(Reprinted from: Slade GD, ed.

Measuring Oral Health and

Quality of Life. Chapel Hill: University of North Carolina,
Dental Ecology 1997.)

THE ORAL HEALTH

IMPACT PROFILE

Gary D. Slade, B.D.Sc.,

D.D.P.H., Ph.D.

Correspondence to:
Gary D. Slade, BDSc, DDPH, Ph D, Department of Dental Ecology,
University of North Carolina, CB# 7450, Chapel Hill, NC 27599-
7450, USA. Email: gary_slade@dentistry.unc.edu
Oral Impacts on Daily Performances S. Adulyanon; A. Sheiham

B ACKGROUND
The Oral Health Impact Profile (OHIP) was developed with the
aim of providing a comprehensive measure of self-reported
dysfunction, discomfort and disability attributed to oral
conditions. These impacts were intended to complement
traditional oral epidemiological indicators of clinical disease,
thereby providing information about the "burden of illness" within
populations and the effectiveness of health services in reducing
that burden of illness. 1

The OHIP is concerned with impairment and three functional

status dimensions (social, psychological and physical) which
represent four of the seven quality of life dimensions proposed by
Patrick and Bergner. 2 Hence, it excludes perceptions of
satisfaction with oral health, changes in oral health, prognosis or
self-reported diagnoses. Furthermore, the OHIP aims to capture
impacts that are related to oral conditions in general, rather than
impacts that may be attributed to specific oral disorders or
syndromes. All impacts in the OHIP are conceptualized as
adverse outcomes, and therefore the instrument does not measure
any positive aspects of oral health.

D EVELOPMENT OF THE INSTRUMENT

The development of the OHIP followed approaches that had been

used in general health settings to measure the impact of medical
care on functional and social well-being. 3,4 The approach involved
identifying a conceptual model that defined relevant dimensions
of impact then acquiring a broad range of questions and associated
numerical weights which could be combined to create subscale
scores reflecting both the frequency of each impact and lay
judgments about the severity of the impact. The three steps,
which have been described previously, 5 are summarized below.

Conceptual model. Locker's model of oral health 6 was used to define

seven conceptual dimensions of impact: functional limitation
(e.g.,, difficulty chewing), physical pain (e.g.,, sensitivity of teeth),
psychological discomfort (e.g.,, self consciousness), physical
disability (e.g.,, changes to diet), psychological disability
(e.g.,, reduced ability to concentrate), social disability (e.g.,,
avoiding social interaction) and handicap (e.g.,, being unable to
work productively). This model is based on the World Health
Organization's classification 7 in which impacts of disease are
categorized in a hierarchy ranging from internal symptoms,
apparently primarily to the individual (represented in the

2 MEASURING ORAL HEALTH AND QUAL ITY OF LIFE

dimension of functional limitation), to handicaps that affect social
roles, such as work.

Statements about impact. Interviews using open ended questions

with a convenience sample of 64 dental patients were conducted to
identify statements about adverse impacts of oral conditions. The
interviews took place in Adelaide, Australia, among adult patients
at public and private dental care settings. Interviews yielded a
total of 535 statements which were examined for content resulting
in the derivation 46 unique statements that were categorized into
the seven conceptual dimensions. Three additional statements
from an existing inventory 4 were adapted for use in the handicap
dimension.

Weights. Thurstone's method of paired comparisons 8 was used to

generate weights for statements within each conceptual
dimension. Judgments about the perceived unpleasantness of each
impact were recorded by 328 people who were members of
community groups or university students in Adelaide. All
weights were adjusted to positive numbers which ranged from
0.747 to 2.555. Some variation was observed when weights were
computed among sub-groups: for example, in the physical pain
dimension, wearers of full dentures accorded greater weight to
sore spots in the mouth and less to sensitivity of teeth compared
with non wearers of dentures. However, a replication of the
weighting procedure in Canada found that the ranking of OHIP
items made by South Australians were broadly similar to the
rankings made by English-speaking people in Ontario and French-
speaking people in Quebec. 9

Structure of the questionnaire. The OHIP questionnaire consists of

the 49 statements that have been rephrased as questions,
reproduced at the end of this Chapter ( Table 0.2). Respondents are
asked to indicate on a five-point Likert scale how frequently they
experienced each problem within a reference period, for example
12 months. Response categories for the five-point scale are: "Very
often", "Fairly often", "Occasionally", "Hardly ever" and "Never".
Respondents may also be offered a "don't know" option for each
question. For three questions that ask about denture-related
problems (numbers 17, 18 and 30), a response option is provided
for non-wearers of dentures to indicate that these questions do not
apply to them.

Scoring. For data entry, responses are coded 0 (never or not

applicable), 1 (hardly ever), 2 (occasionally), 3 (fairly often) or 4
(very often). "Don't know" responses and blank entries are
entered as missing values, which subsequently are recoded with
the mean value of all valid responses to the corresponding
Oral Impacts on Daily Performances S. Adulyanon; A. Sheiham

question. However, if more than nine responses are left blank or

marked "don't know", the questionnaire is discarded. During data
processing, coded responses are multiplied by the corresponding
weight for each question ( Table 0.2) and the products summed
within each dimension to give seven subscale scores, each with a
potential range from zero (no impact) to 40 (all impacts reported
"very often").

Overall OHIP scores have been computed in two ways. The

simplest method is to count, for each subject, the number of
impacts reported at a threshold level (for example, "fairly often" or
"very often"). In many populations, the distribution of this
summary variable may be skewed, with many individuals
reporting no impact at this threshold, 10 and this may violate
assumptions necessary for some parametric statistical procedures.
The second method of computing an overall OHIP score is to
standardize subscale scores (subtract the sample mean subscale
value from each individual's subscale score and divide the result
by the sample standard deviation for that subscale, creating seven
"z-scores"), and then sum those standardized scores for each
respondent. 5 Typically, the resulting standardized OHIP score has
a better distribution for parametric statistical procedures. 11
However, this second method requires more computer
programming, and the resulting scores have less intuitive appeal
than the simpler count of impacts.

E VALUATION OF THE INSTRUMENT

Reliability of the OHIP was first evaluated among a random

sample of 122 people aged 60+ years who were residents of
Adelaide. 5 Cross sectional results were used to generate Cronbach
alpha coefficients for internal reliability, which ranged from 0.70 to
0.83 for six subscales, but only 0.37 for handicap. Follow-up
administration of the instrument among 46 of those subjects was
used to calculate intra-class correlation coefficients of test-retest
reliability which ranged from 0.42 to 0.77 for six subscales, but
only 0.08 for social disability. In a cross-sectional study of a
random sample of people aged 50+ years in Ontario, Canada,
Cronbach alpha coefficients for all subscales ranged from 0.80 to
0.90.12 In another study of older adults in North Carolina,
reliability was analyzed separately by race (white and black) and
education (<8 years and 8+ years of education) and Cronbach
alpha coefficients for the full 49 -item q uestionnaire were 0.96 or
more for each group. 11

Construct validity was assessed through cross-sectional

comparisons of OHIP responses and related, self-reported

4 MEASURING ORAL HEALTH AND QUAL ITY OF LIFE

 measures. In the study of 122 elderly Adelaide residents, OHIP
subscale scores were greater (P<0.05) among people who perceived
a need for treatment compared with those who did not. 10 There
was a similar association between the total number of OHIP items
and perceived treatment needs in the Ontario study. 12 In addition,
this summary OHIP score had moderately strong, statistically
significant correlations with indices of self reported chewing
(=0.47), self-reported oral pain ( =0.41), other oral symptoms
(=0.34), self-reported problems with eating ( =0.68) and
satisfaction with oral health ( =0.48). Relationships between OHIP
scores and clinical variables (such as missing teeth, decayed teeth
and periodontal destruction) followed hypothesized directions,
although as expected, correlation coefficients were only
moderately strong. 13

F INDINGS FROM THE USE OF THE INSTRUMENT

An example of the distribution of OHIP scores is provided in

Table 0.1 which compares mean subscale scores of dentate and
edentulous people who took part in a study of older adults in two
South Australian cities. 10 Edentulous persons had significantly
higher scores for functional limitation and physical disability,
although not for other subscales. It should be noted that higher
scores for functional limitation, physical pain and physical
disability can be expected for denture wearers because each of
these subscales has one question that applies only to denture
wearers. In this sample, 98 per cent of edentulous people wore
dentures, compared with 55 per cent of dentate persons, which
would account for some of the differences observed in Table 0.1.

Coefficients of variation ( / ) ranged from 0.63 to 2.46 for dentate

people and 1.00 to 3.46 for edentulous ( Table 0.1). In order to
detect a difference of 25 per cent in mean scores for a subscale
with a coefficient of variation of 1.0, some 251 persons per group
would be required to achieve standard type I (0.05) and type II
(0.20) errors.
Oral Impacts on Daily Performances S. Adulyanon; A. Sheiham

Table 0.1: Mean OHIP scores among subgroups of South Australians aged
60+ years
DENTATE EDENTULOUS
(n=905) (n=312)

Subscale mean sd* cv † mean sd cv P-value

Functional limitation 7.91 5.15 0.65 8.67 9.33 1.08 0.04
Physical pain 7.84 4.96 0.63 7.85 7.87 1.00 0.98
Psychological discomfort 5.94 6.38 1.07 5.36 11.30 2.11 0.20
Physical disability 3.60 4.33 1.20 5.58 8.26 1.48 0.01
Psychological disability 3.14 4.79 1.53 3.44 8.24 2.40 0.38
Social disability 1.23 3.03 2.46 1.59 5.50 3.46 0.09
Handicap 1.67 3.31 1.98 1.87 5.69 3.04 0.38

* sd=Standard deviation
† cv=coefficient of variation ( sd/ mean)

Findings from a longitudinal study of 67 elderly South Australians

demonstrated general stability in OHIP scores. 14 Subjects were
asked to complete one questionnaire per month for a 12 month
period. There was a small net increase in the number of items
reported per month (baseline=2.10 items, 12-months=2.15, P=0.83).
Response patterns for all 12 months revealed that only a small
proportion (13.5 per cent) of people displayed an overall trend of
increasing or decreasing impacts, although 47.8 per cent had a
transient fluctuation of at least two items in at least one month.

In studies of independently living older adults, the self-completed

questionnaire has been acceptable to respondents. Response rates
for mail questionnaires with up to two reminder notices typically
ranged from 71 to 86 per cent, although in a study involving
elderly North Carolina blacks, where many survey participants
had difficulty reading, the response rate was only 58 per cent. 11
While a majority of respondents completed all 49 questions
satisfactorily, 43 per cent of respondents in the South Australian
study of older adults had at least one blank entry or "don't know"
response. In those instances, sample mean values for individual
questions were imputed for missing or "don't know" responses
when computing subscale scores, although any questionnaire with
more than nine such responses was discarded . Some seven per
cent of questionnaires were discarded for this reason in the South
Australian study of older adults.

The number of missing items can be reduced with an interviewer-

administered version of the OHIP, although a pilot study revealed
other problems with that format, including interviewer burden

6 MEASURING ORAL HEALTH AND QUAL ITY OF LIFE

 (average time for telephone or face-to-face administration was 17
minutes) and lower levels of test-retest reliability. 15

The substantive findings from the OHIP come primarily from

epidemiological studies which reveal:

 higher OHIP scores among people who have poorer clinical

oral status, as indicated by more missing teeth, more retained
root fragments, more untreated decay, deeper periodontal
pockets and more periodontal recession 11,13,16

 higher OHIP scores among socially and economically

disadvantaged groups, and among people who have infrequent
or problem-motivated dental visits 10,13,14,16

 higher OHIP scores among dental patients with HIV infection

compared with general dental patients 17

 overall stability in OHIP scores for a majority of

independently -living older adults during two-year follow-up
periods 18-20

 increases in OHIP scores during a two-year period for dentate

people who experienced tooth loss 19 and decreases for
edentulous people who received prosthodontic treatment, 21

although the effects were conditional upon baseline oral status

and perceptions of need

A LTERNATE FORMS
A shortened (14-item) version of the OHIP has been developed
from analysis of South Australian data. 22 Work is underway with
French and Spanish forms of the OHIP, although this has revealed
some questions and response categories that could not be
satisfactorily translated.

D ISCUSSION AND EVALUATION

Cross sectional studies that have used the OHIP in various

populations reveal levels of dysfunction, discomfort and disability
that appear consistent with clinical conditions and access to dental
care in those populations. At this descriptive level, the results
reveal some subtle differences in the seven conceptual dimensions
of impact - for example, edentulous So uth Australians had higher
levels of functional limitation and physical disability than dentate
people, while other dimensions did not differ significantly
(Table 0.1). However, there is also a high amount of correlation
Oral Impacts on Daily Performances S. Adulyanon; A. Sheiham

among dimensions, so that statistical associations with impact

appear fairly consistent using either subscales or summary
scores. 11 This is consistent with the finding that all 49 items had
high loadings on a single factor that accounted for 69 per cent of
variation in a principal components factor analysis. 22 This in turn
suggests that, for descriptive purposes, a single-item global
question about oral health related quality of life would capture
many of the same associations that are observed with this more
detailed OHIP questionnaire.

While these cross sectional findings suggest that the OHIP

captures a single dimension of impact, it will be important to
examine data from longitudinal studies and clinical trials in order
to determine if the conceptual dimensions provide information
about subtly different outcomes that are important from a clinical
perspective. Other potential uses for the OHIP should be
investigated, including its potential to identify groups with a high
priority for dental care. Several sub-themes could be investigated:
the ability of the OHIP to identify groups that place a high priority
on their own treatment needs, or that place a high priority on oral
health, or that place a high priority on outcomes of dental care
that increase quality of life. In addition, there is scope for
additional research to investigate how other aspects of quality of
life interact with the dimensions captured in the OHIP. This
research needs to take place within a broader agenda of clinical
and health services research that examines the impact of dental
care on people's well being from a range of perspectives that
include clinical outcomes, satisfaction and quality of life.

R EFERENCES
1. Tugwell P, Bennett KJ, Sackett D, et al. Relative risks, benefits and costs
of intervention. In Warren KS, Mahmoud AAF (editors) Tropical and
geographic medicine. New York: McGraw Hill; 1985; p. 1097-113.
2. Patrick DL, Bergner M. Measurement of health status in the 1990s. Ann
Rev Pub Health 1990; 11:165-83.
3. Gilson BS, Gilson JS, Bergner M, Bobbitt RA, Kressel S, Pollard WE,
Vesselago M. The sickness impact profile. Development of an outcome
measure of health care. Am J Pub Health 1975; 65:1304-10.
4. Hunt SM, McEwan J, McKenna SP. Measuring health status. London:
Croom Helm; 1986.
5. Slade GD, Spencer AJ. Development and evaluation of the oral health
impact profile. Community Dental Health 1994; 11:3-11.
6. Locker D. Measuring oral health: a conceptual framework. Community
Dental Health 1988; 5:5-13.

8 MEASURING ORAL HEALTH AND QUAL ITY OF LIFE

7. World Heal th Organization. International classification of impairments
disabilities and handicaps: a manual of classification. Geneva: World
Health Organization; 1980.
8. Edwards AL. Techniques of attitude scale construction. New York:
Appleton-Century- Crafes Inc. 1957.
9. Jokovic A, Allison P, Locker D, Slade GD. A cross-cultural comparison of
oral health values. J Dent Res 1997; 76(IADR Abstracts):207.
Abstract 1546.
10. Slade GD, Spencer AJ. Social impact of oral disease among older adults.
Aust Dent J 1994; 39:358-64.
11. Slade GD, Spencer AJ, Locker D, Hunt RJ, Strauss RP, Beck JD. Variations
in the social impact of oral conditions among older adults in South
Australia, Ontario and North Carolina. J Dent Res 1996; 75:1439-50.
12. Locker D, Slade GD. Oral Heal th and the quality of life among older
adults: The Oral Health Impact Profile. Can Dent J 1993; 59:830-44.
13. Locker D, Slade G. Association between clinical and subjective indicators
of oral health status in an older adult population. Gerodontology 1994;
11:108-14.
14. Slade GD, Hoskin GW, Spencer AJ. Trends and fluctuations in the impact
of oral conditions among older adults during a one year period.
Community Dent Oral Epidemiol 1996; 24:317-21.
15. Slade GD, Spencer AJ, Keily P. Effects of data collection methods on self-
reported oral health impact. J Dent Res 1992; 71(4):978. Abstract 15.
16. Hunt RJ, Slade GD, Strauss R. Racial variations in social impact among
older community-dwelling adults. J Public Health Dent 1995; 55:205-9.
17. Coates E, Slade GD, Goss AN, Gorkic E. Oral conditions and their social
impact among HIV dental patients. Aust Dent J 1996; 41:33-6.
18. Hunt RJ, Slade GD. Changes in oral impact over two years in North
Carolina elderly. J Dent Res 1995; 74(AADR Abstracts):168.
Abstract 1255.
19. Slade GD, Spencer AJ. Tooth-loss incidence and its social impact among
older South Australians. J Dent Res 74(IADR Abstracts) 1995; 520.
Abstract 956.
20. Slade GD, Locker D. Patterns of change in impact of oral disorders
among seniors. J Dent Res 1993; 72(4):265. Abstract 1294
21. Slade GD, Spencer AJ. Dentures and oral health impact among elderly
edentulous South Australians. J Dent Res 1996; 75 (IADR Abstracts):240.
Abstract 1780.
22. Slade GD. Derivation and validation of a short-form oral he alth impact
profile. [In press] Community Dent Oral Epidemiol.
Oral Impacts on Daily Performances S. Adulyanon; A. Sheiham

Table 0.2: Questions and weights for the Oral Health Impact Profile
Dimen-
sion * Weight Question †

FL 1.253 1. Have you had difficulty chewing any foods because of

problems with your teeth, mouth or dentures?
FL 1.036 2. Have you had trouble pronouncing any words because of
problems with your teeth, mouth or dentures?
FL 0.747 3. Have you noticed a tooth which doesn't look right?
FL 1.059 4. Have you felt that your appearance has been affected
because of problems with your teeth, mouth or dentures?
FL 1.154 5. Have you felt that your breath has been stale because of
problems with your teeth, mouth or dentures?
FL 0.931 6. Have you felt that your sense of taste has worsened
because of problems with your teeth, mouth or dentures?
FL 1.181 7. Have you had food catching in your teeth or dentures?
FL 1.168 8. Have you felt that your digestion has worsened because of
problems with your teeth, mouth or dentures?
P1 1.213 9. Have you had painful aching in your mouth?
P1 0.937 10. Have you had a sore jaw?
P1 1.084 11. Have you had headaches because of problems with your
teeth, mouth or dentures?
P1 1.053 12. Have you had sensitive teeth, for example, due to hot or
cold foods or drinks?
P1 1.361 13. Have you had toothache?
P1 1.088 14. Have you had painful gums?
P1 0.998 15. Have you found it uncomfortable to eat any foods because
of problems with your teeth, mouth or dentures?
P1 1.264 16. Have you had sore spots in your mouth?
FL 1.472 17. Have you felt that your dentures have not been fitting
properly?
P1 1.002 18. Have you had uncomfortable dentures?
P2 2.006 19. Have you been worried by dental problems?
P2 1.902 20. Have you been self conscious because of your teeth, mouth
or dentures?
P2 2.252 21. Have dental problems made you miserable?
P2 1.815 22. Have you felt uncomfortable about the appearance of your
teeth, mouth or dentures?
P2 2.025 23. Have you felt tense because of problems with your teeth,
mouth or dentures?

Continued

10 MEASURING ORAL HEALTH AND QUAL ITY OF LIFE

Table 0.2 continued

Dimen-
sion * Weight Question †

D1 1.109 24. Has your speech been unclear because of problems with
your teeth, mouth or dentures?
D1 1.111 25. Have people misunderstood some of your words because of
problems with your teeth, mouth or dentures?
D1 1.051 26. Have you felt that there has been less flavor in your food
because of problems with your teeth, mouth or dentures?
D1 1.068 27. Have you been unable to brush your teeth properly because
of problems with your teeth, mouth or dentures?
D1 1.266 28. Have you had to avoid eating some foods because of
problems with your teeth, mouth or dentures?
D1 1.022 29. Has your diet been unsatisfactory because of problems with
your teeth, mouth or dentures?
D1 1.351 30. Have you been unable to eat with your dentures because of
problems with them?
D1 1.070 31. Have you avoided smiling because of problems with your
teeth, mouth or dentures?
D1 0.952 32. Have you had to interrupt meals because of problems with
your teeth, mouth or dentures?
D2 1.950 33. Has your sleep been interrupted because of problems with
your teeth, mouth or dentures?
D2 1.393 34. Have you been upset because of problems with your teeth,
mouth or dentures?
D2 1.646 35. Have you found it difficult to relax because of problems
with your teeth, mouth or dentures?
D2 1.936 36. Have you felt depressed because of problems with your
teeth, mouth or dentures?
D2 1.638 37. Has your concentration been affected because of problems
with your teeth, mouth or dentures?
D2 1.437 38. Have you been a bit embarrassed because of problems with
your teeth, mouth or dentures?
D3 1.572 39. Have you avoided going out because of problems with your
teeth, mouth or dentures?
D3 2.555 40. Have you been less tolerant of your partner or family
because of problems with your teeth, mouth or dentures?
D3 1.832 41. Have you had trouble getting along with other people
because of problems with your teeth, mouth or dentures?
D3 2.236 42. Have you been a bit irritable with other people because of
problems with your teeth, mouth or dentures?
D3 1.805 43. Have you had difficulty doing your usual jobs because of
problems with your teeth, mouth or dentures?

Continued
Oral Impacts on Daily Performances S. Adulyanon; A. Sheiham

Table 0.2 continued

Dimen-
sion * Weight Question †

H 2.112 44. Have you felt that your general health has worsened
because of problems with your teeth, mouth or dentures?
H 1.420 45. Have you suffered any financial loss because of problems
with your teeth, mouth or dentures?
H 1.545 46. Have you been unable to enjoy other people's company as
much because of problems with your teeth, mouth or
dentures?
H 1.567 47. Have you felt that life in general was less satisfying
because of problems with your teeth, mouth or dentures?
H 1.879 48. Have you been totally unable to function because of
problems with your teeth, mouth or dentures?
H 1.476 49. Have you been unable to work to your full capacity because
of problems with your teeth, mouth or dentures?

* FL=Functional limitation, P1=Physical pain, P2=Psychological

discomfort, D1=Physical disability, D2=Pscyhological disability,
D3=Social disability, H=Handicap

† Response categories for all questions are: "Very often", "Fairly often",
"Occasionally", "Hardly ever" and "Never". "Don't know" can also be
included as a response category. For questions 17, 18 and 30 a "not
applicable" response is provided to indicate if dentures are not worn.
Instructions to respondents should also indicate the desired time period
(e.g.,. during the last 12 months, during the last month, etc.).

12 MEASURING ORAL HEALTH AND QUAL ITY OF LIFE