This document discusses class I malocclusion and its management. It defines occlusion and class I occlusion. Class I malocclusion occurs when the molar relationship is class I but the line of occlusion is incorrect. Common causes include genetic and developmental factors. Bimaxillary protrusion is the most common type, characterized by maxillary and mandibular anterior proclination. Management depends on the specific malocclusion, and may include appliances, extractions, and in severe cases, orthognathic surgery.

1. PRESENTED BY:
HAFSA SARA ZUBAIR
BDS

2. OBJECTIVES:
• OCCLUSION
• CLASS I OCCLUSION
• CLASS I MALOCCLUSION
• LINE OF OCCLUSION
• CAUSES OF CLASS I MALOCCLUSION
• BIMAXILLARY PROTRUSION
• FEATURES OF BIMAXILLARY
PROTRUSION
• FEATURES OF CLASS I MALOCCLUSION
• DIAGNOSIS
• MANAGEMENT OF CLASS I

3. WHAT IS OCCLUSION ?
“ Occlusion is the relationship of the
maxillary and mandibular teeth when the jaws
are in fully closed position.”

4. CLASS I OCCLUSION

5. CLASS I MALOCCLUSION
• Normal relationship of the molars, but
line of occlusion incorrect
o Malposed teeth
o Rotations
o Others

6.  FOR UPPER ARCH :
 Smooth curve passing
through the central fossa
of each upper molar and across
the cingulum of upper canine
and incisor teeth.
o FOR LOWER ARCH:
• The same line runs along
the buccal cusp and incisal
edges of lower teeth.

7. CAUSES OF CLASS I
MALOCCLUSION
DEVELOPMENTAL GENETIC ENVIRONMENTAL

8. INCLUDES:
 Congenitally missing teeth.
 Malformed teeth.
 Supernumerary teeth.
 Impacted teeth
 Ectopic eruption

9.  Plays major role for malocclusion where
there is discrepancy between the size
of jaws and size of teeth.

10. CAUSED BY:
Injuries which has two types:
 BIRTH INJURIES:
› Fetal moulding
› Trauma during birth from usage of forceps.

11.  INJURIES THROUGHOUT LIFE:
Trauma to teeth can lead to:
 Damage to permanent tooth bud.
 Premature loss of primary teeth leads
to permanent tooth movement.
 Direct injury to permanent teeth.

12. MOST COMMON FORM :
• BIMAXILLARY PROTRUSION

13. WHAT IS BIMAXILLARY PROTRUSION ??
The patient exhibits a normal class I molar
relationship but the dentition of both the upper
and lower arches are forwardly placed in relation
to facial profile.

14. FEATURES

15. FEATURES OF BIMAXILLARY
PROTRUSION
EXTRAORAL
FEATURES
CEPHALOMETRIC
FINDINGS
INTRAORAL
FEATURES

16.  Decreased
nasolabial angle
due to proclined
maxillary anteriors.
o Shallow mentolabial
sulcus due to
proclined mandibular
anteriors.

17. oLips may be
incompetent.
oConvex facial
profile.
CONT…

18.  Maxillary and
mandibular anterior
proclination.
 Class I molar
relationship (2)

19.  Class I canine
relationship (may
be)

20.  Spacing between
teeth. (may be)

21.  Decreased
interincisal angle.
 Increased incisor
mandibular plane
angle

22.  Increased SNA and SNB, if
there is prognathism of jaws.

23. FEATURES OF CLASS I
MALOCCLUSION
INTRAORALEXTRAORAL

24.  Straight profile.
 Harmonious face

25.  Class I molar
relationship (2)
 Class I canine
relationship (3)

26.  Class I incisor
relationship
 Spacing

27.  Crowding
 Bimaxillary protrusion

28.  Cross bite
 Open bite

29.  Deep bite
 Rotations

30. • HISTORY
• CLINICAL EXAMINATION
• STUDY MODELS
RADIOGRAPHS:
• OPG
• LATERAL CEPHALOGRAM
DIAGNOSIS:
• HISTORY
• CLINICAL EXAMINATION
• STUDY MODELS
RADIOGRAPHS
• OPG
• LATERAL CEPHALOGRAM

31. MANAGEMENT OF CLASS I
MALOCCLUSION

32. MANAGEMENT :
AIMED AT CORRECTION OF
DISTURBANCE IN LINE OF OCCLUSION
LEADING TO
• CROWDING
• SPACING
• OPEN BITE
• CROSS BITE
• DEEP BITE
• ROTATIONS
• BIMAXILLARY PROCLINATION

33. ‘’CROWDING’’

34. ‘Is defined as malalignment of teeth caused by inadequate
space.’
• Occurs due to GENETIC or ENVIRONMENTAL factors.
• Classified as:
Mild crowding --- less than 4mm per arch.
 Moderate crowding --- 5 to 9mm per arch.
 Severe crowding --- 10mm or more per arch.
Before carrying out treatment, following aspects
should be considered.
 Degree of crowding.
 Site and position of crowding.
 Patient’s age.

35. • MILD CROWDING
• Resolves without extraction.
• Proximal stripping
• Alignment of teeth by labial bow or z-
spring.

36. MODERATE CROWDING
• Arch expansion (quad helix applaince)
• Distalization of molars.

37. • Extraction of all 1st premolar
• Retract canine by canine retractor
• Align anteriors by labial bow.
• Retention by hawley’s retainer.

38. SPACING
LOCALIZED GENERALIZED

39. ‘Gaps between two teeth or many teeth’
• Can be:
• Localized (space present in localized
regions or areas)
• Generalized (space present in entire
arch)

40. • Results from hypodontia along with small teeth
(microdontia) in well developed arches.
• IN CASE OF MICRODONTIA:
• Eliminate spaces between anteriors, leaving a
space between canine and 1st premolar.
• Give prosthesis or implant.

41. • It results from loss of tooth due to trauma, or
hypodontia or due to presence of midline diastema.
 Intervention is required in cases with:
Diastema greater than 3mm, no space for perm. lateral
incisors to erupt.
 Permanent canines have erupted, diastema still
present.
 Labial frenum has not migrated to labial attached
mucosa.
 Congenitally missing incisors.
 Presence of supernumerary teeth.

42.  Eliminate cause: i.e. high labial frenum attachment.
 Removable appliance
• Finger spring
• Finger spring with labial bow
• Split labial bow
 Frenectomy
 Implants
Fixed appliances:
Pin and tube appliance

43. CROSS BITE

44. ‘Refer to a condition where one or more
teeth may be abnormally bucally or lingually
with reference to the opposed tooth or teeth.’
(GRABER)

45. ANTERIOR
CROSS BITE
SINGLE
TOOTH
MULTIPLE
TEETH
POSTERIOR
CROSS BITE
SINGLE
TOOTH
UNILATERAL
BILATERAL

46.  ANTERIOR CROSS BITE:
 SINGLE TOOTH:
• Z- spring
 MULTIPLE TEETH:
• Expansion screw

47.  POSTERIOR CROSS BITE:
 SINGE TOOTH:
• Cross-elastics
CROSS ELASTICS

48.  UNILATERAL CROSS BITE:
 Functional appliance
 Quad helix
 W arch
 Coffin spring
QUAD HELIX
W- ARCH
COFFIN SPRING

49.  BILATERAL CROSS BITE::
• Quad helix
• W arch
• RME by hyrax screw
Hyrex screw

50. OPEN BITE

51. OPEN BITE
‘ Open bite is the failure of a tooth or
teeth to meet antagonists in the opposite arch.’

52. TYPES OF OPEN
BITE
SIMPLE ANTERIOR
OPEN BITE
SIMPLE POSTERIOR
OPEN BITE
COMPLEX OR
SKELETAL OPEN
BITE

53. MANAGEMENT
• SIMPLE ANTERIOR OPEN BITE:
o Due to digital sucking.
o MIXED DENTITION:
o Habit breaking by tongue spikes
o Arch expansion

54. o LATE MIXED DETITION AND EARLY
PERMENANT DENTITION:
oHabit breaking.

55. • SIMPLE POSTERIOR OPEN BITE: (RARE)
o CAUSES:
o Ankylosed primary molars
o Lateral tongue thurst
o EARLY TREATMENT:
o Removal of ankylosed primary tooth.

56. • COMPLEX OR SKELETAL OPEN BITE:
o EARLY MANAGEMENT:
o Bionator
o Frankel appliance
o ADULT SKELETAL OPEN BITE:
o Orthognathic surgery

57. DEEP BITE

58. ‘condition of excessive overbite, where the
vertical measurement b/w maxillary and mandibular
incisal margins is excessive when the mandible is
brought into centric occlusion.’ (GRABER)

59. • GROWING AGE:
o Anterior bite planes
• INTRUDE ANTERIORS BY:
o Fixed appliance
o J. hooks vertical pull headgear
• Erupt posterior
• NON GROWING AGE:
o ORTHOGNATHIC SURGERY
o Lefort 1

60. BIMAXILLARY
PROTRUSION

61. MANAGEMENT
• Extract all 1st premolars.
• TREATMENT DEPENDS UPON ANGULATION OF
CANINE:
o DISTALLY INCLINED CANINE:
o Retract canine and align incisors using
retainer.
o MESIALLY INCLINED CANINE:
o Fixed appliance

62. ROTATIONS

63. • SINGLE TOOTH:
• REMOVABLE APPLIANCES:
• Double cantilever spring
• Labial bow
• MULTIPLE ROTATIONS:
• FIXED APPLIANCE
• SEMI- FIXED APPLIANCE:
• High labial bow with t- spring
Double cantilever
spring
High labial bow
T spring

64. • CONTEMPORARY ORTHODONTICS BY
WILLIAM R. PROFFIT
• HANDBOOK OF ORTHODONTICS BY
ROBERT E. MOYERS
• ORTHODONTICS PRINCIPLE AND
PRACTICE BY BASAVARAJ PHULARI
• GOOGLE