How Does Your Mouthwash Measure Up: Effects of Specific Mouthwashes on
Staphylococcus epidermis and Bacillus subtilus
Mouthwash Lab Report
This experiment was done in order to find out which mouthwash killed the bacteria Staphylococcus epidermis and Bacillus subtilus the best. The mouthwashes used were Scope (clean mint baking soda), Listermint with fluoride, Cepacol, Rembrandt, and Therasol. Water was used as a control for the experiment. It allowed students to practice using T -values to determine significance of mouthwash effectiveness. The experiment also determined the active ingredient in the better mouthwash. My own hypothesis was that Scope would ...view middle of the document...
Bacillus subtilus is a non-pathogenic, rod-shaped, gram-positive bacterium that is capable of producing endospores during harsh conditions. It is often times used to produce insect toxins, peptide antibiotics, and anti- fungals used in agricultural production (MICRON). It is a very well known bacterium; scientists have successfully sequenced strain number 168 (EBI). Although neither of these bacteria is usually found in the mouth, they are easy to grow and maintain in the laboratory environment. My own hypothesis for this experiment is that Scope will work the best in killing or inhibiting both of the bacteria used. Basis for this suggestion is the popularity among consumers and it's constant claim that it works best
Materials and Methods
The Microbiology Lab: Comparison of the Antibacterial Activity of Several Mouthwashes provides a list of materials needed to perform this experiment (Browder 2). It also provides the procedure one must follow in order to complete the experiment (Browder 3). It does, however, leave out the careful instructions needed to prevent contamination of the petri plates. There were rules that had to be followed in order to keep the plates that grow the bacteria sterile. Handling the bottom of the pipettes that were used would cause unnecessary contamination. The petri plates that were used had to be kept closed as much as possible. Opening them too much or leaving them open would cause airborne contaminants to pollute the plate. The tops of the tubes that were used and the tweezers had to be sterilized before each use. Simply running each of them through a flame kills all unwanted materials. After reviewing these rules, one could continue with the experiment exactly how it was written in the handout.
Scope (Clean Mint Baking Soda), Listermint with fluoride, Cepacol, Rembrandt, and Therasol were the mouthwashes used in our experiment. We were to measure the zone of inhibition produced by each individual mouthwash. This zone is the area in which the bacteria were killed, producing a clear spot. In this experiment, the control group was water. The water would have no effect on the bacteria. This would allow one to compare the effects of the mouthwashes with one that proved obsolete. By knowing what the agar would look like with no effects it would be easier to notice those that had reactions to the bacteria.
. The results of my experiment were as follows. Therasol caused the largest zone of inhibition on Bacillus subtilis. This occurred at the 95% significance. ...