激光选区熔化钛表面不同形貌对口腔链球菌黏附的影响

目的探讨激光选区熔化（SLM）制造的钛试件表面不同形貌对变异链球菌和血链球菌黏附的影响。 方法通过喷砂、碱处理和阳极氧化在SLM钛片表面制备纳米网（NN组）和纳米管（NT组）表面形貌，并与喷砂SLM钛片（SB组）及未处理SLM钛片（SLM组）进行对比，通过扫描电镜、表面形貌分析仪、表面接触角测试仪对各组钛片表面形貌、粗糙度和亲水性进行表征。将各组钛片与变异链球菌和血链球菌共同培养24 h。通过菌落形成单位计数及细菌荧光染色分析比较不同表面形貌SLM钛片上2种细菌在的黏附活、死菌量及活死菌总量，进而评价SLM钛表面不同形貌对口腔链球菌黏附的影响。 结果SLM组表面为波浪状起伏微米形貌，SB组表面为沟嵴状起伏微米形貌；NN组表面和NT组表面形成了纳米网和纳米管结构。经表面处理的SB组、NN组和NT组较SLM组表面粗糙度降低（Ra_SB= 2.87 μm，Ra_NN= 2.90 μm，Ra_NT= 2.65 μm，Ra_SLM= 7.19 μm），亲水性提高（SLM组、SB组、NN组和NT组表面水接触角分别为76.90°、64.47°、23.17°和44.13°）。菌落形成单位计数结果显示，NT组表面变异链球菌和血链球菌的细菌密度为661.29和668.45 CFU/mm²，为各组最低，且与其余组差异具有统计学意义（P<0.05）；细菌荧光染色结果显示，NT组表面变异链球菌和血链球菌的活死菌总平均荧光强度为281.17和303.58，亦为各组最低，且与其余组差异具有统计学意义（P<0.05）；NN组表面变异链球菌和血链球菌死菌比例为0.47和0.62，均显著高于其余各组（P<0.05）。 结论在SLM起伏微米形貌基底上，阳极氧化纳米管具有较强的抗细菌黏附性能，碱处理纳米网抗细菌黏附性能弱于阳极氧化纳米管，但具有一定杀菌性能。

Influence of different titanium surface topographies caused by selective laser melting on the adhesion of oral Streptococcus

ObjectiveTo investigate the influence of different titanium surface topographies caused by selective laser melting (SLM) on the adhesion of oral Streptococcus. MethodsNanonet (NN) and nanotube (NT) topographies were constructed by sandblasting, anodization and alkali treatment on SLM titanium discs. These two groups were compared with sandblasting (SB) and untreated SLM titanium discs. Surface topography, roughness and hydrophilicity were analyzed with a scanning electron microscope, a profilometer and a contact angle measuring device. To evaluate the adhesion of oral Streptococcus on different surface topographies on SLM titanium, Streptococcus mutans (S.mutans) and Streptococcus sanguinis (S.sanguinis) were incubating on the sample surfaces for 24 h. Bacteria colony counting and staining were conducted to check the amount of live and dead bacteria as well as the total amount of bacteria adhered to the surfaces. ResultsThe SLM samples showed a microrough waving surface, while SB samples showed microrough waving surface with grooves and ridges. Nanotubes and nanonets were formed on the surfaces of NT and NN samples. The surface roughness of SB, NN and NT samples was lower than that of SLM samples (Ra_SB= 2.87 μm, Ra_NN= 2.90 μm, Ra_NT= 2.65 μm, Ra_SLM= 7.19 μm) , while their hydrophilicity was higher than that of SLM samples (the water contact angles of SLM, SB, NN and NT samples were 76.90°, 64.47°, 23.17°, 44.13°, respectively) . The results of bacteria colony counting showed that NT samples had the lowest bacteria density of both S.mutans (661.29 CFU/mm²) and S.sanguinis (668.45 CFU/mm², P<0.05) . The results of bacteria staining also showed that NT samples had the lowest total mean fluorescence intensity (P<0.05) , which were 661.29 CFU/mm² for S.mutans and 668.45 CFU/mm² for S.sanguinis. The NN samples had the highest proportion of dead bacteria (P<0.05) , which were 0.47 for S.mutans and 0.62 for S.sanguinis. ConclusionsThe anodized nanotubes on microrough SLM substrate exhibited preferable anti-adherence efficacy on oral Streptococcus. The anti-adherence efficacy of alkali treated nanonets on microrough SLM substrate was inferior to anodized nanotubes. However, it possessed certain bactericidal capability.