Post on 14-Apr-2018
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Esthetic consideration ingingival tissue
management
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THE ELEMENTS OF THE OCCLUSAL EQUATION
Occlusion in the natural dentition is characterized by the
following features:
Highly variable occlusal schemes
In many cases, a high degree of adaptation
Can be satisfactory even when several teeth aremissing
The mandible flexes during maximal opening andprotrusion
The condyle can shift causing interferences withposterior morphology (Bennett movement)
The patients envelope of function varies with thepatients position and activity
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Occlusion that is developed in a prosthetic
rehabilitation should have the following features:
Mutual protection between anterior teeth and
posterior teeth, teeth on the working side and
teeth on the non-working side
Bilateral posterior contact
Efficient anterior guidance that discludes all
posterior teeth
Canine guidance or group function
Muscular comfort
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The determinants of occlusion can be divided in anterior and posterior:
ANTERIOR
Overbite
Overjet
POSTERIOR
Intercondylar distance
Condylar guidance
Side shift (ISS, PSS)
Curve of Wilson
Curve of Spee
Occlusal plane inclination
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Anterior guidance
the influence of the contacting surfaces of teethon tooth limiting mandibular movements
It is the consequence of the interaction between
overbite and overjet which influence its efficacy
The less effective the incisal guidance, the more
important are the posterior determinants
of occlusion.
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Overbite
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Overjet
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MagnitudeWidening of periodontal ligament space
Increase in number and width of the periodontal fibersIncrease in density of alveolar bone
DirectionReorientation of stresses and strains withinperiodontium
Lateral and torque forces injure the periodontium
DurationConstant pressure is more injurious than intermittentpressure
FrequencyThe more frequent the application of an intermittentforce, the more injurious
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Excessive occlusal forces
Disrupt the function of the masticatory
musculature
Cause painful muscle spasmsInjure temporomandibular joint
Produce excessive tooth wear
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Acute trauma
Results from an abrupt occlusal impact
Biting on a hard object (cherry seeds)
New tooth restorations or prostheses
Chronic trauma
Develops from gradual changes in occlusion
Produced by tooth wear, drifting of teeth,
extrusion, parafunctional habits
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Traumatic occlusal relationships a.k.a.
Occlusal disharmony
Functional imbalance
Occlusal dystrophy
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Primary trauma from occlusion
Result of alterations in occlusal forces
High restorative fillings
Isertion of prosthesis that creates excessive forceson abutments and antagonists
Normal periodontium with normal height of bone
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Secondary trauma from occlusion
Reduced ability of the tissues to resist occlusal
forces
Adaptive capacity of tissues are impaired dueperiodontal inflammation that results to bone loss
Periodontium becomes more vulnerable to injury
Normal periodontium with normal height of bone
Marginal periodontitis with reduced height of bone
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Stages of Tissue Response
Injury
Repair
Adaptive remodeling
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Injury
Produced by excessive occlusl forces
Chronic force periodontium is remodeled to cushion
impact
Periodontal ligament is widened at the expense of the
bone, results in nagular defects withoiut periodontal
pockets
Tooth becomes loose
Furcations most susceptible to injury of the
periodonitum
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Repair
Constantly occuring in the normal periodontium
Trauma from occlusion stimulates reparative
activity
Damaged tissues are removed
New connective tissue cells and fibers, bone and
cementum are formed to attempt restoration of
injured periodontium
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When bone is resorbed by occlusal forces, it
attempts to reinforce the thinned bony trabeculae
with new bone - buttresing bone formation
Also occurs when bone is destroyed byinflammation and osteolytic tumors
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Adaptive Remodeling of
PeriodontiumIf repair process cant keep pace with the
destruction , the periodontium is remodeled in an
effort to create structural relationship in which the
forces are no longer injurious to the tissues
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Effects of insufficient occlusal force
May also be injurious to the supporting
periodontal tissues
Hypofuntion can result from
Open-bite relationship
Ansence in functional antagonists
Unilateral chewing habits
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Insufficient stimulation causes
thinning of periodontal ligament
Atrophy of fibersOsteoporosis of alveolar bone
Reduction in alveolar bone height