Factors involved in microbial colonization of oral prostheses
By J. Anthony Von Fraunhofer, MSc, PhD
Zwi Loewy, MS, PhD
Featured in General Dentistry, March/April 2009
Pg. 136-143
Posted on Friday, March 06, 2009
|
The presence of biofilm or denture plaque on the tissue contacting the (intaglio) surface of a denture is a major etiologic factor in the pathogenesis of both denture stomatitis and inflammatory papillary hyperplasia. This article reviews the literature concerning the various factors that contribute to the development of denture plaque and its colonization by Candida albicans and other microorganisms.
Received: June 23, 2008
Accepted: August 1, 2008
The adherence of microbial species to the surface of a denture, their subsequent proliferation, and the formation of denture plaque all affect oral and systemic health.1-3 This adherence of microorganisms contributes to mouth odor, denture stomatitis, and a variety of other complaints related to dentures. There is no clear evidence that a single contributory factor is responsible for the formation of denture plaque. It is likely that surface roughness provides an environment that promotes the initial attraction of early colonizers; however, biofilm formation depends on several factors, including the species of bacteria, the nature of the substrate, environmental factors, and key gene products.4
All dental professionals advocate regular and thorough sanitization of dentures to maintain oral health and eliminate mouth odor, based on evidence showing that the effective removal of denture plaque and preventing (or at least delaying) its formation helps to maintain denture cleanliness and promotes oral health.5,6
The contribution of Candida albicans (and other yeasts) to the etiology of denture stomatitis is well-recognized.5-15 Data indicate that denture biofilm formation is increased in areas affected by denture stomatitis; however, the cause of denture stomatitis is unclear.16 Although the prevalence of denture stomatitis is lower than the previous estimates of 65% (particularly among healthy subjects), the condition is strongly associated with C. albicans in most cases.17 This association appears to be particularly true with nocturnal denture wear, as there is a significant relationship between continuous denture wear and Candida spp.18 It should be noted that denture stomatitis also may be related to non-specific denture plaque.17
Respiratory pathogens have been reported to colonize dental plaques in the dependent elderly.1 In addition, inadequate cleaning of dentures allows for the multiplication of Candida spp. and bacteria.2 Methicillin-resistant Staphylococcus aureus and Streptococcus epidermis have been reported with C. albicans on denture surfaces.3 Adherence of S. aureus and C. albicans has been studied for resilient (soft) denture liners.19 These findings indicate the importance of microorganisms that adhere to denture materials (and their subsequent proliferation and colonization) in relation to oral and systemic health. This article addresses microbiological adherence to denture base materials and discusses the role of surface roughness, surface energy, and the characteristics of oral microbial species in this process.
Colonization of dentures by microorganisms
Microbiological colonization on the surfaces of removable oral appliances such as dentures results in the formation of deposits commonly referred to as denture plaque. This process involves numerous obligate, opportunistic, and pathogenic microorganisms; however, the mechanism involved is complex and not fully understood. The literature from the past 30-plus years clearly indicates the wide diversity of microorganisms detected on dentures and other removable dental appliances, as well as within the oral cavity of denture wearers (see Table 1).15,20-25 Many microbial species found on dentures can elicit substantial oral infections and induce systemic diseases; certain isolated bacteria (for example, members of the Entererobacteriaceae family, such as Klebsiella spp.) are thought to play a role in denture malodor.26 Unsurprisingly, edentulous patients who wear dentures have saliva with a bacterial composition similar to that found in denture plaque.27
Within 24 hours of exposure, microorganisms can substantially contaminate removable oral appliances.28 The posterior regions of dentures are more heavily contaminated than the anterior, while the interiors of most dentures generally experience more contamination than the surfaces.29 A 2007 study reported that mandibular dentures had a significantly higher biofilm percentage than their
Other studies have confirmed the presence of high levels of microorganisms (ca. 104–106/cm2) on the fitting (intaglio) denture surface and the palatal mucosa; the identified species included both aerobic and anaerobic bacteria.31 The predominant microflora on dentures appear to be Gram-positive bacteria (notably Streptococcus salivarius), although the proportions of cocci found in a control group and among those suffering from denture-induced stomatitis are different.32 It also should be noted that there is a strong similarity between microorganisms found on dentures and those on the pharyngeal mucosa; in addition, it has been suggested that denture plaque functions as a reservoir of potential respiratory pathogens that can colonize the pharynx.1,33 Other studies have suggested that denture plaque (as well as the appliances themselves) can function as reservoirs for mucosal infection.6,28,34,35
Chandra et al observed that, unlike cells grown in planktonic form, biofilm-associated C. albicans cells were resistant to antifungal agents used to treat denture stomatitis.6 This information indicates that the proliferation of microorganisms and their adherence to denture surfaces present a number of local (oral) and systemic problems for denture wearers. Clearly, controlling denture plaque is important for preventing local pathologic conditions such as denture stomatitis, as well as serious systemic conditions such as aspiration pneumonia.
Factors in dental biofilm formation
It may be intuitively obvious that the surface roughness of a denture will affect sequential development of denture plaque and its colonization by C. albicans and other microorganisms. Based on the observation that the posterior regions of dentures are more heavily contaminated than the anterior and that the interiors of most dentures generally are more contaminated than the surfaces, a number of other factors may be involved.30 Although porosity within dentures is the result of a number of factors and tends to vary, it is possible that the microporosity of denture base material (Fig. 1) may play a major role in this phenomenon.14,36
Although it is recognized that the adherence of microorganisms to a denture surface is a prerequisite for colonization (Fig. 2), surprisingly few studies have involved surface roughness and how it affects the retention of organisms. Indeed, other than measuring the average surface roughness, limited attention has been paid to the properties and character of the denture surface as it affects microbial adhesion.17 Candida biofilms show a propensity to adhere to cracks and imperfections in the denture acrylic.5 It has been suggested that the adherence of C. albicans to denture-base materials in vitro is related to the hydrophobicity of the organism.5,37 Other studies suggest that factors other than hydrophobic interactions play an important role in the adherence of C. albicans, particularly when pellicle-coated soft liners and tissue conditioners are involved.1 This is supported by Nevzatoglu et al, who employed a variety of surface finishes and reported that C. albicans’ adherence to denture base acrylics was significantly less than its adherence to silicone liners.38
Nevertheless, studies show that surface roughness affects the accumulation of plaque and its subsequent colonization, and there is evidence that the surface roughness of acrylic (polymethylmethacrylate, or PMMA) resin affects the early stages of biofilm formation (at least when Streptococcus oralis is involved).39 A 2001 study by Morgan and Wilson examined heat-cured and cold-cured acrylic and noted that the number of bacteria adhering to either acrylic increased linearly with mean surface roughness after a two-hour incubation period. The increase in bacterial adhesion was greater for a cold-cured acrylic resin than for the harder (more abrasion-resistant) heat-cured acrylic resin following surface abrasion with abrasive paper; however, surface roughness had no effect on the number of adherent bacteria after four hours. It was concluded that smooth acrylic surfaces could lead to reduced biofilm formation in vivo.39 Other studies have shown that rough surfaces promote the adhesion of C. albicans and other microorganisms to denture base materials in vitro.40-42
Unpublished data from one of the authors (JAvF) indicates that using a dental lathe to polish denture base acrylic resin with aqueous slurries of medium, fine, and very fine polishing abrasives (pumice) (as well as flour of pumice) produces very smooth surfaces (see Table 2). A 2005 study reported that conventional laboratory polishing of acrylic resin produced the smoothest acrylic surface finish, with a threshold mean arithmetic surface roughness (Ra) of 0.02 (± 0.01) µm, while surfaces finished with a tungsten carbide bur were the roughest (Ra = 2.86–3.99 µm).43 Other studies reported similar observations when the surface finish of acrylic resin and denture resilient liners were evaluated.44 Zissis et al reported that denture base (PMMA) materials had Ra values of 3.4–7.6 µm, while hard liners had Ra values of 0.7–4.4 µm.45 The surfaces of autopolymerized and visible photocured soft liners had Ra values of 0.7–3.5 µm, while the heat-cured soft liners had Ra values of 3.5–4.0 µm.45
The Ra value for bacterial adherence is considered to be 0.2 µm, although the surface roughness for denture base materials can be markedly higher than this threshold value, depending on the surface finish and subsequent exposure conditions.45 These roughness values (primarily Ra > 0.7 µm) clearly indicate the possibility for plaque accumulation on all tested materials.
Morgan and Wilson showed that both surface finish and the type of microorganism affected adhesion to denture base materials.39 The number of bacteria adhering to heat-cured and cold-cured acrylic increased linearly with mean surface roughness. Among all microorganisms tested, Streptococcus sanguis and Porphyromonas gingivalis were found to have the most adherence to denture base resin.39 Streptococcus sanguis was less adherent to the smoothed surface than Streptococcus mitis or C. albicans, while no relationship between surface texture and bacterial adherence was observed for the other microorganisms tested.40 This finding appears to contradict studies indicating that C. albicans had greater retention on rough surfaces.41,42 Nevertheless, the authors noted less loss of C. albicans from the abraded surface than from the polished surface, indicating overall that smoothing the denture base surface is important for denture plaque control.40 In particular, one study comparing C. albicans retention on PMMA and silicone resilient liner surfaces showed no differences in retention on the smooth surfaces after incubation for one hour at 24°C.41 However, significantly higher numbers of cells were found on roughened surfaces and C. albicans retention was greater on the more hydrophobic silicone liner surface than on acrylic resin surfaces.41
A 2000 study regarding bacterial adherence and surface roughness examined four different types of acrylic resin denture base material and indicated that not only did all four types have similar numbers of adhering bacteria but also that polishing had little effect on adherence.46 Six years later, Bregula et al suggested that C. albicans adherence differed for different denture base materials and that polishing reduced microbial adherence.47
These conflicting studies raise an interesting question: What are the short- and long-term effects of abrasive dentifrices on dentures’ susceptibility to plaque formation? It has been reported that brushing is more effective than immersion cleansers for biofilm removal and that the best sanitization is achieved with brushing and immersion cleansing.48 However, the data suggest that using a toothbrush and an abrasive dentifrice to clean dentures is contraindicated.8,14
The literature suggests that other factors also may contribute to the adherence of microorganisms to denture surfaces. The materials selected and the method used to process the denture certainly will affect surface free energy. It has been reported that the method of curing and the substrate itself both affect the adherence of microbes; this appears to be particularly true for resilient denture liner materials.7,52,53 Conversely, other studies suggest that neither the polymerization method nor the denture base acrylic resin affect the adherence of Candida spp.38,54
According to Moura et al, saliva will decrease overall yeast adherence.55 Other studies have reached the same conclusion and reported that saliva reduces the adhesion of C. albicans and thus diminishes the microbiotic adherence of surface roughness and free surface energy differences between materials.41,56 While the hydrophobicity of the microorganism, hydrophobic interactions, surface roughness, and surface free energy may be involved in microorganisms adhering to surfaces and biofilm formation, they certainly are not the only determining factors in surface retention.3,17,37
While Candida species adhering to the surfaces of prostheses is essential for the pathogenesis of denture stomatitis, there appear to be other factors that promote the initial adherence.
Preventing biofilm formation
Biofilm formation is a prominent feature of bacterial growth and biofilms are known to form fairly readily. In fact, biofilms are thought to be a predominant mode of microbial growth in nature, as they are involved in a wide variety of different processes.57 It is well-established that microorganisms in their natural environments attach to surfaces and that biofilm formation is initiated by microbial adhesion to a surface.58 As microbial colonization continues, the growth of adherent micro-organisms causes the formation of microbial clusters or microcolonies. As growth continues, the substrate surface is covered by a community of microcolonies commonly known as a biofilm.59 The cells within the constituent microcolonies of biofilms tend to aggregate and are surrounded by water channels, which contain few cells.57
Although the physiology of biofilms is poorly understood, it has been suggested that the high cell density and limited access to nutrients indicates quorum-sensing gene activity.57 In addition, the high cell density within biofilms and their constituent microcolonies may indicate that cell-to-cell interactions are occurring. This characteristic may account for the difficulty encountered in eliminating biofilm, as well as its high resistance to antimicrobial agents, disinfectants, and antibiotics.
While there appear to have been no studies on the architecture of denture plaque, a 2006 study by Robinson et al examined the architecture of natural human plaque biofilm.60 It has been shown that the outer regions of microbial biofilms strongly influence the interaction between the biofilm and its local environment, particularly the flux of materials into and out of biofilm compartments.60 As a result, the outer regions of the biofilm influence its overall metabolic behavior.
With dental plaque biofilms formed on teeth, the biofilm architecture determines access of both nutrients and therapeutic materials to the microbial biomass and the substrate tooth surface. Robinson et al reported that the amount and density of the biomass in biofilm increased from the plaque/saliva interface toward the interior.60 Mechanical manipulation, high ionic strength, and low pH (2.5) have little effect on biofilms, a finding that echoes earlier studies.57 However, detergents such as sodium lauryl sulfate (SLS) appear capable of removing the biomass and/or reducing its density dramatically.60
Clearly, prevention is better than cure and the literature offers some suggestions on how to reduce dentures’ susceptibility to biofilm formation. Uyen et al suggested that negatively charged denture base materials have greater resistance to streptococcal adhesion.61 The authors’ 1989 study found that the zeta potentials of both various bacterial strains and PMMA restorations were reduced by increasing the ionic strength of the buffer suspension, which in turn increased the number of adhering Streptococcus bacteria (mitis, sanguis, and mutans).61 Since streptococcal adherence is considered to be a prerequisite for the subsequent adhesion of C. albicans to a denture surface, changing the surface charge may prevent (or at least reduce) streptococcal adhesion. This change may reduce subsequent adhesion of Candidae and could reduce the occurrence of denture-induced stomatitis. These effects of ionic media may account for the reported inhibitive effect of saliva and serum films on the adhesion of C. albicans.
Other studies have investigated the possibility of changing the resin surface charge by replacing the customary methyl methacrylate monomer of a denture base resin with one containing phosphate.62 This approach induces an anionic charge on denture base resin. While no microbiological data are available yet, using the phosphate-based monomer to replace 10% of the conventional monomer was shown to cause some reduction in physical properties; however, the resin’s strength and other properties remained within the requirements of ADA specifications.62 Based on these results, it is conceivable that modifying the composition of denture base materials could help to prevent denture plaque formation.
Wilson and Harvey described using surface modifications as a way of preventing bacterial adhesion in a 1989 study that evaluated the ability of a variety of non-toxic polysaccharides to prevent in vitro bacterial adhesion to denture base acrylic resin.63 The findings indicated that sodium alginate, karaya gum, and carrageenan were the most effective in reducing adhesion of Streptococcus salivarius by 98.7%, 97.9%, and 99.2%, respectively. Sodium alginate was found to be the most effective at reducing the number of bacteria adhering to dentures in vivo. After five hours of wear, sodium alginate reduced bacterial attachment to the palate-contacting surface of the denture by 84% when compared with uncoated controls.63 These findings suggest that denture plaque accumulation may be reduced and possibly prevented by frequent application of a renewable coating of non-toxic polysaccharide. At the least, there is evidence that applying surface coatings significantly reduces early biofilm formation on dental restorations.64
Dental care providers should strongly encourage patients to ensure that their dentures are free from microbial contamination (typically biofilms and yeasts), not only for odor control but to maintain and possibly improve oral and systemic health. However, until consumer-applied renewable surface coatings become commercially available and denture base resins with an altered surface charge are available to the profession through dental laboratories, denture patients face the challenge of satisfactory denture sanitization. Based on the available evidence (and clinical experience), effervescent cleansers still offer the safest and most satisfactory approach to biofilm removal and odor control for denture wearers.
Summary
It is clear that plaque on the tissue-contacting (intaglio) surface of the denture is a major etiologic factor in the pathogenesis of denture stomatitis, inflammatory papillary hyperplasia, and chronic candidiasis. These microporous surfaces provide support for a variety of microorganisms that may threaten the oral health of all patients and the systemic health of physically vulnerable patients. Although the mechanism involved in the formation of biofilm is uncertain, it is clear that sanitization of oral prostheses through removal of denture plaque is important for patient health and to maintain an esthetic, odor-free appliance.
The literature indicates that surface roughness is a contributory factor to the development of denture plaque and its colonization by C. albicans and other microorganisms. The evidence also suggests that the hydrophobicity of C. albicans (and possibly that of other microorganisms) may contribute to microbiological adhesion on surfaces, although other factors also may be involved. Based on this evidence, it is clear that non-abrasive cleansers, such as effervescent cleansers and possibly abrasive-free dentifrices, are the materials of choice for cleaning dentures.
Acknowledgements
The authors wish to thank Paul Grech for assistance with the illustrations used in this article and Drs. Brendan Marken and Andrew Middleton for helpful comments and critical reading of the manuscript.
Disclaimer
Dr. von Fraunhofer has no commercial or proprietary interest in any of the products mentioned in this article. Dr. Loewy is an employee of GlaxoSmithKline, a manufacturer of some of the products mentioned in this article, and has no affiliation with any other products.
Author information
Dr. von Fraunhofer is Professor Emeritus at the
References
1. Sumi Y, Miura H, Michiwaki Y, Nagaosa S, Nagaya M. Colonization of dental plaque by respiratory pathogens in dependent elderly. Arch Gerontol Geriatr 2007;44(2):119-124.
2. Gornitsky M, ParadisI I, Landaverde G, Malo AM, Velly AM. A clinical and microbiological evaluation of denture cleansers for geriatric patients in long-term care institutions. J Can Dent Assoc 2002;68(1):39-45.
3. Tawara Y, Honma K, Naito Y. Methicillin-resistant Staphylococcus aureus and Candida albicans on denture surfaces. Bull
4. Rodriguez-Martinez JM, Pascual A. Antimicrobial resistance in bacterial biofilms. Rev Med Microbiol 2006;17:65-75.
5. Abelson DC. Denture plaque and denture cleansers. J Prosthet Dent 1981;45(4):376-379.
6. Shay K. Denture hygiene: A review and update. J Contemp Dent Pract 2000;1(2):28-41.
7. Ramage G, Tomsett K, Wickes BL, Lopez-Ribot JL, Redding SW. Denture stomatitis: A role for Candida biofilms. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98(1):53-59.
8. Chandra J, Mukherjee PK, Leidich SD, Faddoul FF, Hoyer LL, Douglas LJ, Ghannoum MA. Antifungal resistance of candidal biofilms formed on denture acrylic in vitro. J Dent Res 2001;80(3):903-908.
9. He XY, Meurman JH, Kari K, Rautemaa R, Samaranayake LP. In vitro adhesion of Candida species to denture base materials. Mycoses 2006;49(2):80-84.
10. Kanli A, Demirel F, Sezgin Y. Oral candidosis, denture cleanliness and hygiene habits in an elderly population. Aging Clin Exp Res 2005;17 (6):502-507.
11. Budtz-Jorgensen E, Bertram U. Denture stomatitis. I. The etiology in relation to trauma and infection. Acta Odontol Scand 1970;28(1):71-92.
12.
13. van Reenen JF. Microbiologic studies on denture stomatitis. J Prosthet Dent 1973;30(4):493-505.
14. Allison RT, Douglas WH. Micro-colonization of the denture-fitting surface by Candida albicans. J Dent 1973;1(5):198-201.
15. Koopmans AS, Kippuw N, de Graaff J. Bacterial involvement in denture-induced stomatitis. J Dent Res 1988;67(9):1246-1250.
16. Avon SL, Goulet JP, Deslauriers N. Removable acrylic resin disk as a sampling system for the study of denture biofilms in vivo. J Prosthet Dent 2007;97(1):32-38.
18. Compagnoni MA, Souza RF, Marra J, Pero AC, Barbosa DB. Relationship between Candida and nocturnal denture wear: Quantitative study. J Oral Rehabil 2007;34(8):600-605.
19. Cal E, Kesercioglu A, Sen BH, Cilli F. Comparison of the hardness and microbiologic adherence of four permanent denture soft liners. Gen Dent 2006;54(1):28-32.
20. Catalan A, Herrera R, Martinez A. Denture plaque and palatal mucosa in denture stomatitis: Scanning electron microscopic and micro-biologic study. J Prosthet Dent 1987;57(5): 581-586.
21. Gusberti FA, Gada TG, Lang NP, Geering AH. Cultivable microflora of plaque from full denture bases and adjacent palatal mucosa. J Biol Buccale 1985;13(3):227-236.
22. Theilade E, Budtz-Jorgensen E, Theilade J. Predominant cultivable microflora of plaque on removable dentures in patients with healthy oral mucosa. Arch Oral Biol 1983;28(8):675-680.
23. Ghamrawy EE. Qualitative changes in dental plaque formation related to removable partial dentures. J Oral Rehabil 1979;6(2):183-188.
24. Glass RT, Bullard JW, Hadley CS, Mix EW, Conrad RS. Partial spectrum of microorganisms found in dentures and possible disease implications. J Am Osteopath Assoc 2001;101(2):92-94.
25.
26. Goldberg S, Cardash H, Browning H 3rd, Sahly H, Rosenberg M. Isolation of Entererobacteriaceae from the mouth and potential association with malodor. J Dent Res 1997;76(11):1770-1775.
27. Sato M, Hoshino E, Nomura S, Ishioka K. Salivary microflora of geriatric edentulous persons wearing dentures. Microbial Ecology Health Dis 1993;6:293-299.
28. Glass RT, Bullard JW, Conrad RS. The contamination of protective mouthguards. Amer Inst Contin Educ 2006;93:23-36.
29. Glass RT, Belobraydic K. The dilemma of denture contamination. J
30. Salles AE, Macedo LD, Fernandes RA, Silva-Lovato CH, Paranhos Hde F. Comparative analysis of biofilm levels in complete upper and lower dentures after brushing associated with specific denture paste and neutral soap. Gerodontology 2007;24(4):217-223.
31. Monsenego P. Presence of microorganisms on the complete denture fitting surface: Study ‘in vivo’. J Oral Rehabil 2000;27(8):708-713.
32.
33. Sumi Y, Kagami H, Ohtsuka Y, Kakinoki Y, Haruguchi Y, Miyamoto H. High correlation between the bacterial species in denture plaque and pharyngeal microflora. Gerodontology 2003;20(2):84-87.
34. Glass RT. Other factors in infections: The transmission of disease. Gerodontics 1986;2(4):119-120.
35. Glass RT. Transmission of disease: The role of the toothbrush and the denture. Amer Acad Oral Path Abstracts 1990;63(April 25).
36. Powers JM, Sakaguchi RL. Craig’s restorative dental materials, ed. 12.
37. Nikawa H, Iwanaga H, Kameda M, Hamada T. In vitro evaluation of Candida albicans adherence to soft denture-lining materials. J Prosthet Dent 1992;68(5):804-808.
38. Nevzatoglu EU, Ozcan M, Kulak-Ozkan Y, Kadir T. Adherence of Candida albicans to denture base acrylics and silicone-based resilient liner materials with different surface finishes. Clin Oral Investig 2007;11(3):231-236.
39. Morgan TD, Wilson M. The effects of surface roughness and type of denture acrylic on biofilm formation by Streptococcus oralis in a constant depth film fermentor. J Appl Microbiol 2001;91 (1):47-53.
40. Yamauchi M, Yamamoto K, Wakabayashi M, Kawano J. In vitro adherence of microorganisms to denture base resin with different surface texture. Dent Mater J 1990;9(1):19-24.
42. Verran J, Maryan CJ. Retention of Candida albicans on acrylic resin and silicone of different surface topography. J Prosthet Dent 1997;77(5):535-539.
43. Kuhar M, Funduk N. Effects of polishing techniques on the surface roughness of acrylic denture base resins. J Prosthet Dent 2005;93(1):76-85.
45. Zissis AJ, Polyzois GL, Yannikakis SA, Harrison A. Roughness of denture materials: A comparative study. Int J Prosthodont 2000;13(2):136-140.
46. Kagermeier-Callaway AS, Willershausen B, Frank T, Stender E. In vitro colonisation of acrylic resin denture base materials by Streptococcus oralis and Actinomyces viscosus. Int Dent J 2000;50 (2):79-85.
47. Breguła L, Trzeciak H,
selected acrylic resins] [article in Polish]. Med Dosw Mikrobiol 2006;58(1):67-71.
48. Paranhos HF, Silva-Lovato CH, Souza RF, Cruz PC, Freitas KM, Peracini A. Effects of mechanical and chemical methods on denture biofilm accumulation. J Oral Rehabil 2007;34(8):606-612.
49. Wetterer S, Chu G, Loewy Z. Persistence of scratching induced by toothpaste brushing of denture acrylic. Abstract presented at the 37th annual meeting of the AADR; April 2008:
50. West P, Charman K, Fernandez P, Ignar R, Kleber C, Loewy Z, Ioannou C, Middleton A. Impact of toothpaste brushing of denture material on bacterial attachment. Abstract presented at the 37th annual meeting of the AADR; April 2008:
51. Goldsmith RN, Shey Z, Houpt MI, Fine D, Schreiner H, Greenberg B. Toothbrush bristle wear and adherence of Streptococcus mutans. Pediatr Dent 2007;29(3):243-247.
52. Tari BF, Nalbant D, Dogruman Al F, Kustimur S. Surface roughness and adherence of Candida albicans on soft lining materials as influenced by accelerated aging. J Contemp Dent Pract 2007;8(5):18-25.
53. Bulad K, Taylor RL, Verran J, McCord JF. Colonization and penetration of denture soft lining materials by Candida albicans. Dent Mater 2004;20(2): 167-7553.
54. Serrano-Granger C, Cerero-Lapiedra R, Campo-Trapero J, Del Río-Highsmith J. In vitro study of the adherence of Candida albicans to acrylic resins: Relationship to surface energy. Int J Prosthodont 2005;18(5):392-398.
55. Moura JS, da Silva WJ, Pereira T, Del Bel Cury AA, Rodrigues Garcia RC. Influence of acrylic resin polymerization methods and saliva on the adherence of four Candida species. J Prosthet Dent 2006;96(3):205-211.
56. Pereira-Cenci T, Cury AA, Cenci MS, Rodrigues-Garcia RC. In vitro Candida colonization on acrylic resins and denture liners: Influence of surface free energy, roughness, saliva, and adhering bacteria. Int J Prosthodont 2007;20(3): 308-310.
57. McLean RJC, Fuqua C, Siegele DA, Kirkland BL, Adams JL, Whiteley M. Biofilm growth and illustrations of its role in mineral formation. In:
58. Marshall KC, Stout R, Mitchell R. Mechanisms of the initial events in the sorption of marine bacteria to solid surfaces. J Gen Microbiol 1971;68: 337-348.
59. Costerton JW, Lewandowski Z,
60. Robinson C, Strafford S, Rees G, Brookes SJ, Kirkham J, Shore RC, Watson PS, Wood S. Plaque biofilms: The effect of chemical environment on natural human plaque biofilm architecture. Arch Oral Biol 2006;51(11):1006-1014.
61. Uyen HM, van der Mei HC, Weerkamp AH, Busscher HJ. Zeta potential and the adhesion of oral streptococci to polymethylmethacrylate. Biomater Artif Cells Artif Organs 1989;17(4):385-391.
62. Dhir G, Berzins DW, Dhuru VB,
63. Wilson M,
64.
|
General Dentistry, March/April 2009 , Volume 57 , Issue 2
|
|
||||||||||||
