Anterior open bite and tongue positions, DPJO

A very interesting article can be found at the current issue of the Brazilian journal. The anterior open bite patients are among the hardest ones to treat, and the most common complication is the relapse of the treatment result even after complete closure of the open bite.

By looking a little more into the reason that created the malocclusion we can try to enhance our treatment results. The equilibrium theory is know from Proffit, and from studies of researchers like Thüer in the 80ies. It is according to those beliefs that the equilibrium between the tongue function and position, and the lips assures a perfect inter-incisal angle and stability at the front region.

Take a look at this scheme of different tongue positions, taken from the article:

The first one is the normal position of the tongue, showing the forces exerted upon swallowing.

Meta analysis, of stability of anterior open bites, Feb AmJO 2011

G. M. Greelee et al, performed an interesting meta analysis on a topic that is quite hot, for the orthodontic world. Anterior open bite patients and the stability of closure treatments wether this is a surgical or a non surgical approach. This meta analysis is published at the current issue of the American Journal of Orthodontics and Dentofacial Orthopedics


The initial search was done at PubMed, EMBASE, Cochrane Library, gray zone literature and hand searching. It was performed using the abstracts of 105 articles initially.


From those 21 articles met the criteria. The articles that were excluded did not have:

Design and Management of Twin Blocks

William Clark published recently an article at the British Journal of Orthodontics.


Design and Management of Twin Blocks: Reflections After 30 Years of Clinical Use


As the abstract reads:
There is an amount of misconceptions concerning the design of the Twin Block appliance. Those misconceptions might lead to poor compliance and poor treatment results and discourage some clinicians from the use of the appliance.


Small note: This post will not go into the principle and the basics of the Twin Block therapy as it's aim is to discuss the common mistakes when constructing the appliance. As such it is mend for readers with prior clinical experience using the appliance. 




Height of Occlusal Blocks


The height of the occlusal blocks should be enough to overcome the freeway space and not allow the patient to retrude the mandible when at rest. However constructing very high blocks would give other undesired complications.


Patient has to be able to close the lips without major strain, to be able to incise and chew posteriorly without difficulty, not to affect his/her speech, and not compromise the aesthetics when worn. These will ensure compliance and full time wear of the appliance which is the goal for the Twin Block therapy.


What is commonly used among clinicians is the rule of 2mm inter-incisal clearance, that will give a 5-6mm opening at the first premolar region. However this is not the case for all starting malocclusions, and that is one of the most common mistakes.

Masticatory muscle activity in children with a skeletal or dentoalveolar open bite.

The article is published at the European Journal of Orthodontics of this August, and it aims to compare the electomyographic characteristic of masticatory muscles, in children 6-11 years of age. The group that made the study is from Sao Paolo, Brazil


Material:

• 15 children with skeletal anterior open bite (SAOB)
• 15 children with dentoalveolar open bite (DAOB)
• and 15 children of normal occlusion as a control group (CG)