After each dental hygiene method, I obtained a dental bacterial sample by scraping my front teeth with a sterile needle. It was then swabbed on a petri dish and incubated for 48 hours. Finally, the surface area of bacterial growth was measured for each dental hygiene method. A gram stained slide was made from each dental hygiene petri dish. These slides were microscopically examined using a 40x oil immersion lens.
Rotary tooth brushing decreased the most surface area of dental bacteria from a control of 664 mm^2 to 11 mm^2/ 4 trials. Mouthwash decreased the surface area of dental bacteria to 24 mm^2/ 4 trials and manual tooth brushing decreased the surface area of dental bacteria to 27 mm^2/ 4 trials. Dental floss decreased the least surface area of dental bacteria to 120 mm^2/ 4 trials. Manual and rotary tooth brushing decreased the variety of dental bacteria to only gram-positive cocci. Mouthwash and dental floss decreased the variety of dental bacteria to gram-positive cocci, gram-negative cocci, and gram-positive/negative bacilli.
My conclusion is that rotary tooth brushing is the most effective in decreasing the number and variety of dental bacteria. Mouthwash and manual tooth brushing were intermediate in decreasing the number of dental bacteria. Dental floss was the least effective in decreasing the number and variety of dental bactera.
This experiment is about dental bacteria and which dental hygiene method reduces the most bacteria on my teeth.
Science Fair Project done By Justin J. Persky