What is the lifetime value of an average Dental patient?  

Are there any numbers or statistics that take into account...
everything from hygiene appointments to restorative and cosmetic
dentistry that is performed on each patient during the course of their
life.  (Say at least 25 years.)  I am trying to convince dentists with
whom I consult, not to just focus on one treatment at a time, but
rather to view each patient in light of their lifetime value.

Also, I am looking for statified statistics that show average dental
treatments performed for each patient per year, as well as what are
the average amount of treatments performed each month or year.  I want
a reference point by which each dentist can measure themselves
according to all dentists in the entire USA.  Also, I want to be able
to use what research you find to see how much of the Lifetime value
(number of treatments) a dentist is losing when they lose a patient
after only a few years.  My goal is to use the info to convince them
in my seminars or consults, that they should not be shortsighted when
it comes to keeping patients happy and to be patient while waiting
until patients are ready for treatment - during the course of their
life.