The plural of tooth is teeth. Use tooth for one individual structure and teeth for two or more, as in “I chipped a tooth” and “I brush my teeth twice a day.” Tooths and teeths are not standard plural forms in modern English.
Key Facts at a Glance
- Tooth is the singular noun; teeth is its irregular plural.
- The plural teeth changes the internal vowel instead of adding -s.
- Standard English does not use tooths or teeths for ordinary plural meaning.
- Most adults have 32 permanent teeth if all four wisdom teeth are present.
- Children usually develop 20 primary teeth, also called baby, milk, or deciduous teeth.
- The possessive forms are tooth’s for one tooth and teeth’s for multiple teeth.
What Is the Plural of Tooth?
The plural of tooth is teeth, and the change is irregular because English alters the word’s vowel rather than adding a regular plural ending. “One tooth,” “two teeth,” “a painful tooth,” and “healthy teeth” are all standard constructions.
The word teeth can refer to human or animal dentition. A veterinarian might write, “The dog’s teeth need cleaning,” while an engineer might describe “the teeth of a gear.” The grammatical form remains the same even when the physical object changes.
| Meaning | Correct singular | Correct plural | Example |
|---|---|---|---|
| Human dental structure | tooth | teeth | One tooth is sensitive; several teeth hurt |
| Animal dental structure | tooth | teeth | The shark loses teeth continuously |
| Gear projection | tooth | teeth | The gear has 24 teeth |
| Comb projection | tooth | teeth | The comb has wide teeth |
| Saw projection | tooth | teeth | The saw’s teeth are dull |
Is “Tooths” Ever Correct?
Tooths is incorrect in standard modern English when you mean more than one tooth. A learner may form it by applying the ordinary plural rule used in “book/books” or “chair/chairs,” but tooth belongs to a small group of irregular nouns with historical vowel changes.
Some dialects, fictional speech patterns, or language-learning errors may contain tooths, but those uses do not make the form appropriate in formal writing, schoolwork, medical communication, or edited publishing.
Is “Teeths” Correct?
Teeths is also incorrect as the ordinary plural of tooth. Because teeth already means more than one tooth, adding -s creates a nonstandard double plural.
Correct:
- “My teeth are sensitive.”
- “The dentist examined three teeth.”
- “The crocodile has many teeth.”
Incorrect in standard English:
- “My teeths are sensitive.”
- “The dentist examined three tooths.”
- “The crocodile has many teeths.”
Why Does Tooth Become Teeth?
Tooth becomes teeth through historical vowel mutation, an Old English process often called i-mutation or umlaut. An early plural ending influenced the vowel in the root of the singular word, and later sound changes removed the ending while preserving the altered vowel.
The modern pair developed from older Germanic forms. English once used more visible endings, but pronunciation gradually changed and the plural ending weakened or disappeared. The vowel distinction survived, producing the modern relationship between tooth and teeth.
The same historical pattern appears in several familiar pairs:
| Singular | Plural | Internal change |
|---|---|---|
| tooth | teeth | oo changes to ee |
| foot | feet | oo changes to ee |
| goose | geese | oo changes to ee |
| mouse | mice | ou changes to i |
| man | men | a changes to e |
| woman | women | internal vowel and pronunciation change |
The pattern is historical rather than productive. Modern speakers do not normally create new plurals by changing vowels. For example, book becomes books, not beek, and computer becomes computers, not an internally modified form.
Why Is Tooth an Irregular Noun?
Tooth is irregular because its plural does not follow the productive English rule of adding -s or -es. English inherited the vowel-changing pattern from Germanic languages, whereas newer nouns generally form plurals with a suffix.
The term “irregular” describes the relationship between the modern singular and plural. It does not mean the word lacks a rule. The rule is simply historical and must usually be learned as a vocabulary pair: tooth, teeth.
How Do You Use Tooth and Teeth in a Sentence?
Use tooth after singular expressions such as “a,” “one,” “each,” and “every.” Use teeth after numbers greater than one, plural determiners, and expressions such as “many,” “several,” and “both.”
| Situation | Correct form | Example |
|---|---|---|
| One object | tooth | A tooth is loose |
| More than one | teeth | Two teeth are loose |
| Singular indefinite article | tooth | She broke a tooth |
| Plural number | teeth | He lost four teeth |
| Each individual item | tooth | Each tooth has a root |
| Entire group | teeth | All the teeth were examined |
A useful test is to replace the noun with one or several. “One tooth” is correct, so “several teeth” is the corresponding plural. The verb must also agree: a tooth is, but teeth are.
Tooth or Teeth in Common Expressions
Common expressions preserve the same grammatical distinction:
- Tooth and nail: with maximum effort or resistance.
- By the skin of one’s teeth: by a very narrow margin.
- Long in the tooth: old or aging.
- Sweet tooth: a strong preference for sweet foods.
- Armed to the teeth: heavily equipped.
- Lie through one’s teeth: lie deliberately and openly.
In sweet tooth, the phrase refers to a preference, not necessarily to one literal tooth. In teeth of a comb or teeth of a saw, the plural describes repeated projections arranged along an object.
What Is the Possessive Form of Tooth?
The singular possessive is tooth’s, while the plural possessive is teeth’s when the plural noun does not end in -s. Use tooth’s for something belonging to one tooth and teeth’s for something belonging to multiple teeth.
| Meaning | Possessive form | Example |
|---|---|---|
| One tooth owns or has something | tooth’s | The tooth’s enamel is damaged |
| Multiple teeth own or have something | teeth’s | The teeth’s surfaces were polished |
| Multiple teeth as a noun phrase | teeth | The teeth are clean |
| A compound modifier | tooth | Tooth enamel protects the crown |
| A compound modifier | teeth | Teeth whitening can reduce stains |
The phrase teeth’s enamel is grammatically possible but less common than the enamel of the teeth or tooth enamel. Writers often choose the longer construction because it is clearer in technical or medical prose.
Do not confuse the possessive apostrophe with a plural ending. Teeth is plural without an apostrophe, while teeth’s indicates possession.
How Do You Pronounce Teeth?
Teeth is pronounced /tiːθ/, with a long “ee” vowel and the unvoiced “th” sound at the end. The singular tooth is pronounced /tuːθ/, so the main vowel changes from the sound in “food” to the sound in “see.”
| Word | IPA | Approximate comparison |
|---|---|---|
| tooth | /tuːθ/ | rhymes with “booth” |
| teeth | /tiːθ/ | begins like “tea” |
| tooths | /tuːθs/ | nonstandard ordinary plural |
| teeths | /tiːθs/ | nonstandard double plural |
The final sound in teeth is the voiceless “th” heard in think, not the voiced sound heard in this. The plural does not sound like “teeth-ee” and does not take an additional syllable.
In connected speech, the final consonant can become less distinct before another consonant, but careful pronunciation retains the th sound. Medical professionals, teachers, and presenters generally use the same pronunciation in every formal context.
How Many Teeth Do Humans Have?
Children usually have 20 primary teeth, while adults can have 32 permanent teeth when all four wisdom teeth are present. Many adults have 28 visible permanent teeth because one or more third molars were removed, never erupted, or never developed.
Primary teeth usually begin appearing around six months of age, although normal timing varies. By approximately age three, many children have the full set of 20 primary teeth. Permanent teeth generally begin replacing them around age six and continue erupting into the late teens or early twenties.
| Tooth type | Primary dentition | Permanent dentition | Main function |
|---|---|---|---|
| Incisors | 8 | 8 | Cutting and biting |
| Canines | 4 | 4 | Tearing and gripping |
| Premolars | 0 | 8 | Crushing and transitional chewing |
| Molars | 8 | 12 | Grinding |
| Total | 20 | 32 | Complete dental set |
Primary teeth do not include premolars. Permanent premolars replace the primary molars, which explains why the two life stages have different tooth-type counts.
What Are Wisdom Teeth?
Wisdom teeth are the four permanent third molars located at the back of the mouth. They are included in the theoretical adult count of 32, but many people have fewer than four because of extraction, impaction, missing development, or failure to erupt.
Wisdom teeth commonly emerge between the late teenage years and the mid-twenties, but timing varies widely. A wisdom tooth can be healthy and functional, or it can create crowding, gum inflammation, decay, or difficulty cleaning when the jaw lacks sufficient space.
A numerical statement such as “adults have 32 teeth” describes the complete standard arrangement, not a guarantee about every individual. Dental records usually distinguish erupted, unerupted, extracted, and congenitally missing teeth.
What Is the Difference Between Tooth, Teeth, and Dentition?
Tooth names one structure, teeth names multiple structures, and dentition names the complete arrangement of teeth in a mouth. Dentition is a technical collective noun used in anatomy, dentistry, zoology, and developmental biology.
| Term | Number meaning | Typical context | Example |
|---|---|---|---|
| tooth | One | Everyday and clinical English | A tooth has enamel |
| teeth | Two or more | Everyday and clinical English | The teeth are aligned |
| dentition | A complete arrangement | Anatomy and dentistry | Primary dentition has 20 teeth |
| dental | Relating to teeth | Adjective | Dental treatment was scheduled |
| odontogenic | Originating from tooth tissue | Medical terminology | An odontogenic cyst was diagnosed |
Teeth is countable and normally takes a plural verb. Dentition often refers to a system or developmental stage rather than a count of individual structures.
The adjective dental does not become “teethal.” Writers use dental examination, dental enamel, and dental health to modify nouns related to teeth.
What Are the Most Common Tooth Grammar Mistakes?
The most common error is replacing teeth with tooths, usually because the writer applies the regular plural rule without memorizing the irregular form. The second common error is adding -s to teeth, producing teeths.
Correct these mistakes with four checks:
- Replace tooths with teeth when referring to multiple structures.
- Remove the final s from teeths in ordinary standard English.
- Match the verb to the noun: “the tooth is,” but “the teeth are.”
- Use tooth’s or teeth’s only when showing possession.
A less obvious error involves number words. “Each teeth” is incorrect because each requires a singular noun. The correct sentence is “Each tooth was cleaned.” Conversely, “many tooth” is incorrect because many requires a plural noun: “many teeth.”
Can Tooths Be Correct in a Technical Context?
In ordinary modern English, tooths is not the accepted plural of the dental noun tooth. Specialized terminology can occasionally preserve unusual forms, and historical texts may show older spellings, but those exceptions do not change the standard answer for contemporary writing.
Writers describing gears, saws, combs, or animal anatomy should still use teeth. For example, “the gear has 40 teeth” and “the saw’s teeth are worn” are standard technical sentences.
Is Teeth Singular or Plural?
Teeth is plural, and tooth is singular. Use a singular verb with tooth and a plural verb with teeth: “The tooth is cracked” versus “The teeth are healthy.”
The pair behaves like other irregular noun forms such as foot/feet and goose/geese. A sentence such as “One teeth is loose” combines a singular number with a plural noun and is therefore incorrect.
| Incorrect sentence | Correct sentence | Reason |
|---|---|---|
| One teeth is loose | One tooth is loose | One requires singular |
| Two tooth are loose | Two teeth are loose | Two requires plural |
| My teeth is sensitive | My teeth are sensitive | Teeth is plural |
| Each teeth needs care | Each tooth needs care | Each requires singular |
How Should You Remember the Plural of Tooth?
Remember the pair as a fixed vocabulary unit: one tooth, two teeth. Linking it with one foot, two feet provides a practical memory aid because both words use the same historical vowel pattern.
A short sentence drill reinforces the distinction:
- “I have one sore tooth.”
- “My other teeth feel normal.”
- “The dentist examined both teeth.”
- “The tooth’s crown is damaged.”
- “The teeth’s alignment changed.”
The most reliable learning method is active contrast. Say or write the singular and plural together rather than memorizing teeth in isolation.
FAQ About Tooth and Teeth
What Is the Plural of Baby Tooth?
The plural of baby tooth is baby teeth, not baby tooths. “Baby teeth” is the everyday term for the 20 primary teeth that children develop, while primary teeth, milk teeth, and deciduous teeth are also standard terms.
What Is the Plural of Tooth Fairy?
The plural of tooth fairy is tooth fairies because the compound noun’s principal noun, fairy, changes from -y to -ies. The word tooth remains singular inside the compound: one tooth fairy, two tooth fairies.
Is “Teeth” Countable?
Yes. Teeth is the plural of a countable noun, so speakers can say “two teeth,” “several teeth,” or “32 teeth.” The word may also appear in technical phrases describing a group, such as “the teeth of a gear,” while retaining its countable meaning.
Why Do We Say “Brush Your Teeth” If a Person Brushes Each Tooth Separately?
“Brush your teeth” refers to the complete set of teeth as a group. The instruction is collective, even though brushing physically involves individual teeth and surfaces. “Brush each tooth carefully” is also grammatical when the instruction emphasizes individual structures.
What Is the Plural of a Tooth in Animal Anatomy?
The plural remains teeth for animals. Standard examples include “shark teeth,” “dog teeth,” “snake teeth,” and “elephant teeth.” Species-specific anatomy may use terms such as incisors, canines, molars, tusks, or dentition, but the ordinary plural of tooth does not change.
What Is the Difference Between Teeth’s and Teeth?
Teeth is the plural noun, while teeth’s is a possessive form. “The teeth are clean” states that multiple teeth are clean; “the teeth’s surfaces are clean” indicates that the surfaces belong to or are associated with those teeth. “The surfaces of the teeth” is often clearer.
The Bottom Line
The plural of tooth is teeth. Use tooth for one structure, teeth for more than one, tooth’s for the possessive singular, and teeth’s for the possessive plural. Standard English does not use tooths or teeths as the ordinary plural forms.
