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 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 , 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 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

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a , 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.

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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 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 sufficiently particularly well suited as an tioned as part of informed consent long to provide the surface area interim prosthesis for adolescent that the Carolina bridge does not needed for successful bonding. patients with congenitally missing possess the strength of a conven- lateral incisors. However, where tional prosthesis and therefore must In most cases, a minimum inciso- indicated, the Carolina bridge also be used with caution to prevent dis- gingival height of 5 mm is needed can be used as a restorative alterna- lodgment. However, properly done, along the proximal surface to ensure tive in cases for which a more per- this type of bonded all-porcelain adequate bonding. To achieve this manent fixed prosthesis is neither pontic can provide an excellent requisite condition it is sometimes practical nor affordable owing to interim esthetic alternative. necessary to expose more of the the patient’s age, medical condition, clinical through a surgical or economic status (Figures 3 and CONTRAINDICATIONS procedure. In 4). Additionally, patients with miss- Carolina bridges are not indicated adolescent patients, this type of pro- ing lateral incisors and in whom the for the replacement of posterior cedure is generally not undertaken

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A B C D

Figure 3. A, Elderly patient with a missing maxillary lateral incisor. B, Porcelain pontic viewed on a model with a polyvinyl- siloxane index. C, Lingual view of a pontic on a model. D, All-porcelain bonded bridge viewed after placement. Note the long incisogingival length of connectors, which are essential to success.

until approximately age 15 years. A ADVANTAGES OF THE effectively protects the bond, often need for crown lengthening of abut- CAROLINA BRIDGE rendering a highly successful result. ment teeth is not uncommonly seen Carolina bridges offer many advan- in young patients who have recently tages over metal “winged” pontic- However, when used for replace- completed orthodontic treatment type bridges. Properly done, ment of missing anterior teeth, and whose teeth exhibit a buildup Maryland-type bridges (and adhe- Maryland-type bridges experience of redundant or hyperplastic tissue sion bridges) can serve as superb more problems owing to the limited along proximal surfaces. conservative prostheses for replace- amount of proximal surface area in ment of posterior missing teeth which to incorporate adequate Patients also must possess sound because, generally, sufficient surface retention features, such as proximal abutment teeth with small or no area is available for the incorpora- grooves. Certainly, success can be proximal restorations and with no tion of a number of retention fea- achieved with anterior Maryland crowns. Teeth with large Class III tures. These include occlusal rests, bridges in some cases, but the poten- or IV restorations are contraindi- inlay components, wrap-around tial for problems is much greater. cated as abutment teeth, as are retainer designs, and internally pre- teeth with crowns. Abutment teeth pared slots or grooves. In a well- The design of the Carolina bridge also must be sound periodontally, designed posterior Maryland avoids many of the problems asso- with little mobility. bridge, the design of the prosthesis ciated with Maryland bridges,

A B

Figure 4. A, Patient with a traumatically missing maxillary central incisor. B, An all-porcelain bonded bridge replaces the missing central incisor.

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including adhesion bridges. First, as By contrast, if one wing of a and sufficient crown length of the noted earlier, no definitive prepara- Maryland bridge becomes loose, abutment teeth exists. tion of the adjacent abutment teeth it is most difficult to remove the is required, making this approach bridge without damage to the pros- At the first appointment, shade totally reversible. Second, the all- thesis or the abutment tooth. Worse selection is determined, taking care porcelain Carolina bridge is highly yet, if the loose wing goes unde- that the teeth are not allowed to esthetic owing to the absence of a tected, caries can develop that dehydrate prior to this assessment. metal substructure. Esthetic vitality requires more extensive restoration An elastomeric impression is made from optimal light penetration is of the abutment tooth, often pre- of the anterior segment from which superb. By contrast, Maryland cluding re-treatment with a new a working cast is generated. An bridges are notoriously unesthetic Maryland bridge. In another worst- impression of the opposing arch is because of the graying potential case scenario, if food impaction made, as well as a bite registration. created by the metal wings, particu- occurs between the loose metal larly in translucent abutment teeth. retaining wing and the underlying An all-porcelain pontic is fabricated Moreover, the metal framework in tooth, the tooth can actually be of feldspathic porcelain by the labo- the pontic area of an anterior displaced facially, requiring ortho- ratory (Figure 5B). Feldspathic Maryland bridge often limits the dontic correction. All of these porcelain is preferred to other thickness of porcelain needed to problems are avoided with the all- ceramic materials because of the ease achieve excellent esthetic vitality. porcelain Carolina bridge. with which it can be effectively etched with hydrofluoric acid. A Also, all-porcelain pontics, such as CLINICAL TECHNIQUE modified ridge lap pontic tip design the Carolina bridge, often can be In the case used to illustrate this is used for the Carolina bridge. The used when tooth anatomy precludes technique, an adolescent patient, proximal surfaces of the pontic are or restricts the preparation and age 14 years, presented with a etched with hydrofluoric acid to placement of a Maryland-type missing maxillary right lateral afford a highly retentive surface for bridge. For example, long, pointed incisor (Figure 5A). The patient adhesive bonding.21,22 It is important canines with proximal surfaces lost the clinical crown owing to that all surfaces to be bonded and exhibiting little incisogingival trauma. It was determined by a included in the resin composite con- height often lack adequate surface team consisting of a periodontist, nector area are effectively etched. It area for the placement of retention an orthodontist, an endodontist, is recommended that the surfaces to grooves (see Figure 1E and F). Also, and a restorative dentist that a den- be etched extend the full length of anterior teeth that are notably thin tal implant ultimately will be the the proximal surfaces incisogingi- faciolingually often still can be best treatment once the patient vally and extend onto the lingual treated with an all-porcelain Car- reaches maturity. To best preserve surface of the pontic at least to the olina bridge in many cases in which the bony site for subsequent position of the lingual line angle to a Maryland bridge would be an implant placement, it was decided ensure sufficient surface area for esthetic failure. to orthodontically submerge the bonding. A positioning stent or index endodontically treated root. A is fabricated from polyvinylsiloxane Third, the proximal resin composite Carolina bridge was selected as to facilitate positioning and bonding retaining connectors of all-porcelain the best interim prosthesis. The of the Carolina bridge at the deliv- Carolina bridges are easily repaired. occlusal relationship is favorable, ery appointment (see Figure 5B).

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At the second appointment, the vious to acid-etching and increases embrasures are not defined but involved abutment teeth are first the surface area for bonding, rather are bulked to strengthen the cleaned with flour of pumice in a thereby improving the bond resin composite connector. The prophy cup administered at slow strength of the resin connector to resin composite in each interproxi- speed using a prophy angle hand- the enamel surfaces of the abutment mal connector area is cured with a piece. The teeth are then thoroughly teeth. The enamel of the proximal light source directed from both rinsed, and the area is isolated with surfaces is acid etched using a 30 to facial and lingual directions for a bilateral cotton rolls. A 2 × 2–inch 35% phosphoric acid etching gel minimum time of 20 seconds each gauze is placed across the patient’s for a minimum of 15 seconds (Fig- to ensure complete maximal poly- mouth to prevent swallowing or ure 5E). Once etched, the proximal merization (Figure 5J). Additional aspiration of the pontic during try- surfaces must be kept clean and dry resin composite is added and cured in and cementation. Care must be to ensure optimal bonding. in any areas deemed deficient in taken not to allow the teeth to dehy- contour. As noted earlier, the lin- drate prior to shade assessment. At this point, the pontic is ready for gual contour of each resin compos- bonding into the edentulous space. ite connector should be continuous The pontic is carefully trial posi- Adhesive resin is placed on the mesiodistally from the line angle of tioned to assess the accuracy of the etched surfaces of the abutment teeth each abutment tooth across to the shade and the adaptation of the and porcelain pontic and is cured respective line angles of the porce- pontic to the residual ridge (Figure for 20 seconds (Figure 5F and G). lain pontic to maximize the cross- 5C). Once the accuracy of the A small amount of resin composite sectional diameter of the connectors shade and fit has been verified is applied to the proximal surfaces and achieve optimal strength. intraorally, the pontic is readied for of the pontic (Figure 5H). A hybrid cementation. If any contamination resin composite is recommended for The final contours of the resin of the etched proximal surfaces of the strength of the connectors. To composite connectors are achieved the porcelain pontic occurs during prevent premature curing of the resin using appropriate finishing burs. A try-in, these surfaces should be composite connectors during posi- series of abrasive points and cups cleaned by applying phosphoric tioning, it is recommended that the are used to finish and polish the acid briefly (a few seconds), fol- operatory light be turned away resin composite connectors. The lowed by thorough rinsing and dry- slightly to avert direct illumination occlusion is checked and adjusted ing of the pontic. A silane coupling during the bonding sequence. to ensure that only minimal centric agent is placed on the etched proxi- or functional contact is present. mal surfaces of the porcelain pontic Using the polyvinylsiloxane index, to improve the bond strength. the pontic is positioned in the eden- The patient is instructed in proper tulous space. Excess resin compos- oral hygiene techniques, including Preparation of the abutment teeth ite is removed with a resin the correct use of a floss threader to consists simply of light roughening composite instrument or an access the underside of the pontic of the proximal surfaces with a explorer (Figure 5I). The facial (Figure 5K). The patient (and/or the coarse, flame-shaped diamond embrasures are defined, and the patient’s parents) is once again stone (Figure 5D). Roughening gingival embrasures are shaped to reminded to avoid biting hard foods removes the outer fluoride-rich ensure that they are open to allow or objects to prevent fracture of con- layer of enamel that is more imper- access for cleaning. The lingual nector areas. Also, as for all bonded

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bridges, it is an important part of This consent should be given in writ- REPAIR OF THE RESIN informed consent that the patient ing, with a signature of acknowledg- COMPOSITE CONNECTOR (and/or the patient’s parents) once ment obtained from the patient or Although infrequently, patients will more be informed of the possibility the patient’s parent if the patient is a occasionally present with a frac- of swallowing or aspiration of the minor. The completed Carolina tured resin composite connector. pontic if it were totally dislodged. bridge is seen in Figure 5L and M. Usually, a fracture of a resin com-

A B

C D

E F G

Figure 5. A, Patient with a traumatically missing maxillary central incisor. B, Porcelain pontic viewed on a model with a polyvinylsiloxane index. C, Pontic being tried in place prior to bond- ing. Note protective gauze in place. D, Light roughening of the enamel proximal surfaces of the abutment teeth with a coarse diamond. E, Acid-etching of the involved proximal surfaces with phosphoric acid. F and G, A light-cured resin bonding agent is applied to both the proximal sur- faces of the abutment teeth and the pontic and cured prior to bonding of the pontic. (continued on next page)

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posite connector occurs when a diately aware if a resin composite biting a hard candy. The first step patient inadvertently bites on a connector fractures. in repair of the resin composite hard food or object. It is very rare connector is to use an ultrathin, that both connectors would frac- As seen in Figure 6, a patient pre- tapered diamond instrument to ture even from this type of insult. sented with a fractured resin com- remove the existing resin composite Almost always, patients are imme- posite connector that resulted from from the abutment tooth and the

H I

J K

L M

Figure 5 (continued). H, Resin composite is applied to the proximal surfaces of the pontic in preparation for bonding. I and J, The porcelain pontic is positioned using a PVS index, and the resin composite connectors are shaped and light-cured. K, The patient is instructed regarding the proper use of a floss threader to facilitate regular cleaning of the area. L and M, Lingual and facial views of the completed all-porcelain bonded pontic.

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porcelain pontic (see Figure 6A). If to protect the enamel surfaces of the Mylar strip, a silane coupling agent needed for adequate access, always abutment tooth during etching pro- can be applied and dried according open the connector at the expense cedures of the porcelain pontic. The to the manufacturer’s instructions. of the porcelain pontic. Never proximal surfaces of the porcelain remove tooth structure to gain pontic are etched using a 9.6% Following etching of the porcelain access for repair of the resin com- buffered hydrofluoric acid gel surfaces, the enamel surfaces of the posite connector. The remnants of applied for 2 minutes or as recom- abutment tooth are acid etched the resin composite connector must mended by the manufacturer. Care with a 30 to 35% phosphoric acid be removed to expose porcelain on must be taken to extend application etching gel for a minimum of the pontic and enamel on the abut- of the etching gel just beyond the 15 seconds. Thereafter, the enamel ment tooth to allow proper etching lingual line angle of the pontic to surfaces are rinsed for 5 to 10 sec- and bonding. achieve sufficient surface area for onds with a steady stream of water, bonding of the resin composite con- followed by air drying. Adhesive Once the connector area is free of nector. Following the timed applica- resin is placed on the etched sur- resin composite remnants and the tion of the porcelain etchant, the faces of the porcelain pontic and interproximal area is open, a rubber surfaces are thoroughly rinsed with the abutment tooth and is cured for dam is placed using the open con- water for 5 to 10 seconds. The 20 seconds. An appropriate shade tact for access (see Figure 6B). To etched porcelain surfaces are thor- of resin composite is inserted into ensure an optimal gingival seal dur- oughly dried. A lightly frosted the connector area and shaped ing etching and bonding, the rubber appearance should be evident. using an explorer or resin compos- dam is ligated. A Mylar strip is con- While maintaining isolation of the ite instrument, as noted previously toured and placed interproximally natural tooth abutment with a (see Figure 6C).

A B C

Figure 6. A and B, A fractured resin composite connector is removed with an ultra- slim, flame-shaped diamond instrument, exposing enamel and porcelain proximal surfaces. C, After proper etching of proximal surfaces (porcelain with 9.6% buffered hydrofluoric acid and enamel with 35% phosphoric acid), a new resin composite connector is generated. D, Immediate postoperative view of a repaired all-porcelain bonded bridge. Note the dehydration line consistent with the isolation level of the rubber dam.

D

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The final contours of the resin com- 4. Livaditis G, Thompson VP. Etched cast- ings: an improved retentive mechanism for posite connectors are achieved resin-bonded retainers. J Prosthet Dent using suitable finishing burs. A 1982;47:52. series of abrasive points and cups 5. Hansson O. The silicoater technique for are used to finish and polish the resin-bonded prostheses: clinical and labo- ratory procedures. Quintessence Int resin composite connectors. The 1989;20:85–99. occlusion should be assessed to 6. Matsumura H, Nakabayashi N. Adhesive ensure that no heavy centric or 4-META/MMA-TBB opaque resin with poly (methyl methacrylate)-coated tita- functional contact exists on the nium dioxide. J Dent Res 1988;67:29–32. newly placed resin composite con- 7. Ibsen RL, Strassler HE. An innovative nector. Again, the patient should be Figure 7. Typical all-porcelain bonded method for fixed anterior tooth replace- reminded to avoid biting hard bridge replacing a maxillary right cen- ment utilizing porcelain veneers. Quintes- tral incisor seen after 4 years, 2 months sence Int 1986;17:455–9. foods or objects. The final result of service. Stained areas of the resin can be seen in Figure 6D. composite connector typically require 8. Schaffer JL. All-porcelain anterior fixed resurfacing or replacement. partial denture: a preliminary report. J Prosthet Dent 1988;59:669–71.

Resin composite connectors will 9. Denissen HW, Gardner FB, Wijnhoff GF, periodically need surfacing, replace- et al. All porcelain anterior veneer bridges. J Esthet Dent 1990;2:22–7. ment, or repair owing to staining, cess is the availability of adequate wear, or fracture (Figure 7). How- surface area for bonding. 10. Moore DL, Demke R, Eick JD, Sigler TJ. Retentive strength of anterior etched ever, unlike other types of bonded porcelain bridges attached with resin com- bridges that are inherently invasive, DISCLOSURE AND posite resin: an in vitro comparison of ACKNOWLEDGMENT attachment techniques. Quintessence Int Carolina bridges use simple com- 1989;20:629–36. posite connectors that can be easily The author does not have any finan- 11. Denissen HW, Wijnhoff GF, Veldhuis AA, repaired. Additional strengthening cial interest in the companies whose Kalk W. Five-year study of all porcelain materials are discussed in this article. veneer fixed partial . J Prosthet of connector areas can be achieved Dent 1993;69:464–8. through the use of a fiber reinforc- The author wishes to acknowledge 12. Hornbrook DS. Anterior tooth replace- ing material, such as Ribbond ment using a two-component resin-bonded THM (Ribbond, Inc., Seattle, WA, the outstanding work of Mr. Daniel bridge. Compend Contin Educ Dent 1993;14:52–9. USA), if the occlusion allows. How- Materdomini of da Vinci Dental ever, additional reinforcement of Studios and Mr. Andre Theberge of 13. Leal FR, Cobb DS, Denehy GE, Margeas RC. A conservative aesthetic solution for this type is rarely needed if proper Drake Precision Dental Lab for a single anterior edentulous space: case case selection has occurred and suf- their technical expertise in the fab- report and one-year follow-up. Pract Proced Aesthet Dent 2001;13:635–41. ficiently large connectors have been rication of these prostheses. 14. Kern M, Knode H, Strubb JR. The all- achieved for optimal strength. porcelain, resin-bonded bridge. Quintes- REFERENCES sence Int 1991;22:257–62. 1. Rochette AL. Attachment of a splint to SUMMARY enamel of lower anterior teeth. J Prosthet 15. Trushkowsky RD. Replacement of con- The Carolina bridge is a novel all- Dent 1973;30:418. genitally missing lateral incisors with ceramic resin-bonded fixed partial den- porcelain bonded prosthesis that 2. Heymann HO. Resin-retained bridges: the tures. J Prosthet Dent 1995;73:12–6. can serve as an outstanding interim porcelain-fused-to-metal winged pontic. Gen Dent 1984;32:203–8. 16. Pospiech P, Rammelsberg P, Unsold F. A prosthesis for the replacement of new design for all-ceramic resin-bonded 3. Livaditis G. Cast metal resin-bonded fixed partial dentures. Quintessence Int single anterior incisors. As noted retainers for posterior tooth. J Am Dent 1996;27:753–8. repeatedly, the absolute key to suc- Assoc 1980;101:926.

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17. Antonson DE. Immediate temporary 20. Heymann HO. Additional conservative 22. Stangel I, Nathanson D, Hsu CS. Shear bridge using an extracted tooth. Dent Surv esthetic procedures. In: Roberson TM, strength of the composite bond to etched 1980;56:22–5. editor. The art and science of operative porcelain. J Dent Res 1987;66:1460–5. dentistry. 4th ed. St. Louis: CV Mosby Co; 18. Heymann HO. Resin-retained bridges: the 2001. p. 592–649. natural tooth pontic. Gen Dent Reprint requests: Harald O. Heymann, 1983;31:479–82. 21. Calamia JR. Etched porcelain facial DDS, Med, Department of Operative Den- veneers: a new treatment modality based tistry, UNC School of Dentistry, 302 Brauer 19. Heymann HO. Resin-retained bridges: the on scientific and clinical evidence. N Y J Hall, Chapel Hill, NC, USA 27599-7450; acrylic denture tooth pontic. Gen Dent Dent 1983;53:255–9. e-mail: [email protected] 1984;32:113–7. ©2006 Blackwell Publishing, Inc.

COMMENTARY

THE CAROLINA BRIDGE: A NOVEL INTERIM ALL-PORCELAIN BONDED PROSTHESIS W. Dan Sneed, DMD, MAT, MHS*

Adhesives have certainly changed the way we practice dentistry. Macromechanical resistance and retentive features have historically been a hallmark of quality restorative dentistry. Even today, it is certainly wise to incorporate mechanical design along with adhesives. This article, however, presents a very viable alternative to the traditional grooves, pins, and slots to retain a single-tooth pontic.

The author begins with a thorough review of the pertinent literature. He describes the various methods of fabricating conservative, single-tooth, fixed partial dentures, and most of these require some significant preparation of the abut- ment teeth. The author is intimately aware of his options, as well as the advantages and disadvantages of each. With that understanding, he then proposes a truly adhesive bridge that is totally reversible. At first read, this approach may seem futile. Many dentists have tried “gluing” pontics between two abutment teeth only to see them quickly fail. The difference here is the dentist’s clear understanding of the indications for and the limitations of this technique. There is also an understanding of occlusion and material and adhesive dynamics.

For this procedure, the author selects only patients who meet a defined set of criteria, and those patients understand what to expect. Then feldspathic porcelain is used because it, unlike some other ceramics, can be etched with hydroflu- oric acid. The application of a silane then ensures that the adhesive interface is stronger than the cohesive strength of either the porcelain or the composite.1–3 The enamel is lightly abraded with a diamond to enhance an already tenacious enamel bond.4 A hybrid composite is selected because of its strength. The connector areas must be of a certain width and length, and again and again, the author makes informed judgments.

The true message of this article is not just another technique but a process of problem solving based on knowledge and judgment. If we all approached restorative dentistry this way, with an informed patient and a knowledgeable dentist, surprises would be few and far between and success would be routine.

REFERENCES 1. Guler AU, Yilmaz F, Ural C, Guler E. Evaluation of 24-hour shear bond strength of resin composite to porcelain according to surface treatment. Int J Prosthodont 2005;18:156–60. 2. Knight JS, Homes JR, Bradford H, Lawson C. Shear bond strength of composite bonded to porcelain using porcelain repair systems. Am J Dent 2003;16:252–4. 3. Barghi N. To silanate or not to silanate: making a clinical decision. Compend Contin Educ Dent 2000;21:659–62. 4. Schneider PM, Messer LB, Douglas WH. The effect of surface reduction in vitro on the bonding of composite resin to permanent human enamel. J Dent Res 1981;60:895–900.

*Professor and chair, Department of General Dentistry, MUSC College of Dental Medicine, Charleston, SC, USA

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