Ortho Case 4.2

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
• 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.

Adenoid Faces

  1. Head is tilted backwards
  2. Anterior open bite
  3. Increased overjet/ Proclined anterior teeth
  4. Crowding seen in anterior segment 
  5. Supra erupted posterior 
  6. Posterior crossbite
  7. Narrow maxilla and deep palatal vault
  8. Xerostomia = prone to caries
  9. Gingival recession
  10. Bleeding from gums
  11. Narrow nasal passages

Cantilever spring/ Finger spring 2m** = 

  1. used for mesiodistal tooth movement. 
  2. Active arm is 12 mm and retentive tag is 3-5mm. 
  3. Placed along long axis of the tooth which has to be moved. 
  4. If tooth is to be moved mesially, direction of helix will be distal
  5. The finger spring is activated by moving the active arm towards the teeth intended to be moved. This is done as close to the coil as possible.
  6. Activation of upto 3 mm is considered 


Defined as correctly timed, planned removal of certain deciduous and permanent teeth in mixed dentition cases with dentoalveolar disproportion

  1. Introduced by KJELLGREN 
  2. Father of SE = nance 1940
    1. Arch length deficiency as compared to the tooth material using Model analysis method
    2. Physiological tooth material = eg wilkinson extraction of 1st permanent molar
    1. Leeway space of nace 
      1. Max = 1.8 mm
      2. Mand = 3.4 mm
    2. Tongue pressure 
    3. Interdental spacing 
    4. Incisal liability = amount of space available and required by permanent tooth
      1. Max = 7 mm
      2. Mand = 5mm 
    1. Tooth material and arch length discrepancy of 10mm
    2. Class I malocclusion 
    3. Absence of Spacing 
    4. Midline shift 
    5. Premature loss of primary canine
    1. Class II and Class III malocclusion 
    2. Anodontia
    3. Oligodontia
    4. Deep bite 
  7. ADVANTAGES =  Prevents fixed appliances and malocclusions in the pt
    1. Long follow up = pt compliance
    2. Operator = highly trained 
    3. Delay of permanent tooth 
    1. Extraction of three teeth 
      1. Primary canine = at age of 8-9 years
      2. Primary 1st molar = at age of 9-10 years
      3. 1st premolar 
    2. Always bilateral extraction in the same arch 
    3. If done unilateral = midline shift happens 
    4. In the 1 st Step, the deciduous canines are extracted to create a space for alignment of the incisors. This step is carried out at 8-9 years of age. 
    5. After 1 years, the deciduous 1st molars are extracted so that the eruption of 1st premolars is accelerated. 
    6. This is followed by the extraction of the erupting 1 st premolar to permit the permanent canines to erupt in their place. 
  • BOTH methods involve the extraction of the deciduous 1 st molars around 8 years of age. This is followed by the extraction of the 1 st premolar & the deciduous canines. 
  • MOYERS METHOD = based on intercanine width = BCD4
    1. Maxillary arch 
      1. Boys = 10 years
      2. Girls = 9 years
    2. Mandibular arch 
      1. Boys = 18 years
      2. Girls = 12 years


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’.


  1. Given by anderson and haul
  2. Also called as norwegian appliance or loose fitting appliance
  3. It doesn’t have any clasp to hold onto dentition normally 
  4. Only one wire component = labial bow

Mechanism of action 2m

  1. Pt has to forcibly hold the appliance in its place aka maxilla as its loose appliance with no clasps
  2. This causes the pt to bring his mandible forward and keep mouth closed so the activator doesn’t fall down. 
  3. When pt swallows = muscles get stretched, continous remodeling at TMJ and mandible stays in forward direction
  4. 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: 
    1. Distal force on maxilla
    2. Mesial force in mandible 
    3. Hence, condylar adaptation occurs
  5.  ‘viscoelastic property’ = passive tension caused by stretching of muscles, soft tissue, tendinous tissue, etc. are responsible for the action

Indications 2m

  1. Class II division 1 malocclusion
  2. Class II division 2 malocclusion
  3. Class III malocclusion
  4. Class I open bite malocclusion
  5. Class I deep bite malocclusion
  6. As a preliminary treatment before major fixed appliance therapy to improve skeletal jaw relations
  7. For post­ treatment retention
  8. Children with lack of vertical development in lower facial height.


  1. Crowding 
  2. Adult pt 
  3. Too much proclination of lower anteriors 
  4. 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 

  1. H activator 
    1. Horizontally growing pt
  2. V activator 
    1. Vertically growing pt 


  1. Take impression
  2. 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. 
  3. Articulation
  4. Wire elements  
  5. Acrylization of appliance
  6. Trimming = to bring about certain movements of the dentition



  • WUNDERER MODIFICATION = Given in class 3 
  • CYBERNATOR = similar to bionator = activator with reduced palatal acrylic 
  • Cutout or palate free activator
  • Karwetzky modification 
  • Herren modification 
  • Elastic open activator
  • Kinetor by Stockfish