autumn midterm; class II amalgam criteria

Question 1

what should clearance be on a class II

Answer 1

.25 to .5 mm

for lingual buccal and gingival

Question 2

how do you measure clearance of a class II

Answer 2

face exporer upwards, slide along length of wall. 1-2 mm of tip sould extend into box area. explorer can be tight but shouldnt click. UX means teeth touching and OX means #1 fits through..

Question 3

what is wrong with exit angles less than 90 degrees

Answer 3

UNSUPPORTED ENAMEL RODS

-reduces fracture resistance of the tooth margin

Question 4

what is wrong with over 90 degree exit angles

Answer 4

• REDUCES RETENTION FORM
• reduces fracture resistance of the restoration margin
• reduces convenience for placement of material.

Question 5

what are the criteria for gingival floor of a class II

Answer 5

1.5 mm depth, flat floor, perpendicular to long axis of the tooth..