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Measurement of adsorption of salivary proteins onto soft denture lining materials
Measurement of adsorption of salivary proteins onto soft denture lining materials Yohji Imai, PhD,a and Yoh Tamaki, DDSb Institute for Medical and Dental Engineering, Tokyo Medical and Dental University, Tokyo, Japan Statement of problem. The adhesion of Candida albicans to soft liners is a major causative factor in denture stomatitis. It has been suggested that salivary proteins play an important role in this candidal adhesion. Purpose. This study measured the adsorption of salivary proteins on soft liners. Material and methods. Five commercial materials and 1 experimental material were immersed in saliva, albumin solution, or milk. Proteins adsorbed on the material surfaces were measured by ATR/FT-IR spectroscopy. Results. The amount of proteins adsorbed to the 6 materials varied considerably. Protein adsorption was significantly lower in the experimental fluoropolymer and polyphosphazene, and higher in acrylic resin and silicone. Conclusion. Different soft liners promote adsorption of varying amounts of protein. (J Prosthet Dent 1999;82:348-51.)
CLINICAL IMPLICATIONS Differing amounts of proteinaceous materials are adsorbed from saliva and diet on soft liners, depending on the materials used. Adsorbed proteins can affect Candida albicans adhesion and may lead to denture stomatitis. Therefore, it is suggested that an appropriate material should be selected to prevent denture stomatitis.
D
enture soft lining materials are widely used for the treatment and prevention of local areas of soreness under dentures. However, one serious problem associated with the use of soft liners is denture stomatitis. Soft liners are known to be easily colonized and deeply infected by Candida albicans and its hyphate.1-7 The presence of C albicans on the denture surface is considered a major causative factor in denture stomatitis.8-11 In candidal adhesion, proteins have been suggested to play an important role12-15: The pellicle of the whole salivary proteins on denture materials may bind to C albicans13; serum or saliva coating of an acrylic resin surface affects candidal adhesion15; and denture pellicle derived from saliva and/or serum proteins promotes C albicans colonization and hyphal invasion of the denture lining material.16 Despite the anticipated effect of saliva and proteins on candidal adhesion or Candida-associated, denture-induced stomatitis, few studies of the amount of protein adsorbed on soft liners have been conducted. Therefore, the purpose of this study was to measure the adsorption of proteins on soft liners in saliva and other proteinaceous solutions by attenuated total reflection (ATR)/Fourier Transform infrared (FT-IR) spectroscopy on 5 commercial materials and 1 experimental material. aProfessor, bGraduate
Division of Biofunctional Materials. Student, Division of Biofunctional Materials.
348 THE JOURNAL OF PROSTHETIC DENTISTRY
MATERIAL AND METHODS The 6 lining materials used in this study are listed in Table I. All commercial materials were processed according to the manufacturers’ directions. The experimental soft lining material was composed of a fluoropolymer and poly methacrylate/acrylate, and was prepared as follows: 70% of vinylidene fluoride/hexafluoropropylene copolymer (Daiel G801, Daikin Kogyo Co, Osaka, Japan) was mixed with 30% monomer mixtures, which consisted of ethyl methacrylate (17.85%), 2-ethylhexyl acrylate (10%), pentaerythritol tetraacrylate (1.5%), N,N-dimethylaminoethyl methacrylate (0.15%), and camphorquinone (0.5%). The mixed compound was sandwiched between 2 glass plates with a 1-mm spacer, then photopolymerized in a visible light-curing apparatus (α-Light, Morita Co, Tokyo, Japan) for 10 minutes. Cured material was separated from the glass plates and was photopolymerized for another 10 minutes.
Measurement of protein adsorption Nine specimens (8 × 30 × 1 mm) for each material were cut from the sample sheets prepared. Specimens were immersed in human saliva, 4.5% bovine albumin (fraction V powder, Sigma, St Louis, Mo.)/phosphate buffered saline solution (PBS), or milk (containing 3.5% fat, Snow Brand Milk Co, Tokyo, Japan) at 37°C for 15 minutes. Specimens were rinsed in distilled water for 15 seconds to remove unadsorbed proteins and dried in a VOLUME 82 NUMBER 3
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THE JOURNAL OF PROSTHETIC DENTISTRY
Table I. Materials used in this study Code
Material
Nov Mol Kur Eva Ast Exp
Type
Novus Molteno Kurepeet Evatouch Astron LCS Experimental
Polyphosphazene Phoyolefin Fluoropolymer Silicone Acrylic resin Fluoropolymer
Table II. Absorbance before and after adsorption of proteins (×10–3) Proteinaceous solution Material
Nov Mol Kur Eva Ast Exp
Saliva
6.6 11.3 13.7 15.0 15.3 5.7
(0.6) (2.1) (1.5) (2.0) (0.6) (0.7)
Albumin/PBS
6.0 8.1 11.3 13.7 13.7 5.5
(0.9) (0.4) (1.5) (2.3) (1.2) (0.8)
Milk
6.8 14.0 7.5 14.7 21.7 4.5
(1.2) (2.0) (0.5) (2.5) (3.5) (0.9)
Number of samples: n = 3 Standard deviations are given in parentheses.
desiccator. The whole saliva used was collected from 1 of the authors immediately before the experiment. Surface analysis of the soft liners was performed by ATR/FT-IR spectroscopy. The instrument used (FT/IR 300E system, Jasco Co, Tokyo, Japan) was fitted with a 45-degree germanium prism (30 × 10 × 3 mm; 5 internal reflections). Infrared spectra of specimens before and after protein adsorption were taken at 4 cm–1 resolution and stored in the 300E memory for later use in a subtraction routine. The amount of adsorbed proteins, compared by absorbance at the amide I band (in the 1651-1655 cm–1 range), was obtained after subtraction of the spectrum of the virgin specimen from that of the protein-adsorbed specimen. The protein adsorption and the ATR/FT-IR measurements were made in triplicate using a new specimen and a fresh solution each time. The means and standard deviations of absorbance were calculated. Analysis of variance (ANOVA) was performed to compare the data and a statistical software package (StatView, Abacus Concepts, Berkeley, Calif.) was used to compute these values. A significant ANOVA result was followed by the Scheffé’s test. Statistical significance was set at P=.05.
RESULTS Figure 1 illustrates typical examples of the spectra before and after adsorption of proteins, and the subtracted spectrum. The subtracted spectrum exhibited amide I and II bands as a result of adsorbed proteins at SEPTEMBER 1999
Manufacturer
Hygenic Co, Akron, Ohio Molteno Co, Hiroshima, Japan Kureha Chemical Ind, Tokyo, Japan Neo Dental Chemical Products, Tokyo, Japan Astron Dental Co, Wheeling, Ill. The authors
Table III. Result of 2-way ANOVA Source
DF
F value
P value
Protein (P) Material (M) M×P
2 5 10
6.60 68.03 7.19
.0036 <.0001 <.0001
Table IV. Result of Scheffé’s test (Scheffé grouping) Proteinaceous solution Material
Saliva
Albumin/PBS
Milk
Nov Mol Kur Eva Ast Exp
AB ABCD BCD CDE DE A
A ABCD ABCD BCD BCD A
AB BCD ABC CDE E A
Same letters indicate that the mean values shown in Table II are not significantly different.
1653 and 1540 cm–1, respectively. Means and standard deviations of absorbance at the amide I band are presented in Table II. The amount of adsorbed protein showed considerable variation among the 6 materials. It was always minimal for the experimental material (Exp) and maximum for acrylic resin (Ast) in 3 proteinaceous solutions. Ast adsorbed 2.7, 2.5, and 4.8 times more proteins than Exp in saliva, albumin/PBS, and milk, respectively. Results of the 2-way ANOVA revealed that 2 main factors and their interaction had significant effects on absorbance (Table III). Because of the significance of the interaction between the 2 main factors, direct comparison of the data within each factor was difficult. Figure 2 illustrates the effect of interaction between the 2 factors. Although the 2 line graphs for saliva and albumin are almost parallel, which indicates no interaction, the line for milk crosses the other lines, indicating interaction. This finding suggests that the interaction was mainly caused by the different adsorption behavior of milk onto polyolefin (Mol), fluoropolymer (Kur), and Ast. 349
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IMAI AND TAMAKI
Fig. 2. Effects of proteins and materials on adsorption of protein expressed by adsorbance.
Fig. 1. IR spectra before (A) and after (B) adsorption of albumin on Mol. (C) shows results of spectral subtraction of (B) from (A).
Because of the interaction, 18 sets of data were subjected to 1-way ANOVA and post hoc Scheffé’s test. ANOVA resulted in significant differences (P<.0001). Table IV presents the result of the post hoc test. Adsorption of proteins to the Exp material and polyphosphazene (Nov) was significantly lower and was significantly higher for Ast and silicone (Eva). Mol exhibited high adsorption in milk but low adsorption in albumin/PBS. The protein adsorption on Kur was lower in milk than in saliva and albumin/PBS.
DISCUSSION The ATR/FT-IR technique has been a useful tool for investigating protein-material interactions.17 We applied this technique to measure protein adsorption onto 6 such materials in 3 proteinaceous solutions. In addition to saliva, albumin solution and milk were included in this study for comparative purposes because bovine albumin is a relatively pure protein that is easily available and milk is a popular drink that contains proteins. The amount of adsorbed protein demonstrated considerable variation among the 6 materials. Significantly lower adsorption of proteins in both the experimental material and polyphosphazene may be due to their unique composition or chemical structure. The former 350
was composed of a blend of a fluoropolymer and poly methacrylate/acrylate, which was formed by polymerization of the monomers during the curing process. The presence of the fluoropolymer is responsible for the low protein adsorption. In polyphosphazene, the phophazene structure itself is responsible for the low adsorption. Because of its special structure, polyphosphazene was included in this study, although Nov is not yet commercially available. The protein adsorption of Kur, a fluoropolymer, was significantly higher than that of the fluoropolymerbased experimental material. A possible explanation for this higher adsorption is that Kur is composed of a fluoromonomer, which is converted to fluoropolymer by polymerization. The resultant polymer does not appear to have characteristic properties of fluoropolymers. Only the oil-repellent property appears to be reflected in the relatively low protein adsorption in milk. Polyolefin material (Mol) exhibited higher adsorption of proteins in milk than in the other solutions. It is conceivable that the presence of lipids in the milk affected the protein adsorption because polyolefins usually have affinity to oily substances. Silicone (Eva) and acrylic resin (Ast) materials adsorbed more proteins, which may be correlated to the phenomena reported in the literature that more C albicans adheres to a silicone-based soft liner or acrylic resin-based tissue conditioner than to acrylic resin.5 Overall, the protein adsorption on the 6 materials in saliva and albumin/PBS was similar but it was different in milk (Fig. 2), although this conclusion may have limitations because of a single saliva source. This result leads to the following suggestions for evaluating protein adsorption: (1) albumin/PBS may be used as a model medium for saliva; and (2) different types of VOLUME 82 NUMBER 3
IMAI AND TAMAKI
medium such as milk containing lipids should be included to simulate an oral environment. The amount of adsorbed proteins varied considerably among the soft lining materials studied. The correlation between the amount of protein adsorption and C albicans adhesion should be investigated further. Nevertheless, less protein-adsorptive materials like fluoropolymers may be desirable for soft liners, because they absorb less water and oil, which results in less adhesion of dirt and microorganisms and, thus, fewer cases of colonization or development of bad odor.
CONCLUSION Within the limits of this study, the results demonstrated that the amount of proteins adsorbed onto the 6 materials studied was material-dependent. This finding suggests that C albicans adhesion could also be material-dependent. REFERENCES 1. Williamson JJ. The effect of denture lining materials on the growth of Candida albicans. Br Dent J 1968;125:106-10. 2. Allison RT, Douglas WH. Micro-colonization of the denture-fitting surface by Candida albicans. J Dent 1973;1:198-201. 3. Wright PS. The effect of soft lining materials on the growth Candida albicans. J Dent 1980;8:144-51. 4. Burns DR, Burns DA, DiPietro GJ, Gregory RL. Response of processed resilient denture liners to Candida albicans. J Prosthet Dent 1987;57:50711. 5. Okita N, Orstavik D, Orstavik J, Ostby K. In vivo and in vitro study on soft denture materials: microbial adhesion and tests for antibacterial activity. Dent Mater 1991;7:155-60. 6. Graham BS, Jones DW, Burke J, Thompson JP. In vivo fungal presence and growth on two resilient denture liners. J Prosthet Dent 1991;64:528-32. 7. Waters MG, Williams DW, Jagger RG, Lewis MA. Adherence of Candida albicans to experimental denture soft lining materials. J Prosthet Dent 1997;77:306-12.
SEPTEMBER 1999
THE JOURNAL OF PROSTHETIC DENTISTRY
8. Douglas WH, Walker DM. Nystatin in denture liners—an alternative treatment of denture stomatitis. Br Dent J 1973;135:55-9. 9. Davenport JC. The oral distribution of Candida in denture stomatitis. Br Dent J 1970;129:151-6. 10. Olsen I. Denture stomatitis: occurrence and distribution of fungi. Acta Odontol Scand 1974;32:329-33. 11. Makila E, Hopsu-Havu VK. Mycotic growth and soft denture lining materials. Acta Odontol Scand 1977;35:197-205. 12. Nikawa H, Iwanaga H, Kameda M, Hamada T. In vitro evaluation of Candida albicans adherence to soft denture-lining materials. J Prosthet Dent l992;68:804-8. 13. Nikawa H, Hamada T. Binding of salivary or serum proteins to Candida albicans in vitro. Arch Oral Biol 1990;35:571-3. 14. Samaranayake LP, McCourtie J, MacFarlane TW. Factors affecting the in vivo adherence of Candida albicans to acrylic surfaces. Arch Oral Biol 1980;25:611-5. 15. McCourtie J, MacFarlane TW, Samaranayake LP. Effect of saliva and serum on the adherence of Candida species to chlorhexidine-treated denture acrylic. J Med Microbiol 1986;21:209-13. 16. Nikawa H, Hyashi S, Nikawa Y, Hamada T, Samaranayake LP. Interaction between dentine lining material, protein pellicles and Candida albicans. Arch Oral Biol 1993;38:631-4. 17. Gendreau RM, Jakobsen RJ. Blood-surface interactions: Fourier transform infrared studies of protein adsorption from flowing blood plasma and serum. J Biomed Mater Res 1979;13:893-906.
Reprint requests to: DR YOHJI IMAI INSTITUTE FOR MEDICAL AND DENTAL ENGINEERING TOKYO MEDICAL AND DENTAL UNIVERSITY 2-3-10 KANDA-SURUGADAI TOKYO 101-0062 JAPAN FAX: 81-3-5280-8005 E-MAIL: [email protected] Copyright © 1999 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/99/$8.00 + 0. 10/1/98836
351
CLINICAL IMPLICATIONS Differing amounts of proteinaceous materials are adsorbed from saliva and diet on soft liners, depending on the materials used. Adsorbed proteins can affect Candida albicans adhesion and may lead to denture stomatitis. Therefore, it is suggested that an appropriate material should be selected to prevent denture stomatitis.
D
enture soft lining materials are widely used for the treatment and prevention of local areas of soreness under dentures. However, one serious problem associated with the use of soft liners is denture stomatitis. Soft liners are known to be easily colonized and deeply infected by Candida albicans and its hyphate.1-7 The presence of C albicans on the denture surface is considered a major causative factor in denture stomatitis.8-11 In candidal adhesion, proteins have been suggested to play an important role12-15: The pellicle of the whole salivary proteins on denture materials may bind to C albicans13; serum or saliva coating of an acrylic resin surface affects candidal adhesion15; and denture pellicle derived from saliva and/or serum proteins promotes C albicans colonization and hyphal invasion of the denture lining material.16 Despite the anticipated effect of saliva and proteins on candidal adhesion or Candida-associated, denture-induced stomatitis, few studies of the amount of protein adsorbed on soft liners have been conducted. Therefore, the purpose of this study was to measure the adsorption of proteins on soft liners in saliva and other proteinaceous solutions by attenuated total reflection (ATR)/Fourier Transform infrared (FT-IR) spectroscopy on 5 commercial materials and 1 experimental material. aProfessor, bGraduate
Division of Biofunctional Materials. Student, Division of Biofunctional Materials.
348 THE JOURNAL OF PROSTHETIC DENTISTRY
MATERIAL AND METHODS The 6 lining materials used in this study are listed in Table I. All commercial materials were processed according to the manufacturers’ directions. The experimental soft lining material was composed of a fluoropolymer and poly methacrylate/acrylate, and was prepared as follows: 70% of vinylidene fluoride/hexafluoropropylene copolymer (Daiel G801, Daikin Kogyo Co, Osaka, Japan) was mixed with 30% monomer mixtures, which consisted of ethyl methacrylate (17.85%), 2-ethylhexyl acrylate (10%), pentaerythritol tetraacrylate (1.5%), N,N-dimethylaminoethyl methacrylate (0.15%), and camphorquinone (0.5%). The mixed compound was sandwiched between 2 glass plates with a 1-mm spacer, then photopolymerized in a visible light-curing apparatus (α-Light, Morita Co, Tokyo, Japan) for 10 minutes. Cured material was separated from the glass plates and was photopolymerized for another 10 minutes.
Measurement of protein adsorption Nine specimens (8 × 30 × 1 mm) for each material were cut from the sample sheets prepared. Specimens were immersed in human saliva, 4.5% bovine albumin (fraction V powder, Sigma, St Louis, Mo.)/phosphate buffered saline solution (PBS), or milk (containing 3.5% fat, Snow Brand Milk Co, Tokyo, Japan) at 37°C for 15 minutes. Specimens were rinsed in distilled water for 15 seconds to remove unadsorbed proteins and dried in a VOLUME 82 NUMBER 3
IMAI AND TAMAKI
THE JOURNAL OF PROSTHETIC DENTISTRY
Table I. Materials used in this study Code
Material
Nov Mol Kur Eva Ast Exp
Type
Novus Molteno Kurepeet Evatouch Astron LCS Experimental
Polyphosphazene Phoyolefin Fluoropolymer Silicone Acrylic resin Fluoropolymer
Table II. Absorbance before and after adsorption of proteins (×10–3) Proteinaceous solution Material
Nov Mol Kur Eva Ast Exp
Saliva
6.6 11.3 13.7 15.0 15.3 5.7
(0.6) (2.1) (1.5) (2.0) (0.6) (0.7)
Albumin/PBS
6.0 8.1 11.3 13.7 13.7 5.5
(0.9) (0.4) (1.5) (2.3) (1.2) (0.8)
Milk
6.8 14.0 7.5 14.7 21.7 4.5
(1.2) (2.0) (0.5) (2.5) (3.5) (0.9)
Number of samples: n = 3 Standard deviations are given in parentheses.
desiccator. The whole saliva used was collected from 1 of the authors immediately before the experiment. Surface analysis of the soft liners was performed by ATR/FT-IR spectroscopy. The instrument used (FT/IR 300E system, Jasco Co, Tokyo, Japan) was fitted with a 45-degree germanium prism (30 × 10 × 3 mm; 5 internal reflections). Infrared spectra of specimens before and after protein adsorption were taken at 4 cm–1 resolution and stored in the 300E memory for later use in a subtraction routine. The amount of adsorbed proteins, compared by absorbance at the amide I band (in the 1651-1655 cm–1 range), was obtained after subtraction of the spectrum of the virgin specimen from that of the protein-adsorbed specimen. The protein adsorption and the ATR/FT-IR measurements were made in triplicate using a new specimen and a fresh solution each time. The means and standard deviations of absorbance were calculated. Analysis of variance (ANOVA) was performed to compare the data and a statistical software package (StatView, Abacus Concepts, Berkeley, Calif.) was used to compute these values. A significant ANOVA result was followed by the Scheffé’s test. Statistical significance was set at P=.05.
RESULTS Figure 1 illustrates typical examples of the spectra before and after adsorption of proteins, and the subtracted spectrum. The subtracted spectrum exhibited amide I and II bands as a result of adsorbed proteins at SEPTEMBER 1999
Manufacturer
Hygenic Co, Akron, Ohio Molteno Co, Hiroshima, Japan Kureha Chemical Ind, Tokyo, Japan Neo Dental Chemical Products, Tokyo, Japan Astron Dental Co, Wheeling, Ill. The authors
Table III. Result of 2-way ANOVA Source
DF
F value
P value
Protein (P) Material (M) M×P
2 5 10
6.60 68.03 7.19
.0036 <.0001 <.0001
Table IV. Result of Scheffé’s test (Scheffé grouping) Proteinaceous solution Material
Saliva
Albumin/PBS
Milk
Nov Mol Kur Eva Ast Exp
AB ABCD BCD CDE DE A
A ABCD ABCD BCD BCD A
AB BCD ABC CDE E A
Same letters indicate that the mean values shown in Table II are not significantly different.
1653 and 1540 cm–1, respectively. Means and standard deviations of absorbance at the amide I band are presented in Table II. The amount of adsorbed protein showed considerable variation among the 6 materials. It was always minimal for the experimental material (Exp) and maximum for acrylic resin (Ast) in 3 proteinaceous solutions. Ast adsorbed 2.7, 2.5, and 4.8 times more proteins than Exp in saliva, albumin/PBS, and milk, respectively. Results of the 2-way ANOVA revealed that 2 main factors and their interaction had significant effects on absorbance (Table III). Because of the significance of the interaction between the 2 main factors, direct comparison of the data within each factor was difficult. Figure 2 illustrates the effect of interaction between the 2 factors. Although the 2 line graphs for saliva and albumin are almost parallel, which indicates no interaction, the line for milk crosses the other lines, indicating interaction. This finding suggests that the interaction was mainly caused by the different adsorption behavior of milk onto polyolefin (Mol), fluoropolymer (Kur), and Ast. 349
THE JOURNAL OF PROSTHETIC DENTISTRY
IMAI AND TAMAKI
Fig. 2. Effects of proteins and materials on adsorption of protein expressed by adsorbance.
Fig. 1. IR spectra before (A) and after (B) adsorption of albumin on Mol. (C) shows results of spectral subtraction of (B) from (A).
Because of the interaction, 18 sets of data were subjected to 1-way ANOVA and post hoc Scheffé’s test. ANOVA resulted in significant differences (P<.0001). Table IV presents the result of the post hoc test. Adsorption of proteins to the Exp material and polyphosphazene (Nov) was significantly lower and was significantly higher for Ast and silicone (Eva). Mol exhibited high adsorption in milk but low adsorption in albumin/PBS. The protein adsorption on Kur was lower in milk than in saliva and albumin/PBS.
DISCUSSION The ATR/FT-IR technique has been a useful tool for investigating protein-material interactions.17 We applied this technique to measure protein adsorption onto 6 such materials in 3 proteinaceous solutions. In addition to saliva, albumin solution and milk were included in this study for comparative purposes because bovine albumin is a relatively pure protein that is easily available and milk is a popular drink that contains proteins. The amount of adsorbed protein demonstrated considerable variation among the 6 materials. Significantly lower adsorption of proteins in both the experimental material and polyphosphazene may be due to their unique composition or chemical structure. The former 350
was composed of a blend of a fluoropolymer and poly methacrylate/acrylate, which was formed by polymerization of the monomers during the curing process. The presence of the fluoropolymer is responsible for the low protein adsorption. In polyphosphazene, the phophazene structure itself is responsible for the low adsorption. Because of its special structure, polyphosphazene was included in this study, although Nov is not yet commercially available. The protein adsorption of Kur, a fluoropolymer, was significantly higher than that of the fluoropolymerbased experimental material. A possible explanation for this higher adsorption is that Kur is composed of a fluoromonomer, which is converted to fluoropolymer by polymerization. The resultant polymer does not appear to have characteristic properties of fluoropolymers. Only the oil-repellent property appears to be reflected in the relatively low protein adsorption in milk. Polyolefin material (Mol) exhibited higher adsorption of proteins in milk than in the other solutions. It is conceivable that the presence of lipids in the milk affected the protein adsorption because polyolefins usually have affinity to oily substances. Silicone (Eva) and acrylic resin (Ast) materials adsorbed more proteins, which may be correlated to the phenomena reported in the literature that more C albicans adheres to a silicone-based soft liner or acrylic resin-based tissue conditioner than to acrylic resin.5 Overall, the protein adsorption on the 6 materials in saliva and albumin/PBS was similar but it was different in milk (Fig. 2), although this conclusion may have limitations because of a single saliva source. This result leads to the following suggestions for evaluating protein adsorption: (1) albumin/PBS may be used as a model medium for saliva; and (2) different types of VOLUME 82 NUMBER 3
IMAI AND TAMAKI
medium such as milk containing lipids should be included to simulate an oral environment. The amount of adsorbed proteins varied considerably among the soft lining materials studied. The correlation between the amount of protein adsorption and C albicans adhesion should be investigated further. Nevertheless, less protein-adsorptive materials like fluoropolymers may be desirable for soft liners, because they absorb less water and oil, which results in less adhesion of dirt and microorganisms and, thus, fewer cases of colonization or development of bad odor.
CONCLUSION Within the limits of this study, the results demonstrated that the amount of proteins adsorbed onto the 6 materials studied was material-dependent. This finding suggests that C albicans adhesion could also be material-dependent. REFERENCES 1. Williamson JJ. The effect of denture lining materials on the growth of Candida albicans. Br Dent J 1968;125:106-10. 2. Allison RT, Douglas WH. Micro-colonization of the denture-fitting surface by Candida albicans. J Dent 1973;1:198-201. 3. Wright PS. The effect of soft lining materials on the growth Candida albicans. J Dent 1980;8:144-51. 4. Burns DR, Burns DA, DiPietro GJ, Gregory RL. Response of processed resilient denture liners to Candida albicans. J Prosthet Dent 1987;57:50711. 5. Okita N, Orstavik D, Orstavik J, Ostby K. In vivo and in vitro study on soft denture materials: microbial adhesion and tests for antibacterial activity. Dent Mater 1991;7:155-60. 6. Graham BS, Jones DW, Burke J, Thompson JP. In vivo fungal presence and growth on two resilient denture liners. J Prosthet Dent 1991;64:528-32. 7. Waters MG, Williams DW, Jagger RG, Lewis MA. Adherence of Candida albicans to experimental denture soft lining materials. J Prosthet Dent 1997;77:306-12.
SEPTEMBER 1999
THE JOURNAL OF PROSTHETIC DENTISTRY
8. Douglas WH, Walker DM. Nystatin in denture liners—an alternative treatment of denture stomatitis. Br Dent J 1973;135:55-9. 9. Davenport JC. The oral distribution of Candida in denture stomatitis. Br Dent J 1970;129:151-6. 10. Olsen I. Denture stomatitis: occurrence and distribution of fungi. Acta Odontol Scand 1974;32:329-33. 11. Makila E, Hopsu-Havu VK. Mycotic growth and soft denture lining materials. Acta Odontol Scand 1977;35:197-205. 12. Nikawa H, Iwanaga H, Kameda M, Hamada T. In vitro evaluation of Candida albicans adherence to soft denture-lining materials. J Prosthet Dent l992;68:804-8. 13. Nikawa H, Hamada T. Binding of salivary or serum proteins to Candida albicans in vitro. Arch Oral Biol 1990;35:571-3. 14. Samaranayake LP, McCourtie J, MacFarlane TW. Factors affecting the in vivo adherence of Candida albicans to acrylic surfaces. Arch Oral Biol 1980;25:611-5. 15. McCourtie J, MacFarlane TW, Samaranayake LP. Effect of saliva and serum on the adherence of Candida species to chlorhexidine-treated denture acrylic. J Med Microbiol 1986;21:209-13. 16. Nikawa H, Hyashi S, Nikawa Y, Hamada T, Samaranayake LP. Interaction between dentine lining material, protein pellicles and Candida albicans. Arch Oral Biol 1993;38:631-4. 17. Gendreau RM, Jakobsen RJ. Blood-surface interactions: Fourier transform infrared studies of protein adsorption from flowing blood plasma and serum. J Biomed Mater Res 1979;13:893-906.
Reprint requests to: DR YOHJI IMAI INSTITUTE FOR MEDICAL AND DENTAL ENGINEERING TOKYO MEDICAL AND DENTAL UNIVERSITY 2-3-10 KANDA-SURUGADAI TOKYO 101-0062 JAPAN FAX: 81-3-5280-8005 E-MAIL: [email protected] Copyright © 1999 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/99/$8.00 + 0. 10/1/98836
351