8.1 Acess incisors, canines and premolars

Question 1

What are the principles of access cavity design?

Answer 1

• allow removal of roof of pulp chamber and pulp horns
• allow direct vision of pulpal floor and canal orifices
• avoid damage to pulpal floor or perforation
• allow straight-line access into canals
• provide retention for placement of a temporary restoration between visits
• conserve as much tooth structure as possible (overzealous access cavities can render tooth not restorable)

Question 2

When inexperienced, is it better to cut most of the access cavity with or without a rubber dam in place?

Answer 2

without - so you do not lose your orientation and risk perforation - especially if the tooth is crowned, tilted, rotated or the pulp chamber calcified

Question 3

what direction do most incisor perforations happen?

Answer 3

labially

Question 4

what type of bur is used to cut the initial outline form of an access cavity?

Answer 4

a small round diamond bur is used to cut the initial outline form, 1mm deep into enamel

Question 5

what type of bur is used to deepen the access towards the roof of the pulp chamber and penetrate the roof while avoiding peroration?

Answer 5

a long fissure diamond bur

Question 6

what bur would you use to cut through a metal crown?

Answer 6

tungsten carbide bur

Question 7

what bur would you use to cut through a metal ceramic crown?

Answer 7

you would cut through the porcelain part with a diamond bur and then the metal part with the tungsten carbide bur

Question 8

what type of bur would you use to penetrate through the roof of the pulp chamber?

Answer 8

latch grip “slow speed bur”

Question 9

what is a long shank latch grip bur used for?

Answer 9

• removal of the roof of the pulp chamber
• removal of palatal shelf in upper anterior teeth
• careful exploration of pulpal floor to uncover narrow canal orifices

Question 10

what bur is used after completion of access to flare, flatten and finish axial walls?

Answer 10

non-end cutting high speed bur
- either diamond tapered or tungsten carbide tapered

Question 11

what shape should you cut for a maxillary central incisor

Answer 11

triangular

Question 12

what shape should you cut for a maxillary lateral incisor?

Answer 12

triangular (but narrower than central)

Question 13

what shape should you cut for a maxillary/mandibular canine?

Answer 13

ovoid

Question 13

what depth should the initial outline of an access cavity cut into enamel?

Answer 13

1mm into enamel

Question 14

in what direction should you cut to enlarge the access cavity?

Answer 14

an outward motion on the dentinal walls with a brushing motion to removal all dentine overhangs

Question 15

the initial approach to the access cavity should be at what angle?

Answer 15

45 degrees