Indices In Dental Epidemiology
Question 1. Define index. Classify them. State the ideal requirements of index and their use in epidemiological studies.
Or
Define index. What are the ideal requirements of an index in detail?
Or
Write short note on ideal requisites for dental index.
Or
What are the ideal requisites of epidemiologic indices.
Or
Write short note on ideal requisites of index.
Answer.
Definition of an Index
An index has been defined as a numerical value describing the relative status of a population on a graduated scale with definite upper and lower limits which is designated to permit and facilitate comparison with other populations classified by the same criteria and methods. —(Russell AL in 1969)
Classification of an Index
- Based upon the direction in which their score can fluctuate:
- Irreversible index:
- Index that measures the conditions that will not change.
- Irreversible index score cannot decrease in value on subsequent examination, e.g. an index that measures DMFT, DMFS index.
- Reversible index:
- Index that measures conditions that can be changed.
- Reversible index score can increase or decrease on subsequent examination, e.g. indices that measure gingival conditions, e.g. Loe & Sillness gingival index
- Composite index:
- It measures both reversible and irreversible conditions, e.g. Russell’s periodontal index.
- Irreversible index:
- Depending upon extend to which area of mouth or oral cavity measures:
- Full mouth index
- Theses indices measure the patient’s entire dentition or periodontium, e.g. Russell’s periodontal index.
- Simplified indices
- These indices measure only a representative sample of the dental apparatus, e.g. oral hygiene index- simplified (OHI-S).
- Full mouth index
Read And Learn More: Public Health Dentistry Question And Answers
- Indices may be classified in certain general categories according to entity which they measures like:
- Disease index: DME, D decayed portion
- Symptom index: Gingival bleeding index
- Treatment index: DMF index, F-filled portion.
- Dental indices can also be classified under special categories as:
- Simple index
- Index that measures the presence or absence of a condition, e.g. an index that measure the presence of dental plaque, e.g. Sillness & Loe plaque index
- Cumulative index
- Index that measures all the evidence of a condition, past or present, e.g. DMFT index for dental caries.
- Simple index
Ideal Requirements of an Index
Ideally an index should possess the following properties:
Clarity, Simplicity and Objectivity
The examiner should be able to carry the rules of the index in his mind, and the index should be reasonably easy to apply needing no expensive equipment. The index should be objective and unambiguous with mutually exclusive categories, e.g. Angle’s classification has strict criteria on the special relationship between the teeth.
Validity
The index must measure what it is intended to measure, it should correspond with clinical stages of disease under study at each point, e.g. The number of bacteria in a sample of saliva is not a valid measure of bacteria in dental plaque.
Reliability
Index should measure at different time and under a variety of conditions. In this there is determination of ability of same or different examiners to interpret and use index in same way.
Quantifiability
The index should be amenable to statistical analysis, so that the status of group can be expressed by a number that correspond to a relative position on a scale from zero to upper limit.
Sensitivity
Index should be able to detect reasonably small shifts, in either direction in group condition.
Acceptability
Use of index should not be painful to or demeaning to the subject.
Use of Index in Epidemiological Studies
- Index shows the prevalence and trends of incidence of a particular condition occurring within a given population.
- It provides baseline data for showing existing dental healthconditions in community.
- It measures effectiveness of specific agents used for prevention, control and treatment of oral conditions.
- It measures the prevalence and incidence of oral condition occurring within a population.
Question 2. Write notes on classification and criteria for selection of indices in epidemiology.
Answer.
Criteria for Selection of Indices in Epidemiology
- Following are the criteria for selecting the index, i.e.
- Index should be simple to use and calculate.
- Index should permit the examination of multiple people in a short time.
- Index should require minimum armamentarium and expenditure.
- Criteria of index should define its components clear and readily understandable for promoting maximum intra- and interexaminer reproducibility and standardization.
- Index should be free as possible from subjective interpretation.
- Index should define clinical conditions objectively.
- Index should be highly reproducible for assessing clinical condition when used by one or more examiners.
- Index should be amenable to statistical analysis.
- Index should be strongly related numerically to clinical stages of specific disease under investigation.
- Index is equally sensitive throughout the scale, if it is related to severity of variable.
- Index will not lead to discomfort to the patient and is acceptable to the patient.
Question 3. Name the different indices used in dentistry.
Answer. Following are the different indices used in the dentistry:
Various Indices Used in Dentistry
- Indices used in assessment of oral hygiene
- Oral hygiene index.
- Simplified oral hygiene index.
- Modified patient hygiene performance index.
- Plaque-free score index.
- Plaque control record.
- Oral health status index.
- Indices used in assessing plaque and debris
- Plaque component of the periodontal disease index.
- Schick and Ash modification of plaque criteria.
- Turseky Gilmore-Glickman modification of the Quigley Hein plaque index.
- Plaque index.
- Modified navy plaque index.
- Distal mesial plaque index.
- Indices used in assessing calculus
- Calculus surface index
- Calculus surface severity index
- Marginal line calculus index
- Calculus component of the periodontal disease index.
- Probe method of calculus assessment.
- Indices used in assessing gingival inflammation
- Papillary marginal attachment index.
- Gingivitis component of the periodontal disease index.
- Gingival index.
- Papillary marginal gingivitis index.
- Modified gingival index.
- Gingival tissue index.
- Gingival pain index.
- Indices used in assessing gingival bleeding
- Sulcus bleeding index.
- Papillary bleeding index.
- Gingival bleeding index.
- Interdental bleeding index.
- Gingival status index.
- Bleeding points index.
- Quantitative gingival bleeding index.
- Gingival fluid flow index.
- Indices used in assessing periodontal diseases
- Periodontal index.
- CPITN.
- CPI.
- Periodontal disease index.
- Gingival bone count index.
- Navy periodontal disease index.
- Gingivitis periodontitis missing teeth index.
- Periodontitis severity index.
- Extent and severity index.
- Gingival sulcus measurement component of periodontal disease index.
- Periodontal screening and recording index.
- Indices used in assessing dental caries
- DMFT index.
- DMFS index.
- Def index.
- Root caries index.
- Modified DMFT index.
- Caries severity index.
- Czechoslovakia caries index.
- DMF surface percentage index.
- Functional measure index.
- Dental health index.
- WHO dentition status.
- Restorative index.
- Indices used in assessing dental fluorosis
- Dean’s fluorosis index.
- Moller’s fluorosis index.
- Chronological fluorosis assessment index.
- Fluorosis risk index.
- Young’s classification.
- Al-alomsi classification.
- Murray and Shaw classification.
- The FDI index.
- Thylstrup Fejerskov fluorosis index.
- Tooth surface index of fluorosis.
- Indices used in assessing malocclusion
- Malalignment index.
- Handicapping malocclusion assessment index.
- Occlusal feature index.
- Occlusal index.
- Index of orthodontic treatment needs.
- Norwegian index of orthodontic treatment needs.
- Handicapping labiolingual deviation index.
- Master and Frankel index.
- Peer assessment rating index.
Question 4. Define an index. Enumerate qualities of an index. Describe oral hygiene index in detail.
Or
Write short note on oral hygiene index.
Answer.
Enumeration of Qualities of an Index
- Clarity, simplicity and objectivity
- Validity
- Reliability
- Quantifiability
- Sensitivity
- Acceptability
Oral Hygiene Index
- Oral hygiene index was developed by John C Greene and Jack R Vermillion in 1960.
- It has two parts, i.e. the debris index and the calculus index, and is an indication of oral cleanliness.
- The scores may be used singly or in combination.
- For scoring, the dentition should be divided into sextants and selects the facial or buccal and lingual tooth surface in each sextant that is covered with the greatest amount of debris and calculus. Twelve surfaces are evaluated.
- For this index, a surface includes half the circumference of the tooth.
- The maxillary and the mandibular arches are each composed of three segments.
Segments
Maxillary
- Segment 1: The segment distal to the right cuspid.
- Segment 2: Upper right canine to upper left canine.
- Segment 3: The segment distal to the left cuspid.
Mandibular
- Segment 4: The segment distal to the left cuspid.
- Segment 5: Lower left canine to lower right canine.
- Segment 6: The segment distal to right cuspid.
Each Segment is Examined for Debris or Calculus.
- From each segment one tooth is used for calculating the individual index, for that particular segment. The tooth used for the calculation must have the greatest area covered by either debris or calculus.
- The method for scoring calculus is the same as that applied to debris, but additional provisions are made for recording subgingival deposits.
Criteria and Scoring of OHI
Debris Score
Calculus Score
Calculations
- Buccal/labial and lingual scores should be totaled for each segment and arch.
- Debris as well as calculus scores should be calculated independently.
Debris Index (DI) = \(\frac{\text { Buccal total score + Lingual total score }}{\text { Number of segments scored }}\)
Calculus Index (CI) = \(\frac{\text { Buccal total score + Lingual total score }}{\text { Number of segments scored }}\)
For calculation of oral hygiene index debris and calculus index are summed, i.e.
Oral hygiene index = Debris index + Calculus index
Values of DI and CI ranges from 0 to 6 and value of OHI ranges from 0 to 12.
Interpretation
- Minimum points for all segments in either debris or calculus score is 0.
- Maximum points for all segments in either debris or calculus score is 36.
- Range of values from OHI is 0–12.
- High is the score, poor is the oral hygiene.
Question 5. Define an index. What are the ideal requirements of an index. Describe in detail OHI-S.
Or
Define an index. What are the ideal requirements of an index. Write in detail OHI-S.
Or
Write short note on OHI-S.
Or
Write short note on OHI-S by Green and Vermillion.
Answer.
Definition on Epidemiologic Index
“Epidemiologic indices are attempts to quantitate clinical conditions on a graduated scale, thereby facilitating comparison among populations examine by the same criteria and methods”. —Irving Glickman
Definition of an Index
An index has been defined as a numerical value describing the relative status of a population on a graduated scale with definite upper and lower limits which is designated to permit and facilitate comparison with other populations classified by same criteria and methods. —(Russell AL in 1969)
Oral Hygiene Index- Simplified (OHI-S)
- The simplified oral hygiene index (OHI-S) was developed in 1964 by John C. Green and Jack R Vermillion.
- Original oral hygiene index was determined to be simple, sensitive and useful, but it was time consuming and required more decision-making, so OHI-S was developed.
Selection of Tooth Surface
- The 6 surfaces are examined for OHI-S is selected from 4 posteriors and 4 anterior teeth.
- Surfaces and teeth to be examined.
- Only fully erupted permanent teeth are scored.
Exclusion
- Natural teeth with full crown restoration.
- Surfaces of teeth reduced in height by caries or trauma
Instruments Used
- Mouth mirror
- No. 23 explorer
Examination Method
- Surface area which is covered by the debris should be estimated by moving the side of explorer along the tooth surface which has to be examined.
- Extent of the debris is noted at incisal or occlusal surfaces till the area it is removed.
Scoring System
The OHI-S has two components the simplified debris index (DI-S) and the simplified calculus index (CI-S).
Scoring for Debris Index-Simplified
After the recording of six possible debris scores the teeth should be examined for calculus.
Scoring for Calculus Index-Simplified
Calculations
For every individual debris and calculus scores are totaled and divided by number of scored tooth surfaces.
Debris Index-Simplified (DI-S) = [/latex]\frac{\text { Total score }}{\text { Number of surfaces scored }}[/latex]
Calculus Index-Simplified (CI-S) = [/latex]\frac{\text { Total score }}{\text { Number of surfaces scored }}[/latex]
For calculation of oral hygiene index-simplified debris and calculus index-simplified are summed, i.e.
Oral hygiene index-simplified = Debris index-simplified + Calculus index-simplified
Interpretation
For DI-S and CI-S
Good – 0.0–0.6
Fair – 0.7–1.8
Poor – 1.9–3.0
For OHI-S score
Good – 0.0–1.2
Fair – 1.3–3.0
Poor – 3.1–6.0
Uses of OHI-S
- Widely used in studies on epidemiology of periodontal disease.
- In evaluation of public health program in community.
- For evaluating cleaning efficiency of toothbrush.
- For evaluating an individual’s level of oral hygiene.
Question 6. Write briefly on plaque index.
Or
Classify and write ideal requistes of index. Describe plaque index in details.
Answer.
- Plaque index was developed by Silness J and Loe H in 1964.
- Plaque index assesses thickness of plaque at cervicalmargin of tooth.
- Areas examined are distal, facial or buccal, mesial and lingual.
- The six index teeth used for examination are 16 12 24 36 32 44.
- If any of the index teeth is missing there is no substitution and full mouth examination has to be done.
Instruments Used
- Mouth mirror
- Dental explorer
- Air drying of teeth and gingiva.
Plaque Index Procedure
- Tooth should be air dried and are examined visually.
- When plaque is not visible explorer is used for testingthe surface.
- Explorer is passed across the tooth surface in cervical third and near the entrance to the gingival sulcus.
- When no plaque adhere to the point of explorer the area is considered to have 0 score.
- When plaque adheres, a score of 1 is assigned.
- Plaque which is on the surface of calculus deposits and on the dental restorations of all types in cervical third is evaluated and included.
Scoring
Calculation
- Plaque index score for the area: Each of the area, i.e. distofacial, facial, mesiofacial and lingual should assigned a score from 0 to 3.
- Plaque index score for the tooth: Score from four areas of tooth are added and divided by 4.
- Plaque index score for the individual: Indices for each of the tooth are added and then divided by total number of teeth examined. Its score ranges from 0 to 3.
- Plaque index score for a group: Indices for each member of a group or population is added up and then divided by total number of individuals in the group or population.
Interpretation
Uses
- Evaluates mechanical anti-plaque procedures as well as chemical agents.
- Can be used in large scale epidemiological studies.
Question 7. Write in brief on Turesky-Gilmore Glickmen modification of the Quigley Hein Plaque index.
Answer. Quigley and Hein were reported a plaque measurement that focused on the gingival third of the tooth surface, they examined only the facial surfaces of the anterior teeth.
- The Quigley and Hein Plaque index was modified by Turesky, Gilmore and Glickman reliable index for measuring plaque using an estimate of the tooth covered by plaque.
- This index emphasizes the difference in plaque accumulation in the gingival third of the tooth.
Method
Plaque is assessed on the labial, buccal and lingual surfaces of all the teeth after using a disclosing agent.
Scoring Criteria
This index is based on numerical scale of 0–5.
Plaque Scoring System by Quigley and Hein
Modified Plaque Scoring System by Turesky et al
Calculation
Index score = \(\frac{\text { Total score }}{\text { The number of surface examined }}\)
Interpretation
Score of 0 or 1 is considered as low.
Score of 2 or more is considered high.
Use
It is a comprehensive method for evaluating antiplaque procedures, such as toothbrushing and flossing as well as chemical antiplaque agents.
Question 8. Write short note on reversible index.
Answer. Reversible index measures conditions that can increase or decrease on subsequent examinations, e.g. Loe & Silness gingival index.
Loe & Silness in 1963 for purpose of assessing severity of gingivitis and its location in four possible areas by examining only qualitative changes of gingival soft tissue.
Instruments Used
- Mouth mirror.
- Periodontal probe.
Method
Severity of gingivitis is scored on all teeth or on selected index teeth.
Index teeth are:
- 16-Maxillary right first molar.
- 12-Maxillary left lateral incisor.
- 24-Maxillary left first premolar.
- 36-Mandibular left first molar.
- 32-Mandibular left lateral incisor.
- 44-Mandibular right first premolar.
Tissues surrounding each tooth are divided in 4 gingival scoring units: distofacial papilla, facial margin, mesiofacial papilla and entire lingual gingival margin.
Scoring Criteria
Calculations
- Gingival index (GI) score for area: Each area is assigned a score from 0 to 3.
- GI score for a tooth: Score from four areas of tooth are added and then divided by 4.
- GI score for individual: Indices for each of the teeth are added and then divided by total number of teeth examined. Score ranges from 0 to 3.
- GI score for a group: Indices for each population and group is added and then divided by total number of individuals in the group or population.
Interpretation
Use
- For determination of prevalence and severity of gingivitis in epidemiological surveys.
- For assessing severity of gingivitis in individual dentition.
- In the controlled trial of preventive agents.
Question 9. Define an index. Define the ideal characteristic of an index. Give the scoring criteria of Russell’s periodontal index.
Or
What is an index? Classify it and give the details of Russell’s periodontal index.
Or
Classify index. What are the ideal requisites of index. Mention in detail about Russel’s periodontal index.
Answer.
Russell’s Periodontal Index
- Periodontal index was developed by Russell AL in 1956.
- Russell’s periodontal index was intended to estimate the deeper periodontal disease by measuring the presence or absence of gingivitis and its severity, pocket formation and masticating function.
- Russell’s periodontal index is a composite index because it records both the reversible changes (due to gingivitis) and more destructive and presumably irreversible changes (periodontal disease).
- Russell’s periodontal index is probably the most widely used periodontal index in epidemiological survey around the world.
Method
- All the teeth present are examined.
- All of the gingival tissue circumscribing each tooth is assessed for gingival inflammation and periodontal disease.
Instruments Used
- Plain probe
- Mouth mirror
Scoring Criteria
- The scale of values for the Russell’s periodontal index ranges from 0 to 8, with increasing prevalence and severity of disease.
- Russell chooses the scoring values 0, 1, 2, 4, 6, 8.
Calculation of the Index
PI score per person = \(\frac{\text { Sum of individual score }}{\text { Number of teeth present }}\)
Interpretation
Drawback
- Underestimate the true level of periodontal disease.
- Scoring criteria are not continuous.
- Overlapping of the score.
- Loss of epithelial attachment is not recorded.
- Treatment needs are not indicated.
Uses
- Used in epidemiological survey of periodontal disease.
- Used in national health survey.
- More useful when it is necessary to distinguish between
- population with mild, moderate and advanced chronic obstructive disease.
Russell’s Periodontal Index Advantages
- Easy and quick.
- Measure both reversible and irreversible aspect of periodontal disease.
Question 10. Define an index. Enumerate qualities of an index. Describe CPITN index in detail.
Or
Define the index. Classify indices used for dental epidemiological investigations. Describe CPITNindex in detail.
Or
Write short note on CPITN index.
Or
Write in brief on CPITN index.
Or
Write short note on CPITN.
Or
Write notes on community periodontal index of treatment needs.
Or
Write short answer on CPITN.
Answer.
CPITN Index
- Community periodontal index of treatment need was developed for Joint Working Committee of the WHO and FDI in 1982.
- This index assess the periodontal treatment need andinclude:
- Presence or absence of gingival bleeding.
- Supra or subgingival calculus.
- Periodontal pocket.
Procedure for the CPITN
- The dentition is divided into six part (sextants).
- Each sextant is given a score.
- The score is identified by examination of specified index teeth.
Sextants
\(\begin{array}{l|l|l}17-14 & 13-23 & 24-27 \\
\hline 47-44 & 43-33 & 34-37
\end{array}\)
Index Teeth
- In epidemiological survey for adults aged 20 years or more, only 10 teeth known as index teeth are examined.
- The ten specialized index teeth are:
17 & 16 & 11 & 26 & 27 \\
\hline 47 & 46 & 31 & 36 & 37
\end{array}\)
- Molars are examined in pair and only one score, the highest is recorded.
- Only one score is recorded for each sextant.
- For young people up to 19 years, only six index teeth are examined.
- The six index teeth are:
16 & 11 & 26 \\
\hline 46 & 31 & 36
\end{array}\)
CPITN Probe
- It is the WHO periodontal examination probe.
- The recommended periodontal probe used with CPITN was described by WHO.
- This probe was designed for two purposes:
- Measurement of periodontal depth.
- Detection of subgingival calculus.
- CPITN probe is both thin in handle and is of very light weight (5 g).
- Pocket depth is measuring through color coating with as black mark starting at 3.5 mm and ending at 5.5 mm.
- The probe has a ball tip of 0.5 mm in diameter.
- That allows easy and nontraumatic detection of subgingival calculus.
- The probe has two additional lines at 8.5 mm and 11.5 mm from the working tip.
- The additional line use for recording deep pocket.
- According to WHO and FDI, the CPITN probe identified as either ‘CPITN-E’ (epidemiological probe) for the probe 3.5 and 5.5 mm marking or ‘CPITN-C’ (clinical probe) for the clinical probe with additional 8.5 and 11.5 mm marking.
Codes and Criteria
Appropriate code for each sextant is determined with respect to the following criteria.
Codes are as follows.
Treatment Need
Question 11. Write short note on CPI probe.
Or
Write short answer on CPITN probe.
Or
Write short note on CPITN probe.
Answer. It is also known as WHO periodontal examination probe.
- The recommended periodontal probe used with CPITN was described by WHO.
- This probe was designed for two purposes:
- Measurement of periodontal depth.
- Detection of subgingival calculus.
- CPITN probe is both thin in handle and is of very light weight (5 g).
- The pocket depth is measuring through color coding with as black mark starting at 3.5 mm and ending at 5.5 mm.
- The probe has a ball tip of 0.5 mm in diameter.
- This allows easy and non-traumatic detection of subgingival calculus.
- The probe has two additional lines at 8.5 mm and 11.5 mm from the working tip.
- The additional line is used for recording deep pocket.
- According to WHO and FDI, the CPITN probe identified as either ‘CPITN-E’ (epidemiological probe) for the probe 3.5 and 5.5 mm marking or ‘CPITN-C’ (clinical probe) for the clinical probe with additional 8.5 and 11.5 mm marking.
Question 12. Write briefly on CPI index.
Answer. Full form of CPI is community periodontal index.
CPI is the modification of CPITN index.
Three indicators of periodontal status are used for thisassessment:
- Gingival bleeding.
- Calculus.
- Periodontal pockets.
Instrument Used
- Mouth mirror.
- CPI probe.
Examination Probe
A specially designed lightweight CPI probe with a 0.5 mm ball tip is used, with a black band between 3.5 and 5.5 mm and rings at 8.5 and 11.5 mm from the ball tip.
Sextants
The mouth is divided into sextants defined by tooth numbers
18–14
13–23
24–28
38–34
33–43
44–48.
A sextant should be examined only if there are two or more teeth present and not indicated for extraction.
Selection of Teeth
For adults aged 20 years and over, the teeth to be examined are 17, 16, 11, 26, 27, 47, 46, 31, 36, 37.
Two molars in each posterior sextant are paired for recording, and if one is missing, there is no replacement. If no index teeth or tooth is present in a sextant qualifying for examination, all the remaining teeth in that sextant are examined and the highest score is recorded as the score for the sextant. In this case, distal surfaces of third molars should not be scored.
For subjects under the age of 20 years, only six teeth—16, 11, 26, 36, 31 and 46—are examined. This modification is made in order to avoid scoring the deepened sulci associated with eruption as periodontal pockets. For the same reason, when examining children under the age of 15 are examined, pockets should not be recorded, i.e. only bleeding and calculus should be considered.
Sensing Gingival Pockets and Calculus
An index tooth should be probed, using the probe as a “sensing” instrument to determine pocket depth and to detect subgingival calculus and bleeding response. The sensing force used should not more than 20 grams. A practical test for establishing this force is to place the probe point under the thumb nail and press until blanching occurs. For sensing subgingival calculus, the lightest possible force that will allow movement of the probe ball tip along the tooth surface should be used. When the probe is inserted, the ball tip should follow the anatomical configuration of the surface of the tooth root. If the patient feels pain during probing, this is an indicative of the use of too much force. The probe tip should be inserted gently into the gingival sulcus or pocket and the total extent of the sulcus or pocket explored.
Scoring Criteria
Codes and criteria for CPI are:
The index teeth, all remaining teeth in a sextant where there is no index tooth, should be probed and the highest score is recorded in the appropriate box. The codes are:
Codes for Scoring of CPI Index
Loss of Attachment
Information on loss of attachment gives an estimate of the lifetime accumulated destruction of the periodontal attachment, Loss of attachment should not be recorded for children under the age of 15.
Highest score recorded in the appropriate box.
Loss of Attachment Codes
Question 13. Define indices. Classify indices, write in detail on indices used in periodontal disease.
Or
Write short note on indices for recording periodontal disease.
Or
Define index. Describe in detail any two indices used for recording periodontal disease.
Answer.
Indices Used for Periodontal Disease
- Russell’s periodontal index.
- CPITN index.
- CPI index
- Periodontal disease index.
- Gingival bone count index.
- Navy periodontal disease index.
- Gingivitis periodontitis missing teeth index.
- Periodontitis severity index.
- Extent and severity index.
- Gingival sulcus measurement component of periodontal disease index.
- Periodontal screening and recording index.
Question 14. Define an index. Describe in detail about various indices used for management of dental caries.
Or
Write in brief on DMFT index.
Answer.
Indices for Management of Dental Caries
- DMFT index.
- DMFS index.
- def index.
- Root caries index.
- Modified DMFT index.
- Caries severity index.
- Czechoslovakia caries index.
- DMF surface percentage index.
- Functional measure index.
- Dental health index.
- WHO dentition status.
- Restorative index.
DMFT Index
DMFT index was developed by Henery T Klein, Carrole E Palmer and Knutson JW in year 1938.
Instruments Used
- Mouth mirror.
- Explorer.
Selection of Teeth
All the 28 teeth are examined.
Teeth which are not included are:
- Third molars
- Unerupted teeth
- Supernumerary and congenitally missing teeth
- Teeth removed for reasons other than dental caries, e.g for orthodontic purpose and impaction
- Teeth restored for reasons other than dental caries, such as trauma, use as a bridge abutment and cosmetic purposes.
- Retained primary tooth when the successor permanent tooth is present. Permanent tooth should be considered.
Procedure
Each tooth is examined by mouth mirror and explorer under adequate light. Teeth should be examined by visual means and only the small lesions should be checked by using dental explorer.
Rules for Scoring DMFT
- No tooth should be counted more than once.
- Decayed (D), missing (M) and filled (F) teeth should be recorded separately.
- Tooth lost or filled due to reasons other than caries are not included.
- Deciduous teeth are not considered in DMFT index.
- A tooth with several filling is counted as one tooth.
Criteria for Recording
- Decayed (D)
- When dental caries and a restoration are present on the same tooth, the tooth is recorded as D.
- When a crown is broken due to caries it is recorded as D.
- Tooth with temporary restoration are recorded as decayed.
- Missing (M)
- When a tooth has been extracted because of dental caries.
- When a tooth is carious, cannot be restored and is indicated for extraction.
- Filled (F)
- Permanent restorations are recorded as F.
Criteria for identification of Dental Caries
- Lesion is clinically visible and obvious.
- Discoloration or loss of translucency typical of undermined or demineralized enamel.
- Definite catch and the explorer tip can penetrate into soft yielding material.
DMFT Scores
Sum of the three figures for the DMFT value, e.g. DMFT of 3 + 4 + 9 = 16 means that 3 teeth are decayed, 4 teeth are missing and 9 teeth are filled. It also suggests that 12 teeth are intact.
Individual DMFT
- Total each component separately, i.e. total D, total M, total F
- Total D + M + F = DMF score.
Group average
Total DMF for each individual.
Divide total DMF by the number of individuals examined.
Average DMF = \(\frac{\text { Total DMF }}{\text { Total number of individuals examined }}\)
Treatment need
Percentage needing restorations (%) = \(\frac{\text { Total numbe of D tooth x 100 }}{\text { Total number examined }}\)
DMFS index
It assesses the total number of tooth surfaces affected. In this DMF is calculated per tooth surface.
Rules, methods and criteria are same as DMFT index except that all tooth surfaces are examined in DMFS index.
Surfaces Examined
Anterior teeth: Four surfaces are examined, i.e. facial, lingual, mesial and distal
Posterior teeth: Five surfaces are examined, i.e. facial, lingual, mesial, distal and occlusal.
Maximum value for DMFS is 128 for 28 teeth.
Posterior teeth: 16 with 5 surfaces: 16 × 5 = 80.
Anterior teeth: 12 with 4 surfaces: 12 × 4 = 48.
Total = 128 surfaces.
Calculations
Total number of decayed surfaces = D.
Total number of missed surfaces = M.
Total number of filled surfaces = F.
Total DMFS score for an individual = D + M + F (surfaces).
Dental Caries Index for Deciduous Teeth
This index was given by Grubbel in 1944. Since the index describe deciduous teeth it consists of 20 teeth.
It is represented as deft or defs.
d = Decayed primary teeth.
e = Extracted teeth/indicated for extraction.
f = Filled teeth/surfaces.
Selection of Teeth
All 20 teeth are selected.
For surfaces.
dmfs: 88 surfaces are evaluated.
Posterior teeth: 8 teeth with 5 surfaces: 8 × 5 = 40.
Anterior teeth: 12 teeth with 4 surfaces: 12 × 4 = 48.
Total = 88 surfaces.
Teeth Excluded
- Missing teeth, including unerupted and congenitally missing tooth.
- Teeth restored for reasons other than dental caries are not counted as f.
- Supernumerary teeth.
Procedure and Criteria
Same as DMFT.
Calculation
Total def score = d + e + f.
Total defs score = d + e + f surfaces.
Question 15. Write short note on DMF index.
Answer.
Modification of DMF Index (WHO Modification)
- All third molars are included.
- Temporary restorations are considered as ‘D’.
- Only carious cavities are considered as ‘D’.
- The initial lesions (chalky white spots, stains, fissures, etc.) are not considered a ‘D’.
- The DMF index can be applied to denote the number of affected teeth (DMFT) or to measure the surface affected by dental caries (DMFS).
Drawback of DMF Index
- DMFT value is not related to the number of teeth at rise of caries.
- DMFT index cannot be valid in older adults because teeth can become lost for reason other then caries.
- DMFT index can be misleading in children whose teeth have been lost due to orthodontic reasons or physiological exfoliation.
- DMFT index is of little use in studies of root caries.
- Even extreme clinical condition score cannot changed.
Question 16. Write short note on Moller’s Index.
Answer. This index system was developed by Moller IJ and Poulsen S in 1966, as a standardized system for diagnosis, recording and analyzing dental caries data.
Diagnostic Criteria
The criteria are specified for:
- Pit and fissure surface.
- Smooth surface.
- Radiographical evaluation of proximal surface.
Question 17. Write short note on Dean’s fluorosis index.
Answer. An index for assessment of dental fluorosis was introduced by Trendley H Dean in 1934 known as ‘Dean’s classification system for dental fluorosis’ or ‘Dean’s fluorosis index’
- The criteria form Dean’ fluorosis index or classification system, created by H T Dean in 1934 was based on a 7 point ordinal scale: normal, questionable, very mild, mild, moderate, moderately severe and severe.
- Dean introduced the revised version of his fluorosis index or fluorosis classification system in 1942, where he used a six point scale, i.e. Normal, questionable, very mild, mild, moderate and severe.
Dean’s Fluorosis Index—modified Criteria (1942)
Question 18. Write short answer on significant caries index.
Answer. Significant caries index was proposed in year 2000 by Bratthall D.
Purpose
As detailed analysis of caries condition was carried out in many countries in the world, it was seen that a skewed distribution of caries prevalence i.e. proportion of 12 years old still had high or very high DMFT value even though proportion was caries free. So the mean DMFT value did not accurately reflect this skewed distribution which leads to incorrect conclusion that caries situation for the whole population was controlled but in reality several individuals have caries. So to bring attention to such individuals with high caries score in each population significant caries index was proposed.
Procedure
Significant caries index is mean DMFT of one third of study group with highest caries score. It is mainly used as compliment to mean DMFT value.
Calculation
- Individuals are sorted according to their DMFT
- Select one third of population with highest caries value
- Calculate mean DMFT for the subgroup
Step 1:
Original set of data should be presented s DMFT distribution
in a population or in a group.
Sum of DMFT values: 2+1+0+0+5+0+14+3+0+2+0=27
Total number of individuals is 11
Average of DMFT value is 27/11=2.45
So, mean DMFT is 2.5
Step 2:
Examine how many individuals are present in one third of the population. Value of one third in the example is 11/3=3.66
Rounded number of the subgroup 4
Numerically sort out the data and select four individuals of the population with highest DMFT values.
So, the selected DMFT values in the selected subgroup are 2,3,5,14.
Add each of the DMFT value in subgroup: 2+3+5+14 = 24.
Now divide the addition value by total number of individuals in subgroup 24/4 = 6.
Result
The significant caries index for this population group is 6.
A new oral health goal was proposed by WHO that, once the goal of 3 DMFT has attained, next step is to achieve significant caries index of less than 3 DMFT in 12 year old children, globally till 2015.
When a particular country reach this goal, proposed idea is to see provinces, district, cities or parts of districts/cities, so that in any of the population, significant caries index is lower than 3 DMFT value.
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