Extracts of the Fourth edition of
"Oral Health Surveys - Basic methods", Geneva 1997.
This extract concerns: Dentition status and Criteria for diagnosis and coding (Caries). Pages 39 - 44.
Dentition status and treatment need (boxes 66-161)
Method of assessing dental caries
The examination for dental caries should be conducted with a plane mouth mirror. Radiography for detection of approximal caries is not recommended because of the impracticability of using the equipment in all situations. Likewise, the use of fibre obtics is not recommented. Although it is realized that both these diagnostic aids will reduce the underestimation of the need for restorative care, the extra complication and frequent objections to exposure to radiation outweigh the gains to be expected.
Examiners should adopt a systematic approach to the assessment of dentition status and treatment needs. The examination should proceed 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. If a permanent and a primary tooth occupy the same tooth space, the status of the permanent tooth only should be recorded.
Both letters and numbers are used for recording dentition status. Boxes 66-97 are used for upper teeth and boxes 114-145 for lower teeth. The same boxes are used for recording both primary teeth and their permanent successors. An entry must be made in every box pertaining to coronal and root status. In the case of surveys of children, where the root status is not assessed, a code "9" (not recorded) should be entered in the box pertaining to root status.
Note: Considerable care should be taken to diagnose tooth-coloured fillings, which may be extremely difficult to detect.
Codes for the dentition status of primary and permanent teeth (crowns and roots) are given in the table below:
Filled, with decay
Filled, no decay
Missing, as a result of caries
Missing, any other reason
Bridge abutment, special crown or veneer/implant
Unerupted tooth (crown)/unexposed root
The Criteria for diagnosis and coding (primary tooth codes within parentheses) are:
0 (A). Sound crown.
A crown 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, a crown with the following defects, in the absence of other positive criteria, should be coded as sound:
- white or chalky spots;
- discoloured or rough spots that are not soft to touch with a metal CPI probe;
- stained pits or fissures in the enamel that do not have visual signs of undermined enamel, or softening of the floor or walls detectable with a CPI probe;
- dark, shiny, hard, pitted areas of enamel in a tooth showing signs of moderate to severe fluorosis.
- lesions that, on the basis of their distribution or history, or visual/tactile examination, appear to be due to abrasion.
A root is recorded as sound when it is exposed and shows no evidence of treated or untreated clinical caries. (Unexposed roots are coded 8.)
1 (B). Decayed crown.
Caries is recorded as present when a lesion in a pit or fissure, or on a smooth tooth surface, has an unmistakable cavity, undermined enamel, or a detectably softened floor or wall. A tooth with a temporary filling, or one which is sealed (code 6 (F)) but also decayed, should also be included in this category. In case where the crown has been destroyed by caries and only the root is left, the caries is judged to have originated on the crown and therefore scored as crown caries only. The CPI probe should be used to confirm visual evidence of caries on the occlusal, buccal and lingual surfaces. Where any doubt exists, caries should not be recorded as present.
Caries is recorded as present when a lesion feels soft or leathery to probing with the CPI probe. If the root caries is discrete from the crown and will require a separate treatment, it should be recorded as root caries. For single carious lesions affecting both the crown and the root, the likely site of origin of the lesion should be recorded as decayed. When it is not possible to judge the site of origin, both the crown and the root should be recorded as decayed.
2 (C). Filled crown, with decay.
A crown is considered filled, with decay, when it has one or more permanent restorations and one or more areas that are decayed. No distinction is made between primary and secondary caries (i.e., the same code applies whether or not the carious lesions are in physical association with the restoration(s)).
Filled root, with decay.
A root is considered filled, with decay, when it has one or more permanent restorations and one or more areas that are decayed. No distinction is made between primary and secondary caries.
In the case of fillings involving both the crown and the root, judgement of the site of origin is more difficult. For any restoration most likely site of the primary carious lesion is recorded as filled, with decay. When it is not possible to judge the site of origin of the primary carious lesion, both the crown and the root should be recorded as filled, with decay.
3 (D). Filled crown, with no decay.
A crown is considered filled, without decay, when one or more permanent restorations are present and there is no caries anywhere on the crown. A tooth that has been crowned because of previous decay is recorded in this category. (A tooth that has been crowned for reasons other than decay, e.g. a bridge abutment, is coded 7 (G).)
Filled root, with no decay.
A root is considered filled, without decay, when one or more permanent restorations are present and there is no caries anywhere on the root.
In the case of fillings involving both the crown and the root, judgement of the site of origin is more difficult. For any restoration involving both the crown and the root, the most likely site of the primary carious lesion is recorded as filled. When it is not possible to judge the site of origin, both the crown and the root should be recorded as filled.
4 (E). Missing tooth, as a result of caries.
This code is used for permanent or primary teeth that have been extracted because of caries and is recorded under coronal status. 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.
Note: The root status of a tooth that has been scored as missing because of caries should be coded "7" or "9".
In some age groups, it may be diffcult to distinguish between unerupted teeth (code 8) and missing teeth (code 4 and code 5). Basic knowledge of tooth eruption patterns, 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. 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 66 and 81 and/or 114 and 129, 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 periodontal disease, trauma, etc. As for code 4, two entries of code 5 can be linked by a line in cases of fully edentulous arches.
Note: The root status of a tooth scored 5 should be coded "7" or "9".
6 (F). Fissure 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 or B.
7 (G). Bridge abutment, special crown or veneer.
This code is used under coronal status 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 and for veneers or laminates covering the labial surface of a tooth on which there is no evidence of caries or a restoration.
Note: Missing teeth replaced by a bridge are coded 4 or 5, under coronal status, while root status is scored 9.
Implant. This code is used under root staus to indicate that an implant has been placed as an abutment.
8 (-). Unerupted crown.
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 excluded from all calculations concerning dental caries. This category does not include congenitally missing teeth, or teeth lost as a result of trauma, etc. For differential diagnosis between missing and unerupted teeth, see code 5.
This code indicates that the root surface is not exposed, i.e. there is no gingival recession beyond the CEJ.
T (T). Trauma (fracture).
A crown is scored as fractured when some of its surface is missing as a result of trauma and there is no evidence of caries.
9 (-). Not recorded.
This code is used for any erupted permanent tooth that cannot be examined for any reason (e.g. because of orthodontic bands, severe hypoplasia, etc.).
This code is used under root status to indicate either that the tooth has been extracted or that calculus is present to such an extent that a root examination is not possible.
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 66-97 and 114-145. 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 or 5 for subjects 30 years and older, i.e. missing due to caries or for any other reason. 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 coded 6 (fissure sealant) or 7 (bridge abutment, special crown or veneer/implant) are not included in calculations of the DMFT.