EFFICACY OF AN ORAL RINSE 9. Lamb DJ, Martin MV. An in vitro and in viva study of the effect of incorporation of chlorhexidine into autopolymerizing acrylic resin plates upon growth of Candida c&cans. Biomaterials 1983;4:205-9. 10. Speichowicz E, Santarpia III RP, Pollock JJ, Renner RP. In vitro study on the inhibiting effect of different agents on the growth of Candida albicans on acrylic resin surfaces. Quintessence Int 1990;21:35-40. 11. Bantarpia III RP, Renner RP, Pollock JJ, Gwinnett AJ, Brant EC. Model system for the in vitro testing of a synthetic histidine peptide against Candida species grown directly on the denture surface of patients with denture stomatitis. J PROSTHET DENT 19&38;60:62-70. R -retained overdentures: edentulous ridges 12. Newton AV. Denture sore mouth. Br Dent J 1962;112:357-60. 13. Budtz-Jorgensen E. Hibitane in the treatment of oral candidiasis. J Clin Periodontol 1977;4:117-28. 14. Ray TL. Oral candidiasis. Dermatol Clin 1987;5:660-2. Reprintrequeststo: DR. ROBERT P. RENNER SCHOOL OF DENTAL MEDICINE STATE UNIVERSITY OF NEW YORK AT STONY BROOK STONY BROOK, NY 11794 Part II-Managing trau and opposing dentitio Yair Langer, DMD,a and Anselm Langer, DMDb The Maurice and Gabriela GoldschlegerSchool of Dental Medicine, Tel Aviv, and Hebrew University-Hadassah School of Dental Medicine, Jerusalem,Israel Tel Aviv University, Overdentures designed to prevent direct oeclusal either forestall or reduce residual ridge resorption. to improve abnormal maxillomandibular relations, and estlneties. (J PROSTHET DENT 1992;61:77-81.) trauma to the residual ridge may Overdentures may also be used thereby enhancing both function etaining and reducing terminal teeth to roots to use as overdenture abutments is the last line of defense before rendering the jaw completely edentulous.1-3 However, overdentures may have broader applications for treatment planning. As well as improving denture function, they may be used as effective prosthodontic means for correcting disparities in dentition between the two dental arches and for treating occlusal disharmony. An example is an edentulous jaw opposed by a complete natural dentition. Their combined performance is determined by the conditions governing the proficiency of the complete denture rather than by those of the opposing natural teeth.* ~O~RI~ATION SYNDROME The periodontal apparatus is capable of withstanding great functional and parafunctional forces. Tooth- and root-borne restorations totally or partially inherit this ability, depending on the amount and quality of the periodontal support. However, in an edentulous jaw, the bony and mucoperiosteal foundation supporting a complete denture is not capable of comparable function. aInstructor, Section of Oral Rehabilitation, Tel Aviv University, The Maurice and Gabriela Goldschleger School of Dental Medicine. bProfessor Emeritus, Department of Prosthodontics, Hebrew University-Hadassah School of Dental Medicine. 10/1/25938 THE JOURNAL OF PROSTHETIC DENTISTRY Fig. 1. Extrusion of anterior teeth and bone resorption under distal-extension removable partial denture bases in combination syndrome. Despite the many patterns of tooth loss, the mandibular anterior teeth often survive the longest. Langer and Michman5 found that the survival rate was four times that of other teeth for mandibular canines, followed by the mandibular incisors, premolars, and molars, The distribution pattern of remaining teeth was approximately the same on both sides of the arch. It was similar in the maxillae, but with about 50 % fewer teeth than in the mandible. Clinical experience with complete and partial dentures corroborates these patterns of tooth survival. In a study at the University of California, School of Dentistry, Kelly” 77 LANGERANDLANGER Fig. 2. Extrusion of tuberosities, palatal papillary hyperplasia, and alveolar bone loss are characteristic symptoms of combination syndrome in maxillae. Fig. 4. Preserving roots for overdenture abutments. Fig. 5. Submerging abutments under overdenture base may prevent development of combination syndrome. 3, Alveolar maxillary ridge is well maintained because of retained roots. Fig. reported that in over 25 % of prosthodontically treated patients, complete maxillary dentures occluded with mandibular partial dentures. If the traumatic effect of the anterior mandibular teeth on the opposing maxillary ridge is not prevented in the early stages, the specific clinical condition known as the “combination syndrome” may develop.6 In the advanced stages, the sequelae of this condition include pathologic changes in both jaws: extrusion of the maxillary anterior teeth and bone resorption under the mandibular distal-extension base partial denture (Fig. 1). Qvergrowth of tuberosities, palatal papillary hyperplasia, and bone loss in the anterior ridge in the maxillae can occur (Fig. 2). N OF COMBINATION Early recognition of the risk involving maxillary ridge overloading by anterior mandibular teeth is essential, although the characteristic clinical situation does not 78 inevitably develop. Early prevention is preferable to subsequent cure, and therefore periodic checkups for signs of possible deterioration are important. It is advisable to preserve anterior maxillary teeth whenever possible, thereby protecting the ridge from direct traumatization. If their periodontal apparatus is no longer able to absorb and resist the occlusal load, or the clinical crowns have suffered extensive structural loss, retaining all the available roots is an alternate treatment for helping to preserve the anterior maxillary ridge (Fig. 3). The maxillary canines are the most resistant human teeth strategically positioned at the vulnerable fulcrum points of the dental arch. Some authors have raised objections against retaining them as overdenture abutments. Bone and Click7 concluded that inadaquate denture material thickness over the canine root eminences is conducive to denture fracture, especially when gold copings are applied. They also questioned the suitability of the maxillary canines, owing to the minimal amount of thin labial mucosa and the thick, rolled bulbous tissue near the crowns. Freidline and Wica18strongly advised eliminating the labial undercuts over the root abutments by means of free soft tissue grafts taken from the palate. Kotwalg stated JANUARY 1992 VOLUME 67 NIJMBER I ROT-RETAINED OVEBDENTURES: PART II that leaving the maxillary canines is contraindicated if excessive undercuts are not surgically corrected, since relieving them would compromise the denture borders. These reservations may be satisfactorily resolved by prosthodontic means if clinical and economic considerations permit a more complex approach. Provided that the maxillary base was properly formed and extended, the vulnerable gingival margins may be relieved by removing the interfering labial flange sections. Precision attachments incorporated into the anterior abutments can increase denture retention and stability, compensating for the compromised border seal (Figs. 3 through 5).l” Also, reinforcing the base with a cast metal framework vent base fractures. ANAG~NG COMBINATION should pre- JOURNAL OF PROSTHETIC DENTISTRY resulting from trauma by SYNDROME Various solutions for preventing trauma to the residual anterior maxillary ridge by opposing teeth have been proposed. Saunders et al.ll recommended splinting the remaining mandibular teeth opposing an edentulous maxillae, either by fixed or removable restoration, to serve as a positive support for the partial prosthesis and to maximally cover the basal seat under the distal extension bases. These measures support the reestablished occlusal table on posterior denture teeth, while minimizing contact of the anterior teeth in centric and eccentric positions. Koper12 stressed the importance of recording occlusal relations by pantographic tracings and using fully adjustable articulators for managing such situations. He proposed replacing the missing posterior mandibular teeth with fixed or removable restorations and reinforcing the reconstructed distal occlusion with either metal chewing platforms or bard resin posteriors. The same approach was recommended by Schmitt,13 who likewise presumed that the damage to the maxillary ridge can be prevented or minimized by stabilizing the occlusal table with cast gold occlusal surfaces on posterior denture teeth. However, clinical experience demonstrates that, in the absence of natural posterior tooth support, these are only palliative remedies. In such instances the occlusal table cannot be effectively stabilized on distal extension bases. Their mucoperiosteal foundation yields under the pressure of occlusal loads and the treatment usually fails. Extracting the mandibular anterior teeth is certainly the most effective way of radically solving the problem. However, the decision to render patients completely edentulous has to be carefully considered. Unfavorable anatomic and systemic conditions, a history of poor adaptability, and possible rejection of two complete dentures owing to preconceived ideas and apprehension, may prevent successful adaptation. As a compromise solution, terminal teeth may be prevented from acting as a source of damage by turning them into overdenture abutments. Modified occlusion may prevent a traumatic tooth-to-ridge relation by judiciously adjusting vertical and horizontal overlap. THE Fig. 6. Extensive resorption anterior mandibular teeth. Fig. 7. Augmentation hydroxyapatite. of damaged maxillary ridge with If this condition is halted before severe symptoms develop, the prognosis of such treatment is favorable. Also in patients with severe clinical symptoms, the process may be brought under control. For a patient who suffered from serious discomfort resulting from persistent trauma to the maxillary ridge (Fig. 6), the ridge was surgically augmented with hydroxyapatite (Fig. 7) and the offending teeth were reduced to four overdenture abutments (Fig. S), removing them from direct occlusion (Fig. 9). The palliative effect was immediate. Follow-up examinations revealed,that the situation was stable and further deterioration was prevented. RESTORING OCCLUSAL WITH OVERDENTURES ~A~M~N~ Complete dentures require a balanced occlusal load distribution. They may be unseated by leverage exceeding their ability to withstand the dislodging occlusal forces, particularly in regions directly opposing the antagonists (Fig. 10). Overdenture modality provides an acceptable compromise solution. It uses the roots of residual teeth as 79 EAWGER Pig. 8. Traumatizing ments. teeth become overdenture abut- AND LANGER 10. Maxillary complete denture is dislodged by adverse occlusal leverage. Fig. Fig. 9. New dentures balanced in centric and eccentric positions. Fig. 11. Converting dislodging teeth into overdenture abutments. abutments, while eliminating their dislodging effect (Figs. 11 and 12). In the next example, a woman in her fifties sought treatment because she could not use her complete maxillary denture adequately and was dissatisfied with her facial appearance. Periodontally involved mandibular teeth were pushed labially by tongue thrust and the opposing denture teeth were positioned outside the crest of the ridge to accommodate the occlusion (Fig. 13). Leverage created by the unfavorable oeclusal relations would unseat the complete denture. Her facial profile, disfigured by the prognathic appearance, was not esthetically pleasing. The treatment plan consisted of removal of mandibular posterior teeth because of periodontal breakdown. In addition to the six anterior teeth, two premolar roots were preserved bilaterally, and periodontal surgery was accomplished. All teeth were endodontically treated and reduced to root level. Four abutments suitable for retainers were provided with dowel-coping stud attachments and the rest were left bare and obturated with silver amalgam (Fig. 14). Submerging the abutments under the denture base relieved them from the direct tongue thrust, allowing the development of normal occlusal relations. The mandibular overdenture and the opposing complete denture were arranged in an orthognathic relation and the occlusion was balanced (Fig. 15). Following rearrangement of anterior teeth, the protruding lip contour was corrected, significantly improving the patient’s appearance. 80 SUMMARY Terminal teeth may have traumatic effects on opposing edentulous jaws bearing complete dentures. Usually, the mandibular anterior teeth are the last to survive, and they may cause pathologic changes in both jaws, known as the combination syndrome. Development of the combination syndrome should be anticipated as early as possible. The most rational approach is to forestall it by preserving the maxillary teeth or retaining their roots under the denture base to intercept occlusal loads and preserve the ridge. With edentulous maxillae, the development of the combination syndrome may be prevented or checked by turning the offending mandibular teeth into overdenture abutJANUARY 1992 VOLUME 67 NUMBER 1 ROOT-RETAINED OVERDENTURES: PART II Fig. 12. Restoring balanced occlusal relations. Fig. P3. Periodontally involved mandibular teeth pushed outward by tongue thrust. Opposing complete denture teeth are positioned outside crest of ridge to accommodate occlusion. ments, thereby removing them from direct occlusion with the opposing complete denture. The overdenture modality may also be used to orient abnormal interarch relations into an orthognathic occlusion, thereby enhancing both function and esthetics. Selecting the most suitable roots and deciding whether to cover them with protective copings or to eventually use stud attachments, is based on assessment of the specific clinical requirements, existing alternatives, and economic considerations. REFERENCES 1. Lord JL, Tee1 S. The overdenture: patient selection, use of copings and follow up evaluation. J PROSTHETDENT 1974;32:41-51. 2. Brewer AA, Morrow RM. Overdentures. 2nd ed. St Louis: CV Mosby Co, 1980: chapter 4, 24-36. 3. Prieskel HW. Precision attachments in prosthodontics; overdentures and telescopic prostheses. ~012. Chicago: Quintessence Publishing Co, Inc, 1985. 4. Langer A. Long term preventive aspects in oral rehabilitation of adults and elderly. I. Maintenance of balanced functional jaw interaction. J Oral Rehabil X97&5:129-38. THE JOURNAL OF PROSTHETIC DENTISTRY Fig. 14. Mandibular overdenture based on eight retained abutments, four of which were fitted with stud attachments. Fig. 15. Orientation of dental arches into orthognathic occlusion. 5. Langer A, Michman J. Tooth survival in a multicultural group of aged in Israel. Commun Dent Oral Epidemiol 1975;3:93-9. 6. Kelly E. Changes caused by a mandibular removable partial denture opposing a maxillary complete denture. J PROS~HETDENT 1972;27: 140-50. 7. Boone ME, Click JP. The use of maxillary centrals and laterals in the overdenture patient. Compend Contin Educ Dent 1987;8:748-54. 8. Freidline CW, Wical KE. A method for reducing undesirable labial undercuts for overdenture treatment. J PROSTHETDENT 1981;45:4’72-3. 9. Kotwal KR. Outline of standards for evaluating patients for overdentures. J PROSTHET DENT 1977;37:141-6. 10. Langer A, Langer Y. Root-retained overdentures. Part I. Biomechanical and clinical aspects. J PROSTHET DENT 1991;66:784-9. 11. Saunders TR, Gillis RE, Desjardins RP. The maxillary complete denture opposing the mandibular bilateral distal-extension partial denture: treatment considerations. J PROSTHET DENT 1979;41:124-8. 12. Koper A. The maxillary complete dentures opposing natural teeth: problems and some solutions. J PROSTHET DENT 1987;57:704-7. 13. Schmitt SM. Combination syndrome: a treatment approach. J PROSTHET DENT 1985;54:664-71. Reprintrequeststo: DR. YAIR LANCER 10 RAV ASHI ST. TEL AVIV 69 395 ISRAEL 81
