Most seen problems when doing chamfer margins are undercuts and wide margins. Undercuts usually happen when the operator wants to refine or define the margins. However, one of the biggest mistake is that when doing so, they try to focus only on the margins. They lose their attention to the bur angulation, thus it will be slightly off from the long axis. The result will be a gouge or an undercut somewhere near the margins. Remember, you cannot work the wall without touching the chamfer and you cannot work the chamfer without touching the wall. They go hand in hand every single time.

So when you alter the margins, always make sure to to recalibrate your angulations parallel to the long axis of the tooth and do the margins and the axial walls all at the same time. You cannot work on a margin without touching the wall, and vice versa.

Also, you have to remember that margins have only 0.5mm in width which is half the size of the diameter of your chamfer bur. So when using only half of its size should sink into tooth. Some may loose focus and thus sinks the entire bur creating wide margins and enamel lips.

INSERT VIDEO HERE ( Michael’s video)