MJDF Dental Public Health & Evidence-Based Dentistry 1 — Questions and Answers
Question 1: What is the DMFT index used to measure at the population level?
- Caries experience in the permanent dentition — Decayed, Missing (due to caries), Filled Teeth — used to compare populations and monitor trends (Correct answer)
- Active caries only
- Periodontal disease burden
- Denture use in populations
Correct answer: Caries experience in the permanent dentition — Decayed, Missing (due to caries), Filled Teeth — used to compare populations and monitor trends
DMFT (and its primary tooth equivalent dmft) quantifies lifetime caries experience, allowing comparison between countries, regions, and time periods; the WHO target has been 'DMFT ≤1 at age 12' as a key global benchmark.
Question 2: What is the current WHO target for DMFT at age 12?
- DMFT ≤1 at age 12 (longstanding target, with newer frameworks using multiple indicators) (Correct answer)
- DMFT = 0
- DMFT ≤ 5
- No WHO target exists for children
Correct answer: DMFT ≤1 at age 12 (longstanding target, with newer frameworks using multiple indicators)
The WHO global oral health target of DMFT ≤1 at age 12 has been a benchmark since 1981; newer WHO frameworks use multiple indicators beyond DMFT, but this remains a key internationally recognised standard.
Question 3: What is the main limitation of the DMFT index in assessing oral health need?
- It does not distinguish between active and treated disease, overestimates need if many filled teeth, and underestimates need if many extractions occur instead of restoration (Correct answer)
- It only records caries in children
- It ignores periodontal disease
- It cannot be used for surveys
Correct answer: It does not distinguish between active and treated disease, overestimates need if many filled teeth, and underestimates need if many extractions occur instead of restoration
DMFT counts fillings as equal to decay (both contribute equally to the score), missing teeth may mask different care patterns (extraction vs. restoration), and it does not capture disease severity or impact on quality of life.
Question 4: What is the oral health impact profile (OHIP-14) used to measure?
- Oral health-related quality of life (OHRQoL) — how oral conditions affect physical, psychological, and social wellbeing (Correct answer)
- Caries severity
- Periodontal disease staging
- Number of teeth present
Correct answer: Oral health-related quality of life (OHRQoL) — how oral conditions affect physical, psychological, and social wellbeing
OHIP-14 is a 14-item validated questionnaire measuring the functional, psychological, and social impacts of oral conditions on quality of life — an essential patient-centred outcome measure.
Question 5: What is the purpose of water fluoridation in public health dentistry?
- Population-level caries prevention — optimal fluoride (0.7–1.0 mg/L in UK) reduces DMFT by approximately 25–30% without significant health risk (Correct answer)
- Treatment of existing caries
- Whitening of teeth at the population level
- Prevention of periodontal disease
Correct answer: Population-level caries prevention — optimal fluoride (0.7–1.0 mg/L in UK) reduces DMFT by approximately 25–30% without significant health risk
Community water fluoridation adjusts fluoride concentration to 0.7–1.0 ppm (mg/L), providing a constant low-level fluoride exposure that reduces caries incidence across all socioeconomic groups.
Question 6: What is the main determinant of oral health inequalities in the UK?
- Socioeconomic deprivation — lower income groups have higher DMFT, less dental service access, and poorer oral health outcomes (Correct answer)
- Genetics alone
- Ethnicity only
- Rural vs. urban location
Correct answer: Socioeconomic deprivation — lower income groups have higher DMFT, less dental service access, and poorer oral health outcomes
Socioeconomic deprivation is the strongest predictor of poor oral health in the UK; children from deprived areas have consistently higher caries rates, more extractions under GA, and less access to preventive dental care.
MJDF Dental Public Health & Evidence-Based Dentistry 1
What is the DMFT index used to measure at the population level?