Mcqs Flashcards
Degree of roughness with yellow colour:
Super fine Extra fine Fine Standard-medium Coarse Super coarse
extra fine
Degree of roughness with black colour:
Super fine Extra fine Fine Standard-medium Coarse Super coarse
super coarse
Degree of roughness with green colour:
Super fine Extra fine Fine Standard-medium Coarse Super coarse
coarse
Degree of roughness with blue colour:
Super fine Extra fine Fine Standard-medium Coarse Super coarse
standard-medium
Degree of roughness with red colour:
Super fine Extra fine Fine Standard-medium Coarse Super coarse
fine
Degree of roughness with white colour:
Super fine Extra fine Fine Standard-medium Coarse Super coarse
super fine
Coding of burs takes into account the following:
material shape roughness/ grain size diameter compatible handpieces
Speed definition:
= # or revolution per minute (rpm)
/ = the # of times a rotating instrument (ex: bur) wil make a full turn during a minute
Slow speed rpm:
<12.000rpm
Medium or intermediate speed:
12.000-20.000rpm
High speed:
20.000rpm
Carbide bur used at a speed:
slow speed
UNC - 15 probe use:
- used together w/ putty indices to measure reductions
- periodontal pockets and biological width measurement
- shoulder margin
- cement removal
Williams probe use:
- periodontal pockets and biological width measurement
- shoulder margin
- cement removal
BPE probe use:
- periodontal pockets and biological width measurement
- cement removal
Straight probe:
- mainly access the margins of a crown
- w/ care to remove excess cement
NO pocket depths
Flat plastic use:
- to remove the provision crown
- to shape provision crown
Front surface mirror:
produces a clear mirror image w/o distruction
Concave mirror:
produces a magnified shape
can disort the image
Plane (flat) surface mirror:
- produces a double images
- resists scratching and its durable b/c reflecting surface is on the back
Retention form
=To prevent displacement of a cemented restoration along any its paths of insertion, including the long axis preparation
Resistance form
=To prevent displacement of a cemented restoration by apical or obliquely-directed forces
Conservation form
=to avoid weakening unnecessarily the tooth and avoid pulp compromising
Structural Durability
=to prevent enough space for a crown which will be sufficiently thick to prevent fracture
Why do we bevel the functional cusp?
- gives space for the opposing cusp to move freely
- prevents working side interference
What is convergence angle?
=angle b/w 2 opposing walls
- 6 degrees
Seating groove definition:
- to avoid rotation
- to increase retention
Construction of a temporary crown in a lab VS dental office
in lab: better aesthetics, expensive, more time consuming
Prefabricated crowns for anterior teeth:
celluloid
polycarbonate
metal aluminum
celluloid
polycarbonate
Prefabricated crowns for posterior teeth:
celluloid
polycarbonate
metal aluminum
celluloid
polycarbonate
or metal aluminum
Advantages of temporary crowns:
- protects open dentin tubules from micro leakage
- maintain occlusal relationship
- maintain interdental space and contacts
- prevents gingival hyperplasia
- protects cheeks,tongue,lips from trauma
- maintains appearance
Advantages of provisional crowns:
check:
- changes in occlusion if acceptable
- phonetics
- appearance
- mastication
Temporary VS Provisional crowns:
temporary will come to an end while provisional might not come to an end
In class we used this impression technique:
disposable triple tray impression
Why subgingival preparations need gingival retraction?
- prevent bleeding
- acts as a physical barrier and retract gingival tissues
- allow accurate impression of margin preparations
Best method for soft tissue retraction and how?
chemomechanical: impregnated retraction cord (=soaked in a chemical sol)
- enlarges sulcus
- controls sulcular hemorrhage
solutions: ferric sulfate or aluminium sulfate
Disadvantage of chemomechanical soft tissue retraction?
staining
systemic side effects
inflammation and tissue necrosis
Plain retraction cord aim and disadvantage:
aim: sulcus enlargement
disadvantage: sulcular hemorrhage
Copper band retraction cord aim and disadvantage:
aim: displace the gingivae, ensures finishing line is capsured in the impression
disadvantage: traumatic, not effective, not accurate
Dual cord technique w/ impregnated retraction cord:
thin placed first, thick placed on top
Retraction paste aim, example, advantage:
aim: to create space b/w prepared tooth and sulcus
ex: Al2Cl3
advantage: quicker and easier
Surgical soft tissue retraction methods:
- plain retraction cord
- rotary curettage
- electrosurgery
- copper ring
- impregnated retraction cord
- crown lengthening
- retraction paste
- rotary curettage
- electrosurgery
- crown lengthening
Contraindications with electrosurgery of soft tissue retraction?
- patients with cardiac pacemakers
- not used with topical anesthetics
- not used with flammable aerosols
- avoid contact with bone
- avoid metal instruments or metal restorations
Crown lengthening definition, advantages, disadvantages:
= surgical procedure involving bone removal and gingival re-contouring
advantages:
- aesthetics
- increases crown height
- creates supragingival margins
disadvantages:
- discomfort
- need to allow time for healing
- increased crown:root ratio
Ante’s Law
=combined pericemental area of all abutment teeth supporting a fixed dental prosthesis should be EQUAL to or BIGGER in pericemental area than the tooth or teeth to be placed
Pontic shapes:
hygienic ridge lap modified ridge lap bullet/conical ovate
What are the types of articulators?
- simple hinge articulator
- fixed/mean value condylar path articulator
- adjustable condylar path articulators
1. semi adjustable
2. full adjastable
What is the occlusal reduction of pfm crown?
1.2-2.0mm
What is the occlusal reduction of all ceramic crown?
1.0-1.5mm
What is the occlusal reduction of all metal crown?
1.0-1.5mm
What is the occlusal reduction of zirconia crown?
1.0-1.5mm
What is the occlusal reduction of porcelain fused to zirconia crown?
1.5-2.0mm
What is the incisal reduction reduction of porcelain fused to zirconia crown?
2.0-2.5mm
What is the incisal reduction reduction of pfm crown?
1.5-2.0mm
What is the incisal reduction reduction of all ceramic crown?
1.5-2.0mm
What is the incisal reduction reduction of all metal crown?
1.5-2.0mm
What is the incisal reduction reduction of zirconia crown?
1.5-2.0mm
What is the axial reduction of zirconia crown?
0.5-1.0mm
What is the axial reduction of all ceramic crown?
1.0mm
What is the axial reduction of all metal crown?
0.5mm
What is the axial reduction of pfm crown?
1.2mm
What is the axial reduction of porcelain fused to zirconia crown?
1.5-2.0mm
What is canine guidance?
a. posterior disocclusion of teeth as mandible is retruted
b. posterior occlusion of teeth as maxilla is retruted
c. posterior disocclusion of teeth as mandible is protruded
d. anterior disocclusion of teeth as mandible is protruted
c. posterior disocclusion of teeth as mandible is protruded
What is mutually protected occlusion?
=canine guidance
What is RCP?
=retruted contact position
=its the first tooth contact happening when mandible closes in the terminal hinge axis position
What is bilateral balanced occlusion?
=involves contacts on as many teeth as possible in all excursive movements
What is unilateral balanced occlusion?
=group function; making contact w/ more than 1 tooth when you move your jaw in a sideways motion
What are the condylar paths of movement?
orbiting condyle path
rotating condyle path
protrusive condyle path
What is the diameter of biological width?
2.04mm
What is biological width?
=distance b/w junctional epithelium and supra-alveolar CT
How can you stabilise the restoration?
w/ Disclosing Wax
What is the solution if seating of fixed partial denture is hindered?
light body layered on crown’s internal surface and placed over tooth or die
Which side of articulating paper is placed on the restoration and which on opposing teeth?
red on restoration
black on opposing teeth
What is a luting agent?
=dental cement which attached indirect restoration to tooth
Types of luting agents?
definitive or
provisional
When are provisionals cemented?
during preparation time
and during the time b/w preparation and delivery of the definitive prosthetics
Advantages of provisionals:
- good retention
- good marginal seal
- durability
- easy to clean up
Which cements do we use for aesthetic reasons?
resin cements
Which cements do we use for luting metallic restorations and posts?
conventional glass ionomer
zinc phosphate cements
How do we classify fixed partial dentures?
acoording to the site, material and missing teeth
Bridge designs
- fixed-fixed
- fixed-supported
- fixed-free bridge or cantilever bridge
- spring cantilever bridge
- combinations
Where does fixed-fixed bridge have a rigid connector?
both ends of pontic
Where does fixed-supported bridge have a rigid connector?
at the distal end of the pontic
What is a cantilever bridge?
=bridge attaching to adjacent teeth on one side of it only