Figure 3
From: Evaluation of mechanical properties of three different screws for rapid maxillary expansion
The specimens were arranged in Instron testing machine. The expander was placed on the Instron 3365 machine with a load cell of 5 kN by grabbing the arms bent at tooth level with the upper and lower clamps of the machine. The activations were performed by means of a stainless steel (AISI 302) key with a diameter of 1 mm. The key was inserted fully into the holes of the screw.