Tweed-Merrifield sequential directional force treatment.

There are essentially five concepts which comprise the modern Tweed-Merrifield Sequential Directional Force treatment philosophy. These concepts are: (1) sequential appliance application, (2) sequential and/or individual tooth movement, (3) sequential mandibular anchorage preparation, (4) directional forces which control the vertical dimension to enhance mandibular response, and (5) proper timing of treatment. Tweed-Merrifield Sequential Edgewise Directional Force Treatment can be organized into four steps: denture preparation, denture correction, denture completion, and denture recovery. During each of these steps, there are certain treatment objectives that must be attained. This article outlines the modern Tweed-Merrifield treatment concept.