radiation exposure from x-rays

I take my two kids, ages four and six, to the pediatric dentist for check-ups every six months. Without fail, they take x-rays every single time. This concerns me for two reasons: 1) the amount of radiation they’re being exposed to, and 2) I’m paying for two sets of x-rays a year out-of-pocket because our insurance only covers x-rays once … We can’t afford x-rays every six months