1. Index of Orthodontic Treatment Need (IOTN)

Question 1

What are the four occlusal features of a digit sucking habit ?

Answer 1

Proclination of upper anteriors.
Retroclination of lower anteriors.
Localised AOB or incomplete OB.
Narrow upper arch +/- unilateral crossbite.

Question 2

What are the three ways which anteroposterior skeletal pattern can be assessed ?

Answer 2

Visual assessment.
Palpate skeletal bases.
Lateral cephalometry.

Question 3

AP skeletal pattern - define skeletal class I.

Answer 3

Mandible 2-3mm behind maxilla.

Question 4

AP skeletal pattern - define skeletal class II.

Answer 4

Mandible >2-3mm behind maxilla.

Question 5

AP skeletal pattern - define skeletal class III.

Answer 5

Mandible in front of maxilla.

Question 6

How is the vertical skeletal pattern assessed ?

Answer 6

Assess Frankfort-mandibular plane angles (FMPA).
Assess vertical facial proportions.
Lateral cephalometry.

Question 7

The Frankfort plane is measured between what two points ?

Answer 7

Porion to orbitale.

Question 8

The mandibular plane is measured between what two points ?

Answer 8

Gonion to menton.

Question 9

What two points is UAFH measured between ?

Answer 9

Glabella to subnasale.

Question 10

What two points is LAFH measured between ?

Answer 10

Subnasale to menton.

Question 11

What two points is TAFH measured between ?

Answer 11

Glabella to menton.

Question 12

Define competent lips.

Answer 12

Meet together at rest without any muscular activity.

Question 13

What is the average naso-labial angle ?

Answer 13

100 degrees.