The twenty teeth that appear during childhood, known as deciduous or primary teeth, serve as temporary structures that hold space for the permanent adult set. The definitive answer is yes: in the vast majority of people, every single primary tooth is naturally shed. This process is a biological event necessary for the transition to the permanent dentition. Shedding begins as the permanent counterparts develop directly beneath the primary teeth, signaling the start of a multi-year transition period.
The Standard Timeline for Tooth Loss
The process of losing primary teeth typically commences around the age of six, marking the beginning of the mixed dentition phase. The front teeth are usually the first to be shed, starting with the lower central incisors, followed closely by the upper central incisors between the ages of six and seven. This initial phase is succeeded by the loss of the lateral incisors around age seven to eight.
The loss of the back teeth occurs later. The first molars shed between ages nine and eleven, and the canines between nine and twelve. The second molars are often the last primary teeth to be lost, typically around age ten to twelve, concluding the process by the early teenage years. During this time, the first permanent molars, often called the “six-year molars,” erupt into the mouth behind the existing baby teeth.
How Permanent Teeth Replace Baby Teeth
The mechanism by which primary teeth are lost is a natural physiological process called root resorption, which involves the breakdown of the tooth’s structure. As the permanent tooth develops and moves upward within the jawbone, it exerts pressure against the root of the overlying baby tooth. This pressure triggers the body’s cells to dissolve and absorb the primary tooth’s root structure and the surrounding bone.
As the root shortens, the primary tooth becomes increasingly mobile until it falls out, leaving a space for the permanent tooth to emerge. The complete adult set contains 32 teeth, compared to the 20 deciduous teeth. The permanent premolars replace the primary molars, while the additional permanent molars erupt into the expanding jaw at the back of the mouth.
When Baby Teeth Are Retained
While the system is designed for complete replacement, some baby teeth are retained into adulthood, failing to exfoliate naturally. The most frequent reason for this anomaly is the congenital absence of the permanent tooth successor beneath it, a condition termed hypodontia. Without the pressure from the developing permanent tooth, the root of the baby tooth never undergoes the resorption process.
Another cause is ankylosis, where the primary tooth root fuses directly to the jawbone, preventing its natural movement and loss. Misalignment of the permanent tooth, sometimes called ectopic eruption, can also cause retention, as the adult tooth may erupt at an incorrect angle, failing to make contact with the baby tooth root to initiate resorption. When a primary tooth is retained past its expected shedding time, a dental evaluation, typically involving X-rays, is necessary to determine the underlying cause and whether extraction or continued monitoring is appropriate.