INDICES

Index is defined as 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 its comparison with other population classified by the same criteria and

methods.

Given by RUSSEL.A.L. in 1969.

INDICES

OBJECTIVES:

1.Increase understanding of the disease process.

2. To discover population at high and low risk.

3.To define the specific problem under investigation.

IDEAL REQUISITES OF AN INDEX

1.Clarity,simplicity and objectivity.2.Validity3.Reliability4.Quantifiability5.Sensitivity.6.Acceptability

CRITERIA FOR SELECTING AN INDEX

1.Simple to use and calculate.2.Should permit the examination of many

people in a short period of time.3.Should require minimum armamentarium and

expenditure.4.Criteria should be clear and readily

understandable.5.Free from subjective interpretation.

6.Should define clinical conditions objectively.7.Should be highly reproducible.8.Should have validity and reliability.9.Should be equally sensitive throughout the

scale if relates to severity of variable.10.Should not cause discomfort to the patient

and should be acceptable to the patient.

Based upon the direction in which their scores can fluctuate,indices are classified as either reversible or irreversible.

REVERSIBLE

Index that measures conditions that can be changed. Reversible index scores can increase or decrease on subsequent examinations. Eg:Indices that measure periodontal conditions.

CLASSIFICATION OF INDICES

IRREVERSIBLE Index that measures conditions that will not

change. Irreversible index scores, once established cannot decrease in value on subsequent examinations.

Eg. An index that measures dental caries

Depending upon the extent to which areas of oral cavity are measured. Indices are classified into ‘Full mouth’ or ‘simplified’

FULL MOUTH

These indices measure the patient’s entire periodontium or dentition.

Eg:Russel’s Periodontal index SIMPLIFIED INDEX

These indices measure only a representative sample of the dental apparatus.

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

Indices may be classified in certain general categories according to the entity which they measure like:

a) Disease indexb) Symptom indexc) Treatment indexThe D(decay) portion of the DMF index best

exemplifies a disease index.The indices measuring gingival/sulcular bleeding

are essentially symptom indicesThe F(filled) portion of the DMF index best

exemplifies a treatment index.

In general there are two types of dental indices.

The first type of index measures the ‘number’ or ‘proportion’ of people in a population with or without a specific condition at a specific point in time or interval of time.

The second type of dental index measures the ‘number’ of people affected and the severity of the specific condition at a specific time or interval of time.

Dental indices can also be classified under special categories as:

SIMPLE INDEXIndex that measures the presence or absence of

a condition.Eg: An index that measures the presence of

dental plaque without an evaluation of its effect on gingiva.

CUMULATIVE INDEXIndex that measures all the evidence of a

condition, past and present.Eg: DMF index for dental caries

INDICES USED FOR ASSESSMENT OF DENTAL

CARIES

It is defined as a progressive,irreversible, microbial disease affecting the hard parts of the tooth exposed to the oral environment,resulting in demineralization of the inorganic constituents and dissolution of the organic constituents thereby leading to a cavity formation

DENTAL CARIES

As early as 1931,Bodecker CF and Bodecker HWC described a caries index.this index was found to be sensitive but too complex for use in epidemiological surveys

Bodecker modified this caries index later,where,in addition to counting the surfaces decayed,an extra count was allotted for those surfaces that could experience multiple carious attacks.but this was also not used in major epidemiological studies

HISTORICAL BACKGROUND ON CARIES INDICES

The approach to measuring caries by counting the numbers of teeth in the mouth visibly affected by caries was used in a systemic manner,by Dean HT & associates in their historic studies of the dental caries/ fluoride relation

Mellanby M in 1934 described the carious lesions depending upon the degree of severity and numerically expressed it as follows:

1-slight caries2-moderate caries3-advanced caries

DECAYED MISSING FILLED CARIES INDEX (DMF CARIES INDEX)

MEASURING DENTAL CARIES FOR PRIMARY TEETHSTONE’S INDEXCZECHOSLOVAKIAN CARIES INDEX (CCI)CARIES SUSCEPTIBILITY INDEXDMF SURFACE PERCENTAGE INDEX (DMFS PI)RESTORATIVE INDEX (RI)MODIFIED DMFT INDEXCARIES SEVERITY INDEX (Csi)FUNCTIONAL MEASURE INDEX (FMI)TISSUE HEALTH INDEXDENTAL HEALTH INDEX (DHI)SIGNIFICANT CARIES INDEXROOT CARIES INDEX (RCI)

Introduced by Henry Klein , Carole E Palmer and Knutson J W in their studies of dental caries in Hagerstown,Maryland in 1938.

Irreversible index,applied only to permanent teeth

D-decayedM-missingF-filledAlways signified by upper case letters (capital

letters)

DECAYED,MISSING,FILLED CARIES INDEX (DMF CARIES INDEX)

Can be applied to whole teeth (DMFT) or to surfaces (DMFS)

DMFT:Purpose: To determine total dental caries

experience, past & presentBased on 28 teethTeeth not counted: Third molars Unerupted teeth Congenitally missing & supernumerary teeth Teeth removed for reasons other than dental caries such as

orthodontic treatment or impaction Teeth restored for reasons other than dental caries such as

trauma (fracture) cosmetic purposes or for use as a bridge abutment

Instruments used are plain mouth mirror and explorer.

Criteria to identify caries is 1) Lesion clinically visible.2) Catch to the explorer tip.3) Explorer tip can penetrate deep into the soft

yielding tooth material.4) Discoloration or loss of translucency typical

of demineralized or undermined enamel.

RULES OF DMFT:

No tooth should be recorded more than once,either decayed ,missing or filled teeth.

Decayed, missing and filled teeth should be recorded separately.

Secondary caries below the filling should be counted as decayed.

Teeth missing only due to caries should be counted as missing & also those which are indicated for extraction

Unerupted teeth,missing due to accident, congenitally missing,tooth extracted for orthodontic reasons are not counted as missing

A tooth which is restored separately on different surfaces should be counted only once as filled tooth.

A tooth which is decayed as well as filled is considered as decayed.

Deciduous teeth should not be counted.A tooth is considered to be erupted when the

occlusal surface or incisal edge is totally exposed.

A tooth is considered to be present even though the crown has been destroyed and only the roots are left.

The DMF score for an individual can range from 0 to 28,in whole numbers

A mean DMF score for a group,being the total of individual values divided by the number of subjects examined,can have fractional values

DMFS:Purpose: to determine total dental caries

experience,past and present,by recording tooth surfaces involved instead of teeth as in DMFT

Principles, rules and regulations are the same as that of DMFT

Surfaces examined Anterior teeth -four surfaces Labial, lingual, mesial, distal (12 X 4 = 48)Posterior teeth-five surfacesFacial,lingual,mesial,distal & occlusal (16 X

5=80)

W.H.O MODIFICATIONS(1986)

1) All third molars are included.2) Temporary restorations are considered as ‘D’3) Only carious cavities are considered as ‘D’

LIMITATIONS OF DMFT INDEX:

1)DMF values are not related to the number of teeth at risk.

2)DMF can be invalid in older adults because teeth can become lost for reasons other than caries.

3)DMF index can be misleading in children whose teeth have been lost due to orthodontic treatment.

4) DMF index can overestimate caries experience in teeth in which preventive filling have been placed.

5)DMF index is of little use in studies of root caries.

-Half mouth checking technique-Half the upper arch is scored and then the contra lateral lower arch half scored and the

result doubled.

W.H.O.-SHORT HAND METHOD OF DMFT

index for measuring caries in primary dentition is the def index described by Grubbel in 1944

d-decayede-indicated for extractionf-filledTeeth missing due to caries are not recorded

because of the difficulty,in many children,of distinguishing between extracted and naturally exfoliated primary teeth

MEASURING DENTAL CARIES FOR PRIMARY DENTITION

Modification of the index: dmf for use in children before ages of

exfoliation dmf applied only to the primary molar teeth df index in which missing teeth are ignored

deft & defs: Purpose:to determine the dental caries

experience as shown by the primary teeth present in the oral cavity

Teeth not counted:Missing teeth including unerupted &

congenitally missingSupernumerary teethTeeth restored for reasons other than dental

caries are not counted as f dmf:For children over 7 years and upto 11 or 12

the decayed,missing & filled primary molars and canines have been used to determine a dmft or dmfs.A primary molar or canine is presumed missing because of dental caries when it is missing before the normal exfoliation time

dft and dfs: In the deft and defs as described, both ‘d’ and

‘e’ are used to describe teeth with dental caries. Because of that ‘d’ and ‘e’ are sometimes combined and the index becomes the dft and dfs

DMFT and DMFS and a deft or defs are never added together. A separate index for permanent teeth and for primary teeth is given. The index for permanent teeth is usually determined first, and then the index for the primary teeth

Developed by Stone H.H.,Lawton F.E,Bransby E.R & Hartly H.O in 1949

Scoring criteria: 1-one point to one or more cavities in the same

tooth detectable by sharp probe where the lesion has not penetrated through the enamel to involve the dentine

2-two points to one or more cavities in the same tooth where the dentine is involved,where a total of less than a quarter of crown is estimated to have been destroyed

3- three points to one or more cavities in the same tooth resulting in a total destruction of more than a quarter of the crown

STONE'S INDEX

Introduced by Poncova,Novak and Matena in 1956

Mainly used to compare caries experience in one group with that of the other groups with similar population density but living in different environments

Formula: 1-C-FC-4/5E-2/3AT ----------------------------- base

(C-caries,FC-fillings & crowns,E-extractions,AT-anchorage teeth)

CZECHOSLOVAKIAN CARIES INDEX

The proposed formula can be applied as a basis for an individual or a collective index

In individual examination,the base is given by the amount of teeth in adult dentition and in collective studies,the base is the number of persons examined multiplied by 32 to establish the correct base figure

The average index value will then be between 0 to 1

The nearer,the index is to 1,the higher the caries frequency

Developed by Richardson A. in 1961,for assessing caries caries susceptibility

Based on Bodecker and Mellanby caries indices

2 factors involved:a) Amount of tooth surface at riskb) Amount of caries developing during the

period of observation‘b’ divided by ‘a’ gives a measure of

susceptibility

CARIES SUSCEPTIBILITY INDEX

Method:Each tooth is divided into various surfaces,to

use one caries tooth surface as the unit of measurement

Susceptible surfaces are scored as follows:Incisors = 4Canine = 4Premolar = 5Molar = 5Full permanent dentition has 148 susceptible

surfaces Full deciduous dentition has 88 susceptible

surfaces

Each individual is examined initially & caries and restored surfaces are noted.The number of susceptible surfaces is calculated.

Each tooth surface which is caries free and had not been restored is considered susceptible

Reexamined after 12/6 months & caries developed in each surface is noted.Caries score is calculated

Caries score/number of susceptible surfaces gives a ratio known as ‘susceptibility ratio’(SR)

Susceptibility index=SR X 100Expressed as a percentage

Developed by Jager C.L. in 1963Method:All the teeth are given surface values;The incisors and canines are given ‘four’

valuesPremolars and molars are given ‘five’ values

Deciduous and permanent teeth are treated alike and a mixed dentition does not upset the DMFS percentage index

D-M-F SURFACE PERCENTAGE INDEX

Caries teeth are allotted ‘one’ carious surface value for every surface attacked by caries

Missing teeth are allotted surface values equivalent to their total surface values. Missing teeth lost,other than caries is not included

Restored teeth are treated as carious teeth Interproximal cavities of incisors are given

‘three’ carious surfaces value because they usually affect three surfaces

Interproximal surface of a premolar or molar is allotted ‘two’ carious surface values

The age of the subject is considered,since different numbers of surfaces are present at different ages

The simplified age factors for different age groups are as follows:

6 to 71/2 months 67 to 9 months 312 to 14 months 216 to 18 months 1.520 months to 5 years 16 to 11 years 0.912 to 16 years 0.817 years 0.7

Calculation:To determine the DMFS percentage caries

index of an individual,total the carious surface values and multiply by the age factor for the particular individuals age group.

Developed by D. Jackson in 1973RI=F/F+DMeasures the proportion of attached

teeth(F+D) which are filled(F)Does not depend on DMF index & hence can

be used at all agesRI is not a weighted index,it is a simple

proportion with a definite meaning

RESTORATIVE INDEX

It is the objective of the unmet restorative treatment needs (UTN) used by Glick et al in 1972,which is D/F+D%

The restorative index as a community index: The RI can be used to measure the level of

restorative care in any community and for any subsection of a community at any age

MODIFIED DMFT INDEXProposed by Joseph Z. Anaise in 1984Enables one to obtain a more complete

measure of caries experience & avoids the loss of information such as the extent of restorations in teeth having,carious lesions. In doing so,a more detailed account of the population’s dental needs is recorded at no additional cost and without using additional index

Follows the same procedure as DMFT index. However,the modification involves the division of ‘D’ component into four separate categoriesas:

C- unfilled teeth that are cariousCF- restored teeth that are either secondarily

carious around the margins of restorations or primary on a tooth surface rather than the restored one

IX- carious teeth either filled or unfilled that in the examiners opinion are indicated for extraction i.e. caries have so destroyed the crown that it cannot be restored;only the root remain

IRC- carious teeth either filled or unfilled that in the examiners opinion are indicated for pulp treatment or root canal treatment

The remaining two categories of DMFT index are scored as usual

The DMFT score is then the summation of all six categories

The D1-D3 Scale was first published by WHO in 1979 as an aid to diagnosing coronal caries

Traditionally used among european investigators who diagnose dental caries from the earliest detectable noncavitated lesion through to pulpal involvement

Said to be of extreme value in research studies because it permits identification of lesion progression as well as initiation

DENTAL CARIES SEVERITY CLASSIFICATION SCALE

0-surface sound: no evidence of treated or untreated clinical caries

D1-initial caries:no clinically detectable loss of substance For pits & fissures,there may be significant staining, discolouration, rough spots in the enamel that do not catch the explorer but loss of substance cannot be positively diagnosed. For smooth surfaces,there may be white opaque areas with loss of luster

D2-Enamel caries:demonstrable loss of tooth substance in pits,fissures or on smooth surfaces,but no softened floor or wall or undermined enamel. The texture of the material within the cavity may be chalky or crumbly,but there is no evidence that cavitation has penetrated the dentin

D3-caries of dentin:detectably softened floor, undermined enamel or a softened wall, or the tooth has a temporary filling. On approximal surfaces,the explorer point must enter a lesion with certainty

D4-pulpal involvement:deep cavity with probable pulpal involvement.pulp should not be probed (usually included with D3 in data analysis)

Involves a lengthy & detailed examination,requires meticulous examiner training

Said to be valuable for research studies but there is less consensus within the research community on its use in large-scale surveys

Developed by Tank Certrude & Storvick Clara in 1960

Developed to study the depth & extent of the caries surfaces & the extent of pulpal involvements based on clinical and radiographic examinations

Scoring criteria: 1-superficial (caries in enamel) 2-moderate (caries in enamel and superficial

dentine) 3-moderately severe(enamel undermined) 4-severe(approaching pulp,enamel collapsed) 5-pulpitis(caused either by deep seated caries or

by trauma without caries)

CARIES SEVERITY INDEX

6-death of pulp(caused either by deep seated caries or by trauma without caries)

7-periapical infection( caused either by deep seated caries or by trauma without caries)

DENTAL CARIES SEVERITY INDEX FOR PRIMARY TEETH

Proposed by Aubray Chosack in 1986Developed for primary teethCriteria for scoring:A. occlusal surfaces & pit and fissure caries on

buccal or palatal surfaces of molars1-early pit and fissure caries where explorer

catches or resists removal with moderate or firm pressure, and is accompanied by either a softness at the base of the areas or an opacity adjacent to the pit or fissure as evidence of undermining or demineralization or softened enamel adjacent to the pit or fissure which may be scraped away with the explorer

2-cavitation of atleast 1mm across the smallest diameter at the tooth surface

3-cavitation with breakdown or undermining (as seen by obvious discolouration) of atleast half a cusp

B. Buccal,lingual and palatal smooth caries1-a white lesion not extending to the

embrassure areas,found to be soft and sticky by penetration with the explorer

2-cavitation of atleast 1mm but less than 2mm across the smallest diameter, or a soft sticky white lesion extending into one embrassure

3-cavitation of atleast 2mm in the smallest diameter or a soft sticky white lesion extending into both embrassures

C. proximal surfaces of molars1- a discontinuity of the enamel in which an

explorer will catch and there is softness2-cavitation with early breakdown of marginal

ridge or obvious discolouration indicating undermining of the ridge

3-breakdown of the marginal ridge with cavitation extending to mesial or dental extensions of occlusal fissures

*in cases of proximal caries ‘3’ this will not count as occlusal caries unless the caries extends past the distal or mesial extensions of the fissures;in which case occlusal caries will be scored as in section ‘A’

D. Proximal surfaces on incisors and canine1- a discontinuity of the enamel in which an

explorer will catch and if there is softness2-cavitation with breakdown or obvious

discolouration, indicating undermining for atleast 1mm on the buccal or lingual surfaces

3-cavitation with breakdown of incisal edge or undermining of the edge is indicated by obvious discolouration

Caries seen on the buccal,lingual and palatal surfaces in all teeth continous with occlusal or proximal caries is only scored for these surfaces when normal pits or fissures of these surfaces are affected or included, or when the caries extends along atleast half the gingival third of these surfaces

Only the largest caries involment is scored for any one surface. Scores of two or more lesions on one surface are not combined

A filled surface is given a score of 1, secondary caries at the margin of restoration is given a score of 2

A full crown restoration gives a total score of 5 for that tooth and the total tooth score of 6 is given to a tooth extracted because of caries.

These scores are based on the clinical experience of the earlier levels of caries severity resulting in these types of treatment

Score for each tooth is total of the scores of all the surfaces.

Although a theoretical score of 15 is possible for molars and 12 for canines and incisors,part of the tooth material loss may have occurred because of fracture of unsupported surface,rather than caries of that surface.

Thus a maximum of 12 is scored for molars and a maximum of 9 for canines and incisors

If caries has resulted in complete breakdown of the crown,leaving only roots,the maximum score is recorded for this tooth

The Csi for the population is the mean of the scores for the caries teeth.teeth free of caries are not included in this calculation

Proposed by Shetham A.,Joan Maizels and Alfred Maizels in 1987

Modification of the DMFT indexThe filled and sound teeth are weighed

equally,but the decayed and missing are given zero weight

Calculated by adding the filled and sound teeth and then dividing by total number of teeth present i.e. 28 (excluding third molar)

FMI=Filled + Sound/28FMI Score ranges from 0 to 1

FUNCTIONAL MEASURE INDEX

Developed by Sheiham A.,Maizels J. and Maizels A. in 1987 as the second alternative indice

( modification of DMFT index)Assess the dental health status rather than

cariesRepresents the total amount of sound tooth

tissue at a given point in timeDefined as the weighted average of decayed

teeth,filled teeth & sound teeth THI=1/4 (1*decayed +2*filled +4* sound)/28Third molars are excludedScores range from 0 to 1

TISSUE HEALTH INDEX

Developed by Carpay J.J.,Nieman F.H.M,Konig K.G, Felling A.J.A, and Lammers J.G.M in 1988

Developed to maximize the difference between sound and affected teeth

The sound teeth were given a score of ‘+1’The affected teeth were given a score of ‘-1’ (Sound teeth)-(Decayed+Filled+Missing teeth) DHI= --------------------------------------------------------------------- Sound+Decayed+Filled+Missing teeth

DENTAL HEALTH INDEX

It is a ratio of sound teeth minus unsound teeth, divided by the total number of teeth examined

DHI score ranges from -1 to +1

In 1981 the World Health Assembly of the WHO declared that the global goal for oral health by the year 2000 should be that the DMFT for the 12-year-olds should not exceed 3, in all the countries.

A new index called the 'Significant Caries Index' (SiC) was proposed in the year 2000),in order to bring attention to those individuals with the highest caries scores in each population.

The SiC Index is the Mean DMFT of the one third of the study group with the highest caries score. The index is used as a complement to the mean DMFT value.

SIGNIFICANT CARIES INDEX

To calculate Significant Caries Index:• Sort the individuals according to their DMFT• Select the one third of the population with the

highest caries values• Calculate the Mean DMFT for this subgroup.

Given by Ralph V Ratz in 1979

Root caries is defined as ‘a soft,irregularly shaped,progressive destructive lesion either totally confined to the root surface or involving the undermining of enamel at the cemento-enamel junction,but clinically indicating that the lesion initiated on the root surface’

ROOT CARIES INDEX (RCI)

Diagnosis:Lesions exhibiting gross cavitationA darkened,discoloured appearanceA tracky or leathery feel upon probing with

moderate pressureInstruments used: mouth mirror & dental

explorerMeasures the severity of the disease &

delineates the true intra-oral population at risk

Based on the requirement that gingival recession must occur before root surface lesion begins.therefore,only teeth with gingival recession are examined

Procedure:each of the four surfaces,the mesial,distal,buccal(labial) & lingual of a root are examined for a single tooth

For teeth with multiple root & extreme recession, the most severely affected root surface be recorded for that tooth

Missing-MNo gingival recession-NoRRecession present,surface decayed-(R-D)Recession present,surface filled-(R-F)Recession present,surface normal-(R-N)

M D B L

R-N

R-F

R-D

NoR

R-D + R-F------------------------ X 100 = RCI Score R-D + R-F + R-N

Diagnostic conventions proposed for RCI:

Convention 1:if diagnosis of caries or filled is uncertain,score the surface as ‘sound’

Convention 2:all caries detected on the root surfaces near CEJ shall be scored as ‘decayed’ regardless of the adjacent enamel condition

Convention 3:any coronal filling extending onto the root surface must extend 3 mm,beyond CEJ in order to score that root surface as ‘filled’

Convention 4:to score a filling as involving multiple surfaces, the filling must extend across atleast 1/3rd of each additional surface

Convention 5a:recurrent decay associated with root surface filling should be recorded as independent disease category called ’recurrent root decay’

Convention 5b:recurrent decay associated with coronal filling should be recorded as independent disease category called ’root decay contiguous with coronal filling’

Convention 6:for any root surface that is decayed,the events of an additional but separate root lesion is recorded as an independent disease category called’additional root caries lesion’

Convention 7:any root surface which appears sound but has more than 20% of its area in accessible to clinical examination due to calculus/heavy plaque deposits shall be scored as unreadable

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