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6C Caries-free Children
Description | Specific Indicators | Corresponding Mandatory Objectives | Corresponding National Indicators | Data Sources |  Alternative Data Sources | ICD Codes | Analysis Check List | Method of Calculation |  Basic Categories | Indicator Comments | Cross-References to Other Sections | References  


  • The percentage of the children at school entry who have never had any cavities.



Dental, teeth, child, decay, cavities, caries, DIS, oral health


Specific Indicators

  •  Percentage caries-free


Corresponding Mandatory Objectives



Corresponding National Indicators



Data Sources (see Data Resources: Data Sources)

Numerator & Denominator:
Ontario Dental Indices Survey
Original source:
Ontario Dental Indices Survey, [Public Health Unit]
Distributed by: Public Health Unit
Suggested citation (see
Data Citation Notes):
Dental Indices Survey [years], [Public Health Unit], Extracted: [date]


Survey Questions



Analysis Check List
  • Determine what sampling methodology was used within a health unit before making comparisons of the DIS over time or with other health units.
  • Caries-free is defined as having all teeth coded in the WHO Modified Index used in the DIS as either 00 (sound) or 01 (sound with sealant)1.


Method of Calculation 


total number of children at school entry who have never had a cavity

* 100

total number of kindergarten children surveyed



Basic Categories
  • Geographic areas: public health unit.


Indicator Comments
  • The Latin word for caries means rottenness. Dental caries is a multifactorial disease and results from a combination of four main factors: host and teeth factors; microorganisms in dental plaque (principally Streptococcus mutans); sugar; and time, since the development of dental caries is a slow process that can take up to four years.2

  • Although dental caries have always been present in humans, levels remained low until the end of the 17th century when prevalence of dental caries increased in developed countries. The increase continued until the early 1970s; levels have since been declining. There was a break in the increase during the mid-1940s and early 1950s which coincided with a reduced availability of sugar because of food rationing during and after World War II.2

  • The DIS uses the WHO definition of caries:
    n 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 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.”1

  • A child who is considered to be caries-free because of a deft/DMFT Index of zero does not mean that the child is "caries-resistant" – they are merely caries-free at the time of survey. The child may have early stage caries not visible to the naked eye (surveys do not generally use radiographs) or may have had decay (d) and/or restorations (f) in their primary teeth which have now exfoliated. However, caries immune is often used interchangeably with caries-free.3

  • Although public health units are required by Mandatory Health Programs and Services Guidelines to conduct the DIS for all school entrants, many do not have sufficient resources and instead sample only some of the children. Each public health unit uses a different methodology depending upon local resources. As a result, the DIS is not comparable across health units. Comparisons within a health unit over time may be appropriate as long as the sampling methodology has remained consistent.

  • Because the DIS is conducted for children at school entry (Junior Kindergarten and Senior Kindergarten) throughout the school year from September to June, children can range in age from 3 to 6 years.

  • The Mandatory Health Programs and Services Guidelines have the objective “to reduce the prevalence of dental diseases in children and youth”. While this indicator relates to the objective, it is not a direct measure because it assesses positive dental health rather than dental disease.

  • The draft Mandatory Health Programs and Services Guidelines of January 2003 had the following objective: “An increased proportion of children and youth will have good oral health”. This indicator corresponds to this objective.

  • Oral disorders can have a significant impact on general health and well-being:
    n Dental decay is caused by bacterial infection. It is one of the most common disorders of childhood. It can cause pain, poor sleep and poor eating habits in children. Dental decay can be a contributing factor in “failure to thrive” whereby children have low weight and height for their age.4
    n Periodontal disease, a chronic infection caused by bacteria that accumulate in plaque, has been linked to various diverse health problems including pre-term low birth weight babies, heart disease, stroke, pneumonia, and chronic respiratory disease.4
    n Poor oral health can lead to poor nutrition and decreased quality of life due to pain, and chewing and speech problems.4

  • There is a strong link between oral health and income. Low-income children and new immigrants are most likely to have poor oral health.4

  • Percent caries immune for Ontario for age 5 years5:
    1972 – 42.0%
    1974 – 44.0%
    1976 – 46.0%
    1978 – 51.0%
    1980 – 50.8%
    1982 – 56.3%
    1984 – 60.4%
    1986 – 65.8%
    1988 – 68.3%
    1990 – 68.4%
    1993 – 68.6%


Cross-References to Other Sections


  1. Ontario Ministry of Health. Dental Indices Software Program Manual. December 9, 1997.
  2. Whelton H, O'Mullane DM. Public health aspects of oral diseases and disorders: dental caries. In Pine CM (ed.) Community Oral Health. Oxford: Reed Educational & Professional Publishing Ltd, 1997.
  3. Burt BA, Elund SA. Dentistry, Dental Practice and the Community. Philadelphia: W.B. Saunders Company, 1999.
  4. Locker D, Matear D. Oral disorders systemic health, well-being and the quality of life: A summary of recent research evidence.

Date of Last Revision: November 10, 2004

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