occlusion -dental

2. DR JISNA
PG 1 ST Year

3. -Introduction:
Definition
Importance of normal occlusion
-Basics of occlusion: Centric occlusion
Centric relation
Eccentric occlusion
-Anterior -Posterior inter-arch relationship.
-Inter-arch tooth relation ship.
-Posterior cusp characteristics.
-Compensatory curves.
-consequences of abnormal occlusion.
-Role of occlusion in smile design.
-Important considerations while choosing restorative material as regards
to occlusion.
-Occlusion considerations in restoring individual teeth.
-Conclussion.

4. Occlusion is one of the most important concepts in
dentistry. The success of many dental treatments relies
headily on a stable & harmonious occlusion.
All teeth have specific contours, which help to deflect the
food away from gingival margins during mastication &also
affect the transmission of occlusal forces.
Occlusion = contact between teeth
(British dental journal 191,08 sep 2001)

5. DEFINITION OF OCCLUSION-
The contact of teeth in opposing dental arches ,when jaws
are closed (static) and during various jaw movements
(dynamic).
(sturdavent’s)
The word “occlusion” comes from the latin expression
occludere which means “ to close”.
IMPORTANCE OF NORMAL OCCLUSION- Mastication
-Speech
-Appearance
-Stability

7. BASICS OF OCCLUSION
. Centric occlusion
. Centric relation
. Eccentric occlusion 1)Functional occlusion
-lateral functional occlusion
(a)canine guided occlusion
(b)group lateral occlusion
-protrusive functional occlusion
2)non functional occlusion
-lateral non functional occlusion
-protrusive non functional
occlusion

8. CENTRIC OCCLUSION-
The occlusion of opposing teeth when the mandible is
in centric relation, this may or may not coincide with the
maximum intercuspal position (gpt8).
It is tooth to tooth contact

10. CENTRIC RELATION
 This is a jaw relationship
Anatomically-most posterior position of condyle in glenoid
fossa.
Conceptually-position of mandible relative to maxilla with
articular disc in place when the muscles are in most relaxed
and least strained position.(sturdevant’s)
 It is actually not a mandibular position but an axis around
which mandible can rotate.
 Clinically it can identifiable ,recordable, reproduceable.
(journal of the Irish dental association Aug 2015 vol 61)

12. FUNCTION OF CENTRIC RELATION-
1) It is learnable, repeatable, recordable position
2) it is a reference point
3) is a starting point for developing the occlusion.
4)dependable jaw relation boz it is bone to bone relation
5) helps in functional movements
 0(

13. RELATIONSHIP BETWEEN CENTRIC RELATION AND CENTRIC OCCLUSION
 Centric occlusion also termed as inter cuspal contact position upon
closure of mandible in centric relation, the mandible slides forward
to a position where the maxillary and mandibular teeth intercuspate
maximum in centric occlusion.
 CR is bone to bone relation where CO is tooth to tooth contact
 CO doesnot coincide with the CR in most of the people with natural
teeth
 If CO coincides with CR they apper to be the same

14. ECCENTRIC OCCLUSION-
 Contact of teeth that occurs during movements of mandible
1) FUNCTIONAL OCCLUSION OR PHYSIOLOGIC OCCLUSION- Occlusion which
efficiently function without any pain or pathology irrespective of the
relationship b/w maxilla and mandible .
Aim- freedom from disease In all masticatory system structures
-maintain healthy periodontium
-stable TMJs
-maintaining healthy teeth
-optimum esthetics.

15.  LATERAL FUNCTIONAL OCCLUSION- it includes tooth contacts that occurs
on canine and posterior teeth on the side towards which
mandible moves.
 A)CANINE GUIDED OCCLUSION-During lateral mandibular
movements ,the opposing upper &lower canines of the working
side contact thereby causing dis-clusion of all posterior teeth on
working & balancing side
Seen in young individuals with unworn dentition
 B)GROUPED LATERAL OCCLUSION- in addition to canine
guidance ,certain other posterior teeth on working side also
contact during lateral movement of mandible

16. .

17. PROTRUSIVE FUNCTIONAL OCCLUSION-
Eccentric contacts that occurs when the mandible
moves forward & downward along the incline of
articular eminence.
Occurs while incising and grasping food
Occurs after the condyle rotates about in the TMJ.

19. 2)NON-functional OCCLUSION- LATERAL NON FUNCTIONAL OCCLUSION-
The contact occurs on opposing inclines between the two
zones of centric contact.
-Lingual inclines of mandibular facial cusps
-Facial inclines of maxillary palatal cusps
PROTRUSIVE NON FUNCTIONAL OCCLUSION
-The contact may occur on either or both the right and left
posterior segments.

20. 3)BALANCED OCCLUSION-
 Is the bilateral, simultaneous anterior and posterior
occlusal contact of teeth in centric and eccentric
position
Seen in complete dentures ,although it may be found in
natural dentition with advanced attrition
For complete dentures ,tooth contacts on non working
side is desirable to prevent tipping of dentures during
working movements.

21. Working side :
 Side of the jaw where bolus is placed
 The side of mandible towards which it is moving
Non working side:
 Opposite to the working side
 Avoidance of contact on the nonworking side is important for
restorative procedures.

23. The complete intercuspation of the teeth, independent
of condyle position

24.  CLASS1- Most common
 MB cusp of maxillary 1st molar occludes with MB groove of
Mandibular 1st molar.
 CLASS 2- MB cusp of maxillary 1st molar is located in facial
embrasure b/w mandibular 1st molar &mandibular 2nd
premolar
SUBDIVISION OF CLASS 2-
CLASS2 DIV 1- Max incisor teeth are in labioversion
CLASS2 DIV 2- Max incisor teeth are in linguoversion
 CLASS 3-MB cusp of maxillary 1st molar fits into the DF
groove of Mandibular 1st molar

27.  OVERJET- horizontal distance between labial surface of
mandibular anterior and lingual surface of maxillary anterior
surface.
 OVERBITE- Vertical distance between incisal edges of
maxillary anteriors and incisal edges of mandibular
anteriors.
 CLINICAL SIGNIFIANCE-influence of mandibular
movements which influence cusp design of restoration of
posterior teeth

28.  In normal Class I occlusion, the mandibular facial cusp contacts the
maxillary premolar mesial marginal ridge and the maxillary premolar
lingual cusp contacts the mandibular distal marginal ridge. Because
only one antagonist is contacted, this is termed a tooth-to-tooth
relationship.
 The most stable relationship results from the contact of the
supporting cusp tips against the two marginal ridges, termed a tooth-
to-two-tooth contact.
 In Class II occlusion, each supporting cusp tip will occlude in a stable
relationship with the opposing mesial or distal fossa; this relationship
is a cusp fossa contact.

30. Supporting cusps:
Cusps that contact the opposing teeth along the central
fossa occlusal line are termed supporting cusps (centric,
holding, or stamp cusps);
Lingual occlusal line of maxillary teeth
Facial occlusal line of mandibular teeth

31. Contact opposing tooth in MI
Support vertical dimension
Nearer facio-lingual center of tooth than non-supporting
cusps
Outer incline has potential for contact
More rounded than non-supporting cusps

33. During fabrication of restorations it is important that
supporting cusps are not contacting the opposing teeth in
a manner that results in lateral deflection of teeth. Rather,
the restoration should provide contacts on plateaus or
smoothly concave fossae so that masticatory forces are
directed approximately parallel to the long axis of the
teeth. [Sturdevant’s]

34. The cusps that overlap the opposing teeth are termed non
supporting cusps (non-centric or non-holding cusps).
Lingual occlusal line in the mandibular arch.
Facial occlusal line in the maxillary arch.

35. Do not contact opposing tooth in MI
Keep soft tissue of tongue or cheek off occlusal table
Farther from facio-lingual center of tooth than supporting
cusps
Outer inclines has no potential for contact
Have sharper cusp ridges than supporting cusps

37.  The curvature which begins at the tip of canines & followed by
buccal cusp tips of premolar & molars posteriorly when viewed
from their facial aspect
 The curve of Spee provides the professional with the greatest
possibilities of alterations.
 The greater the curvature, the higher the cusps will have to be in
order to produce efficient mastication.
 Less the curvature, the professional has to decrease the height of
the cusps so that interfering contacts may be avoided.

39.  This is a curve that contacts the buccal & lingual cusp tips of the
mandibular teeth .
 The curve of Wilson is medio lateral on each side of the arch.
 In oral rehabilitation procedures, one must take care to obey this
spatial orientation of the teeth to avoid unwanted interferences,
especially on the balancing side.
 The curve helps in two ways-
Teeth aligned parallel to the direction of medial pterygoid for
optimum resistance to masticatory forces.
The elevated buccal cusps prevent food from going past the
occlusal table.

41. MANSON(1920), connected the curve of spee and curve
of wilson to all cusps and incisal edges, and suggested
that the mandibular arch adopted itself to the curved
segment of a sphere of a 4 inch radius.

43. If left untreated it can induce a variety of issues including-
Loosening of teeth
Tooth chips, cracks, fractures
Tooth restoration damage
Recession of the gumline
Teeth clenching and gumline
Headaches
Jaw pain

44.  compressive strength: forces of mastication are compressive, so
restorative
material & tooth should have adequate resistance to avoid fracture.
 tensile strength: restoration should be planned to direct the forces
along the long axis of tooth.
 fatigue strength: is the stress at which the material fails under
repeated loading.
 wear resistance: should wear at the same rate as the adjacent
enamel.

45. - Optimal smile design should integrate facial balance and
harmony with natural form , fit and function of teeth and jaws.
- The key to evaluate the smile is the 3 dimensional position of
maxillary central incisor.
THE BIOLOGICAL MODEL
-Concept of natural tooth form ,fit &mandibular function
observed & reported by Dr Bob Lee.
-Provides for class 1 dental fit & skeletal pattern & a relatively
flat plane of occlusion
-Provides for an interference free, canine guided lateral chew&
central incisor guidance for speaking, swallowing & smiling.

47.  Provides for mandibular movement 3mm left, right or forward from
complete occlusion so that the posterior 2nd molars separate 2-3
mm due to anterior tooth contact. this pattern of movement
provides for optimal space to swallow ,chew bite, speak & smile.
POSITION 1- COMPLETE OCCLUSION (TEETH TOGETHER)
Having sufficient overjet &overbite allows lateral canine guidance
chewing without anterior incisal edge
 Biological model requires the following of occluded anterior teeth
 central incisor: Overlap vertically(overbite) 3-5 mm
Horizontally (overjet) 2-4 mm
Cuspals overlap vertically 4-6 mm
Horizontally 0.5-1mm

50. POSITION 2:this position demostrates the patient’s ability
or inability to separate all posterior teeth when the edges
of the incisors are in contact.
POSITION 3&4- The patient is instructed to move the
mandible left & right from complete occlusion while
keeping the teeth together .there should be no contact
across any incisal edges & there must be complete
separation of all posterior teeth.

52. Normal anatomical form of teeth should be restored.
Correct relationship with adjacent teeth to give the best
support against masticatory stresses.
Restore the buccolingual contour to allow deflection of
food over free gingiva.
Form should be such that oral hygiene can be maintained
Correct relationship with the opposing teeth will prevent
deflective occlusal contact ,pain and fracture of teeth

53.  There should be no contact at the early stage of centric relation.
 At centric occlusion ,the holdings cusps should be of sufficient
height to be in positive contact with their opposing counterparts.
 At centric occlusion ,the holding markings should be symmetrical
in magnitude and extent on all holding cuspal elements of both
sides.
 When maximum intercuspation is achieved there should not be
any further movement of the mandible.
 Holding cusps occluding with more than one tooth or eccentrically
occluding with opposing teeth should not move opposing teeth in a
non axial direction.
 In lateral extrusion of mandible ,there should not be any tooth
contact on the non working side of mandible.
 During protrusive excursions of mandible there should not be any
contact posteriorly

54.  Mal positioned opposing supporting cusp and ridges should
be recontoured
 establish stable centric contact
 If restoring teeth with amalgam sufficient bulk is mandatory
 Adequate thickness should be provided at marginal ridges
 Carving should follow cuspal inclines

55. The height of marginal ridge should be same as
adjacent tooth.
In case of larger restoration buccal and lingual cusp tip
should be in line with adjacent teeth
Bucco lingual width of occlusal table is kept narrower
If more than two cusp restored the occlusal table is kept
narrower
Checking of restoration done in CR,CO & excursive
movements

56. Occlusal contacts located on cuspal incline or ridge
slopes are undesirable because they cause a
defelective force on the tooth and should be adjusted
until resulting contact is stable.
Avoid over carving resulting in infraocclusion especially
in centric holding contacts.

57.  Composite &GIC mainly used.
 the restoration should be carved and finished maintaining
contacts and
cervical curvature.
 Lingual area carved to maintain the anatomy of cingulum
&marginal
ridges.
 Relationship of teeth with lips are checked, over contouring if
any should be removed.

58. ROLE OF CONTACT AREAS:
 Preserves the stability and integrity of the arch by maintaing
normal mesiodistal relation of teeth.
 Prevent food impaction
 Protect soft tissues from periodontal disesas.
ROLE OF CONTOURS:
 Facial & lingual convexities: afford protection and stimulation to
supporting structures during mastication
 Facial & lingual concavities: determine the pathways for teeth and
out of centric occlusion
 Proximal contours adjacent to contact areas: i.e embrasures –
pathways for the passage of food
ROLE OF MARGINAL RIDGES : withstanding & dissipating the
occlusal stresses

59. In its simplest of definition ,occlusion is the way the
maxillary and mandibular teeth articulate ,but in reality
dental occlusion is a much more complex relationship,
because it not only involves the study of the teeth, but
also their morphology and angulations and functional
movements
Though it is quite difficult and time consuming procedure
yet the advantage of establishing functional occlusion in
restorative warrant all clinicians to spend time and utilize
expertise on occlusal principles.

60. thankyou