The first number in the range is one of the lowest rates charged for that particular service in that State and the second number is one of the highest rates charged for a particular service. In California, the average costs for dental care: A full set of x-rays: $101 to $147. An adult cleaning and exam: $70 to $102. A child’s cleaning and exam: $49 to $71. Child’s fluoride treatment: $42 to $61.