When is the right time to treat a class II malocclusion (abnormal posterior positioning of the lower jaw)?
In the classification of malocclusions, class II refers to a problem involving the relative backward and forward positioning of the jaws, and as such it is a skeletal problem, which can also affect the teeth. There is a difference between class II skeletal and class II dental malocclusions, but the two are very often found together.
Very often parents and high street dentists say that the upper teeth “stick out a lot”. While usually this is indeed the case, the main problem is the small size and inward position of the lower jaw.
Although it is true that the upper teeth do have a certain degree of inclination, analyzing the photo of the patient shown here (something that is part of the orthodontic analysis) clearly shows that the problem lies in the lower jaw, and that the upper teeth have slanted forward because of the patient’s thumb (if the child sucks their thumb) or because the lower lip finds its way under the upper teeth and pushes them further out – something that is seen in many cases.
Many parents come to our office with all sorts of doubts, having been to a high street dentist who has told them that their child has a malocclusion. Some dentists say treatment is required straight away whereas others say they should wait, leaving the parents in a state of some anxiety, not knowing when is best to start with the orthodontic treatment for their child.
In this blog entry I aim to clear up these doubts; my opinion is relatively objective and is based on scientific evidence. An extensive review of scientific articles has clearly demonstrated that later treatment of a class II malocclusion (during adolescence with all of the permanent teeth) has a shorter duration than earlier treatment. The specific details of the treatment times are as follows:
57 months of treatment in early mixed dentition.
33 months of treatment in late mixed dentition.
21 months of treatment in young permanent dentition.
The treatment time coincides fairly well with the treatment time for our patients treated with a Herbst appliance.
As regards the abnormal posterior positioning of the lower jaw, the conclusion of the study was that in terms of skeletal and occlusal changes and the complexity and duration of the treatment, there is no advantage gained from treatment with appliances used at pre-adolescent ages or extraoral appliances; these options do not reduce the proportion of complex treatments that require extractions or orthognathic surgery.
Personally, with these results in mind, I prefer to treat patients with class II malocclusions as late as possible, specifically, at the peak of growth or a little bit later on. However, there can be some adverse conditions that call for earlier treatment, in spite of the fact that the treatment may continue for longer and there may be a recurrence of the problem or a relapse.
Early treatment of a class II malocclusion
I prefer to go ahead with earlier treatment in three scenarios:
1. Class II malocclusion with a serious overjet problem; when there is more than 6-7 mm of overjet, because of the risk of the patient suffering from traumas in the central incisors. The goal of this treatment is to reduce the overjet – not to correct the class II malocclusion (the mandibular problem). If I am also able to improve the mandible problem then this is all the better, but it is not the primary objective. Parents are always advised about the two options and it is up to them to choose one treatment or the other.
2. For psychosocial reasons; patients with large overjets are often victims of bullying about their teeth at school. This is a very serious problem that can lead to psychological and study problems.
3. Additional problems; the other scenario in which I recommend early treatment is when the patient has other problems as well as their class II malocclusion, such as a crossbite with functional deviation of the mandible, severe crowding causing eruption and gum problems, etc. I will go into further detail on this shortly in ‘When is the right time for orthodontics?’
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