How Many Teeth Do Humans Have?
Humans have two sets of teeth: the primary (deciduous) teeth and the permanent teeth. If all teeth form correctly, twenty primary teeth and thirty-two permanent teeth are divided evenly across the top (maxilla) and bottom (mandible).
Jump Ahead
- How Many Teeth Does a Child Have?
- How Many Teeth Does a Teenager Have?
- How Many Teeth Does an Adult Have?
- Resources
How Many Teeth Does a Child Have?
By the age of three, children have twenty teeth. Dental professionals refer to this first set of teeth as deciduous or primary, as permanent teeth will ultimately replace them. On average, primary teeth emerge when a baby is six months old. This age varies among children; some get teeth earlier and some later. This first set of teeth is called the primary dentition. [1]
Primary Teeth Names – (Emergence Age)
Upper dentition (maxillary)
- (2) Deciduous maxillary central incisors (8-12 months)
- (2) Deciduous maxillary lateral incisors (9 -13 months)
- (2) Deciduous maxillary canines (16-22 months)
- (2) First deciduous maxillary molars (13-19 months )
- (2) Second deciduous maxillary molars (25-33 months)
Lower dentition (mandibular)
- (2) Deciduous mandibular central incisors (6-10 months)
- (2) Deciduous mandibular lateral incisors (10-16 months)
- (2) Deciduous mandibular canines (17-23 months)
- (2) First deciduous mandibular molars (14-18 months)
- (2) Second deciduous mandibular molars (23-31 months)
[2][3]
How the Primary Teeth Are Numbered?
According to the “Universal Tooth Designation System” created by the American Dental Association, primary teeth are lettered A-T, starting at the posterior part of the upper right quadrant where the right second molar tooth is assigned the name A, and follow around until the letter J, the left second molar on the left posterior side of the dental arch. Tooth (K) is the mandibular left second molar tooth, and lettering continues to the deciduous mandibular right second molar tooth (T). [4]
However, these primary teeth will soon give way to permanent teeth, which grow in the bone before the child is born. [5]
When Do Baby Teeth Fall Out?
Mixed dentition, that time when a child has both primary and permanent teeth, occurs around age six when the first permanent molars erupt behind the primary teeth. The mixed dentition lasts until the final primary tooth falls out around age eleven or twelve. [6]
Upper dentition (maxillary)
- (2) Deciduous maxillary central incisors (6-7 years)
- (2) Deciduous maxillary lateral incisors (7-8 years)
- (2) Deciduous maxillary canines (10-12 years)
- (2) First deciduous maxillary molars (9-11 years)
- (2) Second deciduous maxillary molars (10-12 years)
Lower dentition (mandibular)
- (2) Deciduous mandibular central incisors (6-7 years)
- (2) Deciduous mandibular lateral incisors (7-8 years)
- (2) Deciduous mandibular canines (9-12 years)
- (2) First deciduous mandibular molars (9-11 years)
- (2) Second deciduous mandibular molars (10-12 years)
[7]
When Teeth Don’t Come In
Sometimes, children are born with missing teeth, a condition known as hypodontia. Approximately 2-8% of the general population is born with hypodontia. [8]
How Many Teeth Does a Teenager Have?
The number of teeth a teenager has depends on the wisdom teeth. By the age of thirteen, a teenager has twenty-eight teeth. For most, four wisdom teeth will erupt in the later teen years or early twenties, bringing the total number of teeth to thirty-two.
How Many Teeth Do Adults Have?
If all permanent teeth erupt, an adult dentition consists of thirty-two teeth, but this number can vary. For example, according to the paper “Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment, ” between 5% and 37% of adults have missing wisdom teeth, and the number varies significantly between different ethnicities. [9]
How the Permanent Teeth Are Numbered
Utilizing the ADA’s “Universal Tooth Designation System, permanent teeth are numbered “1-32” starting with the third molar (1) on the right side of the upper arch, following around the arch to the third molar (16) on the left side, and descending to the lower third molar (17) on the left side, and following that arch to the lower right third molar (32).
Permanent Teeth Names (Emergence Age)
Upper dentition (maxillary)
- (2) Permanent maxillary central incisors (7-8 years)
- (2) Permanent maxillary lateral incisors (8-9 years)
- (2) Permanent maxillary canines (11-12 years)
- (2) First Permanent maxillary premolars (10-11 years)
- (2) Second Permanent maxillary premolars (10-12 years)
- (2) First permanent maxillary molars (5.5-7 years)
- (2) Second permanent maxillary molars (12-14 years)
- (2) Third permanent maxillary molars – wisdom teeth (17-30 years)
Lower dentition (mandibular)
- (2) Permanent mandibular central incisors (6-7 years)
- (2) Permanent mandibular lateral incisors (7-8 years)
- (2) Permanent mandibular canines (9-11 years)
- (2) First Permanent mandibular premolars (10-12 years)
- (2) Second Permanent mandibular premolars (11-13 years)
- (2) First permanent mandibular molars (5.5-7 years)
- (2) Second permanent mandibular molars (12-14 years)
- (2) Third permanent mandibular molars – wisdom teeth (17-30 years)
[10][11]
Resources
- [1][3][7] Cleveland Clinic – “Teething/Teething Syndrome.”
- [2][4][10] American Dental Association “Universal Tooth Designation System –Value Set – Version 1 – August 2022 – Page 1 of 5.“
- [5] Ten Cate’s Oral Histology, Nanci, Elsevier, 2013, pages 70-94
- [6] Ash, Major M.; Nelson, Stanley J. (2003). Wheeler’s dental anatomy, physiology, and occlusion. Philadelphia: W.B. Saunders. p. 41
- [8] Cleveland Clinic – “Hypodontia (Missing Teeth).”
- [9] Rakhshan V. “Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment.” Dent Res J (Isfahan). 2015 Jan-Feb;12(1):1-13. doi: 10.4103/1735-3327.150286. PMID: 25709668; PMCID: PMC4336964.
- [11] Aruede G, Pepper T. “Anatomy, Permanent Dentition.” [Updated 2023 May 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
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