Class II div 1

Question 1

what is definition of Class II div 1

Answer 1

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
There is an increased overjet
The upper central incisors are proclined or of average inclination

Question 2

why treat Class II div 1?

Answer 2

• aesthetics
  *show more upper teeth
• trauma
  *prominent incisors if incompetent lips
  *overjet >9mm (iotnDHC 5a)

Question 3

1) what is skeletal patter feature of class II div 1?

2) what is overjet due to?

Answer 3

1) Usually associated with Class II skeletal pattern

Commonly due to a retrognathic mandible
– Maxillary protrusion less common

Do see with skeletal class 1 - with retroclined lower incisors and proclined upper incisors

Very rarely see with skeletal class 3, but possible

2) skeletal pattern
tooth inclination
Combination ofboth

Question 4

why does it tend to be class II skeletal

Answer 4

Commonly due to a retrognathic mandible
– Maxillary protrusion less common

Question 5

1) what is skeletal pattern (vertical) features?

Answer 5

1) Found in association with a range of vertical
skeletal patterns - (FMPA) (if increased more likely for reduced overbite or AOB)

(more likely to have a narrow maxilla especially if caused by a digit sucking habit)

Question 6

Answer 6

Question 7

what aren normal values of lateral ceph?

Answer 7

SNA = 81 +/- 3
SNB = 78 +/- 3
ANB = 3 +/- 2

MxP/MnP = 27 +/- 4

UI/MxP = 109 +/- 6
LI/MnP = 93 +/- 6 - these give indication of how these teeth can be moved

LAFH/TAFH = 55%

Question 8

what is this for

Answer 8

measuring lower face height

Question 9

1) explain soft tissue features of class II div 1?

Answer 9

• incompetent lips
  *due prominent incisors
  *need to achieve oral seal
• Lower lip trap - cause of overjet

Question 10

2) how to achieve an anterior oral seal?

Answer 10

• mandible postured allow lips meet
  or
• lower lip drawn up behind upper incisors and tongue placed forwards between incisors to lower lip
  or
• combo

Question 11

explain dental factors of class II div 1

Answer 11

Increased overjet

Overbite varies

Can see good alignment, crowding or spacing - (displacement of upper incisor labially induced with overjet)

Molar relationship - (could be class 1 if lose ‘e’s early)

Habitually parted lips may lead to drying of gingiva and
exacerbation of any pre-existing gingivitis

Question 12

what are types of sucking habits and what does nnsh mean?

Answer 12

nnsh - non nutritive sucking habits

thumb
fingers
blanket
lip
combination

Question 13

what are occlusal features of sucking habit?

Answer 13

Proclination of upper anteriors
Retroclination of lower anteriors
Localised AOB or incomplete OB
Narrow upper arch (may see unilateral (or possibly bilateral) posterior
crossbite)
could cause increase in vertical dimension as upper molars could overerupt and cause AOB

Question 14

what are principles of habit treatment?

Answer 14

Stop habit
– Reinforcement
– Removable appliance habit breaker
– Fixed appliance habit breaker - (last line) (palatal arch with gold ? and wire at front)

Allow spontaneous improvement - (6 months - 1 year)

Treat residual malocclusion if required

Question 15

what are management options of class II div 1?

Answer 15

1. Accept
2. Attempt growth modification - first choice
3. Simple tipping of teeth - work for slightly older patients
4. Camouflage - work for older pts where removable appliance won’t work
5. Orthognathic surgery

Question 16

when will you accept as an option?

Answer 16

Mildly increased overjet
Significant overjet but not unhappy

Advice re mouthguard

Question 17

how do you attempt growth modification? and how do they work?

what age does it become more difficult?

Answer 17

over ages of 11,12,13 becomes more difficult

• headgear
  *restrain growth maxilla horizontally and/or vertically
• functional appliance
• used mostly for class II div 1
  *can use for class II div 2
  *limited for class III

Question 18

what are types of functional appliance?

Answer 18

Removable
– Tooth-borne
* Twin-block - (most used clip onto teeth with adams clasp)
* Activator/bionator
– Soft tissue borne
* Frankel (FR II) - (not as used in this country)

• Fixed
  – Herbst

Question 19

what is this

Answer 19

fixed herbst functional appliance

Question 20

what is this?

Answer 20

twin-block appliance

Question 21

what is aim of functional appliance and what does success depend on?

Answer 21

Aim
*restraint of maxillary growth
*encourage mandibular
growth

Success depends on favourable growth & enthusiastic patient

Question 22

what is effect of functional appliances?

Answer 22

Mostly dento-alveolar changes
* Distal movement upper dentition
* Mesial movement lower dentition
* Retroclination of upper incisors
* Proclination of lower incisors
maybe a little bit of mandibular growth also

Question 23

1) what are potential disadvantages of early treatment for class II div 1?

Answer 23

• overally tx time increased - 2 phase
  *early functional then fixed in early permanent

Question 24

When to use a functional
appliance?

Answer 24

Should be used during growth

Options:
– Early use – about 10 years old (2 phase trt.)
– Later use – late mixed or early permanent
dentition (1 phase treatment) - (12 or 13 years)
- ideally use functional during period of maximal growth
* females - 11-13 years
* males - 13 - 15 years

(outcome determined by how often they use it)

Question 25

2) potential benefits of early tx to class 2 div 1?

Answer 25

2) - Improve appearance earlier (teasing & potential
psychological benefit)
– Reduce risk of trauma
– Often better compliance with appliance wear

Question 26

1) explain simple tipping of teeth as management of class II div 1?

2) why not favourable type of tx?

Answer 26

1) Simple URA’s have a limited role in the
contemporary treatment of increased overjets

Unless
– V. mild Class II or Class I
– Overjet due to proclined and spaced incisors
– Overbite favourable
– Only then after a specialist assessment

2) remove 4’s then use URA creates another type of malocclusion

Question 27

what is process of retroclining anterior teeth for ura for class II div 1?

Answer 27

Active: Roberts retractor
0.5mm in tubing
* Retention: Adams cribs 6/6
0.7mm HSSW
* ?Anchorage: Stops mesial to
3/3?
* Baseplate: Flat anterior
biteplane

Question 28

explain orthognathic surgery?

Answer 28

• Carried out when growth is complete
• Skeletal discrepancy is severe in A/P & or
  vertical direction
• Usually involves mandibular surgery, but may
  also involve maxillary surgery
• Fixed appliances required
  – Before surgery
  – During surgery
  – After surgery

Question 29

what do functional appliances do?

Answer 29

“Functional appliances utilize, eliminate, or guide the forces of muscle function, tooth eruption and growth to correct a
malocclusion”