Class II div 1 Flashcards
what is definition of Class II div 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
why treat Class II div 1?
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
1) what is skeletal patter feature of class II div 1?
2) what is overjet due to?
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
1) what is skeletal pattern (vertical) features?
2) what is features of skeletal pattern transverse?
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)
what aren normal values of lateral ceph?
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%
what is this for
measuring lower face height
1) explain soft tissue features of class II div 1?
2) how to achieve an anterior oral seal?
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
explain dental factors of class II div 1
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
what are types of sucking habits and what does nnsh mean?
nnsh - non nutritive sucking habits
thumb
fingers
blanket
lip
combination
what are occlusal features of sucking habit?
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
what are principles of habit treatment?
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
what are management options of class II div 1?
- Accept
- Attempt growth modification - first choice
- Simple tipping of teeth - work for slightly older patients
- Camouflage - work for older pts where removable appliance won’t work
- Orthognathic surgery
when will you accept as an option?
Mildly increased overjet
Significant overjet but not unhappy
Advice re mouthguard
how do you attempt growth modification? and how do they work?
what age does it become more difficult?
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
what are types of functional appliance?
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
what is this
fixed herbst functional appliance
what is this?
twin-block appliance
what is aim of functional appliance and what does success depend on?
Aim to produce restraint of
maxillary growth &
encourage mandibular
growth
Success depends on
favourable growth &
enthusiastic patient
what is therapeutic effect of functional appliances?
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
When to use a functional
appliance?
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)
1) what are potential disadvantages of early treatment?
2) potential benefits?
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
1) explain simple tipping of teeth as management of class II div 1?
2) why not favourable type of tx?
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
what is process of retroclining anterior teeth for ura for class II div 1?
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
explain orthognathic surgery?
- 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
