Graduate student, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia; Lecturer, Department of Conservative Dentistry & Prosthodontics, Faculty of Dentistry, Universiti Sains Islam Malaysia, Negeri Sembilan, Malaysia.
Associate Professor, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.
J Prosthet Dent. 2023 Jul;130(1):131.e1-131.e7. doi: 10.1016/j.prosdent.2023.04.017. Epub 2023 May 19.
How the build orientation of a 3-dimensionally (3D) printed denture affects microbial adhesion is unclear.
The purpose of this in vitro study was to compare the adherence of Streptococcus spp. and Candida spp. on 3D-printed denture bases prepared at different build orientations with conventional heat-polymerized resin.
Resin specimens (n=5) with standardized 28.3 mm surface area were 3D printed at 0 and 60 degrees, and heat-polymerized (3DP-0, 3DP-60, and HP, respectively). The specimens were placed in a Nordini artificial mouth (NAM) model and exposed to 2 mL of clarified whole saliva to create a pellicle-coated substratum. Suspensions of Streptococcus mitis and Streptococcus sanguinis, Candida albicans and Candida glabrata, and a mixed species, each at 10 cfu/mL were pumped separately into the model for 24 hours to promote microbial adhesion. The resin specimens were then removed, placed in fresh media, and sonicated to dislodge attached microbes. Each suspension (100 μL) was aliquoted and spread on agar plates for colony counting. The resin specimens were also examined under a scanning electron microscope. The interaction between types of specimen and groups of microbes was examined with 2-way ANOVA and then further analysis with Tukey honest significant test and Kruskal-Wallis post hoc tests (α=.05).
A significant interaction was observed between the 3DP-0, 3DP-60, and HP specimen types and the groups of microbes adhering to the corresponding denture resin specimens (P<.05). The difference was statistically significant among 3DP-0, 3DP-60, and HP specimens (P<.05). The adherence of candida was 3.98-times lower on the 3DP-0 than that of HP (P<.05). However, adherence of the mixed-species microbes and streptococci on the 3DP-60 were 1.75 times and 2-fold higher, respectively (P<.05). The scanning electron micrographs showed that 3DP-0 exhibited the lowest microbial adherence compared with HP and 3DP-60.
Adherence affinity of denture base resin is affected by the build orientation rather than by the group of different microbes. Three-dimensionally printed denture base resin fabricated at a 0-degree build orientation exhibited low affinity for microbial adhesion. Three-dimensionally printed dentures may reduce microbial adhesion when printed at a 0-degree build orientation.
三维（3D）打印义齿的构建方向如何影响微生物黏附尚不清楚。
本体外研究的目的是比较不同构建方向的 3D 打印义齿基底与传统热聚合树脂对链球菌属和念珠菌属黏附的影响。
用标准化的 28.3mm 表面积制作树脂样本（n=5），在 0 度和 60 度方向进行 3D 打印，分别标记为 3DP-0、3DP-60 和 HP。将标本放置在 Nordini 人工口腔（NAM）模型中，暴露于 2ml 澄清全唾液中，以形成包被有黏膜的基质。将浓度为 10 cfu/mL 的米氏链球菌和血链球菌、白念珠菌和光滑念珠菌以及混合物种的悬浮液分别泵入模型中 24 小时，以促进微生物黏附。然后将树脂标本取出，放入新鲜培养基中，超声以去除附着的微生物。将每个悬浮液（100μL）等分并涂抹在琼脂平板上进行菌落计数。用扫描电子显微镜检查树脂标本。用双向方差分析检验标本类型和黏附微生物组之间的相互作用，然后用 Tukey 诚实显著检验和 Kruskal-Wallis 事后检验进一步分析（α=0.05）。
3DP-0、3DP-60 和 HP 标本类型与相应义齿树脂标本上黏附的微生物组之间观察到显著的相互作用（P<.05）。3DP-0、3DP-60 和 HP 标本之间存在统计学差异（P<.05）。与 HP 相比，3DP-0 上的念珠菌黏附率低 3.98 倍（P<.05）。然而，3DP-60 上混合物种微生物和链球菌的黏附率分别高 1.75 倍和 2 倍（P<.05）。扫描电子显微镜显示，与 HP 和 3DP-60 相比，3DP-0 显示出最低的微生物黏附。
义齿基托树脂的黏附亲和力受构建方向而不是不同微生物群的影响。以 0 度构建方向制造的 3D 打印义齿基托树脂对微生物黏附的亲和力较低。当以 0 度构建方向打印时，3D 打印义齿可能会减少微生物黏附。
