An impacted wisdom tooth is one that does not have enough room to emerge or develop normally. It may be stuck beneath the gum, growing at an angle, or pressing against the adjacent tooth. Impaction is extremely common — studies show that up to 70% of people have at least one impacted wisdom tooth.
The Four Types of Wisdom Tooth Impaction
Impacted wisdom teeth are classified based on the angle at which they are positioned. Your dentist identifies the type from an X-ray (OPG or CBCT scan).
1. Mesial Impaction (Most Common)
The wisdom tooth is angled forward, towards the front of the mouth, leaning into the second molar. This is the most common type, accounting for about 40 to 50% of all impactions. The tooth pushes against the tooth in front of it, which can cause pain, decay on the adjacent tooth, or crowding.
2. Vertical Impaction
The wisdom tooth is oriented in the correct upright position but is stuck beneath the gum or bone and cannot fully erupt because there is not enough space. This type may not always need extraction — if the tooth is positioned correctly and has a good chance of eventually erupting normally, your dentist may recommend monitoring it.
3. Horizontal Impaction
The wisdom tooth is lying completely on its side, parallel to the jawbone and perpendicular to the adjacent teeth. This is the most complex type of impaction and almost always requires surgical extraction. The tooth presses directly against the roots of the adjacent molar, which can cause pain and damage.
4. Distal Impaction (Least Common)
The wisdom tooth is angled backward, away from the adjacent tooth, towards the back of the mouth. This is the least common type. While it may cause fewer problems for the adjacent tooth, it can still lead to infections and difficulty cleaning.
Soft Tissue vs Bony Impaction
In addition to the angle, impacted wisdom teeth are classified by how deeply they are buried:
- Soft tissue impaction — The tooth has emerged through the bone but is still partially or fully covered by gum tissue. This is generally a simpler extraction.
- Partial bony impaction — The tooth is partially encased in the jawbone. Some bone needs to be removed during extraction.
- Full bony impaction — The tooth is completely encased in the jawbone. This requires the most involved surgical approach and is typically the most expensive.
Why Does the Type of Impaction Matter?
The type of wisdom tooth impaction determines the complexity of surgery, the duration of the procedure, the recovery time, and the overall cost. Horizontal and full bony impactions require more bone removal and take longer to extract than soft tissue or vertical impactions. Your dentist uses X-rays to classify the impaction and plan the safest approach.
The type and depth of impaction affects:
- Treatment complexity — Horizontal and full bony impactions are more complex surgeries
- Surgery duration — More complex impactions take longer (30 to 60 minutes vs 20 to 30 minutes)
- Cost — Ranges from $350 to $1,250 per tooth, all within Medisave limits
- recovery time — More complex extractions may have slightly longer recovery
- Risk of complications — Deeper impactions near the nerve carry a slightly higher (but still low) risk of temporary numbness
Good news: Regardless of the type of impaction, all surgical wisdom tooth surgerys are 100% Medisave claimable up to $1,250 per tooth at Trust Dental Surgery. The cost varies with complexity, but it is all covered.
How Do We Diagnose the Type of Impaction?
During your consultation, we take an OPG (panoramic X-ray) that shows all four wisdom teeth in a single image. This reveals the exact position, angle, depth, and proximity to the nerve. In complex cases involving the lower jaw nerve, we may recommend a CBCT (3D cone beam scan) for a more detailed view before surgery.
Should All Impacted Wisdom Teeth Be Removed?
Not all impacted wisdom teeth require removal, but most do. Extraction is recommended if the impacted tooth is causing pain, recurring infections, decay in the adjacent tooth, or cyst formation. Your dentist may recommend monitoring if the impaction is asymptomatic and not affecting nearby teeth, though regular X-ray reviews are advised.
Not necessarily, but most should. Removal is recommended if the impacted tooth is:
- Causing pain or recurring infections
- Damaging or decaying the adjacent tooth
- Associated with a cyst on X-ray
- Positioned in a way that makes future problems likely
Vertically impacted teeth that are not causing problems may be monitored with regular X-rays. However, most dentists agree that mesial and horizontal impactions should be removed, even if they are currently asymptomatic, because they are very likely to cause problems over time.
