2021 Jacob A. Salzmann Award Lecture; Efficient and Effective Growth Modification: A 30-year Perspective Lorenzo Franchi
Class 2
Timing of treatment
· Mandibular growth (Co-Gn) Pre-pubertal Vs pubertal = pre-pubertal 0.9mm Vs 2.9mm pubertal Systematic review Perinetti 2015
· What happens in pre-pubertal class 2 treatment
o Mainly dentoalveolar effects, lip competence improves
o No change to skeletal structures
· Case of patient 11 years old at CVM 3
o 9mm of mandibular growth with twinblock appliance
Favourable features at the growth spurt
· Predictable growth = 3mm from systematic review Perinetti (short term outcomes)
· Efficient – shorter overall duration 2.5 years Vs 4 years Tulloch 2004
· Good stability: Baccetti 2009
Long term effects of functional treatment Systematic review Pavoni 2018
· Treatment and controls of prepubertal Vs pubertal (Prepubertal CVM 1&2, Pubertal CVM 3)
· Prepubertal group = no difference in mandibular growth in the treatment functional group Vs control
o Understanding = in prepubertal patients mandibular growth is accelerated during functional appliances however growth decelerates in the treatment group when compared to the control.
· Pubertal group = 5.5mm mandibular growth when compared to control
· Long term growth is maintained when compared to controls approx. age of 18 (CVM 5&6)
o Understanding = during puberty functional appliance stimulate mandibular growth
Individual response
Predictor factors
· Mandibular angle Co-Go-Me Franchi 2006
o Great responder: >123
o Good responder: 124-128
o Poor responder: <128
· Greater advancement of soft tissue chin with Co-Go-Me less than 123 Baccetti 2009
Conclusion:
· Timing of treatment = CVM 3
· Predictable outcome = Mandibular angle
Class 3 cases
Treatment timing
· Franchi 2004 RME and facemask use
o Before puberty (CVM 1) significant maxillary growth 2mm maxillary advancement
o At puberty (CVM 3) only significant mandibular growth
· Explanation
o Maxillary sutures timing of closing = resistance to protraction
§ Pterygopalatine sutures are open prior to puberty
§ During puberty significant bony interdigitation
§ Zygomaticmaxillary suture can produce a significant resistor to maxillary protraction
· CBCT classification A-E Angelieri 2013/2017
· Least resistance in pre-pubertal patients CVM1 and CVM 2
Individual patient response
Long term outcomes of class 3 cases with RME and facemask, followed by fixed appliances, in pre-pubertal (7.1 years) Souki 2019. Long term age 21 years
· Clinical outcomes = success, absence crossbite, skeletal 3
· Successful outcome = 70%
· Predictor factor
o Condylar axis – Mandibular plane
§ Condylar axis= from point condyle passing through midpoint : between Ar-Ar anterior
o Unsuccessful > 147
o Successful <147
Predictor = Specificity – 98%, sensitivity 86%
Conclusion
· Treatment time – pre puberty
· Predictable outcome – Condylar axis <147
· Longterm success 70%
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