If they didn't look at your email, you send a second email 24 hours later, or later if they didn't look at it you can send a text message to their numbers and still if they didn't look at any of it, you should call them and try to close the deal.
You can say something like "heh I am 'xy' from 'xyz' marketing agency and I just did an audit for you to show you how you could improve your ad spent, your conversation rate, make more sales by spending more or less money.
So I made a free video and it's already in your inbox, can you check it,"
And one important thing is you have to make sure that your audit has reached the right person, not a receptionist or someone.
So like if they say "yeah yeah! I got it." on the phone don't say okay, you should say something like "what I want you to do is to click on the email" and you don't say anything. Now they're gonna be like “what the hell!”. They're gonna think, and wait and as you are silent, they will flinch.
Now you are in control. After that you can say depending on the scenario. To the recipient you can say something like ”I guess that you are not the right person, so when should i call back, or who should i call back?”. Like this you need to make sure you have reached the right person.
What if the receptionist makes the decision to not deliver the message that you just say, to not deliver the email to the dentist. So you need to make sure that the dentist actually saw the email. And this is where you are basically 10x your chance of getting a lead or sale.