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Variations in edgewise biomechanics
American Journal of ORTHODONTICS Volume
64, Number
4, October,
1973
ORIGINdAL ARTICLES
Variations in edgewise biomechanics C. W. Palo
Alto,
Carey,
D.D.S.
Calif.
T
his concept is the culmination of ideas, philosophy, and treatment strategy put to the test first in the laboratory and then applied clinically. Many of th.e mechanical innovations had to be rejected, supplemented, or refined, and the treatment philosophy had to be revised as we became more concerned with new concepts and influenced by the work of contemporary researchers. The search for better treatment mechanics and strategy was inspired by the conviction that some of the current methods were not satisfactory, often cumbersome, inefficient in force control, and guilty of undesirable tooth movement. They involved unnecessary and often anchorage-weakening steps in early leveling for bracket engagement and mass movement of teeth locked together prematurely in ideal arch form, requiring the use of prolonged and extensive extraoral force. This latter procedure may result in a pseudocentric relationship. When dental arches are formed to fit each other before .they are positioned together anteroposteriorly, it is difficult to know when the correct centric relation has been established. The functional interdigitation of teeth should be subservient to the temporomandibular articulation. Iatrogenic temporomandibular joint problems may arise subsequent to treatment because of a malrelation between centric occlusion and centric relation, and frequently in Class II correction what is commonly referred to as a “creeping” or ‘Lend-on” cusp relation occurs. This is the beginning of a relapse precipitated by the tendency of the hinge axis of the masticatory mechanism to establish its own authentic occlusion. Clinical experience illustrates that in nonextraction cases the maxillary molars should be moved distally to occlusion with the mandibular molars first. Then the unbanded premolars are allowed to find their natural occlusion with the assistance of a light helical spring force. This creates an authentic occlusion 337
Am. b. Qrthod. October 1973
Fig.
1. Nonextraction.
Class
II,
Division
1.
and not the mesiaP creeping of the maxillary posterior teeth that formerly occurred when all of the teeth were banded prior to the Class II eorreetion. The principal policy of action is to move teeth with light forces in small units or to not move them at all but provide the lessened resistance in the path of desired movement so that they will move by themselves in a physiologic manner. It seems reasonable to assume that if teeth for which space is provided move into more desirable locations, they are more likely to stay there without restraint. Posterior corrections are made first, so that room may be provided for the anterior teeth. Consistent with this philosophy, with few exceptions, teeth should not be moved in any direction except toward the desired point of correction. Incisors should not be banded and aligned when they have no place to go. Also of questionable value is the use of Class III force to set up anchorage in Class II cases. When teeth are disturbed, and osteoclastie and osteoblastic action is in full force, their performance as an anchorage base for moving other teeth is weakened. Treatment should be started slowly, with simple mechanics and few bands, so as not to block natural progress and to permit gradual self-correction before adding to the appliances. The description of the mechanical approach to be advocated will be managed in three phases. The first is the distal movement of maxillary teeth in nonextraction cases with Class II cuspal relation, no mandibular discrepancy, and no extreme skeletal disharmony (Fig. 1). The mechanism used in the ma.xillary arch is the sliding ribbon section (Fig. 2, A). In the mandibular arch we use the loop lingual arch in conjunction with the rectangular loop arch (Fig. 2, C) , The principal advantage of the sliding section is to move the molars distally with the controlled light force of an 0.011 by 0.022 inch wire, extraoral traction, and some Class II elastics to keep the force 100 per cent constant. This arch does not expand in the molar region but acts as a guide wire to keep the posterior teeth in the soft medullary bone area. The molar correction is followed by the premolars, then the canines in turn, and finally the incisors. The reduction of the molars to a Class 1 relation should be
Volume Ntimber
64 4
Variations
Fig. 2. A and
B, New improved
tanguiar
loop
labial
retractor. Correction
F, Rectangular in alignment
arch
with
loop before
,iv% edgewise
biomechanics
339
sliding ribbon section suggested by Dr. Picard. C, Recloop lingual arch. 8), Plate premolar retractor. E, Cuspid G, Patient with crowded lower incisors. H, with Router. band
placement.
accomplished in a few months, the premolar retraction in 2 months, and the canine retraction in 1 month. Fig. 2, B shows a case under treatment as a typica exampIe. The upper appIiante is extended by placing an elastic module from the distal cleat to the mesial hook on each side. This is supplemented with a headgear 14 hours per day and light Class II elastics. When the molar has moved just bleyond Class I relation, the plate retractor with its helical finger springs (Fig. 2, D) is placed to move the premolars back. No Class II elastics are worn at this time. The canine retractor (Fig. 2, E) is then slipped beneath the anterior arch and the cleat is .tied back to the molar. The use of Class II elastics is resumed. The retractor
340
Carey
is then removed and use of a tie-back with elastic modules is continued for Fetraction of the incisors. The lower incisors are aligned and depressed to level off the arch with the loop lingual arch applying pressure on the cingulum of these incisors. If the orbicularis oris is strong, an 0.045 inch bumper arch is used labial to the incisors to exert distal pressure on the mandibular molars. The lower second premolars are banded after the molars have been uprighted, and a rectangular loop labial arch (Fig. 2, C) is placed and tied through to the lingual arch distal to the central incisors. This arch is set gingiva,lly in the anterior region and tied back periodically each time the loops on the lingual arch are opened. We have treated hundreds of cases with this same technique over the past 20 years. The sliding section arches are easily constructed by the technician. The parts are the two side hook se&ions of 0.021by 0.025 inch and the anterior section, 0.011 by 0.022 inch, which is held by an 0.036 inch spacer welded to the side section distal to the hook. The terminal two-way cleat is held in place by an 0.036 inch spacer. The arch gives an excellent opportunity to treat unilateral Class II conditions, since the opposite arch segment is not working against the side put in motion. This same mechanism is used in the maxillary arch in an extraction case to reduce the Class II malocclusion to Class I and open the bite. The second phase of this treatment concept is concerned with the management of the mandibular arch following extraction of the first premolars. It is a means, with minimal banding, of uprighting and then distally tipping the pasterior teeth, depressing the incisors, opening the b’ite, and permitting selfalignment of incisors and distal drift of canines. It is the most efficient method of handling extraction cases that we have used. The treatment is accomplished by the use of the loop lingual arch in conjunction with the rectangular loop arch (Fig. 2, C) which is used in two gauges, first the 0.017 by 0.025 inch and then 0.021 by 0.025 inch (Fig. 4, B) . The chief justification for the use of this combination of a labial and lingual arch is that, in performance, the posterior teeth seldome moved forward, while the unbanded incisors align and move back several degrees to the NB plane. The extraction space is reduced with the distal drift of the canines, and anchorage is thus conserved by minimizing the amount of canine retraction necessary for space closure. The lingual arch extension is synchronized with the labial arch retraction. Later, the floater (Fig. 2, P) is added to the rectangular arch to retract the root of he lower canine if necessary. A case under treatment (Fig. 2, G and H) demonstrates this operation. The third phase deals with the application and uses of the laminated arch. Laminated arches are split vertically 0.011 by 0.022 inch to form a DRII, 0.022 by 0.022 inch (double ribbon), or horizontally 0.0105 by 0.025 inch to form a, DEII, 0.021 by 0.025 inch (double edgewise). They are held together by spacer tubes, 0.030 inch, and adjustable stop hooks. The DEII, double-edgewise arches, are used extensively in our treatment program. They are used as sectional arches with a clover loop and stop for space closure (Fig. 3, A), in full arches, clover and V loop (Fig. 3, B) , in the final space-closing operation in extraction cases, and as a finishing arch with double helical loops (Fig. 3, C) . In explanation of the fabrication of these arches, let us take the finishing
Volunw Number
64 4
Fig. 3. A, Clover laminated finishing
Variations
loop laminated arch. D, Initial
section. 6, Clover step in laminated
in edgewise biomechanics
vertical loop arch fabrication.
arch.
C,
Double
341
loop
double-loop laminated arch as an example. It is made from the arch measurement taken with a wax strip which is softened and applied to the teeth from molar to molar and pressed gently against the brackets and attachments to make an imprint in the wax. The location of loops is marked by indenting the wax with a pencil point. This is transferred to a pad with a straight line on which the loops and arch length are indicated. The technician fabricates the arch in time for the next appointment. Ribbon arch pliers No. 142 with 0.022 by 0.028 inch slot and loop-forming pliers are used to form the arch. It is important that one end of the arch be open and the other end closed (Fig. 3, D). Three spacer tubes, 0.030 inch by 1 mm., are placed on the arch with the open end turned in the opposite direction so that the spacers will not slide off. A full 1Pinch length doubled over from the center is used to form the arch. In forming the loops, one should start at the closed end, being sure to work toward the open end with a spacer close to the working area. The open end permits freedom for shifting the lamina in forming the loops. Arches are always formed in a straight line before contouring, The contouring is done after the loop formation with the turret, as with a solid arch, and the offset and canine contour bends are made with the ribbon arch pliers. The open end is welded after the loops are formed. Use of the double-loop laminated arch (Fig. 3, C) is standard for our finishing procedures. In first-premolar-extraction cases the loops are located on the mesial and distal of the canine bracket. In the lower arch, the distal loop is made by starting with a gingival bend and the mesial loop is started with an occlusal bend. In the upper arch the procedure is reversed. The activated loops exert a continuous action on the canine roots to move their apices distally in extraction cases. Since the introduction of the module elastics, it is possible to omit the tieback hook and place a module from the molar hook to the distal loop. In the case of a second premolar or molar extraction, the first loop is in the extraction space and the second loop is mesial to the canine. In the lower arch, the mesial loop may also be formed by starting with a gingival bend to provide more efficient lingual root torque for the four anterior teeth. In the upper arch the reverse applies. When torque is incorporated in the arch wire, the action and power are stored in the mesial loops, and the arch wire is placed in the brackets easily and without excessive force or discomfort, It will generally require 6 weeks for
342
Am. J. Orrhod. October 1973
Carey
the incisors to assume the projected axial position directed by the laminated arch wire. The advantages of the laminated loop arch are ease of seating in the brackets which they fill, a resiliency which is eight times greater than that of the solid arch,l the continuous action to paralel roots of the canine and premolar, horizontal strength for arch form, and continuous action for effecting torque. Technical
application
of
the
four
principal
arrhes
in
fke
discrepancy
case
Preferentially, the upper second and lower first premolars are extracted in arch-length-deficiency cases. In such cases the discrepancy is usually confined to or greater in the mandibular than in the ma.xillary arch. If the discrepancy is not major, the removal of the first premolars may produce too much reduction and an unpleasant facial contour, It is almost impossible to “dish in” a face if the upper second premolars are removed. The upper first premolar, with its broad buccal plate of enamel, is a better anatomic specimen than the second premolar, and the esthetic appearance of the dental arch in the finished case is enhanced by its presence.% The remaining teeth have better articulation because the two smaller opposing teeth a.re removed instead of the smaller teeth below and the larger ones above. Contraindications to this selection would be in extreme discrepancies and Class II deep-bite cases. In these conditions, the first premolars are removed. Anchorage conservation and simplic.ity of appliance design and treatment procedures are the keynote to efficiency in the program plan for an esthetic and stable correction. If we have a discrepancy ca,se involving extraction of premolars, we do not approve of banding all available teeth and placing leveling arches. This procedure moves incisors labially, starts osteoclastie action in the entire peridontium, and weakens our precious anchorage, and we must now resort to external force to hold the posterior teeth back. Extraoral force in extraction cases should be used to reduce the Class II cuspal relation of the teeth and only very rareiy to reinforce anchorage. As an example, let us consider a Class I, deep-bite, 7.0 mm. discrepancy case in which the upper second and lower first premolars have been eliminated. There may be an AB difference of 6 degrees, a 30 degree Frankfort-mandibular angle, a mandibular incisal angle of 98 degrees, a 1.5 mm. pogonion and the patient is age 12. This could present a challenge. First, the four first molars are banded and impressions are taken for loop lingual arches-the upper with an acrylic palatal button (Fig. 4, Step a). These appliances are cemented at the second appointment. Now the lower lingual arch is extended by opening the U on each side slightly with ribbon arch pliers. In 3 weeks, the upper first and lower second premolars are banded. Upper laminated clover sections (Fig. 4, Step C) and lingual elastic modules are placed. The lower arch is extended at each appointment. The lower first molars will tip distally; the lower incisors are depressed and begin to align. The next addition is that of the lower 0.021 by 0.025 inch rectangular loop arch (E’ig. 4, Step B), which is seated in the lower second premolars and first molars and aligned gingivally in the anterior region. This anterior portion is tied up and through to the lingual arch with 0.012 inch ligature wire distal to each central incisor. The
Volunw Number
64 4
Fig. 4. Extraction of nique. Step A, Maxillary
Variations
upper second and lingual arch with
arch with rectangular loop Floater added to rectangular
labial loop
arch. arch.
lower acrylic Step
in edgewise
first premolars. palatal rest. C,
Laminated
biomechanics
Steps in treatment Step 6, Lower lingual clover
loop
section.
343
techloop Step
D,
is tied back to the molars. In a few months, with almost no discomfort to the patient or anchorage loss, the lower incisors will be depressed and level with the molar and second premolar. The lower incisor alignment will be corrected, the canines will have drifted back into the extraction space, and the incisors will move back to approximately a 90 degree mandibular incisal angle (Fig. 4, B). Had the canine been banded and retracted, anchorage would have been lost and the incisors would have moved forward. Measurements are now made for a rectangular loop arch, 0.021 by 0.025 inch, with a floater (Fig. 4, Step D) to move the canine roots distally, tying through again to the lingual arch. This is done to prevent elongation of the incisors. By this time the upper first premolars should be approximating the molar, since the clover section has been activated at each appointment. The sectional arches are now removed, the upper incisors are banded, and a 0.018 inch preliminary arch is placed for incisor alignment and leveling. When alignment is complete, a Broussard 0.017 by 0.025 inch arch (Fig. 5, Step E), with a stop and coil, is placed mesial to the upper first premolars. By this time the lower arch is fairly well stabilized to use for Class II anchorage if indicated. Some Class II elastic force may be needed to set the upper first molars and first premolars into occlusion or extraoral force may be used if indicated. Generally, there is lower anchorage to expend in these cases. The Broussard arch is now changed to a sliding ribbon section arch (Fig. 5, Step M). It is extended with an elastic module, the upper lingual arch is removed, and Class 11 5/1lsinch latex elastics are applied. The posterior teeth should now be in Class I relation, with the overbite corrected. The anterior section of the sliding section arch is now untied, and a canine-retractor spring is placed under it in the bracket slot (Fig. 5, Step G) . The arch is tied back, and arch
ig. 5. Steps Upper sliding
in treatment technique continued. Step E, Upper Broussard ribbon section with canine retractor. Step F, Lower rectangular
with floater added for canine root retraction. Step condensed. Step I, Canine banded. Laminated clover molars banded. Wildcat arch placed. Step K, Lower
arch.
Step loop arch
H, Canine retractor removed; arch vertical arch. Step J, Lower second laminated clover vertical arch.
Class II mechanics are continued. The canine will move distally, creating a space distal to the lateral incisors. Class II mechanics a,re discont,inued and the lower second molars are banded if sufficiently erupted (Fig. 5, Step J). A wildcat arch is placed and allowed to remain for 3 weeks. Measurement is made for a lower laminated clover vertical loop arch. We now wish to complete retraction of the canines. The laminated arch (Fig. 5, Step X) measured at the previous appointment, is placed, first opening the V loop anterior to the canine. Buccal teet,h are engaged first, and then the distal braeket of the canine is tied to the mesial leg extension of the clover loop. The bowed-out anterior portion is tied through to the lingual arch, and the arch is secured to the second molar tube. This gives a pull and a push to the canines, which are carried distally by the arch section between the two loops, When the space is closed and root paralleling is attained, the lingual arch is removed, incisors are
Variations
Fig. 6. Steps in treatment technique continued. finishing arch. Step M, Lower incisors banded, condensed. Step N, Lower laminated double-loop
Fig.
7. Class
I. Extraction
of upper
in edgewise biomechanks
Step 1, Upper laminated lingual arch removed, and finishing arch.
second
and
lower
first
345
double-loop laminated arch
premolars.
banded, and the laminated clover loop arch is replaced (Fig. 6, Step M) and tied back to complete incisor retraction. We generally finish the lower arch with the stabilized double-loop laminated arch (Fig. 6, S#tep N) . The upper arch is finished in a manner similar to the lower arch. The sliding ribbon section is removed, the upper canines are banded, and a laminated clover vertical loop arch (Fig. 5, Step I) is placed and tied back. Occipital or cervical traction may be used if necessary, or Class II elastics may be employed if mandibular anchorage loss is needed. The distal canine bracket is now tied to the mesial extension of the clover loop to ensure space closure. This will move the upper incisors slightly forward of the lower incisors to facilitate posterior occlusion. A laminated double-loop arch (Fig. 6, Step L) with labial crown torque is used for finishing. In debanding, the upper and lower incisor bands are removed first. Vertical elastics in the posterior region and horizontal elastics in
346
Carey
Fig. 8. Extreme were extracted.
Class
il,
DivisEon
i malocclusion
case
in
which
all
four
first
premoiars
the anterior region, canine to canine, are worn for 4 days. Following this, all bands except those on the upper first molars are removed, a lower canine-tocanine retainer impression is made, and cervical traction is applied to the maxillary molars. A 0.75 inch elastic is placed from molar to molar and the lower arch is left unattended. A lower canine-to-canine retainer is cemented 1 week later, and an impression is made for an upper retainer, which is placed in a day or two. The upper first premolar extraction treatment is similar to the treatment described and of shorter duration by approximately 3 months. In the maxillary arch, the first molars, second premoiars, and canines are banded. The lingual arch with acrylic palatal button is used. The canines are retracted with the laminated clover sections. Then a sliding section arch is engaged in the upper brackets with the anterior section free of the unbanded incisor teeth, The lingual arch with acrylic rest is removed, and Class II elastics and extraoral force are used to move the posterior teeth to occlusion. The incisors are banded, and a wildcat arch is placed to complete alignment. The wildcat arch is removed after several weeks, and a laminated clover vertical loop arch is placed to close all
Volume Number4
Variations
64
Fig.
9. Bimaxillary
protrusion
reduction.
in edgewise biomechanics
No
extraoral
force
347
used.
spaces. The double-loop laminated arch with labial crown torque is placed for finishing. In the mandibular arch, the treatment is the same as previously described. In Class II cases with closed deep-bites, me start moving the maxillary molars distally first with the headgear. No lingual arch is used. The maxillary incisors are then banded for a short time, and sliding ribbon section arch is placed. The headgear is continued, and Class II elastics are added to make the force constant until a Class I molar relation is established. The maxillary premolars are now banded and moved distally. The maxillary incisor bands are removed, and a stabilizing plate covering the occlusal surface of the posterior teeth is placed. The canines are now banded, and a laminated clover loop section is inserted. Class II elastics are discontinued while the canines are retracted. Now the maxillary incisors are rebanded, the plate is discarded, and a full laminated clover vertical loop arch is placed. Class II elastics and extraoral traction are now reinstituted, and alignment and space closing are completed. A tie is made from the mesial extension of the clover loop to the distal canine bracket to create a space distal to the lateral incisors to allow definite cuspal occlusion of the pasterior teeth.
348
am
Carey
9. ormosl.
October
1973
The finishing !aminated double loop with labial crown torque is placed and tied back. This space distal to the lateral incisors will close as the incisors are torqued. Three finished cases a.re shown in Figs. 7, 8, and 9 to demonstrate the three types of cases described in this article. It is believed that these concepts deserve some serious thought. Orthodontists everywhere may be agreeably surprised at the technical simplicity, the force control, and the time-saving dividends which will accrue from doing more thinking and less banding during the early stages of treatment. Ackno~~~ledgment editorial assistance
is made to Larry in the preparation
Xorrill of this
for the paper.
illustrations
and
to Rodney
Mathews
for
REFERENCES
1. Steiner, Cecil C.: Power storage and delivery in orthodontic appliances, AM. 3. @RTHOD. 39: 859-880, 1953. 2. Name, Hays N. : The removal of second premolars in orthodontic treatment, AM. J. ORTHOD. 35: 685696, 1949. 3. Carey, C. W.: Linear arch dimension and tooth size, AM. J. ORTHOD. 35: 7628-775, 1949. 4. Carey, C. W.: Principles and mechanics of treatment with the sliding twin section mechanism, AM. J. ORTHOD. 33: I-20, 1947. 5. Carey, C. W.: Diagnosis and case analysis in orthodontics, AM. J. ORTHOD. 38: 149-161, 1952. 6. Carey, C. W.: Treatment planning and the technical program in the four fundamental treatment forms, An%. J. ORTHOD. 44: 887-898, 1958. 7. Carey, C. TV.: Ljght force t,echnique combining the sliding section and Iaminated arches, AM. 5. ORTEOD. 52: 85-102, 1966. 1000
Welch
Rd.
64, Number
4, October,
1973
ORIGINdAL ARTICLES
Variations in edgewise biomechanics C. W. Palo
Alto,
Carey,
D.D.S.
Calif.
T
his concept is the culmination of ideas, philosophy, and treatment strategy put to the test first in the laboratory and then applied clinically. Many of th.e mechanical innovations had to be rejected, supplemented, or refined, and the treatment philosophy had to be revised as we became more concerned with new concepts and influenced by the work of contemporary researchers. The search for better treatment mechanics and strategy was inspired by the conviction that some of the current methods were not satisfactory, often cumbersome, inefficient in force control, and guilty of undesirable tooth movement. They involved unnecessary and often anchorage-weakening steps in early leveling for bracket engagement and mass movement of teeth locked together prematurely in ideal arch form, requiring the use of prolonged and extensive extraoral force. This latter procedure may result in a pseudocentric relationship. When dental arches are formed to fit each other before .they are positioned together anteroposteriorly, it is difficult to know when the correct centric relation has been established. The functional interdigitation of teeth should be subservient to the temporomandibular articulation. Iatrogenic temporomandibular joint problems may arise subsequent to treatment because of a malrelation between centric occlusion and centric relation, and frequently in Class II correction what is commonly referred to as a “creeping” or ‘Lend-on” cusp relation occurs. This is the beginning of a relapse precipitated by the tendency of the hinge axis of the masticatory mechanism to establish its own authentic occlusion. Clinical experience illustrates that in nonextraction cases the maxillary molars should be moved distally to occlusion with the mandibular molars first. Then the unbanded premolars are allowed to find their natural occlusion with the assistance of a light helical spring force. This creates an authentic occlusion 337
Am. b. Qrthod. October 1973
Fig.
1. Nonextraction.
Class
II,
Division
1.
and not the mesiaP creeping of the maxillary posterior teeth that formerly occurred when all of the teeth were banded prior to the Class II eorreetion. The principal policy of action is to move teeth with light forces in small units or to not move them at all but provide the lessened resistance in the path of desired movement so that they will move by themselves in a physiologic manner. It seems reasonable to assume that if teeth for which space is provided move into more desirable locations, they are more likely to stay there without restraint. Posterior corrections are made first, so that room may be provided for the anterior teeth. Consistent with this philosophy, with few exceptions, teeth should not be moved in any direction except toward the desired point of correction. Incisors should not be banded and aligned when they have no place to go. Also of questionable value is the use of Class III force to set up anchorage in Class II cases. When teeth are disturbed, and osteoclastie and osteoblastic action is in full force, their performance as an anchorage base for moving other teeth is weakened. Treatment should be started slowly, with simple mechanics and few bands, so as not to block natural progress and to permit gradual self-correction before adding to the appliances. The description of the mechanical approach to be advocated will be managed in three phases. The first is the distal movement of maxillary teeth in nonextraction cases with Class II cuspal relation, no mandibular discrepancy, and no extreme skeletal disharmony (Fig. 1). The mechanism used in the ma.xillary arch is the sliding ribbon section (Fig. 2, A). In the mandibular arch we use the loop lingual arch in conjunction with the rectangular loop arch (Fig. 2, C) , The principal advantage of the sliding section is to move the molars distally with the controlled light force of an 0.011 by 0.022 inch wire, extraoral traction, and some Class II elastics to keep the force 100 per cent constant. This arch does not expand in the molar region but acts as a guide wire to keep the posterior teeth in the soft medullary bone area. The molar correction is followed by the premolars, then the canines in turn, and finally the incisors. The reduction of the molars to a Class 1 relation should be
Volume Ntimber
64 4
Variations
Fig. 2. A and
B, New improved
tanguiar
loop
labial
retractor. Correction
F, Rectangular in alignment
arch
with
loop before
,iv% edgewise
biomechanics
339
sliding ribbon section suggested by Dr. Picard. C, Recloop lingual arch. 8), Plate premolar retractor. E, Cuspid G, Patient with crowded lower incisors. H, with Router. band
placement.
accomplished in a few months, the premolar retraction in 2 months, and the canine retraction in 1 month. Fig. 2, B shows a case under treatment as a typica exampIe. The upper appIiante is extended by placing an elastic module from the distal cleat to the mesial hook on each side. This is supplemented with a headgear 14 hours per day and light Class II elastics. When the molar has moved just bleyond Class I relation, the plate retractor with its helical finger springs (Fig. 2, D) is placed to move the premolars back. No Class II elastics are worn at this time. The canine retractor (Fig. 2, E) is then slipped beneath the anterior arch and the cleat is .tied back to the molar. The use of Class II elastics is resumed. The retractor
340
Carey
is then removed and use of a tie-back with elastic modules is continued for Fetraction of the incisors. The lower incisors are aligned and depressed to level off the arch with the loop lingual arch applying pressure on the cingulum of these incisors. If the orbicularis oris is strong, an 0.045 inch bumper arch is used labial to the incisors to exert distal pressure on the mandibular molars. The lower second premolars are banded after the molars have been uprighted, and a rectangular loop labial arch (Fig. 2, C) is placed and tied through to the lingual arch distal to the central incisors. This arch is set gingiva,lly in the anterior region and tied back periodically each time the loops on the lingual arch are opened. We have treated hundreds of cases with this same technique over the past 20 years. The sliding section arches are easily constructed by the technician. The parts are the two side hook se&ions of 0.021by 0.025 inch and the anterior section, 0.011 by 0.022 inch, which is held by an 0.036 inch spacer welded to the side section distal to the hook. The terminal two-way cleat is held in place by an 0.036 inch spacer. The arch gives an excellent opportunity to treat unilateral Class II conditions, since the opposite arch segment is not working against the side put in motion. This same mechanism is used in the maxillary arch in an extraction case to reduce the Class II malocclusion to Class I and open the bite. The second phase of this treatment concept is concerned with the management of the mandibular arch following extraction of the first premolars. It is a means, with minimal banding, of uprighting and then distally tipping the pasterior teeth, depressing the incisors, opening the b’ite, and permitting selfalignment of incisors and distal drift of canines. It is the most efficient method of handling extraction cases that we have used. The treatment is accomplished by the use of the loop lingual arch in conjunction with the rectangular loop arch (Fig. 2, C) which is used in two gauges, first the 0.017 by 0.025 inch and then 0.021 by 0.025 inch (Fig. 4, B) . The chief justification for the use of this combination of a labial and lingual arch is that, in performance, the posterior teeth seldome moved forward, while the unbanded incisors align and move back several degrees to the NB plane. The extraction space is reduced with the distal drift of the canines, and anchorage is thus conserved by minimizing the amount of canine retraction necessary for space closure. The lingual arch extension is synchronized with the labial arch retraction. Later, the floater (Fig. 2, P) is added to the rectangular arch to retract the root of he lower canine if necessary. A case under treatment (Fig. 2, G and H) demonstrates this operation. The third phase deals with the application and uses of the laminated arch. Laminated arches are split vertically 0.011 by 0.022 inch to form a DRII, 0.022 by 0.022 inch (double ribbon), or horizontally 0.0105 by 0.025 inch to form a, DEII, 0.021 by 0.025 inch (double edgewise). They are held together by spacer tubes, 0.030 inch, and adjustable stop hooks. The DEII, double-edgewise arches, are used extensively in our treatment program. They are used as sectional arches with a clover loop and stop for space closure (Fig. 3, A), in full arches, clover and V loop (Fig. 3, B) , in the final space-closing operation in extraction cases, and as a finishing arch with double helical loops (Fig. 3, C) . In explanation of the fabrication of these arches, let us take the finishing
Volunw Number
64 4
Fig. 3. A, Clover laminated finishing
Variations
loop laminated arch. D, Initial
section. 6, Clover step in laminated
in edgewise biomechanics
vertical loop arch fabrication.
arch.
C,
Double
341
loop
double-loop laminated arch as an example. It is made from the arch measurement taken with a wax strip which is softened and applied to the teeth from molar to molar and pressed gently against the brackets and attachments to make an imprint in the wax. The location of loops is marked by indenting the wax with a pencil point. This is transferred to a pad with a straight line on which the loops and arch length are indicated. The technician fabricates the arch in time for the next appointment. Ribbon arch pliers No. 142 with 0.022 by 0.028 inch slot and loop-forming pliers are used to form the arch. It is important that one end of the arch be open and the other end closed (Fig. 3, D). Three spacer tubes, 0.030 inch by 1 mm., are placed on the arch with the open end turned in the opposite direction so that the spacers will not slide off. A full 1Pinch length doubled over from the center is used to form the arch. In forming the loops, one should start at the closed end, being sure to work toward the open end with a spacer close to the working area. The open end permits freedom for shifting the lamina in forming the loops. Arches are always formed in a straight line before contouring, The contouring is done after the loop formation with the turret, as with a solid arch, and the offset and canine contour bends are made with the ribbon arch pliers. The open end is welded after the loops are formed. Use of the double-loop laminated arch (Fig. 3, C) is standard for our finishing procedures. In first-premolar-extraction cases the loops are located on the mesial and distal of the canine bracket. In the lower arch, the distal loop is made by starting with a gingival bend and the mesial loop is started with an occlusal bend. In the upper arch the procedure is reversed. The activated loops exert a continuous action on the canine roots to move their apices distally in extraction cases. Since the introduction of the module elastics, it is possible to omit the tieback hook and place a module from the molar hook to the distal loop. In the case of a second premolar or molar extraction, the first loop is in the extraction space and the second loop is mesial to the canine. In the lower arch, the mesial loop may also be formed by starting with a gingival bend to provide more efficient lingual root torque for the four anterior teeth. In the upper arch the reverse applies. When torque is incorporated in the arch wire, the action and power are stored in the mesial loops, and the arch wire is placed in the brackets easily and without excessive force or discomfort, It will generally require 6 weeks for
342
Am. J. Orrhod. October 1973
Carey
the incisors to assume the projected axial position directed by the laminated arch wire. The advantages of the laminated loop arch are ease of seating in the brackets which they fill, a resiliency which is eight times greater than that of the solid arch,l the continuous action to paralel roots of the canine and premolar, horizontal strength for arch form, and continuous action for effecting torque. Technical
application
of
the
four
principal
arrhes
in
fke
discrepancy
case
Preferentially, the upper second and lower first premolars are extracted in arch-length-deficiency cases. In such cases the discrepancy is usually confined to or greater in the mandibular than in the ma.xillary arch. If the discrepancy is not major, the removal of the first premolars may produce too much reduction and an unpleasant facial contour, It is almost impossible to “dish in” a face if the upper second premolars are removed. The upper first premolar, with its broad buccal plate of enamel, is a better anatomic specimen than the second premolar, and the esthetic appearance of the dental arch in the finished case is enhanced by its presence.% The remaining teeth have better articulation because the two smaller opposing teeth a.re removed instead of the smaller teeth below and the larger ones above. Contraindications to this selection would be in extreme discrepancies and Class II deep-bite cases. In these conditions, the first premolars are removed. Anchorage conservation and simplic.ity of appliance design and treatment procedures are the keynote to efficiency in the program plan for an esthetic and stable correction. If we have a discrepancy ca,se involving extraction of premolars, we do not approve of banding all available teeth and placing leveling arches. This procedure moves incisors labially, starts osteoclastie action in the entire peridontium, and weakens our precious anchorage, and we must now resort to external force to hold the posterior teeth back. Extraoral force in extraction cases should be used to reduce the Class II cuspal relation of the teeth and only very rareiy to reinforce anchorage. As an example, let us consider a Class I, deep-bite, 7.0 mm. discrepancy case in which the upper second and lower first premolars have been eliminated. There may be an AB difference of 6 degrees, a 30 degree Frankfort-mandibular angle, a mandibular incisal angle of 98 degrees, a 1.5 mm. pogonion and the patient is age 12. This could present a challenge. First, the four first molars are banded and impressions are taken for loop lingual arches-the upper with an acrylic palatal button (Fig. 4, Step a). These appliances are cemented at the second appointment. Now the lower lingual arch is extended by opening the U on each side slightly with ribbon arch pliers. In 3 weeks, the upper first and lower second premolars are banded. Upper laminated clover sections (Fig. 4, Step C) and lingual elastic modules are placed. The lower arch is extended at each appointment. The lower first molars will tip distally; the lower incisors are depressed and begin to align. The next addition is that of the lower 0.021 by 0.025 inch rectangular loop arch (E’ig. 4, Step B), which is seated in the lower second premolars and first molars and aligned gingivally in the anterior region. This anterior portion is tied up and through to the lingual arch with 0.012 inch ligature wire distal to each central incisor. The
Volunw Number
64 4
Fig. 4. Extraction of nique. Step A, Maxillary
Variations
upper second and lingual arch with
arch with rectangular loop Floater added to rectangular
labial loop
arch. arch.
lower acrylic Step
in edgewise
first premolars. palatal rest. C,
Laminated
biomechanics
Steps in treatment Step 6, Lower lingual clover
loop
section.
343
techloop Step
D,
is tied back to the molars. In a few months, with almost no discomfort to the patient or anchorage loss, the lower incisors will be depressed and level with the molar and second premolar. The lower incisor alignment will be corrected, the canines will have drifted back into the extraction space, and the incisors will move back to approximately a 90 degree mandibular incisal angle (Fig. 4, B). Had the canine been banded and retracted, anchorage would have been lost and the incisors would have moved forward. Measurements are now made for a rectangular loop arch, 0.021 by 0.025 inch, with a floater (Fig. 4, Step D) to move the canine roots distally, tying through again to the lingual arch. This is done to prevent elongation of the incisors. By this time the upper first premolars should be approximating the molar, since the clover section has been activated at each appointment. The sectional arches are now removed, the upper incisors are banded, and a 0.018 inch preliminary arch is placed for incisor alignment and leveling. When alignment is complete, a Broussard 0.017 by 0.025 inch arch (Fig. 5, Step E), with a stop and coil, is placed mesial to the upper first premolars. By this time the lower arch is fairly well stabilized to use for Class II anchorage if indicated. Some Class II elastic force may be needed to set the upper first molars and first premolars into occlusion or extraoral force may be used if indicated. Generally, there is lower anchorage to expend in these cases. The Broussard arch is now changed to a sliding ribbon section arch (Fig. 5, Step M). It is extended with an elastic module, the upper lingual arch is removed, and Class 11 5/1lsinch latex elastics are applied. The posterior teeth should now be in Class I relation, with the overbite corrected. The anterior section of the sliding section arch is now untied, and a canine-retractor spring is placed under it in the bracket slot (Fig. 5, Step G) . The arch is tied back, and arch
ig. 5. Steps Upper sliding
in treatment technique continued. Step E, Upper Broussard ribbon section with canine retractor. Step F, Lower rectangular
with floater added for canine root retraction. Step condensed. Step I, Canine banded. Laminated clover molars banded. Wildcat arch placed. Step K, Lower
arch.
Step loop arch
H, Canine retractor removed; arch vertical arch. Step J, Lower second laminated clover vertical arch.
Class II mechanics are continued. The canine will move distally, creating a space distal to the lateral incisors. Class II mechanics a,re discont,inued and the lower second molars are banded if sufficiently erupted (Fig. 5, Step J). A wildcat arch is placed and allowed to remain for 3 weeks. Measurement is made for a lower laminated clover vertical loop arch. We now wish to complete retraction of the canines. The laminated arch (Fig. 5, Step X) measured at the previous appointment, is placed, first opening the V loop anterior to the canine. Buccal teet,h are engaged first, and then the distal braeket of the canine is tied to the mesial leg extension of the clover loop. The bowed-out anterior portion is tied through to the lingual arch, and the arch is secured to the second molar tube. This gives a pull and a push to the canines, which are carried distally by the arch section between the two loops, When the space is closed and root paralleling is attained, the lingual arch is removed, incisors are
Variations
Fig. 6. Steps in treatment technique continued. finishing arch. Step M, Lower incisors banded, condensed. Step N, Lower laminated double-loop
Fig.
7. Class
I. Extraction
of upper
in edgewise biomechanks
Step 1, Upper laminated lingual arch removed, and finishing arch.
second
and
lower
first
345
double-loop laminated arch
premolars.
banded, and the laminated clover loop arch is replaced (Fig. 6, Step M) and tied back to complete incisor retraction. We generally finish the lower arch with the stabilized double-loop laminated arch (Fig. 6, S#tep N) . The upper arch is finished in a manner similar to the lower arch. The sliding ribbon section is removed, the upper canines are banded, and a laminated clover vertical loop arch (Fig. 5, Step I) is placed and tied back. Occipital or cervical traction may be used if necessary, or Class II elastics may be employed if mandibular anchorage loss is needed. The distal canine bracket is now tied to the mesial extension of the clover loop to ensure space closure. This will move the upper incisors slightly forward of the lower incisors to facilitate posterior occlusion. A laminated double-loop arch (Fig. 6, Step L) with labial crown torque is used for finishing. In debanding, the upper and lower incisor bands are removed first. Vertical elastics in the posterior region and horizontal elastics in
346
Carey
Fig. 8. Extreme were extracted.
Class
il,
DivisEon
i malocclusion
case
in
which
all
four
first
premoiars
the anterior region, canine to canine, are worn for 4 days. Following this, all bands except those on the upper first molars are removed, a lower canine-tocanine retainer impression is made, and cervical traction is applied to the maxillary molars. A 0.75 inch elastic is placed from molar to molar and the lower arch is left unattended. A lower canine-to-canine retainer is cemented 1 week later, and an impression is made for an upper retainer, which is placed in a day or two. The upper first premolar extraction treatment is similar to the treatment described and of shorter duration by approximately 3 months. In the maxillary arch, the first molars, second premoiars, and canines are banded. The lingual arch with acrylic palatal button is used. The canines are retracted with the laminated clover sections. Then a sliding section arch is engaged in the upper brackets with the anterior section free of the unbanded incisor teeth, The lingual arch with acrylic rest is removed, and Class II elastics and extraoral force are used to move the posterior teeth to occlusion. The incisors are banded, and a wildcat arch is placed to complete alignment. The wildcat arch is removed after several weeks, and a laminated clover vertical loop arch is placed to close all
Volume Number4
Variations
64
Fig.
9. Bimaxillary
protrusion
reduction.
in edgewise biomechanics
No
extraoral
force
347
used.
spaces. The double-loop laminated arch with labial crown torque is placed for finishing. In the mandibular arch, the treatment is the same as previously described. In Class II cases with closed deep-bites, me start moving the maxillary molars distally first with the headgear. No lingual arch is used. The maxillary incisors are then banded for a short time, and sliding ribbon section arch is placed. The headgear is continued, and Class II elastics are added to make the force constant until a Class I molar relation is established. The maxillary premolars are now banded and moved distally. The maxillary incisor bands are removed, and a stabilizing plate covering the occlusal surface of the posterior teeth is placed. The canines are now banded, and a laminated clover loop section is inserted. Class II elastics are discontinued while the canines are retracted. Now the maxillary incisors are rebanded, the plate is discarded, and a full laminated clover vertical loop arch is placed. Class II elastics and extraoral traction are now reinstituted, and alignment and space closing are completed. A tie is made from the mesial extension of the clover loop to the distal canine bracket to create a space distal to the lateral incisors to allow definite cuspal occlusion of the pasterior teeth.
348
am
Carey
9. ormosl.
October
1973
The finishing !aminated double loop with labial crown torque is placed and tied back. This space distal to the lateral incisors will close as the incisors are torqued. Three finished cases a.re shown in Figs. 7, 8, and 9 to demonstrate the three types of cases described in this article. It is believed that these concepts deserve some serious thought. Orthodontists everywhere may be agreeably surprised at the technical simplicity, the force control, and the time-saving dividends which will accrue from doing more thinking and less banding during the early stages of treatment. Ackno~~~ledgment editorial assistance
is made to Larry in the preparation
Xorrill of this
for the paper.
illustrations
and
to Rodney
Mathews
for
REFERENCES
1. Steiner, Cecil C.: Power storage and delivery in orthodontic appliances, AM. 3. @RTHOD. 39: 859-880, 1953. 2. Name, Hays N. : The removal of second premolars in orthodontic treatment, AM. J. ORTHOD. 35: 685696, 1949. 3. Carey, C. W.: Linear arch dimension and tooth size, AM. J. ORTHOD. 35: 7628-775, 1949. 4. Carey, C. W.: Principles and mechanics of treatment with the sliding twin section mechanism, AM. J. ORTHOD. 33: I-20, 1947. 5. Carey, C. W.: Diagnosis and case analysis in orthodontics, AM. J. ORTHOD. 38: 149-161, 1952. 6. Carey, C. W.: Treatment planning and the technical program in the four fundamental treatment forms, An%. J. ORTHOD. 44: 887-898, 1958. 7. Carey, C. TV.: Ljght force t,echnique combining the sliding section and Iaminated arches, AM. 5. ORTEOD. 52: 85-102, 1966. 1000
Welch
Rd.