CLINICAL TECHNIQUES IN PERIODONTICS

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The Role of Root Resection in the Age of Dental Implants

by Laura Minsk, DMD; Alan M Polson, DDS, MS

Laura Minsk, DMD Assistant Professor of Periodontics University of Pennsylvania School of Dental Medicine Philadelphia, Pennsylvania Diplomate American Board of Periodontology Private Practice Limited to Periodontics and Implant Dentistry Media, Pennsylvania Alan M Polson, DDS, MS Professor of Periodontics D Walters Cohen Chair Director of Periodontal Clinical Research University of Pennsylvania School of Dental Medicine Philadelphia, Pennsylvania

Traditional Concepts
Periodontal attachment loss associated with marginal periodontitis around multi-rooted teeth can progress to the furcation area. Because of the physical inaccessibility for hygiene procedures, infections in this area present a considerable therapeutic challenge with the potential for continued periodontal breakdown. Consequently, the objective of periodontal furcation treatment is to eliminate the plaque-retentive areas in the exposed furcation and make the area more accessible for maintenance. Success depends on the magnitude to which the periodontal infection has invaded the furcation area. Early furcation involvement (just into the fluting of the furcation—typically, Degree I)¹ may be treated by therapeutically debriding the area, addressing the etiologic factors (eg, overhanging restorations, enamel projections) and improving hygiene access to the furcation entrance through odontoplasty. However, moderate to advanced furcation involvement, which includes destruction of the bone and connective tissue distinctively into or through the furcation (typically, Degrees II or III)¹ may present more of a therapeutic challenge. Studies suggest that because it may be impossible to effectively remove plaque and calculus from some furcations,^2-4 the prognosis for these teeth may deteriorate sharply.^5-7

Moderate to advanced furcation involvement, or through-and-through furcation involvement, often requires surgical intervention. However, surgical debridement of the furcation alone may not be sufficient to improve the long-term prognosis. The long-term success of the treatment depends on the access for plaque removal and the patient's ability to perform daily plaque debridement. To achieve this, clinicians may choose to remove 1 or more of the involved roots in a procedure known as root resection.⁸ The conventional indications and contraindications for a root resection are shown in Table 1. This article describes the technique of a root resection, gives new information about outcomes, and analyzes the role of this treatment modality in the era of dental implants.

Root Resection Technique
The first step in performing a root resection is to determine which root will be removed. Radiographs and clinical examinations (including periodontal probing) are used to assess the extent of the furcation involvement, the amount of attachment loss, the morphology and proximity of the roots, the ability to perform endodontic therapy, the proximity of anatomical structures, and the existence of caries or root resorption. It is typical that the root with the least amount of remaining bony support or the most difficult for the endodontist or restorative dentist to treat should be removed. Because of the high incidence of furcation involvement in maxillary teeth and the anatomy and relation of the first and second molars, the root most commonly resected is the disto-buccal root of the maxillary first molar^9-11(Figures 1 through 7).

It is generally agreed that whenever possible, endodontic treatment should be performed before a root resection. This facilitates the performance of the endodontic obturation and allows the endodontist to determine whether the canals can be adequately instrumented. Knowing in advance that endodontic therapy can be done on the root or roots that remain after a resection ensures clinical feasibility for the procedure.^12,13 In addition, performing endodontic treatment before a root resection may minimize the potential for post­operative pain.¹⁴ When necessary, however, root resections also may be done successfully on vital teeth.^14,15 In these situations, endodontic treatment should be completed soon after the root resection to avoid pulpal complications.^14,15

After reviewing the patient's medical history and treatment plan, the patient is prepared for periodontal surgery and anesthetized. If the resection of the root requires cutting through metal restorations or involves considerable removal of coronal tooth structure as in a trisection procedure,¹² it should be done before the incision and reflection of the flap to prevent metallic fragments and tooth particles from becoming embedded in the soft tissues.

Access to the root surface is gained by elevating buccal and lingual full-thickness muco­periosteal flaps. The extent of the flap must be sufficient to provide access and visibility for instrumentation and to facilitate proper wound closure. All chronic inflammatory tissue is removed with curets, exposing the bone and root surfaces. In the case of a single root resection, a long fissure or diamond bur is used to section the root by positioning it at the most coronal portion of the root (the roof of the furcation) and gently penetrating through the furcation. Complete root separation is verified by inserting a probe through the furcation and removing it through-and-through or by testing the mobility of each root individually.

Once the root is cleanly separated from the remaining roots and the crown of the tooth, it can be elevated carefully from its socket with elevators to avoid luxating or damaging the remaining roots. In cases where root curvature may pose a problem during elevation, it may be necessary to progressively section and remove the coronal portion of the root as it is elevated until the root can be removed from the socket. Once the resected root has been removed, odontoplasty should be performed to ensure that no "lip" of tooth structure, which would act as a plaque-retentive ledge, is left in the dome of the furcation (Figure 8).

After the removal of the root, the remaining root surfaces are planed to remove deposits, all soft tissue in the furcation area is curetted, and an ostectomy or an osteoplasty is performed to eliminate the remaining bony deformities and provide a biologic width for the dentogingival complex after healing.¹² If a vital root resection is performed, a small round bur is used to remove part of the pulp tissue from the exposed canal, and a dressing of zinc oxide and eugenol is placed over the amputated pulp.¹⁶The flaps are then re-approximated and sutured. Postoperative instructions are similar to other periodontal surgical procedures, and the patient should be reinstructed on oral hygiene procedures, which are specific for the new dento-radicular morphology.

The restoration should be made to allow oral hygiene access for the patient and the clinician.¹⁰ Teeth that have had a root resected are in the clinical category of a reduced but healthy periodontium and may benefit from splinting to the adjacent teeth, especially if the mobility is increasing.¹⁷The amount of alveolar bone support, the mobility of the tooth, and its ability to withstand occlusal forces will dictate the need and extent of the occlusal adjustment or a splinted, fixed restoration (Figure 9).

Clinical Significance of Root Resection in the Age of Dental Implants
Root resections have been performed in dentistry since the late 1800s.¹⁸ With proper long-term monitoring and maintenance, a root resection is accepted as a valid treatment with reasonable long-term effectiveness.^1,9,19-21 In a recent report on periodontal outcomes in a private practice setting in teeth followed a minimum of 10 years after active treatment, Polson and Blieden found that 90% of root-resected teeth were maintained in a stable state long term²¹ (Table 2). Complications and failures were mainly of an endodontic nature^21,22 and tended to occur 10 years or more after the resection procedure.²²

However, therapeutic measures performed to ensure the retention of a tooth can be complex, time consuming, and costly. Root resection commits the patient, not only to periodontal and endodontic treatment, but may also involve a major restorative procedure. With the increased use of endosseous dental implants to replace failed or failing teeth, the role of a root resection as part of the periodontal treatment armamentarium has come into question.

Root resection can be a valuable procedure when the tooth in question has a very high strategic value or when specific problems exist that cannot be solved by any other therapeutic approach. Root resections may be the treatment of choice when the proximity to anatomical landmarks (eg, maxillary sinus, mandibular canal) limits the amount of bone available for dental implants. In addition, the presence of the remaining root complexes will maintain the alveolar bone associated with them, which prevents the resorptive process. In the 30 cases shown in Table 2,²²the retained roots were distributed in mandibular first (n=2) and second (n=3) molar locations, and maxillary first (n=18) and second (n=7) molar locations.

As a future biologic therapeutic potential, some recent studies have shown that the periodontium of similar types of roots retain their biologic potential, and orthodontic tooth movement vertically and horizontally, into and through atrophic alveolar ridges, is accompanied by adjacent alveolar bone formation, and these new alveolar bone augmentation sites may be appropriate for implants.^23-27A further consideration for root resection is that if the involved tooth is already part of an existing splinted restoration, the resection of a root may help preserve the prosthesis and minimize treatment time and cost. Finally, medically compromised patients may benefit from the maintenance of existing roots, avoiding multiple reconstructive surgical procedures.

References
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2. Matia JI, Bissada NF, Maybury JE, et al. Efficiency of scaling of the molar furcation area with and without surgical access. Int J Periodontics Restorative Dent. 1986;6:25.

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4. Wylam JM, Mealey BL, Mills MP, et al. The clinical effectiveness of open versus closed scaling and root planing on multi-rooted teeth. J Periodontol. 1993;64:1023-1028.

5. Hirschfeld L, Wasserman B. A long-term survey of tooth loss in 600 treated periodontal patients. J Periodontol. 1978;49:225-237.

6. McFall WT Jr. Tooth loss in 100 treated patients with periodontal disease. A long-term study. J Periodontol. 1982;53:539-549.

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8. Glossary of Periodontic Terms. J Periodontol. 1986;57(suppl):23.

9. Klavan B. Clinical observations following root amputation in maxillary molar teeth. J Periodontol. 1975;46:1-5.

10. Eastman JR, Backmeyer J. A review of the periodontal, endodontic, and prosthetic considerations in odontogenous resection procedures. Int J Periodontics Restorative Dent. 1986;6:34-51.

11. Majzoub Z, Kon S. Tooth morphology following root resection procedures in maxillary first molars. J Periodontol. 1992;63:290-296.

12. Greenstein G, Caton J, Polson A. Trisection of maxillary molars: a clinical technique. Compend Contin Educ Dent. 1984;5:631-632.

13. Lindhe J, Karring T, Lang N. Clinical Periodontology and Implant Dentistry. 3 ed. Malden, MA: Munksgaard; 1997.

14. Smukler H, Tagger M. Vital root amputation. A clinical and histological study. J Periodontol. 1976;47:324-330.

15. Haskell EW, Stanley HR. A review of vital root resection. Int J Periodontics Restorative Dent. 1982;2:28-49.

16. Basaraba N. Root amputation and tooth hemisection. Dent Clin North Am. 1969;13: 121-132.

17. Polson AM. Periodontal considerations for functional utilization of a retained root after furcation management. J Clin Periodontol. 1977;4: 223-230.

18. Amen C. Hemisection and root amputation. Periodontics. 1966;4:197.

19. Bergenholtz A. Radectomy of multirooted teeth. J Am Dent Assoc. 1972;85: 870-875.

20. Erpenstein H. A 3-year study of hemisectioned molars. J Clin Periodontol. 1983;10:1-10.

21. Buhler H. Evaluation of root-resected teeth. Results after 10 years. J Periodontol. 1988;59:805-810.

22. Polson AM, Blieden T. Long-term outcomes after periodontal therapy: III. Fate of resected teeth [abstract]. J Periodontol. 2002;73:1092.

23. Salama H, Salama M. The role of orthodontic extrusive remodeling in the enhancement of soft and hard tissue profiles prior to implant placement: a systematic approach to the management of extraction site defects. Int J Periodontics Restorative Dent. 1993;13:312-333.

24. Mantzikos T, Shamus I. Forced eruption and implant site development: an osteophysiologic response. Am J Orthod Dentofac Orthop. 1999;115: 583-591.

25. Zachrisson BB, Bjorn U Zachrisson, DDS, MSD, PhD, on current trends in adult treatment, Part 2. Interview by Robert G Keim. J Clin Ortho. 2005;39: 285-296.

26. Roberts WE, Engen DW, Schneider PH, et al. Implant-anchored orthodontics for partially edentulous malocclusions in children and adults. Am J Orthod Dentofacial Orthop. 2004;126:302-304.

27. Nozawa T, Sugiyama T, Yamaguchi S, et al. Buccal and coronal bone augmentation using forced eruption and buccal root torque: a case report. Int J Periodontics Restorative Dent. 2003;23:585-591.

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