Interceptive Orthodontics

Interceptive OrthodonticsIntroduction:-A malocclusion, if detected as

soon as possible, can be eliminated or made less severe, by initiation of interceptive orthodontic procedures.

An interceptive procedure undertaken at the right time can, therefore , either eliminate developing malocclusion or make it less severe, so as to allow corrective orthodontics to deliver a stable & conservative result.

• Defined : Interceptive orthodontics as that phase of the science and art of orthodontics employed to recognize and eliminate potential irregularities and malpositions in the developing dentofacial complex.

The procedures undertaken in interceptive orthodontics include:-

1. Serial extraction.2. Space regaining.3. Correction of developing cross bite.4. Oral habit elimination.5. Muscle exercises.6. Interception of developing skeletal

malocclusion.7. Removal of soft tissue or bony barrier to

enable eruption of teeth.

1) Serial extraction: • Is an interceptive orthodontic procedure

usually initiated in early mixed dentition .• It is corrected by a procedure that include

planned extraction.• Extraction of certain deciduous teeth & later

specific permanent teeth in orderly sequence.

• Pre-determined pattern to guide the erupting permanent teeth into amore favorable position.

History :• Kjellgren in 1929 used the term serial

extraction.• Nance during 1940 popularized this technique

in U.S.A. & termed it planned & progressive extraction.

• Hotz in 1970 called such a procedure ‘Active supervision of teeth by extraction’.

Rationale : is based on two basic principlei. Arch length- tooth material discrepancy.ii. Physiologic tooth movement.

Indication :1. Class-I malocclusion showing harmony

between skeletal & muscular system.2. Arch length deficiency-following factors.• Absence of physiologic spacing.• Unilateral / bilateral premature loss of

deciduous canine with mid-line shift.• Malpositioned or impacted lateral incisors that

erupt palatally out of the arch.• Localized gingival recession in the lower

anterior region is a characteristics feature of arch length deficiency .

• Ectopic eruption of teeth. • Mesial migration of buccal segment. • Abnormal eruption pattern & sequence.• Lower anterior flaring. • Ankylosis of one or more teeth.3. Growth is not enough to overcome the

discrepancy between tooth material & basal bone.

4. Patient with straight profile & pleasing appearance.

Contra-indication:• Cl-II & CI-III malocclusion with skeletal

abnormalities.• Spaced dentition.• Anodontia / Oligodontia.• Open bite & Deep bite.• Middle diaestema.• Cl-I malocclusion with minimal space

deficiency.

• Unerupted malformed teeth e.g. dilaceration.

• Extensive caries or heavily filled first permanent molar.

• Mild disproportion between arch length & tooth material that can be treated by proximal stripping.

Advantage of serial extraction :• More physiologic treatment as teeth are

guided into normal position using physiologic forces.

• Duration of fixed treatment is reduced. • Health of investing tissues is preserved.• Lesser retention period is required.• Result are more stable.

Disadvantage :• Good clinical judgment is required. no single

approach can be universally applied.• Treatment time is prolonged over 2-3 years.• Patient cooperation is very important.• Tendency to develop tongue thrust as

extraction spaces gradually.• Extraction of buccal teeth causes deepening of

the bite.• Residual spaces can remain between the

canine & 2nd premolar.

Diagnostic procedure:• Study models.• Radiographs.• Photographs.

Procedure: Three of the popular method are-

a.Dewel’s method.b.Tweed’s method.c.Nance method.

Dewel’s method

• 3 step serial extraction procedure.• 1st deciduous canines are extracted.• Deciduous 1st molar extracted a year later.• Followed by extraction of erupting 1st premolar.

Tweed’s method/Nance method

• Method involves the extraction of deciduous 1st molar around 8 year of age.

• Followed by the extraction of the 1st premolar & the deciduous canines.

2.Space regaining:• Primary molar is lost early & space

maintainers are not used.• Reduction in arch length by mesial

movement.• Preferably undertaken at an early age prior

to the eruption of 2nd molar.Divided into two broad groups.a. Fixed appliances.b. Removable appliances.

a. Fixed appliances.i. Gerber spacer regainer. ii. Jack screw space regainer. iii. Open coiled space regainer. [ Herbst space regainer ]

b. Removable appliances.• upper/ lower Hawley’s appliance with helical

spring.• Hawley’s appliance with spilt acrylic dumb-

bell spring.• Hawley’s appliance with slingshot elastic.• Hawley’s appliance with palatal spring.• Hawley’s appliance with expansion screws.

3. Correction of anterior & posterior crossbite.• Corrected as soon as they are detected .• Better to treat them as the permanent teeth

begin to erupt.• Easier to bring about changes in the mixed

dentition stage.• Unilateral / bilateral.• True / functional or combination of two.• Could lead to a skeletal malocclusion.• Which would require corrective orthodontic

treatment later on.

• Common appliances used in the correction of crossbite are –

-Tongue blade therapy-Inclined planes-Composite inclines-Hawley’s appliance with Z spring -Quad helix appliance .

TONGUE BLADE THERAPY

4. Control of abnormal habit: • Habit in the orthodontic sense refer to certain

actions involving the teeth & other oral or perioral structures .

• Which are repeated often enough by some patients to have profound & deleterious effect on position of teeth & occlusion.

• Habit that can affect the oral structures are, thumb sucking, tongue thrusting , mouth breathing, etc.

Thumb sucking:• Presence of this habit upto 21/2-3years is

consider quite normal.• Beyond 31/2-4years of age can have a

damaging influence on the dentoalveolar structure.

• Tongue thrust: Is defined as a condition in which the tongue makes contact with any teeth anterior to the molar during swallowing.

• Present with open bite & anterior proclination.• Intercepted by using habit breaker.• Trained & educated on the correct technique

of swallowing.

Mouth breathing :• Can be obstructive or habitual in nature.• Nasal obstructive such as nasal polyps ,nasal tumors,

chronic nasal inflammatory conditions & deviated nasal septum.

• Persistence of habitual oral breathing is an indication to use a vestibular screen to intercept the habit.

5.Muscle exercise :a. Exercise for the masseter muscle:• To strengthen the masseter muscle .• Clenching of teeth by the patient while counting to ten.• Repeat the exercise for some duration of time.

b. Exercise for the lip [circum oral muscles]i. Upper lip is stretched in the posteroinferior direction by

overlapping the lower lip .such muscular lip allow the hypotonic lips to form oral seal labially.

ii. Hypotonic lips can also be exercised by holding a piece of paper between the lips.

iii. Parent can stretch the lips of the child in the posteroinferior direction at regular interval.

iv. Swashing of water between the lips until they get tired .v. Massaging of the lips.vi. Use of oral screen with a holder-to exercise the lips.vii. Button pull exercise.viii. Tug of war exercise.

c. Exercise for the tongue:i. One elastic swallow.ii. Two elastic swallow.iii. Tongue hold exercise.iv. The hold pull exercise. 6.Removal of soft tissue & bony barriers:• Supernumeary teeth , over-retained &

ankylosed primary teeth are other possible causes of non eruption.

7. Interception of skeletal malrelations Interception of Cl-II malocclusions.• Excessive maxillary growth, deficiency in

mandibular growth or a combination of both.

• Maxillary growth can be restricted by use of face bow with head gear.

• Mandibular growth is usually treated by myo-functional appliances.

Interception of Cl-III malocclusions.• Mandibular prognathism, maxillary

retrognathism & combination of both.• Chin cup with head gear helps in

restriction of mandibular growth .• FR III or face mask therapy is used for

cases of maxillary deficiency.