Class II malocclusion 20 facts about treatment
Treatment of Class II malocclusion: 20 quick facts
This is going to be a list on the treatment of Class II malocclusion. I have been prompted to write this as our update of the Cochrane review on the orthodontic treatment of prominent upper front teeth (http://goo.gl/QHV2Uf) is about to be published. As a result, I thought that I should post a list of what I feel is current evidence based practice
- Treatment should be considered if the overjet is greater than 6mm. This is also the IOTN criteria
- There is an increased risk of trauma to the upper incisors particularly if the lips are incompetent. However, most trauma has occurred before orthodontic treatment can be started.
- No one ever had any problems because their molars are half a unit Class II!
- Early treatment as part of a two-phase treatment is rarely indicated as it is not effective and incurs greater cost than one course of treatment provided when the child is in adolescence.
- Early treatment costs more money
- When children have early treatment there is a 40% less chance of trauma to their upper incisors.
- Early treatment does increase the attractiveness of the facial profile and increase self-esteem. But…this effect ‘washes out’ by adolescence.
- Functional appliances are very effective at correcting Class II incisal relationships
- Functional appliances do not change the skeletal pattern to a meaningful degree.
- In adolescent treatment there is nothing wrong with extracting upper first premolars and reducing the overjet. This treatment is practiced all over the world in countries where functional appliances are not so extensively used.
- There are no differences in the treatment result of fixed and removable functional appliances
- There is greater patient co-operation with fixed functionals than removable
- The Twin Block is the most popular functional appliance in the UK.
- There is no point in putting on or leaving off the labial bow on a Twin Block.
- If headgear is used to “drive Class II molars distally” the average length of the “drive” is 1.6mm
- When a fixed functional breaks it is more hassle to repair than a Twin Block.
- We should trial functional appliance treatment against fixed appliance treatment
- The major aetiological feature of Class II malocclusion is a retrusive mandible
- The major aetiology is genetic with a small environmental component
- No orthodontist or dentist can grow a mandible!
Emeritus Professor of Orthodontics, University of Manchester, UK.