Lecture 3

Question 1

contraindications of FPDs

Answer 1

excessive edentulous span

weak abutment teeth

Question 2

ante’s law

Answer 2

pericemental area of abutment teeth > pericemental area of edentulous spaces

if roots of abutments are absorbed you cannot do this

Question 3

effect of length on deflection

Answer 3

deflection = length ^3

length is edentulous spaces

Question 4

effect of connector height on deflection

Answer 4

deflection = 1/Height ^3

ex: 1/2 connector height is 8X deflection
inc connector thickness to decrease deflection

Question 5

what is the optimum crown to root ratio for FPDs

Answer 5

2/3

1/1 will work but it is minimum

Question 6

root suface area is important for what?

Answer 6

periodontal support

curved roots are better than straight
divergent roots are better than convergent

Question 7

which teeth are the worst to be abutments due to their low root surface area?

Answer 7

lateral incisors

Question 8

what are the options if there are POW complications

Answer 8

• ortho
• intracoronal attachments (lock and key)
• removal of offending proximal contact of adj tooth

Question 9

pontic that resembled a saddle that is esthetic bc it simulates the contours and emergence profile of missing tooth

Answer 9

ridge lap pontic

not recommended bc difficult to clean the mucosal surface —- leads to soft tissue ulceration

Question 10

pontic with horrible esthetics (only used in posterior)

has easy plaque control but can’t be use in maxillary arch

Answer 10

hygenic pontic

1-2mm distance btw pontic and mucosal surface

Question 11

pontic that resembles the hygienic but has an even wider space

Answer 11

modified hygienic pontic

Question 12

most common pontic design
can be used in anterior and maxillary
esthetic and cleanible

Answer 12

modified ridge lap pontic

floss should go through it

Question 13

when should metal occlusals be used?

Answer 13

with pts with bruxing, clenching or grinding

Question 14

pontic used on knife edge ridges

Answer 14

bullet pontic

used on mandibular molars without esthetic requirements
*hygienic should be used on broad ridges

Question 15

pontic similar to bullet pontic but is not similarly used

Answer 15

ovate pontic

challenge for pts to clean underneath

Question 16

pontic with only one abutment

Answer 16

cantilevered pontic

pontic should NEVER be distal

Question 17

where are cantilevered pontics used?

Answer 17

for lateral incisors with canines as the abutment

this avoids intact central incisor prep

Question 18

abutment that is the middle of a 5 unit FPD

Answer 18

pier abutment

acts as fulcrum during function
the retainers need to be retentive