Index of Orthodontic Treatment Need (IOTN)

Question 1

What is the score for excessive hypodontia with restorative implications (ie more than one tooth in any quadrant)?

Answer 1

5h

Question 2

What is 5i

Answer 2

impeded eruption of teeth (except of 3rd molars)

Question 3

What is 5a?

Answer 3

increased overjet of more than >9mm

Question 4

What is the score for reverse overjet of >3.5mm with reported masticatory and/or speech problems?

Answer 4

5m

Question 5

What is 5p

Answer 5

defects of cleft lip and palate/ other craniofacial abnormality

Question 6

what is the score for submerged primary teeth?

Answer 6

5s

Question 7

what is 4h

Answer 7

less extensive hypodontia requiring restorative input or orthodontic space closure

Question 8

what is the score for an increased overjet of >6mm ≤ 9mm

Answer 8

4a

Question 9

What is 4b in IOTN?

Answer 9

reverse overjet >4.5mm with no reported masticatory or speech problems

Question 10

What score would you assign for anterior or posterior crossbites with >2mm displacement

Answer 10

4c

Question 11

What score would you assign for a reverse overjet of >1mm ≤ 3.5mm with recorded masticatory and speech difficulties?

Answer 11

4m

Question 12

What is 4I

Answer 12

posterior lingual crossbite (scissor bites) with no occlusal contact in one or both buccal segments

Question 13

What is 4d?

Answer 13

contact point displacement of >4mm

Question 14

What score would you assign extreme lateral/AOB of >4mm?

Answer 14

4e

Question 15

What is 4f in IOTN

Answer 15

Increased and complete overbite with palatal trauma

Question 16

What is 4t in IOTN

Answer 16

partially erupted teeth impacted against neighbouring tooth

Question 17

What score do you give supernumerary teeth?

Answer 17

4x

Question 18

What is 3a in IOTN?

Answer 18

Increased overjet >3.5mm <6mm with incompetent lips

Question 19

what is 3b in IOTN

Answer 19

reverse overjet of >1mm < 3.5mm

Question 20

What score would you give anterior or posterior crossbites with >1mm ≤ 2mm discrepancy between CR and CO?

Answer 20

3c

Question 21

What is 3d in IOTN?

Answer 21

contact point displacement of >2mm ≤ 4mm

Question 22

What score would you give lateral/AOB of >2mm ≤ 4mm?

Answer 22

3e

Question 23

What is 3f in IOTN?

Answer 23

deep overbite complete on gingival or palatal tissue without trauma

Question 24

What is 2a in IOTN?

Answer 24

increased overjet of >3.5mm <6mm but with competent lips

Question 25

What score would you give reverse overjet >0mm <1mm

Answer 25

2b

Question 26

What score would you give anterior or posterior crossbite with ≤ 1mm discrepancy between CO and CR?

Answer 26

2c

Question 27

What is 2d in IOTN?

Answer 27

contact point displacement >1mm ≤ 2mm

Question 28

What is 2e in IOTN?

Answer 28

lateral/anterior open bite of >1mm ≤ 2mm

Question 29

What is 2f in IOTN?

Answer 29

increased overbite of 3.5mm or more without gingival contact

Question 30

What is 2g in IOTN?

Answer 30

pre normal or post normal occlusions with no other anomalies ( < 1/2 unit discrepancies)

Question 31

What is 1 in IOTN?

Answer 31

extremely minor malocclusions including <1mm contact point discrepancies