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

Concerns re aesthetics - (upper teeth more at show with lower lip trap)

Concerns re dental health
– Prominent incisors at risk from trauma especially
if incompetent lips
– Overjet >9mm twice as likely to suffer trauma - (will know this by age 11)
– Overjet >9mm, IOTN(dhc) 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 of
both

Question 4

1) what is skeletal pattern (vertical) features?

2) what is features of skeletal pattern transverse?

Answer 4

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

2) No particular association with transverse
problems - (more likely to have a narrow maxilla especially if caused by a digit sucking habit)

Question 5

Answer 5

Question 6

what aren normal values of lateral ceph?

Answer 6

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 7

what is this for

Answer 7

measuring lower face height

Question 8

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

2) how to achieve an anterior oral seal?

Answer 8

Lips often incompetent due to
prominence of incisors and/or
underlying skeletal pattern

Lower lip trap can be aetiological
factor in increased overjet

If lips incompetent then special
effort needed to achieve an
anterior oral seal

2)Lip to lip seal by activity of
circum-oral musculature
– Mandible postured to
allow lips to meet
or
– Lower lip drawn up
behind upper incisors
– Tongue placed forwards
between incisors to lower
lip
or
– Combination of these

Question 9

explain dental factors of class II div 1

Answer 9

Increased overjet (incisors proclined or average?)

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 10

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

Answer 10

nnsh - non nutritive sucking habits

thumb
fingers
blanket
lip
combination

Question 11

what are occlusal features of sucking habit?

Answer 11

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 12

what are principles of habit treatment?

Answer 12

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 13

what are management options of class II div 1?

Answer 13

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 14

when will you accept as an option?

Answer 14

Mildly increased overjet
Significant overjet but not unhappy

Advice re mouthguard

Question 15

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

what age does it become more difficult?

Answer 15

over ages of 11,12,13 becomes more difficult

HEADGEAR - (not as common now)
– Try and restrain growth
of the maxilla
horizontally and/or
vertically

FUNCTIONAL
APPLIANCE
- “Functional appliances utilize, eliminate, or
guide the forces of muscle function, tooth
eruption and growth to correct a
malocclusion”
- Can use for II div 2
– Limited use for class III

works by mandible posture downwards

Question 16

what are types of functional appliance?

Answer 16

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 17

what is this

Answer 17

fixed herbst functional appliance

Question 18

what is this?

Answer 18

twin-block appliance

Question 19

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

Answer 19

Aim to produce restraint of
maxillary growth &
encourage mandibular
growth

Success depends on
favourable growth &
enthusiastic patient

Question 20

what is therapeutic effect of functional appliances?

Answer 20

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

Minor degree of skeletal changes
* RCT’s indicate that degree of
maxillary restraint and mandibular
growth is usually small (1-2mm)
* Significant variation in response

Question 21

When to use a functional
appliance?

Answer 21

Should be used during growth
If possible coincide with pubertal growth
spurt but ?

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 22

1) what are potential disadvantages of early treatment?

2) potential benefits?

Answer 22

1) – Early skeletal effects from functional appliance or
headgear therapy not maintained in long term
– Overall treatment time increased, 2 phase treatment
* Early functional appliance plus retention
* Fixed appliances in early permanent dentition
– Research shows little if any difference in results between
those treated early and those who waited until permanent
dentition

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

Question 23

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

2) why not favourable type of tx?

Answer 23

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 24

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

Answer 24

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 25

explain orthognathic surgery?

Answer 25

• 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