The Primary Dentition are the first set of teeth that develop in the human oral cavity. They are often referred to as the baby teeth or the deciduous teeth. There are 20 primary teeth—10 maxillary and 10 mandibular. They perform several important functions, including aiding in the chewing and digestion of food, and aiding in speech and pronunciation. The primary dentition guides the eruption of the permanent teeth.
One of the most important factors in the eruption of the permanent teeth is that the proper space required is available. This space is maintained by the retention and timely exfoliation (shedding) of the primary dentition. So, the primary teeth also function as the Natural Space Maintainer for the permanent dentition. Any premature or delayed exfoliation of the primary dentition may cause problems with secondary tooth eruption.
Teeth of the Maxillary Arch
Primary Dentition Central Incisor
The primary central incisor is located in the front of the maxillary arch. It is utilized for cutting and dividing food items. Eventually, it is replaced with the permanent central incisors.
Primary Lateral Incisor
The primary lateral incisor performs the same function as the central incisor. However, it is slightly smaller than the central incisor. The permanent lateral incisor replaces it.
Primary Cuspid (also known as Canine)
The primary cuspid (primary canine) is the cornerstone of the primary dentition. It is utilized for tearing and shredding of food particles. It also maintains the arch integrity. Premature loss of this tooth can cause arch disharmony. The primary cuspid (canine) is replaced by the permanent cuspid (canine). The cuspids, along with the central and lateral incisors, are called the anterior teeth.
Primary First Molar
The primary first molar is used for grinding and pulverizing food. It resembles the permanent first molar. However, it is replaced by the permanent first premolar.
Primary Second Molar
The Primary Dentition second molar is the largest of the primary teeth. It helps to grind food. The permanent second premolar eventually replaces this tooth.
Teeth of the Mandibular Arch
Primary Mandibular Central incisor
The primary mandibular central incisor is the smallest tooth in the primary dentition. The mandibular permanent central incisor replaces it, which is also the smallest in the mandibular permanent arch.
Primary Mandibular Lateral Incisor
The Primary Dentition mandibular lateral incisor resembles the central incisor. However, it is slightly larger then central incisor. The permanent lateral incisor replaces this tooth.
Primary Mandibular Cuspid
(also known as Canine)
The primary mandibular cuspid (canine) serves the same function as the maxillary canine, that of tearing and shredding food. It causes stabilization of the mandibular arch. It is replaced by the permanent cuspid.
Primary Mandibular First Molar
The primary mandibular first molar grinds and breaks up food items. It is eventually replaced by the permanent first premolar.
Primary Mandibular Second Molar
The primary mandibular second molar is the largest mandibular tooth. The permanent second premolar eventually takes the place of this tooth.
The Eruption of Primary Dentition
Primary Dentition Eruption Age (in months)
- Maxillary Arch (Upper teeth)
- Central Incisor 8—12 months
- Lateral Incisor 9—13 months
- Cuspid 16—22 months
- First Molar 13—19 months
- Second Molar 25—3 3 months
- Mandibular Arch (Lower teeth)
- Central Incisor 6—10 months
- Lateral Incisor 10—16 months
- Cuspid 17—23 months
- First Molar 14—18 months
- Second Molar 23—31 months