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DENTAL CARIES INDICES Indices are a par of any epidemiological study. So now a question arises what’s epidemiology. This in brief can be defined as “a science that delas with the incidence distribution and control of the disease in population”. If dental epidemiologist is assigned to study about dental caries, its necessary that he should know the indices for caries, so that he can guage the extent and severity of dental caries and can compare his results with the others. So, the simple way the dental epidemiologist can measure is to count the number of cases of its occurrence and this count can be turned into a proportion by adding a denominator, thus determining prevalence. To improve dental public health in general, measurement of diseases in quantitative terms is very important. This quantitative measurements allows one to assess whether new methods of treatment are superior or inferior to existing modes, and whether prevention program are accomplishing or failing their objectives. Quantitative measurement of disease most commonly relies on ‘Indices”. Definition of Index Index – if used singularly, plural of this is Indexes or Indices.

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1. An Index is a graduated, numerical scale having upper and lower limits, with scores on the scale corresponding to specific criteria, which is designed to permit and facilitate comparision with other population classified by the same criteria and methods – By Russel A.L. 2. Epidemiological indices are attempts to quantitative clinical conditions on a graduated scale, thereby facilitating comparision among populations examined by the same criteria and methods – Irving Glickman. 3. Dental index is an abbreviated measurement of the amount of condition of disease in a population; a numerical scale with defined upper and lower limits designed to permit and facilitate criteria and methods – Pamela Zarowski. 4. An Index an expression of clinical observations in numerical values which is used to describe the status of the individual or group respect to condition being measured – Esther M. Wilkins. 5. Oral indices are essentially sets of values, usually numerical with maximum and minimum limits, used to describe variables or specific conditions on a graduated scale, which use the same criteria and method to compare a specific variable in individuals, samples or populations

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with that same variable as is found in other individuals, samples or population – George P. Barnes. Classification of Indices: A.

Classification based upon the direction in which their scores can fluctuate, Indices are classified as follows:

1.

Irreversible Index: Index that measure conditions that will not change. In this index score

once established cannot decrease in value or subsequent examinations. e.g. Index that measures dental caries. 2.

Reversible Index: Index that measures conditions that can be changed. Reversible index

scores can be changed i.e., can increase or decrease on subsequent examinations. e.g. Indices that measure periodontal conditions. B.

Indices can also be classified depending upon the extent to which the areas of oral cavity are measured.

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1.

Full Mouth Indices: These Indices measure the patients entire periodontal or dentition. e.g. Russell’s periodontal Index.

2.

Simplified Indices: These indices measure only representative samples of dental apparatus. e.g. Green and Vermillion’s simplified oral hygiene index. – OHI-S.

C.

Indices are also classified in general categories according to the entity which they measure:

1.

Disease Index: e.g. ‘D’ (Decay) portion of the DMF index is the best example for

disease Index. 2.

Symptom Index: e.g. Measuring gingival or sulcular bleeding are essentially examples

for symptom indices. 3.

Treatment Index: e.g. The ‘F’ (Filled) portion of DMF index is best example for

treatment index.

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D.

1.

In general indices are classified into: -

Simple Index

-

Cumulative Index

Simple Index: Index that measure the presence or absence of condition. e.g. In index that measure the presence of dental plaque without

evaluation of its effect on gingiva. 2.

Cumulative Index: Index that measures all the evidences of a condition, post and present. e.g. DMF index for dental caries.

3.

Indices used for Assessment of Dental Caries:

Definitions of Dental Caries: 1.

It is defined as a progressive irreversible microbial disease affecting 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.

2.

It’s a microbial disease of the calcified tissue of the teeth, characterized by demineralization of inorganic substances of the tooth. 5


3.

A carious lesion might be a disclosed spot, pit or tissue when probed will have a next with a soft floor. a.

The probe ‘catches’ in a pit or tissue but does not penetrate to the dentine. This is a category that, in clinical practice, a dentist might regard as suspect but not one that required immediate restorative treatment.

b.

There’s an obivious carious lesion involving dentine. In clinical term this tooth would be considered as needing a restoration.

c.

There is cavitation involving the pulp. The tooth would require extraction or endodontic treatment. Indices for dental caries have been formulated by many investigators.

The measurements of the intensity of dental caries, such as preparation of tooth last through caries, and percentage of teeth affected by caries have been in use since the early years of twentieth century. Properties of an ideal Index: 1. Clarity, simplicity and Objectivity: The index should be reasonably easy to apply so that there is no undue time lost during field examinations. The criteria of index should be clear and unambiguous, with mutually exclusive categories.

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2. Validity: The index must measure what it is intended to measure, so it should correspond with clinical stages of the disease under study at each point. 3. Reliability: The index should measure consistently at different times and under a variety of conditions. 4. Quantifiability: The index should be amenable to statistical analysis, so that a status of a group can be expressed by a number that corresponds to a relative position on a scale from zero to the upper limit. 5. Sensitivity: The index should be able to detect reasonably small shifts, in either direction, in the group condition. 6. Acceptibility: The use of index should not be painful or demeaning to the subject. Dental caries indices give information about: 1. The number of persons affected by dental caries. 2. The number of teeth that need treatment. 3. The number of surfaces involved. 4. The number of teeth that have been treated. 5. The number of teeth missing due to caries etc.

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And other statistical data useful in organizing and evaluating dental health programme efforts. Historical Background on Dental Caries Indices: Bodecker C.F. and Bodecker H.W.C. in 1931 described a caries index. This index. This was found to be sensitive but too complex for use in epidemiological surveys. Bodecker modified the caries index later, where in addition to counting the surfaces decayed an extra count was allotted from those surfaces that could experience multiple caries attacks. But this was also not used in major epidemiological studies. The approach to measuring caries by counting the number of teeth in the mouth visibly affected by caries was used in a systemic manner by Dean H.T and associates in their historic studies of dental caries with fluoride relation. In 1934 Mallanby M. described the carious lesions depending upon the degree of severity and numerically expressed it as follows: 1. Slightly caries 2. Moderate caries 3. Advanced caries

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DMF Index: This index was introduced in 1938 by Henry Klein, C.E. Palmer and J.W. Knutson. DMF Index is employed universally for measuring dental caries. This index is based on the fact that the dental hard tissues are not self limiting and self healing so established caries are scar of some sort. One tooth either remains decayed, or filled or it is extracted. The DMFT is an irreversible index, i.e., measures total lifetime caries experience. Method of DMF Recording: It’s applied only to permanent teeth. D – used to denote decayed tooth or teeth. M – used to denote missing teeth due to caries. F – used to denote permanently restored teeth earliest affected by caries. 28 permanent teeth are examined. The teeth which are not included to apply DMF index for recording are: a.

Third Molars.

b.

Unerrupted teeth.

c.

Congenitally missing and supernumery teeth.

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d.

Teeth removed for reason s other than dental caries, such as, for orthodontic purposes, for prosthodontic purposes and for esthetic purposes or impacted one.

e.

Teeth restored for reasons other than dental caries such as # teeth or repair of traumatized teeth or cosmetics purpose or for use as a bridge abutment.

f.

Primary tooth retained with the permanent successor erupted. The permanent tooth is evaluated, since a primary tooth is never included in this index.

The diagnostic tools which are used in procedure: a. Mouth mirror. b. Probe or explorer. Criteria for identification of dental caries a.

The lesion should be clinically visible and obvious.

b.

The explorer tip should penetrate deep into soft yielding material, undermined or demineraliased.

c.

The explorer tip in a pit or fissure get caught and resists removal after moderate to firm pressure on insertion.

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d.

There should be softness at the base of the area explored or examined.

Principles and Rules in Recording DMF: 1. No tooth should be counted more than once. It is either decayed, filled or missing or sound. 2. Decayed, missing and filled teeth should be recorded separately since the components of DMF are of great interest. 3. When counting the number of decayed teeth, also include teeth with permanent restoration showing signs of recurrent decay. 4.

Care must be taken in enlisting missing teeth giving the history of extractions due to caries. Badly decayed teeth indicated for extraction should also be included under missing one. (Too mobile a tooth due to periodontal disease also can be counted under missing category provided it has carious lesions).

The following teeth should’nt be counted as missing: a. Unerupted teeth. b. Teeth missing due to trauma or accident. c. Congenitally missing teeth/ d. Teeth which have been extracted for reasons other than caries.

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5. A tooth with multiple restorations should be counted as one. 6. Deciduous teeth are included in DMF count. 7. A tooth is considered to be erupted when the complete occlusal surface or incisal edge is totally exposed or can be exposed by gently reflecting any overlying gingival tissue with the mirror or explorer. 8. A tooth is considered to be present even though the crown has been destroyed and the roots are left. Limitations of DMF Index: 1.

DMF values are not related to number of teeth at risk: DMF scores are simple count. There is no denominator to an

individual’s DMF score. As a result, the DMF scores do not directly give an indications of the intensity of the attack in any one individual. 2.

The DMF index can be invalid in older patients or adults, because teeth can become lost for reasons other than caries: It has been suggested by the World Health Organization that the M

component of average DMF scores over age 30 might be more appropriately called the tooth mortality score. In other words after 30 years, the M

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component is not necessarily a valid reflection of tooth loss because of dental caries. 3.

The DMF index can be misleading in children whose teeth have been lost due to orthodontic reasons. In children the missing bicuspids is seen, the reason being orthodontic

treatment. Here the if the M component is included in the score, it may give misleading results. 4.

The DMF index can overestimate caries experience in teeth in which “preventive fillings� have been placed. Some dentists place restorations in teeth that although not yet carious

they think may decay in future. In an epidemiological survey, such teeth must be included in the F component of DMF, although had they not been filled in the first place. If such preventive fillings are included, the DMF Index gets inflated. 5.

The DMF index is of little use in studies of root caries. The lesion may begin below the ceneto-enamel junction and may not be

visible to be considered in the count. Other methods of measuring dental caries using different philosophical base from that of DMF index have been suggested.

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One is Grainger’s Hierarchical method. In ordinal scale designed to simplify the recording of the caries status of a population, which uses five zones of severity of the carious attack. This has not received wide acceptance. 6. Different criteria for organizing pit and fissure caries by “Anglo-saxon” system and the “European System”. Anglo-Saxon [Liberal] Described by Horowitz. Pits and fissures on the occlusal, vestibular, and lingual surfaces are carious when explorer “catches” after insertion with moderate to firm fissure and when the “catch” is accompanied by one or more of the following signs of decay. 1. Softness at the base of the area. 2. Opacity adjacent to the area provides evidence of undermining or demineralization. 3. Softened enamel adjacent to the area that may be scraped away by the explorer. European System (Conservative)

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In upper molars, mesio-occlusal and disto-occlusal palatine fissures assessed separately. In lower molars, the occlusal fissures and the buccal pits are assessed separately. Teeth are dried, sharp new explorers used, caries diagnosed in four categories. Described by Backer – Dirks, Houwink and Kwant. European System – Backer – Dirks, Houwink and Kwant. C I – Minute black line at base of fissure. C II – In addition, a white zone along margin of fissure (dark in transmitted light). C III – The smallest perceptible break in the continuity of the enamel. C IV – Large cavity, more than 3mm wide. Gradation for smooth surface and proximal surface caries. Grade 0 – Healthy. Grade 1 – Chalky spot less than 2mm in extent. Grade 2 – Chalky spot greater than 2mm. Grade 3 – Frank defect less than 2mm. Grade 4 – Frank defect greater than 2mm. 15


Definition and radiographic grade of lesion severity on proximal surfaces: Grade 1: Radiolucency also in the inner half of the enamel. No Initial lesion. Grade 2: Radiolucency also in the inner half of the enamel. No dentinal alterations. Grade 3: Radiolucency extending completely through the enamel, with evident radiolucency in the peripheral dentine. Grade 4: Obvious dentinal radiolucency even close to the pulp. When radiographically detectable radiolucencies exist in fissures, pits or on smooth surfaces, one is always dealing with clinical grade 4 carious defects i.e. with a large cavity. F (filled =5) If a filling with “secondary caries” is detected on a tooth surface, that surface is counted as a ‘D’ and not as an ‘F’. Alternatively a special category “D+F” may be employed. Gold crown or post crown. On molars: all 4 surfaces are counted. On Bicuspids: only 3 surfaces are counted. On Anterior teeth: all 4 surfaces are counted. “M” (missing =6)

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Here the same rules as those for crowned are applicable. Its better to dictate numbers rather than letters of the alphabet. 0: Healthy. 1, 2, 3, 4: These numbers signify decay (‘D’) and express the severity of the carious lesion i.e. (3=D3). 5: Means ‘F’ 6: Means M 7: Unerupted. DMFS: Here the ‘S’ component stands for surface. Maximum surfaces at risk are 128. Definition of caries intensity: Caries intensity is the percentage of DMFT or, better of DMFS entities within the teeth at risk (28) or surfaces at risk (128). The caries intensity can be expressed with or without consideration of initial lesions. The definition dmf indices: There are indices for the primary dentition. This in 1944 was described by Gruebbel. d – denote decayed deciduous teeth. f – filled deciduous teeth.

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m – teeth missing for any reason. e – decayed deciduous indicated for extension were not recorded. When this index is used in this manner the normal exfoliation of primary teeth is a complicating factor; naturally shed teeth should of course be included. Modifications are sometimes made to allow for this natural loss of teeth. When the index is used to measure post and present caries experience it has been suggested that is should be called dmf to avoid confusion with original deference of Gruebbel. The WHO recommendation of primary teeth is to use the same criteria as for permanent teeth except that missing teeth are disregarded after 9 years of age and only recorded as missing under this age if normal exfoliation would not be sufficient explanation for absence. DMFS and dmfs Indices: There DMFS and dmfs indices are calculated in the same way as that of DMF and dmf indices. It has been found that the surface index provides little or no additional information in prevalence studies. S & s – surface component. Disadvantages of DMF:

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A tooth scores exactly the same under extremes of clinical conditions, a tooth with a small restorations in one pit rates the same as tooth that has been extracted. Saturation of the index in older age groups, thus preventing the registration of further attack.

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Criteria for DMFT 1.

Scoring pattern and calculation – Range 0-28 or 0-32 Total no. of scores (for a person) No. of teeth examined

2.

Average DMF for a group: Total no. of affected teeth x 100 Total no. of individuals examined in group

DMFS Index When this index is used, decayed, missing, and filled surfaces are counted. Maximum possible score is 148 if 3 rd molars are included or 128 if 3 rd molars are excluded. Criteria for DMFS Index: Score 0 or 1 is given depending upon the condition. Calculation for DMFS score. 1. Average individual DMFS Total of score = No. of tooth surfaces

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2. Average DMFS is Total no. of individual DMFS = No. of teeth examined  % of population with the disease No. with caries P=

x 100 No. of people examined

Root Caries Index This index measures the attack rate of caries on exposed root surfaces. This index is one of the attempts to access the extent of root caries experience within the context of individual risk for the disease. “Katy” reasoned that only root surfaces that are exposed to the oral environment are at risk to develop root caries. Those root surface where gingival recession has not occurred cannot develop root caries and therefore should not be considered in assessing the attack rate of root caries. The RCI records these data as follows: (R-D) + (R-F)

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x 100 = RCI (R-D) + (R-F) + (RN) R-D – Root surface with decay. R-F – Root surface that is filled. R-N – Sound root surface. Stone’s Index In 1944, Stone, Lawton, Brambly and Hartley introduced an index for caries which came to be known as Stone’s Index. Scoring Criteria: 1. Caries detection by sharp probing where the lesion is not penetrating through the enamel to involve dentine. 2. Were on probing the lesion is uptill the denture i.e., less than quarter of the crown is destroyed. 3. Total destruction of more than quarter of the crown. Caries Indices for Mixed Dentition Both DMFT and deft. i.e., each child has to give separate index for permanent and deciduous teeth. The index for permanent teeth is usually determined first and then the index for deciduous separately.

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Caries Severity Index This index is given by Tank Certrude & Storvick Clara in 1970. This index helps to study the depth and extent of the caries surfaces and the extent of pulpal involvement. The 1952 Massler and Schous’s Index on progress of dental caries in stages is modified into caries severity index. This index is used to measure the extent and depth of decayed surfaces and pulpal involvement based on clinical and radiological examination. Scoring Criteria: 1 – Superficial caries (in enamel) 2 – Moderate caries (caries in enamel and superficial in dentinal) 3 – Moderately severe (enamel undermined) 4 – Severe (approaching pulp, enamel collapsed) 5 – Pulpitis (caused either by deep seated caries or by trauma without caries). 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).

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Czechoslovakian Caries Index: This index was introduced by Ponsova Novak and Matena in 1956. This is mainly used to compare caries experience in one group with that of the other groups with a similar population density but living in different environments. In this Index, the ‘variables’ seem to be controlled. In this Index, the average number of teeth or tooth surfaces and tooth areas and condition of previously extracted or crowned teeth were considered. The formula for this caries index (in adults) 1 – C – Fc – 4/5E – 2/3AT = Base Where, C = Caries Fc = Filling and crowns E = Extraction and AT= Anchorage teeth. This formula can be applied either for an individual or for collective index.

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In case of individual examination the ‘Base’ given by here is the amount of teeth in adult dentition (32). And in case of collective studies the ‘Base’ is the number of persons examined multiplied by 32 to establish the correct base figure. Average index value will be between 0 to 1. When caries index is 1, it shows higher caries frequency. Caries susceptibility index: It was developed by Richardson A. in 1961 for assessing caries susceptibility. This index is based on Bodecker and Meldanby caries index. There are two factors involved in measuring caries susceptible using the dynamic survey. They are: a) b)

Amount of tooth surface at risk. Amount of caries developing during the period of observation.

Here B) divided by a) will give a measure of susceptibility. Susceptibility surfaces for this index are: In case of incisors: 4 surfaces (Mesial, Distal, Buccal, Lingual)

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Canine: 4 surfaces (Mesial, Distal, Buccal, Lingual) Premolars: 5 surfaces (Mesial, Distal, Buccal, Lingual and Occlusal). Molar: 5 surfaces (Mesial, Distal, Buccal, Lingual and Occlusal). 148 susceptible surfaces for permanent dentition. 88 susceptible surfaces for deciduous dentition. Each individual is examined initially for tooth surfaces with caries and restored surfaces and are noted down. The individual is re-examined after a observation period of twelve months and six months. If new carious lesion have developed on any surface they are noted down. Previously restored surfaces are checked, if there is initiation of any secondary carious lesion, they too are noted down. From initial examination, the number of susceptible surfaces are calculated for each individual. Each tooth surface which is caries free and had not been restored is considered susceptible. The susceptible caries score is calculated. Second inspection (i.e., 6 month / 12 months after initial inspection). Susceptibility Ratio No. of caries surfaces developed during period of observation SR = No. of susceptible surfaces determined in the first inspection or initial examination.

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With the help of this above rates, we can calculate the susceptibility index (SI). i.e., SI = Susceptibility Ratios x 100 i.e., SI = SR x 100 This index is expressed as a percentage, since this mathematical results of the scoring will become more appreable (also fractions are raised to whole number). DMF Surface Percentage Index: It was developed by Jager C.L. in 1963. In this index the age of the subject is considered. Since different number of surfaces are present at different ages. The total surface value for each age group can be expressed as a percentage to find the age factor. Simplified age factors for different age groups are: For age: 6 – 7 ½ months

Age factor is 6

7 – 9 months

Age factor is 3

12 – 14 months

Age factor is 2

16 – 18 months

Age factor is 1.5

20 months – 5 years

Age factor is 1

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6 – 11 years

Age factor is 0.9

12 – 16 years

Age factor is 0.8

17 years

Age factor is 0.7

The calculation will be percentage of caries index. = Total of caries surface value (csu) x Age factors / individual age groups. Moller’s Index This index developed by Moller I.J. and Poulsen S. in 1966. It is one of the standardized system for diagnosing, recording and analyzing dental caries data. A standardized system for diagnosing, recording and analyzing dental caries data includes. 1. Standardization of diagnostic criteria. 2. Standardization of the equipment used for the examination, and 3. Standardization of the recording procedures and the field records. The scoring criteria specified for: i)

Pit and fissure surfaces

ii)

Smooth surfaces

iii)

Radiographic evaluation and proximal surfaces 28


‘0’ Pit & fissures caries Smooth surface caries Proximal surface caries Sound (Normal Sound (Normal) Enamel surface contrains distinct & unbroken. ‘1’ Discoloration definite sticking probe.

& White opaque area with Enamel surface contour of loss of luster, no loss of is broken a shallow substance. between the enamel surface and border not more than ¼ thru the enamel.

‘2’ Definite sticking of probe with or without discoloration. No dentine involvement.

This continuity of Shadow has reached enamel loss of dentino enamel junction. substance. No dentine involvement.

‘3’ Definite cavity with Dentine involvement dentine involvement.

‘4’ Probable complication.

pulp Probable complication.

A shadow between the dentine enamel junction and a border not more than half way thru the dentine.

pulp Shadow more than half way thru dentine.

Equipment used while recording -

Unscratched mouth mirrors.

-

Standardization dental probes (‘Holst’ probe).

All teeth are examined (excluding 3rd molars). A tooth is erupted when any part of it projects through gingiva.

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For molars and premolars – 5 surfaces. For canines and incisors – 4 surfaces. For primary dentition examination, the method is same as that for the permanent dentition. The coding criteria is: 0 – Sound tooth 1 – Type 1 caries 2 – Type 2 caries 3 – Type 3 caries 4 – Type 4 caries 5 – Filled tooth 6 – Missing tooth due to caries 7 – Tooth / tooth surface not erupted 8 – Tooth missing for reasons other than caries 9 – Congenitally missing and not recordable. Recently Developments on Caries Indices Oral health status index (OHSI) This index measure DMFt including 15 other variables, such as dysfunction, degree of periodontal disease and tumours.

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Functional measure Index: (FMI) It is a modification of DMFT index. In FMI the filled and the sound teeth are weighted equally, while the decayed and missing teeth are given zero weightage. This is calculated by adding the filled and sound teeth and then dividing by total number of teeth present i.e., 28 – Excluding 3rd molars. Filled + Sound

The score range from 0 to 1

FMI = 28 Tissue Health Index (THI): This also is a DMFt modification. In this index selecting weighting is given for decayed, filled and sound teeth. i.e.,

1 – decayed; 2 – Filled & 4 – Sound. Decayed + filled + sound teeth So THI = 28 1+2+4 =

7 =

28

8

Therefore score ranges between 0 and 1. 31


Dental Caries Severity Index for Primary: This is introduced by Aubrey Chosack in 1985. This index is based on the clinical examination only, which could be used in surveys of dental caries and give information in addition to ‘def’ figures especially when investigating preventive measures. Criteria for scoring: A.

Occlusal surfaces & pits & fissure caries on buccal and palatal surfaces of molars.

1 – Early pit & fissure caries where one slight catch is present on exploring with the explorer and resist while removing with moderate to firm pressure. 2 – Cavitation of atleast 1mm across the smallest diameter at the tooth surfaces. 3 – Cavitation measures breaking down or undermining of (discoloration) atleast half a cusp. B.

For buccal, lingual and palatal smooth caries.

1 – A white lesion not extending to the embrasure areas, found to be soft and sticky by penetration with the probe.

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2 – Cavitation of atleast 1mm but less than 2mm across the smallest diameter, or a soft sticky white lesion extending into one embrasure. 3 – Cavitation of atleast 2mm in the smallest diameter or a soft sticky white lesion extending into both embrasure. C.

For proximal surfaces of Molars.

1 – A discontinuity of the enamel in which an explorer will “catch” and there is softness. 2 – Cavitation with early breakdown of the marginal ridge or obvious discoloration indicating undermining of the ridge. 3 – Breakdown of the marginal ridge with cavitation extending to the mesial or distal extending of the occlusal fissures. D.

For proximal surfaces of incisors and canines

1 – A discontinuity of the enamel in which an explore will catch if there is softness. 2 – Cavitation with breakdown or obvious discoloration, indicating undermining for atleast 1mm on the labial or lingual surfaces. 3 – Cavitation with breakdown of the incisal edge or undermining of the edge as indicated by obvious discoloration.

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Here only largest caries involvement is scored for any one surface. Scores of 2 or 3 more lesions on one surface are not combined. Here a filled surface is given a score ‘1’. Secondary caries in major restoration is given score of ‘2’. The caries severity index (CSI) for the population in the mean of the scores for the carious teeth. Teeth free of caries are not included in this calculation.

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