Pins

Rules For Location

 * No closer than 1 mm to DEJ if present (to avoid enamel fracture)
 * No closer than 1.5 mm to external wall of tooth if DEJ is absent (to avoid tooth fracture)
 * Pin cannot not be closer than .5 mm to a preparation(axial) wall to allow for proper amalgam condensation
 * Pins should be no closer than 3-5 mm to one another if there are multiple



Rule For Size

 * .017 and .021 inch diameter pins are normally what is used in clinic

Rule For Number of Pins:

 * 1 pin for each missing axial line angle