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?
- aesthetics
*show more upper teeth - trauma
*prominent incisors if incompetent lips
*overjet >9mm (iotnDHC 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 ofboth
why does it tend to be class II skeletal
Commonly due to a retrognathic mandible
– Maxillary protrusion less common
1) what is skeletal pattern (vertical) features?
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)
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?
- incompetent lips
*due prominent incisors
*need to achieve oral seal - Lower lip trap - cause of overjet
2) how to achieve an anterior oral seal?
- mandible postured allow lips meet
or - lower lip drawn up behind upper incisors and tongue placed forwards between incisors to lower lip
or - combo
explain dental factors of class II div 1
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
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
*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
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
*restraint of maxillary growth
*encourage mandibular
growth
Success depends on favourable growth & enthusiastic patient
what is 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
1) what are potential disadvantages of early treatment for class II div 1?
- overally tx time increased - 2 phase
*early functional then fixed in early permanent
When to use a functional
appliance?
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)
2) potential benefits of early tx to class 2 div 1?
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
what do functional appliances do?
“Functional appliances utilize, eliminate, or guide the forces of muscle function, tooth eruption and growth to correct a
malocclusion”
