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Class I neutroclusion
CLASS
I NEUTROCLUSION REPORT
ASHLEY
OF
A
CASE
E. HOWES, D.D.S., NEW ROCHELLE,
N. Y.
T
HIS case report is presented not because there is anything unusual in the treatment, but because an analysis of the tooth movements may be of passible interest. The patient was a boy 11 years old. As can be seen from the models (Fig. 1)) this was a Class I neutroclusion case with crowded maxillary and mandibular incisors and with the four cuspids partially blocked out of the arch. The maxillary cuspids had not yet erupted, but it was obvious that there was only about half enough space for them. There was a slight labial inclination of the maxillary central incisors. As distinguished from the remote or underlying causes which are unknown, the proximate cause, that is, the immediate reason for the existence of this malocclusion, I believe to be a disharmony between 6he total amount of the tooth material and the size and form of the basal arches which support the tooth material. The basal arches were slightly deficient both laterally and anteroposteriorly, although the lateral deficiency was slight. The boy had 98 mm. of tooth material from the maxillary first molar to the maxillary first molar, which called for an arch about 43 mm. wide across the buccal cusps of the first premolars. The maxillary arch was 35 mm. wide in this region in the original condition, but if it had been possible to move all of the buccal teeth distally to where the basal arch was wider, then there would have been almost sufficient basal arch width to support a dental arch of normal width. The anteroposterior deficiency will be demonstrated later. Following the extraction of the four first premolars, the mechanical therapy employed in the treatment of this patient was as follows: The first molars and the four maxillary incisors were banded. Removable lingual arches and twin wire labial arches were placed. The mandibular lateral incisors were ligated to the twin wire arch. The mandibular cuspids were moved distally by the wedging action of the lateral incisors as t,hese teeth were moved forward. Slight intermaxillary elastic force was used to retract the maxillary central incisors. After the maxillary cuspids erupted, they were banded and moved distally by means of coil springs on the twin wire section of the arch between the lateral incisor bands and the cuspid bands. Active treatment extended over a period of about twenty months. The mandibular twin wire arch was in place only a short portion of this time. Observe the positions of the mandibular cuspids, which still slightly overlap the lateral incisors. The reason for this will be pointed out later. The third Presented
before
the
Northeastern
Society
of
1949.
587
Orthndontists.
New
York,
N.
Y.,
Nov.
29.
588
ASHLEY
E.
HOWFS >1
molars are erupting in good positions. The boy was 18 years old when the second models were made. The orthographic projections of the case before and after treatment arc shown in Fig. 2 (before treatment on the left, after treatment on the right).
Fig.
l.--Models
before
and
srvcrnl
years
after
treatment.
Note the normal relationship) of Ihc antrrioi+ t&h to the basal after treat,ment and how the huwal teeth fall within I he basal arch The mandibular basal arch outline before and after hreatment.. forward of the maxillary basal arch outline in both the original lrlap of the case after treatment, which is a normal anteroposterior
arch outlines outlines both lies slightly map and the relationship
CLASS
I
589
NEUTROCLUSION
the maxillary basal arch outline and of the basal arches. By superimposing median raphe of the patient before treatment upon the same lines of the patient after treatment, we are able to demonstrate the tooth movements which actually occurred. The composite maxillary and mandibular maps showing the tooth movements are seen in Fig. 3. The maxillary central incisors have been retracted, t,hc lateral incisors have been rotated and moved distally, the cuspids have been been moved distally, and the residue spaces created by the extractions of the first prtmolars have been closed by the mesial movements of the teeth distal lo ttw spaces.
Fig. P.-Maps the left and after dibular teeth and
of maxillary and man(libulxr teeth and basal arches. Maxillary teeth and basal arch treatment on the right. basal arch outlines ~~lottml.
Fig. :3.--Composite before treatment and n~ap on the right.
maps of dotted lines
ca.w after
showing treatment.
tooth
movements Mandibular
Before outlines
accomglished. may on the
tre?tment soh~l.
left:
on Man-
Solid lines maxillars
The mandibular central incisors remained about where they were, the lateral incisors moved forward, the cuspids moved distally, and the residue spaces were closed by t,he mesial movements of the teeth distal to the spaces. There was fully as much forward movement of the post,erior teeth as t’here was dist,al movement of the cuspids. The objcrt of this case report is IO present not. only an analysis of the tooth movements actually accomplished following the extraction of the four premolars, lmt also to demonstrate the tooth movements which would have been necessary if no teeth had been extracted. A method of ascertaining these movements through the use of models alone will be described.
590
ASHLEY
Duplicate models were made, and The original models should record as and care must be exercised in making them perpendicular to the base, and anatomical portions of the models.
Fig.
4.-Wax
Fig.
B.-Maxillary
E.
HOWES
the teeth were cut off as shown in Fig. 4. much of the supporting bone as possible, the saw cut.s between the teeth, keeping being sure to run them high ~111 int,o the
setup. Black lines indicate amount maxillary have to be moved distally if full complement
and mandibular basal arches into them, showing mesiodistal
of original positions
and mandibular Arst of teeth is maintained.
molars
would
models with of various
running
down
saw cuts teeth.
When the teeth are set up, the anterior teeth should be placed in proper relationship to their supporting bone, and the arch should be made no wider than the basal arches as shown in Fig. 5. When the setup has been made in this manner, it is possible to see how much expansion and how much distal movement of the buccal teeth will be required. The distal movement is indicated by observing the relationship of the teeth in their new posit,ions to the vertical cuts in the models, which show where the same t,eeth had been originally. On the carved portion of these models, I have drawn lines above and below the cuts
CLASS
Fig.
G.-Composite
Fig.
7.-Wax
setup
maps
of
of
posterior leaving
Fig.
I NEUTROCLUSION
original models maintain full
and setup, complement
591
showing of teeth.
teeth made on models of relationship of anterior teeth
8.--Photograph
of boy
several
years
tooth
movements
case several undisturbed.
after
treatment.
Scars
necessary
after
treatment.
to
which were mesial to the first molars in thcil- original positions and ot,her lines m&al to the rllolars in their IICW positious. The rnilxillary molars woulC1 have t0 be moved nearly 5 mm. tlist;rll~-! while the ~l~antlil)l~l;~r molars would also have to be moved distally about 3.5 mm. The ;rnt.erior teeth had to bc spaced in Order to go around the mandil)ular iricisor~s. Thc~ spn~s indicate ii dishannong between the maxillary and mandibular antchrior toot II material, the mandibelar incisors being too large for the maxillary incisors. These models were surveyed in order to point, out graphic2lly all of thti toot11 movements which would be necessary if no teeth wcrc extracted. Composite niaps of this setup ( I+‘& 6) related to the original map indicate the SillllC mo~cmenfs in a little more dctail. Ml of the buccal teeth. both maxillary and mandibular (practically lhc entire denture) woaltl ha\-c to be moved distally several millimet~ers. The maxillary teeth would require the gWilt(>r movc~nlent, because iii ihc original condition they were forward of their llO~~U;tl relatiolls with their mandibular antagonists. IGg. 7 presents another setup, preserving a full complement Of teeth, but differing from the previous one in that it has been made on the aftertreatment models of the case, leaving t tic six anterior teeth ,just as they were in the finished case. Several observations (‘iIll be made : 1. The arch is too long and narrow because of basal arch deficiency. 2. The third molars would have had to be removed, even if the movements were possible, as thep would have been impacted. These teeth extend beyond t>he tuberosities, the limits of whicdh arc indicated by the posterior part of the model bases, which were planed just in back of the tuberosities. 3. The crowding of the mandibular inc+sors in the finished case was a result of disharmony of tooth material. The tip of the left maxillary lateral incisor was accidentally broken off? but not repaired. because it allows a clC.?itrview 01’ tlicl good relationship of the maxillary- and mandibular (auspids. Certainly- the inc4sors should not, be moved forward t,o eliminate this crowding oE the mantlibular cuspids, nor can the mandibular cuspids be moved distally without moving the maxillary cuspids distally also in order to preserve Uieir proper relationship. This would mean that if the crowding of the mandibular cuspids is to be eliminated, all Of the maxillary and mandibular trct h distal to t,he lateral incisors would liavt~ to br mo\-et1 distally, which woultl ol)en spaces l)&veen the nmsillary anterior teeth. These spaces WVI’C prcscnt in the previous setup shown in Fig. 1, because in that setup the mandibular incisors and cuspids were aligned with unbroken contacts, and t.he rnasillary incisors had to be spaced because of the disharmony in the maxillary and mandibular tooth material. Such spaces coultl l>roh>ll)ly not be maintained even if t,liey were desirable. The photograph Of the boy at 18 (E’ig. 8) presents no “dished in” appearance of t,he face, not only because the teeth are in normal relationship with theil supporting boric, a condition over which I had some control, hut, also because the basal arches bear a satisfactory relat,ionship with the facial plane, a condition over which I had no control.
I NEUTROCLUSION REPORT
ASHLEY
OF
A
CASE
E. HOWES, D.D.S., NEW ROCHELLE,
N. Y.
T
HIS case report is presented not because there is anything unusual in the treatment, but because an analysis of the tooth movements may be of passible interest. The patient was a boy 11 years old. As can be seen from the models (Fig. 1)) this was a Class I neutroclusion case with crowded maxillary and mandibular incisors and with the four cuspids partially blocked out of the arch. The maxillary cuspids had not yet erupted, but it was obvious that there was only about half enough space for them. There was a slight labial inclination of the maxillary central incisors. As distinguished from the remote or underlying causes which are unknown, the proximate cause, that is, the immediate reason for the existence of this malocclusion, I believe to be a disharmony between 6he total amount of the tooth material and the size and form of the basal arches which support the tooth material. The basal arches were slightly deficient both laterally and anteroposteriorly, although the lateral deficiency was slight. The boy had 98 mm. of tooth material from the maxillary first molar to the maxillary first molar, which called for an arch about 43 mm. wide across the buccal cusps of the first premolars. The maxillary arch was 35 mm. wide in this region in the original condition, but if it had been possible to move all of the buccal teeth distally to where the basal arch was wider, then there would have been almost sufficient basal arch width to support a dental arch of normal width. The anteroposterior deficiency will be demonstrated later. Following the extraction of the four first premolars, the mechanical therapy employed in the treatment of this patient was as follows: The first molars and the four maxillary incisors were banded. Removable lingual arches and twin wire labial arches were placed. The mandibular lateral incisors were ligated to the twin wire arch. The mandibular cuspids were moved distally by the wedging action of the lateral incisors as t,hese teeth were moved forward. Slight intermaxillary elastic force was used to retract the maxillary central incisors. After the maxillary cuspids erupted, they were banded and moved distally by means of coil springs on the twin wire section of the arch between the lateral incisor bands and the cuspid bands. Active treatment extended over a period of about twenty months. The mandibular twin wire arch was in place only a short portion of this time. Observe the positions of the mandibular cuspids, which still slightly overlap the lateral incisors. The reason for this will be pointed out later. The third Presented
before
the
Northeastern
Society
of
1949.
587
Orthndontists.
New
York,
N.
Y.,
Nov.
29.
588
ASHLEY
E.
HOWFS >1
molars are erupting in good positions. The boy was 18 years old when the second models were made. The orthographic projections of the case before and after treatment arc shown in Fig. 2 (before treatment on the left, after treatment on the right).
Fig.
l.--Models
before
and
srvcrnl
years
after
treatment.
Note the normal relationship) of Ihc antrrioi+ t&h to the basal after treat,ment and how the huwal teeth fall within I he basal arch The mandibular basal arch outline before and after hreatment.. forward of the maxillary basal arch outline in both the original lrlap of the case after treatment, which is a normal anteroposterior
arch outlines outlines both lies slightly map and the relationship
CLASS
I
589
NEUTROCLUSION
the maxillary basal arch outline and of the basal arches. By superimposing median raphe of the patient before treatment upon the same lines of the patient after treatment, we are able to demonstrate the tooth movements which actually occurred. The composite maxillary and mandibular maps showing the tooth movements are seen in Fig. 3. The maxillary central incisors have been retracted, t,hc lateral incisors have been rotated and moved distally, the cuspids have been been moved distally, and the residue spaces created by the extractions of the first prtmolars have been closed by the mesial movements of the teeth distal lo ttw spaces.
Fig. P.-Maps the left and after dibular teeth and
of maxillary and man(libulxr teeth and basal arches. Maxillary teeth and basal arch treatment on the right. basal arch outlines ~~lottml.
Fig. :3.--Composite before treatment and n~ap on the right.
maps of dotted lines
ca.w after
showing treatment.
tooth
movements Mandibular
Before outlines
accomglished. may on the
tre?tment soh~l.
left:
on Man-
Solid lines maxillars
The mandibular central incisors remained about where they were, the lateral incisors moved forward, the cuspids moved distally, and the residue spaces were closed by t,he mesial movements of the teeth distal to the spaces. There was fully as much forward movement of the post,erior teeth as t’here was dist,al movement of the cuspids. The objcrt of this case report is IO present not. only an analysis of the tooth movements actually accomplished following the extraction of the four premolars, lmt also to demonstrate the tooth movements which would have been necessary if no teeth had been extracted. A method of ascertaining these movements through the use of models alone will be described.
590
ASHLEY
Duplicate models were made, and The original models should record as and care must be exercised in making them perpendicular to the base, and anatomical portions of the models.
Fig.
4.-Wax
Fig.
B.-Maxillary
E.
HOWES
the teeth were cut off as shown in Fig. 4. much of the supporting bone as possible, the saw cut.s between the teeth, keeping being sure to run them high ~111 int,o the
setup. Black lines indicate amount maxillary have to be moved distally if full complement
and mandibular basal arches into them, showing mesiodistal
of original positions
and mandibular Arst of teeth is maintained.
molars
would
models with of various
running
down
saw cuts teeth.
When the teeth are set up, the anterior teeth should be placed in proper relationship to their supporting bone, and the arch should be made no wider than the basal arches as shown in Fig. 5. When the setup has been made in this manner, it is possible to see how much expansion and how much distal movement of the buccal teeth will be required. The distal movement is indicated by observing the relationship of the teeth in their new posit,ions to the vertical cuts in the models, which show where the same t,eeth had been originally. On the carved portion of these models, I have drawn lines above and below the cuts
CLASS
Fig.
G.-Composite
Fig.
7.-Wax
setup
maps
of
of
posterior leaving
Fig.
I NEUTROCLUSION
original models maintain full
and setup, complement
591
showing of teeth.
teeth made on models of relationship of anterior teeth
8.--Photograph
of boy
several
years
tooth
movements
case several undisturbed.
after
treatment.
Scars
necessary
after
treatment.
to
which were mesial to the first molars in thcil- original positions and ot,her lines m&al to the rllolars in their IICW positious. The rnilxillary molars woulC1 have t0 be moved nearly 5 mm. tlist;rll~-! while the ~l~antlil)l~l;~r molars would also have to be moved distally about 3.5 mm. The ;rnt.erior teeth had to bc spaced in Order to go around the mandil)ular iricisor~s. Thc~ spn~s indicate ii dishannong between the maxillary and mandibular antchrior toot II material, the mandibelar incisors being too large for the maxillary incisors. These models were surveyed in order to point, out graphic2lly all of thti toot11 movements which would be necessary if no teeth wcrc extracted. Composite niaps of this setup ( I+‘& 6) related to the original map indicate the SillllC mo~cmenfs in a little more dctail. Ml of the buccal teeth. both maxillary and mandibular (practically lhc entire denture) woaltl ha\-c to be moved distally several millimet~ers. The maxillary teeth would require the gWilt(>r movc~nlent, because iii ihc original condition they were forward of their llO~~U;tl relatiolls with their mandibular antagonists. IGg. 7 presents another setup, preserving a full complement Of teeth, but differing from the previous one in that it has been made on the aftertreatment models of the case, leaving t tic six anterior teeth ,just as they were in the finished case. Several observations (‘iIll be made : 1. The arch is too long and narrow because of basal arch deficiency. 2. The third molars would have had to be removed, even if the movements were possible, as thep would have been impacted. These teeth extend beyond t>he tuberosities, the limits of whicdh arc indicated by the posterior part of the model bases, which were planed just in back of the tuberosities. 3. The crowding of the mandibular inc+sors in the finished case was a result of disharmony of tooth material. The tip of the left maxillary lateral incisor was accidentally broken off? but not repaired. because it allows a clC.?itrview 01’ tlicl good relationship of the maxillary- and mandibular (auspids. Certainly- the inc4sors should not, be moved forward t,o eliminate this crowding oE the mantlibular cuspids, nor can the mandibular cuspids be moved distally without moving the maxillary cuspids distally also in order to preserve Uieir proper relationship. This would mean that if the crowding of the mandibular cuspids is to be eliminated, all Of the maxillary and mandibular trct h distal to t,he lateral incisors would liavt~ to br mo\-et1 distally, which woultl ol)en spaces l)&veen the nmsillary anterior teeth. These spaces WVI’C prcscnt in the previous setup shown in Fig. 1, because in that setup the mandibular incisors and cuspids were aligned with unbroken contacts, and t.he rnasillary incisors had to be spaced because of the disharmony in the maxillary and mandibular tooth material. Such spaces coultl l>roh>ll)ly not be maintained even if t,liey were desirable. The photograph Of the boy at 18 (E’ig. 8) presents no “dished in” appearance of t,he face, not only because the teeth are in normal relationship with theil supporting boric, a condition over which I had some control, hut, also because the basal arches bear a satisfactory relat,ionship with the facial plane, a condition over which I had no control.