THE USE OF TOMOGRAPHY FOR DENTAL IMPLANT PLANNING

Objectives: To examine the use of tomography for dental implant planni ng. Methods: A questionnaire was sent to oral radiology clinics in Swe den and to implantology clinics in different parts of the world with q uestions on selection criteria and techniques for, and frequency of, p re-implant tomography. Differences between mean values were assessed b y t-test. A new method developed by the Swedish Radiation Protection I nstitute was used to assess radiation absorbed dose from CT. Results: Tomography was used by 93.4% of the clinics, but there was marked vari ation both between and within different clinical situations. It was pe rformed in all cases by 21% and the majority used it for the evaluatio n of the maxilla, the posterior mandible and in single implant cases. Small clinics (<100 patients per year) used tomography frequently and clinics in Sweden significantly more often than those in other countri es. The majority had changed their policy recently, using tomography m ore often. CT was used by 73% of respondents, mainly the small clinics . The majority of the large clinics (>500 patients per year) used conv entional tomography. The mean absorbed dose for CT scanning protocols was 65 mGy. The variation within and between different makes of CT was considerable. Conclusions: There are large variations in frequency of use of both conventional and computed tomography for dental implant p lanning by different clinics who also vary in the indications for thei r choice. A substantial factor influencing the technique chosen was it s availability rather than clinical need.