I too am a dentist and have used P&S cameras in the past to document treatment procedures. My recommendation is don't waste time and money on a P&S camera. None of them will give you the professional looking result you'd want to show to your colleagues for study clubs or seminars. None of them have the necessary depth of field to give you clear images front and back. What I mean by that is if you focus on tooth #8, then #4 will be out of focus.
I recommend you save up and get a ready-packaged unit from Lester-Dyne or save a lot of money by getting what I suggest below. You do not need the latest and the best from Nikon or Canon. A refurbished unit such as previous generation Nikon D5000 with warranty from a reputable dealer can be had for $330. I recommend a dedicated macro lens specifically designed for the likes of your task (intra-oral images) and can do 1:1 ratio: new, it costs $480. A ring flash is a must item also; non-Nikon one can be had for $90. D5000 also does videos too. Total cost of around $900. I know it's much more than the cost of a Coolpix but the result you can achieve will be so much better than with a P&S camera. And you can use this set-up for many, many years. If your camera ever wears out, you can just get another camera body later and use the same lens. Come on, one high quality handpiece costs more than $900 and you'd be lucky to get a year out of them without changing out the turbine.
Using a P&S camera is akin to using Dremel tool on your patient because you "can't" afford a high speed.
http://www.bhphotovideo.com/c/product/732693-REG/Vivitar_DF586NIK_DF_586_Dedicated_Macro_Ring.html
http://www.bhphotovideo.com/c/product/731093-REF/Nikon_25452B_D5000_Digital_SLR_Camera.html
http://www.bhphotovideo.com/bnh/controller/home?O=&sku=656971&Q=&is=GREY&A=details
