Method:
Plaques were cultivated on titanium (Ti) or hydroxyapatite (HA) discs in medium inoculated with human saliva before exposing to slurries of CT, PH or a dentifrice without additional antibacterial actives (CP). Total anaerobes, aerobes/facultative anaerobes or Gram-negative anaerobes from treated plaques were cultured using selective media. Viability mapping was performed by staining exposed plaques with a fluorescent viability stain and quantifying viable and non-viable biomass using epifluorescence microscopy. Viability profiling by confocal microscopy evaluated three-dimensional effects within the biofilm.
Result:
Ti and HA supported dense plaques (6.3 and 7.2 log10 total anaerobes cfu/cm2, respectively), with higher proportions of Gram-negative anaerobes in Ti-grown plaque than HA (11.8% and 2.6%, respectively). Exposure to CT resulted in greater inactivation of Ti-grown plaque than CP or PH (92.4%, 9.9% and 39.5% reductions in total anaerobes, respectively, compared to a treatment-free control). Viability mapping confirmed that exposure of Ti-grown plaque to CT achieved greater viability reductions than PH or CP (83.5%, 20.3% and 48.9% reductions, respectively, p<0.05). Viability profiling demonstrated marked differences in viability (47.3%, 75.9% and 77.3% viable for CT, PH and CP, respectively), with extensive zones of non-viable biomass through the CT-treated plaque depths.
Conclusions:
This study demonstrates that dense, complex and highly-viable plaques grow on titanium surfaces. Further, CT exposure resulted in significantly greater, more widespread reductions in the viability of Ti-grown plaque than PH or CP.