The longevity of an osseointegrated implant is directly affected by the maintenance of its osseous anchorage. Progressive marginal bone loss would be detrimental to its survival. This article proposes a new radiographic index for use in the radiographic assessment of peri-implant marginal bone levels. The index scores range from 0 to 6 and denote marginal bone loss in percentages relative to the implant body length measured from its coronal-most margin in an apical direction. The proposed index should be of significance in: (1) use of short implants (7 to 10 mm); (2) evaluation of implants functioning in areas of low bone density (types 3 and 4); (3) prognosis and treatment of ailing/failing implants; (4) follow-up of implants placed in extraction sites; and (5) correlation of crown-to-implant ratio with marginal bone loss.
Keywords: marginal bone level, osseointegration, radiographic index