Orthodontic Classifications

Question 1

What does Angle’s classification define ?

Answer 1

First permanent molar relationship.

Question 2

What does BSI classification define ?

Answer 2

Incisor relationship.

Question 3

Define neutrocclusion i.e. Class I molar relationship.

Answer 3

Mesiobuccal cusp of upper first permanent molar occludes with the buccal groove of lower first permanent molar.

Question 4

Define post-normal or distocclusion i.e. Class II molar relationship.

Answer 4

Mesiobuccal cusp of upper first permanent molar occludes anterior to the buccal groove of lower first permanent molar.

Question 5

Define pre-normal or mesiocclusion i.e. Class III molar relationship.

Answer 5

Mesiobuccal cusp of upper first permanent molar occludes posterior to the buccal groove of lower first permanent molar.

Question 6

Define Class I incisor relationship (BSI).

Answer 6

Incisal edges of lower anterior teeth occlude with or below the cingulum plateau of upper incisors.

Question 7

Define Class II Div 1 incisor relationship (BSI).

Answer 7

Incisal edges of lower anterior teeth occlude posterior to the cingulum plateau of upper incisors with upper central incisors proclined or of average inclination and there is a increased OJ.

Question 8

Define Class II Div 2 incisor relationship (BSI).

Answer 8

Incisal edges of lower anterior teeth occlude posterior to cingulum plateau of upper incisors with upper central incisors retroclined with minimal OJ (can be increased).

Question 9

Define Class III incisor relationship (BSI).

Answer 9

Incisal edges of lower anterior teeth occlude anterior to cingulum plateau of upper incisors with a reduced or reverse OJ.

Question 10

What is IOTN classification ? Why was it developed ?

Answer 10

Index of Orthodontic Treatment Need.
Developed to identify malocclusions which would most benefit from orthodontic treatment from health and appearance components.

Question 11

What are the two components of IOTN classification ?

Answer 11

Dental health component and aesthetic component.

Question 12

What does the dental health component of the IOTN classification do ?

Answer 12

Grades dentition in relation to treatment need based on the single worst feature of malocclusion. Grades severity of occlusal characteristics that could increase morbidity of dentition or impair function.

Question 13

What acronym can be used to assess occlusal features (dental health component of IOTN classification) ?

Answer 13

MOCDO

Question 14

What does MOCDO stand for (dental health component of IOTN classification) ?

Answer 14

Missing teeth.
Overjet.
Crossbite.
Displacement of contact points.
Overbite.

Question 15

Define IOTN Grade 5.a ?

Answer 15

OJ >9mm.

Question 16

Define IOTN Grade 5.i ?

Answer 16

Impeded eruption of teeth (except third molars) owing to crowding, displacement, supernumerary teeth, retained primary teeth and pathological cause.

Question 17

Define IOTN Grade 4.a ?

Answer 17

OJ >6mm but <9mm.