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The Pollock appliance
The Pollock appliance Howard Kccnsns
I
H. Dukes, Citjy. Km.
B.S.,
D.D.S.,
M.S.D.
n an article cntitlod “Ilistoi~y lCcpcat,s Itself, l’art 11,” publishrd in 1968, issue of the AMERICAN JOURNAI, OF ORTHODONTICS, 1)~. II. ('?. Pollock, Sr., devotes two very short paragraphs to the Pollock appliance. Because of the brevity of this reference to the appliance which hc developed before World War I, many orthodontists may have missed its real impact. Dr. Pollock states : “This appliance has been found very satisfactory for expansion purposes. Therefore, it is hcrcwith again illustrated. It may bc called a modification of the original Jackson applia.ncc. It, is made of precious metal, however, and ~~.st be cemented into place with temporary cement only so that it can be quickly removed for readjustmc~nt; otherwise, it is of limitetl va1ue.“1 I’ollock refers to the appliance as a fiscd removable appliance. “Fixed, because it is cemented to place b> a temporary ccmcnt insofar as the anchoi bands are concerned. . . . Rcmornble bccnusc it may be quickly removed by tha operator, and the lingual base wire adjusted and manipulated similar to the technic cmploycd in the Jackson rcmovablc. . . . For these reasons, it is both temporarily fixed and at the same time ~~~noval~lc, at the discretion of the operator.“’ The appliance basically consists of two principal units : The lingual unit and the labial unit.S The lingual unit is a rccul’rcnt lingual arch soldered to the molar bands with forward estensiolls approximating the premolars and canines. It may also be constructed with JZrrshon half-round vertical tubes so that the operator can remove it without havin, 0 to recement the molar bands. The forward recurrent portion of the arch affords gentle, long-lasting action for controlled movement of the teeth ant1 cspansion of t,hc arch. “The labial arch by its contour, resilienre, l)ropcr adjustment, and specific design of the end segments may bc 11sct1to provide controlled, continuous or limited stimuli to the teeth. “The labial arch is adjusted so that when the arch is placed in the buccal tubes, it will have continuous energy being exerted within it to move buccally at both the right and left sides of the end segments of the labial arch. The the
734
August,
Pollock applimce
735
lingual arch provides sufficient anchorage so that the labial arch cannot move buccally in its effort to expend its energy, and, therefore, it will attempt to move distally through the buccal tubes until it has dissipated its energy, has l)~~cn r&rained by a stop in the labial arch, or becomes bound within the huccal tube.“3 The I’ollock recurrent lingual arch was originally used with the Angle ribbon arch, but later it was changed to a round 0.045 inch labial arch. To this heavy arch, an 0.020 inch auxiliary wire was attached to give “whip” action to thtl appliance. The smaller wire was soldered near the molar attachment, on one side and allowed to slide freely through a McCoy tube on the opposite side. This gave a continuous, gentle action while the heavy wire was being used as a stabilizing arch. The action of this small wire on the labial wire was usually l’ollock illustrates its USC 11sct1to move the incisor teeth posteriorly. IIOWCTC~, on a lingual arch (solderrd on one side and slidin g through a tube on the otlicr) with t,he opposite action-that of rno\-ing the incisors forward.Z Many orthodontists, using di&rcnt appliances, have been surprised to fin{1 that near the end of trcatmcnt the lower incisors have started to become spared. They failed to nntlerstnntl the principle of the “Pollock creep.” It is a basic physical principle that is present in ~11 resilient orthodontic
Fig.
1.
Case
expansion
10:
367-369,
treated was
highly 1924.)
with
Pollock
expansion
recommended.
(From
appliance Pollock:
in
1922
International
and
1923
Journal
when of
growth
Orthodontia
736
LJukes
wires, whether they are 0.008 or 0.050 inch in diameter. Practice bccomcs more pleasant when we understand the inherent action of each of the wires that \ve use daily. Pollock states further : “It enjoys the same principles in physics and dynamics as do the bow and bow string-a spring trying to release itself, making an effort to assume its normal position, being arrested, however, in its effort by its moorings (the teeth) .“:! Pollock described the appliance at greater length in a series of articles on “Elementary Orthodontic Technic” published in 1923 and 1024, in the ESTERNATION.~L Jourz~ar, OF OKTHODONTIB, ORan SURGERY AND RADIOGRAPHY. In discussing labial arches, he states : “The plain wire x-ithout, nuts or threatls whatsoever still has a place, for the reason that by placing a lateral spring tension in the wire (expansion) it makes a distinct effort to creep backward
Fig. 2. The Pollock expansion treatment International Journal
Fig. 3. Pollock appliance Journal of Orthodontia
expansion appliance, was recommended. of Orthodontia 10:
which was used profusely Only temporary cement was 166- 170, 1924.)
used for vigorous expansion 10: 367-369, 1924.)
in 1923.
[From
at the time when used. (From Pollock:
Pollock:
International
Pollock applimce
Fig. 4. Backward Pollock (8) is placed in the buccal the
dental
the
buccal
Fig.
5.
arch
position
to
position
When
a
small
attachments
and
D. Note
how
far
straight the
(A)
wire
allowed
to wire
slide has
or
an
freely,
expanded it will
extended
arch
move
distally
from
through
attachments.
Forward
attachments to
(C)
creep. tube
737
Pollock and
B.
allowed
creep. to
When slide
a contracted freely,
it will
arch move
wire forward
(A)
is from
placed the
in dental
the
buccal arch
(C)
738
Dukes
Am.
.T. Orthodontics J?cm? 1969
through the buccal tubes, thereby exertin g force upon the anterior teeth. By such Cffol’t, also, lateral energy is cxertcd upon t,he molar, premolar and canine region.“’ The buccal molar brackets arc attached to the buccal surfaces of the molar bands of all fixed appliances in such a manner that there is a divergent angulation from front to back. Hence, when a small resilient straight arch wire or a heavier expanded arch wire is placed in the molar attachments and allowed to slide freely, the incisor teeth will be moved posteriorly. All of Dr. Pollock’s students seemed to understand this a&on, but some of them missed the impact of the next paragraph concerning the “Pollock creep.” “In a like manner, if the plain unthreaded wire is contracted and then forcetl through the tubes, it exerts a distinct forward movement,, tries to creep out of the tubes, SO to speak. This force may also be utilized in moving the antcriol teeth forward, by ligating the anterior teeth by either ligature or brackets.“-L This is the action that is not understood by the orthodontist when he finds spacing of the incisors. Even a supposedly passire “ideal” arch may have enough action, if it is not securely ligated, to cause slight forward IIWVC~CI~~ oi' the incisors, The forward creep may bc utilized unilaterally, if this be desirable, by securely fastening one end so that forward movement cannot occur and allowing the opposite end to slide freely t,o move the lateral incisor and canine arca forward. Conversely, a light resilient straight wire can be stopped mesial to the buccal attachment on one side to move the opposite lateral incisor and canine posteriorly. The action of the “Pollock creep” appliance is valid in any size of wire. An 0.010 inch straight wire placed in the labial brackets and allowed to slide freely through the molar attachments will move the incisors posteriorly and the molars buccally. Conversely, the contoured, contracted labial arch will cause the incisors to move forward, unless the creeping action is stopped by tying the arch to the molars or by counteracting its action by pressure in the opposite: direction. Hence, in prescribing the proper amount of pressure, this important built-in action of the wires that we use daily must bc considered. REFERENCES
1. Pollock, 536-539 2. pollock,
H. C.: History repeats itself--Part I :artl P:\rt 11, AM. J. ~RTIIOI~~~N’~~I~~S 54: ; 561.565, 1968. H. C. : &Iodification of the fixed remov:~l~lc type’ of ort,hodontic :lppli:~u~, 1S’I’. .I. ORTHODOX-TIA 16: 737-743, 1930. The Pollock fixed and removable appliance and its Alization in 3. Deynan, Edward V.: orthodontic treatment, thesis, Dubuque, Iowa, 1954. 4. Pollock, H. C.: Elementary orthodontic technic, IXT. J. ORTHODONTIA 9: 120-121, 207-210, 282.287, 364.369, 453.459, 527.531, 770.772, 840-846, 929-936, 1923; 10: 38-41, 166-171, 364-369, 1924. 5. Pollock, H. C.: An orthodontic appliance, bring :I cum1 Amtion of principles involved in the lingual appliance, ribbon arch, and expansion RTCII, TNT. .T. ORTHODOKTIA 6: 573.578, 19m.
I
H. Dukes, Citjy. Km.
B.S.,
D.D.S.,
M.S.D.
n an article cntitlod “Ilistoi~y lCcpcat,s Itself, l’art 11,” publishrd in 1968, issue of the AMERICAN JOURNAI, OF ORTHODONTICS, 1)~. II. ('?. Pollock, Sr., devotes two very short paragraphs to the Pollock appliance. Because of the brevity of this reference to the appliance which hc developed before World War I, many orthodontists may have missed its real impact. Dr. Pollock states : “This appliance has been found very satisfactory for expansion purposes. Therefore, it is hcrcwith again illustrated. It may bc called a modification of the original Jackson applia.ncc. It, is made of precious metal, however, and ~~.st be cemented into place with temporary cement only so that it can be quickly removed for readjustmc~nt; otherwise, it is of limitetl va1ue.“1 I’ollock refers to the appliance as a fiscd removable appliance. “Fixed, because it is cemented to place b> a temporary ccmcnt insofar as the anchoi bands are concerned. . . . Rcmornble bccnusc it may be quickly removed by tha operator, and the lingual base wire adjusted and manipulated similar to the technic cmploycd in the Jackson rcmovablc. . . . For these reasons, it is both temporarily fixed and at the same time ~~~noval~lc, at the discretion of the operator.“’ The appliance basically consists of two principal units : The lingual unit and the labial unit.S The lingual unit is a rccul’rcnt lingual arch soldered to the molar bands with forward estensiolls approximating the premolars and canines. It may also be constructed with JZrrshon half-round vertical tubes so that the operator can remove it without havin, 0 to recement the molar bands. The forward recurrent portion of the arch affords gentle, long-lasting action for controlled movement of the teeth ant1 cspansion of t,hc arch. “The labial arch by its contour, resilienre, l)ropcr adjustment, and specific design of the end segments may bc 11sct1to provide controlled, continuous or limited stimuli to the teeth. “The labial arch is adjusted so that when the arch is placed in the buccal tubes, it will have continuous energy being exerted within it to move buccally at both the right and left sides of the end segments of the labial arch. The the
734
August,
Pollock applimce
735
lingual arch provides sufficient anchorage so that the labial arch cannot move buccally in its effort to expend its energy, and, therefore, it will attempt to move distally through the buccal tubes until it has dissipated its energy, has l)~~cn r&rained by a stop in the labial arch, or becomes bound within the huccal tube.“3 The I’ollock recurrent lingual arch was originally used with the Angle ribbon arch, but later it was changed to a round 0.045 inch labial arch. To this heavy arch, an 0.020 inch auxiliary wire was attached to give “whip” action to thtl appliance. The smaller wire was soldered near the molar attachment, on one side and allowed to slide freely through a McCoy tube on the opposite side. This gave a continuous, gentle action while the heavy wire was being used as a stabilizing arch. The action of this small wire on the labial wire was usually l’ollock illustrates its USC 11sct1to move the incisor teeth posteriorly. IIOWCTC~, on a lingual arch (solderrd on one side and slidin g through a tube on the otlicr) with t,he opposite action-that of rno\-ing the incisors forward.Z Many orthodontists, using di&rcnt appliances, have been surprised to fin{1 that near the end of trcatmcnt the lower incisors have started to become spared. They failed to nntlerstnntl the principle of the “Pollock creep.” It is a basic physical principle that is present in ~11 resilient orthodontic
Fig.
1.
Case
expansion
10:
367-369,
treated was
highly 1924.)
with
Pollock
expansion
recommended.
(From
appliance Pollock:
in
1922
International
and
1923
Journal
when of
growth
Orthodontia
736
LJukes
wires, whether they are 0.008 or 0.050 inch in diameter. Practice bccomcs more pleasant when we understand the inherent action of each of the wires that \ve use daily. Pollock states further : “It enjoys the same principles in physics and dynamics as do the bow and bow string-a spring trying to release itself, making an effort to assume its normal position, being arrested, however, in its effort by its moorings (the teeth) .“:! Pollock described the appliance at greater length in a series of articles on “Elementary Orthodontic Technic” published in 1923 and 1024, in the ESTERNATION.~L Jourz~ar, OF OKTHODONTIB, ORan SURGERY AND RADIOGRAPHY. In discussing labial arches, he states : “The plain wire x-ithout, nuts or threatls whatsoever still has a place, for the reason that by placing a lateral spring tension in the wire (expansion) it makes a distinct effort to creep backward
Fig. 2. The Pollock expansion treatment International Journal
Fig. 3. Pollock appliance Journal of Orthodontia
expansion appliance, was recommended. of Orthodontia 10:
which was used profusely Only temporary cement was 166- 170, 1924.)
used for vigorous expansion 10: 367-369, 1924.)
in 1923.
[From
at the time when used. (From Pollock:
Pollock:
International
Pollock applimce
Fig. 4. Backward Pollock (8) is placed in the buccal the
dental
the
buccal
Fig.
5.
arch
position
to
position
When
a
small
attachments
and
D. Note
how
far
straight the
(A)
wire
allowed
to wire
slide has
or
an
freely,
expanded it will
extended
arch
move
distally
from
through
attachments.
Forward
attachments to
(C)
creep. tube
737
Pollock and
B.
allowed
creep. to
When slide
a contracted freely,
it will
arch move
wire forward
(A)
is from
placed the
in dental
the
buccal arch
(C)
738
Dukes
Am.
.T. Orthodontics J?cm? 1969
through the buccal tubes, thereby exertin g force upon the anterior teeth. By such Cffol’t, also, lateral energy is cxertcd upon t,he molar, premolar and canine region.“’ The buccal molar brackets arc attached to the buccal surfaces of the molar bands of all fixed appliances in such a manner that there is a divergent angulation from front to back. Hence, when a small resilient straight arch wire or a heavier expanded arch wire is placed in the molar attachments and allowed to slide freely, the incisor teeth will be moved posteriorly. All of Dr. Pollock’s students seemed to understand this a&on, but some of them missed the impact of the next paragraph concerning the “Pollock creep.” “In a like manner, if the plain unthreaded wire is contracted and then forcetl through the tubes, it exerts a distinct forward movement,, tries to creep out of the tubes, SO to speak. This force may also be utilized in moving the antcriol teeth forward, by ligating the anterior teeth by either ligature or brackets.“-L This is the action that is not understood by the orthodontist when he finds spacing of the incisors. Even a supposedly passire “ideal” arch may have enough action, if it is not securely ligated, to cause slight forward IIWVC~CI~~ oi' the incisors, The forward creep may bc utilized unilaterally, if this be desirable, by securely fastening one end so that forward movement cannot occur and allowing the opposite end to slide freely t,o move the lateral incisor and canine arca forward. Conversely, a light resilient straight wire can be stopped mesial to the buccal attachment on one side to move the opposite lateral incisor and canine posteriorly. The action of the “Pollock creep” appliance is valid in any size of wire. An 0.010 inch straight wire placed in the labial brackets and allowed to slide freely through the molar attachments will move the incisors posteriorly and the molars buccally. Conversely, the contoured, contracted labial arch will cause the incisors to move forward, unless the creeping action is stopped by tying the arch to the molars or by counteracting its action by pressure in the opposite: direction. Hence, in prescribing the proper amount of pressure, this important built-in action of the wires that we use daily must bc considered. REFERENCES
1. Pollock, 536-539 2. pollock,
H. C.: History repeats itself--Part I :artl P:\rt 11, AM. J. ~RTIIOI~~~N’~~I~~S 54: ; 561.565, 1968. H. C. : &Iodification of the fixed remov:~l~lc type’ of ort,hodontic :lppli:~u~, 1S’I’. .I. ORTHODOX-TIA 16: 737-743, 1930. The Pollock fixed and removable appliance and its Alization in 3. Deynan, Edward V.: orthodontic treatment, thesis, Dubuque, Iowa, 1954. 4. Pollock, H. C.: Elementary orthodontic technic, IXT. J. ORTHODONTIA 9: 120-121, 207-210, 282.287, 364.369, 453.459, 527.531, 770.772, 840-846, 929-936, 1923; 10: 38-41, 166-171, 364-369, 1924. 5. Pollock, H. C.: An orthodontic appliance, bring :I cum1 Amtion of principles involved in the lingual appliance, ribbon arch, and expansion RTCII, TNT. .T. ORTHODOKTIA 6: 573.578, 19m.