Critical evaluation of dental indices

1. Critical Evaluation of Dental Indices
Guided By:
Dr. Girish R. Shavi
Presented By:
Dr. Preyas Joshi
1

2. CONTENTS
Introduction
Objectives of an index
Properties of an ideal index
Purpose and uses of an index
Classification of indices
DMFT index
DMF(S) index
deft index
2

3. 3
Nyvad’s caries diagnostic criteria
Significant caries index (Sic)
Specific caries index
Root caries index (RCI)
Oral hygiene index (OHI)
Oral hygiene index – Simplified
Russell’s periodontal index
CPITN
Community periodontal index
Dean’s fluorosis index
Community fluorosis index
Bibliography

4. 4
Definition1:
“A numerical value describing the relative status of a population on a graduated
scale with definite upper and lower limits, which is designed to permit and
facilitate comparison with other populations classified by same criteria and
methods.”
-Russell A. L.

5. Objectives of an Index1
• To increase understanding of the disease process along with
measurement of the disease prevalence and incidence, thereby
leading to methods of control and prevention.
• It attempts to discover populations at high and low risk, and to
define the specific problem under investigation.
• The results of different populations can be compared.
5

6. Properties of an ideal Index1
 CLARITY: The examiner should be able to remember the rules of
the index clearly in his mind.
 SIMPLICITY: The index should be simple and easy to apply so
that there is no undue time lost during field examinations.
 OBJECTIVITY: The criteria for the index should be objective and
unambiguous(no uncertainty), with mutually exclusive criteria.
 VALIDITY: The index must measure what it is intended to
measure.
 RELIABILITY: The index should measure consistently at
different times and under a variety of conditions. 6

7.  QUANTIFIABILITY: The index should be amenable to statistical
analysis, so that the status of a group can be expressed. by a distribution,
mean, median, or other statistical measure.
 SENSITIVITY: The index should be able to detect clinically relevant but
small shifts, in either direction in the condition.
 ACCEPTABILITY: The use of index should not be painful or
demeaning to the subject.
7

8. Purpose and uses of an index1
• For individual patients:
1. Provide individual assessment to help a patient recognize an oral
problem.
2. Reveal the degree of effectiveness of present oral hygiene.
3. Motivate the person in preventive and professional care for
elimination and control of oral disease.
4. Evaluate the success of individual and professional treatment over
a period of time by comparing index scores.
5. Provide a means for personal assessment by the dental hygienist’s
abilities to educate and motivate individual patients.
8

9. • In research:
1. Determine baseline data before experimental factors are
introduced.
2. Measure the effectiveness of specific agents for the prevention,
control or treatment of oral conditions.
3. Measure the effectiveness of mechanical devices for personal care,
such as toothbrushes, interdental cleaning devices or water
irrigators.
• In Community Health:
1. Show the prevalence and trends of incidence of a particular
condition occurring within a given population.
2. Provide baseline data to show existing dental health practices.
3. Assess the needs of a community.
4. Compare the effects of a community programme and evaluate the
results. 9

10. Classification of indices2
Which is based upon the:
A. Direction in which the scores can fluctuate:
• Irreversible index - DMFT index
measures conditions that will not return to the normal state.
Once established cannot decrease in value on subsequent examinations.
• Reversible index - GI (Loe & Silness)
Index that measures conditions that can be return to the normal state.
Reversible index scores can decrease/increase in value on subsequent
examinations.
10

11. B. The extent to which areas of oral cavity are measured:
• Full mouth index - Dean’s fluorosis index, PI
These indices measure the patients entire dentition/periodontium
• Simplified index - OHI-S (Greene & Vermillion)
These indices measure only a representative sample of teeth.
C. The entity which they measure:
• Disease index - DMF (‘D’ exemplifies a disease index)
• Treatment index - DMF (‘F’ exemplifies a treatment index)
• Symptom index - PBI (papillary bleeding index)
11

12. D. The special categories:
• Simple index – dental caries severity index, Silness and loe plaque index
Index that measures the presence/absence of a condition
• Cumulative index – D MFT index for dental caries
Index that measures all the evidence of a condition, past and present.
12

13. DMFT Index1
• This index was advocated by Henry klein, Carrole E Palmer &
knutson JW in 1938.
• Universally accepted this index is based on the fact that the dental
hard tissues are not self-healing; established caries leaves a scar of
some sort. The tooth either remains decayed or if treated, it is
extracted or filled. The DMFT index is therefore an irreversible
index, meaning that it measures total lifetime caries experience.
• D - Refers to decayed tooth.
• M - Refers to missing due to caries only.
• F – tooth that has been filled due to caries (permanent restorations).
13

14. CALCULATION OF INDEX
Individual DMFT: Total each component D,M and F separately, then
total D+M+F = DMF
Group average: Total the D,M, and F for each individual. Then, divide
the total ‘DMF’ by the number of individuals in the
group.
Percentage needing care: Total No. of decayed teeth * 100
total number examined
14

15. Advantages of the DMFT index
• Caries experience - (past and present) and prevalence of an
individual and community can be found out.
• By using caries experience, oral health status can be estimated
indirectly.
• It gives a broad overview of caries experience in a population over a
period of time.
• D - component gives tooth status affected by dental caries (caries
morbidity)
• M - component gives tooth lost (caries mortality)
• F - component gives the account of fillings done among the
population. 15

16. Limitations of DMFT index
• DMF values are not related to the number of teeth at risk. So, it does
not directly give an indication of the intensity of attack of caries.
• DMF index is invalid in older adults, as teeth can be lost for reasons
other than caries.
• Reaches saturation level at particular point of time when all teeth are
involved and prevents further registration of caries attack even when
caries activity is continuing.
• Cannot be used for root caries.
• Even under extreme conditions, the scores are the same .
• Rate of caries progression cannot be assessed in terms of how fast
caries is progressing or how fast caries has progressed.
• Does not gives the account for treatment needs. 16

17. • Inability of ‘D’ component of DMF score to define treatment needs:
– Criteria used to diagnose caries in a survey are not the same as
those used by practitioners in forming patient’s treatment plan.
– Patient’s own perceived needs, level of interest in their dental
conditions, & ability or willingness to pay all level of treatment.
– A practitioner has to judge whether a minor lesion will develop
into a major lesion over time, and whether a lesion in primary
tooth can safely remain untreated for the life of the tooth. A
survey, whereas, scores a tooth by how it appears at the time of
the survey.
– Treatment philosophies change with time.
– Field surveys can miss early lesions whereas practitioners can
over treat. 17

18. DMF(S) Index1
• When the DMFT index is employed to assess individual surface of
each tooth rather than the tooth as a whole, it is termed as “decayed
missing filled – surface index” (DMFS index).
• The principles, rules and criteria for DMFS index are the same as
that for DMFT index, which is described previously along with
description of DMF index. The only difference is that all surfaces of
tooth are examined.
• Calculation of index:
Individual index
• Total number of decayed surfaces= D
• Total number of missing surfaces = M
• Total number of filled surfaces = F 18
[DMFS Score = D(s)+M(s)+F(s)]

19. • Advantages:
1. More sensitive.
2. More precise.
3. Gives true status of caries attack.
• Limitations:
1. Takes longer time.
2. May require radiographs.
3. The prevalence of caries is expressed as percentage of population
showing any evidence of caries and this measure is useful while
caries is low.
4. Two statistical concepts “experience and incidence”. The sum total
of all decayed, missing and filled teeth or surfaces seen in an
individual nowadays represents dental caries experience. 19
(When compared to DMFT)

20. - It is impossible to tell from this single figure how fast the caries has
occurred or is occurring. Caries incidence, on the other hand, is a
rate and must always be expressed in terms of time. It involves
repeated examinations at regular intervals such as 1 year and is
usually expressed in terms of new findings per unit of time.
5. Dental caries experience is all one can find from the cross-
sectional survey of a group on a single occasion.
6. Incidence is the finding par excellence in a longitudinal survey of
the same individuals at different times. Estimates of incidence can
be made however from cross-sectional surveys for nothing how
much more of the observed condition is found in one age group
than in another.
20

21. Caries index for primary dentition (deft index)1
Given by Grubbel in 1944
• d- decayed primary teeth
• e- primary teeth indicated for extraction /extracted due to caries only
• f- primary teeth with permanent restoration due to caries.
The basic principles and rules for ‘def’ index are the same as that for
DMFT index.
Calculation of ‘def’ index:
For an individual, Total ‘def’ score – d+e+f (max. score – 20)
Total ‘defs’ score – d(s)+e(s)+f(s) (max. score – 88) 21

22. Nyvad’s caries diagnostic criteria3,4
• The Nyvad caries diagnostic criteria was the first classification system to
define clear criteria for the activity assessment of both non-cavitated and
cavitated lesions.
• Given by Bente Nyvad in the year 1999 (Reliability of a new caries
diagnostic system differentiating between active and inactive caries lesions.
Journal of caries research 1999;33(4):252-60)
• Includes manifestation of caries in the initial stages of the disease, even
before a cavity exists.
• Differentiates between active and inactive caries lesions at both the
cavitated and non-cavitated levels.
• It also measures the activity of the carious lesion favoring the cost-benefit
relationship when treatment plans are made.
22

23. Comparison of the New Nyvad Caries Diagnostic Criteria and the deft index
23
Nyvad caries diagnostic criteria deft index criteria

24. Advantages:
– Can identify incipient caries lesion, hence can be used for planning
prevention programmes.
– Underestimation of prevalence and severity of caries with def index
can be omitted as it measures only cavitation state.
– Reduce the need of treatment on a long term basis because diagnosis
of initial lesions can stop the progression of lesion.
Limitations:
– Difficult to make exact diagnosis of precavitated active lesion over
occlusal surface than over facial surface. Physiological wear of
occlusal surface during mastication can lead to disappearance of the
lesions. 24

25. 25
Nyvad’s new caries diagnostic criteria produces values much higher than those with def caries index system.

26. CONCLUSION
• Nyvad’s criteria are a good diagnostic tool that should be used in the
future because it registers the initial stage of the disease, even before a
cavity exists. It also measures the activity of the carious lesion, favoring
the cost-benefit relationship when treatment plans are made.
26

27. Significant caries index5
• Proposed by Bratthall D in 2000
• Using DMF and Sic together helps to highlight oral health in equalities
more accurately among different population groups within the
community in order to identify the need for special preventive oral
health interventions.
• Calculating Sic index:
• Sic is calculated by sorting individuals according to their DMFT
values, than one third of the population with the highest caries score is
selected and the mean DMFT for this subgroup is calculated. This
value is the Sic index.
27

28. • For eg:
Individual DMFT values – 0,0,2,1,0,5,0,14,2,0,3
The sum of the DMFT values: 27
Total No. of individuals: 11
Mean DMFT – 27/11=2.5
How many individuals are there in ‘the one third of the population’:
11/3= 3.666 (The rounded no. of the subgroup: 4)
When the total number of a population cannot be divided by 3, count fractions of .5 and over
as units and cut away the rest.
1/3rd of the population(4) with the highest DMFT values- 2,3,5,14
Sum of the DMFT values in the study subgroup- 2+3+5+14=24
Mean DMFT for this subgroup- 24/4=6
Result: The Sic index of this population- 6.0
28

29. Advantages of Sic over the DMFT index
1. Brings attention to the individuals with the highest caries values in each
population under investigation.
2. It tries to overcome limitations of the mean DMFT value in accurately
assessing the skewed distribution of dental caries in a population
especially in developed countries leading to incorrect conclusion that
the caries situation for the whole population is controlled, while in
reality, several individuals have caries.
Limitations
1. It is just an extension of DMF index as it follows same criteria for
assessing dental caries and will have same limitations in assessing
caries in a population as DMF index.
2. More of significance in population where caries prevalence is low and
has a skewed distribution. 29

30. Specific Caries Index6
• Proposed by Acharya S. in 2006 (Specific caries index: A new system
for describing untreated dental caries experience in developing
countries. J Public Health Dent 2006;66(4):285-7).
• The objective was to develop a reproducible surface-specific caries
index that would provide qualitative and quantitative information about
untreated dental caries, that could be used in conjunction with the
DMFS index and would provide information on not only the caries
prevalence but also the location and type of caries lesion in an individual
based on clinical examination.
30

31. 31
Calculating
Specific Caries
Index
The SCI score for an
individual is
calculated by
adding the
individual tooth
scores.
The SCI scores for
an individual can
range from 0 to 192
(for 32 teeth)

32. Advantages
1. Provides qualitative and quantitative information about untreated
dental caries in an individual or population based on clinical
examination and would provide when used with the DMFS index,
additional data for planning oral health care for a target
population.
2. In a developing country like India, the future manpower and
material requirements and also the type and level of training of
manpower, required to treat the caries in a particular population
might be assessed using the Sci and DMFS scores.
3. The reproducibility and validity of this new index varies from fair
to good (Acc. To authors work results).
32

33. Limitations
1. In cases of large lesions, which cover more than one surface, only
an assumption can be made regarding the originating lesion.
2. Inability of this index, if used alone, to capture information useful
for treatment planning.
3. Lack of provision for assessing root caries.
4. Number of proximal lesions be underestimated in absence of
bitewing radiograph.
33

34. Root caries index1
• Developed by Ralph Katz in 1979.
• Designed specially for analytical epidemiological studies in which risk factors
and causes of disease are studied and analyzed.
• Generally, RCI is used to derive scores for total root caries subtotals in the
mandible and maxilla.
• Formula for calculating RCI: No. of surfaces with root caries lesions * 100
No. of surfaces with gingival recession
• Surface characterization:
M: Missing
NR: No association with gingival recession
R-D: Recession present surface decayed
R-F: Recession present surface filled
R-N: Recession present surface normal
• RCI Score: (R-D+R-F*100) 34/ R-D+R-F+R-N

35. LIMITATIONS
• Root Caries index (RCI) underestimates the prevalence of root caries by
omitting sub-gingival root caries lesions.
• The imprecision of diagnosing gingival recession suggests the need for
improved periodontal diagnostic techniques for the condition of
recession.
35

36. Oral hygiene index (OHI)1
Developed by John C Greene & Jack R Vermillion in 1960.
Calculation:
Debris index(DI): Total debris score recorded
No. of Segments scored
Calculus index(CI): Total calculus score recorded
No. of segments scored
OHI: DI+CI (Range of OHI is from 0-12)
36

37. Advantages
• Sensitive enough to reflect the cleansing efficiency of the tooth-brushing
and the expected relationship between oral cleanliness and periodontal
disease.
• Simple, useful method for assessing a group of individual oral hygiene
status quantitatively.
• Useful tool in programme evaluation in monitoring hygiene
maintenance programmes.
• Can assess individual’s attitude and effectiveness of tooth-brushing in
oral hygiene practices.
37

38. Limitations
• Examination of all surfaces of all teeth present in the mouth (Though
only 12 surfaces are scored), hence requires more time .
• Since it is time consuming, it cannot be used in epidemiological surveys.
• Cannot be used for mixed dentition.
• Inter- and Intra-examiner differences are more.
OHI-S (Oral Hygiene Index-Simplified)1
Given by John C Greene and Jack R Vermillion in 1964. Greene &
Vermillion selected 6 index teeth with selected surfaces that are buccal
surfaces of 16,26 & labial surface of 11,31 whereas lingual surfaces of
36 and 46 which represent all anterior and posterior teeth in each
segment of the mouth are examined.
OHI-S = Debris Index-S+Calculus Index-S 38

39. Advantages
• It is easy to use.
• Requires less time and hence can be used in field studies, sometimes in
selected clinical trials and programme evaluation.
• It may be used as an adjunct in epidemiological studies of periodontal
disease.
• It determines the status of oral hygiene cleanliness in groups.
• Useful in evaluation of dental health education procedures (immediate
and long-term effects).
• Inter- and Intra-examiner errors are less.
39

40. Limitations
• Lacks the degree of sensitivity as much as the original version.
• Underestimation or overestimation of debris and calculus may occur.
• Not appropriate for individual oral hygiene status evaluation.
• Not appropriate for certain types of clinical studies (clinical trials and
research) including detailed investigation of plaque or calculus
formation.
Russell’s periodontal index-19561
• Examination procedure: Every tooth present is scored.
Root stumps are not examined.
40

41. • Scoring criteria & pattern:
Score ‘0’: Negative
Score ‘1’: Mild gingivitis
Score ‘2’: Gingivitis
Score ‘4’: Onset of periodontitis
Score ‘6’: Gingivitis with pocket formation
Score ‘8’: Advanced destruction with loss of masticatory function
Advantages
1. Easy & quickly learned, and is reproducible.
2. Index is simple enough to be practicable under a wide variety of field
conditions.
3. This index measures both reversible and irreversible aspects of periodontal
disease, hence it is known as epidemiologic index with significance.
41

42. 4. Significance of periodontal index is that more data has been assembled using
this index than any other index of periodontal disease.
5. The application and use of Russell’s periodontal index in the past have led to
the development of better understanding of periodontal health status
including research in the present era.
6. Criteria are clear and most of the time in epidemiological studies, results
obtained are comparable.
Limitations
1. In field surveys, carrying radiographic facilities is impracticable and hence
score ‘4’ cannot be used.
2. Index scores from ‘2’ onwards, jump to 4,6 and 8 only to signify the severity
and nature of destruction of periodontium, which are not recordable, and
most of them are irreversible. 42

43. 3. More time consuming.
4. Not sensitive to minor changes in periodontium.
5. No standardized probes are used.
6. It does not give past periodontal disease experience.
Community periodontal index of treatment needs (CPITN)1
Advocated by J Ainamo, Cutress, Barmes, Sardo-Infirri in 1980.
Method of examination:
• The dentition is divided into six sextants consisting of teeth 17-14,
13-23, 24-27, 37-34, 33-43, 44-47.
• Highest score in each sextant is identified after examining all teeth.
• A sextant is examined only if there are two or more functional teeth
present and not indicated for extraction. 43

44. • When only one tooth remains in a sextant it is included in the adjacent sextant.
• In epidemiological surveys the scores are recorded by examination of
specified index teeth.
• Index teeth:
• For adults aged 20 years or more – 10 index teeth
17,16,11,26,27
47,46,31,36,37
• For young adults up to 19 years – 6 index teeth
16,11,26
46,31,36
• Second molars are excluded as index teeth at these ages because of high
frequency of false pockets.
44

45. Advantages
1. When compared to other epidemiological indices for oral health, the
CPITN is simple and more objective in its choice of clinical criteria and
methodology.
2. The data offers rapid appreciation of periodontal condition of a
population, their treatment needs, and personnel required.
3. International uniformity.
4. Treatment needs provide an indication of the level of complexity of
care needed if the periodontal conditions are to improve.
Limitations
1. Does not provide assessment of past periodontal disease experience.
2. Does not record the position of gingival margin, i.e. the degree of
recession, level of alveolar bone.
45

46. 3. Exclusion of important signs of past periodontal breakdown, notably
attachment loss, and mobility.
4. Absence of any marker of disease activity or susceptibility.
5. Underestimation of number of pockets greater than 6 mm in older age
groups.
6. No difference between supra- and sub gingival calculus.
7. No distinction is made between the presence of calculus with or without
bleeding.
8. Validity of CPITN index as a measure of the amount of periodontal care
needed has not been demonstrated.
9. The validity of CPITN- it appears that index underestimates in some areas
and overestimates in others.
46

47. 10. It must be remembers that CPITN is not a research tool but rather a
measure of treatment needs.
11. It should not be used as a measure of periodontitis in research studies.
12. CPITN has been criticized for its measurement of pocket rather than
loss of periodontal attachment.
Community periodontal index (CPI)1
• Introduced in 1994 by WHO.
• Sextants: The mouth is divided into sextants defined by tooth numbers
18-14, 13-23, 24-28, 38-34, 33-43, and 44-48.
• A sextant should be examined only if there are two or more teeth
present and not indicated for extraction.
47

48. • Index teeth:
For adults aged 20 years and above –
17, 16, 11, 26, 27
47, 46, 31, 36, 37
For subjects under the age of 20 years –
16, 11, 26, 36, 31 and 46
Advantages
1. Comprehensive measurement of periodontal disease.
2. Severity of the disease can be measured.
3. Treatment need can be recorded.
48

49. Limitations
1. Time consuming.
2. Calibration will be difficult as CPI involves many criteria.
Dean’s fluorosis index1
Given by Dean in 1942.
Classification:
• Normal – ‘0’
• Questionable fluorosis – ‘1’
• Very mild fluorosis – ‘2’
• Mild fluorosis – ‘3’
• Moderate fluorosis – ‘4’
• Moderately severe fluorosis
• Severe fluorosis – ‘5’
49

50. • Limitations:
• Classification questionable is often a baffling problem
• Again in 1942 Dean modified his index by eliminating moderately severe
fluorosis category.
• The scoring system ranged from ‘0’ (normal enamel) to ‘5’ (Severe fluorosis).
Community fluorosis index1
Dean devised a method for calculating the severity of fluorosis in a community
which is termed as “community fluorosis index” (CFI).
CFI=(n x w) (N), where
n = no. of persons in each category
w = weight of the scale (average score)
N = The total population
50
/

51. • Scoring criteria:
51

52. Advantages:
1. CFI is widely used in epidemiological studies worldwide.
2. It is of value while making comparisons between various studies.
3. It is used to assess the correlation between caries and fluorosis
4. It is also used to assess the severity of fluorosis with level of fluoride in
drinking water.
Limitations:
1. It does not provide information on distribution of fluorosis within the
dentition.
2. Questionable score has created confusion and continues to do so.
3. It is not sufficiently sensitive in its lower scores.
4. Definition of a pitting is necessary as the severe category is not clear in
the 1942 diagnostic criteria. 52

53. Conclusion
• This review found that while new caries detection criteria measured different
stages of the caries process, there were inconsistencies on how the caries
process was measured.
• The future of research, practice, and education in cariology requires the
development of an integrated definition of dental caries and uniform systems
for measuring the caries process.
• Many new indices have been developed to assess caries but we are far away
from finding an ideal caries index which can replace or overcome limitations
of DMF index.
• Some questions which remain unanswered in caries epidemiology are:
1. Is there a need to replace WHO recommended DMFT index especially for
assessing caries in developing countries?
53

54. 2. Should an ideal caries index suggest treatment needs of different caries
stages?
3. What stage of the caries process should be measured; what are the
definitions for each selected stage?
4. What is the best clinical approach to detect each caries stage on different
tooth surfaces?
5. Should the research be separated with regard to find out an ideal coronal and
root caries index?
6. Should separate indices be developed for assessing caries in oral health
surveys and clinical trials?
• At last it is better to say in current scenario it will not be easy to replace
DMFT index as epidemiologists had collected or still collecting lots of data
based upon this index.
54

55. Bibliography
1. Hiremath SS. Indices. In: Hiremath SS. Textbook of preventive and community dentistry.
1st Edition. New Delhi, India: Elsevier; 2007: 179-200
2. Peter Soben. Indices in Dental epidemiology. In: Peter Soben. Preventive and community
dentistry. 4th Edition. New Delhi, India: Arya (Medi) Publishing House; 2010: 311-359
3. M.C. González et al. Comparison of the def Index With Nyvad’s Caries Diagnostic Criteria
in 3- and 4-year-old Colombian Children. Pediatr Dent. 2003; 25(2):132-6.
4. Se´llos MC et al. Reliability of the Nyvad criteria for caries assessment in primary teeth.
Eur J Oral Sci. 2011; 119(3):225-31.
5. Nishi Makiko et al. How to Calculate the Significant Caries Index(SiC Index). WHO
Collaborating Centre, Faculty of Odontology, University of Malmö, Sweden. PDF Vers.
1.0; 2001-03-6
6. Acharya Shashidhar. Specific Caries Index: A New System for Describing Untreated
Dental Caries Experience in Developing Countries. Journal of Public Health Dentistry.
2006; 66(4):285-7
55

56. 56
Sometimes people just need to sleep!!
..Thanks anyways!