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Index of Orthodontic Treatment

Need modified for use inEpidemiological Surveys :

Modified IOTN

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Written byDonald Burden and Cynthia Pine

 with assistance

from the BASCD Working Party on Orthodontics

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Modified IOTN consists of two

components:

1. Aesthetic Component

2. Dental Health Component

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Aesthetic Component

Grades 1-7 No Definite Need for treatment

Grades 8-10 Definite Need for treatment

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Recording the Aesthetic Component

•Ask subject to close on their back teeth•Retract lips•Grade the dental attractiveness of the anterior teeth

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Recording the Aesthetic Component

•The grade awarded is for overall dental attractiveness rather than specific morphological similarity to the photographs•First impressions are usually correct•Main aim is to differentiate those at 8 - 10

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Dental Health Component

IOTN has been simplified to twocategories: Definite Need for Treatment No Definite Need for Treatment

The subject is examined for specific conditions and if one is found, a Definite Need for Treatment is recorded and no further conditions are sought.

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Recording the DHC

Examine each subject for:• Missing teeth• Overjets• Crossbites• Displacement of contact points• Overbites = MOCDO

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Recording the DHC

• Examine the subject using the ‘MOCDO’ scale

• As soon as a definite treatment need threshold is reached, then the examination is stopped

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‘MOCDO’

• Missing teeth • Overjets • Crossbites• Displacement of contact points• Overbites

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Missing Teeth (teeth not visible)

• Congenital absence/traumatic loss • Ectopic teeth• Impacted teeth

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Missing Teeth

• Palatally ectopic canines

• Is the canine palpable in the buccal sulcus?

• If not, it is ectopic = Need for Treatment

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Missing Teeth

• IMPACTED if 4mm or less space is available between adjacent teeth

• Impacted = Need for Treatment

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Missing Teeth

• (Congenital absence/traumatic loss)

• In your opinion, is orthodontic treatment required to open or close the space?

• If yes = Need for Treatment

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‘MOCDO’

• Missing teeth• Overjets • Crossbites• Displacement of contact points• Overbites

Original Slide No.15

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Measuring Overjets

Increased overjets (Class II) and reverse overjets (Class III) are measured using the metal ruler

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Positive overjets

Second line (red) – 6mm

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Measuring Overjets

• Measure to the labial aspect of the most prominent incisor

• Only record Need for Treatment if the

overjet extends beyond the 6mm line

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Measuring Reverse Overjets

• All four incisors must be in lingual occlusion

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Measuring Reverse Overjets

• If the reverse overjet falls exactly on the 4mm (white line) record in the Definite Need for Treatment category

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First line (white) – 4mm

CrowdingReverse overjetsOpen bites

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‘MOCDO’

• Missing teeth• Overjets • Crossbites• Displacement of contact points• Overbites

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Crossbites

• Can be anterior or posterior, but mostly posterior.

• Check for displacement on closure.• If displacement on closure = Need for

Treatment

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‘MOCDO’

• Missing teeth• Overjets • Crossbites• Displacement of contact points

(crowding)• Overbites

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Crowding

• Only applies to crowding between permanent teeth

• Measure between the contact points of the two most crowded teeth

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First line (white) – 4mm

CrowdingReverse overjetsOpen bites

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‘MOCDO’

• Missing teeth• Overjets • Crossbites• Displacement of contact points• Overbites

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Overbite

• Deep overbite

• Open bite

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Deep Overbite

• Deep overbite causing gingival or palatal traumatic injury

= Definite Need for Treatment

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Other Points of the Modified IOTN

• Generalised spacing is not recorded in the Dental Health Component

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