DENT 267: LO7 LS1- Occlusal Trauma (OT)

trauma from occlusion

-injury to the periodontium resulting from excessive occlusal forces

primary trauma from occlusion

-injury to a healthy periodontium resulting from excessive occlusal forces

secondary trauma from occlusion

-injury from normal or excessive occlusal forces applied to a periodontium previously damaged by periodontitis

occlusal trauma

-injury to the periodontium

-in excess of the reparative/adaptive capacity

-on a healthy tooth or on a tooth w/ perio disease

-assess client's static occlusion

-centric occlusion/centric relation

-clients w/ malocclusion may be more susceptible to occlusal trauma

-event clients w/ so called normal occlusions may experience occlusal trauma

-also want to assess the functional occlusion

-can play a role in the perio disease process

-may alter pattern of bone resorption

effects of occlusal trauma

-periodontium

-TMJ

-muscles of mastication

-pulp tissue

-integrity of restos/teeth

occlusion

-contact relationship: during chewing and swallowing

-centric occlusion

-centric relation

malocclusion

-occlusal trauma more common

functional occlusion

-working side

-balancing side

-lateral excursions, the contacts are assessed

-group function

-cuspid guided

-protrusive guidance as the mandible moves forward is thought to be ideal on anterior teeth only

-posterior contacts during protrusive excursions are thought to be undesirable

functional occlusion: occlusal prematurities/interferences

-may occur during centric, lateral and protrusive occlusion

-example: high restoration, malocclusion

physiologic occlusion

-client in comfort, no pathologic changes

-pathologic occlusion

-an occlusion that produces pathologic changes in the tissue

orthofunction

-state of harmony when forces developed during function are within a adaptive range

dysfunction

-forces of occlusion cause pathogenic changes in the tissues

-these changes result in abnormal function of pain

-degree of dysfunction can be slight or significant

-typically more common in those w/ malocclusions

morphofunctional harmony to disharmony

-when forces directed through teeth and periodontium in function and parafunction exceed what an individual system can handle, dysfunction can result

-this trauma occurs when the greatest force is exerted against a weakened periodontium

characteristics of optimal occlusal function

-absence of interferences

-bilateral distribution of forces

-axial loading

-acceptable inter-occlusal distance

-minimizing of parafunctional habits

-harmony b/w centric occlusion and centric relation

occlusal forces

-force of energy transmitted to teeth and periodontium

-when the magnitude, direction, frequency and/or duration exceeds the reparative capacity of the tissues, the result is occlusal trauma

-determined clinically by signs & symptoms

history: occlusal trauma

-occlusal probs can predispose a person to periodontal breakdown but not a causal or initiating factor (2003)

-soon after microorganisms were identified as risk factors for periodontitis, the role of occlusion was considered

does occlusal trauma cause perio disease

-no

is occlusal adjustment to prevent PDD advocated

-no bc there is no evidnce that occlusal forces initiated PDD

can occlusal adjustment of excessive occlusal forces treat existing PDD

-based on studies, yes

histology/pathogenesis of occlusal trauma

-in a health periodontium, histologically, there are no classic signs of inflammation

-no inflammatory/immune cells such as leukocytes, lymphocytes, plasma cells present (only if pre-existing perio disease)

-repair is initiated after the trauma is removed

-develops from compression and tension of PDL fibers and resorption & deposition of bone

-compression of PDL fibers results in obstruction of blood flow to the fibres which causes bone resorption

lateral occlusal forces

-tipping of the tooth within the socket due to lateral occlusal forces

-area of pressure

-area of tension

pathogenesis of occlusal trauma

-bone resorption areas of pressure which results in widening of the PDL space

-increased mobility

-as the PDL adapts, new lamina dura may become visible on the radiograph

-when the occlusal trauma is eliminated, bone repair will occur & the functional width of the PDL will be re-established

-the gingival CT is not affected nor is there apical migration of the PDL

aspects of occlusal forces

-magnitude

-axial loading

-lateral forces

-torque or rotational

-duration/frequency

axial loading

-ideally would like occlusal forces directed along the long axis of teeth

-anti-axial forces (lateral forces) can be detrimental and cause pressure and tension on PDL fibers

anti-axial/lateral forces/rotational forces

-axial forces directed along the teeth & periodontium usually meet the demands necessary for normal function

-parafunctional activity (grinding or clenching) often leads to anti-axial forces

increases in magnitude

-increase in number and width of PDL fibers

-increase in bone density

-compression of apical area

-tension in other areas

duration/frequency

-constant forces recurring overtime can cause resorption (clenching)

-intermittent forces can cause bone formation (bruxism)

classification of occlusal trauma

-primary

-secondary

primary occlusal trauma

-heavy/abnormal occlusal forces exceed the adaptive range in a normal periodontium causing injury to tissues and bone

-no evidence of attachment loss due to periodontitis

-changes seen include wider PDL space, mobility and pain

-reversible if trauma is removed

examples of causes of primary occlusal trauma

-high restorations or prostheses

-centric prematurities/balancing side contacts

-poor designed restos or prostheses that generate tipping occlusal forces

-tipping/drifting of teeth

-misaligned teeth (malocclusion)

-parafunctional habits

-partial denture clasp around an abutment tooth

-periapical pathology causing extrusion of the tooth

-physical blow to a tooth

-ortho movement of teeth

secondary occlusal trauma

-normal or excessive occlusal forces exceed the adaptive range of a periodontium that is already affected by bone loss

-bone levels are inadequate to support occlusal forces and tooth less resistant to occlusal loading, therefore occlusal trauma can result even if forces are WNL

factors affecting the response to normal and abnormal forces

-size and shape of roots

-quantity and quality of bone

-presence of microbial biofilm/periodontitis

-missing teeth

-shifted teeth

-parafunctional habits (bruxism, clenching)

-increased duration/frequency of parafunctional habits which may alter direction

acute trauma from occlusion

-cause by abrupt change in occlusal forces (high resto, biting a hard object)

-pain, percussion, sensitivity, mobility

-tearing of PDL fibers, inflammation

acute trauma from occlusion: how might the periodontium react?

-attempt to remove the excessive force by wearing away or shifting the position of the tooth

-periodontal necrosis or periodontal abscess formation

-development of chronic trauma from occlusion (less symptoms)

-development of cemental tears (histologically)

chronic trauma from occlusion

-more gradual changes

-more common than acute

-slow onset w/ less severe symptoms

-usually develops from gradual changes in the periodontium rather than from acute trauma (w/ malocclusions, wear, drifting/extrusions, parafunctional habits)

clinical signs & symptoms of occlusal trauma

-mobility: most common clinical sign (fremitus)

-migration of teeth

-sens to biting, percussion

-hypersensitivity

-abfractions

-wear facets, excessive wear, attrition

-neuromuscular disturbances, parafunctional habits

-TMJ dysfunction

-cusp or tooth fractures, plunger cusps

periodontal changes produced by a traumatic occlusion

-mobility (most common)

-widened PDL (caused by compression & tension of PDL fibers)

-vertical bone loss in the presence of periodontitis

radiographic signs of trauma from occlusion

-widening of the crestal portion (crestal funnelling) of the PDL and thickening of lamina dura

-irregular widening of the entire PDL

-if periodontitis is present, there may be a tendency for vertical or angular bone loss patterns

-osteosclerosis (loc area of increased bone density)

-hypercementosis

-root resorption

physiologic effect of insufficient occlusal forces

-thinning of the PDL space

-loosely arranged PDL fibers

-decrease in density of bone trabeculae

stages of trauma from occlusion

1. injury (depends on magnitude, direction and frequency of forces)

2. slight excess pressure causes compression of PDL and bone resorption

3. slight excess tension causes stretching of PDL and bone formation

4. severe forces cause tearing of PDL

5. repair (damaged tissue is removed & new tissue is formed- PDL, alveolar bone and cementum)

6. if chronic, may result in widened PDL on radiograph (longer fibers histologically, normal vasculature and normal bone)

7. adaptive remodelling (tooth/periodontium relationship adapts and remodels to positions that are no longer injurious and capable of withstanding occlusal forces

8. tooth wear and tooth movement

buttressing/bundle bone

-new bone formed in areas of bone resorption

factors that reduce the resistance of the periodontium to occlusal forces

-loss of alveolar bone and PDL support

-loss of number of teeth

prognosis of teeth affected w/ occlusal trauma

-depends on control over etiology and amount of remaining support

-may be good if amount of remaining support is good

therapy for primary occlusal trauma

-therapy for periodontal disease

-refer to DMD

-occlusal adjustment

-referral for ortho

-bite planes, ngs and/or stress reduction programs to decrease parafunctional habits

-occlusal rehabilitation/prosthodontic tx

therapy for secondary occlusal trauma

-similar to primary

-may include splinting

occlusal adjustments/equilibration

-occasionally indicated on a preventative basis

-want to avoid a positive occlusal sense (individual is always aware of their occlusion)

-in absence of clinical signs & symptoms, outcome assessment to obtain a conceptualized ideal occlusal pattern provides little or no benefit to the client

outcomes assessment

-client should be comfortable

-stability of signs & symptoms

-resolution of mobility

-if levels of bone compromised, mobility may persist

-no further migration of teeth

-radiographic changes diminish or become stable

-relief of pain, premature contacts, fremitus and interferences

important for the overall management of the pt

-role of DH in identification of occlusal trauma

what can help minimize the effects of plaque in areas of occlusal trauma

-a plan for perio therapy for occlusal trauma in conjunction w/ perio therapy

what is helpful in diagnosis

-radiographs