Dental Indices

Definition of Dental Index

• A dental index is a numerical value that describes the relative status of a population on a graduated scale with definite upper and lower limits.
• It allows for comparison with other populations classified by the same criteria and methods.

Properties of Ideal Index

• Reliability: able to measure consistently at different times and under various conditions.
• Validity: accurately reflects the extent or degree of a condition or disease.
• Clarity, simplicity, and objectivity: easy to apply, with clear and simple criteria.
• Quantifiability: can be statistically analyzed.
• Acceptability: not painful or harmful to use.
• Sensitivity: detects reasonably small shifts.

Types of Indices

• Simple index: measures presence or absence of a condition (e.g., plaque index).
• Cumulative index: measures all evidence of a condition (e.g., DMFT index for dental caries).
• Irreversible index: measures conditions that will not change (e.g., dental caries index).
• Reversible index: measures conditions that can be changed or reversed (e.g., gingival index).
• Full mouth indices: measures the entire periodontium or dentition (e.g., Russell's periodontal index).
• Simplified indices: measures representative samples of dental apparatus (e.g., Green and Vermillion's simplified oral hygiene index (OHI-S)).

Classification of Indices

• Disease index: measures the presence of a disease (e.g., D portion of DMFT index).
• Symptom index: measures symptoms of a disease (e.g., gingival or bleeding index).
• Treatment index: measures treatment received for a disease (e.g., F portion of DMFT index).

Purpose and Use of Index

• Individual assessment: evaluates and monitors oral health, monitors healing process.
• Clinical trial: determines the effect of an agent or procedure on disease prevention, progression, or control.
• Community health and epidemiological survey: studies disease characteristics of a population.

Indices Used in Dentistry

• Oral hygiene indices:
  • Oral hygiene index
  • Simplified oral hygiene index
  • Modified patient hygiene performance index
  • Plaque free score index
  • Plaque control record
  • Oral health status index
• Periodontal disease indices:
  • Plaque component of periodontal disease index
  • Schick and Ash modification of plaque criteria
  • Periodontitis severity index
  • Extent and severity index
  • Gingival sulcus measurement component of periodontal disease index
  • Periodontal screening and recording index
• Caries indices:
  • 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
• Fluorosis indices:
  • Dean's fluorosis index
  • Moller's fluorosis index
  • Chronological fluorosis assessment index
  • Fluorosis risk index
  • Young's classification
  • Murray and Shaw classification
  • The FDI index
  • Thylstrup Fejeskov fluorosis index
  • Tooth surface index of fluorosis
• Malocclusion indices:
  • 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
  • Massler and Frankel index
  • Peer assessment rating index

Caries Index (DMFT)

• DMFT numerically expresses caries prevalence by calculating the number of teeth (T) that are:
  • Decayed (D)
  • Missing (M)
  • Filled (F)

Rules for Scoring DMFT

• No tooth should be counted more than once.
• Decayed, missing, and filled teeth should be recorded separately.
• Tooth lost or filled due to reasons other than caries are not included.
• Deciduous teeth are not considered in the DMFT index.
• A tooth with several fillings is counted as one tooth.

Criteria for Recording

• Decayed (D): when dental caries and a restoration are present on the same tooth, or when the crown is broken due to caries, or when a tooth has a temporary restoration.
• Missing (M): when a tooth has been extracted due to dental caries or when a tooth is carious and cannot be restored.
• Filled (F): when a permanent restoration is present.

Community Periodontal Index (CPI)

• Developed by WHO to assess periodontal treatment needs.
• Used to determine the need for periodontal treatment rather than determining past or present periodontal status.
• Indicators of periodontal status are used for assessment.
• A specially designed lightweight CPI probe with a 0.5mm ball tip is used.
• The probe has a black band between 3.5 and 5.5mm and rings at 8.5mm and 11.5mm from the ball tip.
• Measurement: 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, and 31.
• For subjects under the age of 20 years, only six teeth are examined: 16, 11, 26, 36, 31, and 46.
• Codes and criteria used in CPI: healthy periodontal tissue, no disease.