The Influence of Different Tooth Paste Formulations on Biofilm Formation In Situ

Objectives: In addition to surface cleaning contemporary toothpastes are advertised as biofilm inhibiting agents. The aim of this study was to investigate the influence of different toothpaste formulations on initial biofilm formation in comparison with a basic paste without functionality.
Methods: Bovine enamel (n=240) slabs mounted on acrylic splints were worn by 5 volunteers in their upper jaws for 24h. Specimens placed in the first quadrant (n=4) were brushed after 0.5h, 12 and 23.5h for 30s each time, specimens in the second quadrant were left unbrushed but contaminated with toothpastes slurries. Toothpastes included were: basic paste (B-P: PEG-32, sorbitol, hydroxyethylcellulose, SiO₂, TiO₂, SLS), additionally to ingredients of B-P the other toothpastes contained: herb paste (H-P: carum petroselinum seed oil, curcuma xanthorrhiza root extract, NaF 900ppm), abrasive paste (A-P: RDA: 100, Al-lactate, NaF 1360ppm) chlorhexidine paste (CHX-P: chlorhexidine digluconate 0.05%, Al-lactate, AlF 1360ppm), hydroxyapatite paste (HA-P: hydroxyapatite, Al-lactate, NaF 1360ppm). Brushing with water (W) served as control. Biofilm coverage was analyzed by fluorescence microscopy (FM) using the following scoring system (0: no bacteria, 1: scattered bacteria, 2: small colonies less than 100 bacteria, 3: colonies with more than 100 bacteria, 4: <50% of surface covered, 5: >50% of surface covered). Additionally, biofilm morphology was visualized by scanning electron microscopy (SEM).
Results: Brushed enamel specimens were nearly biofilm free (q1/median/q3, W: 1/1/2, B-P: 1/1/2, H-P: 1/1/2, A-P: 0/1/1, CHX-P: 0/1/1, HA-P: 0/0.5/1), whereas biofilms were found on unbrushed specimens (W: 1/3/4, B-P: 2/3/4, H-P: 3/3/4, A-P: 2/3/4, CHX-P: 1/2/3, HA-P: 1/2/2). The initial biofilm formation was significantly reduced on unbrushed enamel by CHX-P und HA-P compared to B-P (p<0.001). SEM analysis confirmed the FM results.
Conclusions: An in situ dental biofilm model was used to evaluate the influence of different toothpastes on biofilm formation. Toothpastes containing chlorhexidine or hydroxyapatite did show inhibiting effects on initial biofilm formation.