Gold/PFM Crown + Preparation

high noble

What type of metal for crowns:

- 60-40% noble metal

- must be gold

advantages:

- Excellent biocompatibility

- Excellent corrosion resistance

- Minimal wear to opposing teeth

disadvantages:

- expensive

noble

What type of metal for crowns:

- at least 25% noble metal

advantages:

- Good biocompatibility

- Good corrosion resistance

- Lower in cost

disadvantages:

- still expensive

base

What type of metal for crowns:

- less than 25% noble metal

advantages:

- Lowest cost

- Strongest

disadvantages:

- often contains high nickle which patients can be sensitive to

conservative

an advantage of full coverage of metal crowns is the prep is the most ...... of tooth structure

last

the head diameter of a bur is signified by the .... number

band color

The grit of a high speed bur is dignified by the .....

occlusal grooves

the first step in crown prep is occlusal depth cut in .....

half

the second step in crown prep is prepare the occlusal surface of .... of the tooth

functional cusp bevel

the .... ensures optimum restoration contour with maximum durability and conservation of tooth structure

45

on most teeth, the functional cusp bevel is placed approximately ..... degrees to the long axis

buccal

The functional cusp bevel for the mandibular teeth is on the .... cusps

lingual

The functional cusp bevel for the maxillary teeth is on the .... cusps

occlusal

the 2b step in crown prep is completing preparation of the ..... surface

axial

the third step in crown prep is buccal and lingual .... depth cuts

line angles

the fourth step in crown prep is completing preparation of the buccal and lingual surfaces to .....

break contact

the fifth step in crown prep is interproximal preparation using a ..... bur

6

the finished crown prep should have a .... degree taper

chamfer

The margin for gold and PFM crown preps is ....

one

it is best to check for under cuts with .... eye

feldspathic

the procelain used in PFM is .... porcelain

opaque

which layer of porcelain in PFM crowns:

- conceals metal

- aids in bond between porcelain and metal

dentin

which layer of porcelain in PFM crowns:

- most of the bulk of the crown

enamel

which layer of porcelain in PFM crowns:

- more translucent

- helps crown blend with natural teeth

coefficient of thermal expansion

for porcelain to stay bonded to the metal their ..... must be compatible

chemical

.... bonding is the most significant factor in porcelain and metal bonding

mechanical

The metal is roughed with sand blasting before the opaque porcelain layer is applied to aid in ... bonding

compression

The metal expanding more during heating and the porcelain shrinking more during cooling attributes for .... bonding between the metal and porcelain

2

the porcelain of a PFM crown can not be more than ... mm thick

disappearing metal

what type of PFM crown margin:

- metal, opaque layer, and all porcelain layers end at the same place

metal collar

what type of PFM crown margin:

- thin band of metal at margin

- linguals of PFM crowns

lingual

a metal collar is used at the .... of PFM crowns

porcelain butt joint

In order to not see metal through porcelain at facial margin of an anterior tooth, porcelain must directly abut the margin. This is call a .....

chamfer; shoulder

the preparation for a PFM crown is ..... on 3 sides and ..... on the facial

less

on advantage of PFM crowns is connector surface area requirement for metal is .... than that for zirconia