Quick reference guide to Orthodontic assessment and referral - Scott JK and Atack NE - Stage guidance

Oct 12, 2026

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Quick reference guidance for orthodontic assessment and referral across deciduous, mixed, and permanent dentition stages. Covers normal development indicators such as eruption patterns, spacing, and canines palpability, alongside referral indications including severe skeletal discrepancies, delayed development, missing or supernumerary teeth, radiotherapy/chemotherapy history, anomalies and crossbites. For permanent dentition, clarifies IOTN thresholds for NHS referral versus private orthodontic provider referral, with notes for borderline Grade 3 cases and adult eligibility for NHS treatment.

LanguageEnglish

CategoryLetters

FormatPDF

Pages2

Reading Time1 min

AccessFree to download

Eruption Patterns

Index of Orthodontic Treatment Need (DHC)

Stage guidance

Deciduous Dentition

Mixed Dentition

Permanent Dentition

References

| Quick reference guide to Orthodontic assessment and treatment need | | | --- | --- | | Eruption Patterns | Index of Orthodontic Treatment Need© (DHC)2
Reproduced by permission of Oxford University Press | | | For use in permanent dentition only
Grade 3 (Borderline need) For NHS treatment also need aesthetic >6
3a. Increased overjet 3.5mm ≤ 6mm with incompetent lips 3b. Reverse overjet 1mm ≤ 3.5mm
3c. Anterior or posterior crossbites with 1mm ≤ 2mm discrepancy between
retruded contact position and intercuspal position 3d. Contact point displacements 2mm ≤ 4mm 3e. Lateral or anterior open bite 2mm ≤ 4mm
3f. Deep overbite complete to gingival or palatal tissues but no trauma
Grade 4 (Need treatment)
4h. Less extensive hypodontia requiring pre-restorative orthodontics or orthodontic space closure to obviate the need for a prosthesis.
4a. Increased overjet 6mm ≤ 9mm
4b. Reverse overjet >3 .5mm with no masticatory or speech difficulties 4m. Reverse overjet 1mm < 3.5mm with recorded masticatory and 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 >4mm 4e. Extreme lateral or anterior open bites >6mm
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
Grade 5 (Need treatment)
5i. Impeded eruption of teeth (except for third molars) due to crowding, displacement, the presence of supernumerary teeth, retained deciduous teeth or any pathological cause
5h. Extensive hypodontia with restorative implications (>1 tooth missing in any quadrant) requiring pre-restorative orthodontics
5a. Increased overjet >9mm
5m. Reverse overjet >3 .5mm with reported masticatory and speech difficulties 5p. Defects of cleft lip and palate and other craniofacial anomalies
5s. Submerged deciduous teeth | | Average Eruption Dates 1 | | |

References
1. Scott JH & Symons NBB, 1990, Introduction to Dental Anatomy 9th ed. Churchill Livingstone.
2. Brook PH & Shaw WC (1989) . The development of an index of orthodontic treatment priority. Eur J Orthod 11 : 309-320. | | | Quick reference guide to Orthodontic assessment and referral
Scott JK and Atack NE, 2015 | | | | --- | --- | --- | | | | | | Stage | Normal Development | Indications for referral | | Deciduous
Dentition | • Normal eruption pattern (see overleaf)
• Spacing is normal (primate spaces)
• Encourage cessation of thumb/finger/dummy sucking before 5 years old | • Severe skeletal discrepancies
• Severely delayed dental development
• Missing/supplemental teeth
• History of head and neck radiotherapy +/ -chemotherapy
• Advice for balancing/compensating extractions | | Mixed Dentition | • Normal eruption pattern (see overleaf)
• Contralateral teeth should erupt within 6/12
• Midline (median) diastema normal
• Maxillary canines palpable at 10 years old | • Severe skeletal patterns where early treatment may be appropriate e.g. developing class II/III
• Dental anomalies e.g. double teeth, dens-in-dente, talon cusps
• Developmentally missing permanent teeth
• Supernumerary teeth
• Teeth in unfavourable positions e.g. canines
• Impacted first permanent molars
• Infraoccluded teeth
• Crossbites
• Extraction advice where severe crowding evident or first molars have poor prognosis
• Advice following trauma to permanent teeth | | Permanent Dentition | • Skeletal base acceptable
• All permanent teeth present
• Class I incisors
• Class I molar relationship
• Average overjet 2-4mm
• Average overbite (1/3rd – ½ lower inc coverage)
• Well aligned arches | • Clear-cut IOTN eligible for NHS treatment?
YES (IOTN

FAQs

What are the referral indications in deciduous dentition?

Referral is indicated for severe skeletal discrepancies, severely delayed dental development, missing or supplemental teeth, history of head and neck radiotherapy +/- chemotherapy, and advice for balancing or compensating extractions.

What should be checked for mixed dentition before deciding on referral?

Assess whether eruption is within expected timing, spacing is normal, midline diastema is normal, and maxillary canines are palpable at about 10 years. Referral is considered for severe developing skeletal patterns, dental anomalies, developmentally missing permanent teeth, supernumerary teeth, unfavourable tooth positions, impacted first permanent molars, infraocclusion, crossbites, extraction advice in severe crowding, and post-trauma management.

How are NHS referral decisions made for permanent dentition?

Determine if the case is clear-cut IOTN eligible for NHS treatment: YES when IOTN 3/6 and above, NO when below. Borderline cases (Grade 3 below 3/6) may be referred for NHS assessment due to difficulty in evaluation, and adults may qualify for NHS treatment if they need complex multidisciplinary care.

Oct 12, 2026

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