Question explored with the scientific record
How is an impacted wisdom tooth growing sideways removed
The short version: for a horizontally impacted wisdom tooth, the evidence supports surgical extraction with CBCT imaging to map nerve risk, and the real question is whether you need the surgery at all.
The evidence here is almost entirely about how to extract, not whether to extract. One large retrospective study of 2650 mandibular third molars found that horizontal impactions had a 2% rate of dental lesions and 17% rate of periodontal lesions in the third molar itself, but the real damage was to the adjacent second molar: 12% dental and 17% periodontal lesions on the distal surface [1]. That is a real risk, but it is not an emergency. The most common reason people get these out is recurrent pericoronitis (inflammation around the crown), accounting for 34% of surgeries in a 1198-case series [16]. Caries and pulpitis were the second reason at 25% [16]. Prophylactic removal—taking it out before it causes trouble—was only 5% of cases [16].
The surgical risk worth knowing is nerve injury. A prospective study of 60 sockets found that panoramic X-rays miss about a third of nerve exposures that CBCT catches: panoramic sensitivity was 68% versus 97% for CBCT [21]. The nerve injury rate in a 423-extraction study was 1.2% overall, and all five injuries occurred in patients 25 or older [11]. A coronectomy—cutting off the crown and leaving the root—is an alternative when the nerve is at high risk. A 2023 review of 1643 patients found IAN sensory disturbance rates between 1.6% and 4.3% after coronectomy, with infection rates from 3% to 14% and dry socket from 2% to 15% [19]. One retrospective series of 68 coronectomy patients reported a 1.5% rate of permanent nerve injury and a 13% rate of postoperative infection, with 2 of 68 requiring reoperation [20].
| Risk or outcome | Full extraction | Coronectomy (high-risk cases) |
|---|---|---|
| Permanent IAN nerve injury | ~1.2% overall [11] | ~1.5% [20] |
| Postoperative infection | Not reported in these studies | 3–14% across studies [19, 20] |
| Dry socket | Not reported in these studies | 2–15% across studies [19] |
| Root migration (coronectomy only) | N/A | 62–100% at 12 months [19, 20] |
My call: if you have recurrent pain or infection, extraction is reasonable, and CBCT imaging is worth the extra radiation to map the nerve. If you have no symptoms, the evidence does not show a clear benefit to prophylactic removal—the 5% rate of prophylactic surgery in the large case series [16] suggests most surgeons do not push for it either. Confidence: moderate. The evidence on extraction technique is solid; the evidence on whether to extract at all is thin and observational.
Sources examined 21
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The association of mandibular third molar impaction with the dental and periodontal lesions in the adjacent second molars
A retrospective panoramic radiograph study of 1826 radiographs (2650 mandibular third molars) from a Guangzhou hospital assesses dental and periodontal lesions in the third molars and distal surfaces of adjacent second molars across impaction types, finding higher lesion prevale…
DOI: 10.1002/jper.20-0424 -
External Root Resorption of the Second Molar Associated With Third Molar Impaction: Comparison of Panoramic Radiography and Cone Beam Computed Tomography
CBCT detects significantly more external root resorption in second molars adjacent to impacted third molars than panoramic radiography, especially for mesioangular or horizontal impactions, supporting CBCT for accurate diagnosis and potential management decisions such as prophyl…
DOI: 10.1016/j.joms.2014.03.023 -
Efficacy of Submucosal Injection of Chymotrypsin, Oral Serratiopeptidase or Oral Dexamethasone in Reducing Postoperative Complications Following Impacted Lower Third Molar Surgery: A Prospective, Randomized, Double-Blind, Controlled Clinical Trial
In a randomized, three-arm, double-blind clinical trial, submucosal chymotrypsin, oral serratiopeptidase, and oral dexamethasone were compared for reducing postoperative pain, swelling, and trismus after surgical extraction of impacted mandibular third molars, with no significan…
DOI: 10.3389/froh.2020.575176 -
Comparison of cone-beam volumetric imaging and combined plain radiographs for localization of the mandibular canal before removal of impacted lower third molars
This study compares the diagnostic value of cone-beam volumetric imaging (CBVI) with conventional panoramic and PA cephalometric radiographs for accurately locating the mandibular canal prior to the surgical removal of impacted lower third molars, finding that CBVI significantly…
DOI: 10.1016/j.tripleo.2007.08.041 -
Evaluating the risk of post-extraction inferior alveolar nerve injury through the relative position of the lower third molar root and inferior alveolar canal
A retrospective CBCT-based study classifying the relative position of lower third molar roots to the inferior alveolar canal to assess risk of post-extraction inferior alveolar nerve injury, finding the AE (adjacent to enlarged root) configuration as the strongest predictor and …
DOI: 10.1016/j.ijom.2019.07.008 -
Surgical Removal of the Fully Impacted Mandibular Third Molar: The Influence of Flap Design and Alveolar Bone Height on the Periodontal Status of the Second Molar
This study investigates the impact of surgical removal of fully impacted mandibular third molars on the periodontal status of the second molars, finding significant attachment loss regardless of flap design or initial alveolar bone height.
DOI: 10.1902/jop.1985.56.10.625 -
Does Topical Ozone Therapy Improve Patient Comfort After Surgical Removal of Impacted Mandibular Third Molar? A Randomized Controlled Trial
This randomized controlled trial investigates the efficacy of topical ozone therapy in improving patient comfort, specifically post-operative pain, swelling, and mouth opening, after the surgical removal of impacted mandibular third molars compared to systemic antibiotics.
DOI: 10.1016/j.joms.2016.09.014 -
The efficacy of curcumin in managing acute inflammation pain on the post‐surgical removal of impacted third molars patients: A randomised controlled trial
This randomized controlled trial investigates the efficacy of curcumin in managing acute inflammation pain following the surgical removal of impacted third molars, demonstrating that curcumin significantly reduces pain compared to standard analgesics.
DOI: 10.1111/joor.12679 -
Use of Therapeutic Laser After Surgical Removal of Impacted Lower Third Molars
A double-blind randomized trial evaluating an 810 nm diode laser (4 J/cm2) applied intra- and extraorally after surgical removal of impacted lower third molars found no statistically significant reductions in postoperative pain, swelling, or trismus compared with standard care, …
DOI: 10.1016/j.joms.2009.07.037 -
Surgical removal of the pregastric pouch does not affect voluntary ethanol consumption in golden hamsters
This study investigates the impact of surgical removal of the pregastric pouch on voluntary ethanol consumption in golden hamsters, finding no significant effect on their ethanol intake.
DOI: 10.1016/0031-9384(95)00020-j -
Self-assessed neurological disturbances after surgical removal of impacted lower third molar: a pragmatic prospective study on 423 surgical extractions in 247 consecutive patients
This study investigates the incidence of self-assessed neurological disturbances following the surgical removal of impacted lower third molars, finding a low overall incidence of transient lip sensitivity impairment associated with radiographic risk indicators in patients aged 2…
DOI: 10.1007/s00784-018-2747-9 -
Bilateral surgical removal of impacted mandibular third molar teeth as a model for drug evaluation: A test with oxyphenbutazone (Tanderil®)
This study evaluates the efficacy of oxyphenbutazone in reducing postoperative pain and swelling following the bilateral surgical removal of impacted mandibular third molars in a double-blind crossover trial involving 24 healthy patients.
DOI: 10.1016/s0300-9785(77)80051-3 -
Clinical postoperative findings after removal of impacted mandibular third molars: prediction of postoperative facial swelling and pain based on preoperative variables
This study investigates the relationship between preoperative variables and short-term postoperative outcomes, specifically facial swelling and pain, in patients undergoing the surgical removal of impacted mandibular third molars.
DOI: 10.1016/j.bjoms.2004.02.005 -
Use of ibuprofen and methylprednisolone for the prevention of pain and swelling after removal of impacted third molars
This study investigates the efficacy of a combination treatment of ibuprofen and methylprednisolone in reducing pain and swelling after the surgical removal of impacted third molars, demonstrating significant reductions in both compared to placebo.
DOI: 10.1016/0278-2391(95)90486-7 -
Submucosal injection of dexamethasone and methylprednisolone for the control of postoperative sequelae after third molar surgery: randomized controlled trial
This study compares the effects of preoperative submucosal administration of dexamethasone and methylprednisolone on postoperative pain, swelling, and trismus in patients undergoing the surgical removal of impacted mandibular third molars, finding dexamethasone to be more effect…
DOI: 10.1016/j.ijom.2017.07.009 -
Impacted Mandibular Third Molars: A Retrospective Study of 1198 Cases to Assess Indications for Surgical Removal, and Correlation with Age, Sex and Type of Impaction—A Single Institutional Experience
This retrospective study of 1198 cases investigates the incidence of impacted mandibular third molars, their correlation with age, sex, and type of impaction, and the indications for surgical removal, revealing a predominance of mesioangular impaction and recurrent pericoronitis…
DOI: 10.1007/s12663-016-0929-z -
Analgesic efficacy and tolerability of diflunisal in oral surgery
In a double-blind, randomized trial of 169 patients undergoing surgical removal of impacted third molars, diflunisal provided superior early analgesia and fewer adverse effects than the fixed-combination analgesic Veralgin, supporting NSAIDs as preferable for postoperative denta…
DOI: 10.1016/S0901-5027(87)80056-5 -
Position of the impacted third molar in relation to the mandibular canal. Diagnostic accuracy of cone beam computed tomography compared with panoramic radiography
This study evaluates the diagnostic accuracy of cone beam computed tomography (CBCT) compared to panoramic radiography in predicting inferior alveolar nerve (IAN) exposure during third molar surgery, finding no significant difference in sensitivity and specificity between the tw…
DOI: 10.1016/j.ijom.2009.06.007 -
INCIDENCE OF COMPLICATIONS AFTER THIRD MANDIBULAR MOLAR CORONECTOMY
Low neurosensory disturbance and modest infection/dry socket rates after coronectomy of mandibular third molars, suggesting a safer alternative to full extraction in high‑risk cases, though heterogeneity across studies prevents meta-analysis and calls for better‑designed trials.
DOI: 10.35988/sm-hs.2023.195 -
Coronectomy and dentigerous cysts: a review of 68 patients
Coronectomy with dentigerous cyst removal is an effective, low-morbidity option for teeth near the inferior alveolar nerve, as shown by a retrospective series of 68 patients (73 teeth) with one permanent IDN injury and notable root migration and infections in some cases.
DOI: 10.1016/j.oooo.2017.02.001 -
Diagnostic value of cone beam computed tomography and panoramic radiography in predicting mandibular nerve exposure during third molar surgery
A prospective clinical study comparing cone beam computed tomography (CBCT) and panoramic radiography for predicting inferior alveolar nerve exposure during third molar surgery, finds CBCT has higher diagnostic accuracy than panoramic radiography and identifies key radiographic …
DOI: 10.1016/j.ijom.2016.10.003