The Carolina Bridge: a Novel Interim All-Porcelain Bonded Prosthesis
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The Carolina Bridge: A Novel Interim All-Porcelain Bonded Prosthesis HARALD O. HEYMANN, DDS, MED * ABSTRACT Numerous bonded bridge designs have been advocated over the years for the temporary or per- manent replacement of missing teeth. Both metal and all-porcelain designs of bonded bridges have been advocated, with varying degrees of success. However, all of these designs involve some degree of tooth preparation, making them irreversible in nature. The Carolina bridge, a novel all- porcelain bonded pontic, requires no significant tooth preparation, making it an outstanding option as an interim prosthesis. The key to success is the availability of adequate surface area interproximally to ensure optimally strong resin composite connectors. CLINICAL SIGNIFICANCE This article describes the indications, contraindications, and clinical technique for the placement of an ultraconservative all-porcelain bonded bridge for the interim replacement of single incisors. (J Esthet Restor Dent 18:81–92, 2006) ith the advent of adhesive Etched metal surfaces afford strong type of bridge was the all-porcelain Wdentistry, many approaches micromechanical bonds of the veneer bridge.7–9 This design used have been advocated for the con- metal retaining wings to the adja- facial or lingual porcelain veneers servative replacement of missing cent abutment teeth. Soon there- bonded to adjacent abutment teeth anterior teeth. A myriad of bonded after, another version of the to retain a porcelain pontic. How- bridge designs have been intro- Maryland bridge, the adhesion ever, this type of bridge was found duced over the years. An early ver- bridge, was introduced and has to afford poor resistance to fracture sion of a bonded bridge was the been widely used.5,6 This design and unnecessarily covered other- Rochette-type bridge.1,2 This relies upon various surface treat- wise intact, healthy tooth structure design uses countersunk holes in ments (eg, sandblasting, silicoating) on abutment teeth.10,11 the metal retaining wings for reten- of the metal wings along with tion of the bridge to the lingual chemically adhesive cement formu- More recently, other tooth-colored surfaces of the adjacent teeth via a lations (eg, 4-META) to facilitate bonded bridges made from resin composite cement. strong resin-to-tooth bonds. processed resin or high-strength ceramics have been advocated. A Subsequently, Maryland bridges Additionally, tooth-colored versions variant of this type of processed were introduced that also incorpo- of the Maryland bridge have been resin bonded bridge, the Encore rated metal retaining wings.3,4 advocated. An early form of this bridge (da Vinci Dental Studios, *Professor, Department of Operative Dentistry, UNC School of Dentistry, Chapel Hill, NC, USA DOI 10.2310/6130.2006.00014 VOLUME 18, NUMBER 2, 2006 81 THE CAROLINA BRIDGE Woodland Hills, CA, USA), consists extracted natural tooth pontics, THE CAROLINA BRIDGE of a pontic used in conjunction and custom resin composite pon- The purpose of this article is to with a facially bonded porcelain tics.17–19 All of these bonded bridge review an alternative approach for veneer.12,13 Tooth-colored Mary- designs are exceptionally conserva- the replacement of single missing land bridges also have been noted tive and rely on resin composite incisors using a custom-fabricated in the literature made from In- connectors between the pontic and all-porcelain bonded pontic, the Ceram (Vita Zahnfabrik, Bad the abutment teeth for retention. Of Carolina bridge. This name was Säckingen, Germany).14–16 How- course, a favorable occlusion and coined by Drake Precision Dental ever, owing to the fact that sufficient surface area on the adja- Lab of Charlotte, NC, USA, in processed resin possesses little cent abutment teeth must be pre- the late 1990s. First used by the potential for chemical adhesion, sent to ensure optimal success with author in 1987, this simple design surface treatments, such as sand- these conservative bridge types. consists of a custom-made all- blasting, must be used to achieve Also, because these types of bonded porcelain pontic with an etched mechanical adhesion to abutment bridges do not provide the bond proximal surface that is bonded teeth. Similarly, mechanical adhe- strengths of conventional bridges to the adjacent abutment teeth sion is difficult to attain with In- and probably are not as strong as using resin composite connectors Ceram; however, silicoating does porcelain-fused-to-metal Maryland- (Figure 1).20 seem to improve adhesion with In- type bridges, they are typically Ceram to some degree. Regardless, advocated as interim or provi- The primary qualities of this type the incorporation of proximal sional restorations. of bonded bridge include ease of grooves is recommended to placement, esthetic vitality (no improve macromechanical retention Despite the more provisional nature metal substructure), ease of connec- of this bridge design.16 of these bridges, they have been tor repair, and a totally reversible widely used with success for the nature. As with all bonded bridges, All of these bridge types have been replacement of single missing the primary keys to success include used with varying degrees of suc- incisors in patients for whom a the availability of adequate surface cess, and when properly made, more permanent prosthesis is nei- area for bonding, favorable occlu- some can provide excellent bond ther practical nor affordable. This sion, and periodontally sound and strengths. However, all of these is particularly true for extracted stable abutment teeth. bridge designs share one significant natural tooth pontics. In many disadvantage: they all require some cases involving elderly patients with INDICATIONS degree of tooth preparation and, as compromised periodontal or med- Patients best suited for an all- such, are irreversible in nature. ical health or limited financial porcelain bonded Carolina bridge means, extracted natural tooth pon- are young adolescents with missing More conservative options for ante- tics afford a practical and beneficial maxillary incisors. Adolescent rior bonded bridges also have been alternative to more traditional pros- patients with congenitally missing introduced over the years that, by theses. Moreover, owing to the sim- maxillary lateral incisors are fre- contrast to the bridges noted above, plicity with which the resin quently ideal candidates (Figure 2). do not require any appreciable composite connectors can be tooth preparation. These include placed, these bridges are easy to Although the best long-term solu- bonded denture tooth bridges, repair and maintain. tion frequently is the placement of 82 JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY HEYMANN a dental implant, patient age often replacement in adolescent patients Both options are not very hygienic, precludes this option in adoles- has been a “flipper-type” tempo- with tissue inflammation and papil- cents. Heretofore the only rary prosthesis or a denture tooth lary hyperplasia being common reversible option for interim incisor attached to a Hawley retainer. resultant sequelae. A B C D E F Figure 1. A, Patient with congenitally missing maxillary lateral incisors. B, Bilateral, all- porcelain bonded bridges replace the missing lateral incisors. C and D, Right side, viewed before and after placement of a bonded bridge. E and F, Left side, viewed before and after placement of a bonded bridge. G, Lin- gual view of bilateral bonded bridges. Note that lingual embrasures are left undefined for G the strength of the connector. VOLUME 18, NUMBER 2, 2006 83 THE CAROLINA BRIDGE A B Figure 2. A, Patient with congenitally missing maxillary lateral incisors. B, Bilateral, all-porcelain bonded bridges replace the missing lateral incisors. In these cases, an all-porcelain remaining edentulous space is too teeth or canines because of the bonded pontic is an excellent small for an implant often are degree of occlusal stress encoun- interim prosthesis because of its excellent candidates for an all- tered in these areas. Additionally, totally reversible nature. Unlike porcelain bonded pontic of this patients exhibiting a deep-bite ante- Maryland-type bridges and other type. By slightly lapping the adja- rior occlusal relationship and/or bonded bridges involving some cent teeth, an esthetically accept- evidence of bruxism or clenching degree of tooth preparation, the all- able prosthesis can be obtained. involving the anticipated area to be porcelain bonded pontic, or Car- treated are contraindicated. olina bridge, requires no significant Ideally, patients should exhibit an tooth preparation, making it occlusal relationship with little ver- Most importantly, abutment teeth entirely reversible. The abutment tical overlap. Clearly, patients who must exhibit sufficient incisogingi- teeth can be returned to their origi- exhibit an end-to-end or slight val height to ensure adequate sur- nal virgin condition simply through open-bite anterior occlusal relation- face area for bonding. Short teeth removal of the bonded pontic and ship are well suited for this type of are contraindicated as abutments. the resin composite connectors. bridge. Adolescent, post–orthodon- The absolute key to success is the Subsequent treatment with an tic treatment patients often fall into availability of adequate surface area implant is not precluded. this ideal category. for bonding. This fact cannot be overemphasized. Accordingly, the As noted above, this alternative is In all cases, patients must be cau- abutment teeth must be