When I was quite a bit younger, my orthodontist showed me on X-rays of my jaw that I will only have two wisdom teeth (lower jaw). The one has recently started appearing above the gum. At what point can I tell if it is impacted? It has not been too painful.
– Dina*

The only way to really know if a wisdom tooth that is partially through the gum is impacted is to see a dentist or an oral surgeon for an X-ray.

Wisdom teeth often can't grow in normally. When they are impacted, it means the teeth either become stuck under the gum or are only able to partially break through the gum. Wisdom teeth usually become impacted because the jaw doesn't have enough space for all the teeth that are growing in, or because the tooth comes in at the wrong angle and bumps into the tooth in front of it.

Although some people never have any trouble with them, impacted wisdom teeth can cause problems. An impacted wisdom tooth can sometimes trap food, plaque, and other debris in the soft tissue around it, leading to swelling, gum tenderness, cavities, and bad breath.

You should see your dentist or oral surgeon to find out if your tooth is impacted. Dentists or oral surgeons often remove impacted wisdom teeth because they may damage other teeth or cause pain or infection.

*Names have been changed to protect user privacy.