SPECIAL ARTICLES
Crozat appliance therapy for discrepancy problem
an
arch-length
Marshall Parker, DDS* Knoxville, Tenn.
The case involved a white male subject, aged 10 years 6 months, with a Class I molar relationship complicated by a deep overbite and impaction of all four permanent canines, which were completely blocked out of the arches. The growth rate of the arches was found to be abnormal, and there was premature loss of the deciduous teeth. Over a period of approximately 5 years, with intermittent pauses to allow growth to catch up with treatment, the Crozat removable appliance was used to help establish the arch form and correct the plane of occlusion. (AM J ORTHOP DENTOFAC ORTHOO 1991 ;99;64-73.)
CASE REPORT
Casts
The case involved a multistage treatment for malocclusion that was started in the mixed-dentition phase and completed in the permanent dentition. The patient, aged 10 years 6 months, was referred by his father, a physician specializing in plastic surgery, whose only admonition was "Don't even think about extracting any of my boy's teeth." At his initial visit, on Oct. 12, 1973, the patient had a Class I molar relationship, complicated by a deep overbite and impaction of all four permanent canines, which were completely blocked out of the arches. Three of his deciduous second molars had already erupted.
Casts revealed mesiolingual rotation of the maxillary and mandibular first molars (Fig. 2). Arch form was determined by positioning the casts so that the incisors were in a relatively desirable position. The anteroposterior relation of the molars and premolars was then noted, and a relative idea of how much rotation would be necessary to cause the upper molars to fit with the lower molars was attained. Precise arch form measurements were taken? Both of the maxillary canines, which were labially impacted, had no room to erupt. The mandibular right lateral incisor was touching and overlapping the mesial surface of the first premolar, completely obstructing the path of eruption of the lingually impacted canine. The mandibular left canine was partially trapped under the distal surface of the left lateral incisor. Both deciduous mandibular second molars and permanent first molars had already erupted.
Photographs Pretreatment frontal and lateral photographs (Fig. l) show the patient with lips closed in a relaxed position, with no asymmetry.
Radiographs *A Diplomateof the AmericanBoard of Orthodontics. 814114619
The Panoral radiograph showed severely crowded arches and a mixed-dentition development, with all permanent teeth
Fig. 1. Pretreatment facial photographs of patient at age 10 years 3 months.
64
Vohtme 99 Number 1
Special article
present. The cephalogram rcvcaled an adequate upper airway. The maxillary incisors were scvcrcly rctroinclined. The mandibular plane was fiat. The facial axis was growing at an angle that could be expected to favor horizontal arch development. Cephalometric tracings and analysis are shown in Fig. 3 and Table I.
HISTORY AND GENERAL CLINICAL PICTURE
The patient had no additional abnormal medical or dental history, and no aberrant habits were noted. Cooperation during treatment was typical for a boy of the patient's age. The probable factors affecting the patient's dental malocclusion were genetic, developmental, and functional. The
Fig. 2. Pretreatment study models of patient at age 10 years 3 months. Note arch length deficiency.
BASIC Status X-Ray
CEPHALOMETRIC
Pratraatmont
Ag~/Sex 10. 3
65
Male
10-12-73
Q
Fig. 3. Initial cephalometric tracing.
ANALYSIS
66
Parker
Am. J.
T a b l e I, O L I b a s i c c e p h a l o m e t r i c a n a l y s i s ( p r e t r e a t m e n t ) f o r p a t i e n t at a g e 10.3 y e a r s
Variable
Norm
tI
Patient
Difference - 1.78 ° 5.23 ° 5.48 ° -4.60 ° - 5.92 ° 1.32 ° - 4.59 ° - 10.60 ° - 2 . 3 5 mm - 8.98 ° - 2 . 9 6 mm < ! . 1 9 mm 19.39 o 2.25 ° 4.83 ° - 2 . 9 5 mm Within range Within range 1 . 3 0 mm - 1.59 o Within range Within range Within range 6.57 ° - 6.44 ° 1.02 ° - 8.92 °
SN to horizon FH to horizon SN to FH SNA SNB ANB SND
7° 0° 5° 82 ° 80 ° 2° 76 °
5.22 ° 5.23 ° 10.48 ° 77.400 74.08 ° 3.32 ° 71.41 °
I / to N A
22"
11.40 °
1 / to N A
/ I to NB /1 to NB /1 to APO 11 to fi ANS-PNS to SN Occ to SN GoGn to SN GoGn GoCo GoGn minus GoCo GoGn to GoCo /M lip to E line M / l i p to E line Facial axis IMPA FMA FMIA Z angle
4 mm
25 ° 4 mm - 1 to 3 mm I31 ° 8° 14° 32 ° 70-86 mm 49-65 mm 21 mm 123 ° - 4 to 0 mm - 3 . 7 to 0.28 mm 87-93 ° 87 ° 25 ° 68 ° 78 °
Rotation center is 15 mm from incisal tip. IMPA is adjusted to a boundary limit of 95 °. Estimated crowding is
1 . 6 5 mm 16.02 ° 1.04 mm - 2 . 1 9 mm 150.39 ° 10.25 ° 18.83 ° 29.05 ° 73.10 mm 50.80 mm 22.30 mm 121.41" - 1.72 mm - 1.22 mm 91.77 ° 93.57 ° 18.56 ° 69.02 ° 69.08 °
/1 MD/FL1 × 2 /2 MD/FL2 x 2 Sagittal diagnosis: Maxillary incisor retroinclined
I
Adjusted value
75.62 ° 72.30 ° 69.63 °
12.03 °
15.33 ° 72.25 ° 72.31 °
10.76 mm
Resolution of tooth to arch size descrepancy with flattened curve of Spee: IMPA (Referenced to Down's occlusal plane) IMPA (Referenced to new molar--incisor plane)
111213 to 112131
Orthod. Dentofac. Orthop. January 1991
118.20 ° 118.07 °
2.490 mm excess width 1.665 mm excess width .7679 mm excess width
Adapted from a table by Orthodontic Logic, Inc., ~ 1987.
patient's facial characteristics were very similar to those o f his father. Relative growth rate o f the arches in the dentofacial region appeared to be abnormal, and a local functional c o m p o n e n t affecting this case was premature loss o f deciduous teeth.
TREATMENT PLAN The initial treatment plan was first to attempt the necessary arch change by correcting the axial positions o f the permanent first m o l a r s ? This approach was based on the patient's chronological and developmental age, as well as on his dental age. The first molars erupt first, and therefore must be corrected first. It was a s s u m e d that significant space could
be gained by the correction o f abnormally rotated molars. ~ T h e Crozat removable appliance was used for this purpose. As the arch f o r m developed, deciduous teeth exfoliated, and g r o w t h continued d o w n w a r d and forward, the extraction o f p e r m a n e n t teeth b e c a m e unnecessary because the teeth aligned and leveled themselves. The correction o f the plane o f occlusion and the creation o f normal intermaxillary dental arch relation occurred coincidentally with the establishment o f the arch form, aided by horizontal growth. Simple reciprocal intramaxillary anchorage, 2 obtained by a.ctivating the appliance, prevented mesial migration of the first permanent molars as the patient's face g r e w d o w n w a r d and forward. Adjustment o f the appliance exerted force out-
Volume 99 Number I
Special article
Fig. 4. Posttreatment facial photographs of patient at age 16 years 5 months.
Fig. 5. Posttreatment study models of patient at age 16 years 5 months.
67
68 Parker
Am. J. Orthod.Dentofac.Orthop. January 1991
ANALYSIS
CEPHALOMETRIC
BASIC
Stotus Post-treotm~nt A g ~ / S e × 16. 5 N o l ~
X-Roy
7B. 3 4 7 7 . 48
12-2B-Tg
15.59 64. g I
_J "V Fig. 6. Posttreatment cephalometric tracing.
Table II. OLI basic cephalometric analysis (posttreatment) of patient at age 16.5 years
Variable
[
Norm
]
Patient
[
Difference
S N to h o r i z o n
7°
4.67 °
F H to h o r i z o n
0°
4.37 °
4.37 °
SN to FH
5°
9.07 °
4.07 °
I
Adjustedvalue
- 2.33 °
SNA
82 °
78.34 °
- 3.66 °
76.01"
SNB
80 °
77.48 °
- 2.52 °
75.15 °
ANB
2o
0.86 °
- 1.14 °
76*
76.06 °
0.06 °
22"
24.94 °
2.94 °
SND I/to
NA
1/to
NA
4 mm
/ 1 to N B / 1 to N B / 1 to A P O
5.88 mm
25 ° -
i/toll
22.14 °
1.88 m m - 2.86 °
4 mm
3.28 mm
-0.72 °
l to 3 m m
1.65 m m
Within range
131 °
133.21 °
8°
8.56 °
0.56 °
14 °
11.95 °
- 2.05 °
A N S - P N S to S N O c c to S N G o G n to S N
73.73 °
32 °
2.21 °
24.66 °
10.89 °
- 7.34 °
GoGn
70-86 mm
81.01 m m
Within range
GoCo
49-65 mm
62.49 mm
Withih range
21 m m
18.51 m m
GoGn minus GoCo G o G n to G o C o / M lip to E line M/lip
to E line
123 ° -4 -4.9
115.89 °
to 0 m m to - . 9 8
mm
-2.49
mm
- 7.11 °
-2.99
mm
Within range
-3.33
mm
Within range
Facial axis
87-93 °
IMPA
87"
100.65"
13.65 °
FMA FMIA
25 ° 68 °
15.59 ° 64.91 o
-9.41 ° - 3.09 °
67.29 °
Z angle
78 °
75.97 °
- 2.03 °
78.34 °
95.09"
>2.09 13.22 °
Volume 99 Number 1
Special article
Croniol 07-01-63
SupQ~position
Bas@
H
' ""'- ....
SN AT S Ter'm I r'~e 4
Ncas i otq
354.77
^~ga.
_ ! ~..s. L2z_La-._Lg__pe_._t_L
.-"
ttt
) i
l
°_.
i
.~ . . . . . . . . . . . . . . . . . . . . . . . "-'=-'~¢~.-~t. . . . . . . . . . . . . .
.72--~
ts
Fig. 7. Superimposed pre- and posttreatment cephalometric tracings. Note downward and forward growth pattern.
Table III. OLI basic cephalometric analysis (final posttreatment) at age 22.1 years
r ,b,e
I
No..,
I
l
O r.nce
I
Adjusted value
S N to h o r i z o n
7°
9.85 °
2.85 °
FH to horizon
0°
0.87 °
0.87 °
S N to F H
5°
9.04 °
4.04*
SNA
82 °
78.90 °
- 3.10 °
81.74 °
SNB
80 °
78.44 °
- 1.56 °
81.28 °
ANB
2°
0.46 °
- 1.54 °
SND
76 °
76.86 °
0.86 °
1/to NA
220
25.61 °
3.61 °
1/to NA
4 mm
/ 1 to NB
25 °
/ 1 to N B / 1 to A P O
6.41 m m 22.02 °
4 mm
1 / to / 1 A N S - P N S to S N O c c to S N G o G n to S N
2.41 m m - 2.98 °
2.92 mm
- 1 to 3 m m
1.22 m m
- 1.08 m m Within range
131 °
133.06 °
2.06 °
8°
8.43 °
0.430
14 °
11.25 °
-2.75 °
32 °
24.02 °
70-86 mm
83.68 mm
Within range
GoCo
Within range
49-65 mm
64.32 mm
GoGn minus GoCo
21 m m
19.36 m m
G o G n to G o C o
123"
M/lip
to E line
Facial a x i s
-4 -5.8
115.89 °
to 0 m m to - 1 . 8 87-93 °
mm
- 1.64 m m - 7.11 °
-3.87
mm
Within range
-3.99
mm
W i t h i n .range
96.28 °
558 °
-7.98 °
GoGn
/ M l i p to E line
79.70 °
>3.28
1MPA
87 °
100.21 °
13.21 °
FMA
25 °
14,98 °
- 10.02 °
FMIA
68 °
65.95 °
- 2.05 °
13.85"
Z angle
78 °
76.54 °
- 1.46 °
67.08 ° 77.67 °
69
70
Parker
A m . J. Orthod. Dentofac. Orth January 1
Mox
i 1 1 ory
Occ ,.;
1 usa
:, ,
/
,,, ..:/ l~,:lexS~9 DQV.O
^nchoe'
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-
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Post.
PP3
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I
ll
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:, ,;
~(,~" I
,
,
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\...,
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,,
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'.'/.
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• j. ~r/J~l.T-~'(y:e~,,.%
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,., . . . . . . ,.,
"
~~~-~
S p i n e '-'" [,/'~, \ /
....... "
,7g.g9
1 .qmmm ,
:"
,
,. -..,
,
,
,
A Mondibu1
or-"
Ocolusal.qrom
07-01-63 tnde~sn s Da~a
~.-.. . . ~ ,~,.
.
D POINT-MC69 AT D POINT Anchor 49 0 Point. re.~Inu, 50 Mond. ^.~,. 20g. 55
Corpus 60 LQ'~t
Rlsht 10.3 10-12-73 PretreotmGnt
. .16.5 . . . . . . . . 1. .2. .-.2. .8.-. 7. .g. P o l t - t r Q a t m Q n t
Radla]e
L_.]
~..~.. -,,~i I ,,:~ ...___ ~: ........./"J ~ j
I
--
-," '
_~~,.)
:,/
,'"' 2)
B Fig. 8. A, Maxillary occlusogram. B, Mandibular occlusogram; pre- and posttreatment superimpositions show tooth position changes.
Voh,me 99
Special article
Number 1
71
Fig. 9. Final posttreatment facial and intraoral photographs of patient at age 22 years 1 month.
ward or laterally, as well as distally, to eliminate the anterior constriction of and possible mandibular entrapment from the retroinclined maxillary incisors. When the appliance was adjusted, there was a tendency for it to extricate itself from the teeth. This phenomenon aided the vertical growth of the posterior teeth. The posterior movement was augmented or increased by the addition of lingual springs at the gingival margins of the upper and lower retroinclined incisors. TREATMENT PROGRESS
The upper and lower appliances were placed on separate occasions, 1 week apart, so the patient could become accustomed to one appliance before the second one was placed. After I month when the patient had become fully accustomed to the appliances, rotational adjustments were made in both appliances to rotate the molars. Six weeks later, lapping sweep springs were soldered to the ends of the lingual arms of the lower appliance and contoured so that they touched the cingula of all the incisors and ended at the canines. At this same
appointment, another rotational adjustment was made in the maxillary appliance. During the next 8 months, only one rotational adjustment was made in each appliance. The patient continued to wear his appliances, however. This interval was a planned rest period, in which the patient had to grow to catch up with the adjustments. During this time the remaining deciduous teeth were lost. Throughout treatment, the patient was seen at intervals of 5 or 6 weeks. One year after treatment had been initiated, elastic hooks and Class I1 5/16-inch, 3.5-ounce latex elastics were added. Much of the malocclusion had already begun to correct itself. The molars'were in neutrocclusion, and space was beginning to develop for the canines. During the next 2 years, two additional rotational adjustments were made. During sleeping hours, the patient wore Class II elastics, and again, there were planned rest periods to allow growth to catch up with the adjustment. After 3V2 years, there was enough room for the maxillary canines to
72
Parker
Am. J. Orthod. Dentofac. Orthop. January 1 9 9 1
OPomiol
Bos@
SupQmpos
ition
07-01-6:9 l ~ d * N I m ~ O=~a
SN AT S A~¢ho~ 6 Terminus 4 ^~.
Sel 1o
Nosion 354.77
10.3 10-12-73 P r i n t
]6.5
12-2fl-79
22.1CB-I3-B5
FINAL
•'J'l :
~
;
~-J/V ,
Fig. 10. Superimposed pre-, post-, and final-observation cephalometric tracings.
erupt. A finger spring was soldered to the buccal arm above the elastic hook and bent to engage the mesial surface of the upper canines. The patient continued to wear elastics full time. The mandibular canines erupted without additional help. When all the canines were in normal relation, the patient was instructed to wear his elastics at night only but to wear the appliances all the time. By Sept. 5, 1978, he was asked to wear the appliances at night only. He was seen at 3-month intervals until Dec. 28, 1979, when posttreatment records were taken. Retention was not a problem; it occurred coincidentally with the progression of treatment. Time and function helped to produce the desired result.
RESULTS Photographs Both lateral and frontal photographs showed a pleasing face in which the teeth were in harmony with the musculature when the lips were in repose (Fig. 4).
Casts Posttreatment casts showed all the teeth present and in a Class I relationship. The dental midline matched that of the face, and there was good interdigitation (Fig. 5).
Radiographs No root resorption was evident on the panoramic radiographs. Axial inclination was normal. The posttreatment
cephalometric analysis showed that the maxillary incisors were no longer retroinclined (Fig. 6 Table II). No auxiliary attachments had ever been worn on the labial surfaces of the maxillary incisors. The cranial base superposition (Fig. 7) revealed that as the face grew downward and forward, the molars were rotated and kept from erupting quite as fast as the rest of the teeth (Fig. 8, A and B). Four impacted third molars were extracted on August 13, 1981. The maxillary and mandibular occlusograms revealed that first and second molars were not driven distally to impact the third molars (Fig. 8, A and B). The mandibular occlusogram showed that the arch had not expanded in the canine area. In fact, the permanent canines were lingual to the position of the premolars that had formerly occupied the space. Total treatment time, including pauses for growth and retention, was approximately 5 years. The procedure was to treat and pause, treat and pause, treat and pause, always allowing growth to catch up with treatment. An observation of particular interest is that a greater amount of tooth movement took place during the planned rest intervals than during continuous active treatment. When the molars are rotated distobucally, they must assume a position in a wider portion of the arch as growth takes place in a downward and forward direction. In this case, all four first molars were originally ovcrrotated, causing the central groove to be awry. This situation was corrected during treatment by the addition of auxiliary wires attached to the body wire and resting on the second molars.
Volume 99 Number 1
FINAL EVALUATION
The final posttreatment records were taken 6 years later, on Aug. 13, 1985 (Figs. 9, 10, and Table III). Retention was not a problem, since time and function helped to produce a pleasing and harmonious result. COMMENTARY
The Crozat philosophy is based on the premise that occlusion is not static but is a dynamic condition throughout life. Since the greatest amount of change occurs during the first 25 years of life, a fixed or removable retainer that does not permit adjustment or does not allow normal function and development of the teeth and associated muscular structures is undesirable. It is unrealistic to expect a malocclusion that is corrected within 11/2 to 2 years, in a patient aged 12 to 15 years, will remain stable, even with long-term fixed retention. In Crozat treatment, the teeth move slowly as the dentition develops, and they gradually assume normal positions, being guided by the forces of occlusion and function. The light pressures exerted by the appliances stimulate these forces.
Special article
73
Dr. Crozat often said that teeth will move from the cradle to the grave. Retention, in this case, was merely a continuation of the active treatment in a more simplified form. Since the teeth have not been moved rapidly to new positions, their natural tendency to revert to pretreatment positions is lessened to a great degree. The appliance also has the advantage of correcting minor discrepancies by simple modification of the basic structure. REFERENCES 1. Salzmann JA. Orthodontics in daily practice. In: Parker WM. The Crozat appliance in Theory and Practice. Philadelphia: LB Lippincott, 1974. 2. Lamons FF, Holmes CW. The problem of the rotated maxillary first permanent molar. AM J ORTHOD1961;47:246-72, 266. 3. SalzmannJA. Practice oforthodontics; anchorage in orthodontics, New York: JB Lippincott, 1966:733. Reprint requests to:
Dr. Marshall Parker 111 Weisgarber Rd. Knoxville, TN 37919
Crozat appliance therapy for discrepancy problem
an
arch-length
Marshall Parker, DDS* Knoxville, Tenn.
The case involved a white male subject, aged 10 years 6 months, with a Class I molar relationship complicated by a deep overbite and impaction of all four permanent canines, which were completely blocked out of the arches. The growth rate of the arches was found to be abnormal, and there was premature loss of the deciduous teeth. Over a period of approximately 5 years, with intermittent pauses to allow growth to catch up with treatment, the Crozat removable appliance was used to help establish the arch form and correct the plane of occlusion. (AM J ORTHOP DENTOFAC ORTHOO 1991 ;99;64-73.)
CASE REPORT
Casts
The case involved a multistage treatment for malocclusion that was started in the mixed-dentition phase and completed in the permanent dentition. The patient, aged 10 years 6 months, was referred by his father, a physician specializing in plastic surgery, whose only admonition was "Don't even think about extracting any of my boy's teeth." At his initial visit, on Oct. 12, 1973, the patient had a Class I molar relationship, complicated by a deep overbite and impaction of all four permanent canines, which were completely blocked out of the arches. Three of his deciduous second molars had already erupted.
Casts revealed mesiolingual rotation of the maxillary and mandibular first molars (Fig. 2). Arch form was determined by positioning the casts so that the incisors were in a relatively desirable position. The anteroposterior relation of the molars and premolars was then noted, and a relative idea of how much rotation would be necessary to cause the upper molars to fit with the lower molars was attained. Precise arch form measurements were taken? Both of the maxillary canines, which were labially impacted, had no room to erupt. The mandibular right lateral incisor was touching and overlapping the mesial surface of the first premolar, completely obstructing the path of eruption of the lingually impacted canine. The mandibular left canine was partially trapped under the distal surface of the left lateral incisor. Both deciduous mandibular second molars and permanent first molars had already erupted.
Photographs Pretreatment frontal and lateral photographs (Fig. l) show the patient with lips closed in a relaxed position, with no asymmetry.
Radiographs *A Diplomateof the AmericanBoard of Orthodontics. 814114619
The Panoral radiograph showed severely crowded arches and a mixed-dentition development, with all permanent teeth
Fig. 1. Pretreatment facial photographs of patient at age 10 years 3 months.
64
Vohtme 99 Number 1
Special article
present. The cephalogram rcvcaled an adequate upper airway. The maxillary incisors were scvcrcly rctroinclined. The mandibular plane was fiat. The facial axis was growing at an angle that could be expected to favor horizontal arch development. Cephalometric tracings and analysis are shown in Fig. 3 and Table I.
HISTORY AND GENERAL CLINICAL PICTURE
The patient had no additional abnormal medical or dental history, and no aberrant habits were noted. Cooperation during treatment was typical for a boy of the patient's age. The probable factors affecting the patient's dental malocclusion were genetic, developmental, and functional. The
Fig. 2. Pretreatment study models of patient at age 10 years 3 months. Note arch length deficiency.
BASIC Status X-Ray
CEPHALOMETRIC
Pratraatmont
Ag~/Sex 10. 3
65
Male
10-12-73
Q
Fig. 3. Initial cephalometric tracing.
ANALYSIS
66
Parker
Am. J.
T a b l e I, O L I b a s i c c e p h a l o m e t r i c a n a l y s i s ( p r e t r e a t m e n t ) f o r p a t i e n t at a g e 10.3 y e a r s
Variable
Norm
tI
Patient
Difference - 1.78 ° 5.23 ° 5.48 ° -4.60 ° - 5.92 ° 1.32 ° - 4.59 ° - 10.60 ° - 2 . 3 5 mm - 8.98 ° - 2 . 9 6 mm < ! . 1 9 mm 19.39 o 2.25 ° 4.83 ° - 2 . 9 5 mm Within range Within range 1 . 3 0 mm - 1.59 o Within range Within range Within range 6.57 ° - 6.44 ° 1.02 ° - 8.92 °
SN to horizon FH to horizon SN to FH SNA SNB ANB SND
7° 0° 5° 82 ° 80 ° 2° 76 °
5.22 ° 5.23 ° 10.48 ° 77.400 74.08 ° 3.32 ° 71.41 °
I / to N A
22"
11.40 °
1 / to N A
/ I to NB /1 to NB /1 to APO 11 to fi ANS-PNS to SN Occ to SN GoGn to SN GoGn GoCo GoGn minus GoCo GoGn to GoCo /M lip to E line M / l i p to E line Facial axis IMPA FMA FMIA Z angle
4 mm
25 ° 4 mm - 1 to 3 mm I31 ° 8° 14° 32 ° 70-86 mm 49-65 mm 21 mm 123 ° - 4 to 0 mm - 3 . 7 to 0.28 mm 87-93 ° 87 ° 25 ° 68 ° 78 °
Rotation center is 15 mm from incisal tip. IMPA is adjusted to a boundary limit of 95 °. Estimated crowding is
1 . 6 5 mm 16.02 ° 1.04 mm - 2 . 1 9 mm 150.39 ° 10.25 ° 18.83 ° 29.05 ° 73.10 mm 50.80 mm 22.30 mm 121.41" - 1.72 mm - 1.22 mm 91.77 ° 93.57 ° 18.56 ° 69.02 ° 69.08 °
/1 MD/FL1 × 2 /2 MD/FL2 x 2 Sagittal diagnosis: Maxillary incisor retroinclined
I
Adjusted value
75.62 ° 72.30 ° 69.63 °
12.03 °
15.33 ° 72.25 ° 72.31 °
10.76 mm
Resolution of tooth to arch size descrepancy with flattened curve of Spee: IMPA (Referenced to Down's occlusal plane) IMPA (Referenced to new molar--incisor plane)
111213 to 112131
Orthod. Dentofac. Orthop. January 1991
118.20 ° 118.07 °
2.490 mm excess width 1.665 mm excess width .7679 mm excess width
Adapted from a table by Orthodontic Logic, Inc., ~ 1987.
patient's facial characteristics were very similar to those o f his father. Relative growth rate o f the arches in the dentofacial region appeared to be abnormal, and a local functional c o m p o n e n t affecting this case was premature loss o f deciduous teeth.
TREATMENT PLAN The initial treatment plan was first to attempt the necessary arch change by correcting the axial positions o f the permanent first m o l a r s ? This approach was based on the patient's chronological and developmental age, as well as on his dental age. The first molars erupt first, and therefore must be corrected first. It was a s s u m e d that significant space could
be gained by the correction o f abnormally rotated molars. ~ T h e Crozat removable appliance was used for this purpose. As the arch f o r m developed, deciduous teeth exfoliated, and g r o w t h continued d o w n w a r d and forward, the extraction o f p e r m a n e n t teeth b e c a m e unnecessary because the teeth aligned and leveled themselves. The correction o f the plane o f occlusion and the creation o f normal intermaxillary dental arch relation occurred coincidentally with the establishment o f the arch form, aided by horizontal growth. Simple reciprocal intramaxillary anchorage, 2 obtained by a.ctivating the appliance, prevented mesial migration of the first permanent molars as the patient's face g r e w d o w n w a r d and forward. Adjustment o f the appliance exerted force out-
Volume 99 Number I
Special article
Fig. 4. Posttreatment facial photographs of patient at age 16 years 5 months.
Fig. 5. Posttreatment study models of patient at age 16 years 5 months.
67
68 Parker
Am. J. Orthod.Dentofac.Orthop. January 1991
ANALYSIS
CEPHALOMETRIC
BASIC
Stotus Post-treotm~nt A g ~ / S e × 16. 5 N o l ~
X-Roy
7B. 3 4 7 7 . 48
12-2B-Tg
15.59 64. g I
_J "V Fig. 6. Posttreatment cephalometric tracing.
Table II. OLI basic cephalometric analysis (posttreatment) of patient at age 16.5 years
Variable
[
Norm
]
Patient
[
Difference
S N to h o r i z o n
7°
4.67 °
F H to h o r i z o n
0°
4.37 °
4.37 °
SN to FH
5°
9.07 °
4.07 °
I
Adjustedvalue
- 2.33 °
SNA
82 °
78.34 °
- 3.66 °
76.01"
SNB
80 °
77.48 °
- 2.52 °
75.15 °
ANB
2o
0.86 °
- 1.14 °
76*
76.06 °
0.06 °
22"
24.94 °
2.94 °
SND I/to
NA
1/to
NA
4 mm
/ 1 to N B / 1 to N B / 1 to A P O
5.88 mm
25 ° -
i/toll
22.14 °
1.88 m m - 2.86 °
4 mm
3.28 mm
-0.72 °
l to 3 m m
1.65 m m
Within range
131 °
133.21 °
8°
8.56 °
0.56 °
14 °
11.95 °
- 2.05 °
A N S - P N S to S N O c c to S N G o G n to S N
73.73 °
32 °
2.21 °
24.66 °
10.89 °
- 7.34 °
GoGn
70-86 mm
81.01 m m
Within range
GoCo
49-65 mm
62.49 mm
Withih range
21 m m
18.51 m m
GoGn minus GoCo G o G n to G o C o / M lip to E line M/lip
to E line
123 ° -4 -4.9
115.89 °
to 0 m m to - . 9 8
mm
-2.49
mm
- 7.11 °
-2.99
mm
Within range
-3.33
mm
Within range
Facial axis
87-93 °
IMPA
87"
100.65"
13.65 °
FMA FMIA
25 ° 68 °
15.59 ° 64.91 o
-9.41 ° - 3.09 °
67.29 °
Z angle
78 °
75.97 °
- 2.03 °
78.34 °
95.09"
>2.09 13.22 °
Volume 99 Number 1
Special article
Croniol 07-01-63
SupQ~position
Bas@
H
' ""'- ....
SN AT S Ter'm I r'~e 4
Ncas i otq
354.77
^~ga.
_ ! ~..s. L2z_La-._Lg__pe_._t_L
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ttt
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l
°_.
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ts
Fig. 7. Superimposed pre- and posttreatment cephalometric tracings. Note downward and forward growth pattern.
Table III. OLI basic cephalometric analysis (final posttreatment) at age 22.1 years
r ,b,e
I
No..,
I
l
O r.nce
I
Adjusted value
S N to h o r i z o n
7°
9.85 °
2.85 °
FH to horizon
0°
0.87 °
0.87 °
S N to F H
5°
9.04 °
4.04*
SNA
82 °
78.90 °
- 3.10 °
81.74 °
SNB
80 °
78.44 °
- 1.56 °
81.28 °
ANB
2°
0.46 °
- 1.54 °
SND
76 °
76.86 °
0.86 °
1/to NA
220
25.61 °
3.61 °
1/to NA
4 mm
/ 1 to NB
25 °
/ 1 to N B / 1 to A P O
6.41 m m 22.02 °
4 mm
1 / to / 1 A N S - P N S to S N O c c to S N G o G n to S N
2.41 m m - 2.98 °
2.92 mm
- 1 to 3 m m
1.22 m m
- 1.08 m m Within range
131 °
133.06 °
2.06 °
8°
8.43 °
0.430
14 °
11.25 °
-2.75 °
32 °
24.02 °
70-86 mm
83.68 mm
Within range
GoCo
Within range
49-65 mm
64.32 mm
GoGn minus GoCo
21 m m
19.36 m m
G o G n to G o C o
123"
M/lip
to E line
Facial a x i s
-4 -5.8
115.89 °
to 0 m m to - 1 . 8 87-93 °
mm
- 1.64 m m - 7.11 °
-3.87
mm
Within range
-3.99
mm
W i t h i n .range
96.28 °
558 °
-7.98 °
GoGn
/ M l i p to E line
79.70 °
>3.28
1MPA
87 °
100.21 °
13.21 °
FMA
25 °
14,98 °
- 10.02 °
FMIA
68 °
65.95 °
- 2.05 °
13.85"
Z angle
78 °
76.54 °
- 1.46 °
67.08 ° 77.67 °
69
70
Parker
A m . J. Orthod. Dentofac. Orth January 1
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Voh,me 99
Special article
Number 1
71
Fig. 9. Final posttreatment facial and intraoral photographs of patient at age 22 years 1 month.
ward or laterally, as well as distally, to eliminate the anterior constriction of and possible mandibular entrapment from the retroinclined maxillary incisors. When the appliance was adjusted, there was a tendency for it to extricate itself from the teeth. This phenomenon aided the vertical growth of the posterior teeth. The posterior movement was augmented or increased by the addition of lingual springs at the gingival margins of the upper and lower retroinclined incisors. TREATMENT PROGRESS
The upper and lower appliances were placed on separate occasions, 1 week apart, so the patient could become accustomed to one appliance before the second one was placed. After I month when the patient had become fully accustomed to the appliances, rotational adjustments were made in both appliances to rotate the molars. Six weeks later, lapping sweep springs were soldered to the ends of the lingual arms of the lower appliance and contoured so that they touched the cingula of all the incisors and ended at the canines. At this same
appointment, another rotational adjustment was made in the maxillary appliance. During the next 8 months, only one rotational adjustment was made in each appliance. The patient continued to wear his appliances, however. This interval was a planned rest period, in which the patient had to grow to catch up with the adjustments. During this time the remaining deciduous teeth were lost. Throughout treatment, the patient was seen at intervals of 5 or 6 weeks. One year after treatment had been initiated, elastic hooks and Class I1 5/16-inch, 3.5-ounce latex elastics were added. Much of the malocclusion had already begun to correct itself. The molars'were in neutrocclusion, and space was beginning to develop for the canines. During the next 2 years, two additional rotational adjustments were made. During sleeping hours, the patient wore Class II elastics, and again, there were planned rest periods to allow growth to catch up with the adjustment. After 3V2 years, there was enough room for the maxillary canines to
72
Parker
Am. J. Orthod. Dentofac. Orthop. January 1 9 9 1
OPomiol
Bos@
SupQmpos
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07-01-6:9 l ~ d * N I m ~ O=~a
SN AT S A~¢ho~ 6 Terminus 4 ^~.
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•'J'l :
~
;
~-J/V ,
Fig. 10. Superimposed pre-, post-, and final-observation cephalometric tracings.
erupt. A finger spring was soldered to the buccal arm above the elastic hook and bent to engage the mesial surface of the upper canines. The patient continued to wear elastics full time. The mandibular canines erupted without additional help. When all the canines were in normal relation, the patient was instructed to wear his elastics at night only but to wear the appliances all the time. By Sept. 5, 1978, he was asked to wear the appliances at night only. He was seen at 3-month intervals until Dec. 28, 1979, when posttreatment records were taken. Retention was not a problem; it occurred coincidentally with the progression of treatment. Time and function helped to produce the desired result.
RESULTS Photographs Both lateral and frontal photographs showed a pleasing face in which the teeth were in harmony with the musculature when the lips were in repose (Fig. 4).
Casts Posttreatment casts showed all the teeth present and in a Class I relationship. The dental midline matched that of the face, and there was good interdigitation (Fig. 5).
Radiographs No root resorption was evident on the panoramic radiographs. Axial inclination was normal. The posttreatment
cephalometric analysis showed that the maxillary incisors were no longer retroinclined (Fig. 6 Table II). No auxiliary attachments had ever been worn on the labial surfaces of the maxillary incisors. The cranial base superposition (Fig. 7) revealed that as the face grew downward and forward, the molars were rotated and kept from erupting quite as fast as the rest of the teeth (Fig. 8, A and B). Four impacted third molars were extracted on August 13, 1981. The maxillary and mandibular occlusograms revealed that first and second molars were not driven distally to impact the third molars (Fig. 8, A and B). The mandibular occlusogram showed that the arch had not expanded in the canine area. In fact, the permanent canines were lingual to the position of the premolars that had formerly occupied the space. Total treatment time, including pauses for growth and retention, was approximately 5 years. The procedure was to treat and pause, treat and pause, treat and pause, always allowing growth to catch up with treatment. An observation of particular interest is that a greater amount of tooth movement took place during the planned rest intervals than during continuous active treatment. When the molars are rotated distobucally, they must assume a position in a wider portion of the arch as growth takes place in a downward and forward direction. In this case, all four first molars were originally ovcrrotated, causing the central groove to be awry. This situation was corrected during treatment by the addition of auxiliary wires attached to the body wire and resting on the second molars.
Volume 99 Number 1
FINAL EVALUATION
The final posttreatment records were taken 6 years later, on Aug. 13, 1985 (Figs. 9, 10, and Table III). Retention was not a problem, since time and function helped to produce a pleasing and harmonious result. COMMENTARY
The Crozat philosophy is based on the premise that occlusion is not static but is a dynamic condition throughout life. Since the greatest amount of change occurs during the first 25 years of life, a fixed or removable retainer that does not permit adjustment or does not allow normal function and development of the teeth and associated muscular structures is undesirable. It is unrealistic to expect a malocclusion that is corrected within 11/2 to 2 years, in a patient aged 12 to 15 years, will remain stable, even with long-term fixed retention. In Crozat treatment, the teeth move slowly as the dentition develops, and they gradually assume normal positions, being guided by the forces of occlusion and function. The light pressures exerted by the appliances stimulate these forces.
Special article
73
Dr. Crozat often said that teeth will move from the cradle to the grave. Retention, in this case, was merely a continuation of the active treatment in a more simplified form. Since the teeth have not been moved rapidly to new positions, their natural tendency to revert to pretreatment positions is lessened to a great degree. The appliance also has the advantage of correcting minor discrepancies by simple modification of the basic structure. REFERENCES 1. Salzmann JA. Orthodontics in daily practice. In: Parker WM. The Crozat appliance in Theory and Practice. Philadelphia: LB Lippincott, 1974. 2. Lamons FF, Holmes CW. The problem of the rotated maxillary first permanent molar. AM J ORTHOD1961;47:246-72, 266. 3. SalzmannJA. Practice oforthodontics; anchorage in orthodontics, New York: JB Lippincott, 1966:733. Reprint requests to:
Dr. Marshall Parker 111 Weisgarber Rd. Knoxville, TN 37919
