Final answer:
The correct answer is option 4) Ligature-tying pliers. The instrument used in the placement of elastomeric ligature ties is Ligature-tying pliers. This tool is specifically designed for securely attaching the elastic ties to brackets during orthodontic treatment.
Step-by-step explanation:
These specialized pliers are designed for the placement of elastomeric ligature ties, which are small rubber bands or elastic rings used in orthodontic treatment to secure the archwire to the brackets on a patient's teeth. The ligature-tying pliers have a small, grooved tip that holds the elastomeric ligature tie until it is wrapped around the bracket. While other instruments like locking hemostats may superficially resemble ligature-tying pliers, they are not specifically designed for this sensitive and precise task.
Elastomeric ligature ties are important in maintaining the pressure needed to move teeth into the desired position. The ligature-tying pliers' design allows orthodontists to place the ties quickly and efficiently, minimizing discomfort for the patient and ensuring the ligature is properly secured.