| Grade 5 (Extreme/Need treatment) | ||
| 5•i | Impeded eruption of teeth (except for third molars) due to crowding, displacement, the presence of supernumerary teeth, retained deciduous teeth and any pathological cause. | |
| 5•h | Extensive hypodontia with restorative implications (more than 1 tooth missing in any quadrant) requiring pre-restorative orthodontics. | |
| 5•a | Increased overjet greater than 9 mm. | |
| 5•m | Reverse overjet greater than 3.5 mm with reported masticatory and speech difficulties. | |
| 5•p | Defects of cleft lip and palate and other craniofacial anomalies. | |
| 5•s | Submerged deciduous teeth. | |
| Grade 4 (Severe/Need treatment) | ||
| 4•h | Less extensive hypodontia requiring pre-restorative orthodontics or orthodontic space closure to obviate the need for a prosthesis. | |
| 4•a | Increased overjet greater than 6 mm, but less than or equal to 9 mm. | |
| 4•b | Reverse overjet greater than 3.5 mm with no masticatory or speech difficulties. | |
| 4•m | Reverse overjet greater than 1 mm but less than 3.5 mm with recorded masticatory and speech difficulties. | |
| 4•c | Anterior or posterior crossbites with greater than 2 mm discrepancy between retruded contact position and intercuspal position. | |
| 4•l | Posterior lingual crossbite with no functional occlusal contact in one or both buccal segments. | |
| 4•d | Severe contact point displacements greater than 4 mm. | |
| 4•e | Extreme lateral or anterior open bites greater than 4 mm. | |
| 4•f | Increased and complete overbite with gingival or palatal trauma. | |
| 4•t | Partially erupted teeth, tipped and impacted against adjacent teeth. | |
| 4•x | Presence of supernumerary teeth. | |
| Grade 3 (Moderate/Borderline need) | ||
| 3•a | Increased overjet greater than 3.5 mm, but less than or equal to 6 mm with incompetent lips. | |
| 3•b | Reverse overjet greater than 1 mm, but less than or equal to 3.5 mm. | |
| 3•c | Anterior or posterior crossbites with greater than 1 mm, but less than or equal to 2 mm discrepancy between retruded contact position and intercuspal position. | |
| 3•d | Contact point displacements greater than 2 mm, but less than or equal to 4 mm. | |
| 3•e | Lateral or anterior open bite greater than 2 mm, but less than or equal to 4 mm. | |
| 3•f | Deep overbite complete on gingival or palatal tissues, but no trauma. | |
| Grade 2 (Mild/Little Need) | ||
| 2•a | Increased overjet greater than 3.5 mm, but less than or equal to 6 mm with competent lips. | |
| 2•b | Reverse overjet greater than 0 mm but less than or equal to 1 mm. | |
| 2•c | Anterior or posterior crossbite with less than or equal to 1 mm discrepancy between retruded contact position and intercuspal position. | |
| 2•d | Contact point displacements greater than 1 mm but less than or equal to 2 mm. | |
| 2•e | Anterior or posterior open bite greater than 1 mm but less than or equal to 2 mm. | |
| 2•f | Increased overbite greater than or equal to 3.5 mm without gingival contact. | |
| 2•g | Pre- or post-normal occlusions with no other anomalies (includes up to half a unit discrepancy). | |
| Grade 1 (No Need) | ||
| 1• | Extremely minor malocclusions including contact point displacements less than 1 mm. | |