calcium and it's metabolism.pptx

1. OCCLUSION – BASIC CONCEPTS IN
ORTHODONTICS
Presented by:
Dr. Vidhi R. Shah
1st Year PG
1

2. CONTENTS
• Introduction
• Definition and Terminologies
• Development of the concept of occlusion
- Fictional
- Hypothetical
- factual
• Factors and force determining tooth position
• Tooth alignment
- Line of occlusion
- Plane of occlusion
• Classification of occlusion
• Occlusal contact during mandibular movement
• Attritional Occlusion by Begg’s Hypothesis
• Andrew’s six keys to optimal occlusion
• Conclusion
• References
2

3. INTRODUCTION
3

4. • Jablonski 1982-
It is the relationship between all components of
masticatory system in normal function, parafunction and dysfunction
including the morphology and functional features of the contacting
surface of the opposing teeth and restoration, occlusal trauma,
neuromuscular physiology, psychophysiological state and the
diagnosis, prevention and treatment of functional disorders.
(Jablonski, Dictionary of Dentistry, by Stanley Jablonski-1992, p556, p472)
• Occlusion –
The relationship of maxillary and mandibular teeth when they
are in functional contact during activity of mandible - GPT
4
DEFINITION
The Glossary Of Prosthodontics Terms – GPT 8th Edition

5. • Ideal occlusion :-
- Preconceived theoretical concept
- Structural and functional relationship
- Ideal principles and characteristics
• Normal occlusion :-
- Class–I relationship in centric occlusion
• Physiological occlusion:-
- Deviates from ideal occlusion
- Well adapted to particular environment
- No pathologic manifestation
TERMINOLOGY OF OCCLUSION
5
Textbook of Fundamentals of Occlusion by Jonathan P. Wiens - 2015

6. • Functional occlusion:-
- Highest efficiency during excursive movements
• Balanced occlusion:-
- Balanced and equal contacts are maintained throughout the
arch
• Unilateral balanced occlusion:-
- All posterior teeth on a side contact
• Bilateral balanced occlusion:-
- All posterior teeth contact on working side
- One or more teeth on balancing side
6
Textbook of Fundamentals of Occlusion by Jonathan P. Wiens - 2015

7. • Centric occlusion:-
- Maximum intercuspation of posterior teeth
• Traumatic occlusion:-
- Abnormal occlusal stress
- Injury to periodontium
7
Textbook of Fundamentals of Occlusion by Jonathan P. Wiens - 2015

8. The fictional period
(Prior to 1900)
The hypothetical period
(From 1900 to 1930)
The factual period
(from 1930 to present)
8
DEVELOPMENT OF CONCEPT OF
OCCLUSION
The idea of development of occlusion can be traced
through fiction and hypothesis to fact
 The fictional approach –
 The hypothetical approach –
Textbook of Orthodontics Principles and Practice – 3rd edition by T. M. Graber

9. • Pioneers like Fuller, Clark and Imrie – antagonism, meeting
or gliding of teeth.
Eugene Talbot’s text :
- Concept of normal occlusion was a historical event and
passed in the decline of species, this hardly served as an
inspirator of those to follow who were helpful of preventing,
inspirating and treating developing malocclusion.
9
The fictional period
(Prior to 1900)
Textbook of Orthodontics Principles and Practice – 3rd edition by T. M. Graber

10. • Edward H. Angle in 1899 –
 This hypothesis stating that in the normal occlusion, it will
be seen that each dental arch describes a graceful curve and
all the teeth in the arches are so arranged as to be in harmony
in the same as well as opposite arch.
10
The hypothetical period
(From 1900 to 1930)
Textbook of Orthodontics Principles and Practice – 3rd edition by T. M. Graber

11. • Case - concept of apical base and divided dentofacial area
into four zones of movement.
• He was aware – role of nose and chin and their influence on
profile as term protrude and retrude in reference to the
relative position of teeth
11
Matthew Cryer and Calvin Case (1905)
Textbook of Orthodontics Principles and Practice – 3rd edition by T. M. Graber

12. • Bennett in 1908 – first suggestion of a functional analysis or
dynamic approach to occlusion.
12
Textbook of Orthodontics Principles and Practice – 3rd edition by T. M. Graber

13. • In 1930 – dividing the line between static and dynamic
concepts.
• Broadbent and Hans Planer in 1930 – roentgenographic
cephalometry which enabled to follow longitudinally the oro-
facial developmental pattern and formation, eruption and
adjustment of tooth.
• Factual period Functional period
• Planer – Emphasis on efficiency of masticating mechanism.
Physiological rest position
Vertical dimension
13
The factual period
Textbook of Orthodontics Principles and Practice – 3rd edition by T. M. Graber

14. Primary
factors Secondary
factors
14
FACTORS AND FORCE DETERMINING
TOOTH POSITION
Intrinsic forces – tongue and lips
Extrinsic forces – habits,
Orthodontic appliances
Forces – dental occlusion
periodontal membrane
Stomatognathic system
Eruption forces
Proffit – 1978

15. • Weinstein et al. and Edward Angle –
Major cause of malocclusion – genetic and environment factor
Produce a stable ideal occlusion - without extraction of teeth because
environment could be modified by orthodontic treatment
15
EQUILIBRIUM THEORY OF TOOTH
POSITION
Equilibrium theory revisited : factors influencing position of teeth- William R. Proffit
Edward H. Angle

16. • The alignment of the dentition –
complex multidirectional forces
• Labial to the teeth – light, constant
lingually directed forces by lips and cheeks
• On lingual surface – labially and buccally
directed forces by tongue
16
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

17. • Proximal contacts –
Maintain teeth position in normal alignment during
mastication.
• Occlusal contacts –
Prevent extrusion or over eruption of teeth and maintaining the
arch stability
17

18.  Intra-arch alignment –
18
TOOTH ALIGNMENT
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

19. 19
 Line of occlusion –
Textbook of Contemporary Orthodontics by William R. Proffit - 6th edition

20. 20
LINE OF OCCLUSION, LOCATION
AND POSITION

21. 21
A Detailed Consideration of the Line of Occlusion, Robert M Ricketts, The Angle Orthod,1978,48(4),274-281
LINE OF OCCLUSION -
CONGRUITY FACTORS

22. 22
 Plane of occlusion -
• A line drawn through all the buccal cusp tips and incisal
edges of the mandibular teeth then broadened into a
plane to include the lingual cusp tips and continuing
across the arch included the opposite side buccal and
lingual cusp tips.
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

23. 23
MESIODISTALAXIAL INCLINATION
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson
Lateral view

24. • The alignment of each tooth – for maximum resistance to
the functional loading.
• Long axis of each lower tooth - parallel to its individual
arc – closure around the condylar axis
progressive positions
• The cusp tips on curve is directly related to the condylar
axis by progressive series of tangents
24
THE CURVE OF SPEE - REVISITED
The curve of spee - revisited Am J Orthod Dentofac Orthop (1996;110:206-10.)

25. 25
BUCCOLINGUALAXIAL INCLINATION
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson
Significance of curve of wilson
• Resistance to loading
• The axial inclination of
posterior teeth is nearly
parallel with the strong
inward pull of the
internal pterygoid
muscles

26. • Relationship of teeth in one arch to opposite arch
• The length and width of maxillary arch – higher
• Arch length-
• Arch width-
26
INTER ARCH TOOTH ALIGNMENT
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

27. 27
Maxillary lingual cusps Central fossa of mandibular
teeth which protects the surrounding soft tissue.
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

28. • Based on mandibular position
• Based on relationship of 1st permanent molar
• Based on organization of occlusion
• Based on pattern of occlusion
28
CLASSIFICATIONS OF OCCLUSION
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

29. • CENTRIC OCCLUSION:-
• ECENTRIC OCCLUSION:-
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BASED ON MANDIBULAR POSITION
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

30. 30
TYPES OF CUSPS
Centric holding cusp / stamp cusp /
supporting cusp
Guiding cusp / shear cusp / non-
supporting cusp
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson

31. • Cusp - fossa occlusion / tooth to tooth-
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ARRANGEMENT OF TEETH
• Cusp – embrasure occlusion-
Management of Temporomandibular Disorders and Occlusion – 8th edition by Jeffrey P. Okeson
Ronald H. Roth’s orthodontic treatment goals
• Incisal guidance / Anterior guidance –
• Canine guidance -

32. 32
OCCLUSAL CONTACT DURING
MANDIBULAR MOVEMENT
Protrusive mandibular movement Retrusive mandibular movement

33. 33
Mediotrusive and Laterotrusive mandibular movement
Inner inclines of
lingual cusps

34. • Dr. P. R. Begg - 1954
34
ATTRITIONAL OCCLUSION BY
BEGG’S HYPOTHESIS
 Effects of attrition on the evolution of human teeth
A discussion of Begg’s attritional occlusion model as correct occlusion, Aug.Orthod.J. 11(3)March 1990
:190-194

35. • Normal occlusion – still not clear
• Lawrence F. Andrew’s – 120 non- orthodontic models
35
ANDREW’S SIX KEYS OF OCCLUSION
Andrew’s LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

36. 36
KEY – 1 MOLAR RELATIONSHIP
( INTER ARCH RELATIONSHIP)
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

37. • Long axis of tooth -
37
KEY-2 CROWN ANGULATION
• Gingival portion of long axis of the crown – placed distally
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

38. 38
KEY – 3 CROWN INCLINATION
( Mesial and distal view )
• Crown inclination ?
• Lingually placed crown – positive crown inclination
• Labially / buccally placed crown – negative crown inclination
Positive crown
inclination
Mild negative
Negative crown
inclination
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

39. • Rotated posteriors – occupy more space then normal
• Rotated anteriors – occupy less space
39
KEY – 4 ABSENCE OF ROTATION
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

40. • It is an essential – maintain the integrity of arch form
40
KEY – 5 PRESENCE OF TIGHT
CONTACTS
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

41. 41
KEY – 6 FLAT CURVE / CURVE OF SPEE
• Relatively flat
• Vertical distance – should not be exceed 1.5 mm
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

42. 42
REVERSE CURVE OF SPEE
• Creates excessive space
• Prevent displacement of a normal occlusion
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

43. 43
EXCESSIVE CURVE OF SPEE
• Restricts the amount of space available for upper teeth
• Preventing correct intercuspation
Teeth move towards mesially and distally
Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302

44. • Tooth size is actually the “seventh key” of normal occlusion
• Andrew’s non-orthodontic normal models had balanced tooth
size
• If not, there would have been other spacing in one arch or
crowding in the opposing arch
44
KEY VII – CORRCT TOOTH SIZE BOLTON’S
RATIO
Maurya R, Gupta A, Garg J, Mishra HA. Seventh key of occlusion: Diagnostic signifi cance in
different angle’s class I, II and III malocclusions. J Orthod Res 2015;3:188-91

45. 45
CONCLUSION

46. • Textbook of Contemporary Orthodontics by William R. Proffit - 6th edition
• Management of Temporomandibular Disorders and Occlusion – 8th edition by
Jeffrey P. Okeson
• Textbook of Occlusion by Hamish Thomson - 1975
• Textbook of Fundamentals of Occlusion by Jonathan P. Wiens - 2015
• Textbook of Prosthodontics by V. Rangrajan, T.V. Padmanabhan – 2013
• A Detailed Consideration of the Line of Occlusion, Robert M Ricketts, The Angle
Orthod,1978,48(4),274-281
• A discussion of Begg’s attritional occlusion model as correct occlusion,
Aug.Orthod.J. 11(3)March 1990 :190-194
• Andrews LF. The six keys to normal occlusion. Am J Orthod 1972;63:296-302.
• Equilibrium theory revisited : factors influencing position of teeth- William R.
Proffit
• The curve of spee - revisited Am J Orthod Dentofac Orthop (1996;110:206-10.)
• Maurya R, Gupta A, Garg J, Mishra HA. Seventh key of occlusion: Diagnostic
significance in different angle’s class I, II and III malocclusions. J Orthod Res
2015;3:188-91
46
REFERENCES

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