9/18: All Ceramic and Metal-Ceramic Crown Preps Flashcards
- A metal-ceramic crown is also known as
PFM
- This type of crown takes the strength of metal and combines it with the tooth matching esthetic ability of porcelain
PFM
- What are the indications for PFM?
a. Opposing teeth are porcelain/ceramic
b. High level of aesthetics is needed
c. Preparation are unusual
d. Bridges and other long span fixed restorations
- Are PFM or all-ceramic crowns more resistant to fractures?
PFM
- Can PFM be used for any tooth?
Yes
- What are the PFM components, specifically the porcelain?
a. Opaque porcelain
b. Body porcelain
c. Incisal porcelain
d. Shoulder porcelain
- What is the minimal thickness of metal in PFM?
a. 0.3-0.5mm
- How much metal coping do you need in PFM?
a. Veneered = 0.3-0.5mm
b. Unveneered area = 0.8-1.00mm
- How much opaque porcelain is needed in PFM?
a. 0.1-0.2mm
- How much shoulder porcelain is needed in PFM?
0.8mm
- How much gingival, body, and incisal porcelain is needed in PFM?
a. 0.8-2mm
- In a PFM, how much metal and porcelain occlusion do you need?
a. 0.5 metal
b. 1.5 porcelain
- What is the importance of 2 plane reduction?
a. Even thickness of material
- You want porcelain esthetics to be carried into what regions?
a. Contact regions so it is not seen from the facial
- Without two planes, what can we endanger?
Pulp
- Why is a modified shoulder preferred on PFMs?
a. Less stress on the tooth
b. Harder to mill to 90 degrees
- What are the types of PFM margin designs?
a. Metal collar → subgingival, 1.2mm
b. Disappearing metal → used when the margin is not deep enough to allow the ceramic and metal to meet, 1.2mm
c. Porcelain →1.2mm, pure esthetics
- Ideally, you want PFMs to be placed how in relation to the gingiva?
a. 0.5mm below
- If the crown margin violates the biological width, what happens?
a. Gingival inflammation and resorption of bone
- This is the crown and tooth contour which preserves the gingiva health
a. Emergence profile
- Porcelain has to be how thick?
a. Less than 3mm
- Is porcelain abrasive to natural dentition?
Yes
- This is the most realistic restoration for esthetics
a. Ceramic
- What is the chemical name of ceramic?
a. Lithium disilicate
b. Lithium silicate
- What are the indications for ceramic?
a. Esthetics
b. Light occlusal load
- What are contraindications for ceramic?
a. Heavy occlusal loads
b. Short prep with ceramic thickness greater than 3mm
- What are the reductions for ceramic?
a. Incisal: 2-2.5
b. Facial: 1.2-1.7
c. Lingual: 1-1.2
d. Margin: 1-1.2
- On what teeth will you do ceramics?
a. Anterior
b. Posterior will not work, not enough room
- What is required 90% of the time with ceramics?
a. Resin cement
- Do ceramics or PFM use e.max?
Ceramics
- E.max is a
a. Glass ceramic
- Is there enough room for a Ceramic on the mandibular 2nd molar?
a. No, you will break
- What increases the strength of a ceramic crown?
a. Resin composite
- More than ____mm porcelain left incisally will result in risk of fracture
3mm
- What is an alternative to ceramics that is becoming increasingly more popular?
PFZ