Data from the

NATIONAL HEALTH SURVEY

Oral Hygiene

Among Youths 12-17 Years

United States

Estimates of the Simplified Oral Hygiene Index (OHI-S) for

noninstitutionalized youths aged 12-17 years in the United

States, by age, sex, race, family income, education of head of

household, and geographic region, and a correlation analysis

of the interrelation of oral hygiene, periodontal disease, and

selected demographic characteristics.

DHEW Publication No. (HRA) 76-1633

US. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

Public Health Service

Series 11

Numk 151

Health Resources Administration

National Center for Health Statistics

Rockville, Md. September 1975
.—

/’

Library of Congress Cataloging in Publication Data

Sanchez, Marcus J

Oral hygiene among youths 12-17 years, United States.

(Vital and health statistics: series 11. Data from the National Health Survey; no. 151)

(DHEW publication; no. (HRA) 76-1633)

Bibliography: p.

Supt. of Dots. no.: HE 20.6209:11/151

1. Youth–Dental cme–United States–St atistics. 2. Teeth–Care and hygiene. 3. Dental

surveys-United States. 4. Dental public health-United States. I. Title. II. Series: United

States. National Center for Health Statistics. Vital and health statistics. Series 11: Data from

the National Health Survey. Data from the health examination survey; no. 151. III. Series:

United States. Dept. of Health, Education, and Welfare. DHEW publication (HRA);

76-1633. [DNLM: 1. Dental health surveys-In adolescence–U.S. W2 AN148vk no. 151 ]

RA407.3.A347 no. 151 [RK55.C5]312’0973S 76-619041

ISBN 0-8406 -0040-2 [617.6’01]

For sale by the Superintendent of Documents, U.S. Government Printing 05ce, Washington, D.C. 20402- Price 85 cents

—.
NATIONAL CENTER FOR HEALTH STATISTICS

EDWARD B, PERRIN, Ph. D., Director

PHILIP S. LAWRENCE, SC,D., Deputy Director

GAIL F. FISHER, Associate Director for the Cooperative Health Statistics System

ELIJAH L, WHITE, Associate Director for Data Systems

IWAO M. MORIYAMA, Ph.D., Associate Director for International Statistics

EDWARD E. MINTY, Associate Director for Management

ROBERT A, ISRAEL, Associate Director for Operations

QU13NTINR. REMEIN,Associate Director for Program Development

ALICE HAYWOOD, Information Officer

DIVISION OF HEALTH EXAMINATION STATISTICS

ARTHUR J. McDOWELL, Director

JEAN-PIERRE HABICHT, M.D., Ph.D., M.P.H., Special Assistant to Director

JAMES E. KELLY, Chief NCHS Dental Adviser

JEAN ROBERTS, Chiefi Medical Statistics Branch

ROBERT S. MURPHY, chief Survey P&mning and Deve~opment Branch

COOPERATION OF THE BUREAU OF THE CENSUS

In accordance with specifications established by the Nationaf Health Survey, the Bureau of the

Census, under a contractual agreement, participated in the design and selection of the sample,

and c,mied out the fiist stage of the field interviewing and certain parts of the statistical

processing for the Heafth Examination Survey.

VitaI and Health Statistics-Series 11-No. 151

DHEW Publication No. (HRA) 76-1633

Library of Congress Catalog Card Number 76-619041
CONTENTS

Page

Introduction ----------------------------------------------------------

Background (Source of Data)-----------------------------------------

The Examination ---------------------------------------------------

Nonresponse -------------------------------------------------------

Limitations of Data -------------------------------------------------

Simplified Oral Hygiene Index (OHI-S)-----------------------------------

Oral Hygiene Findings ----------------------------------------------

Age---------------------------------------------------------------

sex ---------------------------------------------------------------

Race --------------------------------------------------------------

Expected Value (Age-Control)----------------------------------------

Family Income -----------------------------------------------------

Education of Parent -------------------------------------------------

Geographic Region --------------------------------------------------

Discussion -----------------------------------------------------------

Interrelationof OHI-S and Selected Demographic Variables --------------

Interrelation of PI, OHI-S, and Selected Demographic Variables ----------

PeriodontalIndex (PI)-----------------------------------------------

OHI-S Findings From PreviousHES Reports ------------------------------

Summary -------------------------------------------------------------

References -----------------------------------------------------------

List of DetailedTables -------------------------------------------------

Appendix I. Statistical Notes -----------------------------------------

The Survey Design --------------------------------------------------

Reliability ---------------------------------------------------------

Sampling and Measurement Error ------------------------------------

Tests of Significance ------------------------------------------------

Small Numbers -----------------------------------------------------

Expected Value -----------------------------------------------------

Appendix II. Demographic and Socioeconomic Terms --------------------

Appendix III. The DentalExamination -----------------------------------

The Periodontal Index (PI)-------------------------------------------

The Simplified Oral Hygiene Index(OHI-S)-----------------------------

Training of Examiners ----------------------------------------------

OHI-SScores byExaminer -------------------------------------------

1

1

1

2

2

2

2

3

4

4

5

5

7

10

11

11

12

12

13

14

16

17

28

28

29

29

31

31

31

32

33

33

33

34

35

iii
SYMBOLS

Data not available ---------------------------------------- ---

Category not applicable ------------------------------- . . .

Quantity zero ---------------------------------------------- -

Quantity more than Obut less than 0.05 ----- 0.0

Figure does not meet standards of

reliability or precision ------------------------------ *

iv
ORAL HYGIENE

AMONG YOUTHS 12-17 YEARS

Marcus J. Sanchez, Division of Health Examination Statistics

INTRODUCTION

This report presents estimates of the oral

hygiene status of U.S. youths aged 12-17 years,

according to race, sex, age, and other selected

demographic characteristics. A correlation analysis of the interrelation of oral hygiene, periodontal disease, and selected demographic characteristics is also included. Oral hygiene was

evaluated by the Simplified Oral Hygiene Index, 1

while the prevalence and severity of periodontal disease were measured by the Periodontal

Index. 2

Background (Source of Data)

During 1966-70 the Division of Health Examination Statistics conducted a survey of the health

of the Nation’s youths. The target population was

the 22.7 million noninst itutionalized U.S. youths

aged 12-17 years, living in the United States

(including Alaska and Hawaii), Persons residing

on lands reserved for American Indians were

excluded from the target population. A probability sample of 7,514 youths was selected to

represent the population of U.S. youths. 3 The

sample design and the procedure by which the

sample was selected are described in appendix I.

The 1966-70 survey was the third in the

continuous series of sample surveys conducted

by the Division of Health Examination Statistics

on’ specified segments of the U.S. population

whose health status was determined by direct

examination. The first survey collected information about the health of the Nationts adults aged

18--79 years and focused primarily on selected

chronic healtn conditions and various related

physical and physiological measures.4 The second

survey was designed to assess health factors

related to the growth and development of the

Nation’s children aged 6-11 years. 5 The survey

of youths was similar in design and content to

the children’s survey. The examinations were

conducted in mobile examination centers which

visited 40 randomly selected locations in 25

States.

The Examination

A standardized examination was given to each

consenting sample youth whose parents or guardians consented to his or her participation in

the survey. Physicians, dentists, psychologists,

nurses, and technicians performed tests which

focused on factors related to biological and

psychological aspects of growth and development.

A pediatrician examined the nose, throat, ears,

heart, and neurological and musculoskeletal systems of each youth. The teeth and their supporting structure were examined by a dentist. Intellectual development, school achievement, and

personality development were measured by a

psychologist. Other procedures included tests

of vision, hearing, exercise tolerance, grip

strength, and breathing capacity. Blood pressure

levels and electrocardiograms were recorded as

well as height, weight, and other body measurements.

The dental examination was conducted by

seven specially trained dentists employed at

various times during the survey. The examiners

derived their findings on a uniform basis by

1
following as closely as possible written, objective standards. The standards were guidelines

which narrowed the range of examiner variability by eliminating many borderline or questionable conditions that are persistent sources

of examiner disagreement. To avoid procedures

that might have introduced systematic bias, the

examining dentists were instructed not to dry or

isolate teeth nor to remove oral debris and

calculus. Radiographs of the teeth were not

taken. An adjustable examining chair, a standard

light source, and a mouth mirror and explorer

were used during the examination, which usually

lasted about 10 minutes.

Definitions of dental conditions and procedures for conducting the examinations were

largely the same as those followed during the

Health Examination Surveys of adults during

1960-62 and of children during 1963-65.6’7 The

same two dentists who trained new examiners

during both previous surveys also trained the

other examiners and periodically reviewed the

findings during the survey of youths. A comparison of the findings from replicate dental

examinations (appendix III) suggests that interexaminer variability was reasonably well controlled and did not seriously bias the Periodontal

Index (PI) findings. Appendix III contains a description of the training of examiners.

Nonresponse

At the close of the survey, 90 percent or

6,768 of the 7,514 sample youths had been examined. Although data pertaining to the dental

conditions of the 746 nonrespondents are not

available to the survey staff, it is assumed that

nonresponse did not seriously bias the estimates

contained in this report. This national sample

and the examined group are closely representative of the 22.7 million noninstitutionalized youths

12-17 years old in the United States with respect

to age, sex, race, geographic region, population

size of place of residence, and rate of population

change in size of place of residence from 1950

to 1960.

Limitations of Data

Several limiting factors need to be considered

when using the data contained in this report. The

target population does not include institutionamed

persons nor does it include persons residing on

lands reserved for American Indians. Hence, a

portion of the U.S. population which may contain

a high degree of dental morbidity is not represented in these data. Another consideration

is that these data are based on a sample of the

target population; therefore, national estimates

are subject to sampling error. Sampling errors

are prominently displayed in tables 6-10. In this

report sampling error has been taken into account

by the use of tests of statistical significance as

specified in appendix 1.

SIMPLIFIED ORAL

HYGIENE INDEX (OHI-S)

Oral hygiene status was assessed by the

Simplified Oral Hygiene Index (OHI-S), a method

developed by Green and Vermilion. I In the simplified method the extent of oral debris and

the extent of oral calculus are measured on

selected surfaces of at least two of six predesignated teeth. The buccal surfaces of the

upper molars, the lingual surfaces of the lower

molars, and the labial surfaces of the upper and

lower central incisors are included. The proportion (in thirds) of the total surface area overlaid by debris and the proportion overlaid by

calculus are averaged to give the Simplified

Debris Index (DI-S) and the Simplified Calculus

Index (CI-S). The sum of the CI-S and DI-S is the

Simplified Oral Hygiene Index (OHI-S). Thus,

the OHI-S ranges from a low of 0.0 (no debris,

calculus, or stain) to a high of 6.0 (more than

two-thirds of the examined surfaces covered

with debris and calculus).

Oral Hygiene Findings

The distribution of specified levels of the

Simplified Oral Hygiene Index (OHI-S) scores

among U.S. youths aged 12-17 years is shown

in tables A and 1. The abundance of low OHI-S

scores indicates a favorable level of oral hygiene

am,ong youths. Of the estimated 22.7 million

adolescents, approximately two-thirds, 68.3 percent, had little or no calculus and debris (OHI-S

score of 1.0 or less); about one quarter, 27

2
Table A. Number and percent distribution

of youths by level of Simplified Oral

Il$g~ey~ Index (OHI-S): United States,

.

Number of Percent

OHI-S youths in distrithousands bution

!Y.otal ---------- 22,679\ 100.00

0.0-1.0--------------

m

15,491 68.31

1.1-200-------------- 6,125 27.01

2.1-3.0-------------- 921 4.06

3.1-6.0-------------- 142 .62

percent, had scores ranging from 1.0 through

2.0; but less than 1 percent had scores greater

than3.O (indicating poor oral hygiene).

The estimated average OHI-Sfor all youths

was 0.89 (table 2). The means of the component

indexes of the OHI-S which measure calculus

(CI-S) and debris (DI-S) were 0.11 and 0.77,

respectively. As illustrated in figure 1, the

presence of oral debris is the main reason for

poor oral hygiene among youths.

Although relatively small differences inthe

OHI-S and its components are usually not signif0<90

r

O.OQ I_

DI-S cl-s

icant clinically, they may nevertheless indicate

variations in the prevalence and distribution of

oral hygiene levels that may be significant epidemiologically. In the following sections, differences that are statistically significant ,are cited

even though such differences are not necessarily

clinically significant.

Age

The oral hygiene of adolescents ofall races

tends to improve with advancing age.Althoughthe

decreases in mean OHI-S between successive

years of age are not statistically significant, the

mean OHI-S, nevertheless, appears to decrease

slightly with advancing age and is significantly

higher for younger than for older youths (table

2). For example, the mean OHI-S for 12-yearold youths was substantially greater than that

for 17-year-old youths, 0.94 compared with

0.82. The inverse association between age and

OHI-S is graphically illustrated in figure 2.

The improvement in oral hygiene with advancing age occurs because adolescents, as they :

grow older, have less debris on their teeth. As

shown in figure 3,themean DI-S scores for youths

of all races decrease slightly with advancing age.

The mean DI-S for 12-year-old youths was substantially higher than that for 15-, 16-, and 17-

year-old youths. In contrast, calculus accumulates slightly with advancing age; themean CI-S

for 12-year-old youths was significantly lower

than that for each of the higher age groups

(figure 4).

0.94

AGE IN YEARS

Figurel. Average Simplified Oral Hygiene Index (OH1-S),Debris

Index (DI-S), and Calculus Index (Cl-s) for youths aged 12-17 ‘igure2. Average Simplified Oral Hygiene lndexfor youths by .

years: United States, 1966-70. age: United States, 1966-70.

3
0.38

0.83

0.79

0.74

0.67

12 13 14 16 16 17

AGE IN YEARS

1

Figure3. Average Simplified Debris Index foryouths by age

United States, 1966-70.

The estimates in table 2 also indicate that

there is an inverse association between the mean

OHI-S and age for white youths, that is, as age

increases oral hygiene among white youths tends

to improve, For example, the mean OHI-S for

12- year-old white youths is significantly greater

than that for 17- year-old white youths, 0.91

compared with 0.75. Similarly, the mean OHI-S

for white girls and that for white boys are also

inversely associated with age (figure 5). However,

among Negro youths, the mean OHI-S does not

appear to vary significantly with increasing age

(table 2). It would appear that the weak association

of OHI-S with age found among youths of all races

is merely a reflection of that same association

found among white youths.

Figure 4. Average Simplified Calculus Index for youths by age:

United States, 1966-70.

4

1.WJ

:

0.90

0.60

0.70

0.00

o.oo’t095

0.93

0,92

.MwL J&u_ w&i0.84

-bku.

0.06

12 13 14 15 18 17

AGE IN YEARS

Figure 5. Average Oral Hygiene Index for white youths by sex

and age: United States, 1966-70.

Sex

As measured by the OHI-S female youths

had cleaner teeth than male youths. The mean

OHI-S for girls of all races—O.80—was significantly less than that for boys -O.97 (table 2).

The same difference by sex prevailed at each

given year of age except for 16- year-olds. White

boys also had a substantially higher mean OHI-S

than white girls, 0.92 as compared with 0.74

(table 2).

The oral hygiene of Negro youths does not

appear to be related to sex. The mean ,OHI-S

for Negro boys is not significantly different from

that for Negro girls. In addition, the mean indexes

for Negro boys and girls within any of the age

groups do not differ significantly. Regardless of

age, the mean OHI-S for Negro youths is essentially independent of sex. Thus, the difference

in oral hygiene status associated with sex among

adolescents of all races may be attributed to

that same difference among white youths.

Race

The oral hygiene of white youths was somewhat better than that of Negro youths. The mean

OHI-S for all Negro youths (1.26) was substantially
higher than that for all white youths (0.83). Differences in the oral hygiene Ievelofwhiteand Negro

youths were also found among youths of the same

age. Within each of the six age groups, Negro

youths consistently had higher mean indexes than

white youths (table 2). In addition, both Negro

boys and girls had an appreciably higher mean

OHI-S than white youths of the same sex. For

example, the mean OHI-S for white boys was

0.92 as compared with 1.30 for Negro boys.TIIUS,

the mean OHI-S for Negro youths was significantly

higher than that for white youths regardless of

age or sex.

Expected Value (Age-Control)

In order to control for age, the expected

value is used, Since the previous estimates indicate that age is related to mean OHI-S, an adjustment is made for differences in the age

distribution of the children within each income

and education group by calculating an expected

value. In the income and education sections of

this report, a comparison of mean actual and

expected values for the 12-17 year age range is

used instead of a comparison of mean age-specific

values. Sampling variability for specific age

groups is usually larger than that for the. total

age span because of the smaller number of

sample youths at each age. Because the larger

sampling variability for age- specific groups frequently masks the relationship that exists with

respect to socioeconomic variables, summary

comparison (actual minus expected) is used here

instead of mean age-specific comparisons.

Expected values were calculated by weighting

the age-specific mean OHI-S for the total U.S.

population of youths by the number of youths in

that age group within specified ranges of a given

demographic variable such as family income.

Actual and expected values may differ by chance,

but when the difference between them is statistically significant, one may conclude that the actual

mean 0131-S of a given demographic group is

1.26 —

1.10 —

1.W —

0.90 —

080 —

0,70 —

0.60 —

O.IL

1.20

FAMILY INCOME

Figure 6. Average Simplified OralHygiene Index for youths

aged 12-17 years by family income: United States, 1966-70.

excessively larger or smaller than the mean of

the same group for the United States and that

the excess may not be attributed to age.

Family Income

The degree of oral cleanliness among youths

of all races varied according to annual family income; the average OHI-S tended to decrease as

family income increased. As illustrated in figure

6, adolescents in the lower income groups had

appreciably poorer oral hygiene (higher mean

OHI-S) than those in the higher income groups.

For example, youths whose families earned less

than $3,000 per year had a mean OHI-S of 1.20,

5
GIRLS

0.38

FAMILY INCOME

0.40

0.30

r

i- 0.27

0.20 —

0.10 -

aca —

.0.10 —

-0.20 —

I

.0.23

-0.30L_

L= than $3,~ $5,1Jw $7,w $10,w $15,co0

$3,000 $4,9ee $0,999 $9,999 $14,9S9 or mom

FAMILY INCOME

Figure 7. Difference between actual and expected average Simplified Oral Hygiene Index (OH I-S) for girls and boys aged 12-17 years

by family income: United States, 1966-70.

while youths whose families earned $15,000 or After stratifying

more per year had a mean OHI-S of only 0.64 ciation of the mean

(figure 6 and table 3).

When age was taken into consideration by

contrasting mean actual and expected values,

the inverse relationship between mean OHI-S

and family income continued to be evident (table

3). For instance, youths whose families earned

less than $3,000 per year had a substantially

higher mean OHI-S than expected, whereas,

youths whose families earned $15,000 or more

had a substantially lower OHI-S than expected.

by sex, the inverse assoOHI-S with family income

prevailed among both female and male adolescents. The mean OHI-S scores for female youths

in the lower income groups (less than $3,000 and

$3,000-$4,999) were significantly greater than

expected and those for girls in the higher income

groups ($10,000-$14,999, $15,000 or more) were

significantly lower than expected (figure 7).

Similarly, the mean OHI-S scores for boys in

the lower income groups were appreciably greater

than expected while those for male youths in the

6
higher income groups were appreciably lower

than expected.

The relationship between mean OHI-S and

family income for white youths was similar to

that for youths of all races. As among all races,

the mean OHI-S for white youths varied inversely

with annual family income. The mean OHI- S for

white youths whose families earned less than

$3,000 was substantially greater than that for

white youths in each of the higher income groups.

For instance, the mean OHI-S for white youths

in families with less than $3,000 annual income

was 1.14 as compared with 0.64 for youths whose

families earned $15,000 or more (figure 8).

After age and sex were taken into considerateion, the inverse association between mean OHI-S

and family income continued to prevail among both

white boys and girls (figure 9). Regardless of age

and sex, the mean OHI-S for white youths is inversely associated with annual family income.

The relationship between mean OHI-S and

family income among Negro youths (table 3) is

not clear. With the exception of the $10,000-

$14,999 income group, differences between the

mean OHI-S for the lowest income group and

that for each higher income group are negligible.

For example, the mean OHI-S for Negro adolescents whose families earned $15,000 or more

per year is not significantly different from that

for Negro adolescents whose families earned

less than $3,000. An age control was not applied

to estimates for Negro youths in this and the

following sections, since it was previously shown

that the mean OHI-S for Negro youths was essentially independent of age. Similarly, sexspecific estimates were not discussed because no

relationship between mean OHI-S and sex of

Negro youths was noted.

Education of Parent

The estimated actual and expected mean

OHI-S scores for youths according to sex, race,

&~ sJ,oc& mm. S7,00G $10,OOB $15,003

$6,959 $9,999 $14,999 or more

FAMILY INCOME

Figure 8. Average Simplified Oral Hygiene Index for white youths

aged 12-17 years by family income: United States, 1966-70.

and educational attainment of the youth’s parent

or guardian are shown in table 4. The education

of parents was inversely associated with the

oral hygiene of adolescents. Thus, mean OHI-S

decreased from a high of 1.34 for youths whose

parents had less than 5 years of education to a

low of 0.59 for those whose parents had 17 or

more years of education (figtrre 10). After allowances were made for differences in age, the

inverse association continued to be evident. The

mean OHI-S index for youths whose parents had

7
BOYS

0.41

GIRLS

-0.22

L%: &n &@& woo’ $7,000 $Io,ooo. $15,CK0

S0,999 $9,999 $14,999 or more

FAMILY INCOME

0.30

r

0.25

-0.20

1-

1

-0.30I_

Les than $3,(IO3 $5,002. $7,000. $10,COO. $15,C+YI

$3,CO0 $4,999 $0,999 $9,9S9 $14,999 or more

FAMILY INCOME

Figure 9. Difference between actual and expected average Simplified Oral Hygiene Index (OHI$) for white boys and girls aged 12-17

years by family income: United States, 1966-70.

little or no formal education was greater than

expected while the mean index for those whose

parents had 17 or more years of education was

substantially less than expected. The inverse

association also prevailed between education

and mean OHI-S after stratifying by sex (figures

12 and 13).

As noted for youths of all races, the mean

OHI-S for white adolescents is inversely associated with the educational achievement of their

parents figure 11). The mean OHI-S for white

youths decreased from a high of 1.30 for those

whose parents had less than 5 years of education

to a low of 0.57 for those whose parents had 17

or more years. After age and sex were taken

into consideration, the mean OHI-S for white boys

and girls continued to be inversely associated

with the educational attainment of their parents

(table 4).
1.40 rthan 5

EDUCATIONOF HEADOF HOUSEHOLDIN YEARS

1.s0

1.2U

1.10

1.00

0.90

0.80

0.70

0.6C

0.5C

O.o1

0.76

None 5-7 8 9-11 12 1s-15 16 17 or

or less more

than 5

EDUCATIONDF HEAD OF HOUSEHOLO IN YEARS

Fiaure 11. Averaae Simplified Oral Hygiene Index for white

~“ouths aged 12~17 years by education-of head of household:

United States, 1966-70.

Figure 10. Average Simplified Oral Hygiene Index for youths

aged 12-17 years by education of head of household: United

States, 1966-70.

9
0.60

r

0.50 —

0.40 —

0.30 -

0.20 –

0.10 -

0.00 —

-0.10 –

.0.20 –

.0.30 —

.0.40 L ‘0.37

None 5-7 8 9.11 12 13-15 16 17 or

or Ies more

than 5

EDUCATION OF HEAO OF HOUSEHOLO IN YEARS

Figure 12. Difference between the actual and expected average

Simplified Oral Hygiene Index (OHI-S) for boys aged 12-17

years by education of head of household: United States,

1966-70.

The relationship between the mean OHI-S

for Negro youths and the education of the parent

is not clear. The mean OH[-S for Negro youths

whose parents had less than 5 years of education

was not significantly different from those for the

two highest educational groups (16 years and 17

years or more). On the other hand the mean

OHI-S for Negro adolescents whose parents had

L

.0.=

-0.30

None S.7 a 9.11 12 13-16 16 17

or le98 or mom

than 5

EOUCATION OF HEAO OF HOUSEHOLO IN YEARS

Figure 13. Difference between the actual and expected average

Simplified Oral Hygiene Index (OHI-S) for girls aged 12-17

years by education of head of household: United States,

1966-70.

13-15 years of education was substantially less

than that for Negro youths whose parents had

less than 5 years of education (table 4).

Since there are appreciably more white than

Negro youths in the United States, findings for all

races reflect to a great extent the findings for

white youths. Thus, as noted for youths of all

races, the mean OHI-S for white youths was

inversely associated with both family income and

with the education of parents. However, the

relationship between the mean OHI-S for Negro

youths and either family income or parent’s

education was not clear.

Geographic Region

The mean OHI-S for girls of all races was

substantially higher in the South—0.93—than in

10
the West—O.69 (table 5). After age was accounted

for, the mean OHI-S for girls remained higher

for those in the South than for those in the West.

Table 5 also contains estimates of the average

OHI-S by race. The mean oral hygiene estimates

for white adolescents, regardless of their sex or

age, did not differ significantly among the regions.

Similarly, the estimates for Negro youths did not

vary by region.

DISCUSSION

Interrelation of OHI-S and Selected

Demographic Variables

The interrelation of OHI-S and selected

demographic characteristics may be further assessed by the statistical method of correlation

analysis. By this method, the relative strength

of the association of selected variables (age,

sex, race, family income, and education of parent)

with OH1-S is quantified separately” by calculating simple correlation coefficients. The simple

correlation coefficients shown in table B indicate

that age, sex, race, family income, and parent’s

education are related in varying degrees to oral

hygiene. These correlations would be expected

since the mean OHI-S was previously shown to

be related to age, sex, race, income, and education. Further insight into the relationship of the

variables with oral hygiene may be obtained from

the partial correlation coefficients in table B

which quantify the correlation between each vari- “

able and oral hygiene when the associations

between the ‘other variables and OHI-S are held

constant.

Family income and parent’s education have

been shown to be associated with oral hygiene.

However, family income is also highly correlated

with education in the United States (r= 0.56). Two

questions now arise: First, is education independently associated with oral hygiene, or is the

association due to the correlation between income

and education? Second, is family income independently associated with oral hygiene, or is the association a reflection of the correlation between

education and income?

With income, age, sex, and race held constant, the partial correlation between education

and the oral hygiene index is substantially differTable B. Correlation coefficients between the Simplified Oral Hygiene Index and selected variables with standard errors: United States, 1966-70

Partial

Simple correlation

Variable correlation Standard coefficient Standard

coefficient error for 6- error

variable

equation

Age -------- -------- -------- -------- ---- -.06 .015 -.07 .017

Sex------------------------------------ -.13 .017 .-.14 .017

Race ----------------------------------- .22 .057 .12 .050

Family income-------------------------- -.30 .027 -.13 .019

Education of “parent -------------------- -.29 .025 -.16 .017

11
Table C. Correlation coefficients between the Periodontal Index (PI) and selected

variables with standard errors: United States, 1966-70

Variable

OHI-S ----------------------------------

Age------------------------------------

Race -------- ----------------- -----------

Family income -------- ------------------

Education of parent --------------------

I I Partial I

Simple correlation

correlation Standard coefficient Standard

error for 7- coefficient error

variable

equation

.62 .019 .59 .017

.06 ;O& ● 12 ● 013

.12 -.04 .048

-.21 .019 -.02 .021

-.22 .024 -.04 .027

ent from zero. The partial correlation between

income and the oral hygiene index is also significantly different from zero when the effects of

education, age, sex,” and race are held constant

(table B). Thus it would appear that both education and income are independently associated

with oral hygiene.

Interrelation of Plr OHI-S, and

Selected Demographic Variables

Previous U. S. surveys conducted by the

Division of Health Examination Statistics on

adults 18-79 years and on children 6-11 years

have presented data concerning the relationship

between oral hygiene and periodontal disease

(an inflammatory disease of thesupporting structures of teeth). In order to make a similar

analysis of the association of periodontal disease

with oral hygiene among adolescents, Russell’s

Periodontal Index is now presented. Periodontal

disease is of special interest to dental epidemiologists and others since it is a leading cause

of tooth 10SS.

Periodontal lndex(Pl)

The prevalence and severity of periodontal

disease among U,S. youths were assessedby the

Periodontal Index (PI). 9 The PI is a score for

each tooth in the mouth, provided it isnota root,

according to the presence and severity ofperiodontal disease. Ascoreof zero is assigned when

no indication of disease is found. When a portion

of the free gingiva is inflamed, a score of 1 is

assigned. If completely circumscribedby inflammation, the tooth is scored 2, Teeth with

overt periodontal pockets are scored 6 if their

masticator function is unimpaired and 8 ifit is

impaired. An individual’s PI is the arithmetic

average of all scores. The PI ranges from 0.0

(no inflammwion or pockets) to 8.0 (all teeth with

pockets and impaired function).

Table C presents the simple and partial

correlation coefficients relating the Periodontal

Index (PI) with the Simplified Oral Hygiene Index

(OHI-S) and selected demographic variables.

By comparing the partial coefficients with the

corresponding simple correlation coefficients,

one may determine the degree of independent

correlation each variable has with the PI. As

indicated by simple correlation coefficients in

table C, periodontal disease is significantly

related in varying degrees to age, race, family

income, education of parent, and OHI-S.

After calculating the partial correlation coefficients only twovariables appear to beindependently associated with periodontal disease. With

12
age, race, family income, and education held

constant, the partial correlation between the

OHI-S and the PI is substantially greater than

zero. Similarly, the partial correlation between

age and the PI is significantly greater than zero

when the effects of race, family income, education, and OH[-S are held constant. Thus oral

hygiene and, to a lesser degree, age emerge as

the factors significantly associated with the prev.

alence and severity of perindnntal disease.

As noted before, the association of periodontal disease with oral hygiene among U.S.

adults aged 18-79 and U.S. children 6-11 years

has been investigated previously. Periodontal

disease among adults was found to be related

to oral hygiene and to various demographic

variables (age, sex, race, income, education).

Analysis showed that differences in the occurrence of periodontal disease associated with all

the given demographic variables except age,

were largely accounted for by significant variations in oral hygiene status. Thus age and oral

Table D. Mean Sintplified Oral Hygiene

Index (OHI-S) for children, 1963165,

youths, 1966-70, and adults, 1960-63, by

age: United States

Age I

Mean

OHI- S

Children 6-11. years -------------

Youths 12-17 years --------------

Adults :

18-24 years -------------------

25-34 years -------------------

35-44 years -------------------

45-54 years -------------------

55-64 years -------------------

65-74 years -------------------

75-79 years -------------------

1.44

0.89

1.35

1.41

1.49

1.74

1.78

2.06

2.11

hygiene were significant variablesassociated with

periodontal disease among adults.

Among children, a correlation analysis was

also used to determine the interrelation ofperiodontal disease, oral hygiene, and selected demographic variables. The analysis also showed

that age and oral hygiene were prominent factors

associated with the occurrence of periodontal

disease.

(

In summary, oral hygiene and age consistently emerged as statistically significant factors

associated with the prevalence and severity of

periodontal disease among the U.S. population

aged 6-79 years.

OHI-S FINDINGS FROM

PREVIOUS HES REPORTS

The estimates presented in this report are

part of an epidemiologic study of the dental health

of the civilian, noninstitutionalized population

aged 6-79 years in the United States. The first

report in the dental series contained national

estimates of the oral hygiene status of adults

aged 18-79 years (1960-62). The second of these

reports presented estimates for children 6-11

years (1963-65). The mean OHI-S scores for

successive age groups in all three surveys are

shown in table D.

The average OHI-S for children, youths, and

young adults is shown in table E. The estimates

for youths are obviously lower than it would

appear they should be. The estimate forl2-yearolds interrupts a gradually declining trend with

age by dropping sharply below the estimate for

11-year-olds. Furthermore, the estimate for

17-year-olds is well below that for 18-year-olds.

It is possible that the oral hygiene status of

the population improved measurably during the

10-year period over which the successive surveys

were conducted. It is also possible that the low

13
Table E. Mean Simplified Oral Hygiene

Index (OHI-S> for children. 1963-65.

youths, ”1966-70, andyoung adfilts, 1960~

63, by single year of age: United States

Age

Children 6-11 years:

6 years -----------------------

7 years -----------------------

8 years -----------------------

9 years -----------------------

10 years ----------------------

11 years ----------------------

Youths 12-17 years:

12 years ----------------------

13 years ----------------------

14 years ----------------------

15 years ----------------------

16 years ----------------------

17 years ----------------------

Young adults 18-24 years:

18 years ----------------------

19 years ---------------------- 9

20 years ----------------------

21 years ----------------------

22 years ----------------------

23 years ----------------------

24 years ----------------------

Mean

OH1-S

1.38

1.50

.1.49

1.47

1.41

1.40

.94

.92

.90

.87

.86

.82

1.18

1.33

1.52

1.31

1.31

1.41

1.33

estimates foryouths reflect,atleast inpart,intersurvey differences in applying the Simplified

Oral Hygiene Index. There is no entirely convincing evidence that will support the occurrence

of either possibility. However, the cumulative

percent distribution of OHI-S scores collected

during the three surveys by individual examiners

suggests that an improvement in oral hygiene

status didoccur (appendixI,table 11).Forexample,

1 percent of all OHI-Sscores for children were

O.O, and less than 23 percent were under0.9. For

youths, on the other hand, more than 6 percentof

all scores were O.Oandmorethan 57percent were

under 0.9. In addition, amuch higher proportion

of low scores were given among youths than

among children by both examiners 1 and2—the

senior dentists who trained all other dentists

during the surveys. Thus the oral hygiene findings of the individual examiners show that most

of them found relatively more youths than children with low OHI-Sscores. The correspondence

during the surveys of the findings of the senior

dentists with those of the o:her dentists suggests

that intersurvey differences in oral hygiene estimates are not due to a difference in the applicationof the 0131-S.

It should be pointed out here that there is

evidence of a significant imp~ovement in the

dental heakhof the U.S. population during recent

years. From 1959 to1969, the percent ofpatients

receiving preventive treatment—prophylaxis, radiographic examination, and orthodontic and root

canal treatments—increased, and the percent

receiving reparative treatment—fillings, extractions, and dentures—decreased. l” In addition,

national estimates from the Health Interview

survey, another program of the National Center

for Health Statistics, show that the percent of

adults 45 years or over who have lost allof

their natural teeth declined during the 13-year

period that ended in 1971.11

In some instances but not in others, the

association of OHI-S with selected demographic

variables prevailed during childhood, adolescence, and adulthood. For example, mean oral

hygiene indexes decreased slightly with advancing age during childhood and adolescence. In

contrast, mean OH1-S scores among adults increased sharply with advancing age, Analysis of

the scores by sex and race shows that the association of OHI-Sdiffered among adults, youths,

and children. Mean oral hygiene did not vary by

sex for children, but mean scores among male

adolescents and adults were higher than those

for females of the same ages. Mean scores were

also not associated with race during childhood,

whereas, mean scores for Negro adolescents and

adults were higher than those for white persons

of comparable age and sex.

The association of 0[+1-S with both family

income and education prevailed among children,

youths, and adults. In contrast, meanoralhygiene

indexes did not vary consistently byregionarnong

the three age groups.

SUMMARY

The national estimates in this report of the

oral hygiene status of youths are based on data

collected by the Division of Health Examination

Statistics during 1966-70. A probability sample

of 7,514 youths in the civilian, noninstitutionalized population was scientifically selected to

14
represent the Nation’s youths 12-17 years of age.

Of these, the 6,768 examined youths, 90 percent

of the sample, were closely representative of the

Nationts adolescent population with respect to

age, race, region of residence, family income:

and education of parent.

The dental examinations were given by dentists trained to obtain their findings on a uniform

basis. Oral hygiene was assessed by the Simplified Oral Hygiene Index (OHI-S), which reflects

the presence or absence of oral debris (soft

foreigm material attached to the tooth) and/or

calculus (hardened foreign material firmly attached to the tooth).

The abundance of low OHI-S scores indicates

a favorable level of oral hygiene among adolescents. Of the estimated 22.7 million U. S. youths,

approximately two-thirds had little or no calculus

and debris (OHI-S of 1.0 or less), and less than

1 percent had faulty oral hygiene (OH1-S score in

excess of 3.0).

The average OHI-S for approximately 22.7

million adolescents was 0.89. The component

indexes of OHI-S that measure oral debris (DI-S)

and oral calculus (CI-S) were 0.77 and 0.11, respectively. The component indexes show that poor

oral hygiene among youths is mainly due to the

presence of oral debris.

As measured by OHI-S, oral hygiene among

all youths tends to improve slightly with advancing age. The mean OHI- Swas significantly higher

among younger youths than among older ones.

The mean OHI-S decreased from a high of 0.94

for 12-year-old youths to a low of 0.82 for 17-

year-old youths.

The improvement in oral hygiene with advancing age parallels the association between oral

debris and age. Among youths of all races, the

mean debris indexes decreased with advancing

age, Calculus, on the other hand, tends to accumulate slowly with advancing age. Thus the

improvement in overall oral hygiene with advancing age is due to the lower level of oral

. debris among older adolescents.

Oral hygiene among both male and female

white youths improved with advancing age as

it did for youths of all races. Among Negro youths,

however, oral hygiene did not appear to be related to age.

The oral hygiene of youths of all races varied

by sex—girls had cleaner teeth than boys. The

mean OHI- S for girls of all races (0.80) was

significantly less than that for boys (0.97). Within

five of the six age groups, the mean OHI-S of

girls was appreciably less than that of boys.

White boys had a substantially higher mean

OHI-S than white girls. But among Negro youths,

the average OHI-S was essentially independent

of sex regardless of age.

Significant differences in oral hygiene were

associated with race. The mean OHI-S for all

Negro youths (1.26) was significantly greater

than that for all white youths (0.83). Both Negro

boys and girls had materially higher mean indexes

than white youths of the same sex. Within the same

age groups, Negro adolescents also had appreciably higher mean scores than white adolescents.

The degree of oral cleanliness of youths

varied according to family income; the average

OHI-S tended to decrease as family income increased. Among youths of all races, for example,

the mean OHI- S for those with a family income

of less than $3,000 per year was 1.20, but it was

only 0.64 for those whose families earned $15,000

per year or more.

As with family income, education of the

parent was inversely related to the mean OHI-S

for adolescents. This was not unexpected since

income and education are highly correlated in

the United States. However, it was also found that

income and education were independently associated with oral hygiene.

The mean OHI-S for girls of all races, regardless of age, was substantially higher in the South

than in the West. The mean oral hygiene estimates

of white and Negro adolescents did not differ

significantly by region, regardless of sex or age.

The interrelation of oral hygiene, periodontal disease, and selected demographic variables was also analyzed. A correlation analysis

showed that age and oral hygiene were the most

significant variables associated with the prevalence and severity of periodontal disease among

youths.

000

15
REFERENCES

1

Greene, J. C., and Vermilion, J. R.: The Simplified Orid

Hygiene Index. j. Am. Dent. Assoc. 68(1):7-13, Jan. 1964.

2

Russell, A. L.: A system of classification and scoring for

prevalence surveys of periodontal disease. J, Dent. Res.

35(3):350-359, June 1956.

3

National Center for Health Statistics: Phm and operation of

a Health Examination Survey of U.S. youths 12-17 years of

age. Vital and Health Statistics. PHS Pub. No. 1000-Series

1-No, 8. Public Health Service. Washington, U.S. Government

Printing Office, Sept. 1969.

4

National Center for Heakh Statistics: Cycle Iofthe Heakh

Examination Survey: sample and response. Vital and Health

Statistics. PHS pub. No. 1000-Series 11-No. 1. Public Health

Service. Washington. U.S. Government Printing Office, Apr.

1964.

5

Natiomd Cerrter for Heakh Statistics: Plan, operation, and

response results of a program of children’s examinations. Vital

and HeaWStatistics. PHSPub. No. 1000-Series l-No. 5. public

Health Service. Washington. U.S. Government Printing Of~ce,

Oct. 1967.

6

Natiomd Center for Health Statistics: Selected dental

findings in adults by age, race, and sex, United States,

1960-1962. Vital and Health Statistics. PHS Pub. No.

1000-Series 1l-No. 7. Public Health Service. Washington, U.S.

Government Printing Office, Feb. 1965.

7

Natiomd Center for Health Statistics: Periodontal disease

and oral hygiene among children: United States, 1963-65. Vital

and Health Statistics. Series 1l-No. 117. DHEW Pub. No.

(HSM) 72-1060. Washington. U.S. Government Printing Office,

June 1972.

8

National Center for Health Statistics: Pseudoreplication,

further evaluation and application of the balanced half-sample

technique. Vital and Health Statistics. PHS pub. No.

1000-Series 2-No. 31. Public Health Service. Washington. U.S.

Government Printing Office, Jan. 1969.

9

Natiomd Center for Health Statistics: Periodontal disease

among youths 12-17 yezs: United States. Vital and Health

Statistics. Series 11-No. 141. DHEW Pub. No. (HRA) 74-1623.

Washington. U.S. Government Printing Office, June 1974.

10

Moen, D. B., and Poetsch, W. E.: More preventive care,

less tooth repair: survey of dental services rendered, 1969. j.

Am. Dent. Assoc. 81(1):25-36, July 1970.

11

National Center for Health Statistics: Edentulous Persons:

United States, 1971. Vital and Health Statistics. Series 1O-NO.

89. DHEW Pub. No. (HRA) 74-1516. Washington. U.S.

Government Printing Office, June 1974.

16
LIST OF DETAILED TABLES

Table 1.

2.

3.

4.

5.

6.

7.

8,

9.

10.

Number and percent of youths aged 12-17 years, by Simplified Oral Hygiene Index

(OHI-S) and sex: United States, 1966-70 --------- ---------------------------------

Average Simplified Oral Hygiene Index (OHI-S), Debris Index (DI-S), and Calculus

Index (cI-S) for youths, by race, sex, and age: United States, 1966-70----------

Actual and expected average Simplified Oral Hygiene Index (OHI-S) for youths

aged 12-17 years, by sex, race, and family income: United States, 1966-70-------

Actual and expected average Simplified Oral Hygiene Index (OHI-S) for ~g~

aged 12-17 years, by sex, race, and education of head of household:

States, 1966-70 -----------------------------------------------------------------

Average Simplified Oral Hygiene Index (OHI-S) for youths aged 12-17 years, by

sex, race, and geographic region: United Statea, 1966-70------------------------

Standard errors of the number and percent of youths aged 12-17 years, by Simplified Oral Hygiene Index (OHI-S) and sex: United States, 1966-70-----------------

Standard errors of the average Simplified Oral Hygiene Index (OHI-S), Debris

Index (DI-S),and Calculus Index (CI-S) for youths, by race, sex, and age: United

States, 1966-70 -----------------------------------------------------------------

Standard errors of the average Simplified Oral Hygiene Index for youths aged

12-17 years by sex, race, and family income: United States, 1966-70-------------

Standard errors of the average Oral Hygiene Index for youths aged 12-17 years by

sex, race, and education of head of household: United States, 1966-70-----------

Standard errors of the average Oral Hygiene Index for youths aged 12-17 years by

race and geographic region: United States, 1966-70------------------------------

Page

18

19

20

21

22

23

24

25

26

27

17
Table 1. Number and percent of youths aged 12-17 years, by SimplifiedOral Hygiene Index (OHI-S)

and sex: United States, 1966-70

OHI-S

Total--------------------------------------

o.o----------------------------------------------

o.l----------------------------------------------

o.2----------------------------------------------

o*3----------------------------------------------

o.4----------------------------------------------

o.5----------------------------------------------

O.6----------------------------------------------

o.7----------------------------------------------

O.8----------------------------------------------

o.9----------------------------------------------

1.0----------------------------------------------

l.l----------------------------------------------

1.2----------------------------------------------

l.3----------------------------------------------

l.4----------------------------------------------

l.5----------------------------------------------

l.6----------------------------------------------

l.7----------------------------------------------

l.8----------------------------------------------

1.9---------------------------------------------

2.o--------------------------:-------------------

2.1-------------------------------.--------------

2.3---------------------------- -------------------

2.4-------------------------------=------------

2.5----------------------------------------------

2.6----------------------------------------------

2.7--------------------------------,--------------

2.8----------------------------------------------

2.9----------------------------------------------

3.o----------------------------------------------

3.l----------------------------------------------

3.2 or more--------------------------------------

Both

sexes IIBoys I

Girls

Number in thousands

22,679

1,531

1,428

2,842

60

2,308

46

2,681

2,288

2,306

1,622

1,481

31

1,052

51

786

611

491

277

189

11

156

7

123

86

72

142

11,476

622

647

1,094

23

1,079

25

1,226

1,209

1,295

940

900

13

604

36

469

348

289

186

118

8

95

77

59

38

76

11,203

909

781

1,748

37

1,230

21

1,455

1,079

1,011

681

582

18

448

15

317

263

202

91

71

3

61

7

46

27

34

65

Both

sexes

100.0

6.75

6.30

12.53

.27

10.18

.20

11.82

10.09

10.17

7.15

6.53

.14

4.64

.22

3.46

2.69

2.16

1.22

.83

.05

.69

,03

.54

.38

.32

.62

Percent

100.0

5.42

5.64

9.53

.20

9.40

.22

10.69

10.54

11.28

8.20

7.84

.11

5.26

.32

4.08

3.03

2.52

1.62

1.02

.07

.83

.67

.51

.33

.67

100.0

8.12

6.97

15.60

.33

11.00

.19

13.00

9.63

9.02

6.08

5.19

.16

4000

.13

2.83

2.35

1.80

.81

.64

.02

.54

.06

.41

,24

.30

.58

1

Includes all racial groups.

18
Table 2. Average Simplified Oral Hygiene Index (OHI-S), Debris Index (DI-S), and Calculus Index

(CI-S) for youths, by race, sex, and age: United States, 1966-70

Sex and age

12

13

14

15

L6

17

12

13

14

15

16

17

12

13

14

1.5

16

17

Both sexes 12-17

years----------------

years-------------------

years-------------------

years..--------------=--

years-------------------

years-------------------

years-------------------

Boys 12-17 years -----

years--------------------

years.---.=-------------

years--------------------

years-------------------

years=------------------

years-------------------

Girls 12.17 years----

years=----------------==

years-------------------

years-------------------

years -------------------

years -------------------

years -------------------

Totall

.89

.94

.92

,90

.87

.86

.82

.97

1.04

.99

.98

.96

.91

.93

.80

.85

.84

.82

.78

.80

.72

OHI-S

Jhite

.83

.91

.87

.83

.81

.78

.75

.92

1.00

.95

.93

.92

.84

.86

.74

.82

.79

,74

.70

.73

.64

Negro

1.26

1.19

1.18

1.32

1.25

1.33

1.29

1.30

1.29

1.21

1.31

1.22

1.40

1.40

1.22

1.08

1.16

1.33

1.29

1.26

1.19

Totall

.77

.88

.83

.79

.74

.70

.67

.85

.96

.90

.86

.82

.76

.77

.69

.80

.75

.72

.66

.64

.58

DI-S

Jhite

.74

.86

.80

.76

.71

.68

.64

.83

.94

.88

.84

.80

.74

.74

.66

.77

.71

.68

.62

.61

.54

Negro

.96

1.04

.99

.99

.93

.90

.89

1.01

1.13

1.02

1.02

.96

.94

.98

.91

.95

.97

.97

.91

.87

.80

CI-S

Totall

.11

.06

.08

.11

.12

.15

.14

.11

.07

.08

.11

,13

.14

.15

.11

.05

.09

.10

.12

.16

.14

White

.08

.05

.07

.07

.09

.11

.11

.09

.05

.06

.08

.11

.10

.12

.08

.04

.07

.06

.08

.12

.10

Negro

.29

.14

.19

.32

.31

.42

.40

.29

.16

.18

.29

.25

.46

.41

.30

.12

.19

.35

.38

.38

.39

1

Includes all racial groups.

19
Table 3. Actual and expectedaverageSimplifiedOral HygieneIndex (OHI-S)for youthsaged 12-17years,

bv sex. race. and familyincome:UnitedStates.1966-70

Race and family

income

Totall

Less than $3,000-----------

$3,000-$4,999--------------

$5,000-$6,999--------------

$7,000-$9,999--------------

$10,000-$14,999------------

$15,000or more------------

Unknown--------------------

White

Less than $3,000-----------

$3,000-$4,999--------------

$5,000-$6,999--------------

$7,000-$9,999--------------

$10,000-$14,999------------

$15,000or more------------

Unknown--------------------

Negro

Less than $3,000-----------

$3,000-$4,999--------------

$5,000-$6,999--------------

$7,000-$9,999--------------

$10,000-$14,999------------

$15,000or more------------

Unknown--------------------

Both sexes Boys Girls

I I I I

Actual -

Differpe%ed ence ence

Ex- Differ-

‘ctual petted ence

OHI-S

1.20

1.10

.95

.82

.69

.64

.94

1.14

1*O3

.90

.80

.68

.64

.86

1.30

1.30

1.24

1.10

1.02

1.05

1.42

.89

.89

.89

.89

.89

.88

.88

.83

.83

.83

.83

.83

.82

.82

1.26

1.25

1.26

1.26

1.27

1.26

1.27

.31

.21

.06

-.07

-.20

-.24

.06

.31

.20

.07

-.03

-.15

-.18

.04

.04

.05

-.02

-.16

-.25

-.21

.15

1.34

1.21

1.02

.89

.77

.71

1.03

1.32

1.14

.98

.87

.76

.70

● 99

1.36

1.41

1.26

1.07

1.03

1.14

1.37

.96

.97

.97

.97

.97

.97

.96

.91

.92

.92

.92

.92

.92

.91

1.30

1.30

1.30

1.31

1.30

1.34

1.32

.38

.24

.05

-.08

-.20

-.26

.07

.41

.22

.06

-.05

-.16

-.22

.08

.06

.11

-.04

-.24

-.27

-.20

.05

1.08

.99

.88

.74

.61

.57

.83

.99

.92

.82

.72

.60

.56

.71

1.25

1.19

1.22

1.13

1.02

.96

1.47

.81

.81

.80

.81

.80

.80

.80

.74

,74

.74

.74

.74

.73

.73

1.22

1.22

1.21

1.21

1.22

1.21

1.22

.27

.18

.08

-.07

-.19

-.23

.03

.25

.lE

.08

-.02

-.14

-.17

,02

.03

-.03

.01

-.08

-.20

-.25

,25

lIncludesall racialsOUPS.

20
Table 4. Actual and expected average Simplified Oral Hygiene Index (OHI-S) for youths aged 12-17years,

by sex, race, and education of head of household: United States, 1966-70

Race and education

of head of household

Totall

None cm less than 5 years--

5-7 years------------------

8 years--------------------

9-11 years-----------------

12 years-------------------

13-15 years----------------

16 years-------------------

17 years or more-----------

Unknown--------------------

White

None or less than 5 years--

5-7 years------------------

8 years--------------------

9-U years -----------------

12 years -------------------

13-15 years----------------

16 years-------------------

L7 years or more-----------

Unknown--------------------

Negro

None or less than 5 years--

5-7 years------------------

8 years--------------------

9-11 years-----------------

12 years-------------------

13-15 years----------------

16 years-------------------

17 years or more-----------

Unknown--------------------

Both sexes II Boys I

Girls

I

1.34

1.10

.98

.96

.78

.70

.63

.59

1.08

1.30

1.04

.95

.88

.76

.68

.62

.57

.90

1.43

1.26

1.30

1.27

1.05

1.04

1.03

.92

1.52

.89

.89

.88

.89

.89

.89

.89

.89

.88

.83

.83

.83

.83

.83

.83

.83

.83

.82

1.26

1.25

1.26

1.26

1.26

1.26

1.23

1.26

1.28

.45

.21

.10

.07

-.11

-.19

-.26

-.30

.20

.47

.21

.12

.05

-.07

-.15

-.21

-.26

.08

.17

.01

.04

.01

-.21

-.22

-.20

-.34

.23

OHI- S

L.52

1.20

1,.08

1.03

.86

.77

.74

.60

1.16

1.53

1.14

1.06

.95

.85

.75

.73

.60

1.07

1.49

1.35

1.29

1.37

1.03

1.19

.84

.83

1.48

.97

.96

.97

.97

.97

.97

.98

.97

.96

.91

.91

.92

.92

.92

.92

.93

.92

.90

1.30

1.29

1.31

1.31

1.29

1.32

1.31

1.32

1.33

.55

.24

.11

.06

-.11

-.20

-.24

-.37

.20

.62

.23

.14

.03

-.07

-.17

-.20

-.32

.17

.19

.06

-.02

.06

-.26

-.13

-.47

-.49

.15

1.18

1.00

.89

.8Z

.70

.63

.54

.56

1.01

1.08

.95

.84

.81

.67

.61

.52

.54

.72

1.38

1.15

1.31

7..18

1.06

.92

1.39

1.16

1.54

Ex- Differpected ence

.81

.8C

.8C

.8C

.81

.8C

.8C

.80

.80

.75

.74

.73

.74

.74

.73

.73

.74

.73

1.23

1.21

1.23

1.21

1.22

1.20

1.15

1.15

1.23

.37

.20

.09

.08

-.11

-.17

-.26

-.24

.21

.33

.21

.11

.07

-.07

-.12

-.2L

-.20

-.01

.15

-.06

.08

-.03

-.16

-.28

.24

.01

.31

lIncludes all racial groups.

21
Table 5. Average Simplified Oral Hygiene Index (OHI-S) for youths aged 12-17 years, by sex, race,

and geographic region: United States, 1966-70

Race and geographic region

Totall

Northeast ------------------------------------------------------

South------------------------------ --------------------------- -

West ......--------------------- --------------------------- -----

White

Northeast ------------------------------------------------------

Midwest ------------------.........--------------------------- --

South----------------------------------------------------------

West -----------------------------------------------------------

Negro

Midwes e--------------------------- --------------------------- --

souch-.......-------------------- ---------.....................

West -----------------------------------------------------------

Both sexes Boys Girls

.90

.85

1.O1

.80

.86

.83

.86

.78

1.18

1.14

1.41

1.01

.95

.94

1.09

.90

.92

.92

.96

.89

1.22

1.15

1.45

1.10

.85

.77

.93

.69

.74

.76

.68

1.15

1.12

1.36

.91

1

Includes all racial groups.

22
Table 6. Standarderrorsof the number and percent of youths aged 12-17 years, by SimplifiedOral

Hygiene Index (OHI-S)and sex: United States, 1966-70

OHI-S

Total------------------------------------------

0.0------------------------------------------------

0.1--------------------------------------------------

0.2------------------------------------------------

O*3--------------------------------------------------

0.4---------------------------------------------------

0.5------.,-------------------------------------------

0.6--------------------------------------------------

0.7------------------------------------------------

0.8------------------------------------------------

0.9---------------------------- -----------------------

l.o--------------------------------------------------

l.l--------------------------------------------------

l.2--------------------------------------------------

1.3------------------------------------------------

l.4--------------------------------------------------

l.5--------------------------------------------------

l.6--------------------------------------------------

l.7--------------------------------------------------

l.8--------------------------------------------------

l.9--------------------------------------------------

2.o--------------------------------------------------

2*l--------------------------------------------------

2.2------------------------------------------------

2.3--------------------------------------------------

2.4--------------------------------------------------

2.5------------------------------------------------

2.6------------------------------------------------

2.7--------------------------------------------------

2.8--------------------------------------------------

2.9--------------------------------------------------

3.0------------------------------------------------

3.1--------------------------------------------------

3,2 or more----------------------------------------

Standard error

of number

in thousands

10

160

140

146

17

145

11

105

101

82

113

110

8

90

13

70

60

66

25

34

6

31

5

24

14

18

24

10

84

85

66

7

92

12

76

68

48

68

65

5

57

10

38

25

45

24

28

5

25

22

11

12

14

1

92

73

104

15

78

7

82

66

63

73

58

7

58

7

45

46

34

16

16

3

14

5

15

8

11

17

=

Standard error of

percent

.70

.62

.64

.08

.64

.05

.46

.44

.36

.50

.48

.04

.40

.06

.31

.26

.29

.11

.15

.02

.13

.02

.10

.06

.08

.11

.73

.74

.58

.06

.80

.10

.66

.59

.42

.59

.57

.04

.49

.09

.33

.22

.39

.21

.25

.04

.22

.19

.10

.11

.12

.82

.65

.93

.13

.70

.06

.73

.59

.56

.65

.52

.06

.52

.06

.41

.41

.30

.15

.14

.02

.12

.04

● 13

.07

.09

.15

l~ncludesall racial grouw~

23
Table 7. Standard errors of the average Simplified Oral Hygiene Index (OHI-S), Debris Index

(DI-S), and Calculus Index (CI-S) for youths, by race, sex, and age: United States, 1966-70

OHI-S I

DI-S

I

CI-S

Sex and age

Total’ II I

Negro White Negro

, II I

Standard error

Both sexes 12-17

years --------------- .03 .03

.03

.03

.04

.04

.04

.04

.03

.03

.03

.04

.04

.05

.05

.03

.10

.10

.09

.13

.11

.11

.14

.11

.12

.11

.17

.12

.11

.17

.10

.03

.03

.04

.04

.03

.04

.03

.03

.03

.03

.03

.04

.03

.04

.03

.03

.09 .01

.01

.01

.01

.01

.02

.02

.01

.01 .03

.01

.01

.01

.01

.01

.01

.01

12

13

14

15

16

L7

years -------------------

years -------------------

years -------------------

years.--.=--------------

years.--.--..----.-=----

years-=------------.=---

.03

.03

.04

.03

.04

.04

.03

.08

.10

.14

.08

.08

.11

.10

.02

.03

.04

.06

.06

.06

Boys 12-17 years----- .03

years -------------------

years -------------------

years -------------------

years -------------------

years -------------------

years=------------------

12

13

14

15

16

17

.03

.04

.05

.03

.04

.05

.03

.03

.04

.04

.03

.04

.04

.03

.03

.03

.04

.04

.04

.04

.03

.08

.13

.16

.10

.09

.14

.08

.01

.01

.01

.01

.01

.02

.01

.01

.01

.01

.01

.01

.02

.01

.01

.01

.01

.01

.02

.02

.04

.04

.03

.07

.06

.06

Girls 12-17 years---- .04

.02

.03

.06

,06

.07

.09

12

13

14

15

16

17

years -------------------

years -------------------

years -------------------

years -------------------

years -------------------

years -------------------

.04

.04

.04

.04

.04

.05

.04

.04

.04

.04

.04

.04

.09

.09

.10

.12

.14

.16

.04

.04

.04

.04

.04

.03

.04

.04

.04

.04

.04

.03

.09

.09

.12

.07

.10

.10

.01

.01

.01

.01

.02

.02

1

Includes all racial groups.

24
Table 8. Standard errors of the average Simplified Oral Hygiene Index for youths aged 12-17 years

by sex, race, and family income: United States, 1966-70

Race and family income

Totall---------------------------------------------------

Less than $3,000-----------------------------------------------

$3,ooo-$4,999--------------------------------------------------

$5,OOO-$6,999--------------------------------------------------

$7,ooo-$9,999--------------------------------------------------

$lo,ooo-$l4,999------------------------------------------------

$15,000 or more------------------------------------------------

Unknom --------------------------------------------------------

White --------------------------- -------------------------

Less than $3,000-------------------------------- ---------------

$3,ooo-$4,999--------------------------------------------------

$5,000-$6,999------------------------------------------------

$7,ooo-$9,999--------------------------------------------------

$lo,ooo-$l4,999------------------------------------------------

$15,000 or more--------------------------- ---------------------

Unknom --------------------------------------------------------

Negro------------------------------------ ----------------

Less than $3,000-----------------------------------------------

$3,000-$4,999------------------------------------------.-------

$5,OOO-$6,999--------------------------------------------------

$7,ooo-$9,999--------------------------------------------------

$lo,ooo-$l4,999------------------------------------------------

$15,000 or more------------------------------------------------

Unknown------------------ ---------------------------- --------- -

llnclude~ all racial grouw.

Both sexes Boys Girls

Standard error

.03

.05

.05

.04

.03

.03

.04

.06

.03

.03

.03

.04

.03

.03

.04

.05

.10

.11

.14

.12

.09

.09

.39

.15

.03

.06

.05

.05

.03

.03

.04

.06

.03

.05

.03

.05

.03

.03

.04

.06

.11

.12

.14

.17

.12

.07

.37

.20

.03

.06

.06

.04

.04

.03

.04

.07

.03

.04

.05

● 04

.04

.04

.04

.05

.10

.10

.14

.14

.12

● 17

.56

.18

25
Table 9. Standard errors of the average Oral Hygiene Index for youths aged 12-17 years by sex,

race. and education of head of household: United States, 1966-70

Race and education of head of household

Totall

None or less than 5 years--------------------------------------

5-7 years------------------------------------------------------

8 years--------------------------------------------------------

9-11 years-----------------------------------------------------

12 years-------------------------------------------------------

13-15 years----------------------------------------------------

16 years-------------------------------------------------------

17 years or more-----------------------------------------------

Unborn --------------------------------------------------------

White

None or less than 5 years--------------------------------------

5-7 years------------------------------------------------------

8 years--------------------------------------------------------

9-11years-----------------------------------------------------

12 years-------------------------------------------------------

13-15 years----------------------------------------------------

16 years-------------------------------------------------------

17 years or more -----------------------------------------------

Unhow --------------------------------------------------------

Negro

None or less than 5 years--------------------------------------

5-7 years------------------------------------------------------

8 years--------------------------------------------------------

9-11 years-----------------------------------------------------

12 years-------------------------------------------------------

13-15 years----------------------------------------------------

16 years-------------------------------------------------------

17 years or more-----------------------------------------------

Unborn --------------------------------------------------------

Both sexes II Boys I

Girls

Standard error

.07

.06

.05

.04

.03

.03

.05

.05

.08

.09

.04

.05

.04

.03

.04

.05

.05

.05

.10

.15

.18

.11

.10

.12

.32

.30

.20

.06

.09

.05

.05

.03

.04

.05

.06

.08

.09

.06

.05

.04

.03

.05

.05

.06

.07

.09

.18

.18

.14

.09

.19

.53

.23

.41

.10

.06

.06

.05

.04

.04

.06

.05

.14

.13

.05

.06

.05

.04

.05

.06

.05

.09

.12

.13

.22

.12

.12

.15

.33

.70

.18

1

Includes all racial groups.

26
Table 10. Standard errors of the average Oral Hygiene Index for youths aged 12-17 years by race

and geographic region: United States, 1966-70

Race and geographicregion

Totall

Northeast------------------------------------------------------

Midwest....-”--------------------..---., -------------------------

South--.,--..---------,---.------”--------------------------------

West-..--..-.,-- ------------------------------------------------

White

Northeast------------------------------------------------------

Midwest--------------------------------------------------------

South-m--..----------”..............----------------------------

West----------------------------- -------------------- --------------

Negro

Northeast------------------------------------------------------

Midwest--------------------------------------------------------

South---------------------------- -----------------------------

West-----------------------------------------------------------

Both sexes Boys Girls

Standard error

.08

.06

.10

.03

.08

.06

.07

.04”

.07

.02

.19

.08

.07

.05

.10

.04

.08 .09

.06 .07

.07 .06

.05 .03

.08

.06

.09

.03

.07 .08

.05 .08

.20 .17

.131 .12

1

Includes all racial groups.

27
APPENDIX I

STATISTICAL NOTES

The Survey Design

The sample design for the first three programs

(Cycles I-III) of the Health Examination Survey has been

essentially similar in that each has been a multi-stage,

stratified probability sample of clusters of households in land-based segments. The successive elements

for this sample design are primary sampling unit,

census enumeration district, segment (a cluster of

households), eligible persons, and finally the sample

person.

The 40 sample areas and the segments utilized in

the design of Cycle III were the same as those in Cycle

II. Previous reports describe in detail the sample design

used for Cycle II and in addition discuss the problems

and considerations given to other types of sampling

frames, cluster versus random sampling, and whether

or not to control the selection of siblings.5

Requirements and limitations placed on the design

for youths in Cycle III? similar to those for children in

Cycle II, were that

. The target population be defined as the civilian,

noninstitutionalized population of the United States,

including Alaska and Hawaii, of ages 12-17 years,

with the special exclusion of youths residing on

reservation lands of the American Indians. The

latter exclusion was due to operational problems

encountered on these lands in Cycle I.

. The time period of data collection be limited to

about 3 years for each cycle and the length of the

individual examination within the specially constructed mobile examination center be between 2

and 3 hours.

. Ancillary data be collected on specially designed

household, medical history, and school questionnaires and from birth certificate copies.

. Examination objectives be primarily related to

factors of physical and intellectual growth and development.

. The sample be sufficiently large to yield reliable

findings within broad geographic regions and popu28

lation density groups as well as age, sex, and limited socioeconomic groups for the total sample.

The sample was drawn jointly with the U.S. Bureau

of Census, starting with the 1960 decennial census

list of addresses and the nearly 1,900 primary sampling

units (PSU’S) into which the entire United States was

divided. Each PSU is either a standard metropolitan

statistical area (SMSA), a county, or a group of two or

three contiguous counties. These PSU’S were grouped

into 40 strata, each stratum having an average size

of about 4.5 million persons, to maximize the degree

of homogeneity within strata with regard to the population size of the PSU’S, degree of urbanization, geographic proximity, and degree of industrialization.

The 40 strata were then classified into four broad

geographic regions of 10 strata each and then within

each region, cross-classified by four population density

classes and classes of rate of population change from

1950 to 1960. Using a modified Goodman-Kish controlled-selection technique, one PSU was drawn from

each of the 40 strata.

Further stages of sampling within PSU’S required

first the selection of census enumeration districts

(ED’s). The ED’s are small well-defined areas of

about 250 housing units into which the entire Nation

was divided for the 1960 population census. Each ED

was assigned a “measure of size” equal to the rounded

whole number resulting from a “division by nine” of

the number of children aged 5-9 in the ED at the time

of the 1960 census. A sample of 20 ED’s in the sample

PSU were selected by systematic sampling with each

ED having a probability of selection proportional to the

population of children 5-9 years at the time of the 1960

census date. A further random selection by size of

segments (smaller c!usters of housing units) within

each ED was then made.

Because of the 3-year time interval between Cycle H

and Cycle III, the Cycle 111frame had to be supplemented

for new construction and to compensate for segments

where housing was partially or totally demolished to

make room for highway construction or urban redevelopment.

Advanced planning for the examinations at the

various locations or stands provided for about 17
days of examinations, which limited the number of

examinees per location to approximately 200. When

the number of eligible youths drawn in the sample

for a particular location exceeded this number, subsampling was done by deleting from the master list

of eligible youths (ordered by segment, household

order within segment, and age within household) every

nth name on the list starting with the yth name, Ybeing a

number between 1 and n selected randomly and n being

the extent of oversampling in the original draw.

In Cycle 111,as in Cycle II, twins who were deleted

in the sample selection were also scheduled for

examination when time permitted, as were those

youths who had been examined in Cycle II.

The sample was selected in Cycle 111, as in

Cycle H, to contain the correct proportion of youths

from families having only one eligible youth, two eligible youths, and so on to be representative of the

total target population. However, since households

were one of the elements in the sample frame, the

number of related youths in the resultant sample is

greater than would come from a design which sampled

youths 12-17 years without regard to household. The

resulting estimated mean measurements or rates should

he unbiased, but their sampling variability will be

sommvhat greater than those from a more costly, timeconsuming systematic. sample design in which every

kth youth would be selected.

The total probability sample for Cycle 111included

7,514 youths representative of the approximately 22.7

million noninstitutionalized United States youths 12-17

years of age. The sample contained youths from 25

different States and approximately 1,000 youths in each

single year of age.

The response rate in Cycle’111 was 90 percent, with

6,768 youths examined out of the total sample. These

examinees were closely representative of the total

sample as well as the population from which the sample

was drawn with respect to age, sex, race, region,

population density, and population growth in area of

residence. Hence it appears unlikely that nonresponse

could bias the findings appreciably.

Reliability

While measurement processes in the surveys were

carefully standardized and closely controlled; the

correspondence between the real world and survey

results cannot be expected to be exact. Survey data are

imperfect for three major reasons: (1) results are

subject to sampling error, (2) the actual conduct of a

survey never agrees perfectly with the design, and

(3) the measurement processes themselves are inexact

even though standardized and controlled.

The report which describes the plan and operation

of Cycle 1113 gives in detail the faithfulness with which

the sampling design was carried out.

Data recorded for each sample child anct youth are

inflated in the estimation process to characterize the

larger universe of which the sample youth is representative. The weights used in this inflation process

are a product of the reciprocal of the probability of

selecting the youth, an adjustment for nonresponse

cases, and a poststratified ratio adjustment which increases precision by bringing survey results into closer

alignment with known U.S. population figures by color

and sex within single years of age 12-17 for the survey

of youths.

In the third cycle of the Health Examination Survey

(as for the children in Cycle II), the samples were the

result of three principal stages of selection—the single

PSU from each” stratum, the 20 segments from each

sample PSU, and the sample youth from the eligible

persons. The probability of selecting an individual

youth is the product of the probability of selection at

each stage.

Since the strata are roughly equal in population

size and a nearly equal number of sample youths were

examined in each of the sample PSUfs, the sample

design is essentially self-weighting with respect to the

target population; that is, each youth 12-17 years had

about the same probability of being drawn into the

respective samples.

The adjustment upward for nonresponse is intended

to minimize the impact of nonresponse on final estimates

by imputing to nonrespondents the characteristics of

“similar” respondents. Here “similar” respondents

were judged to be examined youths in a sample PSU

having the same age (in years) and sex as youths not

examined in that sample PSU.

The poststratified ratio adjustment used in the third

cycle achieves most of the gains in precision which

would have been attained if the sample had been drawn

from a population stratified by age, color, and sex. It

also makes the final sample estimates of population

agree exactly with independent controls prepared by

the Bureau of the Census for the U.S. noninstitutionalized population as of March 9, 1968, (approximate mid-survey point for Cycle III) by color and sex

for each single year of age 12-17. The weight of every

responding sample youth in each of the 24 age, color,

and sex classes is adjusted upward or downward so

that the weighted total within the claas equals the independent population control for each survey.

Sampling and Measurement Error

In this report several references have been made

to efforts to evaluate both bias and variability of the

measurement techniques. The probability design of

the survey makes possible the calculation of sampling

errors. The sampling error is used here to determine

how imprecise the survev test results mav be because

29
Table 1. Number of examined sample youths by receipt of dental examination, sex, and age: Health

Examination Survey, 1966-70

Age

12

13

14

15

16

17

12-17 years -------------------------------

years----------.----.-.-.-..----.--.-.--=----

years-------.-----------------=-=--=-----=---

years ----------------------------------------

years ----------------------------------------

j7ears ----------------------------------------

they come from a sample rather than from the measurements of all elements in theeuniverse.

The estimation of sampling errors fora studyof

the type of the Health Examination Survey is difficult

for at least three reasons: (l) measurement error and

“pure” sampling error are confounded in thedata—it

is not easy to find a procedure which will either completely include both or treat one or the other separately, (2) the survey design and estimation procedure

are complex and accordingly require computationally

involved techniques for the calculation of variancea,

and (3) from the survey are coming thousands of

statistics, many for subclasses of the population for

which there are a small number of cases. Estimates

of sampling error are obtained from the sample data

and are themselves subject to sampling error which

may be large when the number of cases ina cellis

small or even occasionally when the number ofcases

is substantial.

Estimates of approximate sampling variability

for selected statistics used in this report are included

I

Received Did not receive

dental examination dental examination

Total

, ,

II Boys I

Girls I

Boys I

Girls

T

6,768 3,545

1,190 643

1,208 626

1,204 618

1,116 613

1,092 556

958 489

1 II

Number

3,2231 7

I

547

582 i

586

503 i

536 2

469 2

1 ,

4

2

.

-

1

1

in tables 6-10. These estimates have been prepared

by a replication technique which yields overall variability through observation of variabilityamong random

subsamples of the total sample. The method reflects

lmth “pure” sampling variance and a part of the

measurement variance. A similar pseudoreplication

technique8 was used to estimate the standard errors

of the correlation coefficients shown in the Discussion

section.

Bytheend of the surveyofyouthsonly 11 examined

youths had not received adental examination. These 11

examined youths received imputed dental findings. The

imputed values were randomly selected from apoolof

adolescents’ dental records with the same or similar

demographic characteristics. The age-sex distribution

for the 6,757 youths given the dental examination and

the 11 sample youths for whom findings were imputed

are shown in table I. The estimated U.S. population

aged 12-17 years by race, sex, and age is shown in

table II.

Table II. Estimated number of noninstitutionalized youths, by race, sex, and age: United States,

1966-70

Age

12-17 years --------- ---” -------------- ---

12 years ------=-- --------- m------- --------- .-.

13 years-------.--------=----------------------

14 years ---------------------------------------

15 years ........----------------.---...->---------

16 years---------------------------------------

17 years ........-..................------------

30

E3E!aEE

Number in thousands

4,003 1,747

3,952 1,729

3,851 1,686

3,750 1,646

3,625 1,594

3,511 1,528

9,622 1,560 1,580

1,685 285 286

1,667 277 279

1>632 265 268

1,594 254 256

1,542 242 247

1,502 237 244
Table 111. Number of sample youths who received

an imputed (MI-S score by sex and age: Health

Examination Survey, 1966-70

Age Total IIBoys Girls

FIT

Number

J.2-17 years --------- 85 44 41

years ------------------ 15 4 11

years-...--...= . . . . ----

years ------------------ ;; :; z

years ------------------ 4 5

years ------------------ :

years . ----------------- 8 i :

I II I

Of the 6,757 youths who received dental examinations, 85 youths did nothavean OHI-S score. These

85 received an imputed score. The imputed score was

randomly selected from a pool of adolescents’ dental

records with the same or similar periodontal index,

age, race, and family income. The 85 sample youths

for whom an OHI-S waa imputed are shown in table 111

bya.ge and sex.

Tests of Significance

Tests of significance for oral hygiene and periodontal indexes were performed in one of two ways. The

first determined if the difference between two estimated means is equal to or greater than two times

the standard error of the difference. The testassumes,

in accordance with usual practice, that a 68-percent

confidence interval ranges within one standard error

of the tabulated statistics and that a 95-percent confidence interval ranges within two standard errors.

An approximation of the standard errorofthedifference

d =x -y of two statistics x and y is given by the formula

s-d= (s: + s:)% where .sXand s~are standard errors, respectively, of x and y, as shorn” in tables 6-10. For

example, table 2 shows that the mean OHI-S for 12.

year-old youths of all races is 0.94 and 0.82 for 17-

year-old youths of all races, while table 7 indicates

that the standard error for 12-year-old youths is0.03

and that for 17- year -olds is 0.04. The formula yields

an estimated standard error of the difference ( d = 0.13)

of s~=O.05. Hence, as the observed difference is more

than twice its standard error, it can be concluded that

the mean OHI-Sof adolescents aged 12is significantly

higher than that of adolescents aged 17.

The second test isto determine if the difference

between the estimated actual and expected values

is at least two times the standard error of the actual

value. For example, for white youths from families

with less than $3,000 yearly income, the difference

between the actual and expected mean periodontal

scores is 0.31 (table 3) and the standard error is

0.03 (table 8). Since the difference is at least twice

the standard error, it is deemed statistically significant.

The criterion for significance among geographic

regions was more stringent than that for other demographic characteristics. To determine whether

the difference between estimated means for youths

in any two of the four geographic regions was significant, the difference was required to be at least

2.5 times the standard error.

Small Numbers

In some tables magnitudes are shown for cells

for which thesample size is sosmall that the sampling

error may be several times as great as the statistic

itself. Obviously in such instances the statistic has

no meaning in itself except-to indicate that the true

quantity is small. Such numbers, if shown, have been

included in the belief that they may help to convey

an impression of the overall story of the table.

Expected Value

In tables 3-4 the actual mean PI per person is

compared with expected estimates. The computation

of the expected rates was done as follows:

Suppose it is estimated that in a subgroup there

are Ni persons in theithage group (i=l, 2,...6; sum

of Ni=N ). Suppose it is estimated that the mean PI

per person for the United States in the ithage-sex

group is Xi.Then the expected mean PIforthesubgroup is

Comparison of any actual value for, say, an income

group with theexpected value forthat region is undertaken on the assumption that a meaningful statement

can be made which holds, in some average way, for

all youths who are in the family income group. This

may or may not be true. The specified income group

may have higher values for younger youths and lower

values for older youths than those found in other income groups. In that case an average comparison

would obliterate one or both of these differentials.

In arriving at the general conclusions expressed

in the text, an effort was made to consider all the

specific data, including data not presented in this

report, but it must be recognized that balancing such

evidence is a qualitative exercise rather than a quantitative one. The standard error of the difference

between an actual and expected value may beapproximatedby the standard error of the actual value (tables

8-9).

000

31
APPENDIX II

DEMOGRAPHIC AND SOCIOECONOMIC TERMS

Age.—The age recorded for each youth was the age

at last birthday before the date of examination. The age

criterion for inclusion in the sample used in this survey

was defined in terms of age at time of interview. Since

the examination usually took place 2-4 weeks after

the interview some of those who were 17 years old at

the time of interview became 18 years old by the time

of examination. There were 23 such cases. In the adjustment and weighting procedures used to produce

national estimates these 23 were included in the 17-

year group.

Race. —Race was recorded as “white,” “Negro,”

or “other. “ “Other” included American Indians, Chinese,

Japanese, and all races other than white or Negro.

h4exican persons were included with “white” unless

definitely known to be American Indian or of a race

other than white. Negroes and persons of mixed Negro

and other parentage were recorded as “Negro.”

Geographic re~”ono—For purposes of stratification

the United States was divided into four geographic

regions of approximately equal population. These

regions, which correspond closely to those used by the

Bureau of the Census, were as follows:

Region States Included

Northeast ----- Maine, Vermont, New Hampshire,

LMassachusetts, Connecticut,

Rhode Island, New York, New Jersey,

and Pennsylvania

Midwest ------ Ohio, Illinois, Indiana, Michigan,

Wisconsin, Minnesota, Iowa, and

Missouri

South --------- Delaware, Maryland, District of Columbia, West Virginia, Virginia,

Kentucky, Tennessee, North Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana, and Arkansas

West --------- Washington, Oregon, California, Nevada, New Mexico, Arizona, Texas,

Oklahoma, Kansas, Nebraska, North

Dakota, South Dakota, Idaho, Utah,

Colorado, Montana, Wyoming,

Alaska, and Hawaii

Family income. —The income recorded was the

total income of the past 12 months received by the head

of the household and all other household members

related to the head by blood, marriage, or adoption.

This income was the gross cash income (excluding

pay in kind) except in the case of a family with their

own farm or business, in which case net income was

recorded.

Parent. —A parent was the natural parent or, in

the case of adoption, the legal parent of the child.

Guardian. -A guardian was responsible for the

care and supervision of the youth. He (or she) did

not have to be the legal guardian to be considered

the guardian for this survey. A guardianship could

only exist when the parent(s) of the youth did not

reside within the sample household.

Head of household. -Only one person in each

household was designated” as the “head.” He (or she)

was the person who was regarded as the “head” by

the members of the household. In most cases the head

was the chief breadwinner of the family although this

was not always true. In some cases the head was the

parent of the chief earner or the only adult member

of the household.

Education of head of household,—The highest grade

completed in school was recorded. The only grades

counted were those completed in a regular public or

private school in which persons received formal

education, either during the day or night, with either

full-time, or part-time attendance. A regular school

is one which advances a person toward an elementary

or high school diploma or toward a college, university,

or professional school degree. Education in vocational,

trade, or business schools outside a regular school

system was not counted in determining the highest

grade of school completed.

32
APPENDIX Ill

THE DENTAL EXAMINATION

The periodontal disease status and oral hygiene

status of the sample youths who participated in the

health examinations conducted during 1966-70 were

assessed by the Periodontal Index 2 and the Simplified

Oral Hygiene Index? The procedures for scoring and

calculating the two indexes follow.

The Periodontal Index (Pi)

Scores are assigned according to these criteria:

o

1

2

6

8

Negative. There is neither overt inflammation

in the investing tissues nor loss of function due

to destruction of supporting tissues.

Mild gingivitis. There is an overt area of inflammation in the free gingivae, but the area

does not circumscribe the tooth.

Gingivitis. Inflammation completely circumscribes the tooth, but there is no apparent

break in the epithelial attachment.

Gingivitis with pocket formation. The epithelial

attachment has been broken and there is a pock -

et (not merely a deepened gingival crevice due

to swelling in the free gingivae). There is no

interference with normal masticator function;

the tooth is firm in its socket and has not

drifted.

Advanced destruction with loss of masticator. .

function. The tooth may be loose; may have

drifted; may sound dull on percussion with a

metallic instrument.

RULE: When in doubt, assign the lesser score.

Each tooth present in the mouth, unless it is a root,

is scored, and the arithmetic average of all scores is

the individuals PI.

The Simplified Oral Hygiene Index (OHI-S)

Selected surfaces of six teeth are used in making

this estimation of oral hygiene status. For the purposes

of this examination each surface that is used, buccal

or lingual, is considered to encompass half of the

circumference of the tooth. The buccal surface of a

molar, for example, is considered to include half of

the mesial surface and half of the distal.

On both sides of the arch the posterior tooth assessed is the most anterior fully erupted permanent

molar or, in its absence, the most distal fully erupted

primary molar. In most cases this will be a first permanent molar, but in others it may be a first or second

primary molar or a second permanent molar. The

buccal surfaces of upper molars and the lingual of

lowers are examined. In the anterior portion of the

mouth, the labial surfaces of the upper right central

incisor and the lower left central incisor are exam ined.

When these teeth are missing, only the adjacent central

incisor is examined.

Examining for oval debris. —The surface area

covered by debris is estimated by running a number five

explorer along the surface being examined and noting

the occlusal or incisal extent of the debris as it is removed from die tooth surface and adheres to the explorer.

Scores are assigned according to the following

criteria:

o

1

2

3

No debris or stain present.

(a) Soft debris covering not more than the

gingival third of the tooth surface, or (b)

the presence of extrinsic stains without debris

regardless of surface area covered.

Soft debris covering more than one-third but

not more than two-thirds of the exposed tooth

surface.

Soft debris covering more than two-thirds of

the exposed tooth surface.

Examining for oral calculus.-A number five explorer is also used to estimate surface area covered by

supragingival calculus and to probe for subgingival calculus.

Scores are assigned according to the fQIlowing

criteria:

o No calculus present.

1 Supragingival calculus covering not more than

one-third of the exposed tooth surface.

33
2 Supragingival calculus covering more than onethird but not more than two-thirds of the exposed tooth surface, and/or thepresenceofindividual flecks of subgingival calcullis around

thecervical portion of the tooth.

3 Supragingival calculus covering more than twothirds of the exposed tooth surface and~or a

continuous heavy band of subgingival calculus

around the cervical portion of the tooth.

Calculating the index. —The debris scores are totaled and divided by the number of surfaces scored to

obtain the Simplified Debris Index. The Simplified Calculus Index is determined similarly. The debris and

calculus scores are then added to give the Simplified

Oral Hygiene Index.

Training of Examiners

Each of the 6,757 sample youths who received dental

examinations during 1966-70 was examined by one of

seven dentists. The dentists included two senior exTable IV. Percent distribution of differences

aminers, A and B, who trained and supervised the otner

examiners—C, D,E,F,and G.

Sample youths wer~ not assigned randomly or

equally among the various examiners. At most survey

locations youths were examined by only one dentist—

C, D, E, F, or G. At 14 of 40 locations, however, a

small group was examined only by either Aor B. Thus,

the senior dentists examined few sample youths. The

number and percent of youths examined by each dentist

were as follows:

Number Percent

All examiners ------------

A------------------------ ----

B-------- -------- ------------

c

-------- -------- ------------

-------- -------- -------- ----

:----------------------------

F-------- ---------------- ----

G-------- -------- -------- ----

6,757 100.0

236

302 2:;

1,055 15.6

448 6.6

1,689 25.0

1,472 21.8

1,555 23.0

in the Periodontal

dentists and other dentists on replicate

Index (PI) between senior

dental examinations: Health Examination Statistics,

1966-70

Difference in Periodontal Index

Median difference -----------------------------------

Mean difference -------------------------------------

Standard deviation of the difference ----------------

Number of replicate examinations --------------------

All replicate examinations ----------------------

-1.0 or less ----------------------------------------

-o.9------------------------------------------------

-0.8 --------- --------- ----”---- ------------------ ---

-o.7--------------.----------------=----------------

-0.6 ------------------ ---!------ ------------------ ---

-0.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . --------- ------------

-o.4------------------------------------------------

-o.3------------------------------------------------

-0.2 --------- --------- --------- .-----.=- --------- ---

-o.l ------------------------------------------------

0.0 -------- -------- -------- --.----- -------- -.------

+o.l ------------------------------------------------

+0.2 .-----=.- --------- --------- --------- --------- ---

+0.3 --.” ----- --------- --------- --------- ------------

+o.4------------------------------------------------

+o.5------------------------------------------------

+0.6 . . . . . . . . . --------------------------- ------------

+0.7 . . . . . . ..- ------------------ --------- ------------

+0.8 --------- --------- ------------------ ------------

+0.9 . . . . . . . . . ------------------ ---------------------

+1.0 or more ----------------------------------------

C, D,

E, F, G

0.0

-0.01

0.31

407

100.0

;::

0.3

::;

;:;

3.4

1:::

30.4

18.4

7.6

5.2

2.5

i:;

0.5

0.5

0.5

0.3

Examiner

c

- 0%;

0.33

47

D

0.1

0.10

0.17

25

E

0.0

-0.03

0.34

162

Percent distribution

100.0

4.3

-

.

2.i

4.;

1::2

27.6

21.2

4.3

4.3

4.5

2.1

2.1

-

100.0

.

.

24.6

24.0

20.0

1:::

4.0

4.0

.

100.0

2.5

0.6

0.6

0.6

0.;

2.5

3.7

1;:2

33.4

14.8

10.5

03.1

2.5

0.6

0.;

0.6

0.6

0.6

F

I

G

1

0.32

126

100.0

2.4

.

0.;

-

;:!

1::!

11.1

23.0

24.6

6.4

6.4

0.4

M

O.i

0.8

0.19

47

00.0

-

-

2.i

2.1

1!::

8.5

42.6

10.6

4.3

4.3

6.4

-

.

-

-

34
Most examinations completed by the senior dentists

resulted from a planned series of” replicate examinations. AS a rule, the findings of the senior dentists

were included in the sample youthts examination record,

and the findings of the dentist with whom he was paired

were kept separate. The primary aim of the replicate

examinations was to correct any examiner divergence

from the accepted examination procedures.

Throughout the replicate examinations, the senior

dentist completed his examination first, without the other

dentist present, and dictated his findings to a trained

recorder. Then the other dentist completed his examination and the senior dentist recorded the findings.

Appreciable interexaminer differences as well as any

procedure that diverged from the accepted one were

discussed and, if indicated, either resolved or corrected while the sample child was still present. However, the findings originally recorded by the examiner

were not altered.

To indicate the level of agreement on the PI, the

results of the replicate examinations are shown in table

IV. Thb direction of the disagreements that occurred is

shown by positive or negative numbers. A positive

number indicates that a finding of the senior dentist was

lower than that of the other dentist, while a negative

number indicates the opposite.

The data in table IV suggest that the level of examiner agreement between the senior dentists and other

dentists was relatively high. Perfect agreement resulted in 30.4 percent of the examinations and about

62 percent of the periodontal scores differed by no

more than 0.1. Differences greater than 0.3 occurred

in only about 13 percent of the examinations.

Table IV also gives the percent distribution of ~fference between the PI’s assigned by examiners C,

D, E, F, and G individually and those assigned by the

senior examiners. Examiners D and F achieved perfect

agreement less often than

G; but no examiner had an

difference in excess of 0.1.

OHI-S Scores by Examiner

did examiners C, E, and

absolute mean or median

The distribution of the OHI-S scores obtained by

individual dentists in the Health Examination Surveys

of adults in 1960-62, children in 1963-65, and youths

in 1966-70 (table V), gives a basis for roughly asses-.

sing the comparability of OHI-S scoring over the

10-year period. Only the senior dentists, Examiners

1 and 2, were the same during this entire period. Only

one of the other survey dentists conducted examinations

Table V. Cumulative percent distribution of OHI- S scores for children 6-11 years, youths 12-17

yeara, and adults 18-79 years, by apecif ied score and examiner and number of examinees by survey and examiner: Health Examination Surveys, 1963-65, 1966-70, and 1960-62

Survey and OHI- S score

Children 6-11 years (1963-65)

o-------- -------- -.------ -------- ----

0.8 or less --------------------------

1,8 or I.esa --------- --------- --------

2.8 or less --------------------------

Youths 12-17 yeara (1966-70)

o------------------ ------------------

0.8 Or less--------- -----------------

1.8 or less--------------------------

2.8 or less --------- --------- --------

Adults 18-79 years (1960-62)

0.8 or leas --------------------------

1.8 or less --------------------------

2.8 or less --------------------------

3.8 or less --------------------------

4.8 or less --------------------------

children 6-11 years ------------------

Youths 12-17 years -------------------

Adults 18-79 years -------------------

Examiner

All

examiners

1 2 3 4 5 6 7

2;::

78.6

98.2

5%;

92.9

99.0

3!:!

66.0

82.1

92.9

98.3

2.3

29.2

82.3

99.1

3.4

54.0

90.3

98.3

3;:2

68.2

85.2

‘33.;

.

7,096 469

6,765 237

5,382 487

II

Percent of

2!:;

79.1

98.7

4.6

49.8

89.8

98.3

3::!

66.2

84.8

94.0

98.1

2!:2

8001

99.2

12.8

70.1

95.8

99.5

3;::

64.7

81.4

91.8

98.1

examinees

2;::

72.6

95.6

14.7

83.3

97.1

3::$

64.5

79.1

90.1

97.2

12.;

86.0

99.9

6;:;

95.3

99.4

32::

68.8

85.3

97.7

99.9

Number of examinees

397 3,193 2,185 852

303 1,057 450 1,691

467 1,460 1,781 1,187

I I I

5::!

9009

98.4

1,472

61:;

94.0

99.5

1, 55i

—-

35
in more than one survey. “1he two senior dentists

examined only a limited number of persons in moat

survey locations while the other dentists gave most

of the examinations at all but a few locations. No

adjustment has been made in this table for the differences in the age, sex, area, or socioeconomic

background of the examinees which might have contributed to the variation in scoring patterns among

the regular examining dentists.

In the survey of children only 1 percent of all

OHI-S scores were under 0.0 and 22.5 percent were

under 0.9 in contrast with the findings for youths in

which more than 6 percent of the scores were 0.0

and 57.8 percent were under 0.9. Among adults 6

percent of the scores were 0.0, but only 37.5 percent

were under 0.9. In addition it is evident that a much

higher proportion of low scores (less than 0.9) were

given among youtha than among either children or

adults by both senior Examiners 1 and 2, the dentists

who trained all other dentists during the three surveys.

36

ooo —

* U. S. GOVERNMENT PRINTING OFFICE :1975 210-981/5
Series 1.

Series 2.

Sen”es 3.

Sm”es 4.

Series 10.

Series 11.

Series 12.

Series 13.

Sm”es 14.

Series 20.

Sm”es 21.

Sa+es 22.

*

,

!

VITAL AND HEALTH STATISTICS PUBLICATION SERIES

Originally public Health Service Publication No. 1000

pro~ms and collection procedures. —Reports which describe the general programs of the National

Center for Health Statistics and its offices and divisions, data collection methods used, deffnftions,

and other material necessary for understanding the data.

Data evaluation and methods resawch. —Studies of new statistical methodology including experi..

mental tests of new survey methods, studfes of vital statistics collection methods, new analytical

techniques, objective evaluations of reliability of collected data, contributions to statistical theory.

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statistics, carrying the analysis further than the expository types of reports in the other series.

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Data &om the Health Interview Survev. —Statistics on illness, accidental injuries, disability, use

of hospital, medical, dental, and other services, and other health-related topics, based on data

collected in a continuing national household interview survey.

Data from the Health Examination Survey. —Data from direct examination, testing, and measurement of natidttal samples of the civilian, noninstitutional population provide the basis for two types

of reports: (1) estimates of the medically defined prevalence of specific dfseases in the United

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reference to an explicit finite universe of persons.

fkta porn the Institutional Population Surveys. —Statistics relating to the health characteristics of

persons in institutions, and their medical, nursing, and personal care received, based on national

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~ti on health resources: manpower and facdities. —Statistics on the numbers, geographic distribution, and characteristics of health resources including physicians, dentists, nurses, other health

occupations, hospitals, nursing homes, and outpatient facilities.

Data on mortality. —Various statistics on mortality other than as included in regular annual or

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last year of life, medical care during pregnancy, health insurance coverage, etc.

For a list of titles of reports published in these series, write to:

.

Scientific and Technical Information Branch

Nat ional Center for Health Statistics

Public Health Service, HRA

Rockville, Md. 20852

/

I

‘.

-,