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.
