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Acta Odontologica Scandinavica Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/iode20
Effect of dentin adhesives on contraction of restorative resins in cavities surrounded by acid-etched enamel Paulo Amarante de Araujo a
ab
& Erik Asmussen
ab
University of São Paulo, Bauru, Brazil
b
Royal Dental College, Copenhagen, Denmark Published online: 23 May 2015.
To cite this article: Paulo Amarante de Araujo & Erik Asmussen (1990) Effect of dentin adhesives on contraction of restorative resins in cavities surrounded by acid-etched enamel, Acta Odontologica Scandinavica, 48:5, 333-336 To link to this article: http://dx.doi.org/10.3109/00016359009033625
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Effect of dentin adhesives on contraction of restorative resins in cavities surrounded by acid-etched enamel Paulo Amarante de Araujo and Erik Asmussen University of SBo Paulo, Bauru, Brazil, and Royal Dental College, Copenhagen, Denmark
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
Amarante de Araujo P, Asmussen E. Effect of dentin adhesives o n contraction of restorative resins in cavities surrounded by acid-etched enamel. Acta Odontol Scand 1990;48:333-336. Oslo. ISSN 0001-6357. Enamel-surrounded cavities prepared in extracted human teeth were treated with an enamelbonding agent, one of two commercial dentin adhesives (Scotchbond 2 and Tenure), or one of two recent modifications of the Gluma system. In all cases the enamcl margins were subjected to some form of acid etching. The cavities were tilled with one of two different light-cured posterior resins, and the wall-to-wall polymerization contraction was asscssed in the enamel surface level and, after grinding, measured and presented as linear shrinkage in the dentin surface level. The linear shrinkage varicd from 0.66% in the control group, in which only composite resin was applied, to 0.28% in a group in which the cavities were pretreated with a dentin adhesive. N o difference could be demonstrated between the dentin adhesives or between the dentin adhesives and the enamel-bonding agent. 0 Composite resins; denlal rna,crials; in riilro study; linear contraction; marginal adaptation
Erik Asmussen, Department of Denial Materiuls and Technology, Royal Dentul Collegr. Ndrrr Alle 20, DK-2200 Copenhagen N , Denmark
It is universally recognized that composite resin filling materials shrink during polymerization, making the restorations SUSceptible to marginal leakage. In a recent study of bonding mediated by the Gluma system (Bayer AG, FRG), Araujo & Asmussen (1) demonstrated that a strong adhesion can be obtained when the dentin and enamel surfaces are pretreated with an aluminum oxalate/glycine solution (AO/gly). In another study the same authors (2) introduced modifications in the Gluma resin developed by Asmussen et al. in 1988 (3). These modifications promoted strong adhesion to dentin.
The purpose of the present study was to investigate the effect of two commercial adhesives, Scotchbond 2 (3M Co., USA) and Tenure (Den-Mat Corp., USA), and of two modifications of the above-mentioned Giuma system on the adaptation of two posterior composite resins to the walls of cavities surrounded by etched enamel.
Materials and methods The materials of commercial origin listed in Table 1 were used in the present investigation. The pretreatment for the Gluma
Table 1. List of the commercial materials used in the investigation Brand
Batch no.
Manufacturer
Scotchgel (etchant) Silux Enamel Bond Resin (SEB) Scotchbond 2 Tenure P-50-U Estilux Posterior-L
X C R 28 4F1 E81HO8 11,400.20 UF 4P 3 1-12-89-173
3M Co.. USA 3M Co., USA 3M Co., USA Den-Mat Corp., USA 3M Co., USA Kulzer, FRG
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
334 P. Amarunte de Aruujv
& E. Asmussen
system (AO/gly) has been described earlier (1). It consisted of an aqueous mixture of aluminum oxalate (5.0% w/w) and oxalic acid (2.5% w/w) with about 3% w/w of glycine added to give a pH of 1.25. The modified Gluma (Gluma resin) has likewise been described earlier (2). It contained glutaraldehyde (2.5% w/w), 2-hydroxyethyl methacrylate (HEMA) (17% w/w), bisphenol-Aglycidyl methacrylate (BISGMA) (5% w/w), water (24.5% w/w), tetrahydrofuran (48% w/w), acetic acid (3% w/w), and camphorquinone (0.1% w/w). The method has been described in a previous paper (4). In brief, the procedures were as follows: The investigation was carried out using extracted human teeth. Only molar teeth with at least one sound, lateral surface were used. After extraction the teeth were cleaned mechanically and stored in a 1% chloramine-T solution (Struers A/S, Denmark) at room temperature (5). One of the lateral surfaces of the tooth crown was ground on wet carborundum paper no. 220 (Struer A/S) such that a flat enamel surface was obtained. Butt-joint cavities, 4 mm long, 3 mm wide, and 2 mm deep, were prepared. A cylindrical diamond bur (diameter, 1 mm) Table 2. The various treatment procedures Treatment
Procedure
A
Control: acid etching of enamel and placement of composite resin Acid etching of enamel, application of SEB*. and placement o f composite resin Pretreatment o l cavity with AO/gly solution, application of SER, and placement of composite resin Pretreatment of cavity with AO/gly solution, application of Gluma, application of SEB, and placement of composite resin Pretreatment of cavity with AO/gIy solution, application of G l u m resin. and placement of composite resin Acid etching of enamel, application of Scotchbond 2, and placement of composite resin Application of Tenure dentin bonding system and placement of composite resin
B C D
E F G
* SEB = Silux Enamel Bond Resin.
ACTA ODONTOL SCAND 48 (1990)
in a high-speed water-cooled turbine handpiece was used to set up the outline of the preparation, and a non-crosscut straight fissure bur (diameter, 1.5 mm) with low speed was used to perform the final cutting of the cavities. In all cases the bottom of the cavity was beneath the enamel-dentin junction. The cavities were dried with a blast of air and then received one of the treatments described in Table 2. After the treatment the composite reqin was placed in the cavity, and its free surface covered with Hawe-Neos matrix with pressure. The resin was illuminated with a Visilux-2 lamp (3M Co.) for 60sec with the exit window in contact with the strip. Five cavities were used for each experimental condition. All procedures were carried out at room temperature (22 2°C). The commercial products were used in accordance with the manufacturers' instructions. The solutions for the Gluma system were applied as previously described (1, 2).
*
Eiiumel surfuce obseruation After the polymerization a standardized method of gentle wet grinding and polishing was performed, removing the filling surplus until the total periphery of the surrounding enamel was uncovered. The margin was inspected in a Leitz Orthoplan microscope (8 x 80), and the presence or absence of gaps was recorded.
Dentin surface observation After the enamel surface observation the teeth were gently ground under water on carborundum paper and with paper no. 1000 at the final stage approximately parallel to the free surface of the filling until all enamel was removed. The plane surface was then polished. The margin was inspected in the microscope, and the gap widths measured by means of a measuring ocular. The gaps were measured in less than 2 min, to minimize any effect of evaporation of water from the specimen (4).Gaps as small as 1 pm could be measured. The gaps were then expressed in percentage of the cavity length or width, depending on the location of the gap. The
Dentin adhesives in acid-etched cavities
ACTA ODONTOL SCAND 48 (1990)
niaximum polymerization contraction gap in percentage (PCG %) was recorded for each of the investigated fillings.
Results
i il
PCG %
0.3
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
335
T
:Ili
At the enamel level of the cavities a con- 0.2 traction gap was always observed. The gaps A were associated with fractures of the enamel 0.1 margins. These fractures made it impossible B C D E F G to measure the widths of the gaps with any degree of accuracy. Fig. 2. Polymerization contraction gaps (PCG %) of At the dentin level of the cavities, gaps P-50 for treatments A to G. The bars on top of each were observed that could be measured in the column represent the standard deviations. microscope. The results of the measurements are shown in Fig. 1 for Estilux Posterior and in Fig. 2 for the P-50. Analyses of variance these fractures are reduced when the finof the results shown in Figs. 1 and 2 were ishing and the polishing of the restorations performed. The analysis showed for both are postponed until after the shrinkage gaps composite resins that the results for treat- are closed as a consequence of water absorpments B to G are not statistically different tion by the resin. In the present study the ( p > 0.05), whereas treatment A gave finishing of the restorations was done 10 min results statistically different from the other after the polymerization of the resin, and this fact is probably responsible for the contreatments ( p < 0.001). stantly occurring fractures observed on the enamel margins of the cavities. The measurements of the gaps were done on the dentin Discussion surface of the cavities at a level of 800 to Asmussen & J ~ r g e n s e n(5) and J ~ r g e n s e net 1OOOym below the original surface of the al. (6) demonstrated that the polymerization restorations; it is known from studies by contraction of composite resins applied in Hansen (7) that a larger contraction is found etched enamel cavities produces fractures in in the deeper parts of the fillings. Hansen & Asmussen (8) and Hansen (9) the enamel margins of the cavity and that demonstrated that the marginal gaps for a resin are reduced when an Enamel Bond resin is used. This is in agreement with the PCG % better results obtained in condition B, in 0.7 which the Silux Enamel Bond was used, as compared to the results in condition A , in which the Enamel Bond was not used. The present study did not show any advantage of dentin adhesives compared with the 0.3 use of a ‘simple’ enamel bonding agent. 0.2 Thus, dentin adhesives may not increase the 0.1 quality of restorations of composite resin in A cavitites surrounded by acid-etched enamel. B C D E F C Further, the results imply that dentin adhesives are mainly indicated for prepFig. 1. Polymerization contraction gaps (PCG %) of arations that have part of the margin located Estilux Posterior for treatments A to G. The bars on in dentin or cementum. top of each column represent the standard deviations.
1
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
336 P. Arniirunie de Araujo
Ce E. Asmussen
It has been found that all present-day restorative resins shrink during polymerization, and no commercial dentin-bonding agent is able to prevent this shrinkage (8-10). This is in agreement with the results of the present investigation. As the present-day dentin adhesives have proved unable to prevent the gap formation around composite resin restorations, two procedures may be suggested: 1) postponement of polishing of the marginal area until contraction gaps are closed by hygroscopic expansion and not just for 5 , 10, or 60min (lo), and 2) the use of impregnation of the gap by low-viscous, non-composite resins, as has been suggested by some authors (11,12).
References I . Araujo PA, Asmusscn E . Aluminum oxalate/glycine solutions as pretreatment in the Gluma bonding system. Scand J Dent Res 1989;97:552-8. 2. Araujo PA, Asmussen E. Bonding to dentin with a simplified Gluma system. Int Dent J 1989;39: 253-7. 3 . Asmussen E. Antonucci JM, Bowen RL. Adhesion
Received for publication 22 August 1989
ACTA ODONTOL SCAND 48 (1990)
to dentin by means of Gluma resin. Scand J Dent Res 1988;96:584-9. 4. Hansen EK. Visible light-cured composite rcsins: Polymerization contraction, contraction pattern and hygroscopic expansion. Scand J Dent Res 1982 ;90:329-35. 5. Asmussen E , Jdrgensen KD. A microscopic investigation of the adaptation of some plastic filling materials to dental cavity walls. Acta Odontol Scand 1972;30:3-21. 6. Jdrgensen KD, Asmussen E , Shimokobe H. Enamel damages caused by contracting restorative materials. Scand J Dent Res 1975;83:120-2. 7. Hansen EK. Contraction patterns of composite resins i n dentin cavities. Scand J Dent Res 1982;90:480-3. 8. Hansen EK, Asmussen E. Comparative study of dentin adhesives. Scand J Dent Res 1985;93:280-7. 9. Hanscn EK. Effect of three dentin adhesives on marginal adaptation of two light-cured composites. Scand J Dent Res 1986;94:82-6. 10. Hansen EK. Asmussen E. Effect of postponed polishing on marginal adaptation of resin used with dentin-bonding agent. Scand J Dent Res 1988; 96:260-4. 11. Qvist V. Marginal adaptation of composite restorations performed in vivo with different acid-etch restorative procedures. Scand J Dent Res 1985; 93:68-75. 12. Torstensen B , Brinnstriim M, Mattson B. A new method for sealing composite resin contraction gaps in lined cavities. J Dent Res 1985;64:450-3.
Acta Odontologica Scandinavica Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/iode20
Effect of dentin adhesives on contraction of restorative resins in cavities surrounded by acid-etched enamel Paulo Amarante de Araujo a
ab
& Erik Asmussen
ab
University of São Paulo, Bauru, Brazil
b
Royal Dental College, Copenhagen, Denmark Published online: 23 May 2015.
To cite this article: Paulo Amarante de Araujo & Erik Asmussen (1990) Effect of dentin adhesives on contraction of restorative resins in cavities surrounded by acid-etched enamel, Acta Odontologica Scandinavica, 48:5, 333-336 To link to this article: http://dx.doi.org/10.3109/00016359009033625
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Effect of dentin adhesives on contraction of restorative resins in cavities surrounded by acid-etched enamel Paulo Amarante de Araujo and Erik Asmussen University of SBo Paulo, Bauru, Brazil, and Royal Dental College, Copenhagen, Denmark
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
Amarante de Araujo P, Asmussen E. Effect of dentin adhesives o n contraction of restorative resins in cavities surrounded by acid-etched enamel. Acta Odontol Scand 1990;48:333-336. Oslo. ISSN 0001-6357. Enamel-surrounded cavities prepared in extracted human teeth were treated with an enamelbonding agent, one of two commercial dentin adhesives (Scotchbond 2 and Tenure), or one of two recent modifications of the Gluma system. In all cases the enamcl margins were subjected to some form of acid etching. The cavities were tilled with one of two different light-cured posterior resins, and the wall-to-wall polymerization contraction was asscssed in the enamel surface level and, after grinding, measured and presented as linear shrinkage in the dentin surface level. The linear shrinkage varicd from 0.66% in the control group, in which only composite resin was applied, to 0.28% in a group in which the cavities were pretreated with a dentin adhesive. N o difference could be demonstrated between the dentin adhesives or between the dentin adhesives and the enamel-bonding agent. 0 Composite resins; denlal rna,crials; in riilro study; linear contraction; marginal adaptation
Erik Asmussen, Department of Denial Materiuls and Technology, Royal Dentul Collegr. Ndrrr Alle 20, DK-2200 Copenhagen N , Denmark
It is universally recognized that composite resin filling materials shrink during polymerization, making the restorations SUSceptible to marginal leakage. In a recent study of bonding mediated by the Gluma system (Bayer AG, FRG), Araujo & Asmussen (1) demonstrated that a strong adhesion can be obtained when the dentin and enamel surfaces are pretreated with an aluminum oxalate/glycine solution (AO/gly). In another study the same authors (2) introduced modifications in the Gluma resin developed by Asmussen et al. in 1988 (3). These modifications promoted strong adhesion to dentin.
The purpose of the present study was to investigate the effect of two commercial adhesives, Scotchbond 2 (3M Co., USA) and Tenure (Den-Mat Corp., USA), and of two modifications of the above-mentioned Giuma system on the adaptation of two posterior composite resins to the walls of cavities surrounded by etched enamel.
Materials and methods The materials of commercial origin listed in Table 1 were used in the present investigation. The pretreatment for the Gluma
Table 1. List of the commercial materials used in the investigation Brand
Batch no.
Manufacturer
Scotchgel (etchant) Silux Enamel Bond Resin (SEB) Scotchbond 2 Tenure P-50-U Estilux Posterior-L
X C R 28 4F1 E81HO8 11,400.20 UF 4P 3 1-12-89-173
3M Co.. USA 3M Co., USA 3M Co., USA Den-Mat Corp., USA 3M Co., USA Kulzer, FRG
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
334 P. Amarunte de Aruujv
& E. Asmussen
system (AO/gly) has been described earlier (1). It consisted of an aqueous mixture of aluminum oxalate (5.0% w/w) and oxalic acid (2.5% w/w) with about 3% w/w of glycine added to give a pH of 1.25. The modified Gluma (Gluma resin) has likewise been described earlier (2). It contained glutaraldehyde (2.5% w/w), 2-hydroxyethyl methacrylate (HEMA) (17% w/w), bisphenol-Aglycidyl methacrylate (BISGMA) (5% w/w), water (24.5% w/w), tetrahydrofuran (48% w/w), acetic acid (3% w/w), and camphorquinone (0.1% w/w). The method has been described in a previous paper (4). In brief, the procedures were as follows: The investigation was carried out using extracted human teeth. Only molar teeth with at least one sound, lateral surface were used. After extraction the teeth were cleaned mechanically and stored in a 1% chloramine-T solution (Struers A/S, Denmark) at room temperature (5). One of the lateral surfaces of the tooth crown was ground on wet carborundum paper no. 220 (Struer A/S) such that a flat enamel surface was obtained. Butt-joint cavities, 4 mm long, 3 mm wide, and 2 mm deep, were prepared. A cylindrical diamond bur (diameter, 1 mm) Table 2. The various treatment procedures Treatment
Procedure
A
Control: acid etching of enamel and placement of composite resin Acid etching of enamel, application of SEB*. and placement o f composite resin Pretreatment o l cavity with AO/gly solution, application of SER, and placement of composite resin Pretreatment of cavity with AO/gly solution, application of Gluma, application of SEB, and placement of composite resin Pretreatment of cavity with AO/gIy solution, application of G l u m resin. and placement of composite resin Acid etching of enamel, application of Scotchbond 2, and placement of composite resin Application of Tenure dentin bonding system and placement of composite resin
B C D
E F G
* SEB = Silux Enamel Bond Resin.
ACTA ODONTOL SCAND 48 (1990)
in a high-speed water-cooled turbine handpiece was used to set up the outline of the preparation, and a non-crosscut straight fissure bur (diameter, 1.5 mm) with low speed was used to perform the final cutting of the cavities. In all cases the bottom of the cavity was beneath the enamel-dentin junction. The cavities were dried with a blast of air and then received one of the treatments described in Table 2. After the treatment the composite reqin was placed in the cavity, and its free surface covered with Hawe-Neos matrix with pressure. The resin was illuminated with a Visilux-2 lamp (3M Co.) for 60sec with the exit window in contact with the strip. Five cavities were used for each experimental condition. All procedures were carried out at room temperature (22 2°C). The commercial products were used in accordance with the manufacturers' instructions. The solutions for the Gluma system were applied as previously described (1, 2).
*
Eiiumel surfuce obseruation After the polymerization a standardized method of gentle wet grinding and polishing was performed, removing the filling surplus until the total periphery of the surrounding enamel was uncovered. The margin was inspected in a Leitz Orthoplan microscope (8 x 80), and the presence or absence of gaps was recorded.
Dentin surface observation After the enamel surface observation the teeth were gently ground under water on carborundum paper and with paper no. 1000 at the final stage approximately parallel to the free surface of the filling until all enamel was removed. The plane surface was then polished. The margin was inspected in the microscope, and the gap widths measured by means of a measuring ocular. The gaps were measured in less than 2 min, to minimize any effect of evaporation of water from the specimen (4).Gaps as small as 1 pm could be measured. The gaps were then expressed in percentage of the cavity length or width, depending on the location of the gap. The
Dentin adhesives in acid-etched cavities
ACTA ODONTOL SCAND 48 (1990)
niaximum polymerization contraction gap in percentage (PCG %) was recorded for each of the investigated fillings.
Results
i il
PCG %
0.3
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
335
T
:Ili
At the enamel level of the cavities a con- 0.2 traction gap was always observed. The gaps A were associated with fractures of the enamel 0.1 margins. These fractures made it impossible B C D E F G to measure the widths of the gaps with any degree of accuracy. Fig. 2. Polymerization contraction gaps (PCG %) of At the dentin level of the cavities, gaps P-50 for treatments A to G. The bars on top of each were observed that could be measured in the column represent the standard deviations. microscope. The results of the measurements are shown in Fig. 1 for Estilux Posterior and in Fig. 2 for the P-50. Analyses of variance these fractures are reduced when the finof the results shown in Figs. 1 and 2 were ishing and the polishing of the restorations performed. The analysis showed for both are postponed until after the shrinkage gaps composite resins that the results for treat- are closed as a consequence of water absorpments B to G are not statistically different tion by the resin. In the present study the ( p > 0.05), whereas treatment A gave finishing of the restorations was done 10 min results statistically different from the other after the polymerization of the resin, and this fact is probably responsible for the contreatments ( p < 0.001). stantly occurring fractures observed on the enamel margins of the cavities. The measurements of the gaps were done on the dentin Discussion surface of the cavities at a level of 800 to Asmussen & J ~ r g e n s e n(5) and J ~ r g e n s e net 1OOOym below the original surface of the al. (6) demonstrated that the polymerization restorations; it is known from studies by contraction of composite resins applied in Hansen (7) that a larger contraction is found etched enamel cavities produces fractures in in the deeper parts of the fillings. Hansen & Asmussen (8) and Hansen (9) the enamel margins of the cavity and that demonstrated that the marginal gaps for a resin are reduced when an Enamel Bond resin is used. This is in agreement with the PCG % better results obtained in condition B, in 0.7 which the Silux Enamel Bond was used, as compared to the results in condition A , in which the Enamel Bond was not used. The present study did not show any advantage of dentin adhesives compared with the 0.3 use of a ‘simple’ enamel bonding agent. 0.2 Thus, dentin adhesives may not increase the 0.1 quality of restorations of composite resin in A cavitites surrounded by acid-etched enamel. B C D E F C Further, the results imply that dentin adhesives are mainly indicated for prepFig. 1. Polymerization contraction gaps (PCG %) of arations that have part of the margin located Estilux Posterior for treatments A to G. The bars on in dentin or cementum. top of each column represent the standard deviations.
1
Downloaded by [University of Sydney Library] at 03:52 16 August 2015
336 P. Arniirunie de Araujo
Ce E. Asmussen
It has been found that all present-day restorative resins shrink during polymerization, and no commercial dentin-bonding agent is able to prevent this shrinkage (8-10). This is in agreement with the results of the present investigation. As the present-day dentin adhesives have proved unable to prevent the gap formation around composite resin restorations, two procedures may be suggested: 1) postponement of polishing of the marginal area until contraction gaps are closed by hygroscopic expansion and not just for 5 , 10, or 60min (lo), and 2) the use of impregnation of the gap by low-viscous, non-composite resins, as has been suggested by some authors (11,12).
References I . Araujo PA, Asmusscn E . Aluminum oxalate/glycine solutions as pretreatment in the Gluma bonding system. Scand J Dent Res 1989;97:552-8. 2. Araujo PA, Asmussen E. Bonding to dentin with a simplified Gluma system. Int Dent J 1989;39: 253-7. 3 . Asmussen E. Antonucci JM, Bowen RL. Adhesion
Received for publication 22 August 1989
ACTA ODONTOL SCAND 48 (1990)
to dentin by means of Gluma resin. Scand J Dent Res 1988;96:584-9. 4. Hansen EK. Visible light-cured composite rcsins: Polymerization contraction, contraction pattern and hygroscopic expansion. Scand J Dent Res 1982 ;90:329-35. 5. Asmussen E , Jdrgensen KD. A microscopic investigation of the adaptation of some plastic filling materials to dental cavity walls. Acta Odontol Scand 1972;30:3-21. 6. Jdrgensen KD, Asmussen E , Shimokobe H. Enamel damages caused by contracting restorative materials. Scand J Dent Res 1975;83:120-2. 7. Hansen EK. Contraction patterns of composite resins i n dentin cavities. Scand J Dent Res 1982;90:480-3. 8. Hansen EK, Asmussen E. Comparative study of dentin adhesives. Scand J Dent Res 1985;93:280-7. 9. Hanscn EK. Effect of three dentin adhesives on marginal adaptation of two light-cured composites. Scand J Dent Res 1986;94:82-6. 10. Hansen EK. Asmussen E. Effect of postponed polishing on marginal adaptation of resin used with dentin-bonding agent. Scand J Dent Res 1988; 96:260-4. 11. Qvist V. Marginal adaptation of composite restorations performed in vivo with different acid-etch restorative procedures. Scand J Dent Res 1985; 93:68-75. 12. Torstensen B , Brinnstriim M, Mattson B. A new method for sealing composite resin contraction gaps in lined cavities. J Dent Res 1985;64:450-3.
