2. Epidemiology Flashcards
What is Epidemiology?
- “Epidemiology is a method of reasoning about disease that deals with biological inference derived from observations of disease phenomena in population groups” - Lilienfield 1978
- Epidemiology is the quantitative analysis of the circumstances under which disease processes, including trauma, occur in population groups, factors affecting their incidence, distribution, and the host response and use of this knowledge in prevention and control - Evans 1979
- Epidemiology is the study (scientific, systematic, and data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (neighborhood, school, city, state, country, global)
What is prevalence?
This is the proportion of individuals with disease (cases) in a population at a specific point in time
What is incidence?
This is the # or proportion of individuals in a population who experience new disease during a specific period
What are trends?
These are the changes or differences in the prevalence or incidence of disease with respect to time, location, or socioeconomics
What is the National Child Oral Health Study?
- ‘snap shot’ of child oral health
- 5-14yr old children
- Interviews and standardised dental examinations
- Last NCOHS conducted in 2012-14
What is the National Survey of Adult Oral Health?
- ‘snap shot’ of adult oral health
- ‘representative’ cross-sectional sample of people aged over 15yrs
- Interviews and standardised dental examinations
- Last NSAOH was conducted in 2017-18
What is the National Dental Telephone Interview Survey?
- random sample of the Australian population
- Involves Australians 5 years and over, conducted ever 2-3yrs
- Explores oral health status, social and demographic information, and dental visiting behaviours
- Surveys were conducted in 1994, 1996, 1999, 2002, 2005, 2008, 2010 and 2013
What are the ideal properties of an epidemiological index?
- Valid: An index must be designed to measure the aspect of disease that it is intended to measure and correspond to clinical stages of the disease.
- Reliable: An index should be reproducible and repeatable, and should provide consistent measurement at any given time under a variety of conditions.
- Clear, Simple, Objective: An index should have clearly stated, unambiguous criteria with mutually exclusive categories, and should be simple enough for an examiner to memorize and score using the criteria.
- Quantifiable: An index must present data that can be numerically analyzed and treated. Group status should be expressed by distribution, mean, median, or other statistical measures.
- Sensitive: An index should identify small yet significant shifts in the condition studied.
- Acceptable: The use of the index should not be unnecessarily painful, time- demanding, or demeaning to subjects.
For DMFT what is the range of scores?
0-28 or 0-32 depending on whether 3rd molars are included
For DMFS, what its the range of scores?
0-128 or 0-148 depending on whether 3rd molars are included
What is the range of scores for dmft and dmfs?
- dmft scores range from 0-20
- dmfs scores range from 0-88
Calculating DMFT
Teeth that are not counted:
• unerupted, congenitally missing teeth or supernumerary teeth
• teeth removed for reasons other than dental caries
• primary teeth retained in the permanent dentition
• counting the 3rd molars is optional – 30% of population are missing 3rd molars !
Notes about ‘D’
• when a carious lesion(s) or both carious lesion(s) and a restoration are present, the tooth is recorded as a D
• eg recurrent/secondary caries under an existing restoration would be recorded as a D
Notes about ‘M’
• counted only when a tooth has been extracted due to caries ie not for orthodontic/periodontal reasons
Notes about ‘F’
• when a permanent or temporary filling is present, or when a filling is defective but not decayed
• teeth restored for reasons other than caries are not counted as an F
Limitations of DMFT
- extractions for reasons other than caries if included can overestimate caries experience (eg periodontal disease or orthodontic extractions)
- no information about teeth at risk (eg initial lesion vs deep lesion)
- equal weighting given to missing, untreated decay or well restored teeth
- irreversible - i.e you can be 60yrs old, having had only one restoration at 15yrs of age but you will still be considered ‘unhealthy’ with 0
What is the PUFA index?
clinical consequences of untreated dental caries
• Pulpal involvement
• Ulceration caused by dislocated tooth fragments
• Fistula
• Abscess
What is Pulpal Involvement (PUFA)?
Pulpal involvement, is recorded when the opening of the pulp chamber is visible or when the coronal tooth structures have been destroyed by the carious process and only roots or root fragments are left. No probing is performed to diagnose pulpal involvement
What are the levels of ICDAS?
What is the Nyvad Criteria?
Nyvad Criteria developed in 1999
Visual and tactile caries classification
Used to classify active vs inactive caries
a) Active non-cavitated lesion on smooth surface and b) occlusal surface
c) Inactive non-cavitated lesion on smooth surface and d) occlusal surface
e) Active and f) inactive lesion with microcavity on occlusal surface
g) Active and h) inactive cavitated lesion
What is CAST?
Caries Assessment Spectrum and Treatment
- aims to combine ICDAS II and DMFT
- covers a broader spectrum from sound through to tooth loss
- enables DMFT to also be calculated
- allows of groupings based on disease severity
- enables public health surveillance and change in disease burden
- unable to categorize active/inactive lesions
- does not provide treatment recommendations
