Final answer:
The primary incisors are the teeth most frequently injured by toddlers due to their prominence in the mouth and the developmental stage of toddlers, which includes falls and accidents.
Step-by-step explanation:
The teeth most frequently injured by toddlers are their primary incisors. Toddlers typically have up to eight deciduous teeth by the age of one year, predominantly the four upper and four lower incisors. These teeth are the sharp front teeth used for biting into food.
Considering their location and usage as well as the fact that toddlers are still developing their motor skills and are prone to falls and accidents it is the primary incisors that most commonly suffer injuries.