Exam 1

Question 1

What is an abutment?

Answer 1

• part of a structure that directly receives thrust or pressure
• a tooth/portion of a tooth or that partion of a dental implant that serves to support and/or retain a prosthesis

Question 2

What is a retainer?

Answer 2

-any type of device used for the stabilization or retention of a prosthesis

Question 3

What is a pontic?

Answer 3

-an artificial tooth on a fixed dental prosthesis that replaces a missing natural tooth, restores its function, and usually fills the space previously occupied by the clinical crown

Question 4

What are the main biologic considerations for an FDP?

Answer 4

• prevention of adjacent tooth damage, soft tissue damage or pulpal injury
• conservation of tooth structure
• future dental health

Question 5

What are the mechanical considerations for an FDP

Answer 5

• retention
• resistance
• preventing deformation of the restoration

Question 6

What are the esthetic considerations for an FDP?

Answer 6

• all ceramic
• metal ceramic
• material considerations

Question 7

What are some of the main ways to conserve tooth structure?

Answer 7

• partial coverage crowns
• minimum practical convergence angle
• follow anatomic planes to give uniform thickness
• selection of conservative margin geometry
• avoid unnecessary apical extension of the preparation

Question 8

Porcelain margins can be finished to what closeness of cement?

Answer 8

-50 micrometers

Question 9

What issues are created by irregular/rough margins?q

Answer 9

-reduction of adaptation accuracy of restoration

Question 10

What are the benefits of supragingival margin placement?

Answer 10

• no soft tissue trauma
• easy to clean
• easier impression
• easy to evaluate

Question 11

What are conditions requiring a subgingival margin?

Answer 11

• dental caries, cervical erosion, or esthetic zone
• proximal contact extends to gingival crest
• additional retention/resistance needed
• root sensitivity
• associated with RPD

Question 12

What are the advantages of diagnostic casts?

Answer 12

• for fixed restorations
• fabrication of provisionals
• fabrication of custom trays

Question 13

Mounted diagnostic casts are used for what?

Answer 13

• evaluation of occlusal plane
• interarch clearance
• treatment position
• change in VDO
• occlusal analysis
• esthetic analysis

Question 14

What are the three components of retention?

Answer 14

• taper
• length
• surface area

Question 15

What is total axial convergence?

Answer 15

-sum of the taper of two opposing preparation walls

Question 16

What is the sloped shoulder margin design used for?

Answer 16

• PFM crowns FPD
• no metal collar
• improved esthetics
• less intrusion into gingival crevice
• simple laboratory construction

Question 17

What are the disadvantages of a sloped shoulder?

Answer 17

• more difficult preparation
• greater marginal creep
• rough marginal area
• potential gray line
• lab tends to overcontour
• higher lab cost

Question 18

What are the absolute indications of the porcelain butt margin?

Answer 18

• minimal sulcus depth of 1mm or less
• thin labial tissue
• high smile line

Question 19

What are the real indications of the porcelain butt margin?

Answer 19

• margins in the esthetic zone

- which is where the patient says it is

Question 20

What is ante’s law?

Answer 20

• in order to maintain a stable FPD, there are several considerations
• the total periodontal membrane area of the abutment teeth must equal or exceed that of the teeth to be replaced
• extensions of the primary abutment must correspond to the distance of the lever arm that the pontics exert

Question 21

For extended restorations, what are some options in order to not have an FPD fail?

Answer 21

• non-rigid connectors

- cantilever pontic

Question 22

What are ceramics?

Answer 22

-products made from a non-metallic inorganic material processed by firing at high temp to achieve desirable properties

Question 23

First porcelain jacket crown by Pierre Fauchard was made when?

Answer 23

-1800

Question 24

First ceramic crown was introduced by charles lind when?

Answer 24

-1903

Question 25

Which fusion groups of dental ceramics are used for denture teeth and porcelain jacket crowns?

Answer 25

-High and medium fusion 1090-1370*C

Question 26

Which fusion groups of dental ceramics are used for metal ceramic crowns?

Answer 26

-Low and ultra-low fusion <1070*C

Question 27

What is feldspar?

Answer 27

- naturally occurring glass that contains silica, fluxes and alumina all neatly bound together - fused @ high temp

Question 28

What is a frit?

Answer 28

-small fragments generated by the fracture of dental porcelain when Feldspar, quartz and other oxides are heated @ high temp

Question 29

How thick does the metal for the FDP have to be?

Answer 29

-0.5mm

Question 30

Metal surfaces are prepared to receive porcelain with what grinding stone?

Answer 30

-pink

Question 31

How are metal crowns oxidiized?

Answer 31

-fired in air in oven 1200-1900*F

Question 32

What are the 3 types of porcelain particles used in MCCs?

Answer 32

- opaque- containing opacifying oxides - body/dentin porcelain- translucent and contains metal oxides that give base color selected - incisal/enamel- more translucent than body porcelain

Question 33

What is the process of opaque application?

Answer 33

- mix paste, apply with paintbrush and bake | - bake @ 1800*F 1min under vacuum

Question 34

What burs are safe for the adjustment of metal ceramic and ACC?

Answer 34

-low speed handpiece with stones or diamond burs designed for porcelain

Question 35

What do you have to do before the 2nd bake?

Answer 35

-clean crown in ultrasonic and add porcelain to deficient areas

Question 36

What are the advantages to the porcelain labial margin?

Answer 36

- improve esthetics | - less plaque retention

Question 37

What are the disadvantages to the porcelain labial margin?

Answer 37

- inferior marginal adaptation compared to cast metal - decreased strength - more time consuming/difficult - more expensive

Question 38

What are the advantages of the direct lift technique?

Answer 38

-least time consuming

Question 39

What are the disadvantages of the direct lift technique?

Answer 39

- shoulder porcelain needed | - slightly rough margins

Question 40

What is a lucia jig?

Answer 40

used to maintain VDO in CR | like an incisal guide table

Question 41

What is the main reason for FPD failure?

Answer 41

-Caries

Question 42

What are the main considerations for success of the FPD?

Answer 42

- minimize sliding contacts - establish anterior guidance - have opposing contacts in same material - control parafunction

Question 43

What is the distance from the junction between two materials that occlusal contacts have to be?

Answer 43

-1.5 mm

Question 44

What is the mechanism for glass-to-metal bonding?

Answer 44

- glass will adhere to clean, gas-free metal if covered with adherent oxide and temperature raised where oxide is partially dissolved into glass - strain free if coefficients of thermal expansion are the same over the entire temperature range

Question 45

What is adhesive failure @ the porcelain metal interface of an MCC?

Answer 45

-happens @ porcelain metal interface due to missing oxide layer (lab problem)

Question 46

What is adhesive failure @ metal-oxide - metal interface due to?

Answer 46

-contaminated metal (lab problem)

Question 47

What is adhesive failure at the porcelain - metal-oxide interface due to ?

Answer 47

-contaminate metal oxide (lab problem)

Question 48

What is cohesive failure in the porcelain due to?

Answer 48

-maximum strength reached (patient problem)

Question 49

What is cohesive failure in metal oxide due to?

Answer 49

-excessive oxidation (lab problem)

Question 50

What are the key characteristics of framework design?

Answer 50

- even porcelain thickness (established by waxing) - rounded internal angles - 90* metal/porcelain junction - Porcelain wrap around - metal thickness at least 0.3 mm