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Tooth status

Extracts of the Third edition of
"Oral Health Surveys - Basic methods", Geneva 1987.

Please observe that the Fourth edition is available, see Oral Health Methods and Indices.
This extract concerns: Individual tooth status and Criteria for diagnosis and coding (Caries). Pages 34 - 37.


Individual tooth status and treatment need (boxes 31-94)

Method of assessing dental caries

(boxes 31-94)

The examination for dental caries should be conducted with a plane mouth mirror and an explorer. Radiography is not recommended because of the impracticability of using the equipment in all situations. It should be realized, however, that without radiographic information the need for restorative care will be underestimated. The extent of this underestimation varies with disease prevalence and the number of restorations in the population. In populations with very low, low,or moderate caries levels, the underestimate is likely to be of the order of 3-5 %. Even in populations with high prevalence of disease, where a large amount of restorative care has been provided, the underestimate will only be of the order of 10-15%.

Examiners should adopt a systematic approach to the examination for dental caries, proceeding in an orderly manner from one tooth or tooth space to the adjacent tooth or tooth space. A tooth should be considered present in the mouth when any part of it is visible or can be touched with the tip of the explorer without unduly displacing soft tissue. If a permanent and a primary tooth occupy the same tooth space, the status of the permanent tooth only should be recorded.

Dentition status.

A numerical coding system is used for recording the status of permanent teeth and an alphabetical coding system for primary teeth: boxes 31-46 are used for upper teeth and boxes 63-78 for lower teeth. Note that boxes pertaining to premolars or primary molars, cuspids and incisors are used for both primary and permanent teeth. A distinction is made solely by the use of alphabetical or numerical codings. An entry must be made in every box on the chart. Codes for the dental caries status of primary and permanent teeth are as follows:
Permanent tooth                               Primary tooth 
     code                                          code

        0        Sound ..............................A

        1        Decayed.............................B

        2        Filled, with decay ..... ...........C

        3        Filled, no decay ...................D

        4        Missing, as a result of caries......E

        5        Missing, any other reason ..........-

        6        Sealant, varnish ...................F

        7        Bridge abutment or special crown ...G

        8        Unerupted tooth ....................-

        9        Excluded tooth .....................-

Criteria for diagnosis and coding (primary tooth codes within parentheses) are:

0 (A). Sound tooth.

A tooth is recorded as sound if it shows no evidence of treated or untreated clinical caries. The stages of caries that precede cavitation, as well as other conditions similar to the early stages of caries, are excluded because they cannot be reliably diagnosed. Thus, teeth with the following defects, in the absence of other positive criteria, should be coded as sound:
  • white or chalky spots;
  • discoloured or rough spots;
  • stained pits or fissures in the enamel that catch the explorer but do not have a detectably softened floor, undermined enamel, or softening of the walls;
  • dark, shiny, hard, pitted areas of enamel in a tooth showing signs of moderate to severe fluorosis.
All questionable lesions should be coded as sound.

1 (B). Decayed tooth.

Caries is recorded as present when a lesion in a pit or fissure, or on a smooth tooth surface, has a detectably softened floor, undermined enamel or softened wall. A tooth with a temporary filling should also be included in this category. On approximal surfaces, the examiner must be certain that the explorer has entered a lesion. Where any doubt exists, caries should not be recorded as present.

2 (C). Filled tooth with decay.

A tooth is scored as filled with decay when it contains one or more permanent restorations and one or more areas that are decayed. No distinction is made between primary and secondary caries (i.e., whether or not the carious lesions are in physical association with the restoration(s)).

3 (D). Filled tooth with no decay.

Teeth are considered filled without decay when one or more permanent restorations are present and there is no secondary (recurrent) caries or other area of the tooth with primary caries. A tooth with a crown placed because of previous decay is recorded in this category. A tooth that has been crowned for reasons other than decay, e.g., trauma or as a bridge abutrnent, is recorded as "bridge abutment or special crown" and coded 7 (G).

4 (E). Tooth missing due to caries.

This score is used for permanent or primary teeth that have been extracted because of caries. For missing primary teeth, this score should be used only if the subject is at an age when normal exfoliation would not be a sufficient explanation for absence.

In some age groups, it may be diffcult to distinguish between unerupted teeth (code 8) and extracted teeth. Basic knowledge of tooth eruption patterns, the status of the corresponding contralateral tooth, the appearance of the alveolar ridge in the area of the tooth space in question, and the caries status of other teeth in the mouth may provide helpful clues in making a differential diagnosis between unerupted and extracted teeth. It is emphasized that code 4 should not be used for teeth judged to be missing for any reason other than caries. For convenience, in fully edentulous arches, a single "4" should be placed in boxes 31 and 46 and/or 63 and 78, as appropriate, and the respective pairs of numbers linked with straight lines.

5. Permanent tooth missing for any other reason.

This code is used for permanent teeth judged to be absent congenitally, or extracted for orthodontic reasons or because of trauma, etc. This score is also used for permanent teeth that are judged to have been extracted because of periodontal disease.

As for code 4, two entries of code 5 can be linked by a line in cases of fully edentulous arches.

6 (F). Sealant

This code is used for teeth in which a fissure sealant has been placed on the occlusal surface; or for teeth in which the occlusal fissure has been enlarged with a rounded or "flame-shaped" bur, and a composite material placed. If a tooth with a sealant has decay, it should be coded as 1 (decayed).

7 (G). Bridge abutment or special crown.

This code is used to indicate that a tooth forms part of a fixed bridge, i.e., is a bridge abutment. This code can also be used for crowns placed for reasons other than caries. Note: Missing teeth replaced by a bridge are coded 4 or 5, as for other missing teeth.

8. Unerupted tooth.

This classification is restricted to permanent teeth and used only for a tooth space with an unerupted permanent tooth but without a primary tooth. Teeth scored as unerupted are, of course, excluded from all calculations concerning dental caries. For differential diagnosis between extracted and unerupted teeth, see code 4.

9. Excluded tooth.

This code is used for any tooth that cannot be examined.

Decayed, Missing, and Filled Teeth Index (DMFT).
Information on the Decayed, Missing, and Filled Teeth Index (DMFT) can be calculated from the information in boxes 31 to 46 and 63 to 78. The D-component includes all teeth with codes 1 or 2. The M-component comprises teeth with code 4 in subjects under 30 years of age, and teeth coded 4 and 5 for subjects 30 years and older, i.e., missing due to caries or for any other reason.

Note: Previously only teeth missing due to caries were included in the DMFT index and in its M-component. The F-component includes only teeth with code 3. The basis for DMFT calculations is 32, i.e., all permanent teeth including wisdom teeth. Teeth with code 6 (sealant) or code 7 (crown, bridge abutment or element) are not included in the DMFT.

Last updated by Gisela Ladda Tayanin