Influence of a mouthwash containing hydroxyapatite microclusters on bacterial adherence in situ

The aim of the present study was to investigate the efficacy of a new preparation in dental prophylaxis containing zinc-carbonate hydroxyapatite microclusters (Biorepair) for oral biofilm management. Initial biofilm formation was carried out in situ with bovine enamel slabs fixed to individual upper jaw splints worn by six subjects. Rinses with the customary preparation as well as with subfractions (hydroxyapatite microclusters in saline solution; liquid phase without particles) were adopted for 1 min in situ after 1 min of pellicle formation, and the bacterial colonization was recorded after 6 h and 12 h, respectively. Rinses with chlorhexidine served as a reference. The adherent microorganisms were quantified and visualized using DAPI staining and live-dead staining (BacLight). Furthermore, the effects on Streptococcus mutans bacteria were tested in vitro (BacLight). Application of the customary preparation and of the separate components distinctly reduced the initial bacterial colonization of the enamel surface in situ as visualized and quantified with all techniques. After 12 h, 1.3 x 10(7) +/- 2.0 x 10(7) bacteria/cmA(2) were detected on unrinsed control samples with DAPI staining; 2.4 x 10(6) A +/- 3.3 x 10(6) after application of Biorepair (12 h after CHX-rinse; 1.3 x 10(5) A +/- 9.2 x 10(4)). Also, pure hydroxyapatite microclusters in saline solution (2.1 x 10(6) A +/- 3.0 x 10(6)) as well as the liquid phase without particles (5.1 x 10(5) A +/- 3.3 x 10(5)) reduced the amount of adherent bacteria. Furthermore, antimicrobial effects on S. mutans were observed in vitro. The preparation is an effective compound for biofilm management in the oral cavity due to antiadherent and antibacterial effects. The tested mouthrinse seems to be a reasonable amendment for dental prophylaxis.