Effects of Adhesion Promoters Resin-enamel Retention
on
JOSEPH R. JEDRYCHOWSKI*, ANGELO A. CAPUTO**, and ROBERTA FOLIART*** *Associate Professor, Section of Pediatric Dentistry, University of California, Los Angeles 90024, **Professor and Chairman, Section of Biomaterials, University of California, Los Angeles 90024, ***School of Dentistry, University of California, Los Angeles 90024 The adhesive effects of three adhesion promoters were compared utilizing three different filled resins on acid-etched human permanent teeth. The results demonstrated a significantly greater resistance to dislodgement of resins by shear forces when an NPG-GMA type of adhesion promoter was utilized. Type of resin did not influence resin retention.
J Dent Res 58(4) :1371-1376, April 1979
Introduction. Modifications of enamel surfaces to improve receptivity for adhesion of dental restoratives have been described in the dental literature. Various treatments, such as acids, alkalis, enzymes, and sequestrants, have been utilized to clean the surfaces of preparations and remove a part of the organic or inorganic portion of the enamel. The most commonly employed enamel pretreatment is the application of a 37-50% solution of phosphoric acid with 7% zinc-oxide buffer. Recently, attention has been directed to adhesion promoters, or coupling agents. These multifunctional molecules adsorb onto and alter the enamel surface so that interaction with the restorative resin by a chemical or physical process is facilitated. Von Fraunhoferl described the characteristics of an ideal adhesion promoter as one that is adsorbed onto the enamel surface as a monomolecular layer that will prevent contamination of the solid by organic substances. The portion of the molecule that is Received for publication April 24, 1978. Accepted for publication June 19, 1978. Supported in part by MCH-927, HD-04612, and 59-P-45192/9. A preliminary report of this study was presented at the 56th General Session of the International Association for Dental Research at Washington, D.C.; J. Dent. Res. 57: Special Issue A:339, Abstract 1060, 1978.
not adsorbed should leave a surface film that can be more easily wetted by the restorative resin and form a hydrophobic film to avoid water accumulation which could prevent efficient wetting by an uncured liquid restorative. Various compounds have been suggested for use as adhesion promoters.2 4 Antonucci and Bowen5 reported a method for synthesis of a polyfunctional surface-active amine accelerator expected to promote adhesion by complexation with surface metal ions, utilization of several chelating groups per molecule, and by functioning as polymerization accelerators for dental resins. A synthesized vinyl-benzyl phosphonic acid has demonstrated a significant increase in resinenamel bond strengths when compared to specimens which were not pre-treated.6 This enhanced adhesion was attributed to bonding between calcium groups in the enamel surface and phosphonate groups in the synthesized adhesion promoter. The increased adhesion of resins to enamel with an NPG-GMA type of adhesion promoter is supported by Misra and Bowen.7 While other investigators have demonstrated increased resin to primary enamel adhesion when utilizing the butylacrylate-polycarboxyl adhesion promoter in an in vivo study,8 a clinical investigation reported no benefits from the utilization of the same adhesion promoter with sealants on primary tooth surfaces.9 Various types of silane adhesion promoting agents have increased adhesion of polyurethanes and experimental liners. 1 Currently three adhesion promoters are available to the practitioner. One adhesion promoter designed to have good wetting capabilities by most liquid resins is a butyl acrylate-acrylic acid copolymer with polycarboxylate groups which react with glycidyl 1371
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
1372
J Deti t Res April 1 9 79
JEDR YCHOWSKIETAL.
methacrylate+. The carboxylic acid groups promote adsorption and adhesion to cationic surfaces such as hydroxyapatite. This type of adhesion promoter has been demonstrated to increase resin retention to primary tooth enamel.8 Another adhesion promoter which has been demonstrated by Bowenl0 to enhance adhesion of resin and enamel with dentin is a solution of N-(hydroxy-3-methacryloxypropyl)-N-phenylglycine, or NPG-GMA++. This monomer is capable of chelating with the calcium ion on the etched surfaces of the tooth and is capable of copolymerizing with restorative resins. A third type of adhesion promoter, a silane described as 34methacryloxypropyl) trimethoxysilane+++, has been shown to react with surface water and the inorganic portions of dentin. Commercially it is available as a bonding agent for bonding acrylic to porcelain and metal. The purpose of this investigation was to compare the adhesive effects of three adhesion promoters utilizing three different restorative resins to human permanent enamel.
Materials and methods.
bedded in acrylic bases and prepared in the following manner: Surfaces were cleaned with a slowly-rotating prophylaxis cup and a non-fluoridated pumice slurry; the teeth were rinsed with distilled water, dried, and etched with 50% phosphoric acid with 7% zinc-oxide buffer, rinsed for one minute with distilled water, and dried for one minute with compressed oil-free air. A pressure-sensitive adhesive-backed paper was punched with three holes of .010 inch diameter which acted as a template for resin attachment. This template insured that each resin sample tested would have the same resin enamel surface contact area and also limited the resin sample to the enamel area which received a particular treatment. One of the three treatment areas on the tooth specimen was then randomly assigned to receive one of three adhesion promoters or control and one of the three resins. Figure 1 shows a typical treatment combination. The adhesion promoters were applied with a cotton pellet immediately before the assigned resin was mixed to manufacturer's specifications and applied to the treatment area. The resin was applied by tamping it into a 0.1 25 inch diameter plastic tube, placing the tube over the treatment area, and condensing the resin against the enamel surface with a wooden dowel which acted as a plunger. The samples were stored in 100% humidity for twenty-four hours at
Twelve variables were examined in a completely crossed 3 x 4 experimental design. They were the use of one of three commercially available coupling agents on a control area and the use of one of three 370C. The resin-enamel bond strengths were restorative resins on an acid-etched enamel then determined with the use of an Instron surface. The adhesion promoters were a universal testing machine at a cross head butylacrylate-polycarboxyl type, an NPG- speed of 0.05 inches per minute (Figure 2). GMA type, a silane type, or a control sur- An orthodontic wire loop was attached to face where no adhesion promoter was used. the fixed arm of the testing device, with The resins used were Cervident*, Simulate* * the free end placed around the resin or Vytol***. Ten specimens were examined to be tested. The loop was placed sample at the for each possible treatment combination, resin-enamel interface to insure that the test resulting in a total of 120 specimens. forces were parallel to the enamel surface Recently-extracted, human, caries-free and resulted in a pure shear force. Forces permanent mandibular incisors were em- required to dislodge the resin specimens were recorded. The results were compared an analysis of variance. utilizing +Simulate Adhesion Promoter, Kerr Sybron Corp., Romulus, Mich. ++Cervident Adhesion Promoter, Pennwalt S.S. White Corp., Philadelphia, PA +++Fusion, George Taub Products and Fusion Co., Inc., Jersey City, N.J. *Pennwalt S.S. White, Philadelphia, PA **Kerr Sybron Corp., Romulus, Mich. ***L. D. Caulk Co., Milford, Delaware
Results. The measured retentive strengths indicated adhesive failures between resin and enamel. Specimens were examined, and none had resin remaining, which would indicate
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
Vol 58 No 4
ADHESION EFFECTS OFADHESIONPROMOTERS
1373
Typical Treatment Combination
1 Minute H3P0Q Etch Fig. l.-Typical Treatment Combination.
Assembly For Shea r Testin9 Load Cell
-
Looped Wire 1 Mkvt Hi,PQ Etch
Fig. 2. -Assembly for Shear Testing. Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
1374
J Dent Res April 1979
JEDR YCHOWSKI ETAL.
Collective
Shear
Stren9ths
MII SILANE * UTYL ACRYLATE POLYCOXYL o CONTROL r NtG-M STMDARD ERROR OF MEAN
O A%
'a
CERVIDENT
SIMULATE
VYTOL
Fig. 3. -Collective Shear Strengths, Grouped by Resin Type.
cohesive failure within the resin. The results of the analysis of variance (Table 1) demonstrated a significant primer effect of the p < .01 probability level. There was no significant effect from the type of resin utilized or from the interaction of primer and resin as demonstrated in the interaction term. Figure 3 depicts mean shear strengths for each treatment combination, grouped by the three resins utilized. There were no reversal trends for each resin type and, although there were no significant differences between resin types, the Cervident resin displayed slightly higher values for each of the primer types and the control groups than the Simulate or Vytol resins. Figure 4 shows combined mean values for each type of adhesion promoter. Sheffe's method demonstrated that the NPG-GMA adhesion promoter was significantly different from the average of the silane, butylacrylate-polycarboxyl, and control groups at
the p < .01 significance level. As mentioned previously, the resin-adhesion promoter combinations were randomly assigned to incisal, middle, or gingival thirds of the test specimens. There was no statistically significant relation between location on the test specimen and resistance to shear strengths.
TABLE 1 ANOVA SUMMARY TABLE Source
DF
MS
F Value
Primer (P) Resin (R) PXR Error
3 2 6 88
2327461
4.20* 2.12 0.27
117304 152048 554489
*p < .01
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
Vol S8 No 4
ADHESION EFFECTS OF ADHESION PROMOTERS
Combined Shear Strengths 1816-
14c
12-
g
1375
face changes. No effect could be demonstrated between resins attached to incisal, middle, or gingival thirds. A method is still needed to examine resins attached to enamel which is prepared or fractured parallel to enamel rods.
10-
Conclusions.
a 8A
64-
20-
altiEt
Ulllll
Fig. 4.-Combined Shear Strengths, Demonstrating a Significant (p < .01) Difference Between the NPG-GMA Adhesion Promoter and all Other Treatment Combinations.
Discussion. The present study investigated only those adhesion promoters available commercially that could be easily used by the dental practitioner. The results demonstrated a significant adhesive effect only when the NPGGMA adhesion promoter was utilized. No differences were demonstrated between the butylacrylate-polycarboxyl type, the silane type, or control specimens which were not pretreated with an adhesion promoter. The three resins utilized in this study were filled resins, the Cervident resin being a liqcuid-powder type while the Simulate and Vytol resins are two-part paste systems. The liquid-powder system, due to its low viscosity and angle of contact, might be expected to affect retentive strengths; however, type of resin did not influence retention, so choice of a filled resin could be influenced by color stability, marginal integrity, working and finishing properties. Synthesis of an ideal adhesion promoter would enable the clinician to place restorations, sealants, veneers, etc., with greater confidence in adhesive properties. Mechanical preparation, such as beveling or scalloping, to increase the area for adhesion could be eliminated. The labial tooth surface subjected to adhesive bonding in this study certainly does not represent all possible enamel surfaces which the clinician must restore, seal, or veneer. Labial surfaces differ in enamel crystallite orientation as location on the sur-
The effects of three adhesion promoters on shear strengths of three filled resins were compared. All resins separated from enamel specimens without evidence of cohesive resin failure. Location of the resins on labial tooth surfaces did not affect shear strengths, so placement of resins at gingival, middle, or incisal locations did not influence retention. Of the three resins compared, none influenced resistance to shear strength. The NPGGMA type of adhesion promoter significantly increased resin retention; however, no differences could be demonstrated between the butylacrylate-polycarboxyl type, the silane type, or control resins which were not pretreated with an adhesion promoter. Further investigation is required to examine the effects of adhesion promoters on resindentin bonding and the effects of newlydeveloped adhesion promoters.
Acknowledgment. The authors wish to express their thanks to the Word Processing Center, Irene Petravicius of the Dental Illustration Dept., School of Dentistry, and P. Schroth, Computing Resources Group, UCLA, M.R.R.C. REFERENCES 1. BRAUER, G. M.: Adhesion and Adhesives, in VON FRAUNHOFER, J. A. (ed.): Scientific Aspects of Dental Materials, London: Butterworths, 1975, pp. 49-96. 2. KRAMER, I.; and LEE, K. W.: The Demonstration of Glycerophosphoric Acid Dimethacrylate in Dentine and Filling Material Following the Use of a Cavity Sealer. J. Dent Res. 39:1003, 1960. 3. DRIESSENS, F. C. M.; BRAUER, G. M.; and TERMINI, D. J.: Chelating Agents as Potential Adhesives for Dental Restorations. J. Dent. Res., Program and Abstracts of Papers, 47th General Meeting, International Association for Dental Research, Abstract #137, 1969. 4. LEE, H.: Adhesion Between Lining Tissue and Plastics 1. Adhesion of Epoxy and Poly-
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
1376
J Deti t Res April 1 9 79
JEDR YCHO WSKI ET A L.
urethane Resins to Dentin and Enamel. J. Biomed. Mater. Res. 3:349, 1969. 5. ANTONUCCI, J. M.; and BOWEN, R. L.: Adhesive Bonding of Various Materials to Hard Tooth Tissues: XIII. Synthesis of a Polyfunctional Surface-Active Amine Accelerator. J. Dent. Res. 56(8):937-942, 1977. 6. FARLEY, E. P.; JONES, R. L.; and ANBAR, M.: Improved Adhesion of Acrylic Restoration Materials to Dental Enamel by Precoating With Monomers Containing Phosphonate Groups. J. Dent. Res. 56(8):943-952, 1977. 7. MISRA, D.; and BOWEN, R.: Adsorption of NPG-GMA on Hydroxyapatite, J. Dent. Res. 55:Abstract # 327, 1976.
8. SMUTKA, S.; JEDRYCHOWSKI, J.; and CAPUTO, A. A.: An Evaluation of Primary Enamel Pretreatments and Their Effects on Resin Retention, J. Denit Res. 57(7-8):796799, 1978. 9. CHARBENEAU, G. T.; DENNISON, J. B.; RYGE, G.: A Filled Pit and Fissure Sealant: 18 Month Results. JADA . 95:299-306, 1977. 10. BOWEN, R. L.: Adhesive Bonding of Various Material to Hard Tooth Tissues. II. Bonding to Dentin Promoted by a Surface-Active Comonomer. J. Dent. Res. 44:895, 1965. 11. MILLER, R. G.: Simultaneous Statistical Inference, New York, McGraw-Hill, 1966, p. 57.
CONFERENCE ANNOUNCEMENT CONFERENCE TO BE HELD ON MODELING TECHNIQUES AND APPLICATIONS IN DENTISTRY A four-day national conference on modeling of the dental delivery system in the U.S. and utilization of modeling as a dental manpower planning tool will be convened on July 16-19, 1979 at Northwestern University. The conference is designed to create an opportunity for developers of dental models, actual and potential users of those models, and dental planners, economists, and researchers to become familiar with current and future dental modeling activities. The objectives of the conference will be accomplished through a series of presentations and discussions by experts within the following topic areas: 1) single equation models of the dental sector; 2) national dental forecasting and dental policy and analysis models; 3) applications of State and regional dental models for planning; and 4) dental practice simulation models. A variety of techniques, applications, and viewpoints will be represented. Participants will include representatives of Federal agencies, other health planners, methodologists, economists, dental researchers, and health policy makers. Researchers from various health disciplines are invited to attend. The conference is being sponsored by The Bureau of Health Manpower, Health Resources Administration. For further information, contact Resources for Health, Education, and Communications, Inc., 962 Wayne Avenue, Suite 701, Silver Spring, MD 20910.
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
on
JOSEPH R. JEDRYCHOWSKI*, ANGELO A. CAPUTO**, and ROBERTA FOLIART*** *Associate Professor, Section of Pediatric Dentistry, University of California, Los Angeles 90024, **Professor and Chairman, Section of Biomaterials, University of California, Los Angeles 90024, ***School of Dentistry, University of California, Los Angeles 90024 The adhesive effects of three adhesion promoters were compared utilizing three different filled resins on acid-etched human permanent teeth. The results demonstrated a significantly greater resistance to dislodgement of resins by shear forces when an NPG-GMA type of adhesion promoter was utilized. Type of resin did not influence resin retention.
J Dent Res 58(4) :1371-1376, April 1979
Introduction. Modifications of enamel surfaces to improve receptivity for adhesion of dental restoratives have been described in the dental literature. Various treatments, such as acids, alkalis, enzymes, and sequestrants, have been utilized to clean the surfaces of preparations and remove a part of the organic or inorganic portion of the enamel. The most commonly employed enamel pretreatment is the application of a 37-50% solution of phosphoric acid with 7% zinc-oxide buffer. Recently, attention has been directed to adhesion promoters, or coupling agents. These multifunctional molecules adsorb onto and alter the enamel surface so that interaction with the restorative resin by a chemical or physical process is facilitated. Von Fraunhoferl described the characteristics of an ideal adhesion promoter as one that is adsorbed onto the enamel surface as a monomolecular layer that will prevent contamination of the solid by organic substances. The portion of the molecule that is Received for publication April 24, 1978. Accepted for publication June 19, 1978. Supported in part by MCH-927, HD-04612, and 59-P-45192/9. A preliminary report of this study was presented at the 56th General Session of the International Association for Dental Research at Washington, D.C.; J. Dent. Res. 57: Special Issue A:339, Abstract 1060, 1978.
not adsorbed should leave a surface film that can be more easily wetted by the restorative resin and form a hydrophobic film to avoid water accumulation which could prevent efficient wetting by an uncured liquid restorative. Various compounds have been suggested for use as adhesion promoters.2 4 Antonucci and Bowen5 reported a method for synthesis of a polyfunctional surface-active amine accelerator expected to promote adhesion by complexation with surface metal ions, utilization of several chelating groups per molecule, and by functioning as polymerization accelerators for dental resins. A synthesized vinyl-benzyl phosphonic acid has demonstrated a significant increase in resinenamel bond strengths when compared to specimens which were not pre-treated.6 This enhanced adhesion was attributed to bonding between calcium groups in the enamel surface and phosphonate groups in the synthesized adhesion promoter. The increased adhesion of resins to enamel with an NPG-GMA type of adhesion promoter is supported by Misra and Bowen.7 While other investigators have demonstrated increased resin to primary enamel adhesion when utilizing the butylacrylate-polycarboxyl adhesion promoter in an in vivo study,8 a clinical investigation reported no benefits from the utilization of the same adhesion promoter with sealants on primary tooth surfaces.9 Various types of silane adhesion promoting agents have increased adhesion of polyurethanes and experimental liners. 1 Currently three adhesion promoters are available to the practitioner. One adhesion promoter designed to have good wetting capabilities by most liquid resins is a butyl acrylate-acrylic acid copolymer with polycarboxylate groups which react with glycidyl 1371
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
1372
J Deti t Res April 1 9 79
JEDR YCHOWSKIETAL.
methacrylate+. The carboxylic acid groups promote adsorption and adhesion to cationic surfaces such as hydroxyapatite. This type of adhesion promoter has been demonstrated to increase resin retention to primary tooth enamel.8 Another adhesion promoter which has been demonstrated by Bowenl0 to enhance adhesion of resin and enamel with dentin is a solution of N-(hydroxy-3-methacryloxypropyl)-N-phenylglycine, or NPG-GMA++. This monomer is capable of chelating with the calcium ion on the etched surfaces of the tooth and is capable of copolymerizing with restorative resins. A third type of adhesion promoter, a silane described as 34methacryloxypropyl) trimethoxysilane+++, has been shown to react with surface water and the inorganic portions of dentin. Commercially it is available as a bonding agent for bonding acrylic to porcelain and metal. The purpose of this investigation was to compare the adhesive effects of three adhesion promoters utilizing three different restorative resins to human permanent enamel.
Materials and methods.
bedded in acrylic bases and prepared in the following manner: Surfaces were cleaned with a slowly-rotating prophylaxis cup and a non-fluoridated pumice slurry; the teeth were rinsed with distilled water, dried, and etched with 50% phosphoric acid with 7% zinc-oxide buffer, rinsed for one minute with distilled water, and dried for one minute with compressed oil-free air. A pressure-sensitive adhesive-backed paper was punched with three holes of .010 inch diameter which acted as a template for resin attachment. This template insured that each resin sample tested would have the same resin enamel surface contact area and also limited the resin sample to the enamel area which received a particular treatment. One of the three treatment areas on the tooth specimen was then randomly assigned to receive one of three adhesion promoters or control and one of the three resins. Figure 1 shows a typical treatment combination. The adhesion promoters were applied with a cotton pellet immediately before the assigned resin was mixed to manufacturer's specifications and applied to the treatment area. The resin was applied by tamping it into a 0.1 25 inch diameter plastic tube, placing the tube over the treatment area, and condensing the resin against the enamel surface with a wooden dowel which acted as a plunger. The samples were stored in 100% humidity for twenty-four hours at
Twelve variables were examined in a completely crossed 3 x 4 experimental design. They were the use of one of three commercially available coupling agents on a control area and the use of one of three 370C. The resin-enamel bond strengths were restorative resins on an acid-etched enamel then determined with the use of an Instron surface. The adhesion promoters were a universal testing machine at a cross head butylacrylate-polycarboxyl type, an NPG- speed of 0.05 inches per minute (Figure 2). GMA type, a silane type, or a control sur- An orthodontic wire loop was attached to face where no adhesion promoter was used. the fixed arm of the testing device, with The resins used were Cervident*, Simulate* * the free end placed around the resin or Vytol***. Ten specimens were examined to be tested. The loop was placed sample at the for each possible treatment combination, resin-enamel interface to insure that the test resulting in a total of 120 specimens. forces were parallel to the enamel surface Recently-extracted, human, caries-free and resulted in a pure shear force. Forces permanent mandibular incisors were em- required to dislodge the resin specimens were recorded. The results were compared an analysis of variance. utilizing +Simulate Adhesion Promoter, Kerr Sybron Corp., Romulus, Mich. ++Cervident Adhesion Promoter, Pennwalt S.S. White Corp., Philadelphia, PA +++Fusion, George Taub Products and Fusion Co., Inc., Jersey City, N.J. *Pennwalt S.S. White, Philadelphia, PA **Kerr Sybron Corp., Romulus, Mich. ***L. D. Caulk Co., Milford, Delaware
Results. The measured retentive strengths indicated adhesive failures between resin and enamel. Specimens were examined, and none had resin remaining, which would indicate
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
Vol 58 No 4
ADHESION EFFECTS OFADHESIONPROMOTERS
1373
Typical Treatment Combination
1 Minute H3P0Q Etch Fig. l.-Typical Treatment Combination.
Assembly For Shea r Testin9 Load Cell
-
Looped Wire 1 Mkvt Hi,PQ Etch
Fig. 2. -Assembly for Shear Testing. Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
1374
J Dent Res April 1979
JEDR YCHOWSKI ETAL.
Collective
Shear
Stren9ths
MII SILANE * UTYL ACRYLATE POLYCOXYL o CONTROL r NtG-M STMDARD ERROR OF MEAN
O A%
'a
CERVIDENT
SIMULATE
VYTOL
Fig. 3. -Collective Shear Strengths, Grouped by Resin Type.
cohesive failure within the resin. The results of the analysis of variance (Table 1) demonstrated a significant primer effect of the p < .01 probability level. There was no significant effect from the type of resin utilized or from the interaction of primer and resin as demonstrated in the interaction term. Figure 3 depicts mean shear strengths for each treatment combination, grouped by the three resins utilized. There were no reversal trends for each resin type and, although there were no significant differences between resin types, the Cervident resin displayed slightly higher values for each of the primer types and the control groups than the Simulate or Vytol resins. Figure 4 shows combined mean values for each type of adhesion promoter. Sheffe's method demonstrated that the NPG-GMA adhesion promoter was significantly different from the average of the silane, butylacrylate-polycarboxyl, and control groups at
the p < .01 significance level. As mentioned previously, the resin-adhesion promoter combinations were randomly assigned to incisal, middle, or gingival thirds of the test specimens. There was no statistically significant relation between location on the test specimen and resistance to shear strengths.
TABLE 1 ANOVA SUMMARY TABLE Source
DF
MS
F Value
Primer (P) Resin (R) PXR Error
3 2 6 88
2327461
4.20* 2.12 0.27
117304 152048 554489
*p < .01
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
Vol S8 No 4
ADHESION EFFECTS OF ADHESION PROMOTERS
Combined Shear Strengths 1816-
14c
12-
g
1375
face changes. No effect could be demonstrated between resins attached to incisal, middle, or gingival thirds. A method is still needed to examine resins attached to enamel which is prepared or fractured parallel to enamel rods.
10-
Conclusions.
a 8A
64-
20-
altiEt
Ulllll
Fig. 4.-Combined Shear Strengths, Demonstrating a Significant (p < .01) Difference Between the NPG-GMA Adhesion Promoter and all Other Treatment Combinations.
Discussion. The present study investigated only those adhesion promoters available commercially that could be easily used by the dental practitioner. The results demonstrated a significant adhesive effect only when the NPGGMA adhesion promoter was utilized. No differences were demonstrated between the butylacrylate-polycarboxyl type, the silane type, or control specimens which were not pretreated with an adhesion promoter. The three resins utilized in this study were filled resins, the Cervident resin being a liqcuid-powder type while the Simulate and Vytol resins are two-part paste systems. The liquid-powder system, due to its low viscosity and angle of contact, might be expected to affect retentive strengths; however, type of resin did not influence retention, so choice of a filled resin could be influenced by color stability, marginal integrity, working and finishing properties. Synthesis of an ideal adhesion promoter would enable the clinician to place restorations, sealants, veneers, etc., with greater confidence in adhesive properties. Mechanical preparation, such as beveling or scalloping, to increase the area for adhesion could be eliminated. The labial tooth surface subjected to adhesive bonding in this study certainly does not represent all possible enamel surfaces which the clinician must restore, seal, or veneer. Labial surfaces differ in enamel crystallite orientation as location on the sur-
The effects of three adhesion promoters on shear strengths of three filled resins were compared. All resins separated from enamel specimens without evidence of cohesive resin failure. Location of the resins on labial tooth surfaces did not affect shear strengths, so placement of resins at gingival, middle, or incisal locations did not influence retention. Of the three resins compared, none influenced resistance to shear strength. The NPGGMA type of adhesion promoter significantly increased resin retention; however, no differences could be demonstrated between the butylacrylate-polycarboxyl type, the silane type, or control resins which were not pretreated with an adhesion promoter. Further investigation is required to examine the effects of adhesion promoters on resindentin bonding and the effects of newlydeveloped adhesion promoters.
Acknowledgment. The authors wish to express their thanks to the Word Processing Center, Irene Petravicius of the Dental Illustration Dept., School of Dentistry, and P. Schroth, Computing Resources Group, UCLA, M.R.R.C. REFERENCES 1. BRAUER, G. M.: Adhesion and Adhesives, in VON FRAUNHOFER, J. A. (ed.): Scientific Aspects of Dental Materials, London: Butterworths, 1975, pp. 49-96. 2. KRAMER, I.; and LEE, K. W.: The Demonstration of Glycerophosphoric Acid Dimethacrylate in Dentine and Filling Material Following the Use of a Cavity Sealer. J. Dent Res. 39:1003, 1960. 3. DRIESSENS, F. C. M.; BRAUER, G. M.; and TERMINI, D. J.: Chelating Agents as Potential Adhesives for Dental Restorations. J. Dent. Res., Program and Abstracts of Papers, 47th General Meeting, International Association for Dental Research, Abstract #137, 1969. 4. LEE, H.: Adhesion Between Lining Tissue and Plastics 1. Adhesion of Epoxy and Poly-
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
1376
J Deti t Res April 1 9 79
JEDR YCHO WSKI ET A L.
urethane Resins to Dentin and Enamel. J. Biomed. Mater. Res. 3:349, 1969. 5. ANTONUCCI, J. M.; and BOWEN, R. L.: Adhesive Bonding of Various Materials to Hard Tooth Tissues: XIII. Synthesis of a Polyfunctional Surface-Active Amine Accelerator. J. Dent. Res. 56(8):937-942, 1977. 6. FARLEY, E. P.; JONES, R. L.; and ANBAR, M.: Improved Adhesion of Acrylic Restoration Materials to Dental Enamel by Precoating With Monomers Containing Phosphonate Groups. J. Dent. Res. 56(8):943-952, 1977. 7. MISRA, D.; and BOWEN, R.: Adsorption of NPG-GMA on Hydroxyapatite, J. Dent. Res. 55:Abstract # 327, 1976.
8. SMUTKA, S.; JEDRYCHOWSKI, J.; and CAPUTO, A. A.: An Evaluation of Primary Enamel Pretreatments and Their Effects on Resin Retention, J. Denit Res. 57(7-8):796799, 1978. 9. CHARBENEAU, G. T.; DENNISON, J. B.; RYGE, G.: A Filled Pit and Fissure Sealant: 18 Month Results. JADA . 95:299-306, 1977. 10. BOWEN, R. L.: Adhesive Bonding of Various Material to Hard Tooth Tissues. II. Bonding to Dentin Promoted by a Surface-Active Comonomer. J. Dent. Res. 44:895, 1965. 11. MILLER, R. G.: Simultaneous Statistical Inference, New York, McGraw-Hill, 1966, p. 57.
CONFERENCE ANNOUNCEMENT CONFERENCE TO BE HELD ON MODELING TECHNIQUES AND APPLICATIONS IN DENTISTRY A four-day national conference on modeling of the dental delivery system in the U.S. and utilization of modeling as a dental manpower planning tool will be convened on July 16-19, 1979 at Northwestern University. The conference is designed to create an opportunity for developers of dental models, actual and potential users of those models, and dental planners, economists, and researchers to become familiar with current and future dental modeling activities. The objectives of the conference will be accomplished through a series of presentations and discussions by experts within the following topic areas: 1) single equation models of the dental sector; 2) national dental forecasting and dental policy and analysis models; 3) applications of State and regional dental models for planning; and 4) dental practice simulation models. A variety of techniques, applications, and viewpoints will be represented. Participants will include representatives of Federal agencies, other health planners, methodologists, economists, dental researchers, and health policy makers. Researchers from various health disciplines are invited to attend. The conference is being sponsored by The Bureau of Health Manpower, Health Resources Administration. For further information, contact Resources for Health, Education, and Communications, Inc., 962 Wayne Avenue, Suite 701, Silver Spring, MD 20910.
Downloaded from jdr.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 26, 2015 For personal use only. No other uses without permission.
