ORTHODONTICS

1. MANAGEMENT OF
OPEN BITE AND
CROSS BITE
UNDER THE GUIDANCE OF
DR. MRIDULA TREHAN

2. OPEN BITE
 DEFINITION- Open bite is descriptive of
a condition where a space exists
between the occlusal/incisal surfaces of
maxillary & mandibular teeth in the
buccal or anterior segments when the
mandible is brought into habitual/centric
occlusion

3. CLASSIFICATION
 BASED ON LOCATION
 -Anterior open bite
Posterior open bite
 BASED ON TISSUES INVOLVED:
Dental
Skeletal

4. ANTERIOR OPEN BITE
 No vertical overlap between upper and
lower anteriors
 Skeletal anterior open bite
 Dental anterior open bite

5. FEATURES OF SKELETAL
ANTERIOR OPEN BITE
1) Increased anterior lower facial height
2) Steep mandibular plane angle
3) Long & narrow face
4) Incompetent lips
5) Increased gonial angle
INTRA-ORAL FEATURES
1) Gingival hypertrophy
2) Maxillary occlusal & palatal planes tip up
3) Mandibular occlusal plane canted downward

6. FEATURES OF DENTAL
ANTERIOR OPEN BITE
1) Proclined upper anterior teeth
2) Upper and lower anteriors fail to overlap each
other resulting in a space between upper and
lower anteriors
3) May have a narrow maxillary arch due to
lowered tongue posture associated with the
habit
4) Spacing between maxillary & mandibular
anterior teeth

7. ETIOLOGY OF ANTERIOR
OPEN BITE
1) Digit sucking habits
2) Lip andTongue habits
3) Airway obstruction
4) Abnormal skeletal growth pattern of maxilla &
mandible- Vertical growth in the molar region
not compensated by growth at the condyle or
posterior ramus

8. 5) Iatrogenic open bite- Poor mechanics
during fixed appliance treatment
resulting in extrusion of molars or
hanging palatal cusps.
6) Pathological open bite- Associated with
cleft lip and palate, acromegaly or
trauma to face such as condylar
fractures or fracture of maxilla

9. 7) Muscular dystrophy- Mandible rotates
downwards and backwards resulting in
increased anterior facial height and
excessive eruption of posterior teeth
leading to anterior open bite.

10. TREATMENT OF
ANTERIOR OPEN BITE
 REMOVAL OF CAUSE- Habits

11. MYOFUNCTIONAL
THERAPY
 FR IV
 Modified activator
 These appliances incorporate bite blocks
interposed between the posterior teeth
that have an intrusive action on upper
and lower posterior teeth
 Used in cases of skeletal anterior open
bite

12.  Modified bite blocks-
1) Spring loaded bite blocks- helical
springs placed both buccally and
lingually. Force of 450gm bilaterally
2) Repelling magnets

14. ORTHOPAEDIC
APPLIANCES
 Chin cup with vertical pull headgear
 High pull headgear

15. ORTHODONTIC THERAPY
 Fixed mechanotherapy in conjunction
with box elastics-cause extrusion of
upper and lower anteriors

16. SURGICAL CORRECTION
 Skeletal open bite in adults
 Le fort I osteotomy to impact maxilla
posteriorly

17. USE OF TAD’S
 Placed buccally between the roots of the
maxillary molars to help intrude the
maxillary posteriors.

18. RETENTION
 High relapse rate due to continued vertical
growth of maxilla and eruption of posterior
teeth.
 Directed towards intrusion or at least
prevention of eruption of maxillary posterior
teeth.
 Upper removable retainer with attached
headgear.
 Retainer with passive posterior bite blocks.
 Open bite activator or bionator.

19. POSTERIOR OPEN BITE
 Condition characterized by lack of
contact between the posteriors when
teeth are in centric occlusion
 Mostly occurs in a segment of the
posterior teeth

20. CAUSES OF POSTERIOR
OPEN BITE
i. Lateral tongue thrust/lateral tongue
posture
ii. Ankylosed/impacted posterior teeth that
fail to erupt to normal occlusal level

21. TREATMENT
 Removal of cause
 Habit-lateral tongue cribs
 Ankylosed- crowns are made

22. CROSS BITE
 DEFINITION(By Graber)-It refers to a
condition where 1/more teeth maybe
abnormally malposed buccally/lingually/
labially with reference to the opposing
tooth/teeth

23. CLASSIFICATION OF
CROSSBITE
 Based on location:
1.Anterior crossbite- single tooth
segmental
2.Posterior crossbite- unilateral
bilateral
 Based on nature of crossbite:
1.Skeletal crossbite
2.Dental crossbite
3.Functional crossbite

24. ANTERIOR CROSSBITE
 Defined as a malocclusion resulting from the
lingual position of the maxillary anterior teeth in
relationship with the mandibular anterior teeth.

25. POSTERIOR CROSSBITE
 Abnormal transverse relationship
between upper and lower posterior teeth.
Instead of mandibular buccal cusps
occluding in central fossae of maxillary
posterior teeth, they occlude buccal to
maxillary buccal cusps

26. CAUSES OF POSTERIOR
CROSSBITE
1. Narrow upper arch
2. Wide lower arch
3. Palatally displaced maxillary buccal
teeth
4. Buccally displaced mandibular buccal
teeth
5. Functional lateral shift of mandible
during closure of the mandible

27. BUCCAL NON-OCCLUSION
OR SCISSORS BITE
 Maxillary posteriors occlude entirely on
buccal aspect of mandibular posteriors

28. LINGUAL NON-OCCLUSION
 Maxillary posteriors occlude entirely on
lingual aspect of mandibular posteriors

29. SKELETAL CROSSBITE
 Anterior-small maxilla/backwardly placed
maxilla
-large mandible/prognathic
mandible
 Posterior-narrow upper arch

30. DENTAL CROSSBITE
 Due to localized disturbances such as
ectopic eruption of permanent teeth/over-
retained deciduous tooth/tooth material-
arch length discrepancy

31. FUNCTIONAL CROSSBITE
 Occlusal interference-deviation of
mandible during jaw closure –unilateral
posterior cross bite /pseudo class III

32. Difference between skeletal and
dental anterior crossbite
Skeletal anterior
crossbite
Dental anterior
crossbite
Etiology Mostly genetic and
hereditary
Lack of space,
crowding, over retained
deciduous teeth
Molar and canine
relationship
Class III Class I
Maxillary incisor
inclination
Proclined Upright or retroclined
Transverse discrepancy May be associated with
posterior crossbite in
some cases
Usually none
Sagittal discrepancy Significant antero-
posterior discrepancy
between the maxilla and
mandible
No significant
discrepancy between
the maxilla and
mandible

33. Skeletal anterior
crossbite
Dental anterior
crossbite
Mandibular growth
pattern
Often vertical (except in
cases of true
mandibular
prognathism)
Normal
Position of teeth Normally positioned Deflected tooth position
Number of teeth in the
crossbite
Segment crossbite Single mostly

34. ETIOLOGY OF CROSSBITE
1) Retained deciduous tooth
2) Arch length – tooth material discrepancy
3) Habits such as thumb sucking, mouth
breathing and lip biting
4) Retarded development of maxilla
5) Cleft lip and palate
6) Prognathic mandible
7) Retrognathic maxilla
8) Large mandible

35. 9) Congenital maxillary deficiency due to
prenatal pressure against the developing
fetal face.
10) Unilateral hypo or hyperplastic growth
of any of the jaws

36. FACTORS THAT INFLUENCE
TREATMENT OF ANTERIOR
CROSSBITE
1. Overbite
2. Space
3. Type of tooth movement
4. Maxillary incisor torque
5. Functional shift on closure of mandible
6. Number of teeth in crossbite

37. TREATMENT OF
ANTERIOR CROSS-BITE
 USE OF TONGUE BLADE
 Sufficient space

38. CATALANS APPLIANCE OR
LOWER ANTERIOR INCLINED
PLANE
 INDICATIONS:
i. If the maxillary tooth is in lingual cross-
bite
ii. Normal/excessive overbite
iii. Adequate space

40.  Made of acrylic or cast metal
 1st appointment-impression
 Should incorporate a tooth and a half on either
side of the cross bite area.4 mandibular
incisors are sufficient
 Should be at an angle of 45 degree to occlusal
plane
 Should only contact maxillary tooth in cross
bite

41.  2nd appointment-try appliance in patients
mouth
 Bite should not be opened more than 4-5
mm
 Appliance is cemented
 Liquid food
 Correction effected in 7-14 days
 Next appointment after 7 days

42.  3rd appointment-remove appliance if
cross bite has been corrected
 Do not leave appliance in mouth for more
than 6 weeks

43.  ADVANTAGES:
1) Ease of fabrication
2) Rapidity of correction
3) Lack of soreness or looseness of teeth
4) Rarity of relapse

44.  DISADVANTAGES:
1) Strong limitation on diet
2) Creation of temporary speech defect
3) If appliance used for more than 6 weeks
leads to anterior open bite
4) Appliance may need frequent cementation
5) Imperfect alignment of malposed tooth when
appliance is removed

45. USE OF DOUBLE
CANTILEVER OR Z SPRING
 If there is deep bite use a posterior bite
plane

46. TREATMENT OF SKELETAL
ANTERIOR CROSS BITE
DURING GROWTH PERIOD
 If maxilla is retropositioned use a
protraction face mask or reverse
headgear
 If mandible is prognathic use a chin cup

47.  Fixed appliance for treatment of anterior
crossbite- Preferred

48. TREATMENT OF POSTERIOR
CROSSBITE
 Factors influencing treatment:
1. Buccolingual tooth inclination- Favorable
if inclined palatally.
2. Etiology- Dental or skeletal
Unilateral or bilateral
3. Vertical changes

49.  CROSS BITE ELASTICS-For single tooth
cross bite

50.  COFFIN SPRING

51.  QUAD HELIX

52. RAPID MAXILLARY
EXPANSION

53.  REMOVABLE APPLIANCES
INCORPORATING JACKSCREWS

54.  FIXED APPLIANCES