Dental Indices are designed to measure objectively and quantitatively, the oral health status of individuals or groups. It provides a way of measuring, scoring and analyzing in numerical data, the specific oral conditions as seen in an individual or in a community.
Dental indices are needed in oral health surveys. Unless there is a numerical data available, it is difficult to ascertain the oral health care needs in a specific population. Indices are a useful way to:
- determine the prevalence of a particular condition in a population
- to determine the efficacy of certain oral health care devices, mechanisms or products
- to provide baseline data
- to educate and motivate individuals and groups in terms of oral health care maintenance
These indices may also be used in clinical practice to enlighten a patient about his or her dental condition and to compare the results of a dental treatment, or personal maintenance as against the data recorded during the first dental visit.
Indices can be reversible indices or irreversible indices depending upon the reversible or irreversible nature of the disease factor. Those conditions which cannot revert back to normal fall under the irreversible indices.
Papilla Marginal and Attached Gingival Index (PMA)
It is a measure of the incidence and severity of gingivitis in a given population based on the examination and rating of the degree of involvement of the interdental papilla and the marginal and attached portions of gingiva in each individual.
This dental index was developed by Schour and Massler. They gave a score of 0 to 5 depending upon the severity of disease in the gingiva. This index is no longer actively used.
Plaque Index (PI)
- developed by Silness and Loe
- The thickness of plaque at gingival margins is assessed
- The tooth surfaces examined are: facial, lingual (or palatal), mesial and distal
- A plaque disclosing agent may be used
- 0 = no plaque present
- 1 = a thin film of plaque can be distinguished
- 2 = a moderate layer of plaque on tooth surfaces with little may or may not be present in the gingival pocket
- 3 = abundant layer of plaque on the tooth surfaces and within the pocket
- The total of all four surfaces is added up, and divided by the number of tooth surfaces examined. This gives the PI score for each tooth.
- The total scores of all teeth are totalled and divided by the number of teeth examined. This gives the PI score for the individual.
- The result may be calculated as follows:- 0 = excellent, 0.1 to 0.9 = good, 1.0 to 1.9 = fair and 2 to 3 = poor
Oral Hygiene Index (OHI)
Oral hygiene index developed by Greene, Vermillion and and Waggenor, measures the overall oral hygiene. It divides the dentition into six parts, and the surface with the greater amount of plaque or calculus is taken into consideration. Thus twelve surfaces are calculated.
It is further divided into : Debris Index (DI) and Calculus Index (CI)
Debris Index (DI):
Debris is the soft, movable, foreign matter consisting of bacterial plaque and food debris.
- 0 = no debris or stain
- 1 = debris not covering more than 1/3rd of the tooth surface
- 2 = debris between 1/3rd and 2/3rd of tooth surface
- 3 = debris more than 2/3rd of the tooth surface
Calculus Index (CI):
Calculus is the hard, stony, calcified deposit of inorganic material on the tooth surfaces.
- 0 = no calculus
- 1 = calculus not covering more than 1/3rd of the tooth surface
- 2 = calculus covering between 1/3rd to 2/3rd of the tooth surface
- 3 = calculus covering more than 2/3rd of the tooth surface
The final score is calculated by adding the scores for each tooth divided by the number of sextants examined. The total scores of the DI and CI give the score of the OHI. The lowest possible score is 0, and the maximum score is 12.
Gingival Index (GI):
The three major parameters that the gingival index measures are the color, consistency and bleeding on probing. This index was also developed by Loe and Silness.
The gingiva is tested for all the three parameters with the help of a probe. The following method of scoring is used:
- 0 = normal gingiva, coral pink color, and no bleeding on probing
- 1 = mildly inflamed gingiva, no bleeding on probing
- 2 = moderately inflamed gingiva, with soft texture and moderate bleeding on probing
- 3 = severely inflamed gingiva, ulcerated, soft with spontaneous bleeding. If the color is not red, nor is the gingiva ulcerated, but there is spontaneous bleeding, the score is still considered to be 3.
Each surface is given a score. The scores are added up, and divided by four. The new total is divided by 12, and this gives the GI for the individual. 0 = excellent health of gingiva, 0.1 to 1 = good, 1.1 to 2 = fair, 2.1 to 3.0 = poor health of gingiva.
Periodontal Index (PI)
This index developed by Russel, is somewhat more comprehensive and thorough as compared to the gingival index. Not only does it consider the appearance of the oral tissues, it also stresses upon the functionality of the tooth.
- 0 = Normal tissues
- 1 = Mild gingivitis which does not circumscribe the tooth
- 2 = Gingivitis which circumscribes the tooth but there is no apparent break in the epithelial attachment
- 6 = gingivitis with pocket formation but there is no loss of function. The tooth is firm.
- 8 = Severely destroyed epithelial attachment, deep gingival pockets, and loss of function with mobility in the tooth.
Each tooth is assigned a score, and the scores are added up. The total is then divided by the number of teeth examined.
- 0 to 0.2 = good health
- 0.3 to 0.9 = mild gingivitis
- 0.7 to 1.9 = early periodontitis
- 1.6 to 5 = established periodontitis
- 3.8 to 8 = terminal periodontitis
Gingival Bleeding Index (GBI)
This index developed by Carter and Barnes, is used to determine the gingival bleeding. An unwaxed dental floss is used to measure the gingival bleeding index. A full complement of teeth has 28 proximal surfaces. The floss is passed in between the gingival sulcus on each side of the dental papilla. There should be no overt force exerted. The total number of bleeding surfaces is divided by the total number of surfaces examined, and a final score is arrived at.
Mobility Index (MI)
This index is used to measure the mobility of teeth. Developed by Grace and Smales, it scores in the following manner.
- 0 = no mobility
- 1 = mobility present but less than 1 mm buccolingually
- 2 = mobility more than 1 mm buccolingually but less than 2 mm
- 3 = severe mobility more than 2 mm, and present both buccolingually and vertically into the socket
Dean’s Dental Fluorosis Index (DFI)
Dental fluorosis is the presence of discolorations or defects on enamel, caused to do either faulty enamel production or less enamel production. Fluorosis presents in a varied number of ways. Sometimes seen only as small pits or striae on enamel surfaces, or milky white frosted lesions, or chalky appearances to grossly malformed teeth, these occur because of malnutrition at the time of teeth formation. The anterior teeth are most commonly affected and the molars are least commonly affected.
For the purpose of a survey, the two most severely affected teeth are selected. If the involvement of the two is unequal, the less severely affected of the tooth is selected for scoring.
- 0 = normal enamel
- 1 = questionable mostly normal looking enamel with tiny flecks or spots of white lesions seen
- 2 = very mild opaque milky white patches covering not more than 1/4th the tooth surface examined
- 3 = mild clinically visible milky white patches covering 50% of the tooth surface
- 4 = moderate brownish stains and some amount of deformity causing visible disfigurement
- 5 = severe the tooth may be so badly affected by fluorosis that the normal shape of the tooth may be altered. The teeth appear brown and mottled with widespread corroded appearance
Decayed Missing and Filled Teeth Index (DMFT)
This is a caries index. The prevalence of caries in a population can be defined using DMFT. Careful examination with a mirror and probe is carried out to find small carious lesions. It is prudent to carefully check for tooth colored fillings to arrive at the accurate picture. Each tooth is assigned a score and all the scores are indicated in boxes on a DMFT chart.
- 0 = no caries present. Fluorotic areas, and those with hard white lesions are to be ignored
- 1 = caries is present. If the crown is affected, the crown is assigned the score of 1. If the root is affected then the root is assigned 1. Where the crown is entirely destroyed by decay but the root is present, the crown and root both are given a score of 1.
- 2 = Filled teeth with secondary caries
- 3 = filled teeth without caries. If a tooth is crowned because of a previous carious lesion, it is given a score of 3. If however a crown is present as an abutment or for aesthetic reasons, it is scored as 7.
- 4 = A tooth missing because of decay. Only crowns are recorded as 4. The roots of such missing teeth are designated a 7 or 9.
- 5 = A tooth missing for any reason other than decay
- 6 = teeth on which sealant has been placed
- 7 = Tooth which is a part of a fixed bridge. It is also used to denote a root replaced by an implant. Teeth that have been restored by bridge pontics are scored 4 or 5. The roots of such teeth are scored as 9.
- 8 = This is used for a space where the permanent tooth is unerupted but the primary tooth is not present. In case of a root, the surface of which is not visible in the mouth, the root is assigned an 8.
- 9 = A tooth which cannot be scored because of reasons such as orthodontic treatment. It also applies to the root of a tooth which has been extracted. The crowns of such extracted teeth will be assigned a 4 or a 5.
- T = trauma.
To arrive at score the total number of carious, missing or filled teeth are calculated. For primary teeth the index is called ‘deft’ or ‘defs’ (decayed extracted filled)
Dr. Gauri S. Kekre (B.D.S., M.B.A.)
A dentist by profession and a writer by choice, she has worked in the field of dentistry for over six years. Her passion lies in learning more about her profession and making her knowledge useful for everyone. She hopes that she will one day be successful in her endeavor to make proper oral hygiene the most understood and followed practice in as many households as possible.