How does an undercut impact an inlay preparation?

Impedes insertion: We try to avoid undercuts during the preparation of an inlay or onlay as this can become problematic for the insertion of the inlay or onlay once ready to be cemented in. However, a good dental lab can compensate for this in the fabrication of the inlay or onlay.

Inlay preparation: During the preparation needless loss of tooth structure to eliminate gross undercut areas is needed to be avoided. Directly placed composite or light cured glass ionomer restorative can eliminate the undercut areas and create a conducive cavity form for insertion.