Frog, a New Orthodontic Appliance for Compliance-free Molar Distalization

Objectives: to evaluate if the protocol, suggested by Forestadent, of three rotations allows to express or not the right distalization force in the Frog appliance. Methods: The mechanical behavior of the different types of springs has been evaluated by an engineering system that is able to register the force values, the Instron machine 54848. In vitro simulation is based on a support for the Frog screw: we lodged the spring into the site on the screw and we built a resistance similar to first upper molar on the opposite side of the spring. As a result of this simulation we have the chance to record the value of force sourcing from the appliance activation by the original screw driver that is delivered with the Frog. Results: The results of the first step of this study show that the forces expressed in case of personalized springs by three or five rotations of the screw are between 90 and 160 gr. The results of the second part of the study show that the 0.032 inch preformed iron springs express higher values of strength with lower numbers of activations, in comparison with 0.032 inch preformed TMA and blu-Nickel springs. Conclusions: According to most of the literature about molar distalization, we know that to obtain the bilateral first upper molar distalization we needrequires 300 gr. of force strength. To gain this value with a personalized Frog spring this study demonstrated that nine rotations of the screw were needed. Iron preformed 0.032 inch springs express high values of strength with few activations, so they have a low risk of plastic deformation and they are indicated for this kind of appliance treatment.