A Technique for Retrofitting a Metal Ceramic Crown to an Attachment-Retained Removable Partial Denture: A Clinical Report Bulent Uludag, DDS, PhD, Fehmi Gonuldas, Emre Tokar, DDS, & Volkan Sahin, DDS, PhD Department of Prosthodontics, Faculty of Dentistry, University of Ankara, Ankara, Turkey

Keywords Precision attachment; attachment-retained dentures. Correspondence Bulent Uludag, Department of Prosthodontics, Faculty of Dentistry, University of Ankara, Besevler Ankara 06500, Turkey. E-mail: [email protected] The authors deny any conflicts of interest. Accepted March 7, 2014

Abstract In dental applications, precision attachments have been used to retain removable partial dentures (RPDs) for several decades. Various types of extracoronal attachments are commonly used in combination with fixed partial dentures and RPDs to achieve retention and stability. Fracture of the framework, fracture of the roots or teeth, and irretrievable decrease of retention are common reasons for a failed attachment-retained RPD. Another complication of metal ceramic crowns with precision attachment is decementation of the crowns. When fixed components of the attachment-retained RPD fail, the traditional treatment approach requires remaking both the fixed and removable components of the attachment-retained RPD. This technique describes retrofitting of a metal ceramic crown to a resilient attachment-retained RPD.

doi: 10.1111/jopr.12204

In dental applications, precision attachments have been used to retain removable partial dentures (RPDs) for several decades.1,2 Generally, clasps, adhesive attachments, crowns, and fixed partial dentures (FPDs) with intra- or extracoronal attachments, telescopes, root caps, and/or prefabricated interradicular retainers provide that retention for combinations of FPDs and RPDs.3,4 Various types of extracoronal attachments are commonly used in combination FPDs and RPDs to achieve retention and stability.2 Framework fracture, fracture of the roots or teeth, and irretrievable decrease of retention are common reasons for a failed attachment-retained RPD. Another complication of metal ceramic crowns with precision attachment is the decementation of the crowns.3,5,6 Although retrofitting of crowns to existing RPDs has been well documented, including fabrication of direct resin copings on the abutment teeth, making resin replicas of the clasp assemblies,7-20 or using CAD/CAM technology,21,22 no information regarding retrofitting of crowns to existing attachment-retained RPDs has been documented. Common clinical protocol requires remaking both fixed and removable components of an attachment-retained RPD. This article describes a method whereby a metal ceramic crown can be retrofitted to a resilient attachment-retained RPD.

Clinical report A 70-year-old man was referred to the Department of Prosthodontics, Faculty of Dentistry, University of Ankara (Ankara, Turkey) for evaluation. In the initial clinical exam-

ination, attachment-retained distal extension RPDs were noted for both dental arches. The mandibular RPD was supported by mandibular left and right canines. The metal ceramic crown of the mandibular right canine was missing. The patient stated that the RPD had been in service for 2 years without any complaints. The patient had not experienced any previous decementation of the metal ceramic crown on the mandibular right canine, which was noted to be sound with no clinically detectable mobility. The RPDs were observed to have acceptable occlusion and esthetics. No periodontal or periapical lesions were present in the radiographic examination. Previous dental records were obtained from the previous dental office where the existing RPDs were fabricated. These records indicated that the attachment system used to retain the RPD was the resilient rk-1 attachment system (rk-1; Kargı Sa˘glık, Bursa, Turkey; Fig 1). Castable extracoronal rk-1 attachments are resilient and permit a hinging movement limited to 17° of the distal extension RPD. These attachments have plastic patrices and matrices. The castable patrix is attached to the crown pattern with a paralleling mandrel, and the matrix is incorporated into the cast framework using inserting tools. Because current clinical knowledge requires splinting of at least two terminal abutment teeth to retain an extensionbase, attachment-retained RPD,23 the patient was offered a new treatment plan including remaking of a new attachmentretained mandibular RPD after tooth preparation of the remaining mandibular arch. The patient rejected the treatment plan because of the prolonged treatment period and asked about the

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Figure 3 Mandibular prosthesis impression. Figure 1 View of the patrix and matrix of the rk-1 castable attachment.

Figure 2 Intraoral view of the denture in the mouth.

Figure 4 Resin pattern and castable attachment patrix assembly on the master model.

possibility of retrofitting of the lost metal ceramic crown to the existing RPD. A new treatment plan, including fabrication of a resin pattern and castable attachment patrix assembly to form the substructure of the metal ceramic crown on the definitive cast, was developed and accepted by the patient. Impression of the maxillary arch was made with irreversible hydrocolloid (CA37; Cavex Holland B, Haarlem, The Netherlands) using a stock tray (Teknik Dis Deposu, Istanbul, Turkey). Low-viscosity poly(vinyl siloxane) impression material (Mucosa Xantopren; Kulzer, Hanau, Germany) was applied to the intaglio surfaces of the mandibular RPD, which was placed intraorally. The final seat of the mandibular RPD was verified by visually inspecting the position of the left reciprocating arm of the RPD with the milled lingual surface of the same attachment-retained metal ceramic crown on the mandibular left canine (Fig 2). The patient was instructed to apply slight occluding force in maximum intercuspal position. Low-viscosity elastomeric impression material (Speedex; Coltene/Whaledent Inc, Cuyahoga Falls, OH) was injected around the mandibular right canine, and a pick-up impression of the mandibular RPD was made in a rigid stock tray with heavy-body elastomeric impression material (Speedex; Fig 3). Type IV stone (BEGO, Bremen, Germany) was poured into the impression. After forming a resin pattern to fabricate the substructure of the metal-ceramic crown (Fig 4), a castable attachment patrix 2

Figure 5 View of attachment matrix in the mandibular RPD.

was incorporated with the matrix on the RPD framework (Figs 5 and 6). The castable attachment patrix was incorporated in the resin pattern with sticky wax (Keystone Industries GmbH, Singen, Germany). The resin pattern and castable attachment patrix assembly was cast with a chrome-cobalt alloy (Biosil F; Degudent, Hanau, Germany; Fig 7) and was verified intraorally (Fig 8). Veneering porcelain was applied with conventional techniques and evaluated intraorally. The metal ceramic crown

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Figure 6 Resin pattern and castable attachment patrix assembly attached to the matrix.

A Technique for Retrofitting a Metal Ceramic Crown

Figure 9 Intraoral view of the metal ceramic crown.

Figure 7 Cast metal substructure of attachment-retained crown. Figure 10 Intraoral view of the attachment-retained crowns.

Figure 8 Intraoral view of the cast metal substructure.

with rk-1 attachment was finished according to manufacturer’s recommendations (Figs 9–11).

Discussion Attachment-retained RPDs may fail due to decementation of the fixed components, which may be associated with geometry of the tooth preparations as well as the geometry of the restorations and improper cementation techniques. When the fixed components of an attachment-retained RPD fail, the tra-

Figure 11 Intraoral view of the mandibular RPD.

ditional treatment approach requires remaking of both fixed and removable components of the attachment-retained RPD.6 This clinical report describes retrofitting of a metal ceramic crown to a resilient attachment-retained RPD by using a resin pattern and castable attachment patrix assembly to form the substructure of the metal ceramic crown. Advantages of this technique include decreased chair time and treatment cost, as well as increased

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patient satisfaction compared to remaking of both fixed and removable components of the attachment-retained RPD. The increased technical sensitivity is a disadvantage of this technique. Proper impression techniques and the careful incorporation of the patrix assemblies are the key factors determining the outcome of the described technique. Well-documented clinical studies are required to determine long-term results of this technique.

Summary Several reasons for failure of combination FPDs and RPDs include fracture of the framework, fracture of the roots or teeth, irretrievable decrease of retention, and decementation of the fixed components, which may eventually be lost. Although retrofitting of crowns to existing RPDs has been well documented, no information regarding retrofitting of crowns to existing attachment-retained RPDs has been documented. Common clinical protocol requires remaking of both fixed and removable components of an attachment-retained RPDP. This article describes a method whereby a metal ceramic crown can be retrofitted to a resilient attachment-retained RPD.

References 1. Uludag B, Sahin V, Polat S: Replacement of a lost removable partial dental prosthesis using ball-attachment analogs: a clinical report. J Prosthodont 2011;20:488-490 2. Owall B: Precision attachment-retained removable partial dentures. Part I. Technical long-term study. Int J Prosthodont 1991;4:249-257 3. Uludag, B, Polat S, Sahin V, et al: A technique for fabrication of an extracoronal attachment-retained removable partial denture to fit an existing fixed partial denture. J Prosthodont 2012;21: 138-140 4. Zitzmann NU, Rohner U, Weiger R, et al: When to choose which retention element to use for removable dental prostheses. Int J Prosthodont 2009;22:161-167 5. Owall B: Precision attachment-retained removable partial dentures. Part 2. Long-term study ball attachments. Int J Prosthodont 1995;8:21-28 6. Owall B, J¨onsson L: Precision attachment-retained removable partial dentures. Part 3. General practitioner results up to 2 years. Int J Prosthodont 1998;11:574-579

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7. Killebrew RH: Crown construction for broken down partial denture abutments. J Prosthet Dent 1961;11:93-94 8. Barrett DA, Pilling LO: The restoration of carious clasp-bearing teeth. J Prosthet Dent 1965;15:309-311 9. Ewing JE. The construction of accurate full crown restorations for an existing clasp by using a direct metal pattern technique. J Prosthet Dent 1965;15:889-899 10. Warnick ME: Cast crown restoration of a badly involved abutment to fit an existing removable partial denture. Dent Clin North Am 1970;14:631-644 11. Goldberg AT, Jones RD: Constructing cast crowns to fit existing removable partial denture clasps. J Prosthet Dent 1976;36:382-386 12. Hill GM: Construction of a crown to fit a removable partial denture clasp. J Prosthet Dent 1977;38:226-228 13. Teppo KW, Smith FW: A technique for restoring abutments for removable partial dentures. J Prosthet Dent 1978;40:398-401 14. Tallents RH: Crown construction to fit an existing removable partial denture. Gen Dent 1985;33:48-50 15. Gordon SR: Making a provisional crown under a clasp of an existing removable partial denture. J Prosthet Dent 1992;68:556-557 16. Silberman DM: An indirect procedure for making a crown under an existing partial denture. J Prosthet Dent 1993;69:631-633 17. Hansen CA, Russel MM: Making a crown fit accurately under an existing removable partial denture clasp assembly. J Prosthet Dent 1994;71:206-208 18. Livaditis GJ: Fabricating abutment crowns for existing removable partial dentures using custom resin clasp analogs. J Prosthet Dent 1998;80:619-629 19. Helvey GA: Retrofitting crowns to an existing removable partial denture clasp: a simple technique. J Prosthet Dent 2002;87:399-402 20. Fujisawa M, Adachi K, Tsuruta S, et al: A procedure for fitting a fixed partial denture to an existing removable partial denture. J Prosthet Dent 2004;91:392-394 21. Yoon T, Chang W: The fabrication of a CAD/CAM ceramic crown to fit an existing partial removable dental prosthesis: a clinical report. J Prosthet Dent 2012;108:143-146 22. Marchack BW, Chen LB, Marchack CB, et al: Fabrication of an all-ceramic abutment crown under an existing removable partial denture using CAD/CAM technology. J Prosthet Dent 2007;98:478-482 23. El Charkawi HG, El Wakad MT: Effect of splinting on load distribution of extracoronal attachment with distal extension prosthesis in vitro. J Prosthet Dent 1996;76:315-320

C 2014 by the American College of Prosthodontists Journal of Prosthodontics 00 (2014) 1–4 

A technique for retrofitting a metal ceramic crown to an attachment-retained removable partial denture: a clinical report.

In dental applications, precision attachments have been used to retain removable partial dentures (RPDs) for several decades. Various types of extraco...
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