Title 3D-Printed Denture Bases Have Increased Adherence of Candida albicans when Compared to Conventional and Milled Bases In Vitro
Clinical Question For patients receiving a complete denture, do the surface properties of 3D-printed denture bases facilitate colonization by Candida albicans when compared to conventional PMMA denture bases?
Clinical Bottom Line For patients receiving a complete denture, 3D-printed denture bases’ surface properties do facilitate colonization by C. albicans at levels greater than conventional and milled denture bases. This is supported by multiple in vitro laboratory tests in which printed bases demonstrated significantly greater levels of C. albicans adhesion. In vitro studies show that the employment of 3D-printed manufacturing methods increases C. albicans surface adherence (a known etiologic factor for contraction of denture stomatitis) and may therefore necessitate more thorough denture and oral hygiene methods compared to conventionally heat-packed or milled denture bases. Clinical studies are needed to confirm whether this increase in C. albicans adhesion increases the risk of denture stomatitis.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
37111983Osman / 202314 samples/materialLaboratory study
Key resultsAfter 24 hours, quantification of fungal adhesion using XXT assay found that 3D-printed denture bases exhibited significantly greater colonization by C. albicans (2.2 ± 0.19 relative absorbance) than conventional heat-cured bases (0.98 ± 0.14, relative absorbance), which were in turn higher than milled bases (0.48 ± 0.14 relative absorbance) in vitro at a p < 0.001 level. One limitation of the study was that the authors did not correlate material properties, like surface roughness or contact angle measurements, to degree of adhesion.
35941701Koujan / 202310 samples/materialLaboratory study
Key resultsAfter 16 hours, milled (1.0356 ± 0.1493 OD 600) and heat-cured PMMA resins (0.0037 ± 0.0004 OD 600) had significantly lower level of adherence of C. albicans than 3D-printed denture bases (1.7938 ± 0.1277 OD 600) in vitro at a p < 0.05 level. This study also has the same limitations in that material properties and the monomers used were not considered or correlated with adhesion.
35661475Freitas / 202325 samples/materialLaboratory study
Key results3D-printed materials had significantly greater surface roughness and lower contact angles (Ra=0.317±0.151 µm and CA=70.82˚±2.95˚, p<0.05) than the CAD-CAM, microwave and heat cured resin groups (Ra range 0.175 – 0.201 µm and CA range 77.52˚-82.28˚). However, none of these factors correlated with the degree of C. albicans adhesion. After 16 hours, milled denture bases had significantly lower C. albicans adhesion (3.74 ± 0.57 mean Log CFU/mL) [p<0.001] than all other groups (3D-printed denture bases = 5.77 ± 0.36 mean Log CFU/mL; conventional heat-cured bases = 5.12 ± 1.01 mean Log CFU/mL; microwave polymerized bases = 5.23 ± 0.48 mean Log CFU/mL).
37111983Meirowitz / 20216 samples/materialLaboratory study
Key resultsCold-cured resins had significantly higher surface roughness and contact angles than milled, 3D-printed and heat-cured resins (p<0.03 and p<0.001, respectively). 3D-printed resins had significantly higher mucin adsorption than all other groups (p<0.001). After incubation for 4 hours, C. albicans adhesion correlated somewhat with mucin adhesion results. Milled resins had significantly lower C. albicans adhesion than all other groups (p<0.001), and 3D-printed and cold-cured resins had significantly higher adhesion than heat-cured and milled resins (p<0.001). Only mucin adsorption seems to have some correlation to C. albicans adhesion.
Evidence Search ((3d[all fields]) OR(3-d[all fields]) OR (printed[all fields]) OR (cad[all fields]) OR (CAD/CAM[all fields]) OR ("computer aided design"[MeSH Terms]) OR ("computer aided"[All Fields]) OR ("computer aided design"[All Fields]) OR ("cad"[All Fields]) OR ("cam"[All Fields]) OR ("cad cam"[All Fields])) AND ((denture[all fields]) OR (PMMA[all fields]) OR (polymethyl[all fields]) OR (methacrylate[all fields]) OR (acrylic[all fields]) OR (resin[tiab]) OR (dental[tiab]) OR (dentistry[tiab]) OR (dentistry[Mesh terms]) OR (prosthodontic[all fields]) OR (prosthodontics[all fields]) OR (prosthodontic[Mesh terms])) AND ((candida[all fields]) OR (candida[Mesh terms]) OR (candidal[all fields]) OR (fungal[tiab]) OR (fungus[tiab]) OR (fungi[tiab]) OR (fungi[Mesh terms]) OR (albicans[all fields])) NOT (covid[all fields])
Comments on
The Evidence
While variation in testing methods often makes reconciliation of results challenging, this literature review finds that regardless of employed 3D-printing methods/parameters and experimental design, additively manufactured denture bases are more prone to Candida adhesion than heat-cured, and especially milled denture bases. However, the hypothesis that increased surface roughness is responsible for increased C. albicans adhesion is not substantiated by these studies. Some standardization of experimental design would benefit this field of study, as only two of the articles listed layer thickness (Osman and Freitas), and only Osman listed build angle, a factor that has been shown to influence candida adhesion. Furthermore, no two articles used the same brand of 3D printable resin or 3D printer, and selection of the other material brands also varied. This inconsistency may account for the outlying finding by Freitas et al. that there is no significant difference in candida adherence between 3D-printed denture bases and conventional bases. Another variation in method is by Osman et al. who designed the specimens to be unpolished sections of a maxillary denture base, as would be found in vivo, rather than polished pucks as all other articles did. This model is much more realistic, and its use should be considered for studies such as these. Meirowitz et al. did not publish numeric data for the microbial cell counts but displayed all results in graphical form. The studies reviewed were all in vitro, and in vivo studies are needed to further evaluate the multifactorial nature of Candida adherence on denture bases made with various fabrication techniques, and to determine if these differences are clinically significant.
Applicability Because of the greater risk of Candida albicans colonization and the possible subsequent increase in the risk of denture stomatitis, use of 3D-printed denture bases may necessitate a stronger emphasis on oral and denture hygiene instructions and monitoring of patient compliance and early signs of denture stomatitis.
Specialty (General Dentistry) (Prosthodontics) (Restorative Dentistry)
Keywords Candida albicans, denture stomatitis, CAD/CAM, 3-D print, additive manufacturing, PMMA, acrylic, denture, prosthodontics, dentistry
ID# 3539
Date of submission 10/19/2023
E-mail nguond@uthscsa.edu
Author Destin Nguon
Co-author(s) Mustafa Girnary
Co-author(s) e-mail girnary@uthscsa.edu
Faculty mentor Kyumin Whang, PhD
Faculty mentor e-mail Whang@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available