A fundamental difference in approach exists between orthodontic and orthopedic schools of thought in relation to treatment philosophy and the management of malocclusion. The past 20 years have seen an increasing awareness of the potential of functional appliances as valuable tools in the armamentaria of orthodontists. Twin blocks are simple bite blocks that effectively modify the occlusal inclined plane these devices use upper and lower bite blocks that engage on occlusal inclined planes. Twin block achieves rapid functional correction of malocclusion by transmitting favorable occlusal forces to the occlusal inclined planes covering the posterior teeth.