Which type of ligature is elastic and often used in orthodontics?

The choice of elastomeric ligature as the correct answer is appropriate because these types of ligatures are specifically designed for orthodontic applications. Elastomeric ligatures are stretchy and can be used to hold archwires in place on brackets. Their elasticity allows for a secure attachment while also providing some degree of comfort for the patient.

In orthodontics, elastomeric ligatures are available in various colors and can have an aesthetic appeal for patients, especially younger ones. This type of ligature is often preferred because it allows for gentle forces to be applied on teeth. This is crucial in guiding the teeth into the desired position over time.

Other options, such as wire ligatures, do exist but they do not have the same elastic properties and can be less comfortable for the patient. Vinyl and polymer ligatures are not typical terms used in orthodontics for ligatures; their properties are either unrelated or less suited for the specific need that elastomeric ligatures fulfill. Thus, elastomeric ligatures stand out as the best choice for this orthodontic purpose.