Patients are becoming more educated in the available treatments and will ask for services by name. This paper offers a treatment option that preserves tooth structure in cases that are carefully selected. In the right situation a fine restorative result can easily be attained using the hemi-section option.
In every clinical situation there are a wide variety of treatment options that can be undertaken. Patients are enquiring about the latest in treatment options and materials available. Implants and veneers are examples of heavily marketed treatment modalities that patients are coming into dental offices and asking for by name. As practitioners of the art and science of dentistry 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 best available clinical evidence of successful treatment modality.
The loss of posterior molar can result is several undesirable sequelae including shifting of teeth, collapse of the vertical dimension of occlusion, super eruption of opposing teeth, loss of supporting alveolar bone and a decrease in chewing ability. The treatment options to replace severely damaged and possibly unrestorable teeth include removable partial denture, fixed partial denture and dental implants. A guiding principle should be to try and maintain what is present.
This case study presents one treatment option available in cases of extensive decay in molars or molars affected by extensive periodontal lesions that threaten the loss of the tooth. Hemi-section of the effected tooth allows the preservation of tooth structure, alveolar bone and cost savings (time and money) over other treatment options. The term hemi-section refers to the sectioning of a molar tooth with the removal of an unrestorable root which maybe affected by periodontal, endodontic, structural (cracked roots), or caries. Careful case selection determines the long term success of the procedure.1
Indications for hemi-section include:
1. The tooth is affected by caries, vertical root fracture, periodontal disease or iatrogenic root perforation where only one root of a multirooted tooth is affected.
2. The surviving root is accessible and treatable endodontically.
3. The surviving root is structurally capable of supporting a dowel and core restoration.
4. The surviving root is aligned so as to provide proper draw for the resulting fixed prosthetic restoration.
5. The root morphology allows for surgical access and proper periodontal maintenance of the final restoration.2-9,12
Contra indications to using a tooth root as an abutment can include:
1. Poorly shaped roots or fused roots.
2. Poor endodontic candidates or inoperable endodontic roots.
3. Patient unwilling to undergo surgical and endodontic treatments and undertake the care or the resulting restoration.2-9,11,12
Risks of this treatment modality include:
1. Increased risk of caries in the area of the resection due to increased difficulty in hygiene of the area.
2. Increased stress on abutment teeth if the span is too wide because of the loss of 50 percent of root structure resulting in mobility (periodontal) or fracture due to structure loss.1-9,11,12
A 63-year-old male in good health presented at our General Practice Clinic Program for comprehensive treatment. During the examination, a large caries lesion was discovered under a crown in the mesial root of tooth 36 (lower left first molar). The caries extended sub gingivally, impinged upon the furcation and was considered too deep to restore. The distal root was in very good condition with excellent periodontal support. The opposing arch had no opposing molar occlusion. The patient indicated there was no pain but did not wish to have the tooth removed. In this case the mesial root was considered a risk for bicuspidization as crown lengthening would have been required. It was felt that the crown lengthening would have reduced the overall periodontal prognosis in this case because of the loss of bone support for both roots.
The option of root resection and hemi section was discussed with all the risks explained. The patient agreed to this treatment option.
The following appointment included the removal of the existing crown and endodontic access to the distal root. Endodontic treatment was completed and the patient was scheduled for the resection and removal of the mesial root. A surgical approach to gain access for adequate vision of the furcation in order to section the root is the most predictable technique. A direct root resection could be undertaken in this case because the crown had been removed to complete the endodontic therapy. The tooth was carefully sectioned and the damaged mesial root was removed. Any defects on the sound distal root were smoothed. The distal root as temporized with IRM (Dentsply International Inc. Milford De. USA) and the surgical site was then allowed to heal with no occlusal stress placed on the root for four weeks.2-4,7,8
The next phase of the restoration of the hemi-sected tooth was the fabrication of a custom cast gold post and core.10 The lower second pre-molar #35 had an existing porcelain fused to metal restoration that was removed. A plastic burnout post (Directa AB Sweden) and GC pattern material (GC America Inc. Alsip Il. USA ) was shaped to allow for the retained distal root of the # 36 to act as a distal abutment for a fixed partial denture from this retained distal root to tooth #35.3,10 The pattern was cast in Type III gold (Argen Corp. San Diego Ca. USA) and returned for seating and refining. The draw between the two abutment teeth was confirmed after minimal adjustment of the cast post and core and an impression was made for the fabrication of a fixed partial denture.
A hygienic pontic was selected to allow for simplicity of cleaning and take into account the continual change in the contour of the soft tissue as the framework for the fixed partial denture was returned for trial fit prior to the healing continues. Finally the shade of porcelain was selected and the fixed partial denture sent out for final porcelain application.
The completed restoration was evaluated for fit, occlusion, as well as shade was confirmed. Then with the patients consent, the restoration was definitively cemented (Relyx Luting Plus cement 3M (ESPE St. Paul, Mn.). The patient was recalled one week later and again at one month to confirm the continued healing of the site was well as the health of the surrounding tissues.
This case demonstrates an alternative treatment to extraction of a whole tooth and salvation of healthy tooth structure in a case where the patient did not wish to have the tooth removed. The success of the treatment depends on careful case selection based on a firm set of guidelines. In this case the tooth had a very healthy periodontium supporting the distal root. The root also had sound straight root structure that was ideal for endodontic treatment as well being long enough to act as support for the cast post and core. The angulation of the remaining root was ideal for the creation of draw in the fabrication of the resulting final fixed restoration. Finally, the patient was motivated to try and save as much of the tooth as possible. He is fully aware of the risks including the increased risk of caries in resected tooth. The fact that the opposing arch is edentulous at this time reduces the occlusal stresses placed on the restoration.
The use of hemi-section to retain a compromised tooth, in the restoration arsenal of th
e restorative dentist offers a predictable treatment option with a prognosis comparable to any tooth with an endodontic treatment. The key, with any restorative treatment, is to balance the factors that indicate the procedure is a suitable one to be undertaken vs. the contra indications. In other word a solid diagnosis. This article presents a technique for the dentist to offer patients to maintain tooth structure where that structure is compromised. The developments in surgery, periodontal, endodontic, and restorative dentistry provide for predictable restoratives options that can be offered to patients. Success rates in the range of 60% over a ten year period can be expected.1,11 As the population ages and is more determined to keep their teeth for longer periods hemisection provides one more treatment option. OH
Anthony T. Nowakowski, B.Sc. DM General Practice Course Co-ordinator, Alex Serebnitski, Fourth Year dental student, and Igor J. Pesun, MS, Department of Restorative Dentristry, Faculty of Dentistry, University of Manitoba.
Oral Health welcomes this original article.
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