Fremgangsmåde til oprettelse af parodontalindeks, indretning til fremstilling deraf, program til fremstilling deraf, registreringsmedie til registrering deraf, fremgangsmåde til diagnosticering af parodontitis, indretning til diagnosticering deraf, program til diagnosticering deraf og registreringsmedie til registrering deraf

The sample attachment level (M) of each tooth is measured in a plurality of tooth samples taken per tooth type from a plurality of teeth extracted as unconservable teeth. A lost periodontal membrane area (S L ) is calculated based on the sample attachment level (M) and a total periodontal membrane area (S). A bite force coefficient (B) different according only to each tooth type, which reflects the bite force of each tooth, is found. The relation between the bite force coefficient (B) and a lost periodontal membrane area (S LB ) at the time of loss of each tooth is statistically processed for each tooth type, and a linear equation showing the relation between the bite force coefficient (B) and the lost periodontal membrane area (S LB ) at the time of loss of each tooth is prepared by use of the presence of a linear relation between both parameters. (Remaining periodontal membrane area (S SB )/total periodontal membrane area (S))X 100(%), where the remaining periodontal membrane area (S SB ) takes bite force into consideration and which is determined based on the lost periodontal membrane area (S LB ) at the time of loss of the tooth, is calculated as a periodontal index BPI representing the severity of progression of periodontitis.