Non-compete clauses are certainly not restricted to dental practices.
They usually stipulate a geographic distance from the associate wherin
you may not open your practice within a specified period of time.  The
distance and time period must be "reasonable".  It is possible that
standards for different industries of what is considered "reasonable"
may differ, but it seems that it should be possible to look at prior
case law and figure that out.  As this does not go to professional
competence etc. in which a specific dental knowledge may be important,
it seems to me that any good business contract attorney should be able
to advise you.

Steve