Hello, I'm a marketer and strategist by trade. One of the best in Arizona, where I reside.
I can guarantee you that a fundamental reason is that you are calling and talking more about you instead of them. Do your homework on dental services. Aim for one genuine friendly relationship so that you tap into one dentist for pain points and feedback before talking or aiming your efforts (whatever they might be after all) at other dental offices. Once you know what they need, what they want, what they aim for then you can change the conversation to how you can be of value to them.

Another thing is that you don't call and introduce yourself and ask for a partnership in the first same call. Nurture a relationship, address your goals and purpose of the relationship but don't press for a "trial" start by maybe you sending them clients.

Also, read on blue ocean strategies. I have actually helped massage companies increase their market share with this sole methodology. Think out side the box and also from their perspective. :) #unthink