Early and Interceptive Orthodontics
What the exam tests
When to screen, which problems justify early intervention, and what the evidence says about two-phase treatment.
Core rules
- First orthodontic screening by age 7 (AAO/AAPD), which allows interception of crossbites, functional shifts, severe crowding, and airway concerns.
- Clear indications for early treatment: anterior or posterior crossbite with functional shift, ectopic eruption, impacted teeth, severe overjet with trauma risk, deep bite with palatal impingement, oral habits, and space maintenance after premature loss.
- Interceptive tools: 2×4 appliances, removable or fixed expansion, quad helix and RPE, lip bumper, serial extraction, space maintainers, habit appliances, and face mask for Class III.
- Evidence: early Class II treatment reduces overjet and trauma risk but usually does not shorten total treatment time; one-phase treatment is often acceptable. Face mask therapy in Class III produces short-term skeletal change with variable relapse.
- Rapid palatal expansion separates the midpalatal suture; the amount of skeletal versus dental expansion varies with age.
Worked example
An 8-year-old with an anterior crossbite and lateral shift to the right, adequate arch length. Reasoning: this is likely a pseudo-Class III from occlusal interference; removing the interference or using a simple removable appliance may correct it. If a true skeletal Class III is suspected (concave profile, family history), face mask therapy is considered, with clear discussion of relapse.
Traps
- Claiming expansion grows the mandible.
- Treating every Class II early without evidence of benefit.
- Serial extraction without a confirmed arch length deficiency.
- Missing that a functional shift can mask or mimic a skeletal discrepancy.