150
Australian Dental Journal, June, 1979 Volume 24, No. 3
The composite bridge Peter J. Cunningham, M.D.Sc. (Melb.), D.D.S. (Tor.), F.R.A.C.D.S.
ABSTRACT-The technique of using composite resin for the adhesive in bonding acrylic or natural tooth pontics as a form of fixed prosthesis is presented. (Received for publication October, 1978)
Introduction This new field is probably the most important advance in bridgework in the last three decades. Utilization of avulsed or extracted teeth as pontics by employing a composite in connection with the acid etch techniques was first reported by Ibsen' in 1973. Shortly thereafter Ibsenz and Portnoy3 reported independently on a non-operative technique for replacing one tooth partials using an acrylic tooth or natural crown as the pontic. The advantages of the composite bridge i. The main advantage of the composite bridge or adhesive prosthodontics is that it offers yet one more option to the dentist in the spectrum of patient care. ii. The appliances will fail before the force becomes so great that the periodontium is adversely affected. They are really the most self-limiting procedure the dentist may perform for a patient. Indications i. When the expected life of the abutment teeth is short (for example, periodontal involvement). Such teeth are not only better cosmetically than a removable partial, but the bridge provides for splinting and stabilization as well.
I
2
3
Ibsen, R. L. - Fixed prosthetics with a natural crown pontic using an adhesive composite. Case history. J. South Calif. State Dent. Assoc., 41 : 2, 100-102 (Feb.) 1973. Ibsen, R. L. -One-appointment technique using an adhesive composite. Dent. Surv., 49: 2, 3&32 (Feb.) 1973. Portnoy, L. L.-Constructing a composite pontic in a single visit. Dent. Surv., 49: 8, 20-23 passim, (Aug.) 1973.
ii. In young people, when a fixed prosthesis requiring tooth preparation may be postponed for several years until the tooth matures or the pulp recedes. iii. Some adult patients (including other dentists) are reluctant to have teeth that are free from caries or restorations drilled to accommodate a fixed bridge. iv. Elderly patients. v. Patients in poor health. vi. Socio-economically deprived patients. Contraindications i. Cantilever bridges would probably not succeed, since the occlusal forces in most cases would exceed the bond strength between the pontic and the supporting crown. ii. Large diastema. iii. Inadequate interproximal space. iv. Deep overbite. v. Short clinical crowns for abutments. vi. Excessively long spans, although Ibsen' has frequently bonded three or four pontics in the anterior region, but it is better if they are separated by at least one abutment tooth. vii. Posterior spans. However, Portnoy3 has inserted many posterior bridges but the pontics are attached by retentive procedures to supplement adhesion such as box form preparations and pins. In this situation, the forces of mastication are greater and applied to broader occlusal tables. Technique i. Patient's own tooth. The root of the extracted tooth is excised and the pulp chamber is filled with a composite resin. The tooth
151
Australian Dental Journal, June, 1979
Fig. 2. -Composite contact areas trimmed hack.
Fig. 1. -Preparation of acrylic pontic. One empty, one over-filled with composite resin.
Fig. 4.- Painting the freshened composite contact area with unfilled resin.
Fig. 3.-Ruhber dam in place. Note a Class 111 cavity preparation in one abutment. This was necessary for caries removal, but not for bridge retention.
is stored in a humid environment until the following day. It should be allowed to dry out on the surface for about one hour prior to the bonding appointment. ii. Using an acrylic tooth pontic: (a) Impressions are taken of the upper and lower arches. (b) Resin pontics are prepared in advance. The contour of the pontics must be designed to allow self cleansing, including adequate embrasures. There must be a minimum of tissue contact. A tunnel4 is cut through the resin tooth where the contact areas will be and composite is squirted through and allowed to set (Fig. 1). Then the resin is trimmed back and the prepared pontic or pontics put aside (Fig. 2). Widdop, F.-Personal
communication, 1977
(c) The rubber dam is applied, no local anaesthetic is necessary (Fig. 3) and the enamel is etched by a diluted aqueous solution of phosphoric acid. (d) The unfilled resin is painted on the contact areas of the resin teeth (Fig. 4). (These contact areas are of set composite resin and they are freshened up by discing prior to painting with the unfilled resin). The etched enamel contact areas of the present abutment teeth are also painted with unfilled resin at this time. (The ultraviolet light composite system can be used, of course, instead of the chemical catalyst composite system.) (e) Use a small quantity of wet composite (filled resin) to position the tooth (Fig. 5 ) ; it is moistened by adding a little more unfilled resin. (Jordan and his colleaguesS suggested preliminary luting of the pontics Jordan, R. E., Suzuki, M., Sills, P. S., Gratton, D. R.,and Gwinett, J. A. -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.A.D.A., 96: 6, 994-1001 (June) 1978.
152
Fig. 5 . -Lateral in position by way of initial wet composite mix.
to the abutments labial to the contact points with a cyanoacrylate clear resin which is later removed.) The pontic is simply held by thumb and forefinger until this initial mix has hardened. Stolpa6 described a positioning matrix of tinfoil lined Duralay which could be used to advantage. (0 After the positioning composite has hardened, additional composite may be applied lingually for reinforcement (Fig. 6) . (g) After 10-15 minutes, finish with conventional equipment, paying special attention to preserving a good embrasure. Discussion Lambert, Moore, and Elletson' studied the in vitro strength of fixed composite bridges. They found that the mean fracture load to displace an upper lateral pontic was 41 ' 5 Ib/sq in towards the incisal and 55.8 Ib/sq in towards the gingival. Howell and Manlys reported loads during mastication on upper cuspids, laterals, and centrals of 51 3-51'5, 38.0-38.5, and 36'5-38.2 Ibs/sq in. If, as Manly and Braley9 concluded, normal chewing only generates a tenth of the maximum force, fixed bridges constructed in this manner should function quite adequately when properly placed in suitable situations. Dislodgement of the resin pontic can occur following adhesive failure. This has happened on three occasions in my practice. The failure occurred between adhesive Stolpa, J. B.-An adhesive technique for small anterior fixed partial dentures. J. Prosthet. Dent., 34: 5, 513-519 (Nov.) 1975. ' Lambert, P. M., Moore, D. L., and Elletson, H. H.-In v i m retentive strength of fixed bridges constructed with acrylic pontics and an ultraviolet-light-polymerized resin. J.A.D.A., 92: 4, 74&743 (Apr.) 1976. Howell, A. H., and Manly, R. S. - Electronic strain gauge for measuring oral forces. J. Dent. Res., 27: 6, 705-712 (Dec.) 1948. Manly, R. S., and Braley, Louise C.-Masticatory performanceandefficiency. J. Dent. Res., 29: 4,448-462(Aug.) 1950.
Australian Dental Journal, June, 1979
Fig. 6.-Composite
added lingually to strengthen the contact areas.
and the pontic tooth. This was before the use of the composite core in the resin tooth was a d ~ o c a t e d . ~ If the failure is cohesive, that is a cohesive fracture within the bulk of the bonding resin, it is because of the obvious limitation or lack of strength of bonding resins relative to the functional demands of the oral environment. Lower anterior composite bridges, however, are successful since the forces of mastication are low in this situation and a permanent cast bridge is often difficult to construct. The longevity of composite bridges is clearly dependent on the following factors: (1) proper adjustment of the occlusion, particularly protrusive and lateral-protrusive; (2) co-operation of the patient, particularly relative to incisive function, soon after the restoration ; and (3) the presence of posterior occlusal support. Conclusion The useful life of these prostheses depends upon the frequency and degree of stress placed on the adhesive bond, the ability of the operator to achieve a strong bond, and the manner in which the adhesive material is able to withstand the moisture, thermal cycling, and deformation encountered. The adhesively bonded fixed pontics are readily constructed and do not usually involve any sacrifice of sound tooth structure, so that in the event of failure, conventional restorative techniques can be used without encountering any technical problem not originally present. Although adhesive prostheses are somewhat limited in application, where they are applied with currently available materials and current techniques they prove exceptionally valuable in selected patients. Indeed, they allow the dentist to practice in a more conservative manner than ever before in the history of dentistry. 81 Collins Street, Melbourne, Vic., 3000.
Australian Dental Journal, June, 1979 Volume 24, No. 3
The composite bridge Peter J. Cunningham, M.D.Sc. (Melb.), D.D.S. (Tor.), F.R.A.C.D.S.
ABSTRACT-The technique of using composite resin for the adhesive in bonding acrylic or natural tooth pontics as a form of fixed prosthesis is presented. (Received for publication October, 1978)
Introduction This new field is probably the most important advance in bridgework in the last three decades. Utilization of avulsed or extracted teeth as pontics by employing a composite in connection with the acid etch techniques was first reported by Ibsen' in 1973. Shortly thereafter Ibsenz and Portnoy3 reported independently on a non-operative technique for replacing one tooth partials using an acrylic tooth or natural crown as the pontic. The advantages of the composite bridge i. The main advantage of the composite bridge or adhesive prosthodontics is that it offers yet one more option to the dentist in the spectrum of patient care. ii. The appliances will fail before the force becomes so great that the periodontium is adversely affected. They are really the most self-limiting procedure the dentist may perform for a patient. Indications i. When the expected life of the abutment teeth is short (for example, periodontal involvement). Such teeth are not only better cosmetically than a removable partial, but the bridge provides for splinting and stabilization as well.
I
2
3
Ibsen, R. L. - Fixed prosthetics with a natural crown pontic using an adhesive composite. Case history. J. South Calif. State Dent. Assoc., 41 : 2, 100-102 (Feb.) 1973. Ibsen, R. L. -One-appointment technique using an adhesive composite. Dent. Surv., 49: 2, 3&32 (Feb.) 1973. Portnoy, L. L.-Constructing a composite pontic in a single visit. Dent. Surv., 49: 8, 20-23 passim, (Aug.) 1973.
ii. In young people, when a fixed prosthesis requiring tooth preparation may be postponed for several years until the tooth matures or the pulp recedes. iii. Some adult patients (including other dentists) are reluctant to have teeth that are free from caries or restorations drilled to accommodate a fixed bridge. iv. Elderly patients. v. Patients in poor health. vi. Socio-economically deprived patients. Contraindications i. Cantilever bridges would probably not succeed, since the occlusal forces in most cases would exceed the bond strength between the pontic and the supporting crown. ii. Large diastema. iii. Inadequate interproximal space. iv. Deep overbite. v. Short clinical crowns for abutments. vi. Excessively long spans, although Ibsen' has frequently bonded three or four pontics in the anterior region, but it is better if they are separated by at least one abutment tooth. vii. Posterior spans. However, Portnoy3 has inserted many posterior bridges but the pontics are attached by retentive procedures to supplement adhesion such as box form preparations and pins. In this situation, the forces of mastication are greater and applied to broader occlusal tables. Technique i. Patient's own tooth. The root of the extracted tooth is excised and the pulp chamber is filled with a composite resin. The tooth
151
Australian Dental Journal, June, 1979
Fig. 2. -Composite contact areas trimmed hack.
Fig. 1. -Preparation of acrylic pontic. One empty, one over-filled with composite resin.
Fig. 4.- Painting the freshened composite contact area with unfilled resin.
Fig. 3.-Ruhber dam in place. Note a Class 111 cavity preparation in one abutment. This was necessary for caries removal, but not for bridge retention.
is stored in a humid environment until the following day. It should be allowed to dry out on the surface for about one hour prior to the bonding appointment. ii. Using an acrylic tooth pontic: (a) Impressions are taken of the upper and lower arches. (b) Resin pontics are prepared in advance. The contour of the pontics must be designed to allow self cleansing, including adequate embrasures. There must be a minimum of tissue contact. A tunnel4 is cut through the resin tooth where the contact areas will be and composite is squirted through and allowed to set (Fig. 1). Then the resin is trimmed back and the prepared pontic or pontics put aside (Fig. 2). Widdop, F.-Personal
communication, 1977
(c) The rubber dam is applied, no local anaesthetic is necessary (Fig. 3) and the enamel is etched by a diluted aqueous solution of phosphoric acid. (d) The unfilled resin is painted on the contact areas of the resin teeth (Fig. 4). (These contact areas are of set composite resin and they are freshened up by discing prior to painting with the unfilled resin). The etched enamel contact areas of the present abutment teeth are also painted with unfilled resin at this time. (The ultraviolet light composite system can be used, of course, instead of the chemical catalyst composite system.) (e) Use a small quantity of wet composite (filled resin) to position the tooth (Fig. 5 ) ; it is moistened by adding a little more unfilled resin. (Jordan and his colleaguesS suggested preliminary luting of the pontics Jordan, R. E., Suzuki, M., Sills, P. S., Gratton, D. R.,and Gwinett, J. A. -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.A.D.A., 96: 6, 994-1001 (June) 1978.
152
Fig. 5 . -Lateral in position by way of initial wet composite mix.
to the abutments labial to the contact points with a cyanoacrylate clear resin which is later removed.) The pontic is simply held by thumb and forefinger until this initial mix has hardened. Stolpa6 described a positioning matrix of tinfoil lined Duralay which could be used to advantage. (0 After the positioning composite has hardened, additional composite may be applied lingually for reinforcement (Fig. 6) . (g) After 10-15 minutes, finish with conventional equipment, paying special attention to preserving a good embrasure. Discussion Lambert, Moore, and Elletson' studied the in vitro strength of fixed composite bridges. They found that the mean fracture load to displace an upper lateral pontic was 41 ' 5 Ib/sq in towards the incisal and 55.8 Ib/sq in towards the gingival. Howell and Manlys reported loads during mastication on upper cuspids, laterals, and centrals of 51 3-51'5, 38.0-38.5, and 36'5-38.2 Ibs/sq in. If, as Manly and Braley9 concluded, normal chewing only generates a tenth of the maximum force, fixed bridges constructed in this manner should function quite adequately when properly placed in suitable situations. Dislodgement of the resin pontic can occur following adhesive failure. This has happened on three occasions in my practice. The failure occurred between adhesive Stolpa, J. B.-An adhesive technique for small anterior fixed partial dentures. J. Prosthet. Dent., 34: 5, 513-519 (Nov.) 1975. ' Lambert, P. M., Moore, D. L., and Elletson, H. H.-In v i m retentive strength of fixed bridges constructed with acrylic pontics and an ultraviolet-light-polymerized resin. J.A.D.A., 92: 4, 74&743 (Apr.) 1976. Howell, A. H., and Manly, R. S. - Electronic strain gauge for measuring oral forces. J. Dent. Res., 27: 6, 705-712 (Dec.) 1948. Manly, R. S., and Braley, Louise C.-Masticatory performanceandefficiency. J. Dent. Res., 29: 4,448-462(Aug.) 1950.
Australian Dental Journal, June, 1979
Fig. 6.-Composite
added lingually to strengthen the contact areas.
and the pontic tooth. This was before the use of the composite core in the resin tooth was a d ~ o c a t e d . ~ If the failure is cohesive, that is a cohesive fracture within the bulk of the bonding resin, it is because of the obvious limitation or lack of strength of bonding resins relative to the functional demands of the oral environment. Lower anterior composite bridges, however, are successful since the forces of mastication are low in this situation and a permanent cast bridge is often difficult to construct. The longevity of composite bridges is clearly dependent on the following factors: (1) proper adjustment of the occlusion, particularly protrusive and lateral-protrusive; (2) co-operation of the patient, particularly relative to incisive function, soon after the restoration ; and (3) the presence of posterior occlusal support. Conclusion The useful life of these prostheses depends upon the frequency and degree of stress placed on the adhesive bond, the ability of the operator to achieve a strong bond, and the manner in which the adhesive material is able to withstand the moisture, thermal cycling, and deformation encountered. The adhesively bonded fixed pontics are readily constructed and do not usually involve any sacrifice of sound tooth structure, so that in the event of failure, conventional restorative techniques can be used without encountering any technical problem not originally present. Although adhesive prostheses are somewhat limited in application, where they are applied with currently available materials and current techniques they prove exceptionally valuable in selected patients. Indeed, they allow the dentist to practice in a more conservative manner than ever before in the history of dentistry. 81 Collins Street, Melbourne, Vic., 3000.
