Quantifying Mandibular Bone Remodelling Underneath Implant-retained Overdenture

Objective: To develop a new method of quantifying mandibular bone remodeling (height, area and volume) associated with the wearing of implant-retained overdenture opposing maxillary complete denture over a period of one year by cone-beam computerized tomography (CBCT) scanner and Mimics program. Materials and Methods: This prospective study investigated the bone remodeling of 10 patients. CBCT images were acquired prior to the treatment and after one year period of wearing overdenture retained by 2 implants. The three-dimensional models of the mandible were generated based on these CBCT images using Mimics program. The models were superimposed to identify the areas of bone resorption and to measure the changes in the residual ridge height, area and volume in the posterior mandible. The posterior mandible on each side from distal to the implants placed in the canine up to the retromolar pad area was divided into 6 sections of 5 mm thickness each. Results: Out of the ten patients, eight patients demonstrated a decrease in bone height, area and volume. The average decrease over a period of one year was 0.48 mm in bone height, 138 mm2 in area and 229 mm3 in volume. Two patients had a minimal increase in bone height, area and volume. The increase was 0.11 mm in height, 98 mm2 in area and 132 mm3 in volume. There was no significant difference in the mean changes of bone height, area or volume between the six different areas of the posterior mandible studied. Conclusion: This new method allows precise identifying and quantifying the areas of mandibular bone undergoing remodeling a year after wearing implant-retained overdenture in an in vivo fashion.