Orthodontics - IOTN

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Index of Orthodontic Treatment Need (IOTN). DENTAL HEALTH COMPONENT (DHC)

Grade 1 (none)

Extremely minor malocclusions, including displacements <1 mm

Grade 2 (little)

2a Increased overjet >3.5 mm but <6 mm with competent lips

2b Reverse overjet >0 mm but ≤1 mm

2c Anterior or posterior crossbite with ≤1 mm discrepancy between retruded contact position and intercuspal position

2d Contact point displacements >1 mm but ≤2 mm

2e Anterior or posterior openbite >1 mm but ≤2 mm

2f Increased overbite ≥3.5 mm without gingival contact

2g Pre-normal or post-normal occlusions with no other anomalies. Includes up to half a unit discrepancy

Grade 3 (borderline need)

3a Increased overjet >3.5 mm but ≤6 mm with incompetent lips

3b Reverse overjet greater than 1 mm but ≤3.5 mm

3c Anterior or posterior crossbites with >1 mm but ≤2 mm discrepancy between the retruded contact position and intercuspal position

3d Displacement of teeth >2 mm but ≤4 mm

3e Lateral or anterior openbite >2 mm but ≤4 mm

3f Increased and incomplete overbite without gingival or palatal trauma

Grade 4 (treatment need)

4a Increased overjet >6 mm but ≤9 mm

4b Reverse overjet >3.5 mm with no masticatory or speech difficulties

4c Anterior or posterior crossbites with >2 mm discrepancy between the retruded contact position and intercuspal position

4d Severe displacements of teeth >4 mm

4e Extreme lateral or anterior open bites >4 mm

4f Increased and complete overbite with gingival or palatal trauma

4h Less extensive hypodontia requiring pre-restorative orthodontics or orthodontic space closure to obviate the need for a prosthesis

4l Posterior lingual crossbite with no functional occlusal contact in one or more buccal segments

4m Reverse overjet >1 mm but <3.5 mm with recorded masticatory and speech difficulties

4t Partially erupted teeth, tipped and impacted against adjacent teeth

4x Existing supernumerary teeth

Grade 5 (treatment required)

5a Increased overjet >9 mm

5h Extensive hypodontia with restorative implications (more than one tooth missing in any quadrant requiring pre-restorative orthodontics

5i Impeded eruption of teeth (apart from 3rd molars) due to crowding, displacement, the presence of supernumerary teeth, retained deciduous teeth, and any pathological cause

5m Reverse overjet >3.5 mm with reported masticatory and speech difficulties

5p Defects of cleft lip and palate

5s Submerged deciduous teeth

Index of Orthodontic Treatment Need (IOTN). AESTHETIC COMPONENT (AC)