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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