Paediatric dentistry, orthodontics and dental public health
Ages, indices and prevention
Paediatric questions test chronology and prevention. Know eruption timing (primary incisors around 6–10 months, primary dentition complete by about 2.5–3 years; first permanent molars and lower incisors around 6 years) and the difference between exfoliation dates and eruption dates. Prevention is high-yield: fluoride toothpaste of at least 1,000 ppm from eruption of the first tooth, 1,350–1,500 ppm from age 3, and 2,800 ppm for higher-risk children over 10; fluoride varnish 22,600 ppm (2.26% NaF) twice yearly from age 3, more often in high-risk children; fissure sealants on caries-prone permanent molars. Understand molar–incisor hypomineralisation, early childhood caries, behaviour management and dental trauma - avulsion management, storage media and splinting.
Orthodontics: classify the incisor relationship (I, II division 1 and 2, III) and distinguish skeletal from dental patterns using SNA, SNB and ANB. In the UK, need is measured with IOTN - Dental Health Component grades 1–5 and Aesthetic Component 1–10 - and treatment timing matters (interceptive, growth modification, camouflage versus orthognathic surgery).
Dental public health asks about measures and study design: prevalence versus incidence, dmft/DMFT and its components, the ICON and Nyvad systems, Wilson and Jungner screening criteria, water fluoridation, and the social gradient in caries. Be able to calculate from a table.
Worked example: a child has two decayed primary molars, one filled primary molar and one primary molar missing for caries. The dmft is 2 + 1 + 1 = 4; a tooth lost to trauma would not count in the 'm' component.
Traps: mixing primary and permanent eruption ages, quoting adult fluoride concentrations for children, and confusing IOTN DHC with AC.