Definition And Classification of Indices
Your Ad Here

Definition And Classification of Indices

Indices

Community Dentistry

Definition

Russell defines index 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 comparison with other populations classified by the same criteria and methods”

 

CLASSIFICATION OF INDEX:

1. Based on the direction in which their scores can fluctuate:

  1. Irreversible index: Measures conditions that will not change scores once established cannot decreases in value on subsequent examination, e.g. Dental caries indices, Fluorosis index.
  2. Reversible index: Measures conditions that can be changed and scores can increases or decreased in subsequent examinations, e.g. periodontal indices.

2. Depending on extent to which areas of oral cavity are measures:

  1. Full mouth indices: measure the patient’s entire periodontium or dentition, e.g. Russell’s periodontal index.
  2. Simplified indices: Measure only a representative sample of the dental apparatus, e.g. OHI-S

 

3. According to the entity which they can measure:

  • Disease index
  • Symptom Index
  • Treatment Index
The D portion of the DMF index best exemplifies the disease index. The index measuring gingival or sulcular bleeding are essentially symptom indices. The F portion of the DMF index best exemplifies a treatment index.

 

In general there are 2 types of index:

  1. Measures the number or proportions of people in a population with or without a specific condition at a specific point in time or interval of time.

     2.  Measures the number of people affected and the severity of the specific condition at a specific time or interval of time.

 

Classified under special categories as:

  1. Simple index: Measures presence or absence of a condition, eg. An index that measures the presence of dental plaque without an evaluation of its effect on gingiva
  2. Cumulative index: Measures all the evidence of a condition , past and present , e.g. DMF index for dental caries.

 

Your Ad Here