- Email: [email protected]
Comparison of bond strengths of polymethyl methacrylate and alpha cyanoacrylate
Comparison methacryla&
of bond strengths of polymethyl and alpha cyanoacrylate
Frank J. Wiebelt, D.D.S.,* Manville Russell J. Stratton, D.D.S., M.S.*** University of Oklahoma,
College of Dentistry,
G. Duncanson, Oklahoma
Jr., D.D.S., Ph.D.,+*
and
City, Okla.
0
ver 20 million people in the United States wear complete dentures, and many others wear removable partial dentures. Regardlessof the method of fabrication, mostof thesedentures have somecomponentmade of polymethyl methacrylate. Although this material has many attributes that make it virtually indispensableto the practice of dentistry, it is subject to frequent fracture. Because of carelessness,accident, or abuse, millions of denture patients and their dentists face the problem of repairing broken dentures each year.’ The need for a quick and reliable method of repairing denture base material is undeniable. The advent of alpha cyanoacrylate as a versatile bonding medium has raisedquestionsabout its possibleapplication in clinical dentistry and in denture repair in particular.“-4 The objectives of this study were to (1) develop a method to produce uniform specimensof polymethyl methacrylate processedunder the same conditions and having the samephysical and chemical properties as commercially made denture basesand (2) to investigate the use of alpha cyanoacrylate as a bonding agent for polymethyl methacrylate and evaluate its bond strength versus that of autopolymerizing polymethyl methacrylate.
MATERIAL
AND
uniform
holes
in
METHODS
Eighty similar polymethyl methacrylate cylinders were fabricated in uniform holes 12.7 mm in diameter and 19 mm in length prepared with a drill pressin a gypsum mold (Figs. 1 to 3). Commercially available polymethyl methacrylate (Lucitone, L. D. Caulk Co., Milford, Del.) was trial packed into the openingswith a hydraulic bench press. Hanau flasks containing the
* \4srnnt Prole~sor. Department of Removable Prosthodontics. **,\ssorinte Professor and Chairman, Department of Dental hlaterials. ***Associate Profescor. Department of Removable Prosthodontics.
002%3913,‘R2,‘060603
Fig. 1. Drill press used to create gypsum mold.
+ 03$00.30/O
i” 1982 The C. V. Mosby
Co.
Fig. 2. Close-up
showing
holes after drilling.
sampleswere then immersedin a hydrothermal processor (Hanau Curing Unit, Teledyne Hanau, Buffalo, N.Y.) and cured for 8 hours using standard laboratory procedures. After curing, the sampleswere d&asked and examined for uniformity and absenceof significant porosity. The flash was removed in preparation for bonding. Half the sample cylinders were bonded with alpha cyanoacrylate (Eastman 9 10 Adhesive, Eastman Chemical Products, Inc., Kingsport, Tenn.). A drop of
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
603
WEBELT,
DUNCANSON,
AND
STi?ATIY)N
Fig. 3. Processed methyl methacxylate specimens 12.7 mm in diameter and 19 mm in length.
Fig. 5. Arrangement Instron.
for three-point
bending test on
Fig. 4. Cylinders immersed in pressure pot during bonding with autopolymerizing methyl methacrylate. Fig. 6. Failure of specimen bonded with merizing methyl methacrylate. cyanoacrylate was placed on each end of two cylinders that were held firmly together for 60 seconds. The remaining samples were bonded with autopolymerizing polymethyl methacryfate (Cold-Dent, Modern Materials Mfg. Co., St. Louis, MO.). The surfaces were coated with the polymethyl methacrylate mixture and approximated. No mechanical retention was used for reasons of comparison and consistency.5 The samples were placed on end in a pressurized container and immersed in warm water at 38” C and 20 psi for 10 minutes (Fig. 4). The excess at the bond junction was removed with an acrylic resin bur. These methods were used to produce 20 bonded sample cylinders of each type. Ten samples from each group were immediately subjected to a three-point bending test using an Instron Universal testing instrument (Instron Engineering Corp., Canton, Mass.) (Fig. 5). The load was increased at a cross-head speed of 5 mm per minute until failure occurred (Fig. 6). The remaining 10 samples from each group were stored in a water bath at 37” C for 90 days. These samples were then subjected to the same three-point test as described previously.
604
autopoly
RESULTS Most of the specimens failed in the same manner, exhibiting a fracture between the bonding medium and the processedmethyl methacrylate cylinders. A few of the methyl methacrylate-bonded specimens showed fracture lines that continued into the processed cylinders. The data were coHected(Table I), and an analysisof variance was performed. Results of the analysis of variance indicated a statistically significant difference among the groups. A Duncan’s multiple range test6 (p < .OS) was used as a specific comparison test and establishedthe following difference. The methyl methacrylate and cyanoacrylate bonding agentswere significantly different from each other whether stored in water or tested immediateIy. Although the bond strength was lessin both groups after storagein water, the differences were not statistically significant. DISCUSSION The results clearly demonstrate that poiymethyl methacrylate is superior to alpha cyanoacrylate as a
JUNE
1982
VOLUME
47
NUMBER
6
BOND
STRENGTHS
Table I. Results
of bending
test No.
Bonding Methyl
agent
Mean
of
samples
load
at failure ---psi
Pounds
.-_.
SD (pounds)
methacrylate Group Group
1
Dry
3
Water
(90
days)
10 10
112 105
1866.67 1750
26.7 35.4
2 4
Dry Water
(90
days)
10 10
53 46
883.33 766.67
22.9 20.1
Cyanoacrylate Group Group __x-
banding agent for denture repair in spite of the fact that no undercuts or mechanical retention were used to bond the samples with polymethyl methacrylate. Although storing the specimens in the water bath at 37” C for 90 days did weaken both types of bonds slightly, the polymethyl methacrylate bond was still significantly superior. This weakening of the adhesive properties of alpha cyanoacrylates in water is in accord with previous findings.’ SUMMARY A method of fabricating similar methyl methacrylate cylinders was used to produce specimens to test the bond strength of alpha cyanoacrylate and autopolymerizing methyl methacrylate. Each group was tested immediately and after storage in 37” C water bath for 90 days. Statistical analysis supported the finding that the autopolymerizing methyl methacrylate produced a better bond even without undercuts or mechanical retention.
2.
Bhaskar, Application surgery.
S. N..
Frisch,
J., Margetis,
P. M..
of a new chemical adhesive Oral Surg !22:526, 1966.
3.
Fukui, H., Lacy, hardening films 1980.
4.
Brauer. acrylic 58:1900.
h. M., and Jendresen, on die stone. J
6. 7.
ments. Fukushi, treatment
of cavity
L..
1964, Holt, Fusayama, walls.
.J Denr
and
Pallinhaqer,
C.
of Res
Stanford,
York, and
C.
D. j.: Bonding escrrs ,J Deny
Self--curing resins for repairing dentures: Some physical prop erties. J Am Dent Assor 51:307, 1955. Hicks, C R.: Fundamental Concepts in the Design of ExperiY.,
Burns,
F.:
and oral
5.
Sew
W.,
Leonard,
hi. D.. Effectiveness of PRO~THET &NT 44:5?.
G. M., Jackson, J. A., and l‘crmini, resins to dentin with Z-cyanoacrylat~ 1979 J.
and
in periodontics
C:.:
Rinehart & Minston. T.: Effect o!’ cyanoarrylatc Rrs
59~627,
I’%0
REFERENCES 1.
Koutlrlka.
B. hl.,
Nelson,
J. F.,
and
Webb,
self-repair: Experimental SOTC tissue response mrrcial adhesives. ,J PROSIXET DENT 43:143,
THE
IOURNAL
OF PROSTHETIC
DENTISTRY
J. G.: to selected 1980.
Denture com-
605
of bond strengths of polymethyl and alpha cyanoacrylate
Frank J. Wiebelt, D.D.S.,* Manville Russell J. Stratton, D.D.S., M.S.*** University of Oklahoma,
College of Dentistry,
G. Duncanson, Oklahoma
Jr., D.D.S., Ph.D.,+*
and
City, Okla.
0
ver 20 million people in the United States wear complete dentures, and many others wear removable partial dentures. Regardlessof the method of fabrication, mostof thesedentures have somecomponentmade of polymethyl methacrylate. Although this material has many attributes that make it virtually indispensableto the practice of dentistry, it is subject to frequent fracture. Because of carelessness,accident, or abuse, millions of denture patients and their dentists face the problem of repairing broken dentures each year.’ The need for a quick and reliable method of repairing denture base material is undeniable. The advent of alpha cyanoacrylate as a versatile bonding medium has raisedquestionsabout its possibleapplication in clinical dentistry and in denture repair in particular.“-4 The objectives of this study were to (1) develop a method to produce uniform specimensof polymethyl methacrylate processedunder the same conditions and having the samephysical and chemical properties as commercially made denture basesand (2) to investigate the use of alpha cyanoacrylate as a bonding agent for polymethyl methacrylate and evaluate its bond strength versus that of autopolymerizing polymethyl methacrylate.
MATERIAL
AND
uniform
holes
in
METHODS
Eighty similar polymethyl methacrylate cylinders were fabricated in uniform holes 12.7 mm in diameter and 19 mm in length prepared with a drill pressin a gypsum mold (Figs. 1 to 3). Commercially available polymethyl methacrylate (Lucitone, L. D. Caulk Co., Milford, Del.) was trial packed into the openingswith a hydraulic bench press. Hanau flasks containing the
* \4srnnt Prole~sor. Department of Removable Prosthodontics. **,\ssorinte Professor and Chairman, Department of Dental hlaterials. ***Associate Profescor. Department of Removable Prosthodontics.
002%3913,‘R2,‘060603
Fig. 1. Drill press used to create gypsum mold.
+ 03$00.30/O
i” 1982 The C. V. Mosby
Co.
Fig. 2. Close-up
showing
holes after drilling.
sampleswere then immersedin a hydrothermal processor (Hanau Curing Unit, Teledyne Hanau, Buffalo, N.Y.) and cured for 8 hours using standard laboratory procedures. After curing, the sampleswere d&asked and examined for uniformity and absenceof significant porosity. The flash was removed in preparation for bonding. Half the sample cylinders were bonded with alpha cyanoacrylate (Eastman 9 10 Adhesive, Eastman Chemical Products, Inc., Kingsport, Tenn.). A drop of
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
603
WEBELT,
DUNCANSON,
AND
STi?ATIY)N
Fig. 3. Processed methyl methacxylate specimens 12.7 mm in diameter and 19 mm in length.
Fig. 5. Arrangement Instron.
for three-point
bending test on
Fig. 4. Cylinders immersed in pressure pot during bonding with autopolymerizing methyl methacrylate. Fig. 6. Failure of specimen bonded with merizing methyl methacrylate. cyanoacrylate was placed on each end of two cylinders that were held firmly together for 60 seconds. The remaining samples were bonded with autopolymerizing polymethyl methacryfate (Cold-Dent, Modern Materials Mfg. Co., St. Louis, MO.). The surfaces were coated with the polymethyl methacrylate mixture and approximated. No mechanical retention was used for reasons of comparison and consistency.5 The samples were placed on end in a pressurized container and immersed in warm water at 38” C and 20 psi for 10 minutes (Fig. 4). The excess at the bond junction was removed with an acrylic resin bur. These methods were used to produce 20 bonded sample cylinders of each type. Ten samples from each group were immediately subjected to a three-point bending test using an Instron Universal testing instrument (Instron Engineering Corp., Canton, Mass.) (Fig. 5). The load was increased at a cross-head speed of 5 mm per minute until failure occurred (Fig. 6). The remaining 10 samples from each group were stored in a water bath at 37” C for 90 days. These samples were then subjected to the same three-point test as described previously.
604
autopoly
RESULTS Most of the specimens failed in the same manner, exhibiting a fracture between the bonding medium and the processedmethyl methacrylate cylinders. A few of the methyl methacrylate-bonded specimens showed fracture lines that continued into the processed cylinders. The data were coHected(Table I), and an analysisof variance was performed. Results of the analysis of variance indicated a statistically significant difference among the groups. A Duncan’s multiple range test6 (p < .OS) was used as a specific comparison test and establishedthe following difference. The methyl methacrylate and cyanoacrylate bonding agentswere significantly different from each other whether stored in water or tested immediateIy. Although the bond strength was lessin both groups after storagein water, the differences were not statistically significant. DISCUSSION The results clearly demonstrate that poiymethyl methacrylate is superior to alpha cyanoacrylate as a
JUNE
1982
VOLUME
47
NUMBER
6
BOND
STRENGTHS
Table I. Results
of bending
test No.
Bonding Methyl
agent
Mean
of
samples
load
at failure ---psi
Pounds
.-_.
SD (pounds)
methacrylate Group Group
1
Dry
3
Water
(90
days)
10 10
112 105
1866.67 1750
26.7 35.4
2 4
Dry Water
(90
days)
10 10
53 46
883.33 766.67
22.9 20.1
Cyanoacrylate Group Group __x-
banding agent for denture repair in spite of the fact that no undercuts or mechanical retention were used to bond the samples with polymethyl methacrylate. Although storing the specimens in the water bath at 37” C for 90 days did weaken both types of bonds slightly, the polymethyl methacrylate bond was still significantly superior. This weakening of the adhesive properties of alpha cyanoacrylates in water is in accord with previous findings.’ SUMMARY A method of fabricating similar methyl methacrylate cylinders was used to produce specimens to test the bond strength of alpha cyanoacrylate and autopolymerizing methyl methacrylate. Each group was tested immediately and after storage in 37” C water bath for 90 days. Statistical analysis supported the finding that the autopolymerizing methyl methacrylate produced a better bond even without undercuts or mechanical retention.
2.
Bhaskar, Application surgery.
S. N..
Frisch,
J., Margetis,
P. M..
of a new chemical adhesive Oral Surg !22:526, 1966.
3.
Fukui, H., Lacy, hardening films 1980.
4.
Brauer. acrylic 58:1900.
h. M., and Jendresen, on die stone. J
6. 7.
ments. Fukushi, treatment
of cavity
L..
1964, Holt, Fusayama, walls.
.J Denr
and
Pallinhaqer,
C.
of Res
Stanford,
York, and
C.
D. j.: Bonding escrrs ,J Deny
Self--curing resins for repairing dentures: Some physical prop erties. J Am Dent Assor 51:307, 1955. Hicks, C R.: Fundamental Concepts in the Design of ExperiY.,
Burns,
F.:
and oral
5.
Sew
W.,
Leonard,
hi. D.. Effectiveness of PRO~THET &NT 44:5?.
G. M., Jackson, J. A., and l‘crmini, resins to dentin with Z-cyanoacrylat~ 1979 J.
and
in periodontics
C:.:
Rinehart & Minston. T.: Effect o!’ cyanoarrylatc Rrs
59~627,
I’%0
REFERENCES 1.
Koutlrlka.
B. hl.,
Nelson,
J. F.,
and
Webb,
self-repair: Experimental SOTC tissue response mrrcial adhesives. ,J PROSIXET DENT 43:143,
THE
IOURNAL
OF PROSTHETIC
DENTISTRY
J. G.: to selected 1980.
Denture com-
605