traumatic occ forces Flashcards
Occlusal Trauma (OT) Diagnosis
Injury resulting in tissue changes within the attachment
apparatus (periodontal ligament, cementum and supporting bone) as a result of occlusal forces (etiology)
OT may occur in what periodontiums?
normal or reduced
What is a ‘reduced’ periodontium?
Based on an in vitro study, reduced is loss of >60% of bone support.
Occlusal Trauma (OT) does not cause:
pocket formation or lead to loss of connective tissue
Parts of the Periodontium Affected by Occlusal Forces
- Cementum
- PDL
- Alveolar Bone Proper
The gingiva and junctional epithelium are not
affected by occlusal forces.
classes of traumatic occ
primary, secondary and ortho related
Occlusal Trauma Variables:
- Direction of force.
- Magnitude of force.
- Duration of force.
- Frequency of occurrence.
Trauma From Occlusion
1. Considered to be?
2. Forces of occlusion exceed the?
- Considered to be pathologic.
- Forces of occlusion exceed the adaptive capacity
of the periodontium
pathological vs physiological changes to perio
Primary Occlusal Trauma 2017
Traumatic occlusal forces applied to a tooth or teeth with normal periodontal support
* With Primary occlusal trauma, clinically may see adaptive mobility (does not progress)
* Example is ‘high’ restoration with mobility resolving following reduction.
Secondary Occlusal Trauma 2017
Injury resulting in tissue changes from normal or
traumatic occlusal forces applied to a tooth or teeth
with reduced periodontal support
* May be seen as progressive mobility &/or pain
centers for rotation in primary vs secondary OT
lower in secondary with reduced perio
Trauma from Occlusion
A. Compression side
* PDL space?
* fiber orientation?
* capillary permeability? result?
* alveolar bone proper? (if severe?) PDL space?
- PDL space is reduced as fibers are compressed
- Loss of fiber orientation
- Increased capillary permeability, rupture of blood
vessels and hemorrhage into PDL perivascular
spaces (edema) - Resorption of alveolar bone proper (root resorption
if severe) then widening of PDL space
Minor Trauma (from occlusion)
* capillary permeability?
* edema?
* Vascular damage?
* Lowered periodontal resistance?
* Accompanying tissue effects?
- Increased capillary permeability, dilation
- Edema, disturbed fluid exchange
- Vascular damage with stasis, clotting, thrombosis
- Lowered periodontal resistance?
- Accompanying tissue effects, usually mino
Trauma from Occlusion
B. Tension side
* PDL space?
* PDL fiber bundles?
* PDL blood vessels and hemorrhage into perivascular spaces?
* alveolar bone? PDL space? (If severe?)
Trauma from Occlusion
B. Tension side
* Increase in PDL space
* Rupture of PDL fiber bundles
* Compression of PDL blood vessels and
hemorrhage into perivascular spaces
* Deposition of new alveolar bone and decrease in
PDL space (If severe, cemental tears)
Severe Trauma (from occlusion)
* type of injury? - necrosis?
* results?
- Crushing (pressure) injury - necrosis at furca, alveolar crest
- Extravasated RBCs, hematoma, necrosis, vascular damag
Severe Trauma (from occlusion)
* necrosis? where?
* Degenerative changes?
* Repair from?
- Well-defined necrosis: PDL, cementum, bone
- Degenerative changes (hyaline, mucoid, liquefaction)
- Repair from PDL, endosteal cells, bone marrow, Haversian systems (rear resorption)
The lesion of Occlusal Trauma can only be confirmed how? so we must use?
The lesion of Occlusal Trauma can only be confirmed
histologically by block section biopsy, so must use
other surrogate indicators:
* Clinical
* Radiographic
Proposed clinical and radiographic indicators of occlusal trauma
Fremitus
A palpable or visible movement of a tooth when
subjected to occlusal forces
Clinical Signs/Symptoms of Occlusal Trauma
1. Mobility?
2. Radiographic evidence of?
3. Positive Hx of?
4. Missing or tilted teeth?
5. Evidence of what occ interferences?
- Mobility of affected teeth.*
- Radiographic evidence of thickened PDL.
- Positive Hx of clenching or bruxism.
- Missing or tilted teeth.
- Evidence of working and/or balancing side occlusal interferences
mobility index
1 = first distinguishable sign of movement > than normal (physiologic)
2 = movement which allows crown to move 1 mm from its normal position in any direction
3 = tooth may be rotated or depressed in alveoli
Must use 2 rigid instruments, NOT fingers
Occlusal Discrepancies
- Working &/or balancing interferences:
1. * Evidence of occlusal slide in CR or CO
1. * Evidence of occlusal interferences in protrusive
mandibular movement
1. * Extremely steep cuspal inclines - Wear facets (BUT may be normal part of aging)
Bruxism
Grinding, clenching or clamping of the teeth.
* The force may damage tooth or attachment apparatus
Signs & symptoms of bruxism:
* mobility?
* Pulpal? bite?
* occ wear?
* percussion sound?
* Muscles?
* TMJ?
* Audible?
- Increased mobility
- Pulpal sensitivity / bite tenderness
- Non-masticatory / excessive occlusal wear
- Dull percussion sound
- Muscle tenderness / spasm / hypertrophy / tiredness (am)
- TMJ pain / jawlock
- Audible sounds
Other Manifestations of Traumatic
Occlusal Force
- Malocclusions
- Tooth migration
- Fractured teeth
Radiographic Signs of occ interferences
- Widened PDL space
- Thickening of lamina dura
- Vertical (angular) bone loss
- Furcal bone loss
- Alveolar radiolucency &/or condensation
Periodontal Ligament Dimensions
- PDL thickest at apices & alveolar crest (0.20mm);
Less at mid-root (0.15 mm) - Varies with functional / force status of tooth
PDL widening
can be due to OT, occur at any location of PDL
Problems with surrogate indicators
* Existing loss of?
* Wear facets may be due?
* Altered vitality of teeth?
- Existing loss of attachment may contribute to
mobility - Wear facets may be due to ‘normal’ function rather
than parafunctional habits (bruxism, clenching,
grinding) - Altered vitality of teeth may be due to other factor
Indications for Occlusal Adjustment
- Traumatic injuries / soft tissue injury; food impaction
- Increasing mobility or fremitus
- Parafunctional habits
- In conjunction with orthodontic/ orthognathic therapy
Contraindications to Occlusal Adjustment:
Absence of a?
* treatment for periodontal disease?
* As primary therapy of?
* tooth position?
* perio inflam?
Absence of a pre-treatment diagnosis
* As prophylactic therapy or only treatment for periodontal disease
* As primary therapy of bruxism
* Severe extrusion or malpositioned teeth
* When periodontal inflammation has not been controlled
Effect of Periodontal Treatment on Mobility
Tooth mobility negatively affects outcome of periodontal therapy and maintenance
Tooth mobility generally will decrease once inflammation is controlled
‘Recommendations’ from Workshop on occ adjustment
* If see signs and symptoms of occlusal trauma and patient’s comfort and function are impacted then perform?
* Evaluate and record occlusion when?
* Treatment of occlusal trauma ‘may slow the progression of? an improve?
- If see signs and symptoms of occlusal trauma and patient’s comfort and function are impacted then perform occlusal adjustment in conjunction with periodontal therapy
- Evaluate and record occlusion before, during and after treatment
- Treatment of occlusal trauma ‘may slow the progression of periodontitis and improve the prognosis’
can teeth with reduced periodontium undergo ortho tx
teeth with a reduced but healthy periodontium (no inflammation) may undergo successful tooth movement without compromising periodontal suppor
Occlusal Hyperfunction
- Slight increase in occlusal force.
- Considered to be a physiologic adaptation
and not a pathologic entity.
Clinical Symptoms of Occlusal Hyperfunction
1. collagen fiber bundles in PDL?
2. width of PDL?
3. alveolar bone proper (lamina dura)?
4. Radiographic evidence of?
5. tooth mobility?
- Increase in number and diameter of collagen
fiber bundles in PDL - Increased width of PDL.
- Increased density and thickness of alveolar
bone proper (lamina dura). - Radiographic evidence of osteosclerosis.
- Slight or undetectable tooth mobility
Occlusal Hypofunction
1. defined?
2. Considered to be?
3. Can only be diagnosed by?
- A mild weakening of the tooth supporting
structures due to lack of physiologic
stimulation. - Considered to be a physiologic adaptation
and not a pathologic entity. - Can only be diagnosed by histology.
Occlusal Hypofunction
1. number of PDL fiber bundles? orientation?
2. physiologic turnover and remodeling of alveolar bone?
3. PDL space?
4. tooth mobility?
- Decrease in number of PDL fiber bundles but normal orientation.
- Decreased physiologic turnover and remodeling of alveolar bone.
- Narrowing of PDL space.
- No change in tooth mobility
Disuse Atrophy
Total removal of occlusal forces resulting in lack of the level of physiologic stimulation required to maintain
normal form and function.
Physiologic adaptation and not considered pathologic.
Clinical Symptoms of Disuse Atrophy
1. PDL?
2. tooth mobility?
3. Absence of?
- Radiographic evidence of decreased width
of PDL space. - Increased tooth mobility is always present.
- Absence of occlusal antagonist.
Disuse Atrophy
1. principle fibers?
2. PDL?
3. effects on bone?
- Loss of orientation of the principle fiber bundles of the PDL.
- Narrowed PDL width.
- Significant decrease in number of bony trabeculae, i.e., localized osteoporosis
Trauma from occlusion, in the absence of
inflammation, does not cause:
- gingivitis
- periodontitis
- pocket formation
recomendations for implant occ
- Recommendations still lacking regarding implant
occlusion but include: - Mutually protected occlusion with:
- Anterior guidance
- Wide freedom in centric relation (decrease cuspal
inclines) - Reduce occlusal overload (more implants, less
cantilevers) - Close monitoring for parafunctional habits
occ adjustments and bite guards for implants
- Occlusal adjustment (prior to implant restoration)
- Hard acrylic bite guard in all cases (or where parafaunctional habits are suspected)
Conclusions for Traumatic Occlusal Forces (TOF)
* evidence that this causes periodontal attachment loss in humans?
* evidence (animal and human) that it causes inflammation in the periodontal ligament?
* Observational studies that TOF may be
associated with severity of?
* Animal model- may increase? Human?
- No evidence that this causes periodontal
attachment loss in humans - Limited evidence (animal and human) that it
causes inflammation in the periodontal ligament - Observational studies that TOF may be
associated with severity of periodontitis - Animal model- may increase alveolar bone loss
- Human- no evidence
Traumatic Occlusal Force(s) and
Abfraction
NO EVIDENCE that TOF causes non-carious cervical
lesions (NCCLs). Most studies used finite element
analysis (not clinical)
NCCLs may result from abrasion, erosion or corrosion
Recession and traumatic occ
EVIDENCE from observational studies that Traumatic
Occlusal Force does NOT cause gingival recession
Abfraction
evidence to support existence of abfraction?
Therefore?
No credible clinical evidence to support existence of
abfraction
Therefore there can be no evidence implicating
abfraction as cause of recession
