Anterior Fiber-Reinforced Fixed Partial Dentures Revisited

INTRODUCTION
Several techniques have been reported on in the literature related to the treatment of anterior partial edentulism and its effects on aesthetics and function.¹ Patients with single-tooth loss can be treated with osseointegrated implants, fixed prosthodontics, removable partial dentures, and fiber-reinforced polymer bridges (FRPBs). Actually including minimally invasive dentistry protocols into daily practice can be helpful, preserving sound dental tissue using a more conservative approach.² FRPBs are indicated for interim restorations, and in certain cases, long-term restorations.³ A protocol for the anterior fiber-reinforced composite restoration was described in 1993, presenting the advantages of avoiding preparations on the sound teeth adjacent to the edentulous space.⁴ Since then, more cases have been reported in the literature on FRPBs. Throughout time, this technique has become more well known and improved.⁵ In 2001, Antón-Radigales⁴ presented results with cases that had been followed for 10 years postoperatively. FRPBs can be made intra- or extraorally,⁶ and several authors have described a direct technique for their fabrication. Also, a technique incorporating the manufacture of plaster models for planning restorations indirectly has been published.⁷ Other authors have described various materials for the pontic area (tooth, ceramic, or denture teeth stock) and for the adjacent teeth (ceramics, resin, or metal).⁸

This article presents a simple but important change in the technique for the fabrication of an FRPB. It presents a case with a 2-year follow-up that describes a mixed technique which uses a model for the indirect fabrication of the cervical area of the pontic with the purpose of obtaining an individualized anatomic design.

CASE REPORT
A 17-year-old female presented, requesting treatment for impacted right and left maxillary canines (teeth Nos. 6 and 11) and to then address her aesthetics and function. After lingual ortho­dontic therapy (using the Lingual Straight Wire Technique), the impacted canines were surgically removed. The teeth were aligned through ortho­dontic treatment to allow for ideal design of restorations and optimal occlusal relationships (Figures 1 and 2).

Figure 1. Retracted anterior pre-op photo.

After the postsurgical healing period, alginate impressions were taken with a stock rim-lock tray and poured with Type IV plaster. Next, both canines were waxed to full contour on the model. A .040-in thermo-formed splint (Invisacryl) was fabricated and delivered to create the desired soft-tissue sites in the pontic areas. The splint served for 6 weeks as temporary restoration.

Once the soft tissue was ready to go, complete isolation of the teeth was achieved with a rubber dam. The aprismatic enamel on the palatal and proximal surfaces to the edentulous space was roughened with a coated aluminum oxide disc (Sof-Lex Extra Thin XT 2382C [3M]). The enamel on the interproximal surfaces were etched with 37% phosphoric acid gel (Scotchbond Universal Etchant Gel [3M]) (Figure 3), and then a 4th generation adhesive system (OptiBond FL [Kerr]) was used according to the manufacturer’s directions.

Figure 3. Etching procedure done with proper rubber dam isolation.

Figure 4. Fluid resin composite (Filtek Supreme XTE Flow [3M]) on the surfaces of the fiber in contact with the abutments, placed from palatal to buccal.

Figure 5. (a) Palatal fiber-reinforced polymer (FRP). (b) Intermediate composite layer. (c) Additional buccal FRP is fixed with (d) a buccal layer of composite.

Figure 6. The double y-shaped FRP bridge framework.

Figure 7. Palatal surface of the fiber was covered with a microhybrid composite (shade A3 Universal Dentin; Z100 [3M]) and light-cured for 40 seconds.

Figure 8. Lateral view of the 3.0-mm window.

A 21.0-mm length of FRP (Multi Fibre Bridge [DEI españa]) was cut with scissors. Although the fiber comes from the manufacturer already impregnated, a fluid resin composite (Filtek Supreme XTE Flow [3M]) was placed from palatal to buccal on the surfaces in contact with the abutments (Figure 4). The FRP was attached and light-cured (Elipar [3M]) for 40 seconds. The framework fabrication steps are demonstrated in Figure 5. The final shape/design of the framework is shown in Figures 6 and 7.

The palatal surface of the fiber was covered with a microhybrid composite resin in shade A3 Universal Dentin (Z100 [3M]) and light-cured for 40 seconds. Excess composite was carefully removed using a fine-grain diamond (863.012.314F [AXIS Dental]) at a low speed (10,000 rpm) and a 3.0-mm dimension window, cut into fiber-composite structure in an apico-incisal direction, was made (Figure 8).

On the soft-tissue model, in the edentulous areas of each canine, the cervical area of the pontics was created anatomically with a nanocrystalline composite (shade A1; ESTELITE SIGMA QUICK [Tokuyama Dental America]) (Figure 9).

Figure 9. Soft-tissue model with anatomically designed pontic sites.

Figure 10. Fitting the pontics to the mucosa.

Figure 11. Checking/flossing the interproximal areas to ensure good oral hygiene could be maintained; and, the final intraoral result.

In order to ensure excellent intraoral fit of the pontic, the rubber dam was removed, then the restoration was pressed onto the soft tissue, joining the pontic to the substructure with a flowable composite (Figure 10). After waiting 3 minutes for the tissues to revascularize, the building of a polychromatic and anatomically shaped restoration was started by first placing a layer of opaque dentin (Dentin A3; Filtek Supreme XTE). Next, a thin layer of enamel composite (Body A2; Filtek Supreme XTE) was added and characterized with a masking agent (Symphony [3M]). Finally, the surface of the pontic was covered with a microfilled composite (shade WE; ESTELITE SIGMA QUICK). Finally, finishing and polishing was done (Figure 11). The patient was pleased with the excellent aesthetic results (Figures 12 and 13).

DISCUSSION
Several procedures have been indicated to replace anterior missing teeth. Direct composite restorations are an option to preserve biological tissue of the adjacent teeth in aesthetic anterior areas.⁹ Implant-supported and implant-retained restorations are well indicated; however, issues of time and budget can be obstacles for the patient. Fast, successful, and reliable techniques using adhesive procedures have been applied during the last 3 decades.10 Fixed partial dentures have been documented as an option to replace missing anterior teeth with minimally invasive preparations. Standard bridge or cantilevered designs are alternative treatment options;^11-13 however, additional laboratory procedures (ceramic layering) can present time-related challenges. Chairside CAD/CAM procedures are a good option to make one-appointment restorations, but the interconnector zone requires at least 4.0 mm space to make long-lasting restorations.¹⁴

Figure 12 and 13. Anterior and lateral views of the final restorations at a 2-year follow-up visit.

In this article, the authors have presented a modification on the method of reinforcing glass fiber and composite structure using the “double y” technique in order to give biomechanical support to the restoration. Anatomical and individual design of the pontic allows for proper healing of the soft tissue and good oral hygiene.¹⁵ Our modification is indicated in order to make medium-term, interim, or even definitive restorations. However, it should be remembered that anterior guidance, occlusal force management, and the size of the pontic area should be considered. The appropriate and thoughtful use of microhybrid composite in the functional zone, microfilled composite in aesthetic zone, and a multidirectional fiber material helps to ensure predictable and aesthetic restorations.

CLOSING COMMENTS
As reported with this clinical case, the technique demonstrated to obtain an anatomically individualized design of the pontics is a simple and predictable therapy in cases of single-tooth loss. More clinical research, with long-term follow-up on cases completed using this technique, is necessary.

References

1. SBU Board of Directors and Scientific Advisory Committee. Prosthetic rehabilitation of partially dentate or edentulous patients: a systematic review [report No. 204]. Stockholm, Sweden: Swedish Council on Technology Assessment in Health Care (SBU); November 2010.
2. Murdoch-Kinch CA, McLean ME. Minimally invasive dentistry. J Am Dent Assoc. 2003;134:87-95.
3. van Wijlen P. A modified technique for direct, fibre-reinforced, resin-bonded bridges: clinical case reports. J Can Dent Assoc. 2000;66:367-371.
4. Antón-Radigales M. Puentes de fibra de vidrio de confección directa: diez años después. RCOE. 2001;6:197-208. 
5. Hornbrook DS. Placement protocol for an anterior fiber-reinforced composite restoration. Pract Periodontics Aesthet Dent. 1997;9(suppl 5):1-5.
6. Shuman IE. Replacement of a tooth with a fiber-reinforced direct bonded restoration. Gen Dent. 2000;48:314-318.
7. Strassler HE. Planning with diagnostic casts for success with direct composite resin bonding. J Esthet Dent. 1995;7:32-40.
8. van Heumen CC, Kreulen CM, Creugers NH. Clinical studies of fiber-reinforced resin-bonded fixed partial dentures: a systematic review. Eur J Oral Sci. 2009;117:1-6.
9. Husein A, Berekally T. Indirect resin-bonded fibre-reinforced composite anterior bridge: a case report. Aust Dent J. 2005;50:114-118.
10. Jordan RE, Suzuki M, Sills PS, et al. Temporary fixed partial dentures fabricated by means of the acid-etch resin technique: a report of 86 cases followed for up to three years. J Am Dent Assoc. 1978;96:994-1001.
11. Komine F, Tomic M. A single-retainer zirconium dioxide ceramic resin-bonded fixed partial denture for single tooth replacement: a clinical report. J Oral Sci. 2005;47:139-142.
12. Barwacz CA, Hernandez M, Husemann RH. Minimally invasive preparation and design of a cantilevered, all-ceramic, resin-bonded, fixed partial denture in the esthetic zone: a case report and descriptive review. J Esthet Restor Dent. 2014;26:314-323.
13. Sasse M, Kern M. All-ceramic resin-bonded fixed dental prostheses: treatment planning, clinical procedures, and outcome. Quintessence Int. 2014;45:291-297.
14. Stas Y. Cantilevered restorations using CAD/CAM Cerec chairside technology: a case report. Int J Comput Dent. 2008;11:131-138.
15. Suo WC, Wang Q, Yu YC, et al. Application of the fiber-reinforced resin in transitional denture after implantation [in Chinese]. Shanghai Kou Qiang Yi Xue. 2013;22:330-333.

Dr. Cremades maintains a private practice focusing exclusively on adhesive aesthetic dentistry in Madrid-Roma, Spain. In Europe, he is a leading expert on adhesive direct techniques. He is a professor at Universidad Europea de Madrid. He can be reached via email at drjaviercremades@hotmail.com.

Dr. Giovane, a graduate of Universidad Europea de Madrid, with his postgraduate degree from Universidad Complutense de Madrid, has a private practice focusing exclusively on adhesive aesthetic dentistry and fixed prosthodontics in Madrid-Roma, Spain. He is a professional master in aesthetic dentistry. He can be reached via email at vincenzogiovane@icloud.com.

Dr. Abad-Coronel is a professor at Universidad de Cuenca in Ecuador as well as a collaborative assistant professor Universidad Complutense de Madrid, Spain. He is a specialist in oral rehabilitation, aesthetic dentistry, and TMDs. He can be reached at cabad02@ucm.es.

Disclosures: The authors report no disclosures.

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