In vitro study of the effect of titanium on Porphyromonas gingivalis in the presence of metronidazole and spiramycin

Septic peri-implantitis is the main clinical complication encountered follo wing the insertion of titanium implants. It may be resistant to conventiona l antibiotic treatments. Reports in the literature about antibiotic behavio r in the presence of titanium remain controversial. They vary from a bacter iostat to a decreased effect of antibiotic. This study examined, in vitro, the viability of Porphyromonas gingivalis, frequently associated with perio dontal diseases, in the presence of titanium and antibiotics (spiramycin an d metronidazole alone or in combination). Viability of P. gingivalis was de termined, versus a standard curve using the Live/dead Baclight Bacteria Via bility Kit(TM) on 96 well microplates. The results of 48 experiments (60 me asurements each) were compiled in a database and compared to each other usi ng the chi (2)p < 0.05 test. When used alone, titanium enhanced bacterial g rowth as the nickel-chrome control. However, when titanium was used in the presence of antibiotics, antibiotics kept their own effects. Even more, tit anium was shown to potentialize the effect of metronidazole. The strengthen ing of effectiveness of metronidazole by titanium may be due to the oxidati on potential of the metal. This chemical property could explain the conflic ting data reported in the literature. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.