Orthodontics and Pediatric Dentistry
What this domain tests
Orthodontics and paediatric dentistry test growth and eruption, interceptive treatment, space management, pulp therapy in primary teeth, behaviour management, and dental trauma.
Core rules
- Eruption: first permanent molar at 6 years, central incisors 6-7, lateral 7-8, first premolar 9-10, canine 11-12, second premolar 11-12, second molar 12-13.
- Leeway space is about 1.5 mm per side in the mandible and 0.9 mm in the maxilla; preserving it prevents crowding.
- Space maintenance: band and loop for a single premature loss with the permanent molar erupted; distal shoe when the first permanent molar has not erupted.
- Interceptive options: elimination of habits, expansion for crossbite, serial extraction in selected cases, and referral around age 7 for Class III or severe discrepancy.
- Primary pulp therapy: pulpotomy for a vital, symptom-free tooth with reversible inflammation; pulpectomy for irreversible pulpitis; never when radicular pathosis or a sinus tract is present.
- Stainless steel crowns for multi-surface caries and after pulpotomy.
- Trauma: an avulsed permanent tooth is replanted immediately and splinted flexibly for two weeks; a primary tooth is not replanted.
Worked example
An 8-year-old loses 75 early; 36 has not erupted; space is closing. Reasoning: the distal shoe maintains space until the first molar erupts; a band and loop cannot be used because there is no distal abutment yet.
Traps
Placing a space maintainer where no space loss is likely; pulpotomising a tooth with a sinus tract; extracting a primary canine without an orthodontic plan.