Modified Twin Blocks: fabrication method and use in a child with a Class II malocclusion

The twin blocks technique was developed by Dr. William Clark of Scotland during the early 1980s. Twin Blocks are an uncomplicated system that incorporates the use of upper and lower bite blocks. These bite blocks reposition the mandible and redirect occlusal forces to achieve rapid correction of malocclusions. They are also comfortable and the patients wear them full-time--including eating time. Occlusal forces transmitted through the dentition provide a constant proprioceptive stimulus to influence the rate of growth and the trabecular structure of the supporting bone. This feature of Twin Blocks means easier and quicker treatment. The occlusal inclined plane is the fundamental functional mechanism of the natural dentition. Twin Blocks are bite blocks that effectively modify the occlusal inclined plane to induce favorably directed occlusal forces by causing a functional mandibular displacement. Upper and lower bite blocks interlock at a 45 degree angle and are designed for full-time wear to take advantage of all functional forces applied to the dentition including the forces of mastication. The patients who were treated with Modified Twin Blocks received the following benefits: 1) large overjets and deep overbites were corrected. 2) Class II molar relationships were changed into Class I, and 3) the profiles of the patients were improved by anterior displacement of mandible.