Wisdom teeth, technically known as third molars, are the last teeth to emerge in the mouth, usually appearing long after all other permanent teeth have erupted. A common source of confusion is whether they continue to grow into adulthood. The simple answer is no; they do not “keep growing” continuously throughout adult life like hair or fingernails do. Sensations that feel like growth are actually related to the process of eruption or mechanical movement within the jawbone. This distinction between biological growth and physical movement is key to understanding the activity of third molars.
The Normal Development Timeline
The developmental growth of the third molars begins years before they become visible in the mouth. Initial calcification, where the tooth bud starts to form deep within the jawbone, often occurs around the age of 7 to 10.
The crown is typically completed between the ages of 12 and 16, but the root structure continues to develop for several more years. Growth involves the formation of the root and the hardening of the tooth structure. Eruption, or emergence through the gums, most commonly takes place between the ages of 17 and 25. Once the root is fully formed and the tooth reaches its functional position, the biological growth process ceases.
Post-Eruption Movement and Shifting
The sensation that a wisdom tooth is still moving late in life is a response to physical forces, not biological growth. Teeth are not rigidly fixed in the jawbone; they are suspended by the periodontal ligament, which allows for slight movement. This movement is distinct from the initial developmental growth phase.
One cause of perceived change is the slight migration of teeth within the jawbone, often in a forward direction. This compensates for the normal wear on the chewing surfaces. This phenomenon is termed mesial drift and affects all teeth. Pressure from chewing and biting can also cause subtle positional changes.
Another common source of discomfort that mimics growth is inflammation of the surrounding gum tissue, known as pericoronitis. This condition occurs when a wisdom tooth has only partially erupted, creating a flap of gum tissue where food debris and bacteria can become trapped. The resulting swelling and pain can feel like the tooth is forcefully pushing against adjacent structures.
Why Impaction Causes Problems
Impaction occurs when there is insufficient space for the third molars to fully erupt into a functional position. An impacted tooth remains partially or completely trapped within the jawbone or soft tissue. This lack of space frequently brings the tooth to a person’s attention through pain and swelling.
The orientation of an impacted tooth determines the type of problem that results. A mesial impaction, where the tooth is angled forward, is the most common and causes pressure on the adjacent second molar. A horizontal impaction, where the tooth lies completely on its side, can lead to the resorption of the neighboring tooth’s root.
Symptoms of impaction include pain that may radiate across the jaw, swelling or redness in the gums, and difficulty opening the mouth fully. Impacted teeth are prone to decay because their awkward position makes them difficult to clean, leading to the accumulation of bacteria and a higher risk of infection. Early assessment by a dental professional is recommended to monitor the development and angulation of these third molars.