Jackson Sarah, Coulthwaite Lisa, Loewy Zvi, Scallan Anthony, Verran Joanna
Postgraduate student, School of Health Care Science, Manchester Metropolitan University, Manchester, United Kingdom.
Senior Lecturer, School of Health Care Science, Manchester Metropolitan University, Manchester, United Kingdom.
J Prosthet Dent. 2014 Oct;112(4):988-93. doi: 10.1016/j.prosdent.2014.02.003. Epub 2014 Apr 14.
Candida albicans is a known etiologic agent of denture stomatitis. Candida hyphae exhibit the ability to respond directionally to environmental stimuli. This characteristic is thought to be important in the penetration of substrata such as resilient denture liners and host epithelium. It has been suggested that hyphal production also enhances adhesion and survival of Candida on host and denture surfaces. Surface roughness, in addition, can enhance adhesion where stronger interactions occur between cells and surface features of similar dimensions.
The purpose of this study was to assess the development of hyphal and blastospore biofilms on abraded denture acrylic resin specimens and measure the ease of removal of these biofilms.
Biofilms were grown for 48 hours on abraded 1-cm² denture acrylic resin specimens from adhered hyphal phase C albicans or from adhered blastospores. Subsequently, all specimens were stained with Calcofluor White and examined with confocal scanning laser microscopy. Biofilms were removed by vortex mixing in sterile phosphate buffered saline solution. Removed cells were filtered (0.2-μm pore size). Filters were dried at 37°C for 24 hours for dry weight measurements. Any cells that remained on the acrylic resin specimens were stained with 0.03% acridine orange and examined with epifluorescence microscopy.
Biofilms grown from both cell types contained all morphologic forms of C albicans. Although the underlying surface topography did not affect the amount of biofilm produced, biofilms grown from hyphal phase Candida were visibly thicker and had greater biomass (P<.05). These biofilms were less easily removed from the denture acrylic resin, especially in the case of rougher surfaces, evidenced by the higher numbers of retained cells (P≤.05).
The presence of hyphae in early Candida biofilms increased biofilm mass and resistance to removal. Increased surface roughness enhances retention of hyphae and yeast cells, and, therefore, will facilitate plaque regrowth. Therefore, minimization of denture abrasion during cleaning is desirable.
白色念珠菌是义齿性口炎的一种已知病原体。白色念珠菌菌丝表现出对环境刺激作出定向反应的能力。这一特性被认为在穿透诸如弹性义齿衬垫和宿主上皮等基质方面很重要。有人提出，菌丝的产生还可增强念珠菌在宿主和义齿表面的黏附及存活。此外，表面粗糙度可增强黏附，因为在细胞与尺寸相似的表面特征之间会发生更强的相互作用。
本研究的目的是评估在磨损的义齿丙烯酸树脂标本上菌丝和芽生孢子生物膜的形成，并测量这些生物膜的去除难易程度。
生物膜在来自黏附的白色念珠菌菌丝相或黏附的芽生孢子的磨损1平方厘米义齿丙烯酸树脂标本上生长48小时。随后，所有标本用荧光增白剂染色，并用共聚焦扫描激光显微镜检查。通过在无菌磷酸盐缓冲盐溶液中涡旋混合去除生物膜。去除的细胞经过过滤（孔径0.2微米）。滤膜在37°C干燥24小时以进行干重测量。留在丙烯酸树脂标本上的任何细胞用0.03%吖啶橙染色，并用落射荧光显微镜检查。
两种细胞类型形成的生物膜均包含白色念珠菌的所有形态形式。尽管底层表面形貌不影响生物膜的产生量，但由念珠菌菌丝相形成的生物膜明显更厚且生物量更大（P<0.05）。这些生物膜更难从义齿丙烯酸树脂上去除，尤其是在表面更粗糙的情况下，留存细胞数量更多证明了这一点（P≤0.05）。
早期念珠菌生物膜中菌丝的存在增加了生物膜质量和去除抗性。表面粗糙度增加会增强菌丝和酵母细胞的留存，因此会促进菌斑再生长。因此，清洁过程中尽量减少义齿磨损是可取的。
