FPD Exam 1 | 100% Correct Answers |
Verified | Latest 2024 Version
What is the optimal crown-to-root ratio for FPD abutment teeth? - ✔✔2:3 is the OPTIMAL ratio
1:1 is the maximum acceptable ratio
(You can't have more crowns than roots supporting it)
(E.g. 2 abutment teeth with 3 roots total)
What is Ante's law? - ✔✔Abutment teeth root surface are should be equal to or more than
replaced/pontic teeth
(e.g. A pontic tooth that would normally have 2 roots should have at least 2 (preferably more) roots on
abutment teeth.)
How does deflection (bend) change for 2-tooth vs 3-tooth pontics? - ✔✔If span length is doubled (e.g. 1
tooth to 2 tooth), deflection (bend) will be 8x more.
(number of teeth in the pontic cubed = deflection)
(E.g. 2-tooth = 8x (2^3), 3-tooth = 27x (3^3))
What planes should the abutment teeth be parallel to each other to have effective path of insertion and
draw? - ✔✔Facial plane, buccal plane, and occlusal/incisal plane
Describe the different pontic designs? Which do we use at UDM? - ✔✔Hygenic design: Non-mucosal
contact
Conical design: Small tip, can collect debris
, Ridge lap: Impossible to clean - causes inflammation
Modified ridge lap: Mostly convex surfaces for easy cleaning - the lingual surface is rounded (no contact)
Ovate: Most widely used - tissue contact is blunt and rounded contacting the tissue
At UDM we use modified ridge lap and ovate pontics
Differentiate between cantilever and resin-bonded alternative FPD designs - ✔✔Cantilever = Only uses 1
abutment tooth. Forces TIP the abutment teeth, so it requires teeth with good root support
ONLY ever used for replacing maxillary LATERAL incisors OR molars with no distal abutment available
Resin-bonded FPD: Allows for minimal removal of tooth structure by bonding the pontic to the abutment
teeth with a retainer, but usually don't last as long. Requires covering as much enamel surfaces as
possible for the bonded retainer.
What are the principles behind making sound interims? - ✔✔1. Thermal protection for the tooth
2. Form, function, and esthetics
3. Prevent bacterial ingress
4. Unforseen events like lab delays
OR 5. Deliberate delay
6. Prevent movement of adjacent/opposing teeth
What interim material do we use at UDM? - ✔✔PMMA acrylic (alike)
How should your choice of FPD cement be influenced by your permanent cement choice? - ✔✔If
BONDING your definitive restoration, you CANNOT use eugenol in your temporary cement (it will block
the dentinal tubules preventing bonding)
Choice of temporary cements is based on permanent cement choice
Verified | Latest 2024 Version
What is the optimal crown-to-root ratio for FPD abutment teeth? - ✔✔2:3 is the OPTIMAL ratio
1:1 is the maximum acceptable ratio
(You can't have more crowns than roots supporting it)
(E.g. 2 abutment teeth with 3 roots total)
What is Ante's law? - ✔✔Abutment teeth root surface are should be equal to or more than
replaced/pontic teeth
(e.g. A pontic tooth that would normally have 2 roots should have at least 2 (preferably more) roots on
abutment teeth.)
How does deflection (bend) change for 2-tooth vs 3-tooth pontics? - ✔✔If span length is doubled (e.g. 1
tooth to 2 tooth), deflection (bend) will be 8x more.
(number of teeth in the pontic cubed = deflection)
(E.g. 2-tooth = 8x (2^3), 3-tooth = 27x (3^3))
What planes should the abutment teeth be parallel to each other to have effective path of insertion and
draw? - ✔✔Facial plane, buccal plane, and occlusal/incisal plane
Describe the different pontic designs? Which do we use at UDM? - ✔✔Hygenic design: Non-mucosal
contact
Conical design: Small tip, can collect debris
, Ridge lap: Impossible to clean - causes inflammation
Modified ridge lap: Mostly convex surfaces for easy cleaning - the lingual surface is rounded (no contact)
Ovate: Most widely used - tissue contact is blunt and rounded contacting the tissue
At UDM we use modified ridge lap and ovate pontics
Differentiate between cantilever and resin-bonded alternative FPD designs - ✔✔Cantilever = Only uses 1
abutment tooth. Forces TIP the abutment teeth, so it requires teeth with good root support
ONLY ever used for replacing maxillary LATERAL incisors OR molars with no distal abutment available
Resin-bonded FPD: Allows for minimal removal of tooth structure by bonding the pontic to the abutment
teeth with a retainer, but usually don't last as long. Requires covering as much enamel surfaces as
possible for the bonded retainer.
What are the principles behind making sound interims? - ✔✔1. Thermal protection for the tooth
2. Form, function, and esthetics
3. Prevent bacterial ingress
4. Unforseen events like lab delays
OR 5. Deliberate delay
6. Prevent movement of adjacent/opposing teeth
What interim material do we use at UDM? - ✔✔PMMA acrylic (alike)
How should your choice of FPD cement be influenced by your permanent cement choice? - ✔✔If
BONDING your definitive restoration, you CANNOT use eugenol in your temporary cement (it will block
the dentinal tubules preventing bonding)
Choice of temporary cements is based on permanent cement choice
