and Mark H. Johnson,
U.S. Army Dental Activity, Fort Knox, Ky.
1 rosthetic dentistry involves the restoration and maintenance of oral functions, comfort, appearance, and health of the patient by the replacement of missing teeth and contiguous tissues with artificial substitutes.’ Each restoration should be designed for the specific patient being treated. In some cases, a fixed-removable partial denture known as the Andrews bridge (Dr. James A. Andrews, Covington, La.) is superior to the conventional fixed or removable partial denture.
INDICATIONS The fixed-removable partial denture has a pontic assembly that is removed by the patient for preventive maintenance.2 Primary indications for this restoration are cases where the abutments are capable of supporting a fixed partial denture but the residual ridge has been partially lost due to trauma, congenital defects, or other pathologic process so that a conventional fixed partial denture would not adequately restore the patient’s missing teeth and supporting structures (Figs. 1 and 2).
The views presented in this article are the private ones of the authors and are not to be construed as official or reflecting the official viws of the Department of the Army.
A male patient will be used to describe the evaluation and treatment procedure. The patient had a recurring abcess in the interproximal area of the maxillary left central and lateral incisors which was not treatable due to the size of the defect and the proximity of the roots (Fig. 3). The maxillary right central incisor and left canine were adequate abutments for a fixed partial denture. However, the bone loss about the affected teeth was so extensive that when the teeth were extracted the resulting large defect required the prosthesis to restore not only the missing teeth but a large area of supporting structures as well.
Fig. 1. Trauma to anterior restorative problem.
Fixed Prosthodontic Resident, General
Fig. 2. Fixed-removable treatment of choice.
Fig. left both ridge
3. Size of periodontal defect between maxillary central and lateral incisors makes extraction of teeth necessary, resulting in a large residual defect.
Fig. 4. Retainers of restoration are waxed and connected by metal bar. In this case, correct treatment involves the construction of a fixed-removable partial denture. Once the decision is made to construct a fixedremovable partial denture, preliminary phases of treatment involving surgical, operative, endodontic, or periodontic procedures should be completed. If the treatment plan requires the extraction of teeth in the pontic region (Fig. 3), the extractions should be accomplished and a temporary appliance fabricated until the tissue heals. After the preliminary treatment is completed, the shades of the abutment teeth, pontics, and tissue are selected, impressions are made, and the casts are mounted on an articulator. Resin denture teeth are waxed in the pontic region on the cast. The tooth arrangement is inserted in the mouth of the patient to verify the esthetics of the pontics. If the abutment teeth are not esthetically acceptable, the abutments may be prepared and restored with temporary crowns as part of the esthetic try-in of the pontic teeth. A plaster mold of the facial surfaces of the temporary crowns and denture teeth may also be made for use as a laboratory guide. The abutment teeth are prepared for ceramometal preparations. However, the axial wall of the abutments approximating the pontic must be reduced to allow space for joining the bar and the metal retainer. A final impression is made, a master cast is poured in stone, and the dies are prepared in the conventional manner.) The retainers are waxed and connected by a metal bar (Fig. 4) which is selected from a plastic guide depending on the curvature of the arch. The bar, which is positioned for the least restrictive path of insertion, should provide at least 1.5 mm of occlusal clearance and should be positioned in the same horizontal
Fig. 5. A, Retainers are cast to met; 1 bar. B, Framework is in place on cast. position as the center of the pontic teeth. The entire framework is then cast (Fig. 5), and porcelain is added to the retainers (Fig. 6). The framework is inserted in the m luth to verify the proximal, marginal, and occlusal rela ionships and the shade. If necessary, the porcelain may 3e contoured and stained at this point before it is glazed The area apical to the bar is then blocked out wii h wax, and an irreversible hydrocolloid impression is made with the restoration seated in the patient’s m#)uth. An investment bar of the same width as the framework bar is carefully positioned in the impression. It should extend into the teeth adjacent to the abutm:nt teeth, but it should only contact the same surface as the framework bar. The impression is poured in stone Then, using the plaster mold and the denture teeth arranged at the esthetic try-in appointment, the teeth ; .re waxed on the pontic sleeve which is placed on the investment bar (Fig. 7). The flange is festooned ant1 the removable pontic processed. At the insertion appointment, the filial restoration is adjusted before it is cemented and holne care instructions are given to the patient. The fri mework should
Fig. 6. Porcelain is fused to retainers.
Fig. 7. Pontic sleeve is shown inserted on investm&t bar.
not impinge on the tissue. The tissue surface of the bar may be ground and polished to relieve contact with the interdental papilla.* If there is too little retention in the pontic assembly, the framework is seated on the abutments and lightly adjusted with three-prong pliers. This is accomplished by placing the single prong of the three-prong pliers on the lingual (concave) side of the bar and the twin prongs on the labial (convex) side and gently pressing at 6 to 8 mm intervals. The pliers are reversed to lessen the retention. The framework should be cemented without the pontic on the bar to assure that the abutments are fully seated (Fig. 8).* ADVANTAGES
Compared to a conventional removable partial denture, the fixed-removable partial denture is more stable because it is totally tooth-borne and the occlusal forces are directed more along the long axes of the abutment teeth. The framework is constructed of ceramometal retainers which can be contoured and stained at the framework try-in appointment. Compared to a conventional fixed partial denture, the pontic teeth are arranged during the esthetic try-in appointment. The flange of the pontic assembly is contoured to improve comfort, esthetics, and phonetics, and to resist possible torque during function. Moreover, in contrast to conventional fixed partial dentures, the pontic assembly is removed to facilitate hygiene procedures and may be relined as the ridge resorbs. In a 12-year period, more than 25 fixed-removable partial dentures were made by the dentists of the Dental Activity at Fort Knox, Ky. These were found to be as durable as conventional fixed partial dentures. The only failures in the bar were due to inadequate soldering, and these failures were eliminated by casting the retainers directly to the bar. The wear and fracture
Fig. 8. Completed fixed-removable partial denture. incidence seen in the pontic assemblies were similar to those found with conventional removable partial dentures and were easily repaired. During this time, only a few adjustments with three-prong pliers were needed. While the retention is much greater than that of a typical unilateral partial denture, the fixed-removable partial denture should not be used for patients having occupations where the restoration may become jarred loose and swallowed or aspirated. However, with proper adjustments every 2 to 3 years this possibility is remote. SUMMARY The technique and rationale have been presented for the fixed-removable partial denture. ‘This type of denture has qualities of both the fixed partial denture and the removable partial denture and is indicated where the abutments would support a fixed partial denture but a severe defect is present in the edentulous space.
We would like to express our appreciation to Dr. Leo F. Broering, Chief, Removable Prosthodontic Service, U.S. Army Denta! Activity, Fort Knox, Ky., for his assistance in the preparation of this article. Long-term follow-up patients were completed at Fort Knox, Ky., by B. G. Lefler, Deputy Commander, Health Services Command, Fort Sam Houston, Tex.
J. A.: The Andrew Bridg’: A Clinical Guide. Covington, La., 1976, The Institute of Cosmetic Dentistry, pp 1-99. Johnston, J. F., Phillips, R.W., and Dyl .ema, R. W.: Modern Practice in Crown and Bridge Prosthod mtics, ed 3. Philadelphia, 1971, W. B. Saunders Co., pp 19~-198.
Henderson, D., and Steffel, V. L.: McCracken’s Removable Partial Prosthodontics. St. Louis, 1977, The C. V. Mosby Co.,
DR. MARK H. JOHNSON 769TH MEDICAL DETACHMENT
NEW YORK 09178
ARTICLES TO APPEAR IN FUTURE ISSUES A restorative resin foundation material William
F. Brady, D.M.D.,
H. Reisbick, D.M.D.,
In vivo comparison of a microfilled report Rella P. Christensen,
and a composite resin: A three-year
B.S., and Gordon J. Christensen,
Physical therapy as an adjunct to temporomandibular William
N. Danzig, D.D.S., and Arlyn
R. Van Dyke
Heat-processed acrylic resin provisional restorations: An in-office procedure S. Robert Davidoff,
Isolation of pathogenic microorganisms from dentures and denture-soaking containers of myelosuppressed cancer patients Louis G. DePaola,
D.D.S., M.S., and Glenn E. Minah,
D.D.S., M.S., Ph.D.
Transmucosal implants of dense hydroxylapatite C. de Putter, D.D.S., K. de Groot, Ph.D., and P. A. E. Sillevis Smitt, Ph.D., D.D.S.
The RPA clasp design for distal-extension removable partial denture; Charles M. Eliason, D.D.S., MS.
Clinical evaluation of two hundred patients with temporomandibula I joint syndrome Harold
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Functional contouring of the palatal vault for improving complete dentures Bal K. Goyal, D.M.D.,
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Palatal receptor contribution to and effects of palatal alteration on tagte acuity thresholds Ronald
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