Antimicrobial activity of Salvia officinalis against Streptococcus mutans causing dental implant failure: An in vitro study

Aim: The current study aimed at examining the antimicrobial activity and efficacy of Salvia officinalis against Streptococcus mutans that affect titanium dental implant (Ti6Al4V). Materials and Methods: An in vitro study was conducted in which Salvia officinalis essential oil was investigated against antibiotic-resistant S. mutans. Salvia officinalis chemical components were analyzed using the gas chromatography–mass spectrometry (GC–MS) method. Six samples of titanium dental implant (Ti6Al4V) were manufactured using direct metal laser sintering (DMLS) manufacturing technology. The bioassay method was conducted to confirm the inhibitory effect of Salvia officinalis essential oil against S. mutans; microdilution assay was also performed on six samples to examine the minimum inhibition concentration (MIC). Two samples that showed MIC were selected to undergo scanning electron microscopy (SEM) to investigate or observe bacterial structural changes upon treatment with Salvia officinalis essential oil. Results: Salvia officinalis essential oil exhibited a great inhibition diameter of 40 mm against S. mutans, and it showed an MIC value of 12.5 μg/mL on the titanium implant material surface and an MIC of 5 μg/mL. The SEM results have shown drastic structural changes on S. mutans on treatment with Salvia officinalis essential oil at its MIC value. Conclusion: Salvia officinalis essential oil has shown potential to be used as an antimicrobial agent; therefore, essential oils in future can be considered possible antimicrobials because of the structural changes that they induce on bacterial cells. Salvia officinalis essential oil, which was investigated in the current study, succeeded in penetrating the bacterial cell wall and caused disruption; therefore, the essential oil stands a chance of being used to inhibit the growth of S. mutans bacteria.