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Int Chin J Dent 2008; 8: 29-32.

A three-unit mandibular resin-bonded fixed partial dentureseated after closing anterior open spaces: A clinical report
Hideo Matsumura, DDS, PhD,a,b Yumiko Hosoya, DDS, PhD,c Naomi Tanoue, DDS,PhD,d and Hiroyasu Koizumi, DDS, PhDa,bab

Department of Fixed Prosthodontics, and Division of Advanced Dental Treatment, Dental Research
cCenter, Nihon University School of Dentistry, Tokyo, Nagasaki University Graduate School ofdBiomedical Sciences, and Nagasaki University Hospital of Medicine and Dentistry, Nagasaki, JapanThis clinical report describes a resin-bonded fixed partial denture (RB-FPD) seated with the aim of replacing acongenitally missing lateral incisor as well as for permanent retention after minor teeth movement. A RB-FPDframework was cast from silver-palladium-copper-gold alloy (Castwell M.C. 12), and the pontic was veneered
with indirect composite material. The RB-FPD was treated with a metal priming agent (Alloy Primer), andbonded with a composite luting agent (Panavia Fluoro Cement). After an observation period of seven years andsix months, the FPD was functioning satisfactorily without periodontal rebound. The materials and technique
reported here are applicable as an option for fixed prosthodontic treatment after closing anterior open spaces inadolescent patients. (Int Chin J Dent 2008; 8: 29-32.)
Key Words: adhesive, alloy, primer, resin-bonded fixed partial denture, retainer.

Introduction
Replacement of missing teeth in the anterior region is important for recovering tooth anatomic form, esthetics,mastication, pronunciation and other oral functions. After orthodontic alignment of the dentition, it is necessary
for patients to wear retainers for stabilizing their teeth and periodontal tissues. Both removable and fixed
retainers are used according to the location and number of teeth to be retained. Among them, resin-bonded fixed
partial dentures (RB-FPDs) with minimal tooth reduction are applicable and acceptable as permanent retainers
after orthodontic treatment as well as for replacement of missing teeth.
Noble metal alloys are more desirable as FPD frameworks than base metal alloys because of their adaptation
to abutments. Moreover, a single liquid primer that contains a thione monomer (Alloy Primer, Kuraray MedicalInc., Tokyo, Japan) has been introduced for bonding dental noble metal alloys.1Although a number of

prosthodontic applications of the Alloy Primer material and composite luting agents (Panavia systems, Kuraray
Medical Inc.) have been reported, only limited information is available about the long-term clinical performanceof the Kuraray metal bonding systems.2-4 This clinical report describes the 7.5-year clinical performance of aRB-FPD seated in the mandibular dentition for recovering esthetics and oral function after closing open spaces.

Clinical Report
A 16-year-old female patient presented with esthetic and functional disturbances as a result of congenitally
missing right mandibular lateral incisor. The patient had undergone orthodontic treatment previously and waswearing a removable retainer (Fig. 1). Several treatment options were therefore proposed: 1) single-tooth
implant; 2) RB-FPD without tooth reduction; 3) direct-bonding of an artificial pontic; and 4) a removable partial
denture similar to the removable retainer. The patient chose the second of the proposed techniques. The
procedure was then explained in detail and consent was obtained from the patient and her mother.
Centric occlusion, lateral mandibular movement, and anterior guidance were examined intraorally witharticulating paper and extraorally using a stone cast. After examination of the maxillo-mandubular relation, theareas to be bonded were determined.

Reduction of enamel was judged as unnecessary.

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Int Chin J Dent 2008; 8: 29-32.

prospective bonding area of the retainers was extended as much as possible within the lingual and proximal
surfaces of the abutments.

1Fig. 1.
Fig. 2.

2

A radiograph with the retainer used for retention after orthodontic treatment.
Pre-operative facial view.

3

4Fig. 3.
Fig. 4.

Facial view of the RB-FPD seated with the Alloy Primer and Panavia Fluoro Cement system.
Occlusal view of the RB-FPD.

Fig. 5.
Fig. 6.

Facial view of the RB-FPD two years after cementation.
Occlusal view of the RB-FPD two years after cementation.

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6An impression of the entire mandible was made with addition silicone elastomeric materials (Exafine Puttyand Injection, GC Corp., Tokyo, Japan) using a stock tray. Die stone (Fuji Rock, GC Corp.) was poured into theimpression, and a working cast was prepared. The stone cast was then mounted in a semi-adjustable articulator
with an opposing cast. The pattern of the retainer and pontic was fabricated using an inlay wax material (Inlay30Matsumura et al.

Int Chin J Dent 2008; 8: 29-32.

Wax, GC Corp.), and invested with a mold material (Cristobalite Micro, GC Corp.). An FPD framework
consisting of two retainers and a pontic, was cast from silver-palladium-copper-gold alloy (Castwell M.C. 12,GC Corp.). The pontic was of sanitary type, the buccal surface of which was veneered with an indirectcomposite material.
On the second appointment, the completed FPD was tried-in. The inner surfaces of the retainers wereair-abraded immediately before bonding, with 50- to 70-µm grain sized alumina (Hi-Aluminas, Shofu Inc.,Kyoto, Japan) using an airborne particle abrader (Micro Blaster MB102, Comco Inc., Burbank, CA, USA), andtreated with a single liquid primer designed for both noble and base metals (Alloy Primer). The lingual enamelsurfaces of the abutment were etched with 40% phosphoric acid gel (K-Etchant, Kuraray Medical Inc.), washedwith water, and air-dried. The FPD was then seated with Panavia Fluoro Cement adhesive (Kuraray MedicalInc.). The patient entered a maintenance program and was examined twice every year (Figs. 2-6). After anobservation period of seven years and six months, the RB-FPD was still functioning satisfactorily.

Discussion
It is necessary for patients to use retainers after minor tooth movement. The influence of destabilizing factors,i.e., periodontal rebound, subsequent mandibular growth, and resting periodontal tissue pressure can be
minimized with either removable or bonded retainers. Probability of detachment of retainers is greater than thatof FPDs. This is due to the continuous rebounding force applied to the abutment roots. The composite veneer ofthe pontic was somewhat extended to the proximal surfaces and incisal edges of the abutment teeth with theintention of stabilizing the mandibular anterior dentition. An ideal cervical contour could also not be provided tothe pontic so as to allow cleaning with an interdental brush or Super-floss. As a result, the anatomic form of thepontic was not highly aesthetic. The patient and her mother, however, were satisfied with no-reduction of theabutments rather than other factors.
A noble metal adhesive system (Alloy Primer and Panavia Fluoro Cement) combined with enamel etching
using phosphoric acid was applied in the patient to achieve durable bonding between the FPD retainers andabutments. This is a simple and tooth-conservative technique, which is especially useful for adolescent patients
because tooth attrition is not apparent, and the clinical crown/root ratio is unpredictable at this age. Although
regular check-ups are essential, the techniques and materials described in this clinical report may be useful as a
post-orthodontic prosthodontic treatment option in adolescent patients.
Acknowledgments
This clinical report associated with adhesive bonding of dental casting alloys is supported in part by Sato Fund, Nihon
University School of Dentistry (2007), and by Grant from Dental Research Center (A), Nihon University School of Dentistry(2008).

References
1. Matsumura H, Shimoe S, Nagano K, Atsuta M. Effect of noble metal conditioners on bonding between prosthetic composite
material and silver-palladium-copper-gold alloy. J Prosthet Dent 1999; 81: 710-4.
2. Matsumura H, Nakamura M, Tanoue N, Atsuta M. Clinical evaluation of an urethane tetramethacrylate-based composite
material as a prosthetic veneering agent. J Oral Rehabil 2000; 27: 846-52.
3. Hagiwara Y, Matsumura H, Tanaka S, Woelfel JB. Single tooth replacement using a modified metal-ceramic resin-bonded
fixed partial denture: a clinical report. J Prosthet Dent 2004; 91: 414-7.
4. Botelho MG, Leung KC, Ng H, Chan K. A retrospective clinical evaluation of two-unit cantilevered resin-bonded fixed partialdentures. J Am Dent Assoc 2006; 137: 783-8.

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Correspondence to:Dr. Hiroyasu Koizumi
Department of Fixed Prosthodontics, Nihon University School of Dentistry
1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
Fax: +81-3-3219-8351 E-mail: koizumi@dent.nihon-u.ac.jp
Received February 10, 2008. Accepted May 31, 2008.
Copyright ©2008 by the International Chinese Journal of Dentistry.

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