IOTN Guide

Nasir Al-Hamlan BDS, MPH, MSc, FDS RCSEd, FDS RCSEd, MOrth RCSEd, FICD
Consultant and Assistant Professor, Orthodontics
King Saud bin Abdulaziz University for Health Sciences
Riyadh, Saudi Arabia
@nhalhamlan
@saudibraces
nasiralhamlan
@nasiralhamlan
Index of Orthodontic Treatment Need (IOTN)
(Brook and Shaw, 1989)

Index of Orthodontic Treatment Need (IOTN) (Brook and
Shaw, 1989)

- Developed to rank malocclusion in terms of various occlusal
traits to:
- Dental health
- Aesthetic impairment,
- Fulfill general requirement of indices
- The components of IOTN
1- Dental Health Component (DHC)
2- Aesthetic Component (AC)
Index of Orthodontic Treatment Need (IOTN) (Brook and Shaw, 1989)

Advantages of IOTN
- Involved both patient and clinician
- Quick and simple
- Can be used directly on patients or SM
- Reliable
- IOTN has been validated by a panel of 74 dentists (Shaw et al., 1991)
- Operators scores improves overtime (Cooper et al., 2000)

It records only the worse occlusal feature:
- Hierarchical scale:
1- Missing teeth (including developmental absence, ectopic and impacted
teeth)
2- OJ (including reverse OJ)
3- Crossbites
4- Displacement of contact points
5- Overbites (including openbites)
“MOCDO”
Dental Health Component (DHC)

DHC has 5 categories (with multiple sub divisions) :
Grade 1-2 = No need for treatment
Grade 3 = Moderate/borderline need for treatment
Grade 4-5 = Need treatment

GRADE 1 (No Need)
1. Extremely mild malocclusions including contact point
displacements < 1 mm

GRADE 2 (Little Need)
2.a Increased OJ > 3.5 mm ≤ 6 mm with competent lips
2.b Reverse OJ > 0 mm ≤1 mm
2.c Anterior/posterior crossbite ≤ 1 mm discrepancy RCP-ICP
2.d Contact point displacements > 1 mm ≤ 2 mm
2.e Anterior/posterior openbite > 1 mm ≤ 2 mm
2.f Increased OB ≥ 3.5 mm without gingival contact
2.g Pre-normal/post-normal occlusions with no other anomalies,
(includes up to ½ unit discrepancy)

GRADE 3 (Moderate Need)
3.a Increased OJ > 3.5 mm but ≤ 6 mm with incompetent lips
3.b Reverse OJ > 1 mm but ≤ 3.5 mm
3.c Anterior/posterior crossbites > 1 mm ≤ 2mm discrepancy between RCP- ICP
3.d Contact point displacements > 2 mm ≤ 4 mm
3.e Lateral /anterior open bites > 2 mm ≤ 4 mm
3.f Deep OB complete to gingival or palatal tissues but non traumatic

GRADE 4 (Great Need)
4.h Less extensive hypodontia requiring prerestorative ortho/or ortho
space closure to obviate need for prosthesis
4.a Increased OJ > 6 mm ≤ 9 mm
4.b Reverse OJ > 3.5 mm but no masticatory/speech problems
4.m Reverse OJ > 1 mm < 3.5 mm with masticatory/speech problems
4.c Anterior/posterior crossbites > 2 mm discrepancy between RCP – ICP

GRADE 4 (Great Need)
4.l Posterior lingual crossbites with no functional occlusal contact in one
or both buccal segments
4.d Severe contact point displacements > 4 mm
4.e Extreme lateral or anterior openbites > 4 mm
4.f Increased/complete OB with gingival/palatal trauma
4.t Partially erupted teeth, tipped/impacted against adjacent teeth
4.x Supernumerary teeth

GRADE 5 (Very Great Need)
5.i Impeded eruption of teeth (except for third molars) due to crowding,
displacement, supernumerary teeth, retained deciduous teeth and pathology.
5.h Extensive hypodontia with restorative implications (more than 1 tooth
missing in any quadrant) requiring prerestorative orthodontics
5.a Increased OJ > 9 mm
5.m Reverse OJ > 3.5 mm with reported masticatory/speech problems
5.p Cleft lip/palate and other craniofacial anomalies
5.s Submerged deciduous teeth (2 cusps visible or severe tipping adjacent teeth)

Ruler

• 1- attractive ! 10- least attractive,
• Grading:
Grades 1 – 3 = No/slight need for treatment
Grades 5 – 7 = Moderate/borderline need for treatment
Grades 8 – 10 = Need for treatment
• High levels of agreement found between patients, parents
and orthodontists (Evans and Shaw, 1987),
• No account taken of dentition within facial appearance or
direct psychological indexing.
Aesthetic Component (AC)

APPENDIX

APPENDIX OF IOTN DHC
BUCCAL OCCLUSION
- Full unit I, II or III relationship are not recording.
CROSSBITE
. Anterior 1-3 incisors are in lingual occlusion
. Posterior cusp-cusp or in full crossbite
CROWDING
- If space between two teeth next to an unerupted tooth is ≤4 mm,
then this tooth is regarded as being impacted.

CONTACT POINT DISPLACEMENT
- Measured between anatomical contact points when teeth deviate from
the line of the arch
- NOTE displacements between deciduous and permanent teeth are NOT
recorded
IMPEDED ERUPTION
- Tooth unerupted due to close contact of adjacent teeth then DHC = 5.i
- Tooth not fully erupted to the occlusal plane but has tipped against its
adjacent tooth DHC = 4.t

OVERJET
- Most prominent incisor.
- Reverse OJ recorded when FOUR incisors are in lingual occlusion
ROTATION OF TEETH
- NOTE displacements between contact points of rotated teeth are NOT
recorded if they are in the line of the arch
SPACING
- NOT recording, Unless spacing associated with teeth deviating from
the line

SUBMERGING DECIDUOUS TEETH
- NOT recorded unless only two cusps visible and/or the adjacent
teeth are severely tipped towards each other.
PATH OF CLOSURE
- Discrepancies between ICP and RCP are recorded as with crossbites.
OPENBITES
- Measure GREATEST HEIGHT

- Patient can be asked to assess; “Here is a set of
t e n p h o t o g r a p h s s h o w i n g d e n t a l
attractiveness. Number 1 is the most and 10
the least attractive arrangement of teeth.
Where would you put your teeth on this scale?”

IOTN Guide

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IOTN Guide