LAUSR

OBJECTIVES To evaluate the effects of 8% arginine-containing toothpaste on the dental plaque of no caries (NC) and high caries (HC) individuals in situ. METHODS 6 no caries (DMFT=0) and 6 high caries (DMFT≥6) individuals wearing a self-developed in situ dental plaque acquisition device were involved in a randomized double-blinded crossover study for 6 weeks: including lead-in (1 week), arginine-free (2 weeks), washout (1 week) and arginine-active (2 weeks) stages. The in situ plaque samples were collected at the endpoint of arginine-free and arginine-active stages and subjected to lactic acid production, metabolic activity, live/dead bacteria ratio and total biofilm biomass detections. RESULTS The arginine-containing dentifrice reduced lactic acid production significantly in both the NC and HC groups, while the inhibitory abilities in the HC group were stronger than that in the NC group. In addition, the arginine-containing dentifrice didn't significantly decrease the metabolic activity, live/dead bacteria ratio and total biofilm biomass in either the NC or the HC group. CONCLUSIONS Arginine-containing toothpaste can significantly reduce the lactic acid production from the in situ plaques to a low level without changing the metabolic activity, live/dead bacteria ratio and total biofilm biomass through a critical clinical randomized double-blinded crossover study. CLINICAL SIGNIFICANCE Arginine is a potential ecological prevention and control agent for dental caries. Meanwhile, the in situ model is an easy and pragmatic way to evaluate oral hygiene products (clinical trial registration: ChiCTR-INR-16010226).