Which of the following is the correct plural form of this noun: tooth?

The plural of "tooth" is "teeth." This word is an example of an irregular plural noun.

Why is it "teeth" and not "tooths"?

Most English nouns form their plural by adding -s or -es (e.g., cats, boxes). However, "tooth" changes its internal vowel from oo to ee, becoming teeth. Forms like tooths or teeths are incorrect.

Examples in sentences

• “The dentist checked all my teeth.”
• “A baby’s first teeth usually appear around six months.”

Additional notes

This irregular pattern also appears in words like foot → feet and goose → geese.

According to the Cambridge Dictionary, "teeth" is the only correct plural of "tooth."