Polycarbonate Temporary

Question 1

What is an example of polycarbonate crown?

Answer 1

Directa crown

Question 2

What is the method for fitting polycarbonate crown?

Answer 2

Select size - contact on proximal surface w/ adjacent teeth
If too long - trim crown (acrylic bur in straight hand piece)
Check reduction
Use self-cure resin to line the crown (snap) - fill voids at margin
Remove excess material and flash
Re-seat and check fit to margins

Question 3

How to use snap?

Answer 3

Place vaseline over prep, soft tissues and neighbouring teeth - prevent materials sticking
Place inside temp crown - manipulate to prevent void in incisal region
Gently seat
Excess material - manipulate at margins to avoid void
Excess must be removed at demi-stage
Further refinements can be made
Seat back onto prep

Question 4

How does snap come as a material?

Answer 4

Self-cure material - powder and liquid

Add liquid then add powder until not excess monomer present - mix till homogenous

Question 5

Why must excess material be removed from external surface of crown?

Answer 5

Cause plaque accumulation and gingival inflammation

Question 6

How to prevent temporary crowns looking too bulky?

Answer 6

Adjust on buccal aspect