IOTN Grade 4 (Great)

 

This grade indicates a severe need for treatment and can be classified as follows:

4h Less extensive hypodontia requiring pre-restorative orthodontics or orthodontic space closure to obviate the need for a prosthesis.
4a Increased overjet greater than 6mm but less than or equal to 9mm.
4b Reverse overjet greater than 3.5mm with no masticatory or speech difficulties.
4m Reverse overjet greater than 1mm but less than 3.5mm with recorded masticatory or speech difficulties.
4c Anterior or posterior crossbites with greater than 2mm discrepancy between retruded contact position and intercuspal position.
4l Posterior lingual crossbite with no functional occlusal contact in one or both buccal segments.
4d Severe contact point displacements greater than 4mm.
4e Extreme lateral or anterior open bites greater than 4mm.
4f Increased and complete overbite with gingival or palatal trauma.
4t Partially erupted teeth, tipped and impacted against adjacent teeth.
4x Presence of supernumerary teeth.