Hemisection refers to the removal or separation of root with its accompanying crown portion. This procedure represents a form of conservative dentistry, aiming to retain as much of the original tooth structure as possible in selected compromised cases where tooth replacement alternatives may be preferred to be deferred for as long as possible, or may be complicated due to biologic or financial reasons. The case below describes the successful management of a compromised endo:perio – involved tooth with endodontic treatment and a hemisection procedure.
A 67 year-old patient was referred for endodontic assessment of his non-vital and infected tooth 36. Clinical examination revealed that tooth 36 was non-vital and infected with extensive peri-radicular bone loss noted particularly around the distal root. Recession was noted extending to the apex of the distal root. Upon further questioning, the patient informed me that adjacent tooth 37 had previously been diagnosed with advanced periodontal disease and had been extracted in the preceding months and the periodontal bone loss associated with 37 had also involved the distal aspect of adjacent tooth 36. I took a cone beam CT to further assess the tooth and noted the extensive nature of the bone loss around the distal root of 36, but the mesial root appeared to still have a reasonable amount of crestal bone cervically with no overt probing defects. Periapical bone loss was noted around the mesial root as a result of the endodontic infection.
- Pre-operative PA of tooth 36
- Selected CBCT slices taken pre-operatively showing extensive bone loss around entire distal root of tooth 36; apical lesion noted associated with mesial root due to endodontic infection but intact furcal bone noted cervically
After discussing these findings with the patient, I informed him of the very uncertain long-term prognosis of tooth 36. If an attempt to retain tooth 36 was to be considered, I advised him that the only viable option in this case may be to consider endodontic treatment of the mesial root and to plan for hemisection and removal of the distal root and distal part of the crown, reshaping the molar into a bicuspid form. This would facilitate a more stable periodontal situation and some hope of trying to retain the tooth for as long as possible. The patient was informed that the tooth is still at risk of root fracture in the long-term. I also advised the patient to seek a periodontal opinion regarding possible implant replacement. Considering the extensive alveolar bone loss in the area and the position of the mandibular canal, the Periodontist was also of the opinion to try to retain 36 for as long as possible as implant replacement in this site was complicated by the bone loss in the area.
Following finalization of his treatment plan, the patient was seen again for management at which time endodontic treatment was performed on the mesial root of tooth 36 with the canals conservatively shaped, disinfected and obturated with GP/AHPlus and the distal aspect of the crown and root resected. The tooth was restored with a polycarboxylate/GIC base and an amalgam overlay restoration with flat cusps kept out of lateral guidance.
(a) Pre-operative image of tooth 36; (b) Following endodontic treatment and distal crown/root hemisection and removal; (c) Post-restoration following placement of amalgam overlay.
The patient was seen recently for a review 15 months following his endodontic care with the tooth found to be asymptomatic and functional. Excellent healing of the large pre-operative peri-radicular bone loss was noted with normal periapical tissues.
- Pre-operative, immediate post-treatment and 15-month review PAs of tooth 36
For a given clinical situation there are a variety of treatment options that can be undertaken. As clinicians, we owe our patients to be able to provide a wide range of treatment options based on the clinical situation, age, economical considerations of the patient, and the available clinical evidence. At a time where the use of prosthetic replacements with implants have become more popular in the replacement of compromised teeth, alternatives such as hemisection and root amputations may still warrant consideration as a conservative option in selected cases where implant replacement may be reconsidered at a given time due to complexity or costs. These procedures may allow the patient to try to retain his/her natural teeth for as long as possible, preserving all available replacement options if needed in the future.
The success of these procedures for compromised teeth require proper restorative and endodontic treatment planning and long-term periodontal maintenance. As with any procedure, the patient should also have a clear understanding of the relevant risks:benefits of the procedure. The most common issues leading to failure of teeth following hemisection procedures are root fractures and issues with recurrent caries and leakage. The occlusion was reviewed in this case with the tooth built up with a direct overlay with a narrow occlusal table and flat cusps kept out of any lateral guidance. The hemisection procedure was also performed keeping in mind the need to preserve as much cervical tooth structure as possible to reduce the risk of fracture. The endodontic instrumentation was carried out conservatively to minimise any excessive root dentine from over-flaring the curved canals. Amalgam was used in this case as the restorative margins involved the root dentine and was a preferred direct overlay material over composite resin from a microleakage perspective. The patient was also more concerned with function over aesthetics in this region. A direct overlay was preferred to a crown in this case considering costs:benefits and prognosis.