October 2016 Orthodontics 141 Sophie Marshall Catherine Bryant Coronectomy: A Case Series Demonstrating its Value in Younger Patients Abstract: This article describes the value of coronectomy as an alternative to the removal of teeth in the management of younger patients when intervention is required but extraction is associated with a heightened risk of post-operative neuropathy. Three cases are presented of children who underwent a coronectomy procedure which was planned within a multidisciplinary Orthodontic, Oral Surgery and Paediatric Dentistry team at King’s College Hospital. None of the children experienced post-operative neuropathy. CPD/Clinical Relevance: This article describes the value of coronectomy (partial odontectomy) as an alternative to the removal of teeth in the management of younger patients when intervention is required but extraction is associated with a heightened risk of post-operative neuropathy. Ortho Update 2016; 9: 141–148 Coronectomy, or partial odontectomy, is a their patients presenting with symptomatic radiographs or cone beam computed conservative surgical technique in which the mandibular third molar teeth. Dysfunction of tomography (CBCT) suggest that the crown of a tooth is removed but its roots/ the IAN after third molar removal resulting in surgical removal of the entire tooth would root are deliberately left in situ. In carefully neuropathy (altered sensation, neuropathic present an increased risk of post-operative selected cases, this alternative to the pain or both) affecting the lower lip, chin, neuropathy as a result of disruption to the complete removal of a tooth may represent teeth or labial mucosa is uncommon but very IAN or its branches. This situation is seen the treatment of choice in a number of clinical distressing for many patients affected. In an most commonly in younger patients when scenarios. It is most frequently used to reduce increasingly litigious society, the desire to there is a degree of failure in the eruption the risk of post-operative neuropathy in the prevent unnecessary patient suffering and the of mandibular premolar or molar teeth, management of symptomatic mandibular medicolegal consequences of this has proved causing them to be retained in an unerupted third molar teeth (M3M) which are considered, to be a potent driver of a change in clinical or partially erupted position. If the follicle after the interpretation of available imaging, practice for many surgeons. Any dentist who of such a tooth communicates with the oral likely to be closely related to the inferior has found him/herself in the position of being cavity, caries or symptoms of pericoronitis alveolar nerve (IAN).1,2 There is a growing unable to complete a planned extraction and may result and necessitate surgical body of evidence that M3M coronectomy forced to leave the apical portion of a root in intervention. Alternatively, surgery may can reduce the incidence of post-operative situ will recognize that this rarely results in become necessary to prevent a malocclusion disturbance in the function of the IAN when any significant clinical complication. It is on worsening, treat cystic change associated compared to extraction of these teeth when a similar principle that the coronectomy of with an unerupted tooth or to address surgical intervention is unavoidable.2-6 healthy, vital teeth as an elective procedure the effects of resorption on adjacent teeth The concept of coronectomy has been advocated. from their unerupted counterparts. Case as a planned intervention is not new.7 Its The coronectomy of a non- selection is, however, critical. This technique use in third molar surgery has, in recent third molar tooth may be indicated when is not widely utilized for teeth other than years, received great attention from oral symptoms or pathology associated with third molars, although its application in the surgeons keen to improve the outcome for it dictate that it should be extracted but management infraoccluded mandibular Sophie Marshall, BSc(Hons), BDS(Hons), MFDS RCS(Ed), Specialty Registrar in Paediatric Dentistry, Department of Paediatric Dentistry and Catherine Bryant, BDS, MSc, FDS RCS, DipDSed, Consultant in Oral Surgery, Department of Oral Surgery, King’s College Dental Hospital, Bessemer Road, London SE5 9RS, UK. Downloaded from magonlinelibrary.com by Chris Lawton on January 2, 2020. 142 Orthodontics October 2016 first molars has been described.8 Successful sequelae and complications and to discuss extraction had been performed. It is essential coronectomy relies on the retained roots these pre-operatively with patients. The that acute, early post-operative symptoms are remaining vital and there being healthy mobilization of the root fragments during not incorrectly attributed to the presence of bony infill at the site previously occupied the removal of the coronal portion of the retained roots following coronectomy. These by the coronal portion of the tooth. Caries, tooth is the most frequently occurring should be left in situ and the risks associated apical pathology or pathological lesions, intra-operative complication. This is more with their removal avoided until the which cannot be completely excluded at the likely in single or short-rooted teeth and indications for root removal can be assessed time of coronectomy, and tooth mobility when the coronectomy cut is of inadequate more accurately after the (expected) acute are therefore contra-indications to this depth or width, which requires the surgeon sequelae of surgery have resolved. Healing treatment.9 Similarly, coronectomy should be to apply greater force to fracture off the can be delayed or fail to progress after avoided in patients with systemic conditions crown. If this problem is identified early, coronectomy, resulting in pain that persists causing immunosuppression, which may before the application of excessive force, beyond the early post-operative period. This impair healing and those who are being the coronectomy cuts can be improved can usually be attributed to the retention of prepared for treatment with bisphosphonates, and procedure completed with the use mobilized roots or the presence of enamel on radio- or chemotherapy. of only minimal pressure. If this is not the the retained tooth fragment. Root removal In their 2012 paper, Gleeson et al10 case and the roots are mobilized during will usually be necessary in these situations. elegantly described a six stage coronectomy instrumentation, they must be removed The long-term complications technique for use on M3Ms. This approach using a technique least likely to result in associated with M3M coronectomy relate to translates well for use on other unerupted nerve damage, which is often the result of the migration and eruption of the roots left teeth; key features are summarized in Table 1. mechanical compression rather than direct in situ. A degree of movement in an occlusal In the hands of an experienced trauma. direction is commonly seen on radiographs operator, the coronectomy of M3Ms has In the early post-operative taken after coronectomy, although there is been shown to be a safe and effective period, pain, alveolar osteitis and infection no indication to take radiographs specifically procedure,5,10 although evidence for similar may complicate coronectomy, as they can to monitor this. In the majority of cases, success with other teeth is largely anecdotal. the extraction of teeth. The regular use of this migration is self-limiting and the roots As for any surgical intervention, it is essential simple analgesics usually suffices; infection remain entirely within the alveolar bone. to recognize possible post-operative and alveolitis should be managed as if an Rarely, over a number of years, continued Technique Rationale Incision Small, full thickness 3-sided flap Adequate access Preserve papilla mesial to M3M Aids later primary closure Use of Minnesota retractor during procedure Prevents avoidable trauma to mucosa Exposure Use of fissure bur to expose CEJ Exposes site of coronectomy Remove bone to allow sectioning and removal of crown Vital tissue preserved only Refer to available imaging if IAN occupies a superficial Avoidance of inadvertent damage to IAN buccal position Decoronation Partially section the tooth 1−2 mm below CEJ To reduce likelihood of retained enamel Cut across 3/4 of the bucco-lingual width of tooth, To ensure that inadvertent breach of the lingual plate along its full length and soft tissues does not result in lingual nerve injury Remove crown by rotating a narrow Couplands elevator This propagates a fracture through the remaining in deepest point of coronectomy cut lingual enamel wall Use only minimal force, if resistance encountered The application of greater pressure increases the risk of consider adequacy of depth of cut mobilizing root fragments and nerve injury Finishing of the Use round bur to reduce the cut surface of the root face Encourages bony deposition surface of the to 2−3 mm below the alveolar crest root Remove any remaining enamel This inhibits bony healing Remove remnants of coronal pulp This may reduce post-operative discomfort Debridement of Irrigate with saline Allows careful inspection of socket socket Ensure all debris removed Optimizes healing Final check to ensure complete removal of enamel and Optimizes healing depth of retained roots Closure Tension-free, primary closure should be achieved using Promotion of healing and minimization of post- interrupted sutures operative discomfort