient and the orthodontist. Each appliance system, however, does not necessarily provide the optimum effectiveness in accomplishing all of these mutual goals. i”-is The orthodontist must carefully evaluate what his appliance can do and be willing to modify his technique to increase its effectiveness toward satisfying the maximum number of mutual goals. In order to increase the total effectiveness of a treatment program, it is suggested that the favorable mechanical capabilities of one or more appliance systems be combined into a synergistic type of mechanics. One such treatment approach might involve light, rapid tipping forces to correct gross changes in tooth position at one stage in treatment, while more rigid and precise appliances are used later in treatment to produce maximum tooth
Volume 79 Number 6
Begg
Fig.
18.
For legend,
see
Fig. 1A
Fig.
1C. For legend,
see
Fig.
and
straight
wire
593
1A.
detailing and occlusal intercuspation. Such a combination of treatment capabilities enables the practitioner to achieve selectively or collectively, in an optimum way, the various goals for the denture, patient, and doctor. The Begg technique uses a pin-and-tube bracket which facilitates one-point contact. Using continuous, small-diameter round wires, elastics, and springs, the force system is
594
Am. J. Orrhod. June 1981
Thompson Begg Appliance
<
Force
System
Physiologic
Unipoint contacts Anchor bend action Archwire action Auxiliary wire action Tipping forces Intrusive forces Extrusive forces Rotational forces > I’
Fig. 2. In the differential force system, dynamic ship of the appliance forces and the physiologic critical because of the free, tipping movements,
Force
System
Muscle action Tooth morphology & mass Cuspal interlock Freeway & functional paths Occlusal forces & migration Bone density Growth Habits 3 ’ /, fl
3
II
anchorage is established by the intricate interrelationforces. The balance between the two force systems light forces, and reduced friction.
is
designed to provide tipping movement. The edgewise bracket with continuous rectangular wires facilitates a bodily type of movement with torque control.“. Is Each of the systems has produced satisfactory orthodontic results over the years, and each has undergone a multitude of improvements. The most current evolutionary change in the edgewise system is the addition of the straight wire type of appliance.‘0, 13. 20--22Each has its unique advantages and disadvantages and can be shown to provide certain favorable treatment responses. Use of both the tipping and bodily movements at specific times in treatment does produce a diversified treatment system that can be an unusually effective combination. The Begg system, developed by Dr. P. Raymond Begg,12. 23,24was originally defined as a differential-force, light-wire appliance. Differential force can be described as a dynamic interaction of physiologic and appliance forces that form an anchorage system and a moving system in treatment. A concept that includes dynamics of function and differential dental anchorage is based upon the philosophy that muscle forces, functional forces, inclined planes and occlusal forces, other physiologic forces, and even nonphysiologic forces, such as habits, are placed in action or reaction with Begg appliance forces produced from anchor bends, wire design, bracket contact, and elastic pressures. Properly designed, the differential system permits effective posterior anchorage stability with light, rapid tipping and intrusion of anterior teeth. The predictability of many tooth movements may be due to the direct influence of the forces of physiology that are an effective part of the true differential system. Several past clinical studies have documented the capability and predictability of the Begg system to produce consistent treatment changes. 8, 11, 12,25-31 Clinicians familiar with the Begg system recognize their ability to open bites, retract incisors, torque incisors, and upright roots (Figs. 1.4, 1B, and 1 C). It is also significant that the maximum flexibility of the appliance and the greatest degree of tooth movement occur in the early stages of treatment. These stages-Stages I and B-are the periods of treatment in which differential force is critical, tooth movements are very rapid, and the physiology of freeway and functional occlusion are of paramount importance in establishing maximum posterior anchorage. 32-35Personal observations and discussions with other Begg clinicians have frequently confirmed the fact that the mechanics in Stage I and Stage II are the keys to success in Begg treatment, since they determine the effective bite opening, the optimum anteroposterior positioning of incisors, and stability of the molars.
Vol!me 79 Number 6
Begg
and
straight
wire
595
Fig. 3. Frequently after Stage III additional movements are needed to establish optimal finished occlusion. These include such movements as establishing overbite (A), getting proper molar occlusion (B), setting even torque (C), and correcting undesirable incisor drift (D).
It must be realized at this point that these favorable characteristics of Begg treatment occur in the early periods of treatment, during unraveling, bite opening, and anterior retraction, when physiologic tipping of teeth is desired and most effective (Fig. 2). Little has been said about the Begg appliance in the finishing stages. Probably the most difficult part of Begg treatment is the finishing period, and this problem area has been
Am. J. Orthud. June 1981
595 Thompson A.
B.
Favorable characteristics of Begg appliances 1. Rapid bite opening 2. Rapid anterior alignment 3. Retraction of six anteriors en masse 4. Supportive extraoral anchorage not recommended routinely 5. Anterior root torque is unlimited by bracket 6. Predictable molar and incisor positioning Favorable characteristics of straight wire appliances 1. Precision arch coordination is routine 2. Precision intercuspation is routine 3. Buccolingual root torque is routine 4. Simplified finishing wires are routine 5. Minimal wire adjustments in finishing
Fig.
4. Begg
and straight
wire
appliances
Unfavorable characteristics 1. Posterior root torque is difficult 2. Three-dimensional arch coordination is difficult 3. Maintaining rotations is difficult 4. Finishing intricacies are difficult 5. Maintaining uprighting and torque is difficult
Unfavorable characteristics 1. Rigid appliance due to interbracket distance 2. More friction with sliding mechanics 3. Additional supportive anchorage recommended 4. Segmental retraction of anterior teeth 5. Forward tipping of incisors in continuous wire leveling 6. Prolonged bite-opening mechanics have
distinctly
different
characteristics
addressed before.“6 Control of buccolingual torque on posterior teeth is difficult in the Begg system and requires special auxiliaries to achieve good occlusal position. The ease of tipping on the single-point contact tends to permit undesirable tooth movements during the finishing periods. These movements can be produced by occlusal forces, functional interferences, damaged or bent arch wires, habits, and other minute, extraneous forces. The forces are capable of opening spaces, tipping teeth, and generally producing undesirable movements which frequently require additional appointments and adjustment procedures to obtain the optimum occlusal finish. Stage IV movements in Begg treatment are, theoretically, those added adjustments which are needed to obtain the optimum finish to the occlusion.:s6 It should be noted here that these precise finishing movements are late treatment procedures and are distinctly different from the rapid, gross changes achieved so effectively by Begg technique at the beginning of treatment (Fig. 3). Appliances of the straight wire type appear to have some distinct advantages over the Begg system at certain points of treatment.22x 3i, 38 These are principally related to the precision type of bracket and arch wire design. The wider twin bracket with the shorter interbracket distance used in some systems increases the rigidity of the continuous straight wire. It tends to increase the forces applied interdentally, increases the friction, and places positive three-dimensional forces and couples on the teeth. The rigidity of the straight wire, although having the potential of a more precise appliance with closer tolerance or fitting, has certain mechanical disadvantages in early alignment and leveling procedures. The inflexibility and friction of the appliance are magnified in the initial arch wire sizes because of the significantly greater angular position of the slots produced by the malposi-
Volume 79 Number 6
Begg
Fig.
5. Four
brackets
are designed
to accommodate
all teeth
and
except
straight
wire
597
molars.
tion and tipped teeth in the original malocclusion. The continuous leveling arch wires in the greatly angulated straight wire slot sequence set up extraneous forces among the teeth which tend to produce leveling by forward movement of anterior teeth.3g Unlike the single-point Begg bracket, the teeth cannot tip freely into extraction sites, and the typical intrusion and lingual tipping of incisors seen in the Begg treatment are not evident. In addition, anchorage support from an extraoral or intraoral appliance is frequently recommended to control the diversified forces generated in the irregular-slot brackets as alignment or retraction of teeth is performed. Bite opening in conventional straight wire mechanics is not as rapid as it is in the Begg system, where bite opening is effectively undertaken early in treatment by molar elevation and incisor intrusion which occur simultaneously with the en masse retraction of incisors. In spite of the apparent difficulties that can arise during the early periods of treatment with the straight wire appliance, it has been shown to produce fine precision and quality of occlusion in the finishing of treatment. 13, 22 The ability to place teeth closer to proper occlusal position with preangulated and pretorqued brackets with less arch wire manipulation is a definite treatment advantage. The heavier forces produced over shorter interbracket distances with precisely fitting rectangular wires in a rectangular slot establish excellent positive control in three dimensions, provide precise movements, and eliminate the undesirable tipping frequently seen during finishing procedures in a Begg system. In addition, the three-dimensional capability of the rectangular wire does provide a more accurate means of achieving total coordination of arch wires in both arches to provide optimum occlusal intercuspation. In this overview of Begg and continuous straight-wire appliances it appears that advantages and disadvantages of each system are due to the inherent characteristics in the
598
Am. J. Owhod.
Thorrpson
Junr
1981
compensation
Fig. 6. Straight Angulation.
wire
control
is designed
into
the
brackets.
A, Torque.
B, Input
compensation.
C,
design of the two systems. Each is constructed to perform one function best-Begg to produce gross movements rapidly with tipping, straight-wire to perform precise bodily movement over shorter distances in a force system of a more static nature. The Begg system is rapid in early treatment but becomes more cumbersome in the finishing stages. The straight wire system is prone to complications in early periods of treatment but is efficient in the final finishing adjustments (Fig 4).
Volume 19 Number 6
Begg
and
straight
wire
599
/ All upper brackets
Lower 2nd bicuspid brackets
Lower cuspid through 1st bicuspid brackets
Lower anterior brackets
Fig. 7. Each four-stage bracket is indexed for easy identification. (Identification distal-occlusal.) On Dyna-Bond II foil/mesh bonding bases, a red dot for maxillary mandibular brackets is on the distal-gingival corner of the base for all assemblies upper premolar and lower second premolar can be identified by a colored dot aspect of the base and on the chimney of the bracket where the lock pin enters. have no marking at all.
marks and through on the Lower
are toward the a black dot for canines. The distal-gingival first premolars
An appliance design that captures the advantages of both systems and reduces the disadvantages of both is the topic of discussion in the remaining part of this article. A new bracket concept and a treatment approach will be described. The new appliance enables the orthodontist to combine both the tipping and bodily movement principles of mechanics. The system permits the use of pure Begg mechanics in that part of treatment and in those cases in which it is most effective. It also permits the use of a straight wire appliance in the same cases or in any cases in which a rigid, preangular-pretorqued finishing procedure is desired. The dual capability of the appliance system is due to a combination bracket design* in which the lower third of the bracket is a Type 256 Begg bracket and the upper two-thirds of the bracket is a 0.018 by 0.025 inch straight wire slot with in-and-out positioning, preangulated and pretorqued (Figs. 5, 6, and 7). The Begg slot will accept all auxiliaries and arch wires used in Begg treatment and it performs as a typical Begg bracket in relation to tipping, bite opening, incisor and molar positioning, and torque. The appliance is set up in the standard manner with the 0.036 inch Begg tube placed gingivally on the first molars. All Begg slot heights, other than the molars, are dictated by the edgewise slot and, as such, are 1 to 1.5 mm. more gingival *Experimental and 7).
design
and research
development
performed
by Unitek
Corporation,
Monrovia,
Calif.
(Figs.
5,6,
Am
BRACKET
“‘,CANlNES ---UPPER Fig.
POSITIONING
4 to 4+mm LATERALS 8A. Bracket
J. Onhod. June 19x1
3mm
positioning
and
angulation.
than in a routine Begg banding. It is absolutely essential to set up the straight wire slot so that on the straight wire series the wire is level from the molar tube to all other brackets. In clinical preparation, it is desirable to band the molars first. Slight variations in the dimension from molar tube to cusp tip will exist because of anatomic differences, but a cusptip-to-tube distance of 3.5 mm. is a desirable starting point. If 3.5 mm. is acceptable, then all other edgewise slots must also be at 3.5 mm. except those on the canines and lateral incisors. Upper and lower canine brackets are placed gingivally 0.5 to 1 mm. more, depending on tooth size and shape. Such a position promotes canine-protected occlusion. The upper lateral incisors are placed 0.5 mm. more incisally to free them from interferences on the working occlusal movements. Each tooth must receive the specific brackets designed for it so that angulation, torque, and the in/out compensation are correct (Figs. 8A and 8B). The 1 to 1.5 mm. increased gingival positioning of the Begg slot does not seem to affect the bite-opening or tipping characteristics of Begg treatment. Free tipping is made very effective by means of a specially tapered bracket slot (Fig. 9). Also, special bypass pins and safety lock pins are available to reduce binding. The pins used are of a special length, since the width of some of the combination brackets is larger than a routine 256 bracket. The pin length is slightly greater in order to clear the tie wings of the edgewise part of the bracket, especially on the maxillary incisors. Begg molar tubes are kept gingivally and can be obtained with convertible straight wire tubes on the lower molar. The convertible tubes provide for desired Class II elastic hooks during Stages I, II, and III. They can be adapted to function as a routine straight
Volume 79 Number 6
Begg
IV
STAGE -10”
-10”
Fig.
9. Tipping
is possible
8B.
because
straight
wire
601
TORQUE -7”
-70
(-1 Fig.
and
Four-stage
Lab.
-7”+3O
root
c7”
torque
torque.
of the tapered
slot in the Begg
bracket.
wire type of bracket when the straight wire system is continued with first and second molars. It is not recommended that second molars be incorporated into the Begg system initially. All Begg treatment should be built around the first molar as the anchor unit, since experience shows that this is the most effective differential anchorage position and the most desirable for bite-opening mechanics of the Begg philosophy. After the bite is opened and retraction of incisors has been completed, the second molars can be banded without altering the anchorage or bite-opening potential of the system. When the appliance is properly and accurately constructed, the system is set up so that
602
Thompson
Am. J. Orthod. June 1981
Fig. 10. The combination four-stage appliance effectively controls the routine Stages I, II, and III of pure Begg mechanics and can then be transformed into a pure straight wire appliance by using the preadjusted edgewise slots. A, Before treatment. 6, Stage I. C, Stage II.
all edgewise slots are positioned for accepting a straight arch wire. The angulation, tip, and torque are comparable to current straight wire systems. Ligation of the wire can be done routinely with ligature wire or elastic modules. The lower molar combination tube permits ease of passing from first to second molars. Headgear tubes are available if desired. Use of the edgewise portion of the bracket is not begun in most instances until late in Stage III. Clinical experience with the combination bracket indicates that the Begg portion of the bracket is highly successful and fulfills all the essentials of a true 256 type slot. The treatment procedures necessitate the use of pure Begg type principles when the Begg slot is being used. All arch wire forms, anchor bands, bypass bends, and elastic forces should be similar to a routine Begg treatment approach. I*, N* 30 Because of the difference in the physical characteristics of the bracket parts, any attempt to alter the Begg treatment principles by switching slots or forces is prone to problems and anchorage difficulty. All Stage I, II, and III objectives should be followed, and this can be done effectively only if free tipping is exercised within the Begg slot (Fig. 10). It is recommended that treatment be initiated with routine 0.016 inch round Australian wire (orange special plus) using 40- to 45-degree anchor bends and 2% to 3 ounce Class II elastics. Vertical loop arches are still suggested as the initial wire if gross irregularity exists and bite opening is desired immediately. A free-tipping appliance is essential, and all recorded problems which can affect tipping and bite opening must be controlled. “, 32*” For the best physiologic response to the appliance, the Begg procedures should be carried completely through Stage I and Stage II and at least partly through Stage III. Routine 0.016, 0.018, and 0.020 inch round wires, toe in or out, anchor bends, and intra- and interarch elastics are used as recommended in Begg therapy.
Volume 79 Number 6
Fig. 10 (Cont’d). (0.018 by 0.025
Begg and straight wire 603
D, Pre-Stage III. E, Stage Ill. F, Stage inch nitinol). H, Band removal.
IV (braided
rectangular
wire).
G, Stage
IV
At the end of Stage II, the occlusion should show the typical Stage II characteristics: spaces closed, bite opened to an edge-to-edge relationship, molars Class I or better, incisors retracted and tipped lingually, all rotations and ectopically repositioned teeth overcorrected. Stage III is essential; the combination bracket is not intended as a substitute for this phase of treatment. When the occlusal relationship and treatment objectives are ready for Stage III, the severe tipping of the buccal segments and incisors, which is typical and characteristic of Begg therapy, produces a very irregular pattern to the angulated rectangular slots. The angulation is so severe in some cases that placement of leveling wires is contraindicated (Figs. 1IA and 1 lL?). Short interbracket distance between the edgewise slots increases force values and leveling forces. A common difficulty is the tipping of teeth mesially into a more bimaxillary relationship as seen in routine edgewise leveling procedures with full appliancing and no elastics or coil springs.40 The unwanted movement can
604
Am. J. Orthod. June 1981
Thompson
Fig. 11A. Angulation of the edgewise slot at the beginning of Stage III contraindicates placement of the main arch wire in this slot. Routine Stage Ill movements must be used until a straight arch wire can be inserted with the least number of extraneous leveling forces and with a reduced amount of force. An angulation of 5 to 7 degrees seems adequate.
STAGE III 3o”to40~
------
ZT?cF 0 0= -------_‘c----..-s -- -- ---HOR. Fig.
118.
be eliminated by undertaking adequate uprighting in Stage III to level the straight wire slots before a straight wire is placed (Fig. 12). Stage III should be carried out with 0.020 inch base wires, constricted in the maxillary arch, and having reduced anchor bends in a typical Begg program. All Begg uprighting springs and torquing auxiliaries can be placed in the Begg slot with no difficulty. The Stage III mechanics should be continued until the occlusion approaches a fairly level plane and the edgewise slots are almost parallel. This is a subjective decision by the orthodontist, but clinically it seems to be within 5 degrees of the horizontal. When the alignment has reached this degree of leveling and uprighting, the Begg portion of treatment has ceased. The Begg wires and springs are removed and the remaining treatment is done in the rectangular slot with a straight arch wire. The new wires may be braided round, braided rectangular, nitinol, routine round, or edgewise wires up to 0.018 by 0.025 inch. Usually one braided or small round wire series is needed before a rectangular wire can be placed for final torque control. Some cases will require adjustments in the final rectangular wire to maintain proper anterior incisor torque. Since Begg treatment has excellent torquing capability and the degree of torque is dependent on the clinician’s decision, the predetermined amount of torque in the straight wire slot may be inadequate to meet the degree of torque established
Volum<~ 79 6
Number
Begg
und
straight
wire
605
Fig. 12. The unique advantages of Begg treatment can best be accomplished by use of routine Begg tipping mechanics. Maximum anchorage control and minimum forward movement of incisors necessitate adherence to these mechanical principles until a straight wire can be inserted without adverse effect. Generally, a braided steel wire or a 0.016 inch round or square nitinol wire can be inserted when the uprighting has leveled the rectangular slots to within 5 to 7 degrees of the level occlusal plane. A, Before treatment. B, Stage I. C, Stage II.
in Stage III by the orthodontist. If the standard 7-degree torque is thought to be inadequate to meet the clinician’s needs, the torque for the incisors can be obtained in increased amounts as in other systems. We feel that banding of lower second molars is contraindicated by early Begg treatment because of the philosophy of mechanics involved in bite opening. Second molars are not used for anchorage or bite opening, and their use can even interfere with these functions because of the more distal placement of vertical forces and the reduction of the vertical extrusive component of the Class II elastics. Banding of second molars is, however, often essential for proper marginal ridge control, to improve the buccolingual position of the second molars, and to act in functional balance. These movements are best accomplished in late Stage III and with the rectangular straight wire mechanics. The second molars can be banded or bonded during Stage IV, and sectional 0.014, 0.016, or 0.018 inch wires can be used to begin leveling without interfering with Stage III. The second molars can be bonded or banded with routine straight wire tubes placed at the same occlusogingival positions as the first molar rectangular tube. Since the Stage III arches are in the round tube, the sectional auxiliary wires to level the second molars can be placed in the rectangular tubes. When the Stage III is removed and straight wire treatment initiated, the second molars are level and ready for incorporation into the finishing mechanics (Fig. 13). Some criticism of the rigid finishing procedures has come forth from a few Begg clinicians and others.22. 37, ax S ome believe that loose, free-tipping appliances are more
606
Thompson
Am. J. Orthod. Jurw 1981
Fig. 12 (Cont’d). D, Stage III. E, Stage IV (0.016 inch round wires). F, Stage IV (0.018 inch round and 0.016 by 0.025 inch lower). G, Stage IV (0.018 by 0.025 inch wires). H, Band removal.
upper
desirable to encourage physiologic or functional settling of occlusion. The idea of a functional occlusal settling is good, but the rectangular finishing rigidity does not alter this concept. Optimum occlusal settling is possible only if the teeth are in their best threedimensional position and in best relation to the functional paths. These are established most accurately with proper torque, uprighting, and arch form. When this is accomplished in the straight wire segment of the bracket, any finishing or band-removal technique is enhanced. Segmental band removal, positioners, or light 0.012 inch functional settling wires are all effective. Ideal finishing is completely dependent upon the best achievement of the Stage I, II, and III goals where the physiologic harmony of Begg treatment is produced. These stage objectives are designed to complement the tipping movements, force vectors, and force values of the appliance to use freeway space and molar elevation,
Volume 19 Number 6
Begg
STAGE
STAGE
Fig.
13. Second-molar
and
straight
wire
607
III
Ip
control.
to retract incisors into a proper functional environment, and to establish the optimum anteroposterior position of the denture.““, 30, 31 We have observed additional favorable findings in the clinical application of the combination system. Changes in the amount of time required to accomplish specific stage objectives can vary when compared to traditional Begg treatment. Stage III can be altered because of the shortening of the usual uprighting periods by finishing the uprighting and torque in the rectangular slot. In Class I extraction cases, where Stage II closure may be minimal and uprighting of canines frequently amounting to only a few degrees, Stage III may be completely eliminated and only rectangular finishing may be needed. Use of the edgewise slot in one arch and the Begg slot in another arch provides the clinician with different anchorage and movement combinations where bodily movement and free tipping can be employed simultaneously. It is also possible to reduce looped arches in Stage I by using sectional auxiliary arch wires, such as flexible twisted wire or nitinol leveling wires, in the edgewise slot on the four incisors to initiate alignment while the Begg base arch is used to obtain bite opening and retraction of canines and incisors. In nonextraction cases, Stage II and Stage III may be significantly shorter and possibly nonexistent because space closure in Stage II is usually minimal, uprighting is needed only on certain individual teeth, and torque requirements are reduced. It is often possible to enter the rectangular slot with the main wire very early in the nonextraction cases and to control most of the uprighting and torque with only the straight wire type of angulated and torqued slot. Another advantage of the combination system bracket is the potential in transfer of cases under treatment. Routine transfer of Begg cases to a few areas of the country is difficult because of the lack of treatment facilities and the scarcity of clinicians who have had experience with the technique. Frequently, patients are required to travel longer distances or to have appliances changed in order to continue treatment. In a combination system, an orthodontist can switch to a slot he feels best able to control. An astute edgewise clinician can go to the rectangular slot and, using appropriate anchorage design, sectional wires, etc., continue treatment with minimal inconvenience to the patient or the doctor. Clinical use of the combination Begg and straight-wire type of appliance has been very
608
Thotnpsor~
gratifying. The optimum treatment capabilities of two excellent treatment approaches are united in a common technique. The combination bracket appears to have good potential for clinical orthodontics. Much can be expected in new designs and combinations as the idea progresses. This article has been presented to familiarize clinicians with the principle. Perhaps it will stimulate
others
to seek
improvements
in design
and
techniques.
1 acknowledge, with thanks, The University of Florida Department of Orthodontics and Mr. Conrad Bamgrover and Mr. George Augur of Unitek Corporation for their assistance in obtaining some of the line drawings for this paper. I also thank Dr. William Baker for his assistance in the development of the combination bracket concept REFERENCES 1. Brodie, A. C., and Thompson, J. R.: Factors on the position ofthe mandible, J. Am. Dent. Assoc. 29: 925, 1942. 2. Aubrey, R. B.: Occlusal objectives in orthodontics, AM. J. ORTHOD. 74: 162-175. 1978. 3. Ingerwall, Ben@: Functionally optimal occlusion, the goal of orthodontic treatment, AM. J. ORTHOD. 70: X0-90, 1976. 4. McHorris, W. H.: Occlusion with particular emphasis on the functional and parafunctional role of anterior teeth. Part I. J. Clin. Orthod. 13: 689-701, 1979. 5. McHorris, W. H.: Occlusion with particular emphasis on the functional and parafunctional role of anterior teeth. Part II, J. Clin. Orthod. 13: 608-620, 1979. 6. Parker, W. S.: Centric relation and centric occlusion-An orthodontic responsibility, AM. J. ORTHOD. 74: 481-500, 1978. 7. Roth, R. H.: Temporomandibular joint pain-Dysfunction and occlusal relationships, Angle Orthod. 43: 136-153, 1973. 8. Weber, F. N.: Clinical investigations related to the rise of the Begg technique at the University of Tennessee, AM. J. ORTHOD. 59: 24-36, 1971. 9. Williamson, E. H., Caves. S. A., Edenfield, R. .I., and Morse, P. K.: Cephalometric analysis: Comparisons between maximum intercuspation and centric relation, AM. J. ORTHOD. 74: 672-6?7, 1978. 10. Andrews, L. F.: The straight wire appliance, origin, controversy, commentary, J. Clin. Orthod. 10: 99-l 14, 1976. II. Barrer, H. G.: A survey of Begg treatment, AM. J. ORTHO~X 40: 494-506, 1963. 12. Begg, P. R., and Kessling. P. C.: Begg orthodontic theory and technique, ed. 3, Philadelphia, 1977, W. B. Saunders Company. 13. Magnus. B. W.: The straight wire concept, AM. J. ORTHOD. 73: 541-550, 1978. 14. Mulligan, T. F.: Common sense mechanics, J. Clin. Orthod. 13: 588-594, 1979. 15. Mulligan, T. F.: Common sense mechanics. Part II, J. Clin. Orthod. 13: 676-683, 1979. 16. Ricketts, R. M.: Bioprogressive therapy as an answer to orthodontic needs. Part I, AM. J. ORTHOD. 70: 241-268, 1976. 17. Ricketts. R. M.: Bioprogressive therapy as an answer to orthodontic needs. Part II, AM. J. ORTHOD. 70: 359-397, 1976. 18. Sims, M. S.: Conceptual orthodontics, AM. J. ORTHOD. 71: 431-439, 1977. 19. Thurow, R. C.: Edgewise orthodontics, ed. 3, St. Louis, 1972, The C. V. Mosby Company. 20. Andrews, L. F.: The six keys to occlusion, AM. J. ORTHOD. 62: 269-309, 1972. 21. Andrews. L. F.: The straight wire appliance, Syllabus of philosophy and technique, 1975, L. F. Andrews. 22. Meyer, M. M., and Nelson, G.: Preadjusted edgewise appliances: Theory and practice. AM. J. ORTHOD. 73: 485-498, 1978. 23. Begg, P. R.: Light arch wire technique employing the principles of differential force, AM. J. ORTHOD. 47: 30-48, 1961. 24. Begg, P. R.: The differential force method of orthodontic treatment, AM. J. ORTHOD. 71: l-39, 1977. 25. Barrer, H. G.: Evaluation of the Begg technique 5 years later, Begg J. Orthod. Theory Treat. 3: 29-34, 1964.
Volumr 79 6
Number
26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41, 42. 43.
Begg
and
straight
wire
609
Barton, J. A.: A cephalometric appraisal of cases treated with edgewise and Begg technique, Angle Orthod. 43: 119-126, 1973. Daugremond, Chester: The Begg light wire treatment; a comparative study. Unpublished data, 1969. Parker, W. S.: A consideration of the pure Begg technique, Angle Orthod. 39: l-10, 1967. Swain, B. F.. and Ackerman, J. L.: An evaluation of the Begg technique, AM. J. ORTHOD. 55: 668-687, 1969. Thompson, W. J.: A cephalometric appraisal of incisor positioning with the Begg appliance, Angle Orthod. 44: 171-177, 1974. Thompson, W. J.: Occlusal plane and overbite, Angle Orthod. 49: 47-55, 1979. Barrer, H. G.: Treatment problems, source and elimination, Begg J. Clin. Orthod. Theory 4: 59-64, 1968. McDowell, C. W.: Static anchorage in the Begg technique, Angle Orthod. 39: 162-170, 1969. McDowell, C. W.: A reappraisal of cephalometrics. Part I, J. Clin. Orthod. 4: 82-92, 1970. McDowell, C. W.: A reappraisal of cephalometrics. Part II, J. Clin. Otthod. 4: 134-145, 1970. Thompson, W. J.: Begg Stage IV, Begg J. Orthod. Theory Treat. 5: 17-24, 1969. Begg, P. R.: Personal communication, January, 1980. Dellinger, E. L.: A scientific assessment of the straight wire appliance, AM. J. ORTHOD. 73: 290-299, 1978. Baldridge, Doyle: Leveling the curve of Spee: Its effect on mandibular arch length, J. Pratt. Orthod. 3: 26-41, 1968. Begg. P. R.: Choice of bracket for the light wire technique, Begg J. Orthod. Theory Treat. 1: 1 I-18, 1962. Thompson, W. J.: Current application of Begg mechanics, AM. J. ORTHOD. 62: 245-271, 1972. Williamson, E. H.: Occlusion: Understanding or misunderstanding, AM. J. ORTHOD. 46: 86-93, 1976. Timm, T. A.. Herremans, E. L., and Osh, M. A.: Occlusion and orthodontics, AM. J. ORTHOD. 70: 138-145. 1976.
Journal
of ORTHODONTICS Volume 79, Number
ORIGINAL
6
June,
1981
ARTICLES
Begg and straight wire: A combination approach to treatment William J. Thompson, Bradenton, Fla.
D.D.S.
Orthodontic appliances should be designed to satisfy goals for denture, patient, and doctor. An appliance that is able to achieve these goals more closely approaches the ideal treatment system. Analysis of appliances of the Begg and straight wire tvpes indicates that each treatment system has significant advantages and that the advantages of one system frequently are the disadvantages of the other. A technique that uses both the tipping principles of Begg and the bodily movement principles of the straight wire type of appliance has been designed and clinically evaluated. The unique capability of the combined treatment approach is in the mechanical design of the new combination four-stage bracket. A description of the appliance and the technique, as well as a clinical case presentation, is included in this article. Key words: Tipping,
precision, movements,
combination,
treatment
B
egg appliances and appliances of the straight wire type have been known to produce fine orthodontic results. An analysis of these appliances, however, shows that each has unique characteristics which can be advantages or disadvantages in a total treatment program. The objective of this article is to describe the advantages and disadvantages of the classic Begg and straight wire appliances and to suggest a treatment approach that uses the advantages of each while minimizing the disadvantages. The comparisons of the straight wire appliance in the discussion will relate to the methods of using straight, continuous arches with sliding mechanics and full-size finishing wires where possible. The comparisons of the Begg appliance are based upon use of the tradi0002.9416/81/060591+19$01.90/0
0
1981 The C. V. Mosby Co.
591
592
Am. J. Orthod. June 1981
Thompson
Fig. 1A. Bite opening
is very effective into the freeway space and intrusion appliance in place. Bottom, Dentition
with the Begg of the incisors. after treatment.
technique, involving elevation of the lower lop, Dentition before treatment. Middle,
molar Begg
tional Begg system employing round wires, anchor bends, Class II elastics, and auxiliaries as necessary. A concise description of the essential procedures with a combination bracket (Begg and straight wire) is provided. Both static and functional occlusions are of importance to orthodontists. Since the early discussions of occlusion by Brodie and Thompson,’ orthodontists have become increasingly aware of and concerned about functional occlusal harmony. In recent years, the literature has been filled with research and clinical material about occlusion and function in orthodontics, relating it to diagnosis, treatment planning, appliances, and retention.2-s Much of the clinical material related occlusion to angulation, axial rotation, and torque of teeth in order to form maximum intercuspation. In search of an appliance technique capable of an individualized, comprehensive approach to each patient’s treatment, the orthodontist must satisfy goals in three principal areas, namely, for the denture, the patient, and the doctor. The significance of these goals should be shared by both the patient and the orthodontist. Each appliance system, however, does not necessarily provide the optimum effectiveness in accomplishing all of these mutual goals. i”-is The orthodontist must carefully evaluate what his appliance can do and be willing to modify his technique to increase its effectiveness toward satisfying the maximum number of mutual goals. In order to increase the total effectiveness of a treatment program, it is suggested that the favorable mechanical capabilities of one or more appliance systems be combined into a synergistic type of mechanics. One such treatment approach might involve light, rapid tipping forces to correct gross changes in tooth position at one stage in treatment, while more rigid and precise appliances are used later in treatment to produce maximum tooth
Volume 79 Number 6
Begg
Fig.
18.
For legend,
see
Fig. 1A
Fig.
1C. For legend,
see
Fig.
and
straight
wire
593
1A.
detailing and occlusal intercuspation. Such a combination of treatment capabilities enables the practitioner to achieve selectively or collectively, in an optimum way, the various goals for the denture, patient, and doctor. The Begg technique uses a pin-and-tube bracket which facilitates one-point contact. Using continuous, small-diameter round wires, elastics, and springs, the force system is
594
Am. J. Orrhod. June 1981
Thompson Begg Appliance
<
Force
System
Physiologic
Unipoint contacts Anchor bend action Archwire action Auxiliary wire action Tipping forces Intrusive forces Extrusive forces Rotational forces > I’
Fig. 2. In the differential force system, dynamic ship of the appliance forces and the physiologic critical because of the free, tipping movements,
Force
System
Muscle action Tooth morphology & mass Cuspal interlock Freeway & functional paths Occlusal forces & migration Bone density Growth Habits 3 ’ /, fl
3
II
anchorage is established by the intricate interrelationforces. The balance between the two force systems light forces, and reduced friction.
is
designed to provide tipping movement. The edgewise bracket with continuous rectangular wires facilitates a bodily type of movement with torque control.“. Is Each of the systems has produced satisfactory orthodontic results over the years, and each has undergone a multitude of improvements. The most current evolutionary change in the edgewise system is the addition of the straight wire type of appliance.‘0, 13. 20--22Each has its unique advantages and disadvantages and can be shown to provide certain favorable treatment responses. Use of both the tipping and bodily movements at specific times in treatment does produce a diversified treatment system that can be an unusually effective combination. The Begg system, developed by Dr. P. Raymond Begg,12. 23,24was originally defined as a differential-force, light-wire appliance. Differential force can be described as a dynamic interaction of physiologic and appliance forces that form an anchorage system and a moving system in treatment. A concept that includes dynamics of function and differential dental anchorage is based upon the philosophy that muscle forces, functional forces, inclined planes and occlusal forces, other physiologic forces, and even nonphysiologic forces, such as habits, are placed in action or reaction with Begg appliance forces produced from anchor bends, wire design, bracket contact, and elastic pressures. Properly designed, the differential system permits effective posterior anchorage stability with light, rapid tipping and intrusion of anterior teeth. The predictability of many tooth movements may be due to the direct influence of the forces of physiology that are an effective part of the true differential system. Several past clinical studies have documented the capability and predictability of the Begg system to produce consistent treatment changes. 8, 11, 12,25-31 Clinicians familiar with the Begg system recognize their ability to open bites, retract incisors, torque incisors, and upright roots (Figs. 1.4, 1B, and 1 C). It is also significant that the maximum flexibility of the appliance and the greatest degree of tooth movement occur in the early stages of treatment. These stages-Stages I and B-are the periods of treatment in which differential force is critical, tooth movements are very rapid, and the physiology of freeway and functional occlusion are of paramount importance in establishing maximum posterior anchorage. 32-35Personal observations and discussions with other Begg clinicians have frequently confirmed the fact that the mechanics in Stage I and Stage II are the keys to success in Begg treatment, since they determine the effective bite opening, the optimum anteroposterior positioning of incisors, and stability of the molars.
Vol!me 79 Number 6
Begg
and
straight
wire
595
Fig. 3. Frequently after Stage III additional movements are needed to establish optimal finished occlusion. These include such movements as establishing overbite (A), getting proper molar occlusion (B), setting even torque (C), and correcting undesirable incisor drift (D).
It must be realized at this point that these favorable characteristics of Begg treatment occur in the early periods of treatment, during unraveling, bite opening, and anterior retraction, when physiologic tipping of teeth is desired and most effective (Fig. 2). Little has been said about the Begg appliance in the finishing stages. Probably the most difficult part of Begg treatment is the finishing period, and this problem area has been
Am. J. Orthud. June 1981
595 Thompson A.
B.
Favorable characteristics of Begg appliances 1. Rapid bite opening 2. Rapid anterior alignment 3. Retraction of six anteriors en masse 4. Supportive extraoral anchorage not recommended routinely 5. Anterior root torque is unlimited by bracket 6. Predictable molar and incisor positioning Favorable characteristics of straight wire appliances 1. Precision arch coordination is routine 2. Precision intercuspation is routine 3. Buccolingual root torque is routine 4. Simplified finishing wires are routine 5. Minimal wire adjustments in finishing
Fig.
4. Begg
and straight
wire
appliances
Unfavorable characteristics 1. Posterior root torque is difficult 2. Three-dimensional arch coordination is difficult 3. Maintaining rotations is difficult 4. Finishing intricacies are difficult 5. Maintaining uprighting and torque is difficult
Unfavorable characteristics 1. Rigid appliance due to interbracket distance 2. More friction with sliding mechanics 3. Additional supportive anchorage recommended 4. Segmental retraction of anterior teeth 5. Forward tipping of incisors in continuous wire leveling 6. Prolonged bite-opening mechanics have
distinctly
different
characteristics
addressed before.“6 Control of buccolingual torque on posterior teeth is difficult in the Begg system and requires special auxiliaries to achieve good occlusal position. The ease of tipping on the single-point contact tends to permit undesirable tooth movements during the finishing periods. These movements can be produced by occlusal forces, functional interferences, damaged or bent arch wires, habits, and other minute, extraneous forces. The forces are capable of opening spaces, tipping teeth, and generally producing undesirable movements which frequently require additional appointments and adjustment procedures to obtain the optimum occlusal finish. Stage IV movements in Begg treatment are, theoretically, those added adjustments which are needed to obtain the optimum finish to the occlusion.:s6 It should be noted here that these precise finishing movements are late treatment procedures and are distinctly different from the rapid, gross changes achieved so effectively by Begg technique at the beginning of treatment (Fig. 3). Appliances of the straight wire type appear to have some distinct advantages over the Begg system at certain points of treatment.22x 3i, 38 These are principally related to the precision type of bracket and arch wire design. The wider twin bracket with the shorter interbracket distance used in some systems increases the rigidity of the continuous straight wire. It tends to increase the forces applied interdentally, increases the friction, and places positive three-dimensional forces and couples on the teeth. The rigidity of the straight wire, although having the potential of a more precise appliance with closer tolerance or fitting, has certain mechanical disadvantages in early alignment and leveling procedures. The inflexibility and friction of the appliance are magnified in the initial arch wire sizes because of the significantly greater angular position of the slots produced by the malposi-
Volume 79 Number 6
Begg
Fig.
5. Four
brackets
are designed
to accommodate
all teeth
and
except
straight
wire
597
molars.
tion and tipped teeth in the original malocclusion. The continuous leveling arch wires in the greatly angulated straight wire slot sequence set up extraneous forces among the teeth which tend to produce leveling by forward movement of anterior teeth.3g Unlike the single-point Begg bracket, the teeth cannot tip freely into extraction sites, and the typical intrusion and lingual tipping of incisors seen in the Begg treatment are not evident. In addition, anchorage support from an extraoral or intraoral appliance is frequently recommended to control the diversified forces generated in the irregular-slot brackets as alignment or retraction of teeth is performed. Bite opening in conventional straight wire mechanics is not as rapid as it is in the Begg system, where bite opening is effectively undertaken early in treatment by molar elevation and incisor intrusion which occur simultaneously with the en masse retraction of incisors. In spite of the apparent difficulties that can arise during the early periods of treatment with the straight wire appliance, it has been shown to produce fine precision and quality of occlusion in the finishing of treatment. 13, 22 The ability to place teeth closer to proper occlusal position with preangulated and pretorqued brackets with less arch wire manipulation is a definite treatment advantage. The heavier forces produced over shorter interbracket distances with precisely fitting rectangular wires in a rectangular slot establish excellent positive control in three dimensions, provide precise movements, and eliminate the undesirable tipping frequently seen during finishing procedures in a Begg system. In addition, the three-dimensional capability of the rectangular wire does provide a more accurate means of achieving total coordination of arch wires in both arches to provide optimum occlusal intercuspation. In this overview of Begg and continuous straight-wire appliances it appears that advantages and disadvantages of each system are due to the inherent characteristics in the
598
Am. J. Owhod.
Thorrpson
Junr
1981
compensation
Fig. 6. Straight Angulation.
wire
control
is designed
into
the
brackets.
A, Torque.
B, Input
compensation.
C,
design of the two systems. Each is constructed to perform one function best-Begg to produce gross movements rapidly with tipping, straight-wire to perform precise bodily movement over shorter distances in a force system of a more static nature. The Begg system is rapid in early treatment but becomes more cumbersome in the finishing stages. The straight wire system is prone to complications in early periods of treatment but is efficient in the final finishing adjustments (Fig 4).
Volume 19 Number 6
Begg
and
straight
wire
599
/ All upper brackets
Lower 2nd bicuspid brackets
Lower cuspid through 1st bicuspid brackets
Lower anterior brackets
Fig. 7. Each four-stage bracket is indexed for easy identification. (Identification distal-occlusal.) On Dyna-Bond II foil/mesh bonding bases, a red dot for maxillary mandibular brackets is on the distal-gingival corner of the base for all assemblies upper premolar and lower second premolar can be identified by a colored dot aspect of the base and on the chimney of the bracket where the lock pin enters. have no marking at all.
marks and through on the Lower
are toward the a black dot for canines. The distal-gingival first premolars
An appliance design that captures the advantages of both systems and reduces the disadvantages of both is the topic of discussion in the remaining part of this article. A new bracket concept and a treatment approach will be described. The new appliance enables the orthodontist to combine both the tipping and bodily movement principles of mechanics. The system permits the use of pure Begg mechanics in that part of treatment and in those cases in which it is most effective. It also permits the use of a straight wire appliance in the same cases or in any cases in which a rigid, preangular-pretorqued finishing procedure is desired. The dual capability of the appliance system is due to a combination bracket design* in which the lower third of the bracket is a Type 256 Begg bracket and the upper two-thirds of the bracket is a 0.018 by 0.025 inch straight wire slot with in-and-out positioning, preangulated and pretorqued (Figs. 5, 6, and 7). The Begg slot will accept all auxiliaries and arch wires used in Begg treatment and it performs as a typical Begg bracket in relation to tipping, bite opening, incisor and molar positioning, and torque. The appliance is set up in the standard manner with the 0.036 inch Begg tube placed gingivally on the first molars. All Begg slot heights, other than the molars, are dictated by the edgewise slot and, as such, are 1 to 1.5 mm. more gingival *Experimental and 7).
design
and research
development
performed
by Unitek
Corporation,
Monrovia,
Calif.
(Figs.
5,6,
Am
BRACKET
“‘,CANlNES ---UPPER Fig.
POSITIONING
4 to 4+mm LATERALS 8A. Bracket
J. Onhod. June 19x1
3mm
positioning
and
angulation.
than in a routine Begg banding. It is absolutely essential to set up the straight wire slot so that on the straight wire series the wire is level from the molar tube to all other brackets. In clinical preparation, it is desirable to band the molars first. Slight variations in the dimension from molar tube to cusp tip will exist because of anatomic differences, but a cusptip-to-tube distance of 3.5 mm. is a desirable starting point. If 3.5 mm. is acceptable, then all other edgewise slots must also be at 3.5 mm. except those on the canines and lateral incisors. Upper and lower canine brackets are placed gingivally 0.5 to 1 mm. more, depending on tooth size and shape. Such a position promotes canine-protected occlusion. The upper lateral incisors are placed 0.5 mm. more incisally to free them from interferences on the working occlusal movements. Each tooth must receive the specific brackets designed for it so that angulation, torque, and the in/out compensation are correct (Figs. 8A and 8B). The 1 to 1.5 mm. increased gingival positioning of the Begg slot does not seem to affect the bite-opening or tipping characteristics of Begg treatment. Free tipping is made very effective by means of a specially tapered bracket slot (Fig. 9). Also, special bypass pins and safety lock pins are available to reduce binding. The pins used are of a special length, since the width of some of the combination brackets is larger than a routine 256 bracket. The pin length is slightly greater in order to clear the tie wings of the edgewise part of the bracket, especially on the maxillary incisors. Begg molar tubes are kept gingivally and can be obtained with convertible straight wire tubes on the lower molar. The convertible tubes provide for desired Class II elastic hooks during Stages I, II, and III. They can be adapted to function as a routine straight
Volume 79 Number 6
Begg
IV
STAGE -10”
-10”
Fig.
9. Tipping
is possible
8B.
because
straight
wire
601
TORQUE -7”
-70
(-1 Fig.
and
Four-stage
Lab.
-7”+3O
root
c7”
torque
torque.
of the tapered
slot in the Begg
bracket.
wire type of bracket when the straight wire system is continued with first and second molars. It is not recommended that second molars be incorporated into the Begg system initially. All Begg treatment should be built around the first molar as the anchor unit, since experience shows that this is the most effective differential anchorage position and the most desirable for bite-opening mechanics of the Begg philosophy. After the bite is opened and retraction of incisors has been completed, the second molars can be banded without altering the anchorage or bite-opening potential of the system. When the appliance is properly and accurately constructed, the system is set up so that
602
Thompson
Am. J. Orthod. June 1981
Fig. 10. The combination four-stage appliance effectively controls the routine Stages I, II, and III of pure Begg mechanics and can then be transformed into a pure straight wire appliance by using the preadjusted edgewise slots. A, Before treatment. 6, Stage I. C, Stage II.
all edgewise slots are positioned for accepting a straight arch wire. The angulation, tip, and torque are comparable to current straight wire systems. Ligation of the wire can be done routinely with ligature wire or elastic modules. The lower molar combination tube permits ease of passing from first to second molars. Headgear tubes are available if desired. Use of the edgewise portion of the bracket is not begun in most instances until late in Stage III. Clinical experience with the combination bracket indicates that the Begg portion of the bracket is highly successful and fulfills all the essentials of a true 256 type slot. The treatment procedures necessitate the use of pure Begg type principles when the Begg slot is being used. All arch wire forms, anchor bands, bypass bends, and elastic forces should be similar to a routine Begg treatment approach. I*, N* 30 Because of the difference in the physical characteristics of the bracket parts, any attempt to alter the Begg treatment principles by switching slots or forces is prone to problems and anchorage difficulty. All Stage I, II, and III objectives should be followed, and this can be done effectively only if free tipping is exercised within the Begg slot (Fig. 10). It is recommended that treatment be initiated with routine 0.016 inch round Australian wire (orange special plus) using 40- to 45-degree anchor bends and 2% to 3 ounce Class II elastics. Vertical loop arches are still suggested as the initial wire if gross irregularity exists and bite opening is desired immediately. A free-tipping appliance is essential, and all recorded problems which can affect tipping and bite opening must be controlled. “, 32*” For the best physiologic response to the appliance, the Begg procedures should be carried completely through Stage I and Stage II and at least partly through Stage III. Routine 0.016, 0.018, and 0.020 inch round wires, toe in or out, anchor bends, and intra- and interarch elastics are used as recommended in Begg therapy.
Volume 79 Number 6
Fig. 10 (Cont’d). (0.018 by 0.025
Begg and straight wire 603
D, Pre-Stage III. E, Stage Ill. F, Stage inch nitinol). H, Band removal.
IV (braided
rectangular
wire).
G, Stage
IV
At the end of Stage II, the occlusion should show the typical Stage II characteristics: spaces closed, bite opened to an edge-to-edge relationship, molars Class I or better, incisors retracted and tipped lingually, all rotations and ectopically repositioned teeth overcorrected. Stage III is essential; the combination bracket is not intended as a substitute for this phase of treatment. When the occlusal relationship and treatment objectives are ready for Stage III, the severe tipping of the buccal segments and incisors, which is typical and characteristic of Begg therapy, produces a very irregular pattern to the angulated rectangular slots. The angulation is so severe in some cases that placement of leveling wires is contraindicated (Figs. 1IA and 1 lL?). Short interbracket distance between the edgewise slots increases force values and leveling forces. A common difficulty is the tipping of teeth mesially into a more bimaxillary relationship as seen in routine edgewise leveling procedures with full appliancing and no elastics or coil springs.40 The unwanted movement can
604
Am. J. Orthod. June 1981
Thompson
Fig. 11A. Angulation of the edgewise slot at the beginning of Stage III contraindicates placement of the main arch wire in this slot. Routine Stage Ill movements must be used until a straight arch wire can be inserted with the least number of extraneous leveling forces and with a reduced amount of force. An angulation of 5 to 7 degrees seems adequate.
STAGE III 3o”to40~
------
ZT?cF 0 0= -------_‘c----..-s -- -- ---HOR. Fig.
118.
be eliminated by undertaking adequate uprighting in Stage III to level the straight wire slots before a straight wire is placed (Fig. 12). Stage III should be carried out with 0.020 inch base wires, constricted in the maxillary arch, and having reduced anchor bends in a typical Begg program. All Begg uprighting springs and torquing auxiliaries can be placed in the Begg slot with no difficulty. The Stage III mechanics should be continued until the occlusion approaches a fairly level plane and the edgewise slots are almost parallel. This is a subjective decision by the orthodontist, but clinically it seems to be within 5 degrees of the horizontal. When the alignment has reached this degree of leveling and uprighting, the Begg portion of treatment has ceased. The Begg wires and springs are removed and the remaining treatment is done in the rectangular slot with a straight arch wire. The new wires may be braided round, braided rectangular, nitinol, routine round, or edgewise wires up to 0.018 by 0.025 inch. Usually one braided or small round wire series is needed before a rectangular wire can be placed for final torque control. Some cases will require adjustments in the final rectangular wire to maintain proper anterior incisor torque. Since Begg treatment has excellent torquing capability and the degree of torque is dependent on the clinician’s decision, the predetermined amount of torque in the straight wire slot may be inadequate to meet the degree of torque established
Volum<~ 79 6
Number
Begg
und
straight
wire
605
Fig. 12. The unique advantages of Begg treatment can best be accomplished by use of routine Begg tipping mechanics. Maximum anchorage control and minimum forward movement of incisors necessitate adherence to these mechanical principles until a straight wire can be inserted without adverse effect. Generally, a braided steel wire or a 0.016 inch round or square nitinol wire can be inserted when the uprighting has leveled the rectangular slots to within 5 to 7 degrees of the level occlusal plane. A, Before treatment. B, Stage I. C, Stage II.
in Stage III by the orthodontist. If the standard 7-degree torque is thought to be inadequate to meet the clinician’s needs, the torque for the incisors can be obtained in increased amounts as in other systems. We feel that banding of lower second molars is contraindicated by early Begg treatment because of the philosophy of mechanics involved in bite opening. Second molars are not used for anchorage or bite opening, and their use can even interfere with these functions because of the more distal placement of vertical forces and the reduction of the vertical extrusive component of the Class II elastics. Banding of second molars is, however, often essential for proper marginal ridge control, to improve the buccolingual position of the second molars, and to act in functional balance. These movements are best accomplished in late Stage III and with the rectangular straight wire mechanics. The second molars can be banded or bonded during Stage IV, and sectional 0.014, 0.016, or 0.018 inch wires can be used to begin leveling without interfering with Stage III. The second molars can be bonded or banded with routine straight wire tubes placed at the same occlusogingival positions as the first molar rectangular tube. Since the Stage III arches are in the round tube, the sectional auxiliary wires to level the second molars can be placed in the rectangular tubes. When the Stage III is removed and straight wire treatment initiated, the second molars are level and ready for incorporation into the finishing mechanics (Fig. 13). Some criticism of the rigid finishing procedures has come forth from a few Begg clinicians and others.22. 37, ax S ome believe that loose, free-tipping appliances are more
606
Thompson
Am. J. Orthod. Jurw 1981
Fig. 12 (Cont’d). D, Stage III. E, Stage IV (0.016 inch round wires). F, Stage IV (0.018 inch round and 0.016 by 0.025 inch lower). G, Stage IV (0.018 by 0.025 inch wires). H, Band removal.
upper
desirable to encourage physiologic or functional settling of occlusion. The idea of a functional occlusal settling is good, but the rectangular finishing rigidity does not alter this concept. Optimum occlusal settling is possible only if the teeth are in their best threedimensional position and in best relation to the functional paths. These are established most accurately with proper torque, uprighting, and arch form. When this is accomplished in the straight wire segment of the bracket, any finishing or band-removal technique is enhanced. Segmental band removal, positioners, or light 0.012 inch functional settling wires are all effective. Ideal finishing is completely dependent upon the best achievement of the Stage I, II, and III goals where the physiologic harmony of Begg treatment is produced. These stage objectives are designed to complement the tipping movements, force vectors, and force values of the appliance to use freeway space and molar elevation,
Volume 19 Number 6
Begg
STAGE
STAGE
Fig.
13. Second-molar
and
straight
wire
607
III
Ip
control.
to retract incisors into a proper functional environment, and to establish the optimum anteroposterior position of the denture.““, 30, 31 We have observed additional favorable findings in the clinical application of the combination system. Changes in the amount of time required to accomplish specific stage objectives can vary when compared to traditional Begg treatment. Stage III can be altered because of the shortening of the usual uprighting periods by finishing the uprighting and torque in the rectangular slot. In Class I extraction cases, where Stage II closure may be minimal and uprighting of canines frequently amounting to only a few degrees, Stage III may be completely eliminated and only rectangular finishing may be needed. Use of the edgewise slot in one arch and the Begg slot in another arch provides the clinician with different anchorage and movement combinations where bodily movement and free tipping can be employed simultaneously. It is also possible to reduce looped arches in Stage I by using sectional auxiliary arch wires, such as flexible twisted wire or nitinol leveling wires, in the edgewise slot on the four incisors to initiate alignment while the Begg base arch is used to obtain bite opening and retraction of canines and incisors. In nonextraction cases, Stage II and Stage III may be significantly shorter and possibly nonexistent because space closure in Stage II is usually minimal, uprighting is needed only on certain individual teeth, and torque requirements are reduced. It is often possible to enter the rectangular slot with the main wire very early in the nonextraction cases and to control most of the uprighting and torque with only the straight wire type of angulated and torqued slot. Another advantage of the combination system bracket is the potential in transfer of cases under treatment. Routine transfer of Begg cases to a few areas of the country is difficult because of the lack of treatment facilities and the scarcity of clinicians who have had experience with the technique. Frequently, patients are required to travel longer distances or to have appliances changed in order to continue treatment. In a combination system, an orthodontist can switch to a slot he feels best able to control. An astute edgewise clinician can go to the rectangular slot and, using appropriate anchorage design, sectional wires, etc., continue treatment with minimal inconvenience to the patient or the doctor. Clinical use of the combination Begg and straight-wire type of appliance has been very
608
Thotnpsor~
gratifying. The optimum treatment capabilities of two excellent treatment approaches are united in a common technique. The combination bracket appears to have good potential for clinical orthodontics. Much can be expected in new designs and combinations as the idea progresses. This article has been presented to familiarize clinicians with the principle. Perhaps it will stimulate
others
to seek
improvements
in design
and
techniques.
1 acknowledge, with thanks, The University of Florida Department of Orthodontics and Mr. Conrad Bamgrover and Mr. George Augur of Unitek Corporation for their assistance in obtaining some of the line drawings for this paper. I also thank Dr. William Baker for his assistance in the development of the combination bracket concept REFERENCES 1. Brodie, A. C., and Thompson, J. R.: Factors on the position ofthe mandible, J. Am. Dent. Assoc. 29: 925, 1942. 2. Aubrey, R. B.: Occlusal objectives in orthodontics, AM. J. ORTHOD. 74: 162-175. 1978. 3. Ingerwall, Ben@: Functionally optimal occlusion, the goal of orthodontic treatment, AM. J. ORTHOD. 70: X0-90, 1976. 4. McHorris, W. H.: Occlusion with particular emphasis on the functional and parafunctional role of anterior teeth. Part I. J. Clin. Orthod. 13: 689-701, 1979. 5. McHorris, W. H.: Occlusion with particular emphasis on the functional and parafunctional role of anterior teeth. Part II, J. Clin. Orthod. 13: 608-620, 1979. 6. Parker, W. S.: Centric relation and centric occlusion-An orthodontic responsibility, AM. J. ORTHOD. 74: 481-500, 1978. 7. Roth, R. H.: Temporomandibular joint pain-Dysfunction and occlusal relationships, Angle Orthod. 43: 136-153, 1973. 8. Weber, F. N.: Clinical investigations related to the rise of the Begg technique at the University of Tennessee, AM. J. ORTHOD. 59: 24-36, 1971. 9. Williamson, E. H., Caves. S. A., Edenfield, R. .I., and Morse, P. K.: Cephalometric analysis: Comparisons between maximum intercuspation and centric relation, AM. J. ORTHOD. 74: 672-6?7, 1978. 10. Andrews, L. F.: The straight wire appliance, origin, controversy, commentary, J. Clin. Orthod. 10: 99-l 14, 1976. II. Barrer, H. G.: A survey of Begg treatment, AM. J. ORTHO~X 40: 494-506, 1963. 12. Begg, P. R., and Kessling. P. C.: Begg orthodontic theory and technique, ed. 3, Philadelphia, 1977, W. B. Saunders Company. 13. Magnus. B. W.: The straight wire concept, AM. J. ORTHOD. 73: 541-550, 1978. 14. Mulligan, T. F.: Common sense mechanics, J. Clin. Orthod. 13: 588-594, 1979. 15. Mulligan, T. F.: Common sense mechanics. Part II, J. Clin. Orthod. 13: 676-683, 1979. 16. Ricketts, R. M.: Bioprogressive therapy as an answer to orthodontic needs. Part I, AM. J. ORTHOD. 70: 241-268, 1976. 17. Ricketts. R. M.: Bioprogressive therapy as an answer to orthodontic needs. Part II, AM. J. ORTHOD. 70: 359-397, 1976. 18. Sims, M. S.: Conceptual orthodontics, AM. J. ORTHOD. 71: 431-439, 1977. 19. Thurow, R. C.: Edgewise orthodontics, ed. 3, St. Louis, 1972, The C. V. Mosby Company. 20. Andrews, L. F.: The six keys to occlusion, AM. J. ORTHOD. 62: 269-309, 1972. 21. Andrews. L. F.: The straight wire appliance, Syllabus of philosophy and technique, 1975, L. F. Andrews. 22. Meyer, M. M., and Nelson, G.: Preadjusted edgewise appliances: Theory and practice. AM. J. ORTHOD. 73: 485-498, 1978. 23. Begg, P. R.: Light arch wire technique employing the principles of differential force, AM. J. ORTHOD. 47: 30-48, 1961. 24. Begg, P. R.: The differential force method of orthodontic treatment, AM. J. ORTHOD. 71: l-39, 1977. 25. Barrer, H. G.: Evaluation of the Begg technique 5 years later, Begg J. Orthod. Theory Treat. 3: 29-34, 1964.
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26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41, 42. 43.
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Barton, J. A.: A cephalometric appraisal of cases treated with edgewise and Begg technique, Angle Orthod. 43: 119-126, 1973. Daugremond, Chester: The Begg light wire treatment; a comparative study. Unpublished data, 1969. Parker, W. S.: A consideration of the pure Begg technique, Angle Orthod. 39: l-10, 1967. Swain, B. F.. and Ackerman, J. L.: An evaluation of the Begg technique, AM. J. ORTHOD. 55: 668-687, 1969. Thompson, W. J.: A cephalometric appraisal of incisor positioning with the Begg appliance, Angle Orthod. 44: 171-177, 1974. Thompson, W. J.: Occlusal plane and overbite, Angle Orthod. 49: 47-55, 1979. Barrer, H. G.: Treatment problems, source and elimination, Begg J. Clin. Orthod. Theory 4: 59-64, 1968. McDowell, C. W.: Static anchorage in the Begg technique, Angle Orthod. 39: 162-170, 1969. McDowell, C. W.: A reappraisal of cephalometrics. Part I, J. Clin. Orthod. 4: 82-92, 1970. McDowell, C. W.: A reappraisal of cephalometrics. Part II, J. Clin. Otthod. 4: 134-145, 1970. Thompson, W. J.: Begg Stage IV, Begg J. Orthod. Theory Treat. 5: 17-24, 1969. Begg, P. R.: Personal communication, January, 1980. Dellinger, E. L.: A scientific assessment of the straight wire appliance, AM. J. ORTHOD. 73: 290-299, 1978. Baldridge, Doyle: Leveling the curve of Spee: Its effect on mandibular arch length, J. Pratt. Orthod. 3: 26-41, 1968. Begg. P. R.: Choice of bracket for the light wire technique, Begg J. Orthod. Theory Treat. 1: 1 I-18, 1962. Thompson, W. J.: Current application of Begg mechanics, AM. J. ORTHOD. 62: 245-271, 1972. Williamson, E. H.: Occlusion: Understanding or misunderstanding, AM. J. ORTHOD. 46: 86-93, 1976. Timm, T. A.. Herremans, E. L., and Osh, M. A.: Occlusion and orthodontics, AM. J. ORTHOD. 70: 138-145. 1976.