A partial bony impaction is a specific type of wisdom tooth impaction in which the tooth has partially emerged through the gum but a portion of the crown (the top of the tooth) remains enclosed within the jawbone. This partial eruption creates a unique set of oral health challenges that often lead to a recommendation for extraction.
What Creates a Partial Bony Impaction?
When there is insufficient space in the jaw for a wisdom tooth to fully erupt — due to the size of the jaw, the angle of the tooth, or the presence of adjacent teeth — the tooth gets stuck mid-eruption. The crown partially breaks through the gum tissue but remains partly encased in bone. This creates an opening in the gum that communicates with the oral environment.
Why It's Problematic
The persistent opening in the gum tissue around the partially erupted crown creates a pathway for bacteria to accumulate in a space that cannot be cleaned with a toothbrush or floss. This leads to pericoronitis — inflammation and infection of the surrounding tissue — which causes pain, swelling, bad breath, and in some cases, spread of infection to adjacent spaces. The partial eruption also makes the tooth highly susceptible to decay on its exposed surface and on the distal surface of the adjacent second molar.
Treatment
In most cases, extraction is recommended. The surgical complexity of removing a partial bony impaction is greater than a simple extraction because the bone encasing part of the crown must be carefully removed to allow tooth delivery. This is why an oral surgeon with experience in complex extractions is typically the appropriate provider.
If you have been told you have a partially impacted wisdom tooth, a consultation with an oral and maxillofacial surgeon will provide you with a clear assessment of the best approach for your specific anatomy.