1 The average cost for cavity repair is $80 to $200 per tooth, depending on the size of your tooth cavity. 2  Cavities that have a white resin filling are going to cost more than a filling that is silver.3  Generally, the white filling is going to be 30% to 40% more than the silver filling. A dental x-ray is usually needed prior to cavity repair. 2  Dental x-rays can cost anywhere from $60 to $180. 3  In extreme cases, the dentist may have to completely remove the tooth. 4  To receive a replacement, something such as a veneer may be required in order to replace the older tooth.