Antero-Posterior Discrepancies Flashcards
The class II malocclusion is among the most common developmental
anomalies with a prevalence of around –% in the general
population
* Affecting –% of all orthodontic patients in the U.S.A
30
33
class 2
This anomaly can be divided into different categories
(3)
- Maxillary excess
- Mandibular deficiency
- Combination
class 2
The etiology may be of (2) origin
skeletal or dental
The class II malocclusion is the most frequent problem presenting
in the
orthodontic practice
The etiology of class II malocclusion has been linked to (2) factors
hereditary
and environmental
Diagnosis & Clinical
Features
* Class II malocclusions may be identified by precise clinical
evaluation
* Class II malocclusions may reflect:
(3)
- Maxilla-Mandible disharmony with underdevelopment of mandibular
growth - Dental disharmony (Angle classification)
- Combination
Diagnosis & Clinical
Features
*class 2 molar relationship
Maxillary first molar in a mesial position in relation to the
mandibular first molar (distocclusion
skipped
Two different types of Class II malocclusions
* Class II Divivion1:
* Class II Division 2:
Convex profile, mandibular retrognathism, variable
facial height, increased overjet (proclined maxillary incisors)
Straight to convex profile, decreased lower facial
height, normal overjet, deep overbite, retroclined maxillary central
incisors, labially inclined maxillary lateral incisors
Class II Division 1
(4)
- In severe (skeletal) class II division 1, the lips
are usually incompetent - Proclination of upper incisors
- Increased overjet
- Narrow and tapered upper maxillary arch
Class II Division 2
(3)
- Vertical dimension is usually decreased in
comparison with Class II division 1 - Dental crowding is created by retroclination
of the maxillary central incisors - Deep overbite caused by the over eruption
of the maxillary central incisors and lower
incisors
Skeletal class II malocclusion components may be classified by:
(2)
- Maxillomandibular relationship
- Vertical discrepancy
- Maxillomandibular relationship
- Mandibular retrognathism, midface protrusion or both
- Vertical discrepancy
- Anterior upper face height often greater than normal, and steep
occlusal plane
Treatment strategies of class II
malocclusion are categorized based on:
*status
growing and Non‐growing status of
patients.
Growing patients: Ideally, treatment of
Class II malocclusions should focus first
on improving the — discrepancy
* Using —while the
individual is still growing. (Growth
Modification)
skeletal
Functional Appliances
Treatment
* In adults, repositioning of the maxilla and mandible can be achieved with:
(2)
- Orthognathic surgery.
- Dentoalveolar compensation alone.
- Orthognathic surgery.
- Adjusting the position of both in relation to the cranial base in the three
dimensions and improving overall facial esthetics.
- Dentoalveolar compensation alone.
*Camouflage dental treatment.
Both removable functional appliances and headgear therapy depend on the
cooperation of the patients.
Among the different removable appliances, Twin‐block is used more often,
which can efficiently (3)
promote mandibular growth, restrict further forward
growth of the maxilla, and improve skeletal relationships in growing
skeletal class II individuals with mandibular retrusion.
The key differences between removable and fixed appliances are
different —, and also optimal
treatment timing (before puberty growth vs. at or after puberty spurt)
and direction of further growth
working hours (intermittent vs. continuous)
Dental changes with — appliances including — and — were more significant
than skeletal changes when compared to — appliances
fixed
mesial movement of
lower molars
proclination of lower incisors
removable
Late Management
Class II malocclusions
* In contrast to growing patients, limited range of treatment
modalities can be used for adult cases with class II skeletal and
dental malocclusions.
* Depending on the severity of malocclusion:
(2)
- Class II elastics, compensatory extractions.
- maxillary premolars and/or mandibular premolars
- — surgical modalities may be used to alleviate the
functional and esthetic problems associated with this type of
malocclusion.
Orthognathic
Orthognathic surgery:
Mandibular advancement with or without maxillary impaction (
Class II openbite)
- The proper — orthodontic tooth movements and
—- are essential to maximize the amount of
discrepancy correction during surgery. - Although orthognathic surgery could be an efficient treatment
modality in severe class II patients, both the — of the surgery and
the — of undergoing surgery normally prevent patients from
choosing this treatment option.
presurgical
alignment of arches
cost, fear
Class — malocclusion is the most difficult and complex orthodontic
problems to treat.
III
- Skeletal Class III malocclusion is characterized by:
(3)
- Mandibular prognathism
- Maxillary deficiency
- Some combination of these two features
- The prevalence of Class III malocclusion varies among different
ethnic groups. - The prevalence in Caucasians ranges between
- A high prevalence has been reported in Asians —% of Japanese .
1% and 4%.
20
Like other types of malocclusions, the etiology of class III
malocclusion has been linked to (2)
factors
hereditary and environmental
More than half of all skeletal Class III malocclusions are
reported to result from — deficiency.
maxillary
More precisely, the incidence of Class III malocclusions
suffering from maxillary deficiency was reported to be –%
65–67
class 3
Diagnosis & Clinical
Features
* Extraoral features :
(3)
- Concave profile.
- Anterior facial divergence.
- Prominent lower third of face/chin.
class 3
intraoral features :
(4)
- Class III molar and canine relationship.
- Narrow upper arch.
- Decreased or reverse overjet.
- Crowding in upper arch
Etiology of Class III
* The etiology is associated with environmental and genetic
factors.
* The etiological factors of this malocclusion have been
classified into two groups:
(2)
- Skeletal.
- Dental.
- Skeletal.
- Hypoplastic maxilla. Hyperplastic mandible. Combination
- Dental.
- Anterior crossbite of functional origin
Functional Class III
* Pseudo-Class III characterized by:
- Anterior crossbite
- CR-CO Shift
- Not a true Class III malocclusion if corrected early
Anterior crossbite
* Due to a
forward functional displacement of the mandible
Functional Class III
Treatment
* In most cases, — is the main
etiological factor of a pseudo-Class III malocclusion.
* Correction of the anterior crossbite must be carried out as
soon as it is detected to increase the orthopedic effects,
thereby increasing the long-term stability of the treatment
results.
retroclined maxillary incisors
Manipulate the condyles in their physiologic rest position.
If the occlusion is end to end it is probable that the crossbite is
—
functional
Maxillary Expansion-Protraction face mask
Goals:
Expand upper jaw to accommodate the lower dentition .
Apply traction to the maxilla to reposition it more anteriorly.
Slow down growth of mandible
- A facemask attached to a maxillary expansion appliance to promote anterior
maxilla repositioning by inducing growth at the —
maxillary sutures
The chance of true skeletal change appears to decline beyond age –, and the
chance of clinical success declines at age —
8
10 to 11
Late Management
Class III malocclusions
* The principles involved in the comprehensive treatment of Class III
dentoalveolar malocclusions are:
(4)
- Relief of crowding
- Level and align arches
- Increase overbite and overjet
- Compensation by over proclination of upper incisors and retroclination
of lower incisors
Late Management
Class III malocclusions
* In cases with moderate or severe Class III anteroposterior skeletal
discrepancies, a combination of (2) at the completion of skeletal growth (earlier in females than
males) will be required to create an acceptable and stable Class I
occlusion.
* Usually, an — repositioning is done
* More rarely a —
orthodontic treatment and orthognathic
surgery
anterior and vertical maxillary
mandibular set back
Late Management
Class III malocclusions
* — orthodontic treatment usually involves to align the
maxillary and mandibular arches, in order that they will co-
ordinate when their respective skeletal bases have been surgically
repositioned. (Decompensation)
* A short period of orthodontic treatment (ideally less than 6 months)
is often required — surgery to finish and detail the occlusion.
Presurgical
after
