This document discusses the effects of external forces on the periodontium. It states that the magnitude, direction, duration and frequency of occlusal forces influence the periodontal response. Increased forces can cause thickening of the periodontal ligament and bone, while changes in direction may cause injury. Constant pressure is more injurious than intermittent forces. Trauma from occlusion refers to tissue injury caused when forces exceed the tissues' adaptive capacity. Primary trauma results from direct changes to occlusion, while secondary trauma occurs when adaptive capacity is reduced by bone loss.

2. PERIODONTAL RESPONSE
TO
EXTERNAL FORCES
Presented by
Dr. Devarathanama M.V
MDS Sr. Lecturer

3. INTRODUCTION
The effect of occlusal forces on the periodontium
is influenced by
MAGNITUDE
DIRECTION
DURATION
FREQUENCY

4. MAGNITUDE is increased
thickening of the periodontal ligament
increase in the number and width of the
periodontal ligament fibers
increase in the density of Al.bone

5. changing the DIRECTION causes
Re-orientation of stresses and strains within
the periodontium
Lateral [horizontal] forces and torque[rotational]
forces are more likely to injure the periodontium

6. DURATION AND FREQUENCY
Constant pressure on the bone is more injurious
than intermittent forces

8. DEFINITION
When the occlusal forces exceed the
adaptive capacity of the tissues, tissue injury
results which is termed as
“ TRAUMA FROM OCCLUSION”

9. Trauma from occlusion refers to the
TISSUE INJURY, NOT THE OCCLUSAL FORCE
An occlusion that produces such injury is
“TRAUMATIC OCCLUSION”

10. ACUTE
CHRONIC

11. ACUTE
ABRUPT CHANGE IN OCCLUSAL FORCE
such as biting on a
HARD OBJECT
RESTORATIONS or PROSTHETIC APPLIANCES
that interfere with direction of occlusal forces
resulting in TOOTH PAIN
SENSITIVITY TO PERCUSSION
INCREASED TOOTH MOBILITY

12. CHRONIC
MORE COMMON
develops from gradual changes in occlusion
produced by :
TOOTH WEAR
DRIFTING MOVEMENT
EXTRUSION OF TEETH combined with
parafunctional habits such as BRUXISM and
CLENCHING

13. “MALOCCLUSION IS NOT NECESSARY TO PRODUCE TRAUMA”
Periodontal injury may occur when the occlusion
appears normal
The dentition may be anatomically and
esthetically acceptable but functionally injurious
Such traumatic occlusal relationships are referred as:
OCCLUSAL DISHARMONY
FUNCTIONAL IMBALANCE
OCCLUSAL DYSTROPHY

14. PRIMARY
SECONDARY

15. PRIMARY
result of
alterations in occlusal forces

16. insertion of a “high filling”
prosthetic replacement that creates excessive
forces on abutment and antagonist teeth
drifting movement or extrusion of teeth into
spaces created by unreplaced missing teeth
orthodontic movement of teeth into
functionally unacceptable positions

17. SECONDARY
When the adaptive capacity of the tissues to
withstand occlusal forces is impaired by bone loss

18. Tissue response to increased occlusal forces
occurs in 3 stages:
INJURY
REPAIR
ADAPTIVE REMODELLING

19. STAGE I : INJURY
SLIGHTLY EXCESSIVE PRESSURE stimulates
resorption of Al.bone, with resultant widening
of the pdl space
blood vessels are numerous and reduced in size
SLIGHTLY EXCESSIVE TENSION causes
elongation of the pdl fibers
formation of Al.bone
blood vessels are enlarged

20. GREATER PRESSURE produces a series of changes
in the periodontal ligament
within 30 mnts
- retardation and stasis of blood flow occurs
at 2-3hrs
- blood vessels are packed with erythrocytes, which
start to fragment
within 7 days
- disintegration of blood vessels and release of
contents into the surrounding tissue

21. SEVERE TENSION causes :
widening of pdl
thrombosis
hemorrhage
tearing of pdl
resorption of Al. bone
The areas of periodontium most susceptable
to injury from excessive occlusal forces are the
“furcations”

22. Pressure severe enough to force the root
against bone causes necrosis of pdl and bone
The bone is resorbed from viable pdl adjacent
to necrotic areas and from marrow spaces,
a process called “undermining resorption”

23. STAGE II: REPAIR
Repair is constantly occurring in periodontium
When bone is resorbed by excessive occlusal
forces, the body attempts to reinforce the thinned
bony trabeculae with new bone
This attempt to compensate for lost bone
is called “buttressing bone formation”

24. BUTTRESSING BONE FORMATION
occurs
within the jaw -- CENTRAL BUTTRESSING
on the bone surface - PERIPHERAL BUTTRESSING

25. STAGE III: ADAPTIVE REMODELING
When the repair process cannot keep pace
with the destruction caused by the occlusion,
the periodontium is remodeled by which the
forces are no longer injurious to the tissues
This results in:
thickened pdl
angular defects
mobility of teeth
After adaptive remodeling of the periodontium,
resorption and formation return to normal

26. INFLUENCE OF TRAUMA FROM OCCLUSION
ON
PROGRESSION OF MARGINAL PERIODONTITIS
The local irritants that initiate gingivitis and
periodontal pockets affect the marginal gingiva,
but
TFO occurs in supporting tissues and
does not affect the gingiva

27. The marginal gingiva is unaffected by TFO
because its blood supply is sufficient to maintain
even when the vessels of the pdl are obliterated
by excessive occlusal forces

28. CLINICAL SIGNS
MOST COMMON : TOOTH MOBILITY
although this tooth mobility is greater than normal mobility
IT CANNOT BE CONSIDERED PATHOLOGICAL
because
IT IS AN ADAPTATION and NOT a DISEASE PROCESS

29. RADIOLOGICAL SIGNS
WIDENING OF PDL SPACE often with thickening
of lamina dura
“VERTICAL” destruction of interdental septum
RADIOLUCENCE and CONDENSATION of Al.bone
ROOT RESORPTION

30. CONCLUSION
Trauma from occlusion
DOES NOT INTIATE
GINGIVITIS
or
PERIODONTAL POCKETS
but it may affect the progress and severity of
periodontal pockets started by local irritation

32. DEFINITION
Tooth displacement that results when the balance among
the factors that maintain physiological tooth position is
disturbed by periodontal disease

33. Occurs frequently in the ANTERIOR REGION
The teeth move in ANY DIRECTION
Accompanied by MOBILITY and ROTATION
Pathological migration in the OCCLUSAL or
LINGUAL DIRECTION is termed as “EXTRUSION”

34. PATHOGENESIS
TWO major factors play a role in maintaining the
normal position of the teeth:
1. The health and normal height of periodontium
2. The forces exerted on the teeth such as
-- the forces of occlusion
-- pressure from the lips, cheeks, and tongue

36. WEAKENED PERIODONTAL SUPPORT
The tooth with weakened support is
unable to maintain its normal position in the
arch and moves away from the opposing force
The force that moves the weakly
supported tooth may be created by factors
such as
-- occlusal contacts
-- pressure from the tongue

37. CHANGES IN THE FORCES EXERTED ON THE TEETH
these forces may occur as a result of
-- unreplaced missing teeth
-- failure to replace first molars
-- other causes

38. Forces that are acceptable to an intact periodontium
become injurious when periodontal support is reduced
Pathological migration may continue after
the tooth no longer contacts its antagonist
-- Pressure from the tongue
-- food bolus
-- granulation tissue
provide the force

39. UNREPLACED MISSING TEETH
drifting defers from pathologic migration in
that it does not result from destruction of the
periodontal tissues
drifting generally occurs in mesial direction

41. FAILURE TO REPLACE FIRST MOLARS
RESULTS IN:
i. The second and the third molars tilt, resulting
in a decrease in vertical dimension
ii. The premolars move distally, and mandibular
incisors tilt or drift lingually
iii. Anterior overbite is increased

42. iv. The maxillary incisors are pushed labially
and laterally
v. The anterior teeth extrude
vi. Diastema is created by the separation of
anterior
teeth

43. The disturbed proximal contact relationships
lead to :
-- food impaction
-- gingival inflammation
-- pocket formation
-- bone loss and
-- tooth mobility

45. OTHER CAUSES
Trauma from occlusion
Pressure from the tongue
Pressure from the granulation tissue