You need to have a process that identifies patients that were NOT happy with your practice (yes, it happens more often than you think).
However, if you do cull out patients that you believe are not going to leave good reviews, keep in mind that Google frowns upon such behavior and calls it reviews gating.
There’s a pretty extensive article here – read that up.
Of course, you want to protect your reputation by gating reviews, but as the study shows, not gating reviews allows you to gather MORE reviews.
The penalties are also steep – so, be careful if you are planning on practicing review gating (I strongly discourage it).
Instead, here’s what you should do to avoid future headaches.