Tx of Class I Malocclusion

Class I: Tx Options Arch-Space Discrepancy 1. Crowding: 2. Spacing

1. Arch expansion non-extraction, extraction, IPR 2. Close spaces power chain, retention concerns, evaluate for Bolton discrepancy, potential restorations

Additional Ways to Resolve Crowding: 1. IPR-Interproximal Reduction 2. Mx Skeletal Expansion

1. Helps in minimal crowding space (<4mm). Polishing strips, discs. Common in lower anteriors. 2. RPE or RME. True expansion vs. dental. Help correct moderate crowding.

Option 1: 1st PM extractions Option 2: 2nd PM extractions

1. Maximum posterior anchorage, maximum retraction of anterior teeth 2. Less anchorage as compared to option 1. Less retraction of anterior teeth. More difficult to correct anterior crowding. "Wedge" theory for open bite tx's.

Guideline for Extractions: 1. Less than 4 mm crowding= 2. 5-9 mm crowding= 3. >10 mm crowding=

1. no extraction. Only if severe incisor protrusion, severe vertical discrepancy. Consider IPR. 2. Non-extraction or extraction. Extraction depends on patient's hard and soft-tissue characteristics and incisor positions or angulation. Non-extraction usually requires transverse expansion. 3. Premolar extraction almost always required.

Treatment Timing Class I: 1. No need for growth modification 2. Most efficient if started ___ 3. Minor problems can probably be treated at any time 4. Transverse problems are easier to treat earlier 5. Vertical growth problems may need to be addressed earlier

2. started in late mixed or permanent dentition

Factors to Consider when Tx Planning: 1. Chief complaint 2. Motivation: cooperation/compliance 3. Expectations: can you meet their expectations with tooth movement only? 4. Facial proportions and soft tissue: Jaw surgery? 5. Growth potential: If still growing can we take advantage of growth?

US Population: Class I