Bridges

Question 1

what factors influence the success of adhesive bridgework (4)

Answer 1

quality of bonding surface
design of retainer
design of pontic
occlusal management

Question 2

what pontic design should be used posteriorly for a bridge

Answer 2

dome shape

Question 2

what are the two design aspects of a retainer for an adhesive bridge

Answer 2

0.5mm lingual and interproximal areas
0.1mm occlusal areas

Question 3

what is the pontic design that should be used anteriorly for a bridge

Answer 3

modified ridge lap

Question 4

how do conventional indirect restorations stay in place

Answer 4

resistance from opposing walls of the preparation prevent displacement
for maximum retention these walls should be parallel
however most walls will have 7-9 degree taper to long axis of the tooth

Question 5

what are four types of conventional bridges

Answer 5

fixed fixed
cantilever
fixed moveable
spring cantilever

Question 6

how should the abutment teeth at either side of the pontic be prepared with regards to their walls

Answer 6

the walls should be parallel

Question 7

how may we overcome the problem of providing a bridge to teeth that are tilted

Answer 7

retainers with separate parts of insertion
eg - moveable connector

Question 8

what are unfavourable tooth contacts

Answer 8

on cuspal inclines
no contact at all

Question 9

what may contacts on cuspal inclines lead to

Answer 9

lateral forces being applied to teeth

Question 10

what are the 5 properties of occlusal forces

Answer 10

magnitude
velocity
frequency
duration
direction

Question 11

what are the three types of occlusal guidance

Answer 11

canine
group function
balanced articulation - complete dentures only

Question 12

why is canine guidance preferred

Answer 12

simple to produce guiding contacts on anterior restorations
posterior teeth are restorations are protected

Question 13

what are facebows used for

Answer 13

mounting upper casts only
transfers the relationship between maxillary teeth and axis of rotation from patient to articulator

Question 14

what makes up the assessment to see if a patient is a suitable candidate for bridgework

Answer 14

patient preference
age - not too old/young
attitude to dentistry
medical conditions
diet/ smoking/ cost
dentist skill
consent

Question 15

what are adhesive bridges

Answer 15

those retained by metal wing(s) which are bonded onto minimally prepped enamel

Question 16

how do you improve bridge retention

Answer 16

maximise available bonding surface area
sandblast fitting surface of wing
cutting notches/ grooves and locating margins
incorporate rest seats

Question 17

why is only one abutment preferred for adhesive bridges

Answer 17

oral hygiene
divergent guide paths

Question 18

what are the two main types of bridges

Answer 18

conventional (crowns on abutment teeth)
adhesive (wings)

Question 19

what are two types of bridge designs (can be used for either conventional or adhesive)

Answer 19

fixed fixed
cantilever

Question 20

when would a fixed moveable bridge be used

Answer 20

when you cannot achieve a common path of insertion

Question 21

what is a spring cantilever bridge and when would it be used

Answer 21

on pontic attached to end of metal arm that runs across the palate to rigid connector on palatal side
used when the anterior teeth are unrestored and there is a suitable posterior tooth

Question 22

what are the five types of pontic connector designs

Answer 22

wash through
dome
modified ridge lap
ridge lap
ovate

Question 23

what is LAVA 3M ESPE

Answer 23

3-4 unit bridge milled zirconium oxide

Question 24

what should be used to cement metal or metal ceramic conventional bridges

Answer 24

GI or RMGIC luting cement (aquacem or relyX)

Question 25

what should be used to cement adhesive bridgework

Answer 25

panavia - anaerobic dual cure resin cement

Question 26

what should be used to cement all ceramic bridgework

Answer 26

NEXUS - dual cure resin cement

Question 27

why should distal cantilevers be avoided

Answer 27

concerns that occlusal forces on pontic will produce leverage forces on abutment tooth and cause it to tilt

Question 28

what is combination syndrome

Answer 28

where a denture opposes natural dentition and the forces exerted cause increased resorption of the alveolar ridge