Modern biofilm management: "Control without killing"
introduction
According to the results of the studies to date, hydroxyapatite particles appear to have great potential in caries prophylaxis and plaque control. Frequently, not only the pure active ingredients have been tested in the available studies. Therefore it is necessary to check pure substances for their effectiveness. Although there are also studies for dental care products containing hydroxylapatite that test the pure active ingredient, the focus is on remineralization processes and hypersensitive teeth. Antimicrobial and plaque-inhibiting effects of hydroxyapatite-containing products have so far been proven in clinical studies, but the pure active ingredient hydroxyapatite has not yet been considered.
Question
How big is the plaque-controlling and antimicrobial effect of hydroxyapatite compared to chlorhexidine?
material and methods
Two studies have dealt with this topic. In principle, both studies are similar: Both studies were in situ studies in which test bodies were inserted into the oral cavity of healthy volunteers. These test pieces were worn for a predetermined period of time. The test subjects used different mouthwash solutions. In both cases, a comparison was made between hydroxyapatite and chlorhexidine. After the test bodies had been removed from the oral cavity, they were examined using molecular biology. The aim was to determine to what extent hydroxyapatite and chlorhexidine had reduced bacterial accumulation and whether the microorganisms were still vital.
Results
The results of both studies show that hydroxyapatite reduces the number of bacteria on the teeth to the same extent as a 0.2% CHX solution. While most of the microorganisms die when using CHX, the adhesion to the surface is inhibited with hydroxyapatite and the ecological balance is maintained. The microorganisms are not killed. On the one hand, hydroxyapatite forms a protective layer on the tooth surface and thus inhibits bacterial biofilm formation and, on the other hand, the bacteria accumulate on free hydroxyapatite particles and are therefore not available for deposition on the tooth surface.
Figure: Reduction of bacteria on the teeth: Sketched after Kensche et al.
conclusion
Hydroxyapatite is highly effective in biofilm control and does not affect the ecological balance.
