Sales Training 2014 - Dentistry

529

Chapter 27 * Casting Procedures

B

A

C

D

E

Figure 27.9 Inspection and finishing of the casting. (A) Inner surface (which will be in contact with the prepared surface of the tooth) should be carefully examined under higher magnification and illumination for any discrep- ancy. (B) Tiny air bubbles in the investment create very minute nodules (yellow arrows) on the inner surface, which interfere with the fitting of the casting. A single nodule may be carefully removed without much distor- tion of the inner fit. Presence of multiple nodules may necessitate the repeat of the casting. (C) Improper coating of the inner surface of a narrow wax pattern with investment material may result in entrapment of large volume of air. This will result in a large nodule (yellow arrow) of metal blocking the whole inner surface; this nodule is extremely difficult to remove and in this case, the casting will have to be repeated. (D) Accuracy of the fit is then checked on the die first and (E) then the die is placed in the cast and checked again.

Ch_27_DM.indd 529

5/13/2013 2:46:10 PM