What is an index?
○ It is a numerical value.
○ Describing the relative status of a population.
○ On a graduated scale, with a definite upper & lower
limits.

Indices for dental caries
○ I- For permanent teeth:
1- DMF ( DMFT)
2- DMFS
○ II- For deciduous teeth
1- def
2- Its modifications: dmf, df
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Decayed – Missing – Filled Index
DMF
○ Introduced in 1938.
○ Is the most universally employed index for measuring
dental caries.
○ An irreversible index.
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1- DMF
D Decayed tooth.
M Missing due to caries.
F Filled tooth.
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METHOD
○ DMF is only applied for permanent teeth.
○ The teeth not included in the examination are;-
1- Unerupted teeth.
2- Congenitally missing and supernumerary teeth.
3- Teeth removed for other than dental caries
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Priciples and Rules when Recording DMF
1- No tooth be counted more than once.
2- Decayed, Filled and Missed teeth due to caries
should be recorded separately.
3- Filled tooth with recurrent caries recorded as
Decayed.
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4- Deciduous teeth are not included in DMF count.
5- A tooth is considered to be erupted when the
occlusal surface or incisal edge is exposed by
reflecting the overlying gingival tissue.
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WHO modification of DMF Index (1986)
1- All third molars are included.
2- Temporary restorations are considered as D.
3- Only carious cavities are considered as D.
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The DMF INDEX
Expresses the sum of decayed
(D), missing due to caries(M), and
filled (F) teeth per person.
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Scoring:
○ Sound tooth 0
○ D 1
○ M 1
○ F 1
○ The total score = D+M+F
○ It ranged from 0 to 32 in a whole number.
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scored
scored
scored
scored

An example
○ A person with one decayed tooth, two
missing teeth due to caries , and one
filled tooth
DMF = 1 + 2 + 1= 4
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D M F

For a Group of Persons
○ The average number (mean) of DMF =
Sum of DMF of all persons
Number of examined persons
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An example:
○ 5 persons with DMFT ;
3,0, 6, 2, 7
3+0+6+2+7
○ Mean DMFT=
5
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= 3.6

If a carious tooth (D) has more than
one lesion , still only one score will be
given.
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One
carious
surface
two
carious
surfaces
three
carious
surfaces

To overcome this disadvantage
we use
2 - DMFS
○ Tooth Surfaces are counted instead of teeth.
○ It is a sensitive index.
○ Used in clinical trial.
○ DMFS is calculated as for DMFT.
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DT = 1
DS = 2
DT = 1
DS = 3
DT = 1
DS = 1
16
*

d decayed tooth indicated for
filling.
decayed tooth indicated for
extraction.
filled tooth
17
*
f
e
II- For Deciduous Teeth

○ Missing decidious teeth due
to caries are not recorded.
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m
extracted
Naturally
exfoliated
?
?

Modifications of def index
19
*
dmf
index
df
index
Before age of exfoliation.
Only for 1ry molars
= def
Does not allow for 2 grades
of caries.
d + e = d

Mixed dentition
○ DMFT or DMFS and deft and defs are never added
together.
○ The index for the permanent teeth is usually determined
first then for primary teeth.
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Evaluation Of DMF Index
○ Advantages
1- It is the only comprehensive index to date to measure
dental caries.
2- It is applicable to most age groups.
3- It is very high inter and intraexaminer agreeability.
4- Is the best method to asses treatment need.
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5- Gives an analyses of the following:-
a- Decayed – request for service provider.
b- Missing – tell the negligence of the people.
c- Filled – tell about the services utilized
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Limitations of DMF index:
1- DMF score is a simple count. It has no
denominator indicating the number of teeth at
risk.
2- DMF index gives equal scores to missing,
untreated decayed, or well restored teeth.
3- DMF index is invalid when teeth have been
lost for reasons other than caries.
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4- DMF index can overestimate caries
experience by including for ex. Teeth with
“preventive restoration”.
5- DMFS index cannot account for sealed teeth.
To do this ,the DMFS would then become
DMFSS.
6- DMF index is not recommended for measuring
root caries.
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Measurements of root caries
Root lesions
characterized by being:
○ Small , disconnected
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○ Lesions occur on exposed roots.
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Teeth with gingival recession

Root caries can be measured
by:
1- Simple prevalence (proportion/percentage).
2- Number of carious and restored root lesions per
person.
3- ROOT CARIES INDEX (RCI)
○ Number of missing teeth per an individual should
be recorded in a separate figure with any of the
previous 1,2,or 3.
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○ It is first described in 1980.
○ Scoring is restricted to teeth at risk.
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○ At risk tooth for root caries is that tooth with gingival
recession, i.e. part of cemental surface has exposed to
oral environment.
29
*

The is calculated as
follows:
decayed + filled root surface
=
root surface with loss of periodontal attachment:
decayed + filled + sound
* 30
X 100

For
example:
○ If we have 100 teeth with gingival recession
(for a group of population) , only 9 teeth were
decayed or filled on root surfaces.
= 9%
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References
• Burt AB, Eklund SA. Dentistry, Dental Practice and the Community.
6th Ed 2005, W. B. Saunders Company, Chapter No.15. P.P 194-202
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