Assessment of periodontitis grade in epidemiological studies using interdental attachment loss instead of radiographic bone loss

Aim: Comparison of grading according to radiographic bone loss (BL) or according to interdental clinical attachment loss (CAL).

Materials and methods: In 100 periodontitis patients at the Department of Periodontology of Goethe-University Frankfurt, Germany, periodontitis grade was assigned by (i) indirect evidence using BL at the most affected tooth divided by root length and (ii) CAL at the most affected tooth divided by root length of the respective tooth type according to root length in German and Swedish cohorts. The resulting quotients were divided by age.

Results: Patients (age: 53.5 ± 10.4 years; 57 females; 16 smokers; no diabetes; stage: 78 III, 22 IV) were by either method assigned to grade B or C (BL: 35 B, 65 C; CAL [German]: 23 B, 77 C; [Swedish]: 29 B, 71 C). Using root length (German cohort), agreement was 76% (kappa: 0.427; fair to good/moderate agreement) and 72% (Swedish cohort; kappa: 0.359; poor/fair agreement). Molars were most frequently chosen (BL: 64%; CAL: 71%).

Conclusions: Assignment of periodontitis grade by indirect evidence using BL or CAL using standard root length of the German cohort showed fair to good/moderate agreement. Thus, grade assignment by CAL may be used in epidemiologic studies where radiographs are not available.