Sounds a little high. My sons' pediatric dentist in Keller charges $89 for a non-insurance visit. It is typical $95 ish, but if you pay up front at the time of visit, they give a small discount. Dr. MacAnthony if you want to try her out.
Quite a drive from Plano, but maybe you could call your dentist and find out if there are any ways to minimize the bill, like paying up front, getting on an in-house plan (some places you can pay $10 a month and it covers regular cleanings or with doctors, check ups. Kind of like thier own insurance plan).