SHIMIZU, HABU, AND YANAGIDAINT CHIN J DENTStabilization by splinting of an endodontically treated premolar and aminimally reduced vital canine with a resin-bonded cast retainer: Aclinical report
Hiroshi Shimizu, DDS, PhD,a Tetsuya Habu, DDS, PhD,a and Hiroaki Yanagida,DDS, PhDb
aDivision of Removable Prosthodontics, Department of Oral Rehabilitation,
Fukuoka Dental College, Fukuoka, Japan, and bGeneral Dentistry Department,
Nagasaki University Hospital of Dentistry, Nagasaki, Japan
This clinical report describes a technique to stabilize a loosened tooth by splinting with a minimallyreduced vital adjacent tooth using a cast retainer and a metal adhesive system. The retainer made from asilver-palladium-copper-gold alloy was air-abraded with alumina, primed with a metal conditioner(V-Primer), and bonded to the etched abutments with an adhesive resin (Super-Bond C&B). The retainer isfunctioning for more than five years, and the result indicates the effectiveness of the current technique.
(Int Chin J Dent 2002; 2: 121-125.)
Keywords: adhesive resin, intact tooth, minimal reduction, primer, splint.

INTRODUCTION
Splinting is considered to be effective for stabilization of dentition with mobility caused by periodontal
diseases and traumatic injury. Due to the relatively low dental caries activity of patients with chronic
marginal periodontitis, clinicians are frequently requested to fix multiple intact teeth. One of the mostreliable fixation techniques is placement of a cast splint device consisting of multiple full coverage
restorations, although considerable tooth preparation is necessary with this procedure. The application ofresin-bonded retainers with minimal tooth reduction, a method combining enamel etching and the use ofunfilled resin adhesive, was reported thereafter.1-3 Although bonding to enamel of bonding agents iscurrently established, the durability of bond to noble metal alloys of resin-based luting agent remains
insufficient. A new metal conditioner capable of bonding noble metal alloys (V-Primer) was reported in
the past decade. Both laboratory and clinical evaluation demonstrated the effectiveness of the primer.4-6
However, only limited information is available about the application of the new bonding system to toothfixation.5 This clinical report describes a technique for splinting a mobile tooth adjacent to an intact toothusing a cast retainer and a noble metal adhesive system.

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CLINICAL REPORTA fifty-year-old female patient presented with a chief complaint of masticatory disturbance caused by
missing left maxillary molars and mobility of the first premolar. Examination revealed moderate toothmobility of the first premolar, and an X-ray photograph demonstrated considerable loss of bone support,
especially in the distal area (Fig. 1). The premolar therefore seemed unable to serve as a clasped tooth inits current condition. Before starting periodontal and prosthodontic treatments, a splinting technique withminimal vital tooth reduction was proposed, and the patient’s consent was obtained.

Fig. 1. Radiograph of a maxillary left first premolar with moderate mobility.
Fig. 2. Preparation of the first premolar to be used as a full cast restoration abutment. Occlusal
color indicator demonstrates the cuspid protected articulation of the patient.

Fig. 3. Removable die of the maxillary canine. Preparation was limited only in the restricted area
which should not contact the antagonistic tooth in any position of the mandible.
Fig. 4. Completed splinting device made from a silver-palladium alloy. Retentive structure isseen at the canine retainer.
After completion of periodontal therapy, prosthodontic treatment for the first premolar was started.
Composite core build-up material combined with a prefabricated post was bonded to the root canal of thepremolar. The abutment was prepared for a full cast restoration (Fig. 2). Next, a cavity was prepared on
the linguodistal surface of the adjacent intact canine. The canine was vital, and the bone support was122

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sufficient to receive the applied occlusal force. Reduction was limited to the restricted area, which should
not contact the antagonist in any position of the mandible. In addition, a vertical groove at the proximal
plane and a pinhole in the lingual rest seat were sunk for mechanical retention (Fig. 3). An impression wasmade with a silicone elastomeric material and a working cast was prepared. A wax pattern for the two-unit
splinting device was fabricated, sprued, and invested into a cristobalite mold material.

Asilver-palladium-copper-gold alloy (Castwell M.C. 12, G-C Corp., Tokyo, Japan) was cast in the mold bymeans of a centrifugal casting machine. The casting was adjusted and polished (Fig. 4).

Fig. 5. Occlusal view of the casting bonded with the V-Primer-Super Bond adhesive system (left).
Fig. 6. Occlusal view after five years of seating. Facial surface of the premolar has been
modified using a resin-bonded overcasting.

Fig. 7. The premolar is also functioning as a clasped tooth.
Fig. 8. Radiograph five years after splinting. The level of the alveolar bone has recovered ascompared with the pre-operative level.
The device was tried-in, and the surface to be bonded was air-abraded with 50 µm grain-sized aluminumoxide (Aluminous Powder WA 360, Pana Heraeus Dental Inc., Osaka, Japan) using a grit blaster (MicroBlaster MB102, Comco Inc., Burbank, CA, USA).

Shortly before insertion, a metal priming agent(V-Primer, Sun Medical Co., Ltd., Moriyama, Japan) was applied to the retainer with a sponge pellet. Theabutment teeth were cleaned and etched with 37% phosphoric acid. The device was then seated with an123

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adhesive luting agent (Super-Bond C&B ivory, Sun Medical Co., Ltd.; Fig. 5).
After insertion of the splinting device, the patient followed a regular check-up program. Although thefacial surface of the premolar restoration was replaced with an overcasting in response to a request from thepatient, the two-unit fixation casting is functioning for more than five years (Figs. 6 and 7). Fig. 8 shows aradiograph taken five years after splinting. The level of the alveolar bone has recovered considerably ascompared to the pre-operative level.

DISCUSSION
A splinting technique for lower anterior teeth with no or minimal reduction was described by Rochette.1
Improvement in adhesive techniques increased bond strengths between retainers and adhesive resin luting
agents.6 A long-term follow-up study, however, indicated that mobility of the abutment teeth was one ofthe decisive prognostic factors for success of resin-bonded fixed partial dentures.2

Furthermore,resin-bonded fixed partial denture without any retentive preparation form on each abutment tooth resulted
in a significantly higher failure rate.3
Considering these results, application of a splinting device without tooth preparation seemed inadequate,
although the concept of minimal intervention7 is important for the intact teeth. Retentive structures werereluctantly applied in the current case to extend both the life of the premolar abutment and the service
period of the splinting device.
The advantages of the adhesively retained splinting technique are 1) higher probability of achieving an
optimal result, 2) minimal tooth reduction, 3) low possibility of damage to the pulp, 4) simple technicalprocedure, and 5) preservation of the patient’s innate occlusal function. One of the disadvantages of thetechnique has been insufficient bonding between resin-based luting agents and noble metal alloys, but thisdifficult problem seems to have been overcome by the development of thione primers.4-6 As shown in Figs.
6 through 8, the splinting device is satisfactorily functioning, and the premolar is surviving as the clasped
tooth without any clinical problem. The clinical results indicate that this device has eliminated an enhanced
rate of periodontal destruction, promoted remodeling of the alveolar bone, and maintained functionalstability.

This method is therefore suitable for construction of a fixed splinting device especially whenproper stabilization must include an intact tooth.

CONCLUSION
A fixed splinting device with a unique abutment preparation design was reported. The longevity of thedevice was facilitated with the use of a noble metal adhesive system.

REFERENCES
1. Rochette AL. Attachment of a splint to enamel of lower anterior teeth. J Prosthet Dent 1973; 30: 418-23.
2. Probster B, Henrich GM. 11-year follow-up study of resin-bonded fixed partial dentures. Int J Prosthodont 1997; 10:259-68.

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3. Behr M, Leibrock A, Stich W, Rammelsberg P, Rosentritt M, Handel G. Adhesive-fixed partial dentures in anterior andposterior areas. Results of an on-going prospective study begun in 1985. Clin Oral Investig 1998; 2: 31-5.
4. Matsumura H, Atsuta M. Repair of an eight-unit fixed partial denture with a resin-bonded overcasting: a clinical report. JProsthet Dent 1996; 75: 594-6.
5. Shimizu H, Takahashi Y. Fixed splinting device to be used without removing adjacent existing cast restorations. JProsthet Dent 1999; 82: 231-2.
6. Matsumura H, Kamada K, Tanoue N, Atsuta M. Effect of thione primers on bonding of noble metal alloys with anadhesive resin. J Dent 2000; 28: 287-93.
7. Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimal intervention dentistry--a review. FDI Commission Project1-97. Int Dent J 2000; 50: 1-12.

Reprint request to:
Dr. Hiroshi Shimizu
Division of Removable Prosthodontics, Department of Oral Rehabilitation
Fukuoka Dental College2-15-1, Tamura, Sawara-ku, Fukuoka 814-0193, Japan
Fax: +81-92-801-0513
E-mail: simizuh1@college.fdcnet.ac.jp

Received on April 30, 2002. Revised on July 5, 2002. Accepted on July 16, 2002.
Copyright ©2002 by the Editorial Council of the International Chinese Journal of Dentistry.

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