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Title Coronectomy of 3rd Molars is Associated with Less Inferior Alveolar Nerve Damage Than Complete Tooth Extraction, When Potential Nerve Complications are Present
Clinical Question In clinical cases of potential inferior alveolar nerve involvement with 3rd molar extraction, is coronectomy or complete tooth extraction less likely to cause nerve damage?
Clinical Bottom Line Coronectomy allows for less root movement during extraction procedures, reducing the risk of mechanical damage to the inferior alveolar nerve, as compared to complete tooth removal.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 22622663Long/2012460 pts that had Coronectomy; 480 pts with whole tooth removedSystematic Review
Key resultsFor this systematic review, 37 studies were found in the literature, however only four studies qualified for the inclusion criteria established for this study. Two randomized control trials and two non-randomized control trials. Results showed that complete tooth removal is nearly 10 times more likely to have nerve injury compared to coronectomy. The post-op infection rates were equal for both procedures. However, coronectomy procedures reduced 1-week post-op pain in comparison to complete tooth extraction. Failed coronectomies in one study were found to be higher than normal, they correlated the 10% increase to narrowing roots and vertically impacted teeth. Root migration was reported to be high (13%-85%) in cases, but they were short distances of 3.06mm ± 1.67mm.
#2) 22467696Monaco/201243 coronectomies in 37 ptsRetrospective Case Study
Key resultsBased on the results of this study, coronectomy is a safe option for patients. 40 years and older with 3rd molars that cortical bone in the mandibular canal and/or direct contact between the root and the IA nerve. Removal of the crown allows for an average of 2 mm root migration into the open socket prior to new bone formation, allowing safer removal of roots if needed. Compared to complete extraction, coronectomy decreases the patient’s pain 1-week post-op. Periodontal resolution distal to 2nd molars occurred due to bone formation and gingival reduction.
#3) 15573343Pogrel/200450 coronectomies in 41 ptsProspective Case series
Key resultsSelection criteria for potential coronectomies are directly related to their success rate, no active infection or mobility may be present. One case resulted in transient lingual nerve involvement, due to the use of a lingual retractor. One patient required both lower 3rd molar roots to be removed because of failure for the sites to heal. Lastly, one case required removal of the root due to migration of the root to the surface. In conclusion, the study found that root migration post-op is unpredictable, but in all cases move to a safer position relative to the nerve. Also, studies have found that exposed pulp does not require treatment as long as the extraction site heals and bone formation occurs over the coronal portion of the root tip.
Evidence Search “Coronectomy Third Molar”
Comments on
The Evidence
Inferior Alveolar nerve damage can be detrimental and can impact negatively patient’s quality of life. Monaco et.al. (2012) and Pogrel et.al. (2004) developed a procedural protocol to avoid compressing the nerve that was very effective in their studies. This protocol emphasizes selection of sites, a critical step; non-horizontal orientated teeth and non-infected. Due to the reason that the root is being preserved in the alveolus, the absence of infection is required to allow proper healing and closure of the surgical area. Root migration away from the nerve was reported, making it safer for re-entry and removal. In addition, Long et.al. (2012) systematic review, reported also that the safety and effectiveness of Coronectomies to the patient is a viable option when nerve damage and postoperative pain is in consideration. Only those studies that compared coronectomies to third molar extractions, that were able to stand up to the Cochrane Reviewers’ Handbook were included in their meta-analysis. For this reason their selection of 38 studies were reduced to four. Long et.al. also reported that there was a higher failure rate of coronectomies when vertical impactions and narrowing roots were involved, making case selection critically important. Monaco et.al. (2012) nor Pogrel et.al. (2004) did not indicate if their surgeon was involved in case selection or not, making the determination of either bias or blinded study unable to be made. However, they did reference various other randomized studies that demonstrated positive results from coronectomies. Pogrel et.al. (2004) did state that using periapical and panoramic film made it difficult to determine the risk involved for the patient. Both authors agreed that coronectomy treatment is a decision to be made between the patient and the surgeon on an individual basis. All studies included powerful sample sizes and appropriate statistical analysis to demonstrate excellent levels of evidence; however, no Conchrane Reviews were found on this topic. Perspective: Coronectomy of third molars, where the potential for Inferior Alveolar Nerve injury is high, is a viable, less invasive alternative than complete tooth extractions and should be considered as a treatment option offered to patients.
Applicability Pericoronitis and other complications require the extraction of 3rd molars. When the roots of the 3rd molars are adjacent to the mandibular canal or adjacent to the Inferior Alveolar nerve, during surgery, damage may occur to the nerve. Whole tooth extractions are 10 times more likely to cause nerve damage compared to coronectomies. Coronectomy is a viable option to avoid nerve compression while performing an extraction. Post operative, the coronectomy reports to have less pain as compared to whole tooth extractions.
Specialty/Discipline (Oral Surgery)
Keywords dentistry, coronectomy, third molars, Inferior Alveolar nerve, nerve complication, Mandibular canal, Inferior Alveolar compression. J Dent Res. 2012;91:659-665.
ID# 2596
Date of submission: 10/31/2013spacer
E-mail andrew.newman@ucdenver.edu
Author Andrew Newman
Co-author(s) e-mail
Faculty mentor/Co-author Deise Oliveira, DDS & James Closmann, DDS
Faculty mentor/Co-author e-mail deise.oliveira@ucdenver.edu, James.closmann@ucdenver.edu
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