This document discusses the adaptive capacity of the periodontium to occlusal forces. It describes how the magnitude, direction, duration, and frequency of occlusal forces can impact the periodontium. Forces beyond the tissues' adaptive capacity can cause injury, referred to as traumatic occlusal force or trauma from occlusion. The document outlines the tissue response stages to increased forces, including injury, repair, and adaptive remodeling. It also discusses the interaction between traumatic occlusal forces and inflammation.

1. PERIO-OCCLUSION
RELATION SHIP

2. ADAPTIVE CAPACITY OF THE
PERIODONTIUM TO OCCLUSAL FORCES
▪ The PDL are arranged to accommodate the F. exerted on the crown.
▪ When occ. F. exceeds the adaptive capacity of PD tissues INJURY
▪ The effect of occ. F. on the periodontium is influenced by the magnitude,
direction, duration, and frequency of the forces.
1- the magnitude of occ. F widening of PDL space & ↑ thickness of
PDL fibers & change in density of alveolar Bone.

3. 2- Direction of forces
Occ. F. along the long axis of the tooth=well tolerated
so
Lateral (horizontal) and torque (rotational) forces
cause injury to the periodontium.
3- Duration and frequency of occ F……affect alveolar Bone
▪ Constant F >>injurious >>intermittent F
&
▪ More frequent>>>> more injurious
▪ The max. forces on an adult molar= 0.4-1.8 grams.

4. TYPES OF OCCLUSAL FORCES
▪ Physiologically normal occ. Forces
in chewing and swallowing.
Provide the +ve stimulus to maintain the periodontium & the alveolar bone in a healthy
condition.
▪ Impact forces:
mainly high but of short duration.
The periodontium can sustain high forces for a short period.
▪ Continuous forces:
▪ very low forces (for ex: orthodontic forces)
▪ Continuous forces in one direction are effective in displacing a tooth by remodeling the
alveolus.
▪ Jiggling forces:
▪ Intermittent forces in two different directions (for ex: premature contacts crowns,
fillings)
▪ Cause widening of the alveolus………… increased mobility

5. ▪ When occ. F. exceed the adaptive capacity of the tissues tissue injury.
▪ This injury is also termed” traumatism” or “occlusal trauma”.
▪ SO TFO refers to the Tissue injury NOT the occ. force
▪ Excessive occ. F. disrupt the function of the masticatory muscles ( pain &
spasms)+ injure the TMJ , or produce excessive tooth wear.
Trauma from occlusion
1)TFO alone( absence of infl.)
 doesn’t initiate G. infl. OR cause PD pocket OR  GF.
  mobility, widened PDL, loss of crestal bone height and volume, but NO
CAL.
2)TFO + infl.
angular bone loss + intrabony pocket
Rx mobility &  bone density BUT NO CHANGE in attachment OR bone level.

6. Classification of TFO
Based on causative factors
Primary TFO
Secondary TFO
Based on duration
 Acute TFO
 Chronic TFO

7. Acute TFO Chronic TFO
Less common More common
Causes Result from abrupt change in occ. F. Result from gradual changes in occlusion
Examples Biting hard objects
High restoration/appliance
Parafuctional habits
Sequel of acute TFO
Tooth wear
Drifting /extrusion movement
Clinical features Tooth pain
Sensitivity to percussion
Mobility
Cementum tear
Thickening of lamina dura
Widening of PDL space
Angular bone loss
Tooth mobility
Management
&
complications
-Remove cause??…..healing
-If not ……abscess-necrosis- cemental
wear-turn to chronic TFO
-Remove the cause
-If not …..abscess-necrosis

8. ACUTE TRAUMA
CHRONIC TRAUMA

9. Primary trauma from occlusion:
▪ is caused by excessive and non-physiological forces exerted on teeth with a normal, healthy
periodontium( no CAL).
▪ It results due to change in occlusal forces.
▪ No attachment loss & don’t initiate pocket. Y?because the supracrestal G. fibers are not
affected SO there is no apical migration of the JE.
Examples
1- High filling.
2-Prosthetic replacement that create excessive forces on abutment.
3-Drifting movement or excursion of teeth.
4-Orthodontic movement

10. Secondary trauma from occlusion:
▪ It results from reduced ability of the tissues to resist the occ. F. causing damage to
periodontuim.(attachment loss present)
▪ G. inflammation + bone loss impair the adaptive capacity to withstand occ. F
previously well tolerated occ. F. become traumatic INJURY .

11. STAGES OF TISSUE RESPONSE TO INCREASED
OCCLUSAL FORCES
▪ Slightly Excessive Pressure:
..Stimulate resorption of alveolar bone.
..Widening of PDL.
.. ↓ no & size of BV
▪ Slightly Excessive Tension:
.. Elongation of PDL fibers
.. Apposition of alveolar Bone
..Blood vessels  enlarged
Stage I: Injury

12. ▪ Greater Pressure:
▪ PDL compression
▪ Fibroblasts &other C.T. cells  necrosis.
▪ Vascular change blood stasis and RBCs are packed
▪ Alveolar bone increase bone resorption
▪ Severe Tension:
Widening of PDL space ,thrombosis ,hemorrhage ,tearing of PDL & resorption of
alv. bone.
Pressure Severe Enough To Force Root Against Bone:
▪ Necrosis of PDL.
▪ Bone resorbed adjacent to necrotic areas & from marrow spaces
▪ This is called: undermining resorption.
N.B the most susceptible areas to injury  furcation areas

13. STAGE II: (REPAIR)
▪ Trauma stimulates reparative capacity
▪ Damaged tissues are removed & new C.T cells , fibers , bone & cementum are
formed .
▪ Forces remain traumatic ONLY IF destructive capacity>> the reparative capacity.”
▪ When bone is resorbed by excessive occ. forces , the body tries to reinforce the
thinned bony trabecule to form new bone ”BUTTRESSING BONE FORMATION
Buttressing Bone Formation :
A. Central within the jaw.
B. Peripheral  on the bone surface "shelf like thickening" “LIPPING "

14. STAGE III: ADAPTIVE (REMODLING OF THE PERIODONTIUM)
▪ If the repair>> CAN'T COMPENSATES >>the destruction  periodontium is
remodeled so that the forces aren’t injurious.
▪ The result for this will be:
▪ Widening PDL "funnel shape at crest"
▪ Angular defect even if ”no pockets"
▪ Tooth becomes loose
▪ Increase vascularization

15. THE INJURY PHASE Increase resorption & decrease formation
THE REPAIR PHASE  decrease resorption & increase formation
AFTER THE ADAPTIVE REMODLING  Resorption & formation return to
the normal

16. Interaction of TFO & inflammation
 Collagen -  leukocytes - osteoclasts - BV
Supragingival plaque into subgingival
(infl. Extend To PDL)
Angular bone loss & infrabony pockets
Mobility

17. Reversibility of traumatic lesions:
▪ TFO  reversible, BUT not always correct itself
▪ IF the injurious force is removed  repair occurs
▪ If TFO persists  PD damage  worsens the condition
N.B Infl. + TFO irreversible even if the cause is removed.

18. EFFECTS OF INSUFFICIENT OCCLUSAL FORCE:
▪ Thinning of PDL, atrophy of fibers
▪ Osteoporosis of alveolar bone, reduction in bone height
▪ Examples:
1. Open bite
2. Absence of functional antagonists
3. Unilateral chewing habits

19. Clinical signs of TFO:
1. Tooth mobility & +ve fremitus due to :
▪ Destruction of PD fibers
▪ Advanced bone loss
▪ Inflammation of PD pocket
2. Tooth facets (occlusal wears) & chipped or fractured tooth
3. Pain on percussion & hypersensitivity

20. Radiographic signs of TFO:
▪ Increase width of PD space
▪ Thickening of lamina dura (lateral and apical)
▪ Vertical rather than horizontal destruction of ID
septum(funnel shaped bone loss)
▪ Radiolucency and condensation of alveolar bone
▪ Root resorption

21. PATHOLOGIC TOOTH MIGRATION
Tooth displacement ??that results when disturbing the factors that
maintain physiologic tooth position by PD disease.
▪ It is relatively common(esp. in ant. Teeth)
▪ May be an early sign of PD disease, Or ass. with G. infl. and pocket
formation.

22. FACTORS causes PATHOLOGIC MIGRATION
▪ Weakened Periodontal Support????
▪ Changes in the Forces Exerted on the Teeth:
Un-replaced Missing Teeth
Pressure of tongue(no PD disease)
Periodontal destruction (P. from granulation tissues )BUT after
pocket removal : tooth may return

23. Results of Un-replacing Missing 1st molars:
▪ The 2nd& 3rd molars tilt mesially decrease in vertical dimension.
▪ The premolars move distally, and the mandibular incisors tilt or
drift lingually. The premolars lose their intercuspating relationship
▪ Diastema & separation of the anterior Teeth.
▪ The max. incisors are pushed labially and laterally. Anterior
overbite is increased. The mandibular incisors strike the
maxillary incisors near the gingiva or traumatize the gingiva.