Perio Flashcards
What is the basic definition of occlusion in general dictionaries?
The act of closure or being closed.
What does the dental definition of occlusion include?
It includes the static, morphological tooth contact relationship and factors related to masticatory system stability and function.
What is the primary role of occlusion in oral motor behavior?
It involves the use of teeth in functional and parafunctional activities.
Define occlusal trauma.
Injury resulting in tissue changes within the attachment apparatus due to occlusal force.
Define occlusal traumatism.
Functional loading of teeth off-axis, sufficient to induce temporary or permanent changes in teeth or supporting structures.
What is acute trauma from occlusion?
Abrupt occlusal impact with high magnitude and short duration, often caused by biting on hard objects.
What is chronic trauma from occlusion?
Gradual changes due to tooth wear, drifting, or parafunctional habits like bruxism, with low magnitude and long duration.
What is primary occlusal trauma?
Tissue changes due to excessive occlusal forces on teeth with normal support.
What is secondary occlusal trauma?
Tissue changes due to normal or excessive occlusal forces on teeth with reduced support.
What type of force is mainly produced during mastication?
Compression forces produced by the masseter muscle.
What type of force acts on anterior teeth during mastication?
Shear forces with a horizontal component.
What type of force acts on posterior teeth during mastication?
Compressive forces with a vertical component.
Why are horizontal forces more detrimental in occlusal traumatism?
They lead to tipping, rocking, and misplacing of teeth.
What are th anatomical actions during centric relation (CR)?
TMJ is at rest, and muscles hold the jaw in the least strained position.
What anatomical changes occur during centric occlusion (CO)?
Teeth take over the load when maximum intercuspation occurs, supported by muscles.
What is fremitus?
A palpable or visible movement of a tooth when subjected to occlusal forces.
How is tooth mobility graded?
Grade 0: Physiological; Grade 1: <1 mm total; Grade 2: >1 mm total; Grade 3: Vertical displacement.
What is a widened PDL space a sign of?
It indicates occlusal trauma or increased mobility.
What clinical sign occurs in occlusal trauma involving the gingiva?
Gingival recession caused by direct contact or functional overload.
What radiographic feature may indicate root resorption?
A visible resorption of root structure on X-rays.
What are the three stages of tissue response to occlusal trauma?
Injury, repair, and adaptive remodeling.
What occurs during the injury phase of occlusal trauma?
Bone resorption under pressure and PDL fiber tearing under tension.
What happens during the repair phase?
Damaged tissues are replaced with new bone, cementum, and connective tissue.
What is the purpose of adaptive remodeling?
To create a structural relationship where forces are no longer injurious.
What is the direction of forces during functional activity?
Vertical forces increase while horizontal forces decrease.
What is the magnitude of force during functional activity?
20-30 lbs.
What is the duration of functional activity daily?
About 20 minutes per day during eating and swallowing.
What is the direction of forces during parafunctional activity?
Horizontal forces increase, causing tipping and rocking of teeth.
What is the force magnitude during parafunctional activity?
250-300 lbs.
What is the duration of parafunctional activity?
About 40 minutes per hour due to habits like clenching and bruxism.
Why are natural teeth more adaptive to forces compared to implants?
Natural teeth have a periodontal ligament, which absorbs and distributes forces.
What type of forces are implants most vulnerable to?
Excessive occlusal forces, especially horizontal and cantilever forces.
How do implants respond to excessive occlusal forces?
They may cause crestal bone resorption and loss of osseointegration.
What is the significance of bone density in implant occlusion?
Lower density bones (like D4) are more susceptible to overloading and bone loss.
Why should maximum intercuspation be avoided in implants?
Implants lack proprioceptors in the PDL, leading to uncontrolled force distribution.
What is a common overloading factor for implants?
Overextended cantilevers or large occlusal tables.
What is the treatment focus for primary occlusal trauma?
Occlusal adjustment to prevent further tissue damage.
What is the first step in treating secondary occlusal trauma?
Addressing inflammation with scaling, root planing, and oral hygiene measures.
How does occlusal adjustment help in periodontitis cases?
It reduces mobility and enhances periodontal healing.
When is splinting necessary in cases of occlusal trauma?
For mobile teeth with a healthy but reduced periodontium to increase comfort and prevent fractures.
What are signs that occlusal adjustment may improve periodontal treatment outcomes?
Premature contacts, fremitus, or cervical abfraction.
What is the modulus of elasticity of natural tooth structures?
Ranges from 9 psi for bone to 14 psi for dentin and cementum.
Why is ferrule height critical in post-and-core restorations?
It dissipates occlusal forces, reducing stress concentration and failure.
How much ferrule height is needed for anterior teeth?
2 mm on both labial and lingual surfaces.
How do horizontal forces affect anterior teeth with posts?
Stress concentration occurs at the cement line or post-to-tooth junction, risking failure.
What happens if excessive occlusal forces act on dental implants?
They can lead to crestal bone resorption due to force concentration at the bone-implant junction.
How should implant designs differ from natural teeth?
Avoid rules of natural teeth; ensure force distribution aligns with implant limitations.
Why is bone remodeling more significant in implants under excessive force?
The mismatch in modulus of elasticity between implants and bone concentrates forces at weak points.
