Note the CONVEX curvature of the axial wall to preserve tooth structure.
OUTLINE & RESISTANCE
The BROWN line indicates removal of enamel decalcification down to sound enamel. The axial depth is just beyond the DEJ to insure complete identification and removal of dentinal caries. Since there are limited functional forces in this area, a minimum axial depth of 0.75 mm provides sufficient resistance and retention form for thickness of the restorative material.
RETENTION
The GREEN lines indicate the 45-degree bevel placed on all ENAMEL cavosurface margins to expose enamel rod ends for etching and bonding. There is no bevel on DENTIN cavosurface margins. A gingival retention groove is placed to enhance retention at the gingival portion since dentin bonding is not as reliable as enamel bonding. |
