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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