Access Cavity Preparation - Incisors, Canines, Premolars

Question 1

Should rubber dam be used when cutting access cavities?

Answer 1

WITHOUT rubber dam if inexperienced (do not lose orientation/ perforate).

• especially if tooth tilted, rotated, crowned or pulp chamber calcified?

Question 2

What product is used to fill ROOT perforations of RCTd teeth?

Answer 2

MTA.

Question 3

What are the 4 burs needed to create an access cavity?

Answer 3

1. high-speed small round diamond to cut initial outline (1mm into enamel).
2. high-speed long-fissure to deepen access towards roof + penetrate roof.
3. slow speed long shank - remove pulpal roof + uncover canal orifices + remove paltal shelf (anterior teeth upper).
4. high speed non-end cutting - flare and finish axial walls.

Question 4

How deep into enamel is the outline of an access?

Answer 4

1mm deep using round high speed bur.

Question 5

What is the palatal shelf?

Answer 5

“Overhang/shelf” created when accessing upper anterior teeth with the high speed long fissure bur.

Question 6

What burs should be used to access through crowns?

Answer 6

• Metal crowns: tungsten carbide.
• Metal ceramic crowns: tungsten + high speed round bur.
• Ceramic crowns: Komet ZR diamond, SS white great white z.

Question 7

What is the access cavity shape for a maxillary central incisor?

Answer 7

Triangular

Question 8

What is the access cavity shape for a maxillary lateral incisor?

Answer 8

Triangular

Question 9

What is the access cavity shape for a maxillary canine?

Answer 9

Ovoid

Question 10

What are the 4 steps to access cavity design?

Answer 10

1. Initial outline (high speed round bur)
2. Penetration (high speed long fissure bur)
3. Enlargement (slow speed long shank round bur)
4. Finishing and flaring (high speed non end cutting bur)

Question 11

What stage is the long shank round bur used for and how is it used?

Answer 11

Used for enlargement
- brush against dentinal walls, cutting on UPWARD STROKE to remove DENTINAL OVERHANGS/ PALATAL SHELF + PULP ROOF —> allow straight access

Question 12

What is the access cavity process for maxillary incisors and canines?

Answer 12

1. Use a round bur for INITIAL OUTLINE AT 45 DEGREES TO PALATAL SURFACE, 1mm depth.
2. Change to fissure but and proceed down the long axis of the tooth.
3. Use slow speed round long shank to remove pulpal roof and palatal shelf to allow straight access.
4. Use non end cutting bur.

Question 13

What is the access cavity shape for premolars?

Answer 13

Oval

Question 14

How many root canals do upper premolars have?

Answer 14

Maxillary 1st premolar: 2 canals one buccal one palatal
Maxillary 2nd premolar: same as above OR one canal centrally placed in 50% of cases.

Question 15

What must we be aware of when accessing a mandibular first premolar?

Answer 15

Crown is titled towards LINGUAL - take care not to perforate.

Question 16

Where is the pulp chamber of a manibilar first premolar located?

Answer 16

Under the buccal cusp.

Question 17

What is a round high speed bur used for in endo prep?

Answer 17

Cutting access cavity, 1mm into dentine.

Question 18

What is a latch grip/ slow speed long shank rosehead bur used for in endo prep?

Answer 18

• Remove pulpal roof.
• Uncover canal orifices.
• Remove palatal shelf.

Question 19

What is a long fissure high speed bur used for in endo prep?

Answer 19

• Deepen access towards pulp chamber roof.
• Penetrate pulp chamber roof.

Question 20

What is a non-end cutting bur used for in endo prep?

Answer 20

Flare, flatten and finish axial walls.