Growth Modulation by class 2 and class 3 orthopedics Hugo De Clerck
Bone anchored Maxillary Protraction BAMP
Main reason for failure- surgical insertion Website www.lesschin.com, information for patients, orthodontists and surgeons
· Effects
· Protraction of the maxilla 5.2mm, when compared to PFM 2.3mm Cevidanes 2010, 5.8mm BAMP Vs 4.9mm Einagar 2016
· Maxillary protraction: Zygomatico-frontal and zygomatico-termporal most effected, not the larger zygomatico-maxillary suture
Maxillary / Mandibular rotation
· Herbst: Posterior rotation of the maxilla (clockwise rotation) as molars intrude Pancherz 2002
· BAMP / PFM anterior rotation, Upper molar moves downwards
o PFM posterior rotation mandible = increase in LAFH
· BAMP
o Line of action above condyle = anterior rotation of mandible lnagar 2016
Condyle changes
· Class 2 condyle grows forwards, class 3 grows backwards
· BAMP: condyle moves forwards
· Herbst: condyle moves backwards
o BAMP -= Posterior displacement of the condyle
§ Tension anterior, compression posterior
§ =Resorption posterior condyle, deposition anterior = displacement of condyle forwards
· Herbst condyle is pulled forward
o Resorption anterior, apposition nposterior
o Condyle develops backwards
Gonial angle Enlow
· Gonial angle remodelling linked to AP and vertical growth
· Opening of the gonial angle in class 3
· Closing of gonial angle in class 2 Jacob 2013
· Gonial angle is the determinant of AP growth
· BAMP = closure of Gonial Angle
Time line for class 3 orthopedics
Gonial angle changes during 11-13 years of age
Modelling changes can go on much longer
Strain growth of the mandible
BAMP closing of the gonial angle 4 degrees
Elastic force of class 3 elastics
· Extrude upper molar
· Extrusion of anterior teeth
· Reduce gonial angle 4 degrees
· Direction of condylar growth due to changes of the closing of the condyle
Class 2
Can the gonial angle be opened
· Systematic review, inconclusive regarding mandibular growth
· Non-systematic review De Clerck
o Skeletal Go +0.05
o Dental Li 10, Ui -4
· Mandibular changes in Herbst Vs control Souki 2017
o Proclination of lower icnisors
o Herbst condyle growth similar to class 3 growth = backwards
How does growth occur at the condyle
· No change at the condyle head, but at the condylar neck through tension of the nec
