A wisdom tooth growing sideways is almost always an impacted tooth, meaning it has not erupted fully into the mouth and is angled so that its crown points toward the neighboring molar rather than straight up through the gum. Dentists call this a horizontal impaction, and while it is not the single most common impaction angle, it is one of the most likely to cause problems for the tooth next door. The good news is that sideways wisdom teeth are well understood, readily diagnosed on a routine X-ray, and treatable with several approaches depending on your specific anatomy.
What “Sideways” Actually Means on an X-Ray
When your dentist says a wisdom tooth is sideways, they are usually describing its angle relative to the jawbone and the adjacent second molar. The classification most oral surgeons use, called Winter’s classification, sorts impacted wisdom teeth by the direction their crowns point. A tooth tilted forward toward the front of the mouth at a moderate angle is mesioangular. One lying flat on its side, parallel to the jawline, is horizontal. A tooth angled backward is distoangular, and one flipped completely upside down is inverted. “Sideways” in everyday language usually maps to horizontal, though some people use it loosely for a steeply mesioangular tooth as well.
Large radiographic studies consistently find that mesioangular impactions are the most common orientation, making up roughly half or more of all impacted lower wisdom teeth. Horizontal impactions are less common but far from rare. In one study of a Syrian population, horizontal impactions accounted for about a third of all mandibular third molar impactions, while mesioangular impactions were found in over half the cases.1PubMed Central. Association between mandibular third molar impaction patterns, second molar caries, and pericoronitis: a cross-sectional study in a syrian population A Saudi cohort showed a similar pattern, with mesioangular impactions most frequent on both sides, followed by vertical, horizontal, and distoangular orientations.2PubMed Central. Characterization of mandibular third molar impaction patterns and a CBCT-derived radiographic extraction difficulty in a Saudi cohort: A retrospective cross-sectional study Meanwhile, truly inverted teeth are extremely rare. A study of an East Baltic population found only seven inverted impactions out of thousands examined.3PubMed Central. The Pattern of Mandibular Third Molar Impaction and Assessment of Surgery Difficulty: A Retrospective Study of Radiographs in East Baltic Population
Beyond angulation, dentists also look at how deep the tooth sits relative to the biting surface of the molar in front of it and how much of the tooth is buried in the jawbone versus the ramus (the upward branch of the lower jaw). A sideways tooth buried deep and wedged against the second molar is a very different surgical proposition than one lying just under the gum line. These depth and position details are what your surgeon uses to estimate how complex the extraction will be.
Why a Sideways Tooth Threatens the One Next to It
The biggest practical worry with a horizontally impacted wisdom tooth is what it does to the second molar directly in front of it. Because the crown of the sideways tooth presses against the back surface of that second molar, it creates a pocket where food and bacteria accumulate in a spot that is nearly impossible to clean with a toothbrush or floss. Over time, this can cause decay on the distal (back) surface of the second molar. An expert consensus statement notes that impacted third molars significantly increase the risk of periodontitis, dental caries, and external root resorption of adjacent second molars.4PubMed Central. Expert consensus on the management of third molar health
The angulation of the wisdom tooth matters for this risk. Mesioangular and horizontal impactions carry the highest rates of second molar decay. One study found that mesioangular impactions were associated with second molar cavities in about 28% of cases, and horizontal impactions in about 22%, both considerably higher than other angulations.5PubMed Central. Exploring the Interplay of the Impaction Type of the Mandibular Third Molar With Second Molar Distal Surface Caries Depth also plays a role: teeth at an intermediate depth had a higher prevalence of second molar caries than those sitting very deep or very shallow. The clinical takeaway is that a sideways wisdom tooth is not just a cosmetic or comfort issue; it can silently destroy the tooth in front of it if left unchecked.
Pericoronitis and Recurring Infections
If your sideways wisdom tooth is partially poking through the gum, you are at risk for pericoronitis, an infection of the soft tissue flap (called an operculum) that covers the partially erupted crown. Pericoronitis tends to announce itself with throbbing pain around the back of your jaw, swelling, difficulty opening your mouth, and sometimes a foul taste from pus draining near the tooth. The flap of gum over a partially erupted tooth traps food and bacteria in a warm, moist environment that is ideal for infection.
Microbiological studies of pericoronitis show that the infection is driven by a mix of bacteria, with anaerobic species (bacteria that thrive without oxygen) found in nearly all cases.6PubMed Central. Evaluation of the mandibular third molar pericoronitis flora and its susceptibility to different antibiotics prescribed in france This matters because it explains why pericoronitis can become quite aggressive and why antibiotics alone, without ultimately removing the source of the problem, tend to provide only temporary relief. If you have had one episode, recurrence is common as long as the tooth remains partially erupted.
Most episodes of pericoronitis respond to warm saltwater rinses, careful cleaning of the area, and a short course of antibiotics if the infection is spreading. But repeated infections are a strong indication that the tooth needs to come out, because each episode risks spreading infection deeper into the tissues of the neck and jaw.
Cysts and Other Lesions
A less common but more serious risk of leaving a deeply impacted sideways tooth alone is the development of a dentigerous cyst, a fluid-filled sac that forms around the crown of an unerupted tooth. These cysts are the second most common type of jaw cyst, accounting for roughly 16% to 24% of all true jaw cysts, and they show up most often around lower wisdom teeth. The rate in the general population has been estimated at about 1.44 cysts per 100 unerupted teeth, with the majority occurring in young adults.7PubMed Central. Jaw lesions associated with impacted tooth: A radiographic diagnostic guide
Most dentigerous cysts grow slowly and painlessly, which is why they are sometimes discovered only when a panoramic X-ray is taken for another reason. Left untreated, though, they can expand enough to weaken the jawbone and displace neighboring teeth. In a study examining wisdom teeth associated with severe deep neck infections, the presence of a dentigerous cyst around the tooth was one of the strongest predictors of a dangerous infection spreading into the neck.8PubMed Central. The Radiographic Characteristics of Mandibular Wisdom Teeth That Can Cause Severe Deep Neck Infection That is an extreme outcome, but it underscores why your dentist monitors impacted teeth with periodic X-rays even when they are not hurting.
When Extraction Is Recommended
Not every sideways wisdom tooth needs to come out immediately. Clinical guidelines published by agencies like the UK’s National Institute for Health and Care Excellence (NICE) and the Scottish Intercollegiate Guidelines Network (SIGN) have discouraged purely prophylactic extraction of wisdom teeth that show no signs of disease.9PubMed Central. Review of clinical practice guidelines on the diagnosis and treatment of third molars. Evaluation of adherence to AGREE II publication guideline A Cochrane review on the topic concluded that the evidence is insufficient to determine definitively whether asymptomatic, disease-free impacted wisdom teeth should be removed or retained, noting only very low-certainty evidence that their presence may increase long-term periodontitis risk around the adjacent molar.10PubMed Central. Surgical removal versus retention for the management of asymptomatic disease-free impacted wisdom teeth
However, “asymptomatic and disease-free” is a high bar that many sideways teeth fail to meet over time. Clear reasons to extract include:
- Recurring pericoronitis: repeated bouts of infection around the gum flap.
- Decay: cavities forming on the wisdom tooth itself or the back surface of the adjacent molar.
- Cyst formation: a widening radiolucent area around the crown on X-ray.
- Root resorption: the wisdom tooth pressing hard enough to dissolve part of the neighboring tooth’s root.
- Periodontal pocketing: deep gum pockets behind the second molar that cannot be managed with regular cleaning.
The shift away from routine prophylactic extraction had an unintended side effect in the UK. After NICE’s guidelines were implemented, the average age of patients coming in for wisdom tooth surgery rose from about 25 to 32, and surgeons ended up treating more teeth that already had associated pathology. That made the surgeries harder and more expensive for the health system as a whole. This experience illustrates the tension in the field: removing every asymptomatic wisdom tooth is probably overkill, but waiting until disease develops can make treatment more complicated.
Nerve Risks During Removal
One of the main reasons sideways wisdom teeth attract extra surgical caution is their proximity to the inferior alveolar nerve (IAN), which runs through a canal in the lower jaw and supplies sensation to your lower lip and chin. A horizontally impacted tooth can sit right on top of this canal, and extracting it carries a risk of bruising, stretching, or in rare cases cutting the nerve. A literature review found that the reported incidence of IAN injury after lower wisdom tooth extraction ranges from about 0.35% to 8.4%, with higher risk for horizontal impactions, patients over 24, and less experienced surgeons.11PubMed Central. Inferior alveolar nerve injury after mandibular third molar extraction: a literature review
Advanced imaging with cone-beam CT (CBCT) scans can help predict this risk before surgery. When the nerve canal is in direct contact with the tooth roots, the risk goes up substantially. In one cohort where CBCT imaging confirmed root-nerve contact, the overall rate of IAN injury was about 13%, and specific features on the scan, such as the canal being flattened or sitting on the tongue side of the roots, were identified as independent predictors of nerve damage.12PubMed Central. Radiographic features of anatomic relationship between impacted third molar and inferior alveolar canal on coronal CBCT images: risk factors for nerve injury after tooth extraction Most nerve injuries are temporary and resolve within weeks to months, but persistent numbness or tingling can occasionally last longer.
Coronectomy as an Alternative
When imaging shows that the roots of a sideways wisdom tooth are wrapped around or pressed tightly against the nerve canal, your surgeon may suggest a coronectomy instead of a full extraction. In a coronectomy, the crown of the tooth is removed but the roots are deliberately left in the jawbone. The idea is to eliminate the part of the tooth causing problems (the crown, which traps bacteria and presses on the adjacent molar) while leaving the roots undisturbed so the nerve is not injured.
A systematic review concluded that coronectomy can be considered a low-risk procedure and a valid option for protecting nerve structures. Over time, the retained roots often migrate away from the nerve canal, which means that if they ever do need to be removed later, the second procedure carries a lower risk of nerve injury than the original extraction would have.13PubMed Central. Does the Coronectomy a Feasible and Safe Procedure to Avoid the Inferior Aveloral Nerve Injury during Third Molars Extractions? A Systematic Review A comparative study found that coronectomy patients had significantly shorter pain duration and markedly lower rates of both numbness and swelling compared to those who had a full extraction.14Journal of Bahria University Medical and Dental College. Comparison of Coronectomy and complete extraction for impacted Third Molars in Close Proximity to Inferior Alveolar Nerve
Coronectomy is not appropriate for every situation. If the tooth is infected, for instance, leaving root fragments behind could perpetuate the infection. And not every retained root stays quiet; a small percentage of patients need a second surgery to remove roots that later become symptomatic or start migrating toward the surface. Still, for the specific scenario of a sideways tooth with roots hugging the nerve, it offers a meaningful safety advantage.
What the Extraction Itself Involves
Removing a horizontally impacted wisdom tooth is more involved than pulling a normally erupted tooth. The surgeon typically needs to make an incision in the gum, remove a small amount of bone covering the tooth, and then section the tooth into pieces small enough to lift out without excessive force. For horizontally impacted teeth specifically, newer crown-sectioning techniques have been shown to reduce the amount of bone removed, shorten operation time, and decrease postoperative pain and jaw stiffness compared to older approaches.15PubMed Central. Application of the “半” shaped crown sectioning method in minimally invasive extraction of mandibular horizontally impacted teeth
Most sideways wisdom tooth extractions are done under local anesthesia, sometimes combined with intravenous sedation. A study comparing sedation plus local anesthesia to local anesthesia alone found that patients who received sedation reported significantly lower pain scores during the procedure and much higher satisfaction afterward.16PubMed. Evaluation of the effect of conscious sedation on patient satisfaction and pain after wisdom tooth extraction If anxiety is a major concern for you, discussing sedation options with your surgeon beforehand is worthwhile.
Recovery and Dry Socket
The first few days after extraction tend to be the roughest. A systematic review of quality-of-life outcomes found that wisdom tooth removal has a clear negative effect on daily life during the initial postoperative period, but symptoms improve progressively when patients follow their surgeon’s aftercare instructions.17PubMed Central. Quality of life after extraction of mandibular wisdom teeth: A systematic review Pain scores are typically highest on the first day and drop substantially by the end of the first week.18PubMed Central. Oral Health-related quality of life after coronectomy for impacted mandibular third molar in the first postoperative week
The complication people worry about most is alveolar osteitis, better known as dry socket. This happens when the blood clot that normally forms in the extraction site breaks down or is dislodged, leaving exposed bone. It causes severe, radiating pain that usually starts one to three days after the procedure. For routine extractions, the rate is about 1% to 5%, but it can reach as high as 20% after surgical removal of impacted lower wisdom teeth.19PubMed Central. The Effect of Platelet-Rich Fibrin in Preventing Alveolar Osteitis Following Mandibular Third Molar Surgery: A Systematic Review and Meta-Analysis Smoking, drinking through a straw, and vigorous rinsing in the first day or two all increase the risk by disrupting the clot.
For women taking oral contraceptives, there is an additional risk factor worth knowing. A study found that women who continued taking oral contraceptives around the time of extraction had a dry socket rate of about 7.5%, compared to roughly 2.2% in those who discontinued them before surgery.20PubMed Central. Influence of oral contraceptive/low-dose estrogen progestin discontinuation on the incidence of alveolar osteitis after third molar extraction: a retrospective study at a single center Estrogen and progestin affect the body’s clotting and fibrinolytic systems, which is likely why the clot in the socket is more vulnerable. If you are on hormonal contraception, it is worth raising this with your surgeon to discuss timing.
Platelet-Rich Fibrin and Healing Aids
Some surgeons now use platelet-rich fibrin (PRF), a concentrate prepared from your own blood, to pack the extraction socket. The idea is to give the healing site a concentrated dose of growth factors. A meta-analysis found that PRF application reduced the incidence of dry socket by about 67% compared to normal healing.19PubMed Central. The Effect of Platelet-Rich Fibrin in Preventing Alveolar Osteitis Following Mandibular Third Molar Surgery: A Systematic Review and Meta-Analysis A systematic review of extraction socket healing more broadly found that PRF significantly reduced pain in the first one to three days, improved soft tissue healing at the one-week mark, and reduced bone loss in the socket over the first couple of months.21PubMed Central. Efficacy of platelet-rich fibrin in promoting the healing of extraction sockets: a systematic review
A randomized controlled trial using three-dimensional face scans confirmed that the PRF side of the jaw had significantly less swelling by day 14 and that patients needed fewer painkillers on that side.22PubMed Central. Effectiveness of platelet-rich fibrin in third molar extractions: a randomized controlled split-mouth study PRF is not yet standard everywhere, and it does require a blood draw before your procedure, but it is increasingly available and worth asking about if you are having a complex extraction.
Why Age Matters
If you are in your late teens or early twenties, you have an advantage: the roots of your wisdom teeth are not fully formed yet, the surrounding bone is less dense, and your body heals faster. Research confirms that as patient age increases, so does the duration of surgery, the rate of postoperative complications like dry socket, trismus (difficulty opening the mouth), and swelling, and the negative impact on quality of life during recovery.23PubMed Central. Evaluation of complications and quality of life of patient after surgical extraction of mandibular impacted third molar teeth
This does not mean older adults should avoid extraction if they need it, but it explains why surgeons sometimes recommend removing a sideways wisdom tooth in your twenties rather than waiting until problems develop in your thirties or later. The UK’s experience after restricting prophylactic extractions is illustrative: the average age of wisdom tooth patients rose by about seven years, and those older patients had more complicated cases with higher costs. For a tooth that your dentist expects will eventually cause trouble based on its position and trajectory, earlier removal is generally easier on you and carries a lower complication rate.
The “Watch and Wait” Approach
If your sideways wisdom tooth is fully buried in bone, not pressing on the neighboring tooth, not associated with a cyst, and not causing infections, your dentist may recommend monitoring rather than immediate surgery. This means periodic X-rays, typically every year or two, to watch for changes in the tooth’s position, the development of a cyst, or signs of decay on the adjacent molar. The Cochrane review’s conclusion that evidence is insufficient to recommend universal extraction of disease-free impacted teeth supports this wait-and-see strategy for genuinely asymptomatic cases.
The risk of monitoring is that problems can develop silently. A cavity on the back of your second molar or a slowly growing cyst will not necessarily hurt until significant damage is done. That is why the X-ray follow-ups are essential. If you choose to monitor, skipping those checkups defeats the purpose. The conversation with your dentist should not be “extract or ignore” but “extract now or watch carefully and extract if things change.”
Can a Sideways Wisdom Tooth Cause Crowding of Your Front Teeth?
This is one of the most persistent beliefs in dentistry, and the evidence does not support it well. Many people assume that a sideways wisdom tooth pushing forward will eventually crowd or shift the lower front teeth. Research looking at the relationship between lower wisdom teeth and anterior crowding has found that while crowding is associated with less available space for the third molar, the angulation of the wisdom tooth itself does not significantly differ between people with and without crowding.24Journal of Health and Allied Sciences NU. Lower Third Molar Space and Angulation in Individuals with Lower Anterior Crowding Lower front teeth tend to shift slightly forward with age regardless of whether wisdom teeth are present. Removing wisdom teeth to prevent this crowding has not been shown to make a meaningful difference, and orthodontists increasingly recognize that late crowding is driven by other factors like jaw growth patterns and the natural forward pressure of the dental arch over time.