Which component is used to adjust the tension of the matrix band?

The outer nut is used to adjust the tension of the matrix band. This component is typically part of the matrix band retainer assembly, which holds the matrix band in place during restorative procedures. By turning the outer nut, the dental professional can increase or decrease the tension on the band, allowing for better adaptation around the tooth and achieving a more accurate cavity preparation. Proper tension is crucial for ensuring that the restorative material can be placed properly and contours correctly to the natural tooth structure, which ultimately helps achieve a successful and lasting restoration.

While other components like the spindle and inner nut play roles in the mechanism of the retainer, it is the outer nut that specifically regulates the tension necessary for the effectiveness of the matrix band during dental treatment.