You can do this!I know how scary and intimidating and frightening this is because I've been dealing with it myself. You have to take this one step at a time. First step: Take a deep breath. Your choices are limited, but do you know for sure that none of the dentists you can see are nice, gentle, respectful people? You don't know for sure until you start taking steps.
Remember who is in charge, all the time. You are the mom. That doesn't change when you walk in the door of the dentist's office. Worst case scenario, if a dentist who told you he would be kind and gentle and respectful suddenly changes his mind, you can *and you will* pick up your child and walk out the door. Can you do that? Of course you can. It wouldn't be easy but you could do it for your child.
First, find out what your insurance (or whatever they're calling the "po' folks plan" these days!) will cover. Somehow my son has seen four different dentists in one month and my insurance covered each visit even though they all did the same thing. "Oh, yeah, that's a problem. Sorry, can't do that for you, try somewhere else."
Then get a list of dentists under your coverage and start calling. Write down what you want to say before you call; it won't help to ask about anything medical (like "Will he need fillings?") but you can say things like "I'll need to stay with my child at all times, is the dentist comfortable with that?" Also be sure they know how old he is and that he is very active, and that they are willing to deal with that; one of the dentists we went to was happy to do a cleaning on a four year old but nothing else. Nice little waste of time that was.
Pick one at random. Start with the closest! Now, all of the receptionists will tell you that the dentist will answer your questions at the initial appointment. So don't schedule anything until your questions are answered because she'll just brush you off.
When you get someone who sounds promising, go ahead and make an appointment. Then decide on a phrase about breastfeeding that you like and feel comfortable with and memorize it. Something like "Breastfeeding is not an issue I'm willing to discuss. How can YOU help my son?" If the topic comes up, repeat that phrase over and over, no matter they say, and they will eventually get the point and move on to the important part, which is helping your child.
Take a notepad and pen with you and write down everything the dentist recommends. Tell him your Gramma the dental tech wants to know or something, if he thinks it's weird. This will help you remember everything and it also lets them know you're serious about this. Don't schedule anything on the day of the first appointment, tell them you want to talk it over with your husband and you will call the next day and schedule. That way you can post here, do research online, and actually talk it over with your husband and know for sure what you want done.
If you get to the bottom of the list and no one on it is willing to work with you, call your insurance back and tell them that. You have a right to these services.
Remember, one step at a time. You can do this! You are the Momma Bear, the Momma Tiger, and you can advocate for and protect your child!