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Shear bond strength of composite resin porcelain repair materials bonded to metal and porcelain
POSTERIOR
COMPOSITE
RESIN
AND
AN
AMALGAM
19. Wilson NHF, Smith GA, Wilson MA. A clinical trial of a visible light cured posterior composite resin restorative material: three-year results. Quint Inter 1986;17:643-52. 20. Secos JC, Wilson NHF, Norman RD, Bassiouny MA, Wilder AD, Robonson PA. An improved method for the assessment of cavomarginal discoloration [Abstract]. J Dent Res 1986;65:827. 21. Norman RD, Wilson NHF. Three-year findings of a multiclinical trial for a posterior composite. J PROSTHET DENT 1988;59:577-83. 22. Council on Dental Materials, Instruments, and Equipment. Expansion of the acceptance program for dental materials, instruments, and equipment: composite resin materials for occlusal class I and class II restorations. J Am Dent Assoc 1981;102:349-50.
Contributing author G. P. Stewart, Ph.D., Associate Professor and Head, Section of Dental Materials, Department of Restorative Dentistry, Southern Illinois University, School of Dental Medicine, Alton, Ill.
Reprint requests to: DR. RICHARD D. NORMAN SCHOOL OF DENTAL MEDICINE SOUTHERN ILLINOIS UNIVERSITY ALTON, IL 62002
Shear bond strength of composite resin porcelain materials bonded to metal and porcelain David A. Beck, D.D.S.,* Charles Hugh B. Douglas, D.D.S., M.S.* Medical
College of Virginia,
Virginia
repair
E. Janus, D.D.S., M.S.,* and
Commonwealth
University
School of Dentistry, Richmond,
Va. Two composite resins, bonding agents, surface treatment agents, dental porcelains, and nickel-chromium porcelain bonding dental casting alloys were used to test shear bond strengths of composite resins bonded to metal and porcelain. Bond strengths to porcelain were greater thaa to metal and to oxidized metal were greater than to machined metal. Significant differences were found between types of porcelains and casting alloys. (J PROSTHET DENT 1990;64:629-33.)
S-mce the mid 195Os,porcelain-fused-to-metal
has become the most widely used full-coverage cast metal restoration. Because the technique involves fusion of a brittle material to a ductile one, fractures of the brittle material can occur. Although fractures of the dental porcelain do not necessarily mean failure of the restoration, they pose an esthetic and functional dilemma for the patient and dentist. The patient and dentist alike would realize several advantages if the fracture could be repaired instead of the restoration being remade. However, for the repair to withstand functional loads, the bond between the repair material and remaining restoration must be strong and durable. In 1977 O’Brien1 presented a classification of failures within the porcelain-fused-to-metal system. Several investigators have reported that silane solutions can significantly improve the bond strength of acrylic or composite resins to dental porcelain.2-12 Several studies
Supported in part by a grant from Den-Mat Corporation, Santa Maria, Calif. *AssociateProfessor,Department of Restorative Dentistry. 10/l/21922 THE
JOURNAL
OF PROSTHETIC
DENTISTRY
reported that silane improved the bond strengths but had unpredictable shelf life. 4*6 Many studies of bond strength have used high-fusing porcelain denture teeth for the porcelain substrate.4* 6pI3 Bond strengths between composite resins and cast metal-usually a noble alloy-have been reported by several authors.2* 3,14*l5 The use of thermocycling is variable in the literature. Most studies using thermocycling report that bond strengths are reduced by thermocycling.4* 5,8,l1 This study was designed to test the shear bond strength of composite resin to the metal substrate of porcelainfused-to-metal restorations and to compare it with the bond strength to the dental porcelain.
MATERIAL
AND METHODS
Box-nail shaped plastic casting patterns, 8 to 10 mm long with a 3 mm diameter shaft and a 6 mm diameter head, were produced from a stainless steel die and invested in a phosphate bonded investment (Hi-Temp, Whip Mix Corporation, Louisville, Ky). Castings were m.ade,according to manufacturer’s specifications, by use of a gas-oxygen torch (Perkeo, West Germany) with a multiorifice tip, of two non-noble nickel-chromium-beryllium dental casting 529
BECK,
JANUS,
AND
DOUGLAS
Fig. 1. Representative sample of metal casting with porcelain applied before machining to uniform diameter.
Fig. 2. Composite resin specimens applied to metal casting in pharmaceutical capsules partially filled with polyvinyl siloxane impression material.
alloys: Biobond II (Dentsply International, York, Pa.) and Rexillium III (Jeneric Gold Co., Wallingford, Conn.). Castings were finished on a high-speed lathe connected to dust suction, and suitable eye and inhalation protection were worn. Each test sample was composed of a casting with a 1.5 mm thick layer of the paired porcelain fused to it (Fig. l), to which composite resin cylinders were bonded. The casting alloys and porcelains were paired in the following manner: Biobond II alloy and Biobond porcelain (Dentsply International), and Rexillium III alloy and Vita VMK 68 porgelain (Vident, Baldwin Park, Calif.). Three bonding surfaces were tested. They were oxidized alloy (produced by following manufacturers’ regimen for producing an oxidized surface), machined alloy, and fired unglazed porcelain. Prior to testing, both the machined alloy and fired porcelain were machined with a green stone (Shofu Dental Corp., Menlo Park, Calif.). Two currently marketed composite resins were used to produce the test samples. One was a porcelain repair material Ultra-Bond with Cerinate Prime and Gold Link (Den-Mat Corp., Santa Maria, Calif.). The second material
530
Fig. 3. Cross-section line drawing of metal casting (~1, in holding jig with porcelain layer (p) and composite resin (c) with shear loading apparatus in place. Arrow (f) depicts direction in which force is applied.
was a conventional composite resin filling material, Profile (L. D. Caulk, Milford, Del.). The samples made of Profile composite resin were bonded with a material marketed for porcelain repair, Fusion (George Taub and Company, Jersey City, N.J.) and a universal bonding agent, Prisma Universal Bond (L. D. Caulk). Shear bond strengths were measured for the composite resins bonded to the three types of test sample surfaces. The composite resin portions of the samples were formed with the cylindrical shape of a size 4 gelatin pharmaceutical capsule, Elanco Qualicaps (Eli Lilly, Indianapolis, Ind.). The closed end of the capsule was partially filled with a polyvinyl siloxane impression material, Reflect (Kerr/ Sybron, Romulus, Mich.), to limit the height of the composite resin cylinder (Fig. 2). Ten samples of each composite material bonded to the test bonding surface of each substrate material were tested at three different time periods: 24 hours, 7 days, and 30 days. The study required 360 specimens for the combinations of two composite resin/bonding materials, two different substrate materials (metal/porcelain), three differ-
NOVEMBER
1990
VOLUME
64
NUMBER
5
COMPOSITE
RESIN
PORCELAIN
REPAIR
MATERIALS
2000 -7 w Machined metal u Oxidized metal Porcelain
h
24h
7d
30d
Time Fig.
4. Bar graph illustrates influence of time on bond strength.
Fusion/Profile
Gold Link/ Ultrabond Composite
Fig.
5. Bar graph illustrates influence of composite resin on bond strength.
ent surfaces (oxidized, machined alloy, and porcelain), with three time periods. All samples were stored in water at 37’ C from the time of fabrication until testing. The 7-day and 30-day specimens were thermal cycled from 14’ C to 60” C for 500 cycles. Thermal cycled specimens were stored in water at 37” C water until testing (usually 1 to 2 hours). Testing was completed on an Instron Universal testing machine (Instron Corp., Canton, Mass.) with a specially constructed jig at a crosshead speed of 0.5 cm/min (Fig. 3).
RESULTS The results of this study were compiled quantitatively and qualitatively. Shear bond strengths were calculated
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
from the surface area and the force required to cause failure. In general, the composite resin bond strengths to porcelain were high compared with the low bond strengths to metal. Qualitative analysis involved making an evaluation of the site of fracture. Statistical analysis of the data was done with a four-way analysis of variance. The analysis was conducted by use of four main effects and then analyzed for 2-, 3-, or I-way interactions (Figs. 4 through 6). All mean bond strengths of the composite resins to the oxidized or machined alloy were significantly lower than their bond strength to porcelain. Bond strengths to machined alloy were unrelated to the type of composite resin, bonding agent, or time. The forces required to cause fail-
531
BECK,
Biobond IUBiobond
JANUS,
AND
DOUGLAS
Rexillium III/ Vita VMK-68
Substrate Material Fig.
6. Bar graph illustrates influence of substrate material on bond strength.
Table I. Qualitative analysis of composite resin bond site failures Porcelain lday Class
7day
Oxidized metal 30day
lday
No.
%
No.
%
No.
%
No.
7 30 22 20 22
9 24 11 12 1 0 57
16 42 19 21 2
8 8 0 27 17 0 60
13 13
Total No. of
4 18 13 12 13 0 60
0 0 0 0 49 0 49
I II III IV V VI
30day
lday
7day
30day
---
failure
of
7day
Machined metal
45 28
%
100
No. 0 0 0 0 48 0 48
%
100
No. 0 0 0 0 49 0 49
%
100
No. 0 0 0 0 58 0 58
%
100
No. 0 0 0 0 47 0 47
%
No.
%
0 0 0 57 3 60
100
95 5
specimens
ure in specimens bonded to machined alloy were consistently lower than those bonded to oxidized alloy. Bond strengths to oxidized alloy were influenced by changes in the type of composite resin, type of alloy, and the elapsed time between bonding and testing. Profile composite resin bonded to oxidized alloy with Fusion bonding agent had mean bond strengths greater than that of Ultra Bond porcelain repair material bonded with Gold Link material. Bond strengths to oxidized Biobond II alloy were significantly higher than those to oxidized Rexillium III alloy, with greater bond strengths found in the 24-hour and 30day specimens than in the 7-day specimens. Bond strengths to porcelain also proved to be affected by the type of porcelain, the type of composite resin, and the elapsed time between preparation and testing. Profile composite resin and Fusion porcelain repair material had higher bond strengths than Ultra Bond and Cerinate prime
532
materials. The bond strengths of specimens made on BioBond II/Biobond materials were higher than those of Rexillium/Vita materials. Generally, bond strengths to porcelain were higher at 24 hours and 7 days than at 30 days. Qualitative evaluation of the fractures was made by use of light microscopy. The specimens were grouped into one of the following six classes: I. II. III. IV. V. VI.
Failure at the porcelain-to-metal interface exposing more than 70% of the bonded surface area Failure at the porcelain-to-metal interface exposing between 70% and 20% of the bonded surface area Failure at the porcelain-to-metal interface exposing less than 20% of the bonded surface area Porcelain cohesive failure with little or no alloy exposed Failure at the composite resin-test surface interface exposing more than 70% of the bonded surface area Failure at the composite resin-test surface interface exposing between 70% and 20% of the bonded surface area
NOVEMBER
1990
VOLUME
64
NUMBER
5
COMPOSITE
RESIN
PORCELAIN
REPAIR
MATERIALS
Qualitative evaluation of the fracture sites is summarized in Table I. Most of the samples bonded to dental porcelain failed either at the porcelain-alloy interface or entirely within the porcelain. The samples of composite resin bonded to alloy all failed at the composite resin-alloy interface. Only two samples exhibited composite resin cohesive failure leaving some material adherent to the alloy. These two had significant porosity in the alloy, but there was no correlation between these sites of failure and the failure load. Even though there is a statistically significant difference between the strength of the bond to the oxidized surface of the two different alloys, it did not correlate with the site of failure of the specimens.
REFERENCES
CONCLUSIONS 1. Bond strengths of composite resin materials to porcelain are significantly greater than those to either machined or oxidized alloy. 2. Bond strengths of Ultra-Bond/Cerinate Prime/Gold Link materials were not significantly different from Profile/Fusion Resin/Prisms Universal Bond materials. 3. Bond strengths varied significantly for different types of porcelain, and different types of alloys used as substitutes. 4. Thermal cycling and age of specimens had an unclear influence on bond strength. 5. Restorations failing within the body of the porcelain veneer would be better candidates for repair than failures that extended to the alloy surface.
Bound volumes
available
1. Craig RG, ed. Dental materials review. Ann Arbor: University of Michigan Press, 1977;123-35. 2. Eames WB, Rogers LB, Feller PR, Price WR. Bonding agents for repairing porcelain and gold: an evaluation. Oper Dent 19’77;2:118-24. 3. Eames WB, Rogers LB. Porcelain repairs: retention after one year. Oper Dent 1979;45:75-7. 4. Newburg R, Pameijer CH. Composite resins bonded to porcelain with silane solution. J Am Dent Assoc 1978;96:288-91. 5. Nowlin TP, Barghi N, Marling BK. Evaluation of the bonding of three porcelain repair systems. J PROSTHET DENT 1981;46:516-8. 6. Semmelman JO, Kulp PR. Silane bonding porcelain teeth to acrylic. J Am Dent Assoc 1968;76:69-73. I. Highton RM, Caputo AA. Effectiveness of porcelain repair systems. J PROSTHET DENT 1979;42:292-4. of bond 8. Pratt RC, Burgess JO, Schwartz RS, Smith JH. Evaluation strength of six porcelain repair systems. J PROSTHET DENT 1989;62: 11-3. 9. Lacy AM, LaLuz J, Watanbe LG, Dellinger M. Effect of porcelain surface treatment on the bond to composite. J PROSTHET DENT 1988;60:28891. AM, Schneider RL, Aquilino SA. Bond strengths of 10. Diaz-Arnold intraoral porcelain repair materials. J PROSTHET DENT 1989;61:305-9. AM, Aquilino SA. An evaluation of the bond strengths of 11. Diaz-Arnold four organosilane materials in response to thermal stress. J PROSTHET DENT 1989;62:257-64. bond strengths using four organosi12. Bailey dH. Porcelain-to-composite lane materials. J PROSTHET DENT 1989;61:174-7. 13. Jochen DG, Caputo AA. Composite resin repair of porcelain denture teeth. d PROSTHET DENT 1977;38;6:673-9. 14. Tjan AHL, Nemetz H, Tjan AH. Bond strength of composite to metal mediated by metal adhesive promoters. ,I P‘ROSTHET DENT 1987;57: 550.4. 15. Naegli DG, Duke ES, Schwartz R. Adhesive bonding of composites to a casting alloy. J PROSTHET DENT 1988;60:279-83. Reprmt requests to: DR. DAVID A. BECK SCHOOL OF DENTISTRY, Box 566 MEDICAL COLLEGE OF VIRGINIA RICHMOND, VA 23298.0001
to subscribers
Bound volumes of the JOURNAL,OFPROSTHETICDENTISTRYare available to subscribers (only) for the 1990 issues from the publisher at a cost of $44.00 ($56.00 international) for Vol. 63 (January-June) and Vol. 64 (July-December). Shipping charges are included. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 30 days after publication of the last issue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Volumes 61 and 62 are also available. Payment must accompany all orders. Contact Mosby-Year Book, Inc., Circulation Department, 11830 Westline Industrial Drive, St. Louis, MO 63146-3318, USA, phone (800) 325-4177, ext. 7351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNAL subscription.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
533
COMPOSITE
RESIN
AND
AN
AMALGAM
19. Wilson NHF, Smith GA, Wilson MA. A clinical trial of a visible light cured posterior composite resin restorative material: three-year results. Quint Inter 1986;17:643-52. 20. Secos JC, Wilson NHF, Norman RD, Bassiouny MA, Wilder AD, Robonson PA. An improved method for the assessment of cavomarginal discoloration [Abstract]. J Dent Res 1986;65:827. 21. Norman RD, Wilson NHF. Three-year findings of a multiclinical trial for a posterior composite. J PROSTHET DENT 1988;59:577-83. 22. Council on Dental Materials, Instruments, and Equipment. Expansion of the acceptance program for dental materials, instruments, and equipment: composite resin materials for occlusal class I and class II restorations. J Am Dent Assoc 1981;102:349-50.
Contributing author G. P. Stewart, Ph.D., Associate Professor and Head, Section of Dental Materials, Department of Restorative Dentistry, Southern Illinois University, School of Dental Medicine, Alton, Ill.
Reprint requests to: DR. RICHARD D. NORMAN SCHOOL OF DENTAL MEDICINE SOUTHERN ILLINOIS UNIVERSITY ALTON, IL 62002
Shear bond strength of composite resin porcelain materials bonded to metal and porcelain David A. Beck, D.D.S.,* Charles Hugh B. Douglas, D.D.S., M.S.* Medical
College of Virginia,
Virginia
repair
E. Janus, D.D.S., M.S.,* and
Commonwealth
University
School of Dentistry, Richmond,
Va. Two composite resins, bonding agents, surface treatment agents, dental porcelains, and nickel-chromium porcelain bonding dental casting alloys were used to test shear bond strengths of composite resins bonded to metal and porcelain. Bond strengths to porcelain were greater thaa to metal and to oxidized metal were greater than to machined metal. Significant differences were found between types of porcelains and casting alloys. (J PROSTHET DENT 1990;64:629-33.)
S-mce the mid 195Os,porcelain-fused-to-metal
has become the most widely used full-coverage cast metal restoration. Because the technique involves fusion of a brittle material to a ductile one, fractures of the brittle material can occur. Although fractures of the dental porcelain do not necessarily mean failure of the restoration, they pose an esthetic and functional dilemma for the patient and dentist. The patient and dentist alike would realize several advantages if the fracture could be repaired instead of the restoration being remade. However, for the repair to withstand functional loads, the bond between the repair material and remaining restoration must be strong and durable. In 1977 O’Brien1 presented a classification of failures within the porcelain-fused-to-metal system. Several investigators have reported that silane solutions can significantly improve the bond strength of acrylic or composite resins to dental porcelain.2-12 Several studies
Supported in part by a grant from Den-Mat Corporation, Santa Maria, Calif. *AssociateProfessor,Department of Restorative Dentistry. 10/l/21922 THE
JOURNAL
OF PROSTHETIC
DENTISTRY
reported that silane improved the bond strengths but had unpredictable shelf life. 4*6 Many studies of bond strength have used high-fusing porcelain denture teeth for the porcelain substrate.4* 6pI3 Bond strengths between composite resins and cast metal-usually a noble alloy-have been reported by several authors.2* 3,14*l5 The use of thermocycling is variable in the literature. Most studies using thermocycling report that bond strengths are reduced by thermocycling.4* 5,8,l1 This study was designed to test the shear bond strength of composite resin to the metal substrate of porcelainfused-to-metal restorations and to compare it with the bond strength to the dental porcelain.
MATERIAL
AND METHODS
Box-nail shaped plastic casting patterns, 8 to 10 mm long with a 3 mm diameter shaft and a 6 mm diameter head, were produced from a stainless steel die and invested in a phosphate bonded investment (Hi-Temp, Whip Mix Corporation, Louisville, Ky). Castings were m.ade,according to manufacturer’s specifications, by use of a gas-oxygen torch (Perkeo, West Germany) with a multiorifice tip, of two non-noble nickel-chromium-beryllium dental casting 529
BECK,
JANUS,
AND
DOUGLAS
Fig. 1. Representative sample of metal casting with porcelain applied before machining to uniform diameter.
Fig. 2. Composite resin specimens applied to metal casting in pharmaceutical capsules partially filled with polyvinyl siloxane impression material.
alloys: Biobond II (Dentsply International, York, Pa.) and Rexillium III (Jeneric Gold Co., Wallingford, Conn.). Castings were finished on a high-speed lathe connected to dust suction, and suitable eye and inhalation protection were worn. Each test sample was composed of a casting with a 1.5 mm thick layer of the paired porcelain fused to it (Fig. l), to which composite resin cylinders were bonded. The casting alloys and porcelains were paired in the following manner: Biobond II alloy and Biobond porcelain (Dentsply International), and Rexillium III alloy and Vita VMK 68 porgelain (Vident, Baldwin Park, Calif.). Three bonding surfaces were tested. They were oxidized alloy (produced by following manufacturers’ regimen for producing an oxidized surface), machined alloy, and fired unglazed porcelain. Prior to testing, both the machined alloy and fired porcelain were machined with a green stone (Shofu Dental Corp., Menlo Park, Calif.). Two currently marketed composite resins were used to produce the test samples. One was a porcelain repair material Ultra-Bond with Cerinate Prime and Gold Link (Den-Mat Corp., Santa Maria, Calif.). The second material
530
Fig. 3. Cross-section line drawing of metal casting (~1, in holding jig with porcelain layer (p) and composite resin (c) with shear loading apparatus in place. Arrow (f) depicts direction in which force is applied.
was a conventional composite resin filling material, Profile (L. D. Caulk, Milford, Del.). The samples made of Profile composite resin were bonded with a material marketed for porcelain repair, Fusion (George Taub and Company, Jersey City, N.J.) and a universal bonding agent, Prisma Universal Bond (L. D. Caulk). Shear bond strengths were measured for the composite resins bonded to the three types of test sample surfaces. The composite resin portions of the samples were formed with the cylindrical shape of a size 4 gelatin pharmaceutical capsule, Elanco Qualicaps (Eli Lilly, Indianapolis, Ind.). The closed end of the capsule was partially filled with a polyvinyl siloxane impression material, Reflect (Kerr/ Sybron, Romulus, Mich.), to limit the height of the composite resin cylinder (Fig. 2). Ten samples of each composite material bonded to the test bonding surface of each substrate material were tested at three different time periods: 24 hours, 7 days, and 30 days. The study required 360 specimens for the combinations of two composite resin/bonding materials, two different substrate materials (metal/porcelain), three differ-
NOVEMBER
1990
VOLUME
64
NUMBER
5
COMPOSITE
RESIN
PORCELAIN
REPAIR
MATERIALS
2000 -7 w Machined metal u Oxidized metal Porcelain
h
24h
7d
30d
Time Fig.
4. Bar graph illustrates influence of time on bond strength.
Fusion/Profile
Gold Link/ Ultrabond Composite
Fig.
5. Bar graph illustrates influence of composite resin on bond strength.
ent surfaces (oxidized, machined alloy, and porcelain), with three time periods. All samples were stored in water at 37’ C from the time of fabrication until testing. The 7-day and 30-day specimens were thermal cycled from 14’ C to 60” C for 500 cycles. Thermal cycled specimens were stored in water at 37” C water until testing (usually 1 to 2 hours). Testing was completed on an Instron Universal testing machine (Instron Corp., Canton, Mass.) with a specially constructed jig at a crosshead speed of 0.5 cm/min (Fig. 3).
RESULTS The results of this study were compiled quantitatively and qualitatively. Shear bond strengths were calculated
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
from the surface area and the force required to cause failure. In general, the composite resin bond strengths to porcelain were high compared with the low bond strengths to metal. Qualitative analysis involved making an evaluation of the site of fracture. Statistical analysis of the data was done with a four-way analysis of variance. The analysis was conducted by use of four main effects and then analyzed for 2-, 3-, or I-way interactions (Figs. 4 through 6). All mean bond strengths of the composite resins to the oxidized or machined alloy were significantly lower than their bond strength to porcelain. Bond strengths to machined alloy were unrelated to the type of composite resin, bonding agent, or time. The forces required to cause fail-
531
BECK,
Biobond IUBiobond
JANUS,
AND
DOUGLAS
Rexillium III/ Vita VMK-68
Substrate Material Fig.
6. Bar graph illustrates influence of substrate material on bond strength.
Table I. Qualitative analysis of composite resin bond site failures Porcelain lday Class
7day
Oxidized metal 30day
lday
No.
%
No.
%
No.
%
No.
7 30 22 20 22
9 24 11 12 1 0 57
16 42 19 21 2
8 8 0 27 17 0 60
13 13
Total No. of
4 18 13 12 13 0 60
0 0 0 0 49 0 49
I II III IV V VI
30day
lday
7day
30day
---
failure
of
7day
Machined metal
45 28
%
100
No. 0 0 0 0 48 0 48
%
100
No. 0 0 0 0 49 0 49
%
100
No. 0 0 0 0 58 0 58
%
100
No. 0 0 0 0 47 0 47
%
No.
%
0 0 0 57 3 60
100
95 5
specimens
ure in specimens bonded to machined alloy were consistently lower than those bonded to oxidized alloy. Bond strengths to oxidized alloy were influenced by changes in the type of composite resin, type of alloy, and the elapsed time between bonding and testing. Profile composite resin bonded to oxidized alloy with Fusion bonding agent had mean bond strengths greater than that of Ultra Bond porcelain repair material bonded with Gold Link material. Bond strengths to oxidized Biobond II alloy were significantly higher than those to oxidized Rexillium III alloy, with greater bond strengths found in the 24-hour and 30day specimens than in the 7-day specimens. Bond strengths to porcelain also proved to be affected by the type of porcelain, the type of composite resin, and the elapsed time between preparation and testing. Profile composite resin and Fusion porcelain repair material had higher bond strengths than Ultra Bond and Cerinate prime
532
materials. The bond strengths of specimens made on BioBond II/Biobond materials were higher than those of Rexillium/Vita materials. Generally, bond strengths to porcelain were higher at 24 hours and 7 days than at 30 days. Qualitative evaluation of the fractures was made by use of light microscopy. The specimens were grouped into one of the following six classes: I. II. III. IV. V. VI.
Failure at the porcelain-to-metal interface exposing more than 70% of the bonded surface area Failure at the porcelain-to-metal interface exposing between 70% and 20% of the bonded surface area Failure at the porcelain-to-metal interface exposing less than 20% of the bonded surface area Porcelain cohesive failure with little or no alloy exposed Failure at the composite resin-test surface interface exposing more than 70% of the bonded surface area Failure at the composite resin-test surface interface exposing between 70% and 20% of the bonded surface area
NOVEMBER
1990
VOLUME
64
NUMBER
5
COMPOSITE
RESIN
PORCELAIN
REPAIR
MATERIALS
Qualitative evaluation of the fracture sites is summarized in Table I. Most of the samples bonded to dental porcelain failed either at the porcelain-alloy interface or entirely within the porcelain. The samples of composite resin bonded to alloy all failed at the composite resin-alloy interface. Only two samples exhibited composite resin cohesive failure leaving some material adherent to the alloy. These two had significant porosity in the alloy, but there was no correlation between these sites of failure and the failure load. Even though there is a statistically significant difference between the strength of the bond to the oxidized surface of the two different alloys, it did not correlate with the site of failure of the specimens.
REFERENCES
CONCLUSIONS 1. Bond strengths of composite resin materials to porcelain are significantly greater than those to either machined or oxidized alloy. 2. Bond strengths of Ultra-Bond/Cerinate Prime/Gold Link materials were not significantly different from Profile/Fusion Resin/Prisms Universal Bond materials. 3. Bond strengths varied significantly for different types of porcelain, and different types of alloys used as substitutes. 4. Thermal cycling and age of specimens had an unclear influence on bond strength. 5. Restorations failing within the body of the porcelain veneer would be better candidates for repair than failures that extended to the alloy surface.
Bound volumes
available
1. Craig RG, ed. Dental materials review. Ann Arbor: University of Michigan Press, 1977;123-35. 2. Eames WB, Rogers LB, Feller PR, Price WR. Bonding agents for repairing porcelain and gold: an evaluation. Oper Dent 19’77;2:118-24. 3. Eames WB, Rogers LB. Porcelain repairs: retention after one year. Oper Dent 1979;45:75-7. 4. Newburg R, Pameijer CH. Composite resins bonded to porcelain with silane solution. J Am Dent Assoc 1978;96:288-91. 5. Nowlin TP, Barghi N, Marling BK. Evaluation of the bonding of three porcelain repair systems. J PROSTHET DENT 1981;46:516-8. 6. Semmelman JO, Kulp PR. Silane bonding porcelain teeth to acrylic. J Am Dent Assoc 1968;76:69-73. I. Highton RM, Caputo AA. Effectiveness of porcelain repair systems. J PROSTHET DENT 1979;42:292-4. of bond 8. Pratt RC, Burgess JO, Schwartz RS, Smith JH. Evaluation strength of six porcelain repair systems. J PROSTHET DENT 1989;62: 11-3. 9. Lacy AM, LaLuz J, Watanbe LG, Dellinger M. Effect of porcelain surface treatment on the bond to composite. J PROSTHET DENT 1988;60:28891. AM, Schneider RL, Aquilino SA. Bond strengths of 10. Diaz-Arnold intraoral porcelain repair materials. J PROSTHET DENT 1989;61:305-9. AM, Aquilino SA. An evaluation of the bond strengths of 11. Diaz-Arnold four organosilane materials in response to thermal stress. J PROSTHET DENT 1989;62:257-64. bond strengths using four organosi12. Bailey dH. Porcelain-to-composite lane materials. J PROSTHET DENT 1989;61:174-7. 13. Jochen DG, Caputo AA. Composite resin repair of porcelain denture teeth. d PROSTHET DENT 1977;38;6:673-9. 14. Tjan AHL, Nemetz H, Tjan AH. Bond strength of composite to metal mediated by metal adhesive promoters. ,I P‘ROSTHET DENT 1987;57: 550.4. 15. Naegli DG, Duke ES, Schwartz R. Adhesive bonding of composites to a casting alloy. J PROSTHET DENT 1988;60:279-83. Reprmt requests to: DR. DAVID A. BECK SCHOOL OF DENTISTRY, Box 566 MEDICAL COLLEGE OF VIRGINIA RICHMOND, VA 23298.0001
to subscribers
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