Tooth eruption is a natural developmental process where a tooth emerges into the mouth. It involves the movement of the tooth from its initial position within the jawbone until it becomes visible in the oral cavity. This complex biological action is orchestrated by various cellular mechanisms, including bone remodeling that creates a path for the tooth.
Understanding Full Eruption
A tooth is considered fully erupted when it has moved through the gum line and reached its final, stable position in the mouth. This position allows it to properly meet its opposing tooth in the other jaw, a process known as occlusion.
There is a distinction between anatomical eruption and clinical eruption. Anatomical eruption refers to the tooth’s crown being fully exposed, while clinical eruption describes when the tooth becomes visible in the mouth and functional.
Typical Eruption Schedules
Teeth emerge following a general timeline. Primary, or “baby,” teeth begin to appear around 6 months of age, starting with the lower central incisors. By 2.5 to 3 years old, most children will have all 20 of their primary teeth. These teeth are placeholders for the larger permanent teeth that will follow.
Permanent teeth start to replace primary teeth around age 6, beginning with the first permanent molars and lower incisors. This period, known as mixed dentition, involves both primary and permanent teeth coexisting. Individuals will have all 28 permanent teeth, excluding wisdom teeth, by age 12 or 13. Wisdom teeth, the third molars, are the last to erupt, appearing between ages 17 and 25.
When Teeth Don’t Fully Erupt
Sometimes, a tooth does not fully emerge into its proper position, leading to various issues. This can happen if a tooth becomes impacted, meaning it is unable to break through the gum or jawbone due to obstruction, crowding, or growing in the wrong direction. Wisdom teeth are affected by impaction because there may not be enough space in the jaw for them to fully erupt.
A partially erupted tooth can create a space where food particles and bacteria become trapped. This can lead to localized infections, such as pericoronitis, and increase the risk of tooth decay and gum disease for both the partially erupted tooth and adjacent teeth. Non-full eruption can also cause pain, swelling, misalignment of other teeth, and the formation of cysts or damage to nerves.