Notes from Orthodontics

1. DR. SARANG SURESH HOTCHANDANI
Treatment
of Class III
Problems A class III malocclusion on a skeletal class 1 base with
a significant forward mandibular displacement is
sometimes referred to as a ‘pseudo class III
malocclusion’, because the incisor relationship does
not reflect the underlying skeletal relationship.
 Class 3 incisor relationship includes, malocclusion
where lower incisor edge occludes anterior to
cingulum plateau of upper incisors.
Etiology of Class III
Malocclusion
 Skeletal Class III is most common cause with resulting
following features
o Increased mandibular length
o Forward positioning of glenoid fossa
o Reduced maxillary length
o Short cranial base
o Reduced cranial base angle
 Skeletal class III often have increased vertical
dimension.
 They are also associated with unilateral or bilateral
cross bite, which is due to following reasons;
o Narrow maxilla
o Broad mandible
o Antero posterior skeletal discrepancy
o Vertical maxillary deficiency
o Transverse deficiency
 Other Rare Causes include;
o Cleft Palate

2. DR. SARANG SURESH HOTCHANDANI
o Craniofacial syndromes
 Crouzon syndrome
 Sometimes patients have large tongue which can
broad the lower arch resulting increase in cross bites &
Proclination of lower incisors worsening the class III.
OCCLUSAL FEATURES of
SKELETAL Class III
 Anterior cross bite
 Buccal cross bite
 Maxillary arch crowding (common)
With favourable soft tissues environment, this skeletal class III exhibit dento alveolar
compensation in which soft tissues cause tilting of upper & lower incisors towards
each other, so that the incisor relationship is less severe than underlying skeletal
class III.
Factors to be Considered during Treatment of Skeletal Class III
patient
Patient Concerns  Dental problem alone can be managed with orthodontic treatment alone.
 Facial/functional problems will require orthognathic surgery.
Motivation for
treatment
o Good dental health and motivation are required for complex treatment.
Severity of skeletal
discrepancy
o A mild/moderate skeletal discrepancy may be treated with orthodontic camouflage
if the patient can achieve edge to edge occlusion.
o A severe skeletal discrepancy can be treated comprehensively with orthodontics &
orthognathic surgery.
Remaining growth o If correction is done before end of pubertal growth, it will relapse due to differential
growth of mandible. That’s why it should be continued after the stoppage of
pubertal growth.
Degree of dento
alveolar compensation
o In preexisting dento alveolar compensation we cannot perform camouflage
Ability to achieve edge
to edge
o An ability to achieve edge-to-edge favors orthodontic camouflage as it indicates that
less incisor movement is required for correction than suggested by the size of
reverse overjet in centric occlusion
Depth of overbite o A deep overbite offers scope for camouflage by downwards and backwards rotation
of the mandible (e.g. facemask) and improves stability of anterior cross bite
correction.
Figure 1 Dento Alveolar Compensation

3. DR. SARANG SURESH HOTCHANDANI
Anteroposterior & Vertical Maxillary Deficiency
 Effect of antero posterior deficiency in contribution to skeletal class III is direct on mandible
 While, effect of vertical deficiency in class III is indirect on mandible
o Cause rotation of mandible upward & forward, produce appearance of mandibular prognathism.
Methods to treat both these maxillary deficiencies;
 Frankel’s FR – III Functional appliance
 Reverse pull headgear (facemask)
 Class III elastics.
FR – III Functional Appliance
 Should be only used in extremely mild conditions.
 Theoretically this appliance; stretches the soft tissue at the base of upper lip via lips pads, attempting to stimulate
forward growth of the maxilla by stretching the maxillary periosteum while
maintaining the mandible in its most posterior or retruded position.
 However, following changes occur for correction of skeletal class III with
this appliance.
o Eruption of maxillary molars mesially
 Blocking the eruption of lower molars vertically & antero
posteriorly.
o Facial tipping of maxillary anterior teeth & retraction of
mandibular anterior teeth.
o Rotation of occlusal (shown in pic)
 due to more eruption of upper molars than lower molars.
o Downward & backward rotation of mandible.
 Decreasing the chin prominence
 Increase facial height
 This appliance has long treatment & retention periods that require excellent compliance.
Reverse – Pull Headgear (Facemask)
 Face mask or the reverse-pull headgear is an extra oral traction appliance used for correction of skeletal class III
malocclusion.
 It was popularized by Delaire in the 1960s.
 Indications;
o CLASS III
Figure 2 FR - III

4. DR. SARANG SURESH HOTCHANDANI
Facemask moves maxilla forward by inducing
growth at the maxillary sutures.
A. This Delaire-type facemask offers good stability when used for maxillary
protraction. It is rather bulky and can cause problems with sleeping and wearing
eyeglasses. With even modest facial asymmetry, it can appear to be ill-fitted on
the face. Note the downward and forward direction of the pull of the elastics.
B. This rail-style facemask provides more comfort during sleeping and is less
difficult to adjust. It also can be adjusted to accommodate some vertical
mandibular movement. Both types can lead to skin irritation caused by the plastic
forehead and chin pads. These occasionally require relining with an adhesive-
backed fabric lining for an ideal fit or to reduce soft tissue irritation. Clinical experience indicates that some children will prefer one type
over the other, and changing to the other type of facemask can improve cooperation if the child complains.
 Protraction of maxilla should be performed at the early age, because age of patient is critical variable in forward
movement of maxilla with orthodontic appliance.
True skeletal change decline beyond age 8, while, the chances of clinical success
begins to decline at age 10 – 11.
Facemask treatment is most suited for children with minor – moderate skeletal
problems. This device is to be used in children who have true maxillary problems in Class
III.
 Defer facemask treatment until permanent 1st molar & incisors have erupted.
o Molar give anchorage
o Incisors will provide inclination for correction of overjet.
 Facemask is attached intra orally with maxillary removable splint or with banded expander.
o These both appliances contain hooks in premolar – canine region for attachment of elastics as shown in
figure above.
 Facemask provide 350 – 450 grams of force per side when worn for 12 – 14 hours per day.
 Elastic are placed in a slight downward direction b/w intra oral attachment and facemask to correct vertical
maxillary deficiency along with antero posterior deficiency.
A maxillary removable splint is sometimes used to make the
upper arch a single unit for maxillary protraction.
A. The splint incorporates hooks in the canine-premolar
region for attachment of elastics and should cover the
anterior and posterior teeth and occlusal surfaces for
best retention.
B. Note that the hooks extend gingivally, so that the line
of force comes closer to the center of resistance of the
maxilla. Multiple clasps also aid in retention. If
Figure 3 A. Delaire-type facemask B. rail-style facemask

5. DR. SARANG SURESH HOTCHANDANI
necessary, the splint can be bonded in place, but this causes hygiene problems and should be avoided if possible
for long-term use.
C. and D, a banded expander or wire splint also can be used for delivery of protraction force. It consists of bands on
primary and permanent molars or just permanent molars connected by a palatal wire for expansion and hooks on
the facial for facemask attachments.
If the maxilla is narrow, palatal expansion is anticipated, then expansion device will act as splint for the attachment of
facemask
EFFECTS of FACEMASK
 Clockwise rotation of mandible – downward & backward rotation.
o increase lower facial height (long face).
o That’s why facemask is contraindicated in long face patients.
 Downward rotation of posterior maxilla and anterior open bite (see diagram below)
 Forward movement of maxilla and Proclination of maxillary teeth.
 Correction of cross bite— both posterior as well as anterior.
With the splint over the maxillary teeth and forward pull from the facemask, the hooks on the splint should be elevated. Even so, the line of force is likely
to be below the center of resistance of the maxilla, so some downward rotation of the posterior maxilla and opening
of the bite anteriorly is anticipated
Skeletal Anchorage
With the appliances mentioned above for maxillary protraction, there is a major side effect
as mentioned; although we want to cause maxillary protraction but there is more dental
protraction than maxilla.
So, before advent of bone screws or miniplates, primary canines were deliberately
ankylosed so that they can act as “natural implants” to which facemask or Class III elastics
can be attached & support can be taken be taken from these teeth for Proclining the
maxilla in class III patients without changes occurring in teeth.
if a child with maxillary retrusion has spontaneous ankyloses of primary molars, the splint of facemask can be attached
to that tooth for above mentioned biomechanical advantage.
This dental change can be prevented & maxillary Proclination can be magnified in one of two ways in which face mask
is attached with;
01) Miniplates at the base of zygomatic arch or in anterior maxilla.
02) Bone anchors/screws above the incisors
For patients approaching adolescence i.e., about age 11 and old are better treated with bone screws for attachment of
facemask for Proclining the maxilla.
Another method of correcting the Class III problems is placement of bone supported miniplates bilaterally in maxilla
and mandible, to which class III elastics are attached.

6. DR. SARANG SURESH HOTCHANDANI
A maxillary-deficient child wearing Class III elastics to miniplates at the
base of the zygomatic arch and mesial to the mandibular canines. Note that
the patient is wearing a biteplate to open the bite until the anterior cross
bite is corrected, and that and that point of attachment for the lower left
miniplates has been repositioned with a piece of 21 × 25 steel wire in the
miniplates tube. Being able to move the point to which force is applied, of
course, is one of the advantages of miniplates.
Advantages of these Skeletal Anchorage & Class III
Elastics over the Extra Oral Appliances mentioned
above;
o Produce more skeletal change than dental change.
o Wearing extra oral appliances is not necessary.
o Full time application of force can be obtained.
Disadvantage is surgical placement & removal of miniplates or bone screws.
The minimum age for placement of placement of these bone screws is approx. 12 years
of age. Placement before this age weakens the bone because of low density of alveolar
bone at that age, and effect the eruption of permanent teeth placed under the bone.
There is relapse of class III treatment, remember it is because of excessive mandibular
growth.
Class III due to Mandibular EXCESS
They are difficult to treat because we cannot determine when the mandibular growth will stop.
Class III Functional Appliances in Tx. Of Excess, Mandibular Growth
 Functional appliances for patients with excessive growth does not restrain mandible growth but instead they cause
following effects;
o Rotate mandible downward & backward
o Guide the eruption of teeth (Camouflage)
 Upper posterior teeth erupt downward & forward
 Eruption of lower posterior teeth is restricted.
 Lingual tipping of lower incisors.
 Facial tipping of upper incisors.
 Functional appliances used in mandibular excess are like those which are used in maxillary deficiency mentioned
above, except that they don’t contain lip bumper.
Class III Functional AppliancesClass III Functional Appliances
Chin Cup with High Pull HeadgearChin Cup with High Pull Headgear
Class III elastics to Skeletal AnchorsClass III elastics to Skeletal Anchors

7. DR. SARANG SURESH HOTCHANDANI
Chin Cup Appliance
 Chin cap or chin cup is an extra oral orthopedic device, which exerts upward and backward force on mandible by
applying pressure to chin and thereby preventing its forward growth.
Chin Cup therapy changes the direction of mandibular growth by rotating the chin
downward & backward, making the chin less prominent by increasing anterior facial
height.
 Chin cup temporarily restrict the growth which will be overwhelmed by subsequent growth.
o Means thore time lae gowth khe stop karayeendo aa ta jeeyan future me growth the ta ooha excessive growth nazar na ache aen thori der
lae jeka growth stop karaeendas chin cup san ooha future je growth me dhakji wendi.
 In real meaning, chin cup causes following changes;
o Decrease the anteroposterior prominence of chin
o Increase the facial height.
o Lingual tipping of lower incisors due to pressure of the appliance on lower lip.
 This effect is undesirable.
 There are 2 Types of Chin Cup;
o Occipital pull chin cup
o Vertical pull chin cup
 Occipital pull chin cup
o Most commonly used type and derives anchorage from occipital region of head.
o Used in cases of class III malocclusion with mild-to-moderate prognathism.
 Vertical pull chin cup
o It is used to correct anterior open bite cases.
o Force magnitude and duration of wear (biomechanics)
o Force at the start of treatment: 150–300 g/side.
o After 2 months, force is increased to: 450–700 g/side.
o Duration to wear appliance to achieve desired results: 14 hours a day with a range of 10–16 hours.
Class III Elastics to Skeletal Anchors
class III elastics as mentioned in above topic of skeletal anchorage cause protraction of maxilla, but it was seen that
some effects of mandible also occur during elastics treatment as mentioned below.
 Posterior displacement of mandible at the condyle & posterior ramus.
For a child with sever prognathism orthognathic surgery at the end of growth period is
the best treatment.
THE END