Periodontal Indices

1. REFERENCES
1. Ackerman, M. Anne: A clinical study of the Do-
minion electric toothbrush. Typed thesis. Univ. of Mich.
School of Dentistry, Ann Arbor, 1965. p. 86.
2. Greene, J. C: Periodontal disease in India: Re-
port of an epidemiological study. J. dent. Res., 39:302-
312, 1960.
3. Jamison, Homer: Prevalence and severity of per-
iodontal disease in a sample of a population. Typed
thesis. Univ. of Mich. School of Public Health, Ann
Arbor, 1960. 153 p.
4. Ramfjord, S. P.: Indices for prevalence and inci-
dence of periodontal disease. J. Periodont., 30:51-59,
1959.
5. Ramfjord, S. P., Nissle, R. R., Shick, R. A. and
Cooper, H.: Subgingival curettage versus surgical elimi-
nation of periodontal pockets. J. Periodont. (In press).
6. Russell, A. L.: A system of classification and
scoring for prevalence surveys of periodontal disease.
J. dent. Res., 35:350-359, 1956.
7. Smith, W. A. and Ash, M. M., Jr.: A clinical
evaluation of an electric toothbrush. J. Periodont., 35:
127-136, 1964.
The Gingival Index, the Plaque Index and
the Retention Index Systems
BY HARALD LÖE
THE GINGIVAL INDEX (Gl)
The main purpose of creating the Gin-
gival Index system was to introduce a sys-
tem for the assessment of the gingival con-
dition which clearly distinguished between
the quality of the gingiva (the severity of
the lesion) and the location (quantity) as
related to the four (buccal, mesial, distal,
lingual) areas which make up the total cir-
cumference of the marginal gingiva (Löe
and Silness, 1963). At the time the GI was
taken into use the existing index systems,
the PMA index (Massler and Schour, 1949)
with later modifications, the Periodontal In-
dex (Russell, 1957) and the Periodontal
Disease Index (Ramfjord, 1959), did not
fulfill this requirement.
The Gingival Index does not consider
periodontal pocket depth, degrees of bone
loss or any other quantitative change of
the periodontium. The criteria are entirely
confined to qualitative changes in the gin-
gival soft tissue.
Department of Periodontology, The Royal Dental
College, Aarhus, Denmark.
CRITERIA FOR THE GINGIVAL INDEX SYSTEM
0 =
Normal gingiva
1 =
Mild inflammation
—
slight change in
color, slight oedema. No bleeding on
probing
2 =
Moderate inflammation—redness, oede-
ma and glazing. Bleeding on probing
3 =
Severe inflammation
—
marked redness
and oedema. Ulceration. Tendency to
spontaneous bleeding.
Each of the four gingival areas of the
tooth is given a score from 0 to 3; this is
the Gl for the area. The scores from the
four areas of the tooth may be added and
divided by four to give the GI for the
tooth. The scores for individual teeth (in-
cisors, premolars and molars) may be
grouped to designate the GI for the group
of teeth. Finally, by adding the indices for
the teeth and dividing by the total number
of teeth examined, the Gl for the individ-
ual is obtained. The index for the subject
is thus an average score for the areas ex-
amined.
GI = 0 is given to the gingiva the color of
which is pale pink to pink. The
Page 38/610

2. The Gingival, Plaque and Retention Indices Page 39/611
Fig. 1. Normal gingiva. Gingival Index score = 0.
surface after drying is matt. The
degree of stippling may vary. The
gingival margin may be located on
the enamel (Fig. 1) or at various
levels apical to the cemento-enamel
junction. Although the margin
should be thin, the buccal and lin-
gual gingiva may present a rounded
termination against the tooth, there-
by forming the entrance or orifice
of the gingival crevice. The form of
the interdental gingiva depends on
the shape and size of the interden-
tal areas. The tip of the papilla
should be the most incisally or oc-
clusally located part of the gingiva.
On palpation with a blunt instru-
ment (pocket probe) the gingiva
should be firm.
GI = 1 is the score given when the gingiva
is subject to mild inflammation.
The gingival margin is slightly
more reddish or bluish-reddish than
normal and there is slight oedema
of the margin (Fig. 2). A colorless
gingival exudate may be observed
or collected at the entrance of the
crevice. Bleeding is not provoked
when a blunt instrument (pocket
probe) is run along the soft tissue
wall of the entrance of the gingival
crevice.
GI = 2 This is the score for a moderately
inflamed gingiva (Fig. 3). The gin-
giva is red or reddish-blue and
glazy. There is enlargement of the
margin due to oedema. Bleeding is
provoked when a blunt instrument
(pocket probe) is run along the
Fig. 2. Mild gingivitis. Gingival Index score = 1.
soft tissue wall of the entrance of
the gingival crevice.
GI = 3 is the score for severe inflamma-
tion. The gingiva is markedly red
or reddish-blue and enlarged (Fig.
4). Tendency to spontaneous bleed-
ing. Ulceration.
As seen, the decisive criterion in the dif-
ferentiation between the GI = scores 1, 2
and 3 is the various tendencies of the gin-
giva to bleeding: GI = 1 is the score for
the slight change from normal, but the
change is not of the order that bleeding
may be provoked by gentle probing. GI = 2
represents the stage where bleeding may be
initiated by probing and GI = 3 shows tend-
ency to spontaneous bleeding.
Scoring according to this system requires
light, drying of the teeth and gingivae, mir-
ror and a pocket probe. If the gingival con-
dition of mesial, buccal and lingual surfaces
of a full set of teeth (28) are to be exam-
ined, scoring according to the Gingival In-
Fig. 3. Moderate gingivitis. Gingival Index score = 2.

3. Page 40/612 Löe
dex System requires from 2-5 minutes, if
chairside assistance and optimal conditions
are otherwise provided.
A typical examination of all surfaces of
all teeth usually starts with the right upper
second molar, is continued over the midline
to the upper left second molar. On the teeth
of the right side the sequence will be: distal
surface, buccal surface, mesial surface and
on those of the left side: mesial surface, f
buccal surface and distal surface. When
these three surfaces of all teeth have been
assessed, the palatal surfaces of all maxil- n
lary teeth are assessed beginning with the s
upper left second molar. s'
n
Examination of the lower jaw starts with
the lower left second molar and is carried
through to the lower right second molar, ti
On the teeth of the left side the sequence c
will be: distal surface, buccal surface, me- o
sial surface and on those of the right side: ii
Fig. 4. Severe gingivitis. Gingival Index score = 3.
mesial surface, buccal surface and distal
surface. Finally, all lingual surfaces are
scored beginning with the lower left second
molar.
The score for each surface is given to
the recorder. When the three (distal, buc-
cal, mesial) scores for the upper right sec-
ond molar have been recorded, the recorder
indicates to the examiner the next tooth to
Fig. 5. Chart for the recording of Plaque Index, Gingival Index and Retention Index.

4. The Gingival, Plaque and Retention Indices Page 41/613
be examined, for instance by saying: "first
molar," or the number of the tooth. In this
way, a good contact is continuously main-
tained between examiner and recorder (Fig.
5).
Since the gingival area constitutes the
unit the Gingival Index may be scored for
all surfaces of all or selected teeth or for
selected areas of all or selected teeth. It
thus follows that the GI may be used for
the assessment of prevalence and severity
of gingivitis in large population groups as
well as in the individual dentition. Recent
analyses show no difference in the results
when only one of the interproximal surfaces
are examined instead of both, for which rea-
son current examinations have been re-
stricted to buccal, mesial and lingual aspects
of the teeth. However, the score for the one
interproximal surface should be doubled
and the total score for the tooth divided by
four.
Subjects with mild inflammation usually
score from 0.1-1.0, those with moderate in-
flammation from 1.1-2.0, and an average
score between 2.1-3.0 signifies severe in-
flammation.
THE PLAQUE INDEX (Pll)
Recent epidemiological research has es-
tablished that any clinical study with the
aim of evaluating the various etiologic fac-
tors cannot be carried out without taking
into account the gingival deposits and their
possibilities for retention.
Accordingly, the ideal set of index sys-
tems is one which allows the assessment of
the severity of the different factors in the
same area as the gingival condition is re-
corded. Index systems for the recording of
oral hygiene have been proposed by Ram-
fjord (1959) and Green-Vermillion (1960).
The Plaque Index (Pll) is fundamentally
based on the same principle as the Gingival
Index, namely the desirability of distin-
guishing clearly between the severity and
the location of the soft debris aggregates.
The purpose of introducing this system
(Silness and Löe, 1964) was also to create
a plaque index which would match the Gin-
gival Index completely.
CRITERIA FOR THE PLAQUE INDEX SYSTEM
0 =
No plaque in the gingival area.
1 = A film of plaque adhering to the free
gingival margin and adjacent area of the
tooth. The plaque may only be recog-
nized by running a probe across the
tooth surface.
2 =
Moderate accumulation of soft deposits
within the gingival pocket, on the gin-
gival margin and/or adjacent tooth sur-
face, which can be seen by the naked
eye.
3 =
Abundance of soft matter within the
gingival pocket and/or on the gingival
margin and adjacent tooth surface.
Each of the four gingival areas of the
tooth is given a score from 0-3; this is the
Pll for the area. The scores from the four
areas of the tooth may be added and divided
by four to give the Pll for the tooth. The
scores for individual teeth (incisors, pre-
molars and molars) may be grouped to
designate the Pll for the groups of teeth.
Finally, by adding the indices for the teeth
and dividing by the number of teeth exam-
ined, the Pll for the individual is obtained.
P11 = 0 This score is given when the gin-
gival area of the tooth surface is
literally free of plaque. The sur-
face is tested by running a pointed
probe across the tooth surface at
the entrance of the gingival crevice
after the tooth has been properly
dried, and if no soft matter ad-
heres to the point of the probe, the
area is considered clean.
Pll = 1 This score is given when no plaque
can be observed in situ by the
unarmed eye, but when the plaque
is made visible on the point of the
probe after this has been moved
across the tooth surface at the en-
trance of the gingival crevice. Dis-
closing solution has not been used

5. Page 42/614 LÖE
in our investigations, but may be
useful for the recognition of this
film of plaque.
PI I = 2 This score is given when the gin-
gival area is covered with a thin to
moderately thick layer of plaque.
The deposit is visible to the naked
eye.
PI I = 3 Heavy accumulation of soft mat-
ter, the thickness of which fills out
the niche produced by the gingival
margin and the tooth surface. The
interdental area is stuffed with soft
debris.
Thus, the Plaque Index scores consider
only differences as to thickness of the soft
deposit in the gingival area of the tooth
surfaces, and no attention is paid to the
coronal extension of the plaque. PI I = 0 is
the score given when the gingival area of
the tooth surface is literally free of plaque.
PI I = 1 represents the situation where the
gingival area is covered with a thin film of
plaque which is not visible, but which is
made visible. PI I = 2 is the score given
when the deposit is visible in situ and P1I =
3 is reserved for the heavy (1-2 mm. thick)
accumulation of soft matter. The assess-
ment of plaque is made on top of calculus
deposits, on fillings and crowns.
Since the gingival area constitutes the
unit, the Plaque Index may be scored for
all surfaces of all or selected teeth or for
selected areas of all or selected teeth. Con-
sequently, the PI I may be used in large
scale epidemiological investigations as well
as in the examination of smaller groups or
within the dentition of the individual. Re-
cent analyses show no difference in the re-
sults when only one of the interproximal
surfaces are examined instead of both pro-
vided the score is given double load and the
score for the tooth is divided by four.
Scoring according to the Plaque Index
System requires light, drying of the teeth
and gingivae, mirror and a probe. If optimal
conditions and chairside assistance are pro-
vided and all teeth are to be examined scor-
ing according to this system requires ap-
proximately 5 minutes.
The sequence of the examination for
plaque is carried out according to the sys-
tem described for the Gingival Index. When
both GI and P1I are to be used, assessment
of PI I should always precede that of GI.
THE RETENTION INDEX
Recent microscopic and electronmicro-
scopic research has shown that supra- and
subgingival calculus, other rough surfaces
including ill-fitted margins of dental resto-
rations are invariably covered with a non-
mineralized bacterial plaque. This indicates
that these irregular surfaces do not per se
exert a direct mechanical influence on the
gingival tissue, but that mineralized depos-
its, insufficient dental restorations, untreated
carious lesions etc. constitute a group of
retentive elements the rough surfaces of
which provide the possibilities for the bac-
teria to accumulate in the gingival area.
The purpose of creating a Retention In-
dex System (Björby and Löe, 1967) was to
introduce a system for the assessment of
the main retentive factors and which ex-
pressed the quality of the tooth surface (de-
gree of roughness) adjacent to the gingival
tissues. Technically, the Retention Index is
built on principles similar to those under-
lying the Gingival Index and the Plaque
Index.
CRITERIA FOR THE RETENTION INDEX SYSTEM
0 =
No caries, no calculus, no imperfect
margin of dental restoration in a gingi-
val location.
1 =
Supragingival cavity, calculus or imper-
fect margin of dental restoration.
2 =
Subgingival cavity, calculus or imperfect
margin of dental restoration.
3 =
Large cavity, abundance of calculus or
grossly insufficient marginal fit of den-
tal restoration in a supra- and/or sub-
gingival location.

6. The Gingival, Plaque and Retention Indices Page 43/615
discussion
Although Russell's Periodontal Index has
two scores for gingivitis (scores 1 and 2),
this index does not really consider different
qualities of gingival inflammation. The
scores for gingivitis do not refer to various
degrees of severity of the pathological con-
dition, but merely to the horizontal exten-
sion of the marginal inflammation around
the tooth. The P.M.A. index was more or
less based on similar principles.
Ramfjord's Periodontal Disease Index
has three scores for gingivitis (scores 1, 2
and 3). Although these scores do represent
increasing severity of the inflammatory le-
sion (mild, moderate, severe), this part of
the index like that of the Periodontal Index,
at the same time sets definite criteria as to
the extension of the pathological process
along the circumference of the tooth. In
both index systems the individual tooth
represents the unit area.
In order to circumvent the problems of
mixing quality and extension of the dis-
ease, our Gingival Index refers to the indi-
vidual tooth surface as the unit area and,
consequently, the criteria for the different
scores have been made strictly qualitative.
From a fundamental point of view Rus-
sell's Periodontal Index records three cru-
cial stages in periodontal destruction: gingi-
vitis (scores 1 and 2), pocket formation
(score 6) and the almost total breakdown
of the periodontium (score 8). This index
does not differentiate between shallow or
fairly deep pockets, except at the stage
where the tooth is about to lose its function.
In essence, therefore, the Periodontal Index
is a morbidity index which merely answers
yes or no as to whether the tooth has gin-
givitis, pocket formation or has lost its func-
tion due to periodontal destruction. This is
the strength of the Periodontal Index in as-
sessing the overall periodontal disease prev-
alence in large population samples and its
weakness when smaller samples or when the
effect of preventive and therapeutic meas-
ures are to be analyzed.
Ramfjord's Periodontal Index is also a
composite system which records both the
gingival and periodontal situation. In this
system the scores for periodontal destruc-
tion is based on loss of attachment as meas-
ured in millimeter from the cemento-enamel
junction to the bottom of the pocket. If the
loss of attachment measures less than 3 mm.,
the tooth is given an index score of 4, be-
tween 3 and 6 mm. the score is 5, and loss
of attachment of more than 6 mm. scores 6.
Altogether the Periodontal Disease Index
offers greater possibilities than the Perio-
dontal Index for a precise quantitation of
periodontal destruction, and would, there-
fore, seem to be the system of choice in
clinical trials.
The Gingival Index considers only the
state of health of the soft tissues. In our
view there are two good reasons for not ex-
tending a gingival index into a composite
system, which also records the amount of
periodontal breakdown. Firstly, it seems
basically wrong to work two different in-
comparable measures or statistical units
like varying quality and degrees of quantity
into one and the same index system. Sec-
ondly, there appears to be no real need for
transforming pocket depth or loss attach-
ment as based on measurements in milli-
meter to a different system of figures, the
index. It would seem that there is no better
way of expressing quantity of loss of sup-
porting structures than to use the interna-
tionally accepted metric system. Recent
analyses have shown that there is no sys-
tematic error connected with measuring
pocket depth and loss of attachment, and
that the method error in measuring either
one of these parameters is inconspicuous
(Glavind and Löe, 1967).
Therefore, in order to achieve a full
characterization of the periodontal situa-
tion, the quality of the gingiva should be
scored according to the Gingival Index and
the quantity of periodontal destruction
measured in millimeter.
The Gingival Index, the Plaque Index

7. Page 44/616 LÖE
and Retention Index systems constitute a
set of reversible indices which have proved
to be useful instruments in screening the
gingival conditions of children, young and
old adults. The flexibility of the systems
provides the possibility of selecting specified
areas or teeth when a large material is ex-
amined and of utilizing all areas of all teeth
in the examination of small samples. The
sensitivity of and the correspondence be-
tween the different indices have facilitated
the evaluations of various therapeutic and
preventive measures.
The reproducibility is good provided the
examiner's knowledge of periodontal biol-
ogy and pathology is optimal.
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different local factors in the initiation and developmentof periodontal inflammation. Scand. Symp. Periodon-
tology. 1966. Abstr. no. 20. J. Periodont. Res., 2:000,
1967.
Björn, Anna-Lisa, Koch, G. and Lindhe, J.: Evalua-
tion of gingival fluid measurements. Odont. Revy, 16:
300-307, 1965.
Holm-Pedersen, P. and Löe, H.: Flow of gingival
exudate as related to menstruation and pregnancy. J.
Periodont. Res., 2:00-00, 1967.
Koch, G. and Lindhe, J.: The effect of supervised
oral hygiene on the gingiva of children. The effect of
tooth brushing. Odont. Revy, 16:327-335, 1965.
Koch, G. and Lindhe, J.: The effect of supervised
oral hygiene on the gingiva of children. The effect of
sodium fluoride. J. Periodont. Res., 2:000, 1967.
Lindhe, J. and Koch, G.: The effect of supervised
oral hygiene on the gingiva of children. Progression and
inhibition of gingivitis. J. Periodont. Res., 1:260-267,
1966.
Lindhe, J., Koch, G. and Mansson, Ulla, The effect of
supervised oral hygiene on the gingiva of children. The
effect of mouth rinsing. J. Periodont. Res., 1:268-275,
1966.
Löe, H. and Silness, J.: Periodontal disease in preg-
nancy. I. Prevalence and severity. Acta odont. scand.,
21:533-551, 1963.
Löe, H. and Holm-Pedersen, P.: Absence and pres-
ence of fluid from normal and inflamed gingivae. Perio-
dontics, 3:171-177, 1965.
Löe, H., Theilade, Else and Jensen, S. B.: Experi-mental gingivitis in man. J. Periodont., 36:177-187,1965.
Silness, J. and Löe, H.: Periodontal disease in preg-
nancy. II. Correlation between oral hygiene and perio-dontal condition. Acta odont. scand., 22:112-135, 1964.
Silness, J. and Löe, H.: Periodontal disease in preg-
nancy. III. Response to local treatment. Acta odont.
scand., 24:747-759, 1966.
Theilade, Else, Wright, W. H., Jensen, S. B. and
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Periodont. Res., 1:1-13, 1966.