class II div 2 Flashcards
definition(BSI)
The lower incisor occludes posterior to the cingulum plateau of the upper incisor (class 2)
The upper incisors are retroclined
The overjet is reduced but can also be increased
incidence of class II div2
5-18%
4 aetiological categories for class II div 2
skeletal
soft tissue
dental
pathology
AP skeletal pattern for class II div 2
Usually associated with a mid or moderate Sk2 base (point A more anterior to B (greater than 2-3mm), retrognathic and retrogenic)
Can also be Sk1 or Sk3
**incisor classification + skeletal relationship don’t always match*
vertical skeletal pattern for class II div 2
Typically reduced
* Reduced FMPA (meet after occiput, more parallel) and LAFH (<50%)
Often associated with a forward rotational pattern of growth of the mandible
Prominent chin - “progenia”
* Lack of bony chin, but large soft tissue flesh chin
incisor classification and skeletal relationship don’t always match
soft tissue pattern for class II div 2
High resting lower lip line (higher than crowns UI)
* Secondary to lower face height
* Retrocline upper incisors
Marked labio-mental fold (elastic band over LI causing them to retrocline)
High masseteric forces
* Orthodontic space closure problems
Upper 2’s shorter clinical crown so escape the effect of the lower lip
* Trap lower lip – cause flare forward and mesial rotate/proclination
describe the malocclusions here
Mild-mod Sk2, reduced FMPA
BSI class 2 div 2
Flaring and rotations upper 2s
Reduced OJ on centrals, inc on laterals
Shortened arch usually with retroclination UI, so inc dental arch crowding
dental features of class II div 2
Retroclination of the upper centrals.
Upper 2’s often crowded
* Mesio-labially rotated
* May be normal or proclined depending on their position relative to the lip line
Reduced arch length
* Exacerbates crowding
Lateral incisors
* Poor cingulum – not as strong occlusal stop as teeth beyond cingulum rest
Increased Overbite (inc in inter-incisal angle)
* Lower incisors may occlude with the upper incisors or palatal mucosa
* State if av, inc, or reduced and what it is contacting
* Any indication of palatal irritation (ridging) or trauma (palatal/labial) higher tx need
Need to prioritise dealing with OB as otherwise relapse
developmental dental anomalies in class II div2
50% of cases have a form of congenital dental anomaly, 33%with impacted canine (Basdra et al 2000).
55% ≥1 developmental dental anomaly (Pereira, 2013) - knock on effect on more anomalies
* 20% impacted canine
* 15% lateral incisor microdontia
6 key dental features in class II div 2 malocclusion
- Retroclined upper and lower incisors
- Deep OB
- OJ usually reduced
- Class II buccal segments (from half unit up)
- Inc inter-incisal angle
- Upper laterals thin with poorly developed cingulum
why tx class II div 2
2
Aesthetic concern
Dental health concern
* Traumatic overbite/gingival stripping
* IOTN DHC 4f – need tx
tx options for class II div 2 depends on
4
- Severity of malocclusion (trauma, crowding, overjet etc)
- Age and motivation of patient
- Dental health
- Patients concerns – happier pt at end
orhtodontic management options for malocclusions
4
accept
growth modification
camouflage
orthognathic tx
all malocclusions have these 4 opt - tailor to pt case and age
orhtodontic management options for malocclusions
4
accept
growth modification
camouflage
orthognathic tx
all malocclusions have these 4 opt - tailor to pt case and age
when to accept class II div 2
acceptable aesthetics
Patient not concerned / not suitable
Overbite not a significant problem
IOTN DHC3 and aesthetic 6? For NHS
when to use growth modification for class II div 2
Growing patient
* Adolescent growth spurt
* Boys 14 ± 2 years
* Girls 12 ± 2 years
Mild to moderate skeletal 2 pattern
Convert Class II div 2 into Class II div 1
Detail occlusion with fixed appliances
Dentoalveolar change mainly (don’t really grow mandibles)
Dentoalveolar change mainly (don’t really grow mandibles)
functional appliances in class II div 2 for
growth modification
Proclination of upper incisors
* Modified Twin block
* Springs or screw (ELSAA screw)
* Upper sectional fixed appliance
functional appliance features for growth modification of class II div 2
Proclination of upper incisors
* Modified Twin block
* Springs or screw (ELSAA)
* Upper sectional fixed appliance
camouflage tx for class II div 2
Accepting the underlying skeletal base relationship and aiming to treat to class 1 incisor relationship
Mild to moderate Class II skeletal pattern
Careful extraction decision
* Space closure difficult in low angle cases
fixed appliance tx for class II div 2
Stable correction of class II div 2 needs
* Overbite reduction
* Correction of interincisal angle (reduction)
Overbite will relapse if not corrected
Inter-incisal angle corrected by a combination of
* Palatal root torque upper incisors
* Proclination of lower incisors
Upper incisor torqueing
* Needs adequate cancellous bone palatal to upper incisors
* Risk of root resorption – full thickness archwires can aid
orthognathic surgery for class II div2
Too severe a malocclusion for orthodontics alone
* AP, Vertical or transverse
Non growing patients (min is 18yo)
* Profile concerns
Class 2 div2, class 2 buccal segments, aim to convert into class 2 div 1 – generate OJ, allows surgeons to advance maxilla (consent them to this make it worse before get better)
stability and retention issues for class II div 2 correction
4
- Difficult to treat
- Future facial growth can affect stability
- Rotated laterals and deep overbite can relapse
Long term bonded retention usually required, as well as PFRs
when to refer class II div 2
3
Deep overbites best corrected when patient is growing - adaptive to vertical changes
* Growth modification with functional appliance if AP discrepancy
* URA with FABP
Orthognathic/Orthodontics if significant skeletal component
* After growth completed
Remember link with other dental anomalies
