Sigma: importance of the first 120 days in the clinical outcome of functional orthopedic treatment

Sigma is the period of bone remodeling comprised of four phases: activation, resorption, the reverse phase and bone formation. Functional orthopedic appliances (FOA) provoke external stimuli directly at the application area, and indirectly through therapeutic posture change (TPC). The first modifications, which occur approximately 120 days after FOA use, alter the servo system through the central comparator, the occlusal comparator, the outer envelope, and the dental intercom. These changes are repercussions of the sigma period. The Objective is to demonstrate, through photos, the clinical result of the changes of the sigma period from six cases and ratify how important they are for the correct development and growth. The methodology consisted of comparison of the initial photos (intraoral – front and right/left profiles – and extraoral– front and left profile) and after 120 days of a series of six clinical cases of different malocclusions and different ages treated with FOA. After the period of 120 days, it is possible to observe clinical changes in the occlusal comparator and dental intercommunication that translate into improvement of the facial profile and lip sealing observed in the comparison of the photos.