"Artificial teats" refer to man-made nipples or devices used to feed or nurse young animals, typically when their natural mother is unable or unavailable to do so. Full definition
Whenever a substitute for sucking at the breast is used, a pacifier or other artificial teat, there is a risk of affecting the breastfeeding relationship. (breastfeedingtoday-llli.org)
However, an artificial teat is already formed, with a specific shape, and is made from a material stiffer than breast tissue. (brianpalmerdds.com)
(Sucking on a breast requires a lot more effort on the baby's behalf and a different technique to get milk than sucking on an artificial teat.) (breastfeedingmums.com)