Oral Health Country/Area Profile Project – CAPP

DMFT and DMFS describe the amount - the prevalence - of dental caries in an individual. DMFT and DMFS are methods to numerically express the caries prevalence and are obtained by calculating the number of

• Decayed (D)
• Missing (M)
• Filled (F)
• teeth (T) or surfaces (S)

It is thus used to get an estimation illustrating how much the dentition until the day of examination has become affected by dental caries. It is either calculated for 28 (permanent) teeth, excluding 18, 28, 38 and 48 (the "wisdom" teeth) or for 32 teeth (The Third edition of "Oral Health Surveys - Basic methods", Geneva 1987, recommends 32 teeth).

Thus:

How many teeth have caries lesions (incipient caries not included)?
How many teeth have been extracted?
How many teeth have fillings or crowns?
The sum of the three figures forms the DMFT value. For example: DMFT of 4-3-9=16 means that 4 teeth are decayed, 3 teeth are missing and 9 teeth have fillings. It also means that 12 teeth are intact.

Note: If a tooth has both a caries lesion and a filling it is calculated as D only. A DMFT of 28 (or 32, if "wisdom" teeth are included) is the maximum, meaning that all teeth are affected.

A more detailed index is DMF calculated per tooth surface, DMFS. Molars and premolars are considered to have 5 surfaces, front teeth 4 surfaces. Again, a surface with both caries and filling is scored as D. Maximum value for DMFS comes to 128 for 28 teeth.

For the primary dentition, consisting of a maximum of 20 teeth, the corresponding designations are "deft" or "defs", where "e" indicates "extracted tooth".

In caries data for adults, the following designations are used:

• DMFT: Mean number of decayed, missing or filled teeth
• %DMFT: Percentage of population affected with dental caries
• DT: Mean number of decayed teeth
• %D: Percentage with untreated decayed teeth
• MT: Mean number of missing teeth
• MNT: Mean number of teeth
• %Ed: Percentage edentulous.

A detailed analysis of the caries situation in many countries show that there is a skewed distribution of caries prevalence - meaning that a proportion of 12-year-olds still has high or even very high DMFT values even though a proportion is totally caries-free. Clearly, the mean DMFT value does not accurately reflect this skewed distribution leading to the incorrect conclusion that the caries situation for the whole population is controlled, while in reality, several individuals still have caries. The Significant Caries Index was introduced in order to bring attention to the individuals with the highest caries values in each population under investigation.

Individuals are sorted according to their DMFT values to calculate the Significant Caries Index. The one-third of the population with the highest caries scores is selected. The mean DMFT for this subgroup is calculated. This value is the SiC Index.

• References

• Bratthall D. Introducing the Significant Caries Index together with a proposal for a new oral health goal for 12-year-olds
• Nishi M. et al. Caries experience of some countries and areas expressed by the Significant Caries Index.

Indicators

Three indicators of periodontal status are used for this assessment:

1. gingival bleeding
2. calculus
3. periodontal pockets

A specially designed lightweight CPI probe with a 0.5-mm ball tip is used, with a black band between 3.5 and 5.5 mm and rings at 8.5 and 11.5 mm from the ball tip.

Sextants

The mouth is divided into sextants defined by tooth numbers: 18-14, 13-23, 24-28, 38-34, 33-43, and 44-48. A sextant should be examined only if there are two or more teeth present and not indicated for extraction. (Note: This replaces the former instruction to include single remaining teeth in the adjacent sextant.)

Index teeth

For adults aged 20 years and over, the teeth to be examined are:

• 17/16, 11, 26/27
• 47/46, 31, 36/37

The two molars in each posterior sextant are paired for recording, and if one is missing, there is no replacement. If no index teeth or tooth is present in a sextant qualifying for examination, all the remaining teeth in that sextant are examined and the highest score is recorded as the score for the sextant. In this case, the distal surfaces of the third molars should not be scored.

For subjects under the age of 20 years, only six teeth - 16,11, 26, 36, 31 and 46 - are examined. This modification is made in order to avoid scoring the deepened sulci associated with eruption as periodontal pockets. For the same reason, when children under the age of 15 are examined, pockets should not be recorded, i.e. only bleeding and calculus should be considered.

Sensing gingival pockets and calculus

An index tooth should be probed, using the probe as a "sensing" instrument to determine pocket depth and to detect subgingival calculus and bleeding response. The sensing force used should be no more than 20 grams. A practical test for establishing this force is to place the probe point under the thumbnail and press until blanching occurs. For sensing subgingival calculus, the lightest possible force that will allow movement of the probe ball tip along the tooth surface should be used.

When the probe is inserted, the ball tip should follow the anatomical configuration of the surface of the tooth root. If the patient feels pain during probing, this is indicative of the use of too much force.

The probe tip should be inserted gently into the gingival sulcus or pocket and the total extent of the sulcus or pocket explored. For example, the probe is placed in the pocket at the distobuccal surface of the second molar, as close as possible to the contact point with the third molar, keeping the probe parallel to the long axis of the tooth. The probe is then moved gently, with short upward and downward movements, along the buccal sulcus or pocket to the mesial surface of the second molar, and from the disto-buccal surface of the first molar towards the contact area with the premolar. A similar procedure is carried out for the lingual surfaces, starting distolingually to the second molar.

Examination and recording

The index teeth, all remaining teeth in a sextant where there is no index tooth, should be probed and the highest score recorded in the appropriate box.

The codes are:

0 Healthy

1 Bleeding observed, directly or by using mouth mirror, after probing

2 Calculus detected during probing, but all the black band on the probe visible

3 Pocket 4 - 5 mm (gingival margin within the black band on the probe)

4 Pocket 6 mm or more (black band on the probe not visible)

X Excluded sextant (less than two teeth present)

9 Not recorded

Examples of coding are both illustrated and photographed in "Oral Health Surveys".