module 3- FDP Flashcards
group function
multiple contacts on the working side only
mutually protected
anterior teeth protect posterior teeth, and vice versa
balanced occlusion
in dentures, contact on both sides (to provide stability)
what can limit restorative space
over-erupted teeth and tilted teeth
name 3 ideal root configurations for abutment teeth
- divergent roots
- oblong pulp
- multiple roots
define ante’s law
total periodontal attachment area of abutments should equal to or be greater than that of the teeth being replaced
what is the exception for using a weakened abutment tooth for an FPD
if it is opposing a complete denture (due to lower forces)
what 3 things make a good abutment
- good C:R ratio
- ideal root form
- good PDL area (Ante’s law)
what is the relationship between deflection and span length
deflection = (span length factor)^3
if you go from 1 pontic to 2 pontics, what happens to deflection
8x
what tolerates deflection better: metal or ceramics?
metal
name 4 “solutions” to counter deflection/long spans
- grooves (buccal and lingual)
- base metal framework
- good connector space
- double abutments
3 disadvantages of increasing connector space
- poor esthetics
- poor oral hygiene
- poor perio health (impinge on gingiva)
what is the relationship between strength and height of connector space
strength = (height factor)^3
what is the relationship between strength and width of connector space
strength = (width factor)^1
if i increase the height of the connector space by a factor of 2, what happens to the strength?
8x
if i increase the width of the connector space by a factor of 2, what happens to the strength?
2x
A primary abutment has a C:R of 2:3. Which of the following is a good option for double abutment?
a) tooth with 1:1
b) tooth with 2:3
c) tooth with 2:1
d) tooth with 1:2
b) tooth with 2:3
which of the following is the most ideal C:R for an FDP abutment?
a) 1:1
b) 1:2
c) 2:3
d) 2:1
c) 2:3
true or false: a double abutment with a retentive retainer can be used to replace an over-tapered retainer for primary abutment
false. double abutments should not be used because there is poor retention in the primary abutment
where does the non-rigid connector attach to on the pier abutment
on the distal surface
does the pier abutment contain the lock or the key of the non-rigid connector?
the lock. the lock goes on the anterior retainer
tooth 33 is a pier abutment. which tooth has the slot?
a) 31
b) 32
c) 33
d) 34
c) 33
tooth 33 is a pier abutment. which tooth has the key?
a) 31
b) 32
c) 33
d) 34
d) 34
name 2 design options for tilted abutments and list a disadvantage for both
- non-rigid connector (adv: can change path of insertion, disad: have to prep more on PM)
- leave distal surface unpreped (disad: less rigidity)
2 “solutions” to limited restorative space
- adjust opposing occlusal plane
2. metal FDP
which canines make good pontics? maxilla or mandible?
mandible (compression forces). Maxilla canine has tension forces that lead to failure
list the steps for direct technique interim FDP
- impression
- prep teeth
- add material in matrix and set
list the steps for indirect technique interim FDP
- prep teeth
- impression
- model
- make temp on model
- mill restoration
list the steps for indirect-direct technique interim FDP
- impression
- model (can also do a wax-up)
- do conservative prep on model
- make PMMA temp
- prep teeth
- take hollowed PMMA temp and reline it with integrity
name 3 advantages of PMMA
- good polishability
- repairable
- durable
can you repair bis-acryl?
no
name an advantage of bis-acryl
resistance to abrasion
hygienic pontic: location
posterior mandible
hygienic pontic: pros
hygiene
hygienic pontic: cons
poor esthetics
hygienic pontic: contra-indication
little VDO, esthetic zone
hygienic pontic: material
metal
modified ridge flap: location
anterior teeth, esthetic zone
modified ridge flap: advantage
esthetic
modified ridge flap: material
metal-ceramic, ceramic, resin
ovate pontic: location
esthetic zone, high smile line
ovate pontic: advantage
superior esthetics, no food entrapment, easy to clean
ovate pontic: disadvantage
requires surgery, cannot place on ridge defects
ovate pontic: material
metal-ceramic, ceramic, resin
you are making an FPD for the posterior mandible. the patient has poor oral hygiene. what material do you select
a) metal
b) PFM
c) zirconia
d) resin
metal. pt has poor oral hygiene so they should have a hygienic pontic. these require metal
what material would you use for a long span FDP:
a) layered zirconia
b) monolithic zirconia
c) lithium disilicate
d) PFM
d) PFM [(could also use monolithic zirconia if it’s less than 5 unit FPD). don’t use ceramics bc they break due to flexion. layered zirconia is very weak and fractures]
why is an inverted smile pattern difficult to treat
it can indicate occlusal problems
what percent of the population has a complex smile pattern
2%
E method indicates that the incisal edges are __
in the lower third
retention for resin-bonded bridges comes from ___
resin cement
what is the main complication for resin-bonded bridges
de-bonding
studies show that the best design for resin-bonded bridges is __
1 wing designs (cantilever)
where does the resistance form come from for resin bonded bridges
proximally
risk of failure is most common in ___ bridges for resin-bonded bridges
mandibular anterior bridges (due to unseating from occlusal forces)
what bur do you use to polish metal
carbide
what bur do you use to polish porcelain
diamond
