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The Begg light-wire treatment: A comparative study
The Begg light-wire treatment: A comparative study Theodore M. Warren, Pa.
I
Kottrabu,
D.D.S.,
M.S.
n 1954 the first of a series of articles that led to a new treatment philosophy was presented by P. Raymond Begg.l His accompanying technique stressed the use of light round wires and differential force in orthodontic treatment, and it has influenced the thinking of orthodontists throughout the world. The use of light wires is not an entirely new concept. The Johnson twin-arch appliance, as introduced in 1931, was the first to recognize the advantages of light resilient round wires, but the principal influence in the past decade has come from Dr. Begg. In the beginning, his concept of occlusion was at variance with the accepted view in orthodontics. Correct occlusion, according to Begg, is not a static condition ; in fact, the only constant in correct occlusion is continual change. Throughout life, teeth continually migrate in two directions-horizontally (mesial migration) and vertically (continual eruption). This concept of normal occlusion was developed after a thorough study of skulls of the Australian aborigine. The two major factors to be considered in producing anatomically correct occlusion in the Australian aborigine are tooth migration and attritional tooth wear. Begg contends that attritional occlusion involves a wearing away of tooth cusps, a reduction in arch length, and establishment of an end-to-end incisor bite ; it explains Angle’s Class III occlusal relationship, it results in the only anatomically correct occlusion, and it has the constant quality of continuous change throughout life. Conversely, Begg contends that the SOcalled textbook normal occlusion, with the teeth almost unworn throughout life (both occlusally and interproximally) and with high interlocking cusps and a moderate to deep overbite, is anatomically abnormal. One skull shown by Begg illustrates tooth attrition in which the lower first molar is worn down to the cementoenamel junction. He estimates that, on the average, there is an approximate mandibular arch reduction of 14.7 mm. This gives him the basis for the etiology of crowding and third molar 386
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Number
Begg light-wire treatment
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impactions ; hence, the rationale in certain cases. History
for
extracting
four
for
his technique
and even eight
387 teeth
of the appliance
Begg2 makes certain claims In his 1956 article he wrote:
that
seem to be valid.
All required tooth movements-bodily, torquing, and tipping-can be performed with this technique . . . . the use of thin round steel arch wire raises the standard of results, as it eliminates the excessively high forces that are exerted by rectangular arch wire. Active treatment time is greatly reduced. . . , Nevertheless, it is a fortunate coincidence that the orthodontic force values that are used cause least discomfort to patients, least loosening of teeth, and least damage to tooth-investing tissues, while at the same time they are also the forces that move teeth the most rapidly and are the most easily controlled forces.
Begg spent more than 20 years in the development of his technique, beginning a few years after he attended the Angle course in Pasadena :from March, 1924, to November, 1925. Following his completion of the course, he returned to Adelaide and practiced orthodontics with the edgewise mechanism. Through trial and error, he evolved a system of .tipping and uprighting rather than bodily movement for the positioning of .teeth. The principle of individualized tooth control-a cardinal feature of the edgewise appliance-is neither sacrificed nor contradicted with the use of light resilient’wires in the modified ribbon brackets that Begg developed for his treatment procedure. Other chief improvements are the extremely efficient sectional torquing arches, uprighting springs, lingual buttons, and the realization that, with this method, it takes just as long to finish treatment according to acceptable standards as with any other technique. Differential
force
The principle8 of differential force can be applied by an orthodontist with the light-wire mechanism because he has the option of either tipping the teeth or moving them bodily. Storey and SmithI’ explored the possibility of finding an optimum force in their study of tooth movement. They used the edgewise appliance for experiments with spring forces of varying values to move canines distally. First permanent molars, together with second premolars, were used as anchorage for the springs to move the canines into the premolar extraction spaces. Their findings show that similar behavior of the teeth occurred in all cases studied. They found that there is an optimum range of force values to produce a maximum rate of movement of the canine. This force range for moving a canine distally is between 150 and 200 Gm. Mesial movement of the molar-premolar anchor unit occurred in the high range of force values, 300 to 500 Gm. When the force was below 150 Gm. for the canine and below 300 Gm. for the anchor teeth, neither moved appreciably. Begg2 found that the light force value advocated by Storey and Smith (or slightly less) was optimum for moving a canine ; he found also that this
388
Kottraba
force need not bc incrcascd proportiona.lly, and perhaps not at ail, for t.he simultaneous backward movement of the six anterior teeth in order to close the first premolar extraction spaces. The YOWC~S found by Storey and Smith to be the most favorable for tooth movement from the standpoint of rapidity and tissue tolerance a.re much lower t,han those exerted by the edgewise arch wire. Halderson and associates7 state t,hat in many instances the force exerted by an edgewise arch wire is of the .very high value of ovel 2 pounds, or approximately 900 Gm., which causes a pathogenic tissue response. Steiner,16 in considering the question of arch wire force, states that any tooth movement might be accomplished with just one a.djustment if the arch wire were to be reduced sufficiently in size. He also says that this has been proved by all who have used the 0.018 inch or even the 0.022 inch round steel arch wires in competition with heavier forces. He states that the edgewise appliance principles may someday be applied by using an arch wire of an extremely elastic metal with a diameter that may be only a small fraction of the cross section of the present one. Steiner also points out that, to gain much tooth movement, whether it be rot.ation torquing or mesial or distal tipping, a great deal of force must be applied to distort the short rigid section of the edgewise arch wire enough to accomplish power delivery. Clinicians7 using t,he edgewise mechanism have learned to start their treatment with a series of light round wires. This is sound treatment for two reasons: (1) it takes advantage of tipping movements and (2) it utilizes forces that are much lighter than is standard with an edgewise wire. Begg” felt that this statement implied a need for an appliance that will deliver a sufficiently light force and, at the same time, accomplish universal tooth movement throughout treatment. Reitan13 advocates the use of light continuous forces, but he is strongly opposed to a tipping movement since, because of the mechanical principles involved, the forces create compressed cell-free areas in the periodontal membrane more frequently than those created in a bodily movement. Jarabakg states that some clinicians advocate the tipping of crowns into their desired positions in the arch and the later uprighting of their roots. These uprighting mechanics are accomplished with long-moment arm levers fashioned as auxiliary spring loops. darabak is strongly opposed to this type of movement because of the damage to alveolar bone and resorption of roots. He demonstrates this by means of serial radiographs. The three
stages
in the
Begg
technique
In a recent interview,5 Begg stated that there are no basic mod&ations of the technique since the publication of his article entitled “Light Wire Technique. ’‘3 The light round arch wire differential force treatment technique is divided into three separate and distinct stages that must not be allowed to overlap. The following conditions are overeorrected during the first stage of treatment: crowding, anterior spaces, rotations, deep anterior
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treatment
389
overbites, anterior open-bites, anteroposterior discrepancies, arch contour and coordination, and all cross-bites. In the second stage of treatment all overcorrections are maintained and any remaining extraction spaces are closed. In the third and final stage the axial relations of all upper and lower teeth are corrected simultaneously.4 Cephalometric
analysis
The literature contains many applications of cephalometric analysis to evaluate the results achieved by the Begg technique. If the differential force theory is to be substantiated, then anchorage control must be demonstrated. Williamslg found that it is significant, with the Begg treatment, that the in&al edge of the lower incisors reaches a final position quite close to the A-P line-a critical position if upper and lower lip balance is to be achieved. He found that the major expenditure of anchorage occurs during the third stage and that this must be anticipated in treatment calculations. Grafton found that, in the treatment of Class I malocclusion, 47.5 per cent of the maxillary extraction space and 51 per cent of the mandibular extraction space beyond that required for alignment of the teeth is closed by forward movement of the anchor teeth. In the treatment of Class II, Division 1 malocclusion, 23 per cent of the maxillary extraction space and 97.2 per cent of the mandibular extraction space is closed by forward movement of the anchor teeth. Correction of the molar relationship is accomplished mainly by the forward movement of the mandibular first molars. PerlowlL believes that Class II elastics are contraindicated in patients described by Schudy14 to be hyperdivergent, and he therefore believes that the Begg technique cannot be used. Schudy designates a steep mandibular plane as being hyperdivergent and a flat plane as being hypodivergent. On the other hand, Perlow considers Begg treatment ideal for the hypodivergent types. He also states that the treatment of mature patients by means of unlimited tipping and countertipping is open to serious questions. Williams1g states that, in general, without treatment, the flatter the mandibular plane, the greater the tendency for it to become even flatter during the growth period. The steeper the mandibular plane, the less intense is its tendency to flatten during the growth period. Pure Begg treatment instituted during the growth period may inhibit the flattening process and temporarily countermand it. However, if there is a growth period following treatment, the flattening process will reassert itself and temporary inhibitory effects of treatment may be more than totally compensated for, depending on the magnitude and duration of the posttreatment growth phase. James8 concurs and shows that the Frankfort-mandibular plane angle increases slightly during treatment but decreases during a 2-year posttreatment period. Nor is the vertical height of the upper incisor changed by any significant amount. Deep overbite is corrected by elevation of the lower molar and depression of the lower incisors. After 2 years, there is approximately a 51 per cent return of the overbite.
390 Kottraba
A
C
Fig. 1. Attachments used in Begg light-wire treatment. A, Doubled-back arch wire ends are inserted in oval tube on second molar. They are used when first molars have been extracted. B, Lingual button with elastic ligature for rotation. C, Lingual buttons for maintaining closure of extraction spaces. D, An “udder’” arch to support mandibular anchorage. (No reference in text.)
Williamsls also states that the pure Begg technique is effective in the vertical control of the upper incisors. Kimmonsl” reports no significant change in the measurement from the palatal plane to the tip of the upper incisors during Begg treatment. He also found an improvement in the maxillary and mandibular apical base relationship a,s a result of the posterior movement of point A. Pridemore l2 found that the mean reduction of the ANB angle in twenty-one patients was 3.07 degrees a.nd that this was accomplished primarily by the posterior movement of point A. Begg
treatment
procedures
The following is a description of the Begg technique as currently applied. In a four-tooth extraction case, all of the teeth from the first molars forward are banded. All but the molar bands receive a ribbon type of bracket, and a buccal tube is placed on the molars parallel to the occlusal plane. If the first molars are extracted, oval tubes are placed on the second molars, which receive a doubled-back arch wire (Pig. 1). Lingual buttons, which are used for rotation and for maintaining the closure of the extraction spaces during the
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391
Fig. 2. Various 0.016 inch looped initial arch wires. Note the molar anchor bands, bypassed premolar brackets, and Class II elastics that are usedin the first stage of treatment.
third stage, are placed on the lingual aspect of the molars, premolars, and canines. The initial arch wire for Stage I is 0.016 inch in diameter. It is either fabricated directly at the chair or indirectly from a previously measured chart, starting at the left buccal tube and placing intermaxillary hooks just mesial to the canine brackets. Vertical loops are placed at each broken contact for irregular teeth (Fig. 2). When the wire is passive, the intermaxillary hooks lie distal to the canine brackets, so that when the wire is pinned a compressive force will reciprocally drive the canines distally. If there are anterior spaces, the intermaxillary hooks are a few millimeters mesial to the canine brackets to allow closure of the space by a canine-to-canine elastic. Strong anchor bends are placed just mesial to the buccal tubes, approximately at the interproximal space. The premolars are not pinned but are only tied loosely to the arch wire. A Class II intermaxillary elastic with a force range of 2 to 21/ ounces is placed immediately. Cross elastics are used in the event of cross-bites, and elastic ligatures are used to tie rotations. As soon as the irregularities have been overcorrected, the looped arch wire is replaced with an arch wire (with bayonet bends) that will maintain the overcorrected positions of the teeth. The canine intermaxillary hooks are ligated to the distal brackets to prevent
Fig. 3. Start of the second treatment stage. lntramaxillary tion spaces. Stage 1 objectives have been accomplished, relationship.
elastics are used to close extracwith the incisors in an end-to-end
anterior spacing. Treatment continues in this fashion until all of the Stage I objectives have been reached. This ordinarily takes from 3 to 6 months. Usually, the only arch adjustment required in the first stage is in positioning the anchor bend further mesially to prevent its binding in the buccal tube. In the second stage of treatment, the same arch wires are used and intramaxillary elastics are placed in the four posterior quadrants until the extraction spaces are closed (Fig. 3). Class II or Class III elastics are applied as needed. The wire is still not engaged into the premolar bracket in Stage II. In the third stage, the lingual buttons on the molars and canines are ligated with 0.012 inch stainless steel wire (Fig. 4). The maxillary arch is constricted to counteract the resultant force of the auxiliary torquing arch. The main arch is now seated into the premolar brackets and tied into place. Ties are used in place of pins wherever uprighting springs are indicated. The maxillary incisors receive the auxiliary torquing mechanism, and 0.014 inch helical uprighting springs are placed as needed on the premolars, canines, and lateral incisors. Class II intermaxillary force is needed in this stage to maintain an edge-toedge position of the incisor. The length of treatment in Stage III is approximately the same as in the first two stages combined. When the axial relations of
Volume Number
59 4
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393
Fig. 4. Stage 3 mechanics near the end of application, The torquing and uprighting auxiliaries are shown in place to correct the inclinations. The ends of the arch wires are bent over the tubes to help in maintaining extraction space closure. Class II or Class III elastics are worn as needed to maintain an end-to-end relationship of the anterior teeth.
the teeth appear clinically close to being correct, a Panorex film is taken to determine the need for any final positioning. A fourth stage is advised during the final months of treatment (Fig. 5). Finishing arches, 0.018 inch in diameter, are placed to complete and refine positioning and to aid in closing space when the anterior and premolar bands are removed. Retention is routinely carried out with a maxillary Hawley type of retainer and a fixed mandibular canine-to-caninelingual arch. Material
and
methods
A total of thirty-one patients, including six nonextraction patients, treated by the Begg technique were assessedradiographically, cephalometrically, and clinically. Fifty-six per cent of these were classified as having Class I irregularities and 44 per cent as having Class II irregularities. A similar analysis was applied to a sample of twenty casestreated with the edgewise appliance. O f these, 25 per cent had Class I and ‘75 per cent had Class II malocclusions. All of these patients wore cervical extraoral appliances for all or part of their treatment (Table I). For the cephalometric measurements,the S-N line was used for a reference
Fig. 5. Finishing arches, 0.018 inch in diameter, are used in the “fourth” stage to accomplish any necessary final positioning. These same arches are then used to close band spaces during the band-removal procedure.
plane. The following measurements were used: SNA, SNB, ANB, i-SN, l-NA (mm.), l-NA (degrees), i-NB (mm.), i-NB (degrees), i-i, occlusal-SN, G6GNSN, Y axis (to SN) , i-AP (mm.), and I-ANS-PNS (by a perpendicular from ANS-PNS to the 1 incisal). Measurements were taken from the original and final cephalograms, and all differences were recorded. To determine which group suffered the most root resorption and periodontoclasia, the final Panorex film of each patient was attached to a glass wall in one of two unmarked groups, so that all could be viewed simultaneously. Four dentists in general practice were asked to assessthese films. Also compared in the two types of treatment were treatment time, the number of arch wires used, and the number of adjustments made. Since the six nonextraction patients in the Begg group were treated much faster and usually did not require a typical three-stage treatment, their cephalometric measurements were not used for the final averages. Discussion
In several studies comparing treatment techniques, the patient samples came from separate practices. There is a danger here that, instead of the effectiveness of the technique being determined, the ability of the operator may be
Volume Number
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395
A
B
C
D
E
F
Fig. 6. Patient J. F. A, B, and C, Pretreatment photographs of a boy 14 years 5 months of age with a Class II, Division 2 malocclusion. Note the extreme overbite and lack of canine space in the maxilla. The mandibular anterior teeth are 8 mm. behind the A-P line. D, E, and F, Photographs taken 2 years after 23 months of nonextraction treatment with the light-wire appliance. The mandibular anterior teeth are now on the A-P line. The FMA was originally 27 degrees, and it now measures 25 degrees. A maxillary Hawley type of retainer is still worn at night. The Class I relationship of the buccal segments and the correction of the overbite appear to be stable.
evaluated. This study should be more valid becauseall the patients were treated by one operator with similar training and experience in each of the techniques used. Much has appeared in the literature concerning the shorter treatment time that is possible with the Begg method. It was found that edgewise treatment
396
Kottruba
B
D
F
Fig. 7. Patient age
with
a
relationship. anterior after
teeth active
continued Note the
T. A. A, B, and Class
II,
There
is
a
are
2 mm.
light-wire for
reduction paralleling
22
of the
2
ahead
teeth
The
anterior of the
treatment. the
adjacent
Hawley satisfactory to the
premolars type
of
torque
extraction
15 years
segments
and
overjet,
D, E, and
line.
first
of a boy
posterior
overbite
A-P
Four
A maxillary
overbite,
photographs
malocclusion.
moderate
months.
of the
C, Pretreatment
Division
and
F, Photographs were
retainer of the
is now
in
the
II
mandibular
and
worn
of
a Class
taken
removed,
maxillary
4 months
ar’e
only
anterior
4 months treatment at teeth,
night. and
sites.
took an average of 1 month longer. When treatment in either group exceeded 2 years by any great amount, cooperation of the patient was always lacking. On the average, more arch wires were used to treat an edgewise case (14.4) than to complete a Begg case (5.4). Also, more adjustments (9) were required for the edgewisegroup than for the Begg group (4.3). It was shown that Point A was moved nosteriorlv. as exnressed bv the SNA L
*-
+
.
Volume 59 Nuwkber 4
Begg light-wire
treatment
397
Fig. 8. Patient S. M. A, B, and C, Pretreatment photographs of a girl 11 years 3 months OP age with a high mandibular plane angle of 29 degrees and a large ANB angle of 9 degrees. The patient exhibited marginal gingivitis of the maxillary anterior teeth, mostly caused by difficulty in closing the lips and consequent mouth breathing. D, E, and F, Photographs taken 21/z years after treatment with the light-wire appliance, 6 months out of retention. Treatment consisted of the extraction of four first premolars and use of the appliance for 18 months. The ANB angle was reduced to 5 degrees and the FMA closed from 29 degrees to 26 degrees. Note the marked improvement in the gingival tissue.
angle, an average of 0.5O more by edgewise treatment and that this occurred in a few more patients (9 per cent). This difference does not seem great enough to be significant. Point B reacted similarly to treatment with both techniques. The angle ANB was reduced in 30 per cent more patients treated with the ed.gewiseappliance, but again the average difference was only 0.5 degree. Torquing of the maxillary anterior teeth was more effective with the Begg
Patients
in sample
31 (25 extraction;
20 (19 ext,raction j I non. extraction
1
ilxtrxctiotr
Class I
25%
5670
Class II
75%
.14%
25. I
24.::
7.4
Average time
6 non
)
treatment (months)
Maxillary
arches
7.0
48 .+..q 2.5
adjustments
5.8
‘I._ 7 .I
3.2
2.1
arches
Mandibular Maxillary Mandibular
adjustments
Cephalometric
measurememts
Increase
average finish
lkcrease
,
!
Same
Edgewise SNA
(degrees)
1.25 ( 10%)
SNB
(degrees)
ANB
(degrees)
1 ( 10%) 1.8 ( 30%) 96.2
1 SN (degrees), ~NA
(mm.)
1NA TNB
(degrees) (mm.)
iNB
(degrees)
l/l
(degrees)
SN-occlusal
(average
SN-mandibular SN-Y
135.8)
(degrees) (degrees)
axis (degrees)
i palatal
(mm.)
15% 25%
4.3 ( 95%)
1 ‘2
( 5%) ( 10%)
2
( 30%)
2.T5 ( 60%)
6 15.1
( 50%) ( 90%)
6.9 6
( 50%) ( 10%)
4.3
( 85%)
3.7
( 15%,l
1.9
( 70%)
1.X ( 70%) 1.8 (100%)
(mm.)
TAP average finish
3.5 ( 75700) 1.9 ( 65%) 7.7-a( 70%)
Il.:{
( 90%)
.;3 ( 10%) 1
!
15%)
+I
-.. 10% -. 20% 15% --
Begg light-wire SNA
(degrees)
1.3 ( 20%)
1.9 ( 68%)
SNB
(degrees)
1
(24%)
1.6
ANB
(degrees)
9 98
(48%)
1.2 ( 40%)
12% wso w40
5.1
(100%)
_--
12.3
( 80%)
4%
2.3
( 72%)
3.9
( 32%)
20% 8%
1SN (degrees), ~NA ANA
average finish
(mm.) (degrees)
2.75 ( 16%)
TPTB (mm.) iNB l/l
1.5
(degrees) (degrees)
(
8%)
6.2 ( 60%) (average
131)
SN-occlusal (degrees) SN-mandibular (degrees) SN-Y axis (degrees) 1 palatal (mm.)
TAP average finish (mm.)
15.6 5.7 I 1.9
( 64%)
( 76%) ( 84To)
7.2
( 24%)
2.6
( 12%)
52%) 64%)
1.9 1.5
( 24%) ( 20%)
1
(
i (
1.B ( 72%) +1.3
12%)
24~~
16% 33%
Volume Number
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Begg light-wire treatment
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technique, as shown by the l-SN angle average of 98 degrees as compared to 96.2 degrees in edgewise tr&tment. However, since the ideal is 103 degrees, both methods fell short in this study. The ability of both methods to control the elongation of the upper incisors was evaluated by the l-ANS-PNS measurement. It is recognized that the validity of this measurement can be questioned because increased growth and upper incisor inclination can change the reading severely. However, the two groups were selected to have as many of the same characteristics as possible. One hundred per cent of the edgewise patients showed an average increase of 1.8 mm., whereas 12 per cent of the Begg patients showed a 1 mm. decrease and the average increase was 0.2 mm. less. One would have to conclude that the Begg method proved more effective in the vertical control of the upper central incisors. It should be remembered that a high-pull headgear was not used. Retraction of the upper incisors was slightly more effective (0.6 mm.) with the Begg method. This is most interesting when one considers that no extraoral traction was used. The reaction of the lower incisor was similar in both samples, except that the apex was moved further lingually by the Begg method, which, in turn, resulted in a better 1-i angle (average, 131 degrees) and a greater lower incisor CNB angle. The in&al edges of the lower incisors were positioned close to the AP line in both groups (+ 1 mm. in the edgewise group and + 1.3 mm. in the Begg group). The behavior of the occlusal plane was the same for both groups, in that it became steeper. The Begg group averaged an increase of 1 degree more than the edgewise group, however. This was probably due to the elevation of the lower molar by the Class II elastic force. Although there has not been enough time for a postoperative study, other investigators have shown that the increased occlusal-plane cant will flatten later.lg Full control of the vertical dimension during Begg treatment has been questioned because of the Class II elastic force that is used throughout the three treatment stages. The two measurements used to evaluate the rotation of the mandible and the consequent opening of the bite are the mandibular plane to SN angle and the Y axis angle (measured to SN). The findings reveal that, on the average, the mandibular plane angle increased 0.9 degree less for the Begg patients, for 18 per cent fewer patients. The Y axis showed a similar change. From this, it would have to be concluded that it was not the Begg group, but the edgewise group with cervical traction, that showed a steepening of the mandibular plane. It is hoped that follow-up cephalograms can be taken of patients from both groups to see if this change is permanent. Another difference noted between the two techniques was in the area of patient comfort. A light-wire patient experiences a few days of discomfort when the initial arch wires are placed and then a few days of less severe discomfort when the third-stage arch wires are placed. The edgewise patient usually reported tenderness for a few days after each change in the arch wires. The effect of the two methods of treatment on the roots of the teeth and the supporting tissue was studied. There appeared to be more gingival hyperplasia
400
Kottraba
with the Begg method, but this soon returned to normal after the appliance was removed. This, however, was variable and was in direct proportion to the hygiene of the patient. This is considerably more difficult for the Begg patient, particularly in the third stage. The labial surfaces of the lateral incisors in two Begg patients were decalcified to some extent because of the debris allowed to remain back of the helix of the uprighting springs. This has since been eliminated by extending the bands gingivally. To determine whether or not any of the patients experienced root resorption, their final radiographs were observed independently by four dentists in general practice. It was unanimously stated that there was more root resorption in the edgewise patients. A similar assessment of the periodontoclasia was made in each group. One dentist reported that there was more alveolar destruction in the Begg group, two reported more in the edgewise group, and one stated that there was no discernible difference. All thought that it would be more significant to allow about a year to elapse following treatment before making such a radiographic evaluation. Summary
A clinical and cephalometric study was conducted to compare the treatment results achieved with the Begg light-wire appliance with those obtained with the edgewise mechanism supported by cervical anchorage. There were thirtyone patients were in the Begg group and twenty in the edgewise group. The following conclusions were reached : 1. The mandibular plane angle did not increase more in the light-wire group. 2. The occlusal plane angle increased an average of 5.7 degrees in the lightwire patients and 4.3 degrees in the edgewise patients. 3. The maxillary incisors were retracted an average of 0.6 mm. more in the Begg group. They were not elongated any more than those in the edgewise group* 4. The mandibular incisors were maintained well in accordance to the A-P line in both groups. 5. There were considerably more arches and adjustments in the edgewise group. 6. The treatment results achieved with the Begg method were at least as good as those obtained with the edgewise appliance. REFERENCES
1. Begg, P. R.: Stone Age man’s dentition, AMER. J. ORTHOIHNT. 40: 298-312, 1954. force in orthodontic treatment, AMEL J. ORTHODONT. 42:
2. Begg, P. R.: Differential 481-510, 1956.
3. Begg, P. R.: Light arch wire technique, AMER. J. ORTHOWNT. 47: 30-48, 1961. 4. Begg, P. R.: Begg orthodontic theory and technique, Philadelphia, 1965, W. B. Saunders Company. 5. Bran&, Sidney: JPO interviews, P. Raymond Begg, J. Pratt. Orthodont. 1: 16-18, 1967. 6. Crafton, GI. H.: Evaluation of anchorage in Class I and Clam II, Division 1 malocclusions treated with Begg light wire differential force technique, AMER. J. ORTFIODONT.64: 74-75,
1968.
Bqg
light-wire treatment
401
7. Halderson, H., Johns, E. E., and Moyer-s, R.: The selection of forces for tooth movement, AMER. J. ORTHODONT.39: 25-35, 1953. 8. James, Allen T.: Changes iu vertical relationships of teeth during and following use of the Begg light wire differential, AMER. J. ORTHODONT.54: 152, 1968. 9. Jarabak, J. R.: Technique and treatment with the light wire appliances, St. Louis, 1963, The C. V. Mosby Company. 10. Kimmons? James E.: Evaluation of changes in position of point A and maxillary central incisor during third stage of Begg light wire treatment, AMER. J. ORTHODONT.55: 90-91, 1969. 11. Perlow, Jack: A critique of the Begg technique from the standpoint of biomechanics, AMER.J. ORTHODONT.54: 407-432,1968. 12. Pridemore, Benjamin M., Jr.: Reduction of angle ANB in severe Class II, Division 1 using Begg light wire differential force technique, AMER. J. ORTHODONT.55: 90, 1969. 13. Reitan, K.: Some factors determining the evaluation of forces in orthodontics, AMER. J. ORTHODOKT.43: 32-45, 1957. 14. Schudy, F. F.: Vertical growth versus anteroposterior growth as related to function and treatment, Angle Orthodont. 34: 75-93, 1964. 15. Sims, Milton R.: The Begg philosophy and fundamental principles, AMER. J. ORTHODONT. 50: 15-24, 1964. 16. Steiner, C. C.: Power storage and delivery in orthodontic appliances, AMER. J. ORTHODONT. 39: 859-880, 1953. 17. Storey, E., and Smith, R.: Force in orthodontics and its relation to tooth movement, Aust. J. Dent. 56: 13, 1952. 18. von der Heydt, Karl: Can the challenge of modern orthodontic standards be met with the Beggtechniquel AMER. J. ORTHODONT.51: 321-341, 1965. 19. Williams, Raleigh: The cant of the occlusal and mandibular planes wivith and without pure Begg treatment, J. Praet. Orthodont. 2: 496-505, 1965. 168 Pennsylvania Ave. E.
I
Kottrabu,
D.D.S.,
M.S.
n 1954 the first of a series of articles that led to a new treatment philosophy was presented by P. Raymond Begg.l His accompanying technique stressed the use of light round wires and differential force in orthodontic treatment, and it has influenced the thinking of orthodontists throughout the world. The use of light wires is not an entirely new concept. The Johnson twin-arch appliance, as introduced in 1931, was the first to recognize the advantages of light resilient round wires, but the principal influence in the past decade has come from Dr. Begg. In the beginning, his concept of occlusion was at variance with the accepted view in orthodontics. Correct occlusion, according to Begg, is not a static condition ; in fact, the only constant in correct occlusion is continual change. Throughout life, teeth continually migrate in two directions-horizontally (mesial migration) and vertically (continual eruption). This concept of normal occlusion was developed after a thorough study of skulls of the Australian aborigine. The two major factors to be considered in producing anatomically correct occlusion in the Australian aborigine are tooth migration and attritional tooth wear. Begg contends that attritional occlusion involves a wearing away of tooth cusps, a reduction in arch length, and establishment of an end-to-end incisor bite ; it explains Angle’s Class III occlusal relationship, it results in the only anatomically correct occlusion, and it has the constant quality of continuous change throughout life. Conversely, Begg contends that the SOcalled textbook normal occlusion, with the teeth almost unworn throughout life (both occlusally and interproximally) and with high interlocking cusps and a moderate to deep overbite, is anatomically abnormal. One skull shown by Begg illustrates tooth attrition in which the lower first molar is worn down to the cementoenamel junction. He estimates that, on the average, there is an approximate mandibular arch reduction of 14.7 mm. This gives him the basis for the etiology of crowding and third molar 386
Volume
Number
Begg light-wire treatment
59 4
impactions ; hence, the rationale in certain cases. History
for
extracting
four
for
his technique
and even eight
387 teeth
of the appliance
Begg2 makes certain claims In his 1956 article he wrote:
that
seem to be valid.
All required tooth movements-bodily, torquing, and tipping-can be performed with this technique . . . . the use of thin round steel arch wire raises the standard of results, as it eliminates the excessively high forces that are exerted by rectangular arch wire. Active treatment time is greatly reduced. . . , Nevertheless, it is a fortunate coincidence that the orthodontic force values that are used cause least discomfort to patients, least loosening of teeth, and least damage to tooth-investing tissues, while at the same time they are also the forces that move teeth the most rapidly and are the most easily controlled forces.
Begg spent more than 20 years in the development of his technique, beginning a few years after he attended the Angle course in Pasadena :from March, 1924, to November, 1925. Following his completion of the course, he returned to Adelaide and practiced orthodontics with the edgewise mechanism. Through trial and error, he evolved a system of .tipping and uprighting rather than bodily movement for the positioning of .teeth. The principle of individualized tooth control-a cardinal feature of the edgewise appliance-is neither sacrificed nor contradicted with the use of light resilient’wires in the modified ribbon brackets that Begg developed for his treatment procedure. Other chief improvements are the extremely efficient sectional torquing arches, uprighting springs, lingual buttons, and the realization that, with this method, it takes just as long to finish treatment according to acceptable standards as with any other technique. Differential
force
The principle8 of differential force can be applied by an orthodontist with the light-wire mechanism because he has the option of either tipping the teeth or moving them bodily. Storey and SmithI’ explored the possibility of finding an optimum force in their study of tooth movement. They used the edgewise appliance for experiments with spring forces of varying values to move canines distally. First permanent molars, together with second premolars, were used as anchorage for the springs to move the canines into the premolar extraction spaces. Their findings show that similar behavior of the teeth occurred in all cases studied. They found that there is an optimum range of force values to produce a maximum rate of movement of the canine. This force range for moving a canine distally is between 150 and 200 Gm. Mesial movement of the molar-premolar anchor unit occurred in the high range of force values, 300 to 500 Gm. When the force was below 150 Gm. for the canine and below 300 Gm. for the anchor teeth, neither moved appreciably. Begg2 found that the light force value advocated by Storey and Smith (or slightly less) was optimum for moving a canine ; he found also that this
388
Kottraba
force need not bc incrcascd proportiona.lly, and perhaps not at ail, for t.he simultaneous backward movement of the six anterior teeth in order to close the first premolar extraction spaces. The YOWC~S found by Storey and Smith to be the most favorable for tooth movement from the standpoint of rapidity and tissue tolerance a.re much lower t,han those exerted by the edgewise arch wire. Halderson and associates7 state t,hat in many instances the force exerted by an edgewise arch wire is of the .very high value of ovel 2 pounds, or approximately 900 Gm., which causes a pathogenic tissue response. Steiner,16 in considering the question of arch wire force, states that any tooth movement might be accomplished with just one a.djustment if the arch wire were to be reduced sufficiently in size. He also says that this has been proved by all who have used the 0.018 inch or even the 0.022 inch round steel arch wires in competition with heavier forces. He states that the edgewise appliance principles may someday be applied by using an arch wire of an extremely elastic metal with a diameter that may be only a small fraction of the cross section of the present one. Steiner also points out that, to gain much tooth movement, whether it be rot.ation torquing or mesial or distal tipping, a great deal of force must be applied to distort the short rigid section of the edgewise arch wire enough to accomplish power delivery. Clinicians7 using t,he edgewise mechanism have learned to start their treatment with a series of light round wires. This is sound treatment for two reasons: (1) it takes advantage of tipping movements and (2) it utilizes forces that are much lighter than is standard with an edgewise wire. Begg” felt that this statement implied a need for an appliance that will deliver a sufficiently light force and, at the same time, accomplish universal tooth movement throughout treatment. Reitan13 advocates the use of light continuous forces, but he is strongly opposed to a tipping movement since, because of the mechanical principles involved, the forces create compressed cell-free areas in the periodontal membrane more frequently than those created in a bodily movement. Jarabakg states that some clinicians advocate the tipping of crowns into their desired positions in the arch and the later uprighting of their roots. These uprighting mechanics are accomplished with long-moment arm levers fashioned as auxiliary spring loops. darabak is strongly opposed to this type of movement because of the damage to alveolar bone and resorption of roots. He demonstrates this by means of serial radiographs. The three
stages
in the
Begg
technique
In a recent interview,5 Begg stated that there are no basic mod&ations of the technique since the publication of his article entitled “Light Wire Technique. ’‘3 The light round arch wire differential force treatment technique is divided into three separate and distinct stages that must not be allowed to overlap. The following conditions are overeorrected during the first stage of treatment: crowding, anterior spaces, rotations, deep anterior
Volume Number
Begg light-wire
59 4
treatment
389
overbites, anterior open-bites, anteroposterior discrepancies, arch contour and coordination, and all cross-bites. In the second stage of treatment all overcorrections are maintained and any remaining extraction spaces are closed. In the third and final stage the axial relations of all upper and lower teeth are corrected simultaneously.4 Cephalometric
analysis
The literature contains many applications of cephalometric analysis to evaluate the results achieved by the Begg technique. If the differential force theory is to be substantiated, then anchorage control must be demonstrated. Williamslg found that it is significant, with the Begg treatment, that the in&al edge of the lower incisors reaches a final position quite close to the A-P line-a critical position if upper and lower lip balance is to be achieved. He found that the major expenditure of anchorage occurs during the third stage and that this must be anticipated in treatment calculations. Grafton found that, in the treatment of Class I malocclusion, 47.5 per cent of the maxillary extraction space and 51 per cent of the mandibular extraction space beyond that required for alignment of the teeth is closed by forward movement of the anchor teeth. In the treatment of Class II, Division 1 malocclusion, 23 per cent of the maxillary extraction space and 97.2 per cent of the mandibular extraction space is closed by forward movement of the anchor teeth. Correction of the molar relationship is accomplished mainly by the forward movement of the mandibular first molars. PerlowlL believes that Class II elastics are contraindicated in patients described by Schudy14 to be hyperdivergent, and he therefore believes that the Begg technique cannot be used. Schudy designates a steep mandibular plane as being hyperdivergent and a flat plane as being hypodivergent. On the other hand, Perlow considers Begg treatment ideal for the hypodivergent types. He also states that the treatment of mature patients by means of unlimited tipping and countertipping is open to serious questions. Williams1g states that, in general, without treatment, the flatter the mandibular plane, the greater the tendency for it to become even flatter during the growth period. The steeper the mandibular plane, the less intense is its tendency to flatten during the growth period. Pure Begg treatment instituted during the growth period may inhibit the flattening process and temporarily countermand it. However, if there is a growth period following treatment, the flattening process will reassert itself and temporary inhibitory effects of treatment may be more than totally compensated for, depending on the magnitude and duration of the posttreatment growth phase. James8 concurs and shows that the Frankfort-mandibular plane angle increases slightly during treatment but decreases during a 2-year posttreatment period. Nor is the vertical height of the upper incisor changed by any significant amount. Deep overbite is corrected by elevation of the lower molar and depression of the lower incisors. After 2 years, there is approximately a 51 per cent return of the overbite.
390 Kottraba
A
C
Fig. 1. Attachments used in Begg light-wire treatment. A, Doubled-back arch wire ends are inserted in oval tube on second molar. They are used when first molars have been extracted. B, Lingual button with elastic ligature for rotation. C, Lingual buttons for maintaining closure of extraction spaces. D, An “udder’” arch to support mandibular anchorage. (No reference in text.)
Williamsls also states that the pure Begg technique is effective in the vertical control of the upper incisors. Kimmonsl” reports no significant change in the measurement from the palatal plane to the tip of the upper incisors during Begg treatment. He also found an improvement in the maxillary and mandibular apical base relationship a,s a result of the posterior movement of point A. Pridemore l2 found that the mean reduction of the ANB angle in twenty-one patients was 3.07 degrees a.nd that this was accomplished primarily by the posterior movement of point A. Begg
treatment
procedures
The following is a description of the Begg technique as currently applied. In a four-tooth extraction case, all of the teeth from the first molars forward are banded. All but the molar bands receive a ribbon type of bracket, and a buccal tube is placed on the molars parallel to the occlusal plane. If the first molars are extracted, oval tubes are placed on the second molars, which receive a doubled-back arch wire (Pig. 1). Lingual buttons, which are used for rotation and for maintaining the closure of the extraction spaces during the
Volume SY Number 4
Begg light-wire treatment
391
Fig. 2. Various 0.016 inch looped initial arch wires. Note the molar anchor bands, bypassed premolar brackets, and Class II elastics that are usedin the first stage of treatment.
third stage, are placed on the lingual aspect of the molars, premolars, and canines. The initial arch wire for Stage I is 0.016 inch in diameter. It is either fabricated directly at the chair or indirectly from a previously measured chart, starting at the left buccal tube and placing intermaxillary hooks just mesial to the canine brackets. Vertical loops are placed at each broken contact for irregular teeth (Fig. 2). When the wire is passive, the intermaxillary hooks lie distal to the canine brackets, so that when the wire is pinned a compressive force will reciprocally drive the canines distally. If there are anterior spaces, the intermaxillary hooks are a few millimeters mesial to the canine brackets to allow closure of the space by a canine-to-canine elastic. Strong anchor bends are placed just mesial to the buccal tubes, approximately at the interproximal space. The premolars are not pinned but are only tied loosely to the arch wire. A Class II intermaxillary elastic with a force range of 2 to 21/ ounces is placed immediately. Cross elastics are used in the event of cross-bites, and elastic ligatures are used to tie rotations. As soon as the irregularities have been overcorrected, the looped arch wire is replaced with an arch wire (with bayonet bends) that will maintain the overcorrected positions of the teeth. The canine intermaxillary hooks are ligated to the distal brackets to prevent
Fig. 3. Start of the second treatment stage. lntramaxillary tion spaces. Stage 1 objectives have been accomplished, relationship.
elastics are used to close extracwith the incisors in an end-to-end
anterior spacing. Treatment continues in this fashion until all of the Stage I objectives have been reached. This ordinarily takes from 3 to 6 months. Usually, the only arch adjustment required in the first stage is in positioning the anchor bend further mesially to prevent its binding in the buccal tube. In the second stage of treatment, the same arch wires are used and intramaxillary elastics are placed in the four posterior quadrants until the extraction spaces are closed (Fig. 3). Class II or Class III elastics are applied as needed. The wire is still not engaged into the premolar bracket in Stage II. In the third stage, the lingual buttons on the molars and canines are ligated with 0.012 inch stainless steel wire (Fig. 4). The maxillary arch is constricted to counteract the resultant force of the auxiliary torquing arch. The main arch is now seated into the premolar brackets and tied into place. Ties are used in place of pins wherever uprighting springs are indicated. The maxillary incisors receive the auxiliary torquing mechanism, and 0.014 inch helical uprighting springs are placed as needed on the premolars, canines, and lateral incisors. Class II intermaxillary force is needed in this stage to maintain an edge-toedge position of the incisor. The length of treatment in Stage III is approximately the same as in the first two stages combined. When the axial relations of
Volume Number
59 4
Begg light-wire treatment
393
Fig. 4. Stage 3 mechanics near the end of application, The torquing and uprighting auxiliaries are shown in place to correct the inclinations. The ends of the arch wires are bent over the tubes to help in maintaining extraction space closure. Class II or Class III elastics are worn as needed to maintain an end-to-end relationship of the anterior teeth.
the teeth appear clinically close to being correct, a Panorex film is taken to determine the need for any final positioning. A fourth stage is advised during the final months of treatment (Fig. 5). Finishing arches, 0.018 inch in diameter, are placed to complete and refine positioning and to aid in closing space when the anterior and premolar bands are removed. Retention is routinely carried out with a maxillary Hawley type of retainer and a fixed mandibular canine-to-caninelingual arch. Material
and
methods
A total of thirty-one patients, including six nonextraction patients, treated by the Begg technique were assessedradiographically, cephalometrically, and clinically. Fifty-six per cent of these were classified as having Class I irregularities and 44 per cent as having Class II irregularities. A similar analysis was applied to a sample of twenty casestreated with the edgewise appliance. O f these, 25 per cent had Class I and ‘75 per cent had Class II malocclusions. All of these patients wore cervical extraoral appliances for all or part of their treatment (Table I). For the cephalometric measurements,the S-N line was used for a reference
Fig. 5. Finishing arches, 0.018 inch in diameter, are used in the “fourth” stage to accomplish any necessary final positioning. These same arches are then used to close band spaces during the band-removal procedure.
plane. The following measurements were used: SNA, SNB, ANB, i-SN, l-NA (mm.), l-NA (degrees), i-NB (mm.), i-NB (degrees), i-i, occlusal-SN, G6GNSN, Y axis (to SN) , i-AP (mm.), and I-ANS-PNS (by a perpendicular from ANS-PNS to the 1 incisal). Measurements were taken from the original and final cephalograms, and all differences were recorded. To determine which group suffered the most root resorption and periodontoclasia, the final Panorex film of each patient was attached to a glass wall in one of two unmarked groups, so that all could be viewed simultaneously. Four dentists in general practice were asked to assessthese films. Also compared in the two types of treatment were treatment time, the number of arch wires used, and the number of adjustments made. Since the six nonextraction patients in the Begg group were treated much faster and usually did not require a typical three-stage treatment, their cephalometric measurements were not used for the final averages. Discussion
In several studies comparing treatment techniques, the patient samples came from separate practices. There is a danger here that, instead of the effectiveness of the technique being determined, the ability of the operator may be
Volume Number
59 4
Begg light-wire
treatment
395
A
B
C
D
E
F
Fig. 6. Patient J. F. A, B, and C, Pretreatment photographs of a boy 14 years 5 months of age with a Class II, Division 2 malocclusion. Note the extreme overbite and lack of canine space in the maxilla. The mandibular anterior teeth are 8 mm. behind the A-P line. D, E, and F, Photographs taken 2 years after 23 months of nonextraction treatment with the light-wire appliance. The mandibular anterior teeth are now on the A-P line. The FMA was originally 27 degrees, and it now measures 25 degrees. A maxillary Hawley type of retainer is still worn at night. The Class I relationship of the buccal segments and the correction of the overbite appear to be stable.
evaluated. This study should be more valid becauseall the patients were treated by one operator with similar training and experience in each of the techniques used. Much has appeared in the literature concerning the shorter treatment time that is possible with the Begg method. It was found that edgewise treatment
396
Kottruba
B
D
F
Fig. 7. Patient age
with
a
relationship. anterior after
teeth active
continued Note the
T. A. A, B, and Class
II,
There
is
a
are
2 mm.
light-wire for
reduction paralleling
22
of the
2
ahead
teeth
The
anterior of the
treatment. the
adjacent
Hawley satisfactory to the
premolars type
of
torque
extraction
15 years
segments
and
overjet,
D, E, and
line.
first
of a boy
posterior
overbite
A-P
Four
A maxillary
overbite,
photographs
malocclusion.
moderate
months.
of the
C, Pretreatment
Division
and
F, Photographs were
retainer of the
is now
in
the
II
mandibular
and
worn
of
a Class
taken
removed,
maxillary
4 months
ar’e
only
anterior
4 months treatment at teeth,
night. and
sites.
took an average of 1 month longer. When treatment in either group exceeded 2 years by any great amount, cooperation of the patient was always lacking. On the average, more arch wires were used to treat an edgewise case (14.4) than to complete a Begg case (5.4). Also, more adjustments (9) were required for the edgewisegroup than for the Begg group (4.3). It was shown that Point A was moved nosteriorlv. as exnressed bv the SNA L
*-
+
.
Volume 59 Nuwkber 4
Begg light-wire
treatment
397
Fig. 8. Patient S. M. A, B, and C, Pretreatment photographs of a girl 11 years 3 months OP age with a high mandibular plane angle of 29 degrees and a large ANB angle of 9 degrees. The patient exhibited marginal gingivitis of the maxillary anterior teeth, mostly caused by difficulty in closing the lips and consequent mouth breathing. D, E, and F, Photographs taken 21/z years after treatment with the light-wire appliance, 6 months out of retention. Treatment consisted of the extraction of four first premolars and use of the appliance for 18 months. The ANB angle was reduced to 5 degrees and the FMA closed from 29 degrees to 26 degrees. Note the marked improvement in the gingival tissue.
angle, an average of 0.5O more by edgewise treatment and that this occurred in a few more patients (9 per cent). This difference does not seem great enough to be significant. Point B reacted similarly to treatment with both techniques. The angle ANB was reduced in 30 per cent more patients treated with the ed.gewiseappliance, but again the average difference was only 0.5 degree. Torquing of the maxillary anterior teeth was more effective with the Begg
Patients
in sample
31 (25 extraction;
20 (19 ext,raction j I non. extraction
1
ilxtrxctiotr
Class I
25%
5670
Class II
75%
.14%
25. I
24.::
7.4
Average time
6 non
)
treatment (months)
Maxillary
arches
7.0
48 .+..q 2.5
adjustments
5.8
‘I._ 7 .I
3.2
2.1
arches
Mandibular Maxillary Mandibular
adjustments
Cephalometric
measurememts
Increase
average finish
lkcrease
,
!
Same
Edgewise SNA
(degrees)
1.25 ( 10%)
SNB
(degrees)
ANB
(degrees)
1 ( 10%) 1.8 ( 30%) 96.2
1 SN (degrees), ~NA
(mm.)
1NA TNB
(degrees) (mm.)
iNB
(degrees)
l/l
(degrees)
SN-occlusal
(average
SN-mandibular SN-Y
135.8)
(degrees) (degrees)
axis (degrees)
i palatal
(mm.)
15% 25%
4.3 ( 95%)
1 ‘2
( 5%) ( 10%)
2
( 30%)
2.T5 ( 60%)
6 15.1
( 50%) ( 90%)
6.9 6
( 50%) ( 10%)
4.3
( 85%)
3.7
( 15%,l
1.9
( 70%)
1.X ( 70%) 1.8 (100%)
(mm.)
TAP average finish
3.5 ( 75700) 1.9 ( 65%) 7.7-a( 70%)
Il.:{
( 90%)
.;3 ( 10%) 1
!
15%)
+I
-.. 10% -. 20% 15% --
Begg light-wire SNA
(degrees)
1.3 ( 20%)
1.9 ( 68%)
SNB
(degrees)
1
(24%)
1.6
ANB
(degrees)
9 98
(48%)
1.2 ( 40%)
12% wso w40
5.1
(100%)
_--
12.3
( 80%)
4%
2.3
( 72%)
3.9
( 32%)
20% 8%
1SN (degrees), ~NA ANA
average finish
(mm.) (degrees)
2.75 ( 16%)
TPTB (mm.) iNB l/l
1.5
(degrees) (degrees)
(
8%)
6.2 ( 60%) (average
131)
SN-occlusal (degrees) SN-mandibular (degrees) SN-Y axis (degrees) 1 palatal (mm.)
TAP average finish (mm.)
15.6 5.7 I 1.9
( 64%)
( 76%) ( 84To)
7.2
( 24%)
2.6
( 12%)
52%) 64%)
1.9 1.5
( 24%) ( 20%)
1
(
i (
1.B ( 72%) +1.3
12%)
24~~
16% 33%
Volume Number
59 4
Begg light-wire treatment
399
technique, as shown by the l-SN angle average of 98 degrees as compared to 96.2 degrees in edgewise tr&tment. However, since the ideal is 103 degrees, both methods fell short in this study. The ability of both methods to control the elongation of the upper incisors was evaluated by the l-ANS-PNS measurement. It is recognized that the validity of this measurement can be questioned because increased growth and upper incisor inclination can change the reading severely. However, the two groups were selected to have as many of the same characteristics as possible. One hundred per cent of the edgewise patients showed an average increase of 1.8 mm., whereas 12 per cent of the Begg patients showed a 1 mm. decrease and the average increase was 0.2 mm. less. One would have to conclude that the Begg method proved more effective in the vertical control of the upper central incisors. It should be remembered that a high-pull headgear was not used. Retraction of the upper incisors was slightly more effective (0.6 mm.) with the Begg method. This is most interesting when one considers that no extraoral traction was used. The reaction of the lower incisor was similar in both samples, except that the apex was moved further lingually by the Begg method, which, in turn, resulted in a better 1-i angle (average, 131 degrees) and a greater lower incisor CNB angle. The in&al edges of the lower incisors were positioned close to the AP line in both groups (+ 1 mm. in the edgewise group and + 1.3 mm. in the Begg group). The behavior of the occlusal plane was the same for both groups, in that it became steeper. The Begg group averaged an increase of 1 degree more than the edgewise group, however. This was probably due to the elevation of the lower molar by the Class II elastic force. Although there has not been enough time for a postoperative study, other investigators have shown that the increased occlusal-plane cant will flatten later.lg Full control of the vertical dimension during Begg treatment has been questioned because of the Class II elastic force that is used throughout the three treatment stages. The two measurements used to evaluate the rotation of the mandible and the consequent opening of the bite are the mandibular plane to SN angle and the Y axis angle (measured to SN). The findings reveal that, on the average, the mandibular plane angle increased 0.9 degree less for the Begg patients, for 18 per cent fewer patients. The Y axis showed a similar change. From this, it would have to be concluded that it was not the Begg group, but the edgewise group with cervical traction, that showed a steepening of the mandibular plane. It is hoped that follow-up cephalograms can be taken of patients from both groups to see if this change is permanent. Another difference noted between the two techniques was in the area of patient comfort. A light-wire patient experiences a few days of discomfort when the initial arch wires are placed and then a few days of less severe discomfort when the third-stage arch wires are placed. The edgewise patient usually reported tenderness for a few days after each change in the arch wires. The effect of the two methods of treatment on the roots of the teeth and the supporting tissue was studied. There appeared to be more gingival hyperplasia
400
Kottraba
with the Begg method, but this soon returned to normal after the appliance was removed. This, however, was variable and was in direct proportion to the hygiene of the patient. This is considerably more difficult for the Begg patient, particularly in the third stage. The labial surfaces of the lateral incisors in two Begg patients were decalcified to some extent because of the debris allowed to remain back of the helix of the uprighting springs. This has since been eliminated by extending the bands gingivally. To determine whether or not any of the patients experienced root resorption, their final radiographs were observed independently by four dentists in general practice. It was unanimously stated that there was more root resorption in the edgewise patients. A similar assessment of the periodontoclasia was made in each group. One dentist reported that there was more alveolar destruction in the Begg group, two reported more in the edgewise group, and one stated that there was no discernible difference. All thought that it would be more significant to allow about a year to elapse following treatment before making such a radiographic evaluation. Summary
A clinical and cephalometric study was conducted to compare the treatment results achieved with the Begg light-wire appliance with those obtained with the edgewise mechanism supported by cervical anchorage. There were thirtyone patients were in the Begg group and twenty in the edgewise group. The following conclusions were reached : 1. The mandibular plane angle did not increase more in the light-wire group. 2. The occlusal plane angle increased an average of 5.7 degrees in the lightwire patients and 4.3 degrees in the edgewise patients. 3. The maxillary incisors were retracted an average of 0.6 mm. more in the Begg group. They were not elongated any more than those in the edgewise group* 4. The mandibular incisors were maintained well in accordance to the A-P line in both groups. 5. There were considerably more arches and adjustments in the edgewise group. 6. The treatment results achieved with the Begg method were at least as good as those obtained with the edgewise appliance. REFERENCES
1. Begg, P. R.: Stone Age man’s dentition, AMER. J. ORTHOIHNT. 40: 298-312, 1954. force in orthodontic treatment, AMEL J. ORTHODONT. 42:
2. Begg, P. R.: Differential 481-510, 1956.
3. Begg, P. R.: Light arch wire technique, AMER. J. ORTHOWNT. 47: 30-48, 1961. 4. Begg, P. R.: Begg orthodontic theory and technique, Philadelphia, 1965, W. B. Saunders Company. 5. Bran&, Sidney: JPO interviews, P. Raymond Begg, J. Pratt. Orthodont. 1: 16-18, 1967. 6. Crafton, GI. H.: Evaluation of anchorage in Class I and Clam II, Division 1 malocclusions treated with Begg light wire differential force technique, AMER. J. ORTFIODONT.64: 74-75,
1968.
Bqg
light-wire treatment
401
7. Halderson, H., Johns, E. E., and Moyer-s, R.: The selection of forces for tooth movement, AMER. J. ORTHODONT.39: 25-35, 1953. 8. James, Allen T.: Changes iu vertical relationships of teeth during and following use of the Begg light wire differential, AMER. J. ORTHODONT.54: 152, 1968. 9. Jarabak, J. R.: Technique and treatment with the light wire appliances, St. Louis, 1963, The C. V. Mosby Company. 10. Kimmons? James E.: Evaluation of changes in position of point A and maxillary central incisor during third stage of Begg light wire treatment, AMER. J. ORTHODONT.55: 90-91, 1969. 11. Perlow, Jack: A critique of the Begg technique from the standpoint of biomechanics, AMER.J. ORTHODONT.54: 407-432,1968. 12. Pridemore, Benjamin M., Jr.: Reduction of angle ANB in severe Class II, Division 1 using Begg light wire differential force technique, AMER. J. ORTHODONT.55: 90, 1969. 13. Reitan, K.: Some factors determining the evaluation of forces in orthodontics, AMER. J. ORTHODOKT.43: 32-45, 1957. 14. Schudy, F. F.: Vertical growth versus anteroposterior growth as related to function and treatment, Angle Orthodont. 34: 75-93, 1964. 15. Sims, Milton R.: The Begg philosophy and fundamental principles, AMER. J. ORTHODONT. 50: 15-24, 1964. 16. Steiner, C. C.: Power storage and delivery in orthodontic appliances, AMER. J. ORTHODONT. 39: 859-880, 1953. 17. Storey, E., and Smith, R.: Force in orthodontics and its relation to tooth movement, Aust. J. Dent. 56: 13, 1952. 18. von der Heydt, Karl: Can the challenge of modern orthodontic standards be met with the Beggtechniquel AMER. J. ORTHODONT.51: 321-341, 1965. 19. Williams, Raleigh: The cant of the occlusal and mandibular planes wivith and without pure Begg treatment, J. Praet. Orthodont. 2: 496-505, 1965. 168 Pennsylvania Ave. E.