[Effect of three surface modification techniques of pure titanium on bacteria adhesion and ultrasonic cleaning...

To evaluate the bacteria adhesion behavior and ultrasonic cleaning efficacy on pure titanium modified with 3 different techiques.

Pure titanium disks with mechanically polished surfaces(MP), titania nanotube surfaces(TNT)and sandblast-large grit and acid-etched surfaces(SLA)were used as substrates. The surface characteristics of the 3 types of specimens were detected. The disks of all groups were co-cultured with Porphyromonas gingivalis(Pg)and microcosm for 1 day and 5 days respectively. The cell viabilities of bacteria attached to the 3 types of surfaces were tested. The remaining bacteria on different surfaces after ultrasonic treatment were observed through live/dead bacteria staining.

MP and SLA surfaces demonstrated a micro-scale structure, while TNT surfaces showed a nano-scale structure. The surface roughness of SLA specimen was the highest([1.62 ± 0.13]μm), and that of MP([0.81 ± 0.10]μm)and TNT specimen([0.792 ± 0.080]μm)were relatively lower and showed no statistical difference(P >0.05). At 1 and 5 d, the cell viability and the biomass of Pg attached to MP surfaces were as low as 1 829±210 and 13 811±3 110 and A570 value were 0.80±0.35 and 1.56±0.30 respectively. At 1 d, the cell viability of microcosm adhered on MP and TNT surfaces were lower(63 943±6 990 and 69 860±5 555)than that on the SLA surface, and the biomass of microcosm adhered on MP surfaces demonstrated the lowest value(A570 value 5.84±0.60). At 5 d, both the cell viability and biomass of micorcosm adhered on the three surfaces were of no statistical difference(P<0.05). The remaining bacteria on TNT surfaces were the least in the three groups and distributed sporadically after ultrasonic treatment. The remaining bacteria on all surfaces increased with culture time.

Both surface topography and roughness affect early bacteria adhesion. However, this effect can be weakened as the biofilm getting mature. The surface topography can significantly affect the mechanical cleaning efficacy of the biofilm. TNT surface reveals a lower adhesion of microcosm and a higher efficacy of ultrasonic cleaning compared to MP and SLA surfaces.