Shimizu et al.

Int Chin J Dent 2006; 6: 79-81.

Repair of fractured lingual plate with a cast splinting device andmetal conditioners: A clinical report
Hiroshi Shimizu, DDS, PhD, and Yutaka Takahashi, DDS, PhD
Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College,Fukuoka, Japan
This article describes a repair procedure which allowed a removable partial denture with a fractured lingual plate
to be used as an interim prosthesis while a new one was fabricated. A groove was prepared continuously on thefractured lingual plate and denture base resin of the reassembled denture. A staple-shaped splint was cast andembedded in the groove with an adhesive resin. The resin around the splint was ground and a finish line wasprepared. Autopolymerizing repair resin was applied to the space. In this situation, the patient used the repaired
partial denture as an interim denture for 52 days until the new denture was completed. The present procedureusing a cast splint and metal adhesive system may be a meaningful contribution to repair a removable partial
denture with a fractured major connector without a dental solder with torch, electric or laser soldering technique.
However, this procedure should be restricted to situations requiring interim treatment during completion of anew denture. (Int Chin J Dent 2006; 6: 79-81.)
Key Words: adhesive system, fracture, interim denture, major connector, repair.

Introduction
When a metal major connector of a removable partial denture fractures, many clinicians immediately start tofabricate a new denture without repairing the old denture or making an interim prosthesis. This practice isinconvenient and stressful for patients who must do without serviceable dentures for an indefinite period of time
until the new denture is made. The laser welding technique1-4 is a versatile option for the repair of a dental metal
prosthesis, including the metal components of a removable partial denture.

However, the laser welding

technique has not come into wide use yet due to the high price of the laser processing apparatus. The proceduredescribed in this report will allow patients to retain the function of their existing dentures until new dentures arefabricated for them.

Clinical Report
A 42-year-old man presented with the chief complaint of masticatory disturbance due to the fracture of themandibular removable partial denture where the metal lingual plate had fractured along the external finish line(Fig. 1). The metal framework of the denture had been fabricated with cast cobalt-chromium alloy (Cobaltan,Shofu Inc., Kyoto, Japan). The maxillary dentition was natural teeth; none were missing. The thickness of theframework was sufficient at the fracture site, and no porosity was seen. When the patient was interviewed, heindicated that his hobby was fishing, and the denture fracture must have occurred when he bit on a particularly
tough metal fishing wire. One treatment option was to make a new denture without repair of the existing one,but the patient adamantly requested that the denture be repaired on the same day. Although the success of such arepair was not guaranteed, it was determined that the fractured denture could be repaired for use as an interimdenture.
To determine accurate fit, the denture was held together with sticky wax (New sticky wax, GC Corp., Tokyo,Japan) and small wooden sticks. Dental plaster (Plus-1, San-Esu Gypsum Co., Ltd., Osaka, Japan) was poured
into the mucosal surface of the reassembled denture. After the plaster hardened, a continuous groove wasprepared on the lingual plate and denture base resin (Fig. 2). A staple-shaped wax pattern (Violet Inlay Wax,79

Shimizu et al.

Int Chin J Dent 2006; 6: 79-81.

GC Corp.) of the groove was taken directly, invested (Cristobalite micro, GC Corp.), burned out and cast in asilver-palladium-copper-gold alloy (Castwell M.C. 12, GC Corp.) using a conventional spring-driven centrifugal
casting machine. This casting is termed the “splint” in this article. The splint was subjected to hardening heat
treatment, then its intaglio surface was airborne particle-abraded with 50 µm grain-sized alumina powder(Aluminous Powder WA 360, Pana Heraeus Dental Inc., Osaka, Japan) using an airborne particle abrasion unit
(Micro Blaster, Comco Inc., Burbank, CA, USA) and primed with a metal conditioner (V-Primer, Sun MedicalCo., Ltd., Moriyama, Japan).5-8 The bonding area of the lingual plate was also airborne particle abraded andprimed with another metal conditioner (Cesead II Opaque Primer, Kuraray Co., Ltd., Osaka, Japan).9,10 The
splint was then embedded in the groove with an adhesive luting resin (Super-Bond C&B ivory, Sun Medical Co.,Ltd.) (Fig. 3). After 24 hours, the resin around the splint was ground, and a definite finish line for the splint wasprepared by means of grinding the distal half of the splint. The new finish line was not considered to beconsistent with the original finish lines of the lingual plate. Next, the above-mentioned surface preparation ofthe metal was performed again (Fig. 4). Autopolymerizing denture repair resin (Unifast II, GC Corp.) wasapplied to the space. The repair surface was polished, and the entire repair procedure was finished (Fig. 5). The
fabrication of the new denture began immediately.

The patient wore the repaired denture as an interim

prosthesis until the splint on the temporary denture fractured along the newly prepared finish line after 52 days.
The day after the interim prosthesis broke, the new denture was completed.

123Fig. 1. Mandibular removablepartial denture with fractured
metal lingual plate.
Fig. 2. Staple-shaped preparation
for cast metal splint.
Fig. 3. Bonded cast metal splint.
Fig. 4. Preparations around repair
area and new finish line.
Fig. 5. Completed repair.

45Discussion
The denture repair described in this article is used only for the purpose of providing an interim denture while a
new one is being fabricated. The bond strength of dental alloy to adhesive luting cements or to denture baseresin is much lower than the tensile strength of removable partial denture alloys.11

Two metal adhesive

conditioners were chosen for the current situation. V-Primer is a conditioner for noble alloys that contains
VBATDT. V-Primer and 4-META/MMA-TBB opaque resin effectively bonded light-cured composite and asilver-palladium-copper-gold alloy.5 Cesead II Opaque Primer contains a phosphoric acid derivative (MDP) for
bonding to a base metal alloy. The efficiency of MDP was reported with regard to the bonding of cast80

Shimizu et al.

Int Chin J Dent 2006; 6: 79-81.

cobalt-chromium alloy.9
A staple-shaped cast splint with a finish line was used because a sufficient thickness of the denture base resinaround the splint seemed to be essential. However, the second denture fracture occurred when the splint brokealong the new finish line. Since the thickness of the metal is drastically different at the finish line, the probabilityof denture fracture increases because of the excessive stress concentrations. The finish line was considered to beunnecessary because the repaired denture had been used as an interim prosthesis until the completion of the newone. The splint should be very rigid and also bond well to the resin. A silver-palladium-copper-gold alloy wasused as the cast splint material because it was easy to handle. Examination of the secondary fracture indicatedthat the cause was not weak bonding between the metal and resin but the inferior strength of the splint. Based on
our experience, the use of a cobalt-chromium alloy instead of a silver-palladium-copper-gold alloy should extend
the lifetime of the repaired denture.
In summary, a procedure to repair a removable partial denture with a fractured metal lingual plate, whichallows the repaired denture to be worn temporarily using a cast splint and metal adhesive system was described.
The staple-shaped casting made from a silver-palladium-copper-gold alloy was airborne-particle abraded withalumina and primed with V-Primer. Half of the casting was bonded using Super-Bond C&B to the fractured
cobalt-chromium alloy connector primed with Cesead II Opaque Primer; the remainder of the casting wasembedded using an autopolymerizing acrylic repair resin. This repaired interim denture functioned well until it
fractured 52 days after repair. This procedure should be restricted to situations requiring interim treatment
during completion of a new denture.
Acknowledgment
The authors would like to thank Mrs. Jeanne Santa Cruz for editorial assistance.

References
1. Tambasco J, Anthony T, Sandven O. Laser welding in the dental laboratory: an alternative to soldering. J Dent Technol 1996;
13: 23-31.
2. Bertrand C, Le Petitcorps Y, Albingre L, Dupuis V. The laser welding technique applied to the non precious dental alloys
procedure and results. Br Dent J 2001; 190: 255-7.
3. Liu J, Watanabe I, Yoshida K, Atsuta M. Joint strength of laser-welded titanium. Dent Mater 2002; 18: 143-8.
4. Suzuki Y, Ohkubo C, Abe M, Hosoi T. Titanium removable partial denture clasp repair using laser welding: a clinical report. JProsthet Dent 2004; 91: 418-20.
5. Atsuta M, Matsumura H, Tanaka T. Bonding fixed prosthodontic composite resin and precious metal alloys with the use of avinyl-thiol primer and an adhesive opaque resin. J Prosthet Dent 1992; 67: 296-300.
6. Monya Y, Matsumura H, Atsuta M. A two-stage resin-bonded fixed partial denture seated in conjunction with post-extractionhealing of the alveolar socket: a clinical report. J Prosthet Dent 1998; 80: 4-8.
7. Matsumura H, Taira Y, Atsuta M. Adhesive bonding of noble metal alloys with a triazine dithiol derivative primer and anadhesive resin. J Oral Rehabil 1999; 26: 877-82.
8. Shimizu H, Takahashi Y. Fixed splinting device to be used without removing adjacent existing cast restorations. J Prosthet
Dent 1999; 82: 231-2.
9. Matsumura H, Tanaka T, Taira Y, Atsuta M. Bonding of a cobalt-chromium alloy with acidic primers and tri-n-butylboraneinitiated luting agents. J Prosthet Dent 1996; 76: 194-9.
10. Ohkubo C, Watanabe I, Hosoi T, Okabe T. Shear bond strengths of polymethyl methacrylate to cast titanium andcobalt-chromium frameworks using five metal primers. J Prosthet Dent 2000; 83: 50-7.
11. Anusavice KJ. Phillips’ science of dental materials. 11th ed. St. Louis: Saunders; 2003. p.563-620.

Correspondence to:Dr. Hiroshi Shimizu
Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College2-15-1, Tamura, Sawaraku, Fukuoka 814-0193, Japan
Fax: +81-92-801-0513 E-mail: simizuh1@college.fdcnet.ac.jp
Received March 9, 2006. Accepted April 17, 2006.
Copyright ©2006 by the International Chinese Journal of Dentistry.

81