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Hemisection as an AlternativeTreatment for VerticallyFractured Mandibular Molars

Gregori M Kurtzman,DDS, MAGD, FACDAssistant Clinical ProfessorDepartment of Endodontics,Prosthetics, and OperativeDerrtistryUniversity of MarylandBaltimore College of DentalSurgeryBaltimore, MD

Lee H Silverstein, DDS,MS, FACDAssociate Clinical Professor

Peter C Shatz, DDSAssistant Clinical Professor

Department of PeriodontologyMedical College of Georgia,School of DentistryAugusta, Ceorgia

he treatment of severe furcalbone loss may require theremoval of a portion of the

anatomic crown and its associated rootor resection of only 1 root from a mul-tirooted tooth.r This type of surgicaltherapy enables clinicians to betteraccess the remaining tooth structure forperiodontal and subsequent prosthetictherapy. The morphology of the neces-sary tooth preparation for root resec-tion, in this case hemisection, requiresthat the final anatomic form must nothamper the patient's ability to accom-plish optimal long-term maintenanceof the affected area.'

Prosthetic therapy and restorativesequencing is often complicated whenperiodontal attachment loss, caries, ortooth fracture involves the furcation areaof the multirooted molar. Although suchinvolvement invariably diminishes thelong-term prognosis of the affected teeth,extraction is not necesarily an option.Hemisection periodontal therapy, whichinvolves removal of the involved rootand its asociated crown portion, is oneof several treatment modalities that canbe used in such cases.

It is important for dentists to knowthe necessary indications/contraindica-tions, surgical techniques, and prostheticmanagement for successful hemisectionperiodontal therapy. Hemisection thera-py is a predictable treatment modalitywith a high degree of success if some

basic considerations are followed.la Forexample, in the case presented, fractureof the mandibular molar root may notdoom the remaining unaffected portionof the tooth to extraction. When thehealth of the other root is sound, hemi-section may be used to provide a premo-lar-shaped restoration.

Case PresentationA 40-year-old man presented with

the complaint of a rough area on hislower right first molar. Examinationrevealed a vertical fracture of the distalroot. The cause of the fracture wasunknown. The tooth had undergoneprior endodontic therapy and wasasymptomatic. There was no evidence ofa crown or a post and core. Radio-graphically, it was evident that the distalroot had a fracture separating the rootinto 2 parts (Figure l). A radiolucentlesion was noted extending coronallyfrom the apical tip to the furcation. Sur-prisingly, neither tooth portion demon-strated any mobility (Figure 2). Themesial root lacked pathology and testednegative for percussion. The only othermandibular teeth missing were the rightsecond molar and third molars bilateral-ly. Periodontal health was normal andno other restorations or decay were pre-sent on the remaining teeth.

Tieatment options were discussedand it was decided to save and restorethe mesial root of tooth No. 30 because

Abstract: Hemisection of mandibular molars may be a viable treatment optionwhen vertical root fracture has occurred and the other root is healthy. This arti-cle discusses a case that presents the techniques involved in hemisection andrestoration of the remaining tooth.

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Figure 1-lnitial presentation of tooth No, 30 demonstrating ver-tical root fracture and pathology ass0ciated with the distal root.

of financial considerations. When financesallow, future treatment will include placementof an implant distal to the restored mesial rootand restoration with a fixed single crown.

The patient returned 8 months after theinitial consultation to initiate treatment;finances had improved and he now had insur-ance benefits. Clinically and radiographically,no changes had occurred and the patient indi-cated that the area remained symptom-free.

Local anesthetic was applied via a mentalblock and periodontal ligament injection with4% septocaine with 1:100,000 epinephrine. Acoarse tapered diamond was used in a highspeed handpiece with water to place a cut fromthe buccal to the lingual through the furcation(Figure 3). Periotomes were used to luxate themost distal root fragment by gentle apicallydirected force into the periodontal ligamentspace. The segment was then removed with arongeur. The periotomes were then introducedinto the cut placed at the furcation, and theremaining root was moved distally andremoved with the rongeur (Figures 4 and 5).The diamond was used to remove the lip at thefurcation on the mesial root and elirninate anyundercut that might trap plaque. The old com-posite core was removed, and the orifices forthe mesial-buccal and mesial-lingual canalswere identified. A bipolar unit was used totrough the sulcus around the remaining root toexpose more root structure and improve the fer-rule affect for the future crown. Bleeding on themesial papilla was additionally controlled withthe bipolar unit (Figure 6).

Peeso burs were used to prepare a postspace in both canals to a diameter of 1.25 mmand a depth of 10 mm. An adhesive was applied

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Figure 2*Clinical presentation demonstrating the vertical rootfracture of the distal root.

Figure 3-Hemisection cut made with a diamond through thefurcation.

Figure 4-Distal root fragments and old composite on mesialroot removed. Canal orifaces were identified on the mesial-buc-cal and mesial-lingual canals. Note the osseous exostosis on thebuccal olate,

Compendium i February 2006 863

Figure S-Distal root fragments after extraction.

Figure 7-Posts were luted into the 2 mesial canals with a dual-cure resin cement. Blue dual-cure resin core material was inject-ed in and around the posts to create a core.

into each post preparation and all exposeddentin. Excess adhesive was removed withpaper points. A dual-cure resin cement wasinjected into the post spaces and a post wasinserted to length. Excess luting agent wasremoved from around the posts by applicationof air with the air/water syringe. A contrastingcolor dual-cure resin core material was injectedaround the posts and built up coronally (Figure7). After setting of the materials, the excesslength of fiber post was reduced and the corewas shaped, keeping the restoration out ofocclusion (Figures 8 and 9).

The patient returned after 4 weeks of post-surgical healing. The soft tissue had healed atthe distal root, and the mesial root remainedasymptomatic. Preparation of the mesial rootwas made to accept a porcelain-fused-to-metal(PFM) crown. The contrasting color of thecore material assisted in ensuring adequate fer-

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Compendium / February 2006

Figure 6-Clinical site demonstrating the soft tissue at the distalroot, A bipolar unit was used t0 expose more of the mesial rootand control a spot of hemorrhagic tissue on the mesial papilla.Canals prepared for 1.25 mm fiber posts.

Figure 8-The core was shaped and excess post length wasadjusted.

rule in the preparation. A nontraumatic retrac-tion materialu was injected into the sulcus, anda Comprecapb was placed over the preparation.The patient was instructed to bite into theComprecap, and occlusion was maintained for5 minutes to provide better capture of the mar-gins. Correct-Plus, a light-body po$vinyl silox-anec was subsequently injected around thepreparation, and a full-arch impression trayfilled with medium-body polyvinyl siloxanecwas inserted. An opposing full-arch impressionand bite were taken. A temporary crown wasfabricated and luted with temporary cement.

The patient returned several weeks later forcompletion of treatment on tooth No. 30. Thetemporary crown was removed and the finalrestoration tried in. Occlusion was checked andthe PFM crown was luted with a dual-cure resincement (Figures 10 and 11).

The full-coverage crown should preventany further fracture of the tooth that remains.Had the tooth originally been crowned, it maynot have fractured.

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Figure 9-Radiograph taken after hemisection and posUcorefabrication in the mesial root.

Figure 10-Radiograph taken 1 month after surgery. Bone fill isdemonstrated in the distal root space and lack of apical patholo-gy on the mesial root.

Figure 11-Completed porcelain-fused-to-metal crown restoringthe tooth to function,

DiscussionIn situations when resection periodontal

therapy can be predicted, initiation of conven-tional endodontic treatment before therapy sim-plifies the surgical procedure. This is often thecase because tooth preparation can invade thepulp chamber andjeopardize control ofthe coro-nal seal ofthe endodontic acces opening, com-plicating the completion of endodontic therapy.

When choosing to perform a hemisectionprocedure, consideration should be given to themorpholory, clinical length, and shape of theroots of a multirooted tooth. The divergence of

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the roots is an important indication. Affectedteeth with roots spread apart facilitate the clin-ician's ability to perform a root resection; teethwith closely approximated or fused roots shouldnot receive hemisection therapy.

Conversely, the contraindications to per-forming hemisection periodontal therapyinclude a nonphysiologic postsurgical architec-ture that would preclude good home care, or aninadequate amount of alveolar bone remainingto support the existing root structure. Also, ifpulp cannot be treated adequately in the canalsystem of the roots to be retained or this seg-ment of the tooth is nonrestorable, hemisec-tion therapy should not be undertaken.s

After resection therapy, the restorativerehabilitation begins. The current prostheticguidelines for rehabilitation include a conflu-ence of the root and the prosthetic crown con-tours. In addition. the axial tooth contours ofthe restored resected teeth should have a phys-iologic contour, which implies that the restora-tion emerges from the root with a zero degreeemergence profile. These transgingival areasshould therefore exhibit a flat prosthetic con-tour at the gingival margin, producing a morehygienic, less plaque retentive region whencompared with a tooth restored with a cervicalbulge at the gingival portion of the prosthesis.G

ConclusionThe removal of a root and the overlaying

anatomic crown is refered to as a hemisection.Hemisection of either a maxillarv or mandibularmolar is often a means of retaining teeth neededfor restorative abutments or occlusal support.This treatment can produce predictable resultsas long as proper diagnostic, endodontic, surgi-cal, and prosthetic procedures are performed.

Referencesl. Glickman T. Clinical Periodontologlr. lst ed. Philadelphia,

PA: WB Saunders; 1953.Silventein LH, Moskowitz ME, Kurtzman D, Shatz PC.Prosthetic considerations with periodontal root resectivetherapy, Part 2. Hemisections . Dent Today, I 999; I 8:86-89.Hernpton T Leone C. A review of root reseotive therapyas a treatment option for maxillary molars, J Am DentAssoc. 1997; I 28:449-455.Cohen E. Atlas of Cosmetic and Reconstructive PeriodontalSurgery. 2nd ed. Philadelphia, PA: Lea & Febiger; 1994.Appleton IE. Restoration of resected teeth. J Prostfi Dent.1980;44:1 50- I 53.Rosenberg M, Keough B, Kay H, et al. Periodontal andProsthetic Management for Advanced Cases. Chicago, IL:Quintesence Publishing Co; 1988.

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