Concept Introduction

Composite preparations:

• conservative in nature
• rounded internal features
• Resistance and Retention Forms rely almost entirely on the bond of composite to tooth structure

Amalgam preparations:

• must be at least 2 mm deep to allow adequate thickness of material (Resistance Form)
• more distinct internal features
• internal walls must converge toward the occlusal (Retention Form) 

Cast gold preparations:

• similar to amalgam preparation except:
• internal walls must diverge toward the occlusal (Retention Form) 
• gold can be drawn thin at gold-tooth margin

Side view of an amalgam preparation being prepared by a drill:

Top view of a cast gold inlay and an amalgam preparation:

Application Phase

Go to the lab and first view the instructor demonstration. With the help of your lab manual, the text book, and your table instructor, practice preparing each of the preparation types described above (composite, amalgam, and cast gold preparations).

      Instructor Notes