Orthodontics and Pediatric Dentistry
What the exam tests
Growth-aware malocclusion assessment, timing of interceptive treatment, and the special rules of primary and mixed dentition care, including dental trauma in children.
Core rules
- Angle's classification uses the first molar relationship: Class I mesiobuccal cusp of the upper first molar in the buccal groove; Class II the upper molar is mesial; Class III distal. Skeletal assessment uses cephalometrics, typically SNA 82±2°, SNB 80±2°, ANB 2±2°.
- First dental visit by age one or with the first tooth; orthodontic screening by age seven, when the first permanent molars and incisors have erupted and interceptive options exist.
- Preserve the leeway space in the mixed dentition; a band-and-loop or transpalatal arch maintains space after premature loss. Prolonged digit sucking that produces an anterior open bite and posterior crossbite may need an appliance.
- Early childhood caries: fluoride varnish, dietary and hygiene counselling, silver diamine fluoride or the Hall technique for arrested cavitated lesions, pulpotomy with MTA or formocresol for vital pulp exposure, pulpectomy for infected primary teeth.
- Avulsed primary teeth are not replanted - doing so risks damage to the developing permanent tooth. Permanent teeth are replanted immediately, held in milk or saline, and splinted flexibly for about two weeks.
Worked example
An 8-year-old avulses the upper right central incisor; extraoral dry time is 20 minutes and the apex is open. Reasoning: reposition quickly, splint flexibly for two weeks, check with radiographs, prescribe chlorhexidine and soft diet, and refer for revascularisation or apexification follow-up. Antibiotics are not automatic; tetanus status is checked.
Traps that cost marks
- Replanting a primary incisor.
- Extracting a primary molar without a space maintainer plan.
- Misclassifying a Class I case with an anterior crossbite as Class III without checking the molar relationship.