An 11-year-old female presented with a class II division 1 malocclusion on a moderate skeletal class II pattern with reduced vertical dimensions complicated by an increased overjet (11mm), increased overbite, generalized spacing and bi-maxillary proclination.
The aetiology of this malocclusion is multi-factorial.
The moderate skeletal class II discrepancy resulted in an increased overjet and class II molar relationship. The overjet was exacerbated by the presence of a lower lip trap. The generalized spacing was a result of an underlying dento-alveolar disproportion. This was compounded by bi-maxillary proclination, which arose due to resting soft tissue pressures and dento-alveolar compensation.
• Integration of twin block functional and sectional lower fixed Herbst appliancee • Continuation of functional appliance wear at night only • Use of headgear • Inter-arch class II elastic traction following fixed appliance placement
The prognosis for long-term stability of class II correction is good in this case, as the new maxillary incisor position will be controlled by the lower lip following the achievement of lip competence.
DEFINITION = Functional appliances are defined as ‘loose fitting or passive appliances which harness the natural forces of the orofacial musculature that are transmitted to the teeth and alveolar bone through the medium of appliance’.
Given by anderson and haul
Also called as norwegian appliance or loose fitting appliance
It doesn’t have any clasp to hold onto dentition normally
Only one wire component = labial bow
Mechanism of action 2m
Pt has to forcibly hold the appliance in its place aka maxilla as its loose appliance with no clasps
This causes the pt to bring his mandible forward and keep mouth closed so the activator doesn’t fall down.
When pt swallows = muscles get stretched, continous remodeling at TMJ and mandible stays in forward direction
Mandible is staying forward due to a REFLEX – myotatic reflex = due to continuous stretch of muscles, kinetic energy is generated and transferred to maxillary and mandibular dentition and skeletal base. Leading to:
Distal force on maxilla
Mesial force in mandible
Hence, condylar adaptation occurs
‘viscoelastic property’ = passive tension caused by stretching of muscles, soft tissue, tendinous tissue, etc. are responsible for the action
Class II division 1 malocclusion
Class II division 2 malocclusion
Class III malocclusion
Class I open bite malocclusion
Class I deep bite malocclusion
As a preliminary treatment before major fixed appliance therapy to improve skeletal jaw relations
For post treatment retention
Children with lack of vertical development in lower facial height.
Too much proclination of lower anteriors
Increased lower anterior facial height
pt can remove it
oral hygiene is maintained
no food restrictions
chair side time is less
Disadvantage = pt compliance
TYPES of activator
Horizontally growing pt
Vertically growing pt
Bite registration = gives us an idea how much mandible needs to be displaced. U shaped wax is placed on the oral cavity and asked to bring it forward and the bite is also opened posteriorly.
Acrylization of appliance
Trimming = to bring about certain movements of the dentition
WUNDERER MODIFICATION = Given in class 3
CYBERNATOR = similar to bionator = activator with reduced palatal acrylic