Class II amalgam

Question 1

What is an embrasure?

Answer 1

V-shaped valleys between teeth that acts as a spillway for food to escape during chewing aiding the self-cleansing process

Question 2

What is the marginal ridge?

Answer 2

The meisial and distal edges of the tooth

Question 3

What needs to be considered about the restoration?

Answer 3

• Method of retention for material of choice
• Prevention of recurrent caries – elimination of microleakage
• Assist remineralisation of tooth tissue
• Longevity under occlusal load – fracture and wear resistance
• Protect tooth from mechanical failure
  aesthetics

Question 4

What is a class II restoration?

Answer 4

lesions occurring between posterior teeth only interproximally.

Question 5

What is the isthmus?

Answer 5

Narrow part between the two cusps (two proximal flares)

Question 6

What is a line angle?

Answer 6

the junction of two surfaces of the crown of a tooth, or of a tooth cavity

Question 7

When would you not extend the cavity?

Answer 7

If the proximal lesion is visible and access is good then the marginal ridge can be conserved

If the tooth is caries free occlusally it is NOT necessary to cut out the fissure.

Question 8

Class II prep start to finish?

Answer 8

1. initial cut made through marginal ridge to penetrate the caries and then widened bucco-lingually - diamond pear shaped or tungsten carbide bur
2. The proximal plate can be fractured off with a hand instrument (marginal trimmer) to avoid damage to the adjacent tooth (or you can use a matrix band)
3. removal of caries with excavator especially ADJ

Question 9

What is the size of the cavity determined by primarily?

Answer 9

Size of the carious lesion

Question 10

How can some adhesion be achieved with amalgam?

Answer 10

Use of lutting/bonding agents

Question 11

What should the cavo surface angle be at?

Answer 11

90 degrees to surface

Question 12

What is the depth of the cavity for amalgam?

Answer 12

2mm (1-1.5mm elsewhere)

Question 13

What do fractured margins need to be planed with?

Answer 13

Gingival margin trimmer in order to remove fragile enamel prisms which could break off and affect marginal seal

Question 14

How would you achieve a rounded gingival floor?

Answer 14

Pear shaped bur assists with shape

Question 15

Where are retention grooves placed?

Answer 15

placed 0.5mm deep to ADJ (dentine) gingivally fading away occlusally, rounded cross section. Directed laterally not pulpally

Question 16

What do matrix bands and wedges do?

Answer 16

Separate teeth interproximally to help with carving margins and creating contact points.

Substitutes for missing walls
Restricts extrusion of the amalgam and formation of overhands or ledges
Provides contour for proximal surface restoration

Question 17

How is the matrix band contoured?

Answer 17

Convex side of spoon excavator is used to impart a convex contour

Question 18

How would you condense the amalgam?

Answer 18

• Use amalgam pluggers/condensers
• adaptation of the amalgam to the walls of prep
• Eliminate voids
• Incremental placement of 1mm thickness

Question 19

What would you use to carve?

Answer 19

Wards carver e.g. No 2 or excavator