Part 1 explores key themes around the effectiveness of class 2 correction, how they work, different times, the role of headgear and fixed functional appliances.

Q1 & 2 Do we have the evidence, and is it effective?

Phase 1

o Phase 1 there is no advantage, no difference in clinical outcomes: Cochrane review Harrison 2007.

o 9-10% of patients benefit from phase 1 through a reduction in trauma, Gianelly 1995.

o “Just because we can doesn’t mean we should” Jay Bowman

Trauma

· Increased OJ greater than 3mm = 2 x risk of trauma Nguyen 1999

Questions 3 Growth can we predict it?

· No restraining effect on Maxilla, slight growth of the mandible and increase vertical growth Mills 1991

o 3mm growth Pg-Go

o SNB improvement of  4o

o NO we cannot - Unpredictable

Question 4 When to treat and which on?

· When: CVM 3-4 is where peak growth occure, (PHV): however only 25% of patients have 1 single peak, most have ‘multiple peaks’

· Which one: Efficiency- Herbst 0.28mm, TB 0.23mm, Herbst more efficient  - fixed more efficient

Question 5 What changes take place?

Functional appliances don’t all work the same:

· Removable:

o Upper molar distalisation / upright

o Upper incisor uprighting

· Fixed

o Upper molar distalisation / upright

o Increase mandibular length (Po-Go)

Question 6 Do they grow mandibles?

· AAO Council statement 2005 – “No scientific evidence of increase in mandible”

o Lengthening of condyle and ramus does occur.

o Glenoid fossa remodelling does occur.

o No evidence shows:

§ Insignificant overall increase in length .

§ Condyle growth cannot be permanently increased.

Question 7 Does HG still have a role?

· Vertical and AP changes do occur with HG after 6/12 Burke 1992, Nanda 2006,

· Compliance however is 56% Brandao

Question 8 Effectiveness of fixed functional appliances?

· Compliance nearly 100%

· Phase 1 shorter 4.5 months

· Forsus Vs Powerscope:

o More AP change with Forsus Arora 2018

· New ideas of fixed functional and TAD  / miniplates

References

Harrison, J.E., D O'Brien, K. and Worthington, H.V., 2007. Orthodontic treatment for prominent upper front teeth in children. Cochrane Database of Systematic Reviews, (3)

Nguyen, Q.V., Bezemer, P.D., Habets, L.L.M.H. and Prahl-Andersen, B., 1999. A systematic review of the relationship between overjet size and traumatic dental injuries. European Journal of Orthodontics, 21(5), pp.503-515.

Mills, J.R.E., 1991. The effect of functional appliances on the skeletal pattern. British Journal of Orthodontics, 18(4), pp.267-275.

Vaid, N.R., Doshi, V.M. and Vandekar, M.J., 2014, December. Class II treatment with functional appliances: A meta-analysis of short-term treatment effects. In Seminars in Orthodontics (Vol. 20, No. 4, pp. 324-338). WB Saunders.