Hi Rachelle,
I say if you feel that he is not being honest with you then I would trust your gut feeling. Mother intuition is never usually wrong. I had to change dentists not too far back after being with the same dentist for over 15 years, because of the insurance thing just like you. And I was suckered into believing I needed a crown on one of my teeth, it was the worst thing I could have ever done!
I don't know of anything about Dr. Montoya but the dentist I went to was the same way super duper nice and I felt like he wasn't going to recommend any unnecessary treatments but unfortunetely I believe he did.
If your insurance takes Dr. Brian Almendinger of Chandler Pediatric Dental, I would get a second opinion from him. My boys go there and he has been wonderful he seems to take the conservative approach and usually recommends "watching" things for a couple of visits before he actually does anything. I have total confidence in him that he would never recommend anything unnecessary for either of my boys.
Good Luck!