PROSTH Flashcards
The four types of elastomeric impression materials are
polysulfides
condensation silicones
addition silicones
polyethers.
Surface moisture is not good for elastomeric impression materials because the moisture decreases the accuracy of the impression.
No moisture in which impression material
polyether
Origin and insertion of Lateral Ptrerygoid muscle
- Superior Pterygoid
O = Infratemporal aspect of sphenoid wing
I = 60% neck of condyle 30% disc - Inferior Pterygoid
O = lateral wing of sphenoid
I = Neck of condyle
Medial Pterygoid muscle origin insertion action
Origin: Medial surface of lateral pterygoid plate Insertion: Medial surface of the ramus
Action: Elevates the mandible
Temporalis muscle origin insertion action
Origin: Lateral surface of skull
Insertion: Coronoid process /Anterior border of ramus
ACTION: Anterior part elevates the mandible Posterior part retrudes mandible
Masseter muscle origin insertion action
Origin: Zygomatic arch
Insertion: Lateral surface of ramus/ Coronoid process
Action: Elevates the mandible
Muscles of Masstication (4)
- Temporalis
- Masseter
- Lateral Pterygoid
- Medial Pterygoid
Center of resistance –
half the distance from alveolar crest to root apex (translation)
*During rotation movements: center of rotation=center of resistance
Superior Lateral Pterygoid origin insertion action
Origin: Infratemporal aspect of the sphenoid wing
Insertion: - 60% of fibers attach to neck of condyle
- 30% attach to the disc
Action: - Works together with elevator muscles
Center of rotation:
Apical to center of resistance (apical to halfway down root) –during translation movements and tipping movements
- During rotation movements: center of rotation=center of resistance
Lateral Pterygoid origin insertion action
Origin: Lateral wing of the sphenoid
Insertion: - Neck of the condyle
Action: - Unilateral contraction: mediotrusive movement of that condyle and lateral movement of the mandible to the opposite side.
There are five major sources of dimensional change:
polymerization shrinkage, loss of a by-product, thermal contraction, imbibition (absorb H2O) and incomplete recovery of deformation because of viscoelastic behavior.
what are the biological principles of tooth prep/ifxed
- conservation ot tooth strx
- preservation of gingival tissues
- Marginal intergrity
WHat are the mechanical principle of tooth preps/fixed?
- Rentension
- Resistance
- Structual durability
Which position is the most reproducible for restorative dentistry?
CR
CR = Tooth-independent ; det by condyles/ligament in condyles in the superior/anterior most position w/i the glenoid fossa
A porcelain-fused-to-metal (PFM) crown preparation requires which of the following margins?
chamfer margin on the lingual
1mm+ shoulder margin on the facial.
The force magnitud/duration during mastication is
very heavy, and the force duration is very short.
The force magnitude/duration during swallowing is
MOD force ; Short Duration
The force magnitude/duration during speaking is
Light Force ; Very short Duration
MOD Force ; Varible duration is the force magnitude/duration for?
Either habits or Orthodontics
Irreversible hydrocolloid aka _____ is a flexible impression material that is most commonly used to obtain study models. It is susceptible to ____2____ and ____3____, which leads to deformation and should be poured with stone as soon as possible.
- alginate
- imbibition (gain or loss of water)
- syneresis (quick drying)
Alginate sets up by calcium sulfate reacting with alginate to produce insoluble calcium alginate, which demonstrates a gel consistency.
2 designs in tooth preparation can be used with all-ceramic crowns?
(Butt-joint) SHOULDER or CHAMFER
A protrusive jaw relation record is made in order to set the
A- Horizontal condylar inclination of the articulator
B- Anterior guide table of the articulator
C- Lateral condylar guidance of the articulator
D- Lateral translation of the articulator
A
Clicking of the dentures during speech most often indicates which of the following?
A- Inadequate denture retention
B- Decreases occlusal vertical dimension
C- Insufficient interocclusal space
D- Improper buccolingual position of the teeth
C
Which of the following explains why proper contouring of the axial surface of complete cast restorations is extremely important?
A- Retention
B- Occlusal wear
C- Effect on gingival tissue health
D- Ability to provide caries resistance
C
______________ is a flexible impression material that contains agar-agar as a primary component. It undergoes a physical reaction (from a sol-to-gel state).
- Reversible hydrocolloid
Reversible hydrocolloids require the use of specialized trays and water baths.
Which of the following refers to a decreased occlusal vertical dimension?
A- Vertical dimension that leaves the teeth in a clenched, closed relation in normal position
B- Occluding vertical dimension that results in a excessive interocclusal clearance when the mandible is in rest position
C- Insufficient amount of interarch distance because of the bony ridges
D- Condition in which the patient cannot open mandible because of temporomandibular joint pathology
B
Pressure on the midpalatine suture will improve
A- Denture retention only
B- Denture stability only
C- Both denture retention and denture stability
D- Neither denture retention nor denture stability
D - it’s a relief area
A protrusive jaw relation record is made in order to set the
A- Horizontal condylar inclination of the articulator
B- Anterior guide table of the articulator
C- Lateral condylar guidance of the articulator
D- Lateral translation of the articulator
A
Irreversible hydrocolloids contain two phases as follows:
First phase : Second phase :
- (soln): the material is a liquid or semiliquid.
2. (gel): the material is semisolid and is similar to a gelatin dessert.
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___1____rubber is an _____ impression material that undergoes a chemical change. It is relatively rigid with good tissue detail but is unstable in the presence of ______.
- Polyether
- elastomeric
- moisture
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____1____ rubber is an ___2____ impression material that undergoes a chemical change to produce a rigid and foul-smelling impression with good detail and _____3___.
- Polysulfide
- elastomeric
- dimensional stability
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For procedures using the lathe, the following should be utilized:
Use fresh pumice each time.
Use disposable trays.
Use sterile (steam sterilize) or disposable rag wheels
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1
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What can you expect to see in pt with Muscle dystrophy ?
lower face with open bite.
concern w/ LA: Increase risk of tox (lido)
______1____ is an ____2____ silicone that is utilized to obtain precision impression for prosthodontic fabrication.
- Polyvinylsiloxane
2. addition
