Abutment Assessment and Tx Planning (Combined) Flashcards
What are 3 options for replacing a missing tooth?
- RPD
- FPD tooth supported
- FPD implant supported
What are the indications for an RPD?
- Edentulous space >2 posterior teeth
- Edentulous space > 4 incisors
- Edentulous space that includes a canine and 2 other contiguous teeth
- No distal abutment
What are the indications for a Fixed Partial Denture?
- Abutment teeth bound edentulous space
- Abutments periodontally sound
- Retainers designed and executed well
- Patient highly motivated
- Patient can afford the treatment
- No gross soft tissue defect in edentulous ridge
What are some contraindications for FPD?
- Dry mouth (caries risk)
- Short clinical crown teeth
- Tipped teeth adjoining edentulous space
What is a conservative restoration that is reserved for use on defect-free abutments in situations where there is a single missing tooth, usually an incisor or premolar?
Resin bonded tooth supported FPD
Why is a resin-bonded FPD useful in younger patients whos immature teeth with large pulps?
It requires shallow prep only into enamel decreasing pulp exposure risk
What are 3 things to consider when evaluating abutment teeth for FPD?
- Crown:Root ratio
- Root configuration
- PDL
What is the optimum crown tp root ratio for a tooth to be utilized as a FPD abutment?
2:3, 1:1 is minimum
When could a crown to root ratio of less than 1:1 be acceptable for an FPD abutment tooth?
If abutment opposes another FPD because occlusal load will be less
Is the crown to root ratio alone an adequate criteria for evaluating a prosprective abutment tooth?
No
What is the preferable root configuration for an abutment tooth: broader labiolingually than mesiodistally, or roots that are round in cross section?
- Roots broader labiolingually than MD
- Conicals useful in short span FPD
- Wider spaced roots in posterior more favorable
- If conical root has bends it is more favorable than straight tapered root
What principles states that the root surface area of the abutment teeth has to equal or surpass that of the teeth being replaced with pontics?
Ante’s law
What is a general biomechanical consideration with FPD?
Longer spans are less rigid
What can be done to increase the rigidity of FPD?
Increase pontic occlusal-gingival dimension or create out of higher yield alloy
Dislodging forces on and FPD work in which direction?
Mesiodistal
What can be used to reinforce a long span or an unfavorable crown to root ratio on an abutment tooth?
Secondary abutment = double abutments
Which teeth are more retentive: tall or short teeth?
Tall, e.g. PM > M (whatever that means)
What is a common problem when replacing all four maxillary incisors?
Pontics lie outside interabutment axis line and create torque on abutments
How far must secondary retention be on an anterior FPD to counteract the tourquing?
Secondary abutments must be the same distance posterior of the abutment axis line as the pontics are anterior of the interabutment axis line
When would a pier abutment occur?
Edentulous space occurring on both sides of a tooth
What is a means to get around from a pier abutment acting as a fulcrum for movement of a nFPD?
Use a nonrigid connector for the pontic to retainer, usually placed on the middle abutment. Book example is a T-link
What is the term for a FPD with an abutment or abutments at one end only. They should usually only replace one tooth and have 2 abutment teeth.
Cantilever FPD
What is the treatment of choice when an abutment molar is tilted?
Orthodontic uprighting
What are 4 things that can be done if an abutment molar is tilted and cannot be uprighted via ortho?
- Recontour M surface of 3rd molar to allow path of insertion onto the 2nd molar abutment
- Proximal 1⁄2 crown on distal(tilted) abutment
- Telescoping crown on distal(tilted) abutment
- Nonrigid connector on mesial abutment tooth (premolar)
