CC/NUMBER 45
This Week’s Citation Classic NOVEMBER 5, 1979
Russell A L. A system of classification and scoring for prevalence surveys of periodontal
disease. J. Dental Res. 35:350-9, 1956.
[National Inst. Dental Res., National Institutes of Health, Bethesda, MD]
A scoring method is proposed for the study a function of the ages of the persons studied.
of chronic destructive periodontal disease in At younger ages right skewness is severe,
human populations. Individual scores are evolving into a roughly square pattern in the
increased as the disease progresses through middle ages, and finally into extreme left
a syndrome ending with loss of function of skewness in persons over the age of 40 or 50
the dentition. Few instruments or adjuncts years. No one transformation seemed
are required. Emphasis is on examiner appropriate over the entire range. Average
comparability. [The SCI ® indicates that this scores for small groups were normally
paper has been cited over 235 times since distributed, and some of my later findings
1961.] were reported on this basis. Weighting of
scores was manipulated experimentally to
A.L. Russell reflect the gravity of the condition as judged
1720 Palomar Drive by clinical periodontologists, and to yield
Ann Arbor, Ml 48103 straightline curves with age for some scores
of thousands of persons aged up through 84
August 9, 1979 years. This last permitted comparison of the
status of two or more groups differing in
“The classic epidemiological approach to mean age.
a disease of unknown etiology involves the “The Index has since been recommended
division of a population into groups with for epidemiological research by the World
and without the disease so that the Health Organization and other evaluatory
determining factors in their ways of life can bodies.
be identified. But, some degree of chronic “In 1956 there were as many concepts of
destructive periodontal disease affects the etiology of chronic destructive
virtually every adult. Hence, it was periodontal disease as there were professors
necessary to develop a strategy of separating of periodontics. Since that time the
groups with the greater from groups with the consensus has developed that the disease is
lesser degree of involvement before the due basically to bacterial activity as
disease could be studied epidemiologically. modified by host defensive factors. This is
The Periodontal Index was devised for this consistent with my findings in a series of
purpose. It was developed over a period of nutrition surveys in world areas where dental
ten years prior to publication care was virtually nonexistent and oral
“During its gestation it was trimmed from a hygiene practices were ineffective 1 — in
30-minute procedure requiring an extensive short, where there was little interference
armamentarium to a one-minute inspection with the natural progression of the disease.
conducted mostly with a dental mirror. This My data, since corroborated,2 showed no
was done through elimination of items which consistent association with diet, or nutrition,
proved to be extraneous, or were or ethnicity, or a host of other factors once
irreversible, and by elimination or deem- considered etiologic. The factors that
phasis of items on which examiners found it emerged invariably as important were
difficult to agree. chronological age and evidence of past or
“There were difficulties with statistical present oral infection.”
management. Distribution of Index values is
1. Russell A L. World epidemiology and oral health. Environmental variables in oral disease. (Kreshover S
J & McClure F J, eds.) Washington. DC: American Association for the Advancement of Science.
1966. p. 21-39.
2. Ramfjord S P, Emslie R D, Greene J C, Held A J & Waerhaug J. Epidemiological studies of
periodontal diseases. Amer. J. Pub. Health 58:1713-22. 1968.
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