Lab Class II prep Question?

[mmssdental]

Does a class II prep for composite need complete clearance from the adjacent tooth? This was for class II MO on tooth #14.

On CDCA does a contact point btw axial wall and gingival floor result in 0 if not 90 degrees and a bit rounded?

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[HabituallyPlacid]

I think you only need to make buccal and lingual clearance for amalgam restorations—class II preps (MODs, MOs, slot boxes, etc.) for composite resins can have clearance as well, but it’s not as imperative for long term success. The axial wall should make a near 90-degree with the gingival floor, while the pulpal floor/axial wall ledge should be a bit more rounded to prevent sharp angles that could fracture the restoration (specifically amalgams).

 

[mmssdental]

I think you only need to make buccal and lingual clearance for amalgam restorations—class II preps (MODs, MOs, slot boxes, etc.) for composite resins can have clearance as well, but it’s not as imperative for long term success. The axial wall should make a near 90-degree with the gingival floor, while the pulpal floor/axial wall ledge should be a bit more rounded to prevent sharp angles that could fracture the restoration (specifically amalgams).

Thank you!