Class II div 1 Flashcards
defintion class II div 1
BSI
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
most common form of malocclusion
class II div1
why tx pt who has class II div 1 malocclusion/
2
concerns re aesthetics
concerns re dental health
* prominent incisors at risk of trauma esp if incompetent lips
overjet >9mm
* twice as likely to suffer trauma
* IOTN 5a
overjet >9mm
concerns
2
- twice as likely to suffer trauma
- IOTN 5a
aetiology of class II div1
4
- skeletal pattern - A/P, vertical, transverse
- soft tissues
- dental factors
- habits
A/P skeletal pattern for class II div 1
Usually associated with Class II skeletal pattern
Commonly due to a retrognathic mandible (smaller, set back)
* Maxillary protrusion less common
*Do see with skeletal class 1
Can get inc OJ with class 1 skeletal. Incisors are proclined
Very rarely see with skeletal class 3, but possible
Class 3 incisors proclined in a way that gives them inc overjet *
OJ due to
3
skeletal pattern
tooth inclination
combination of both
if see clinically proclination UI, retroclination LI
think
lower lip trapped behind U= finger suck habit
develop an eye for what is causing incisor relationships
if see clinically proclination UI, retroclination LI
think
lower lip trapped behind U= finger suck habit
develop an eye for what is causing incisor relationships
vertical skeletal pattern for class II div 1
variety
low, high, ave - no rule
often slightly steep plane angle
any associated with inc OJ
transverse skeletal pattern for class II div 1
no particular association with transverse problems
slight narrow maxilla sometimes
any associated with inc OJ
SNA
sella to nasion
A depth of concavity of maxilla
rep maxilla to anterior cranial base
SNB
sella to nasion
B concavity of mandible
represent mandible to anteiror cranial base
ANB
difference between A and B, how much class I or II pt is
MxP/MnP
maxillary plane, Frankfurt plane
* orbitale to porion- should be parallel to floor
compared to mandibular plane
LAFH/TAFH
nasion to anterior nasal spine
anterior nasal spine to menton (base of mandibular symphsis)
should be 55%
soft tissues in class II div 1
Lips often incompetent due to prominence of incisors and/or underlying skeletal pattern
Lower lip trap can be aetiological factor in increased overjet
* Can cause proclination and inc OJ more
* But also side effect of proclination
If lips incompetent then special effort needed to achieve an anterior oral seal
* Mentalis muscle habitual inc to get lower lip in from UI to close with upper lip to achieve ant oral seal
* May posture forwards
* Can assess when in dental chair
achieving an anterior oral seal
3
- 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
dental factors in class II div 1
Increased overjet (incisors proclined or average?)
Overbite varies
* hand in hand with inc or reduced face height
Can see good alignment, crowding or spacing
* Crowding - upper lateral tucked behind Ucentrals, cont to OJ
Molar relationship
* Variable
Habitually parted lips may lead to drying of gingiva and exacerbation of any pre-existing gingivitis
* lead to hyperplastic gingivitis, exposure to air inc, OH poor inc
NNSH
non-nutritional sucking habit
thumb, fingers, blanket, lip, combination
NNSH effect
depends on duration and intensity
occlusal features of NNSH
4
proclination of upper anteriors
retroclinatoin of lower anteriors
localised AOB or incomplete OB
* bilateral or unilateral
narrow upper arch (may see unilateral posterior crossbite)
habit tx principles
3
Stop habit
* Reinforcement
* Removable appliance habit breaker
* Fixed appliance habit breaker
Allow spontaneous improvement
Treat residual malocclusion if required
child wants to stop makes easier
when is it key for habit to be broken
Persisting beyond age of 9 more disruptive to occlusion, reduce chance of getting ideal occlusion with tx
OJ may improve - depends if lower lip a factor, if so unlikely
AOB spontaneous closure possible if habit stopped
Habit stopped before tx – as factor in relapse afert tx
5 management options for class II div1
accept
attemt growth modification
simple tipping of teeth
camouflage
orthognathic surgery
accepting class II div 1
when
warning
Mildly increased overjet
Significant overjet but not unhappy
treatment options be more difficult in the future
* correction when stopped growing more diff – e.g. teeth harder to move and no more growth
Advice re mouthguard
IOTN score low, aesthetic minimal
No great pt concerns
2 modes of attempting growth modification in class II div1
headgear
functional appliance
headgear
growth modification for class II div1
Try and restrain growth of maxilla horizontally and/or vertically
Not commonly used
Hard to know long term effect from evidence currently
Uses back of head as anchorage support, distalise upper molars can try and intrude upper molar
Reduced over bite and AOB
Hard to get 14+ hours wear – not going to wear out, need long time on to make effect
functional appleance
growth modification for class II div1
“utilize, eliminate, or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion”
Used mostly for class II division 1
* Can use for II div 2. Limited use for class III
Posture muscle forwards
Encourage mandibular condyles to grow as condyle extracted out of glenoid fossa
types of functional appliance
removable (pt compliant dependent)
* tooth borne - twin block (most widely used globally)
* soft tissue borne - Frankel
fixed
* Herbst
tooth borne fixed appliances
Twin block (most widely used globally)
* Clasps onto lower teeth
* Blocks hold mand forward in postured position
* Edge to edge more than class I
* Want good retraction to upper arch
Activator/bionator
fixed appliance soft tissue borne
frankel (different types 1, 2, 3 and 4; use FRii for class ii)
soft tissue sulcus shield, aims to posture mandible and expansion of maxilla, effect alveolar growth – likely sim to other devices
fixed functional appliances
herbst
most common fixed functional appliance
* Silver CoCr capping on teeth, connecting rod to hold mandible forward
* More likely to give efficient correction of occlusion
* Prone to break
functional appliance aim
to produce restraint of maxillary growth and encourage mandibular growth
functional appliance success depends on
favourable growth and enthusiastic pt
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
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
dento-alveolar changes due to functional appliances
4
- Distal movement upper dentition
- Mesial movement lower dentition
- Retroclination of upper incisors
- Proclination of lower incisors
when to use a functional?
Should be used during growth
If possible coincide with pubertal growth spurt but?
Options:
* Early use – about 10 years (2 phase tx)
* Later use – late mixed or early permanent dentition (1 phase tx)
3 potential disadv of early functional appliance tx
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 - Can be hard to wear appliance after primary teeth exfoliate, but want to hold tx result until permanent dentition fully erupted
* 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
3 potential adv of early functional appliance tx
Improve appearance earlier (teasing and potential psychological benefit)
Reduce risk of trauma
Often better compliance with appliance wear
ideal candidate for functional appliance has
2
well aligned arches and complele or nearly permanent dentition
Inc OB – good, forward growth rotation of mandible, bodes well for func tx
simple tipping of teeth for class II div 1
limited role in the contemporary treatment of increased overjets
unless
* V mild class II or class I
* Overjet due to proclined and space incisors
* Overbite favourable
* Only then after specialist assessment
e.g. occlusion not far from class I and only OJ needing correct
risk of just simple tipping of teeth class II div 1 tx
2
iatrogenic class II div II created
* possible too class II first place
* no control on degree of OJ reduction
OB increased here
* Contemporary fixed appliances better tx option
URA for simple tipping of upper incisors (OJ reduction)
Aim: please construct a URA to reduce OJ
Active: Roberts retractor 0.5mm HSSW, 0.5mm ID tubing
* Reduce OJ
Retention: Adam’s clasps on 6/6 0.7mm HSSW
Anchorage: good
Stops: mesial to 3/3 0.6mm flattened HSSW
Base plate: Flat anterior bite plane OJ+3mm
* Prop bite open, progressive trim to allow UI retraction
camoflage for class II div1
older - stopped growing 15y+
fixed appliance correct incisor relationship (OJ) no attempt to fix jaw growth
* No growth mod happening, OJ reduced by tipping UI and LI
* Take out upper premolar to make space, retract canine and upper incisors to reduce OJ
* Lower incisors proclined
Not huge change in profile – dento alveolar tx only not skeletal
possible camoflage tx options for class II div1
older pt, no longer growing
- No growth mod happening, OJ reduced by tipping UI and LI
- Take out upper premolar to make space, retract canine and upper incisors to reduce OJ
- Lower incisors proclined
*Can see recession associated with LI, due to non growing limited alveolar bone to maintain coverage of root, causing recession - warn pt *
when is growth complete in females
16-18y
when is growth complete in males
18-20y
orthognathic surgery for class II div 1
carried out when growth complete
severe A/P skeletal discrepancy and/or vertical discrepancy
* cannot correct occlusion with ortho alone
usually improve mandible surgically, sometimes maxilla too
* Surgical advance mandible Class II div I -* sometimes both need moved forward*
* Assess where discrep lies before, and pt concern (largely based)
fixed appliance is always required
at one or more of these times:
* before
* during
* after
tx done here
Inc oJ fixed appliance to align arches
Shows too much upper gingival wants correct
Full unit class II occlusion And inc OJ
* Maxillary impaction – osteomy to reduce amount of show upper incisors and gingiva
* mandible advance to bring forward
After surgery more class I
* Elastics to hold in place
Now class I molar and incisor relationship
Lower face height reduced too as maxilla move up
