trauma from occlusion, etiology, types of trauma from occlusion, sign and symptomes, histologic changes and treatment

2. “ A condition where injury results to the
supporting structures of the teeth by the act
of bringing the jaws into a closed position.”
(stillman1917)
“damage in the periodontium caused by the
stress on the teeth produced directly or
indirectly by the teeth of opposing jaws”
(WHO in 1978)

3. “When occlusal forces exceed the adaptive
capacity of periodontal tissues, the tissue
injury results.This resultant injury is termed
as a trauma from occlusion.” ( a/c to Orban and Glickman)

4. There are many factors involved in the etiology
ofTFO. Broadly they can be divided into 2
categories:
1. Precipitating factor
2. Predisposing factor

5. 1. Precipitating factor
Destructive occlusion forces are the
precipitating or primary etiology of theTRO.
The occlusal forces when within the normal
range can be well adapted by tooth-
supporting soft tissues. But when these
forces exceed the adaptive capacity of the
tooth supporting tissues, pathological
changes can be seen in the soft tissue.

6. These forces are usually described in terms of
magnitude, direction, duration and
frequency.
 Magnitude( the amount)- when it is
increased the periodontium reponds
a) With thickening of the periodontal ligament,
b) An increase in the number and width of the
periodontal ligament fibres and
c) An increase in the density of the alveolar
bone

7.  Direction – the principal fibres of periodontal
ligament play an important role in
withstanding the occlusal forces and
transferring them to alveolar bone.
But , if the direction of occusal forces is
changed, these fibres are not able to
efficiently bear the forces hence injury
results.

8.  Duration – constant pressure on the bone is
the more injurious than inttermittent forces.
 Frequency - the more frequent the
application of an intermittent force, the more
injurious to the periodontium.

9. 2.Predisposing factor – these can be divided
into intrinsic and extrinsic factors.
 Intinsic factors
a. the orientation of the long axis of the teeth in
relation to forces to which they are exposed.
b. The morphological characteristics of the
roots.

10. The size , shape, and number of the roots
determine how occlusal forces are
dessipated.
In general , short ,conical, slender or fusedroots
are more vulnerable toTFO.
c.The morphology of the alveolar process, i.e.
the quality and quantity of the alveolar bone
play an important role in absorbing the
occlusal forces.

11.  Extrinsic factors
a. Local factor such as plaque which predispose
to alveolar bone loss.
b. Fabrication of long span bridges on few
teeth, thus overloading them.
c. Injudicious bone resection during surgical
periodontal therapy or oral surgical
procedure.

12. d. Parafunctional habits as a results of neurosis.
e. Other factors includes the food impaction,
overhanging filling, poorly coloured crown
and bridges, and ill fitting partial dentures.

13. 1. Depending on the onset and duration
 Acute trauma from occlusion -produced by
biting on a hard object, in addition could also
be due to iatrogenic factors(faulty
restoration/prosthetic appliance.)
 Chronic trauma from occlusion- due to tooth
wear, drifting movement, extrusion of teeth
combined with parafunctional habits such as
bruxium and clenching.

14. 2. Depending on the cause
 Primary trauma from occlusion- it is a tissue
injury, which is elicited around a tooth with
normal height of periodontium.
example- insertion of high fillings, insertion of
prosthetic replacement, orthodontic
movement in functionally unacceptable
position.

15.  Secondary trauma from occlusion - it is
related to situation in which occlusal forces
cause injury in a periodontium of reduced
height.
Example- periodontitis

16.  When evaluating a patient suspected of having
occlusal trauma there are a number of clinical
and radiographic symptoms that may be
present.These indicators of trauma from
occlusion may include one or more of the
following
Clinical
1) Mobility (progressive)
2) Pain on chewing or percussion
3) Fremitus
4) Occlusal prematurities/discrepancies

17. 5)Wear facets in the presence of other clinical
indicators
6)Tooth migration
7) Chipped or fractured tooth (teeth)
8)Thermal sensitivity
 Radiographic
1)Widened PDL space
2) Bone loss
(furcations; vertical; circumferential)
3) Root resorption

18.  The response of tissue to increased occlusal
forces is explained under 3 stages:
1) Injury
2) Repair
3) Adaptive remodeling of the periodontuim

19. When tooth is exposed to excessive occlusal
forces, the periodontal tissue to withstand
and hence they distribute, while maintaining
the stability of tooth.
When tooth is subjected to horizontal forces the
tooth rotate or tilts in the direction of force.
This tilting results in the pressure and tension
zones, within the marginal and apical parts of
periodontium.

23.  Slightly excessive force
The slightly excessive force stimulate bone
resorption in the area of the pressure, causing
the widening of periodontal ligament space.
In the area of tension , elongation of
periodontal ligament fibres takes place.The
blood vessels on the pressure side are
compressed whereas on the tension side they
are enlarged. in the due course of time, slow
remodeling of the alveolar socket takes place.

24.  Greater than slightly excessive forces
Marked change in tooth structures are seen.The
excessive compression of periodontal ligament
produces area of hyalinization. Areas of necrosis
can be seen in periodontal ligament due to
excessive trauma to the periodontal ligament
fibres and connective tissue cells including
fibroblast. Within 30 minutes of application of
such traumatic forces on the tooth, vascular
changes can be seen.

25.  severely high forces
Severely high forces results in thrombosis,
hemorrhage, tearing of the periodontal
ligament, widening of periodontal ligament
space and alveolar bone resorption.
Under severely high force, on the pressure side
, there is a disturbance of blood flow in the
compressed PDL and cell death in the
compressed area of the PDL(hyalinization).

26. The 1st sign of hyalinization is the presence of
pyknotic nuclei in the cells, followed by areas of
acellularity, or cell free zones.
Due to injury caused by occlusal trauma , there is a
temporary reduction of mitotic activity of the
cells, including fibroblast and osteoblasts. In the
presence of excessive occlusal forces, all the
above changes take place, but if the forces are
removed or tooth moves away from the forces,
the periodontium is completely restored.

27. Depending on the types of forces there can be
many histologic changes

30.  The diagnosis and assessment (flowchart) of
occlusal trauma is not merely made based on a
single examination, due to the necessarily
progressive nature of injury. Orthodontic
correction is usually restricted to cases where
tooth malpositions are the prime cause of
trauma.There are certain additional factors such
as morphology, prognosis of the teeth involved,
direction and magnitude of movement required
that will influence the decision of whether or not
orthodontic tooth movement is indicated.

34.  The treatment ofTFO involves removal of the
excessive occlusal forces and bringing the tooth/
teeth in a comfortable position. Many treatment
modalities have been adviced to treatTFO.
These include,
 Occlusal adjustment
 Management of parafunctional habits
 Splinting of teeth
 Orthodontic tooth movement
 Occlusal reconstruction
 Extraction of selected teeth