List indications for periodontal ligament (PDL) injections

What will be an ideal response?

PDLs are indicated as a primary method of anesthesia for single teeth, for supplemental anesthesia of individual teeth when other techniques have failed to provide profound anesthesia, when widespread anesthesia is contraindicated, and when total doses need to be minimized. The PDL technique can also be beneficial for individuals with bleeding disorders and when needle insertions into vascular regions may be a risk.