Get specific with the "who" of your market (i.e. what kind of dentist? what is their specialty? whom do they serve? demographics and psychographics of both the dentist AND their patients?)
And specific with your offer to them. What are you selling? What are they buying? And why do they want it (according to THEM... not you)?
Get those factors right and they'll buy from you all day long.
Dentists will generally look at anything that increase the value of their time. There is a reason Invisalign has swept the globe. If you're selling something of lower value your cost-of-sale could be too high, so find somebody you can piggyback on, where your product complements what they have even if it means giving away half the revenue to them.
Firstly, be flexible on time. Make sure you work around their schedules. Lunchtime can be good for short meetings. Take time to understand then specifically and think about their key motivators. What puts more dentists in front of more patients? Everyone will be very different but maximizing billed time with patients should be a big driver for most. How does what you offer help them spend more time with patients?