Bridgework 2

Question 1

what are the advantages of conventional fixed-fixed bridges

Answer 1

robust design
maximum retention and strength
abutment teeth splinted together
can be used in longer spans
laboratory construction straightforward

Question 2

what are the disadvantages of conventional fixed-fixed bridges

Answer 2

preparation difficult
preparation must be minimally tapered
common path of insertion for abutments
removal of tooth tissue

Question 3

what are the advantages of a cantilever

Answer 3

conservative design
lab construction straightforward
no need to ensure parallel teeth

Question 4

what are the disadvantages of a cantilever

Answer 4

short span only
rigid to avoid distortion
mesial cantilever preferred

Question 5

what is the issue when teeth are not parallel

Answer 5

there are multiple paths of insertion (and therefore displacement)

Question 6

what is a fixed moveable bridge

Answer 6

2 separate parts (with 2 different paths of insertion) which slot together when put together

Question 7

what are the advantages of a fixed moveable bridge

Answer 7

preparations dont require a common path of insertion
each preparation designed to be retentive independent of others
more conservative of tooth tissue
allows minor tooth movement
may be cemented in two parts

Question 8

what are the disadvantages of a fixed moveable bridge

Answer 8

length of span limited
laboratory construction more complicated
possible difficulty in cleaning beneath moveable joint
cant construct provisional bridge

Question 9

what is a spring cantilever bridge

Answer 9

one pontic attached to the end of a metal arm which runs across the palate to a rigid connector on the palatal side of a retainer

Question 10

what are the advantages of a spring cantilever brdige

Answer 10

spacing present between upper incisors
where adjacent teeth are unrestored
where posterior provides a more suitable abutment

Question 11

what are the disadvantages of a spring cantilever bridge

Answer 11

can only be used to replace upper incisors
difficult to clean beneath palatal connector
may irritate the palatal mucosa
difficult to control movement of pontic due to springiness of metal arm and displacement of palatal soft tissues

Question 12

what do you consider when evaluating an abutment tooth

Answer 12

must be able to withstand the forces previously directed to missing teeth
supporting tissues should be healthy and free of inflammation
crown to root ratio should be 2:3

Question 13

what is the minimum crown to root ratio

Answer 13

1:1