[Evaluation of hygiene indices in studying the relations between oral hygiene and periodontitis based on epidemiologic studies].

The aim of the studies has been to determine the diagnostic clinical value of selected indices and to demonstrate their specific applicability under definite conditions. The study covered 184 subjects in two age groups: young persons aged 15-20 years, and adults being 20-45 years old. The oral hygiene was estimated by the following indices: OHI-S (Oral Hygiene Index-Simplified), Pl. I. (Plaque Index). C.P.I. (Cervical Plaque Index). The ++periodontium state was assessed by using the gingival index (G.I.). Periodontal index was defined by gingival index (G.I.), Russell's periodontal index (P.I.), as well as Kötzschke's periodontal index (K.I.). Sulcus fluid rate (S.F.R.) was also examined by Brill's method. The comparison of numerical values of the indices and statistical analysis of their cross correlation have shown that all of the indices having been involved in the study are of similar diagnostic value. However, C.P.I. appeared to be the best one, since the periodontitis indices most readily reacted to changes of its value. On the other hand, the oral hygiene index (O.H.I.-S) correlated more closely with inflammatory indices in adults, which suggests its particular applicability for examinations in this age group. (Pl. I.) may be used in young persons, in whom there are still no mineralized deposits of tartar. This index is easily determined, thus providing the possibility to evaluate the oral hygiene in quite a short time. Due to the fact that the quantitative measurements of sulcus fluid rate failed to reveal any statistically significant relation between the level of the sulcus fluid and periodontitis as well as oral hygiene in the youth, it has been ascertained that the sulcus rate measurement is of limited usefulness for clinically evaluating the state of parodontium, and may be resorted to in adult individuals only. It has also been disclosed that the resistance of parodontium to the action of pathogenic factors is greater in younger subjects.