Case report
Published on 03/12/96
| Patient | |
|---|---|
| Age: | 11.8 |
| Diagnosis | Angle cl.II div.2 |
| ANB | 7 |
| OJ | 2 |
| OB | 10 |
The patient is an eleven-year old boy, in good general
health.
Due to a fear of dentists and dental treatment, he had seven deciduous teeth extracted
under general anaesthesia at the age of seven.
His dental history is non-contributory and free of any events that could have affected the
development of his permanent teeth.
There are no bad habits present.
According to his mother, his cousins have a similar malocclusion.
He is of average build and average to small, when compared
to boys in his age group.
His face is round, with no asymmetry. The profile is convex, the chin is average and the
nose seems to be small.
The face height appears normal and so does the jaw inclination. The jaw and the lip
muscles are somewhat hypertonic. Both upper and lower lips seem to be thick but normal in
length.
When swallowing, the teeth are in contact with no tongue thrust and no mentalis
contraction. He is a nose breather.
The path of closure from rest to habitual occlusion is normal, with no premature tooth
guidance or mandibular displacement.
The oral hygiene appears adequate, and the caries activity is low.
The soft tissue shows normal texture and colour of the gingiva and mucosa.
Labial frenum, tongue size and lingual frenum are also normal.
The intraoral radiographs show mixed dentition
with restorations on 54,55 and 65.
The tooth bud for 25 is positioned horizontally.
It is difficult to find any signs indicating that his third molars are developing and
judging by his age, it is very unlikely that he will develop them.
The actual molar relationship is a bilateral Class I.
Since the lower first molars are mesialized about 3-4 mm, the true molar relationship is
Class II.
The canines on both sides are in a Class II relationship.
The overjet is 2 mm. With regards to the vertical relations, the permanent mandibular and
maxillary incisors are over-erupted.
The overbite is 10 mm and the lower incisors are impinging the palatal gingiva.
The Curve of Spee is moderate and the lower incisors are retroclined.
The dental midlines are coincident with the facial midline.
12 is mesially tipped and 22 is distally tipped . 55, 14, 24 and 65 are in cross bite.
The following teeth are present:
| 6e4c21 | 12c4d6 |
| 6 4321 | 1234 6 |
The alveolar process breadth is normal.
The upper arch form is U-shaped and the lower is more or less parabolic.
The mandibular inter-canine distance is 30 mm and the intermolar distance is 52 mm.
12, 22 and 41 are rotated.
Space analysis reveals 4.5 mm of upper crowding and 12.5 mm
of lower crowding.
The value of the overall ratio is within the normal range,
but the value of the anterior ratio shows 2 mm difference with the correct width of the
lower anterior teeth.
|
 The SNA angle of 79 shows that the maxilla is in an orthognatic position, but 72° for the SNB puts the mandible in a retrognathic position. The value of ANB angle indicates distal basal sagittal relation. SNPg, with 72°, is in accordance with the value of SNB. Both the mandibular and the nasal plane are posteriorly inclined (37°) and the inclination of the maxilla is 14.5 degrees. However, the intermaxillary angle is within normal limits at 22.5°. |
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| The mandibular angle (127°) reveals a
posterior growth rotation pattern. The face ratio gives a contradictory value, suggesting an anterior growth rotation at 96.5°. There is extreme retrusion of the upper incisors wich are distal to the NA line 5 mm. The lower incisors are also retroclined, but still mesial to the NB line 2.5 mm. The value of the interincisal angle is 135°. The Pg point is lying on the NB line. Despite the retrusion of the incisors, the lips are in a mesial position to the EL: UL-EL=-5.5 mm and LL-EL=-3.5 mm. The H-angle is equals 24°. |
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He is in MP3 stage and the growth appears to have a
posterior pattern.
This is unfavorable for the treatment planning, as he has a distal basal sagittal
relation.
It is difficult to make a definite prognosis for the value
of ANB after treatment.
Despite the posterior growth rotation, we might expect a reduction of approximately 3°:
from 7° to 4°.
That will be due to the positive torque in upper arch, and maybe to some mesial movement
of the mandible after its "unlocking" from the distal position.
Pg will, most probably be unchanged: approximately 0 mm.
These two anticipated values bring us to the following position of the incisors:
Following the Steiner analysis it can be seen that there is a 5 mm protrusion of the upper
incisors and an unchanged position of the lower ones.
In order to reach interincisal contact, protrusion of the lower incisors is also
necessary.
In this case the results obtained from the Steiner Analysis are not very meaningful for
our treatment planning.
The prognosis for the N-angle and H-angle are: 6.23 mm and 11.9° respectively.
The anticipated value for the N-angle shows the need for the protrusion of the lower
incisors.
As the mother informed that there are cousins who have the
same malocclusion, then it is safe to say that the etiology is likely hereditary.
The treatment need is prophylactic, functional, and
esthetic.
The very deep bite and incisors that impinge palatal gingiva can cause periodontal
problems and impair the normal functions.
By resolving these problems, the patient will also benefit esthetically.
There is 12.5 mm of crowding in the lower arch.
To correct the curve of Spee we need 2 mm. Therefore, 14.5 mm of space is required.
Even with molar distalization, incisor protrusion and interproximal reduction, it will be
difficult to provide enough space for the second premolars.
There is 4.5 mm of crowding in the upper arch. Protrusion of the incisors will provide the
space needed. Therefore extractions are not necessary in order to gain more space.
However, there is great transverse discrepancy between the two jaws (crossbite) and
extracting in the lower arch will necessarily be followed by extractions in the maxilla.
In this stage of treatment the extractions will be postponed, but it is very likely that
this is going to be a four premolar extraction case.
As to the teeth that are going to be extracted, due to the deep bite, it is better to
extract as mesial as possible, so the choice will be: 14, 24, 34 and 44.
The only potential problem is the position of the toothbud for 25 which is horizontally
placed and if the prognosis for its eruption is poor, then the extraction choice must be
reevaluated.
Tooth movement
In the initial stages of treatment the upper incisors are
proclined, thus releasing the mandible to grow freely.
Upper and lower incisors are intruded, while the posterior segments are extruded in order
to decrease the overbite.
Anchorage requirements are not critical at this stage.
Reciprocal intraoral anchorage will be used in the expansion phase and later if there are
any extractions, then intraoral class II elastics will be used.
It will be necessary to reevaluate the case after the initial treatment and decide about
extractions.
| OCT.90 | Dental and medical history, clinical examination, intra-
and extra-oral photographs, impressions for study models, and radiographs (cephalogram, hand-wrist, panorex) were taken. |
| DEC.90 | Bonded all permanent teeth .016 |
| FEB.91 | Bonded lower arch. |
| MAR. 91 | Levelled upper arch. .018 Australian wire |
| MAY. 91 | .018 Australian wire with loops for frontal expansion and stops for the molars. .016 Australian wire |
| AUG. 91 | Referred for extraction of 34 and 44.Utility arch inserted in the LA. |
| OCT.91 | 25 has an oblique eruption path and the crown is most probably buccally and the root palatally. |
| NOV.91 | Referred for extraction of 55 and 65 and waiting for eruption of 15 and 25. .018 Australian with stop for the molars. |
| MAR.92 | Bonded 25,45 and included in the arch with nitinol .016x.022 |
| MAY.92 | Resorption on the mesial part of the root of 24. Referred for extraction of 14, 24. |
| OCT.92 | Bonded upper canines. |
| DEC.92 | Bonded bands on 15, 25 for derotating them. Cemented bands on 26 to help the rotation of 25. |
| DEC.92 | Activated the coil on 25. New power chain on 15. |
| APR.93 | Removed bands on 25, 26. .016 Australian with intrusion step for the central. |
| SEP.93 | Cemented band on 15 and 46. Bonded bracket on 35 and he usually .018 in the upper arch with intrusion steps for the front. |
| SEP.93 | Tubes on 47 and 37 .016 x .022 with elastics. |
| NOV. 93 | .016 x .016 with intrusion step distal to the laterals. |
| NOV.93 | Added sweep in the lower arch. |
| MAR.94 | Upper arch:Increased step an sweep..016 x .022 Nitinol. |
| MAY.94 | Lower arch: .016 x .022 rectangular wire with sweep. |
| NOV.94 | Upper arch:Contraction arch: .016 x .022. |
| FEB.95 | .016 X .016 with intrusion steps distal to the upper lateral |
| MAR.95 | Class III elastics on the right side to mesialize the upper right segment. |
| APR.95 | Class II elastic on the left and class III on the right |
| MAY.95 | New contraction arch: .016 x .022 rectangular arch. |
| MAY.95 | .016 Australian with steps distal to laterals. Continuous Power chain from 16 to 26 to close residual spaces. |
| JUN.95 | Debonded both arch Upper arch: 2-2 retainer and Hawley plate. Lower arch 3-3 |
Fixed appliance: 4 years, 5 months.
|
 The main goals of treatment were:
The main goals of the treatment objectives were
fulfilled. |
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