A resin-bonded bridge replaces a missing tooth with a pontic attached to one or two thin retainer wings that are bonded to the enamel of the adjacent teeth. Done well, it saves sound tooth structure and lasts for many years; done poorly, it debonds. This article explains which cases suit the technique, how material and retainer design affect survival, the principles of preparation for metal and zirconia frameworks, and a bonding protocol that holds.
What a resin-bonded bridge is, and where the names come from
Rochette described a perforated metal splint bonded to the enamel of mandibular anterior teeth in 1973; resin flowed through tapered holes and locked the framework like a rivet. Livaditis and Thompson at the University of Maryland improved retention with etched castings in 1982, which is why metal resin-bonded bridges are still widely called Maryland bridges. In the literature you will find the same restoration as RBB, RBFDP (resin-bonded fixed dental prosthesis) or RBFPD (resin-bonded fixed partial denture), and in German as Adhäsivbrücke.
Today two families dominate:
- Metal-ceramic resin-bonded bridges with a non-precious alloy framework, typically cobalt-chromium. Kern lists cobalt-chromium as the first choice and nickel-chromium as the second choice because of the high rate of nickel allergy.
- All-ceramic resin-bonded bridges, today mostly made of veneered zirconia, almost always with a single retainer. The details of that design are covered in the article on the zirconia Maryland bridge.
Indications and case selection
The resin-bonded bridge is first of all a tooth-preserving option for a single missing tooth, most often an incisor, when the adjacent teeth are sound or minimally restored. Typical patients are adolescents and young adults with congenitally missing lateral incisors or teeth lost through trauma, in whom implants are not yet an option, and adults who prefer a less invasive option than an implant or a conventional bridge.
Before you plan the bridge, check these points:
- Enamel. Bonding needs sufficient enamel quality and a bonding surface of about 30 mm² per retainer. Bonding to large exposed dentin areas is not indicated, because the bond to dentin is weaker and not durable (Kern 2018).
- Space. The gap should match the natural width of the missing tooth, and there must be room for the retainer wing between the abutment and the opposing teeth. In adolescents this often means coordinating the space with the orthodontist before the brackets come off.
- Overbite. With an overbite of up to 3 mm, the wing on a maxillary incisor can usually sit cervical to the occlusal contacts. With 4 to 5 mm, check whether there is still enough enamel below the contacts and room for a connector of 3 × 2 mm (Kern 2018).
- Adjacent teeth. If an abutment already needs a crown, a conventional bridge or an implant may be the more logical choice.
- Oral hygiene. The margins are supragingival, but they are still plaque retention sites; motivate the patient during pretreatment.
The best data come from the anterior region. In the systematic review by Thoma et al. (2017), survival was higher for anterior than for posterior bridges, and in a series of 211 two-unit cantilever bridges, posterior bridges were retained less well than anterior ones (Botelho et al. 2014). Posterior cantilever zirconia bridges are being studied: a prospective trial reported 88.1 % survival after three years, with retainers at least 0.8 mm thick, at least 200° wraparound with an occlusal bar and 3 × 3 mm connectors (Lam et al. 2024). Treat posterior resin-bonded bridges as a more demanding indication.
One retainer or two?
The classic Maryland bridge had two wings, one on each neighbour. Because the two abutments move independently, the bridge is subjected to stresses between the abutments. With metal frameworks this often leads to debonding of one wing; the other wing keeps the bridge in place, so the loss of retention often goes unnoticed and caries can develop under the loose wing. With early all-ceramic two-wing bridges, the same stresses fractured one connector instead (Kern 2018).
The evidence now clearly favours the single-retainer (cantilever) design in the anterior region:
| Study | Comparison | Result |
|---|---|---|
| Kern and Sasse 2011 | All-ceramic (In-Ceram), 2 vs 1 retainer | 10-year survival 73.9 % vs 94.4 % |
| Botelho et al. 2016 | Maxillary incisor, 3-unit fixed-fixed vs 2-unit cantilever, RCT | After a mean of about 18 years: all cantilevers survived, 50 % of fixed-fixed |
| Thoma et al. 2017 | Systematic review, 2,300 bridges | One retainer: higher survival, lower debonding |
| Chen et al. 2018 | Systematic review, all-ceramic | Cantilever: higher survival, lower debonding and fracture rates |
A single retainer has further practical advantages: no need to make the abutment surfaces parallel, a simpler laboratory procedure, an open contact that can be flossed, and the patient notices at once if the bridge comes loose (Kern 2018).
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See all coursesPreparation principles
All modern resin-bonded bridge preparations stay within enamel. The exact elements depend on the framework material.
Metal frameworks
Metal wings twist and bend slightly under load. They therefore need retention and stiffening grooves, which means the abutment surfaces have to be prepared parallel to one path of insertion (Kern 2018). The systematic review by Balasubramaniam (2017) lists factors associated with better survival: a retentive tooth preparation, preparation confined to enamel, supragingival margins, nickel-chromium or cobalt-chromium alloys and no contact on the pontic in lateral excursions.
Zirconia frameworks
Ceramic wings are rigid and do not bend, so peeling forces do not arise. Retention grooves and parallel surfaces are not needed; instead, a flat proximal box and a small lingual pinhole give the bridge a defined seat, combined with a light cervical chamfer and a light incisal shoulder (Kern 2018). Kern specifies a minimum wing thickness of 0.7 mm for zirconia and a connector of 3 × 2 mm (height × thickness). Step-by-step details follow in the dedicated zirconia article linked above.
Before you cut
Plan the case on articulated study casts. A diagnostic wax-up transferred as a mock-up shows the pontic and the space for the wing before the first tooth is touched. Mark centric and eccentric contacts with articulating paper and shimstock; existing contacts on the abutment are usually kept and left outside the wing (Kern 2018).
Bonding protocol
Resin-bonded bridges fail at the bond, so the bonding protocol matters as much as the design. The principle is the same for metal and zirconia: a clean, roughened and chemically active framework surface, properly etched enamel, a phosphate monomer (MDP) and no contamination.
- Isolate. Place a rubber dam before cleaning the enamel. Saliva or blood on etched enamel compromises the bond (Kern 2018).
- Clean the enamel with pumice or a prophylaxis powder.
- Air-abrade the framework. Kern uses 50 µm alumina at 2.5 bar (0.25 MPa) for cobalt-chromium (Kern 2018) and for zirconia (Kern and Gläser 2023), protecting any silicate veneering ceramic. Bond within minutes, because airborne contaminants inactivate the surface.
- Clean the framework. After air abrasion, Kern cleans metal frameworks ultrasonically in 99 % isopropanol for 3 minutes. For zirconia, avoid silicone fit checkers at try-in: saliva and silicone residues significantly reduce the bond, and air abrasion is the most effective way to remove them (Yang et al. 2007).
- Etch the enamel with 33-40 % phosphoric acid for about 30 seconds, rinse for at least 15 seconds and dry until the enamel looks frosty white. Self-etch adhesives alone do not bond well enough to enamel for this purpose (Kern 2018).
- Bond with an MDP-containing system. A durable bond to zirconia was achieved in vitro only after air abrasion combined with a phosphate-monomer resin (Kern and Wegner 1998). Some luting resins contain MDP; others need a separate metal or zirconia primer.
- Check the occlusion. Avoid contacts on the pontic in lateral excursions.
The general rules for bonding ceramics, including silane and try-in pastes, are covered in the veneer cementation protocol.
Survival and complications
| Source | Bridges | Survival |
|---|---|---|
| Thoma et al. 2017 | 2,300, all materials and designs | 91.4 % at 5 years, 82.9 % at 10 years |
| Botelho et al. 2014 | 211 two-unit cantilevers | 97 % at 5, 91 % at 10, 84 % at 15 years |
| Kern et al. 2025 | 310 anterior zirconia cantilevers | 97.3 % at 15 years |
Debonding is the most frequent complication. In the review by Thoma et al. it affected 15 % of bridges over 5 years, chipping of the veneering ceramic 4.1 %. In the review by Balasubramaniam, debonding accounted for 78 % of failures. A debonded single-retainer bridge can usually be rebonded: in the long-term zirconia cohort by Kern et al. (2025), 16 of 17 debonded bridges were rebonded without further complications.
Summary
A resin-bonded bridge is a reliable, tooth-preserving way to replace a single anterior tooth when enamel, space and occlusion allow it. One retainer outperforms two, zirconia and cobalt-chromium both bond durably after air abrasion and MDP, and enamel must be etched under isolation without contamination. For indications, preparation exercises and adhesive cementation with a live demonstration and hands-on sessions, see the in-person course on adhesive bridges with Prof. Daniel Edelhoff.
Frequently asked questions
How long does a resin-bonded bridge last?
In a systematic review of 2,300 resin-bonded bridges, estimated survival was 91.4 % after 5 years and 82.9 % after 10 years (Thoma et al. 2017). Single-retainer and zirconia bridges did better than the average. In a cohort of 310 anterior zirconia cantilever bridges, 15-year survival was 97.3 % (Kern et al. 2025). Debonding was the most common complication, and most debonded bridges can be rebonded.
What is the difference between a Maryland bridge and a resin-bonded bridge?
There is no clinical difference in principle. Maryland bridge is the traditional name for a metal resin-bonded bridge with etched castings, after the University of Maryland where Livaditis and Thompson developed the technique. Resin-bonded bridge, or resin-bonded fixed dental prosthesis, is the umbrella term and includes all-ceramic versions such as the single-retainer zirconia bridge.
How do you prepare teeth for a Maryland bridge?
The preparation stays in enamel. For metal wings, retention and stiffening grooves on parallel surfaces are needed; supragingival margins and preparation confined to enamel are associated with better survival. For zirconia single-retainer bridges, a light chamfer, a flat proximal box and a lingual pinhole replace the grooves. Plan for about 30 mm² of enamel bonding surface and a 3 × 2 mm connector.
Can a resin-bonded bridge replace a posterior tooth?
It can, but the evidence is weaker and survival lower than in the anterior region. Posterior bridges were retained less well in long-term cohorts, and a prospective trial on posterior zirconia cantilevers reported 88.1 % survival after three years. Such designs used thicker retainers with wraparound and an occlusal bar. Reserve posterior resin-bonded bridges for carefully selected cases.
Why does a resin-bonded bridge debond?
Common reasons are too little enamel or bonding to dentin, contamination of the etched enamel or the framework, missing air abrasion or a luting system without phosphate monomer, a retainer that is too thin, and stresses between two abutments. Occlusal contacts on the pontic in lateral excursions were also associated with poorer survival. Single-retainer designs debond less often than two-retainer designs.
