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Healthy Gums. Gingivitis. Moderate Periodontitis. Advanced Periodontitis. Mouthwash Use. $2 Billion a Year on Dental Products Toothpaste Mouthwash Dental Floss/Toothbrushes $885 Million - total annual spending on oral antiseptics/rinses (ACNielsen, 2002)*. Purpose of Mouthwash.
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Healthy Gums Gingivitis Moderate Periodontitis Advanced Periodontitis
Mouthwash Use • $2 Billion a Year on Dental Products • Toothpaste • Mouthwash • Dental Floss/Toothbrushes • $885 Million - total annual spending on oral antiseptics/rinses (ACNielsen, 2002)*
Purpose of Mouthwash • “Kills germs that cause bad breath” • Halitosis • Volatile Sulfur Compounds (VSC’s) • Anaerobic, Sulfur Producing • Fight Plaque & Gingivitis • Bacteria Feed on Sugars • Produce Acid
Antimicrobial Overuse • We Overuse Antibiotics • FDA calls it “one of the world's most pressing public health problems” (www.fda.gov) • 2 Million People Acquire Infections in Hospital • ½ Caused by Antibiotic Resistant Bacteria • Kills 90,000+ People Annually
Antimicrobial Resistance • Bacteria Change • Reduces/Eliminates Effectiveness of Antimicrobials • Why is this a problem? • Longer Illness • Need for More Antibiotics • Death
How does this happen? Drugs place stress on environment: killing defenseless bacteria.
How does this happen? “Selecting” those that can overcome the stress
How does this happen? Resistant bacteria multiply and become dominant strain
What does this have to do with Mouthwash? • Mouthwash & Antibiotics are Antimicrobials • Kill or Inhibit Growth
Overall Problem: Does daily exposure to mouthwash induce antimicrobial resistance in native mouth bacteria?
Antimicrobial Resistance of Native Mouth Bacteria Antimicrobial Resistance of Native Mouth Bacteria Alison Burchett Centralia High School
Overall Hypothesis: Regular exposure to mouthwash may induce antimicrobial resistance in native mouth bacteria.
Test II: Affect of Mouthwash on Mouth Bacteria • Question: Which mouthwash(es) inhibit the growth of most but not all mouth bacteria? • Hypothesis: • Listerine • Setup: • Mouth Bacteria • Petri Plates (Tooth/Tongue Surface)
Listerine (Cool Mint) R=0.89 Listerine (Natural Citrus) R=0.695 Scope (Cool Peppermint) R=1.48 ACT R=1.59 Crest Pro Health R=1.56 Safeway Antiseptic Mouthwash R=0.805 Listerine (Fresh Burst) R=0.76 Tom’s of Maine R=0.0 20.6% Alcohol Solution R=0.0 Scope (Mint) R=1.29 Listerine (Original) R=0.84 1.5% Hydrogen Peroxide Solution R=3.38
Conclusions • Listerine • Least Effective in Preventing Growth • (Of Successful Mouthwashes)
Test III: Effect of Mouthwash Concentration • Question: What concentration of Listerine will kill/inhibit growth of most but not all bacteria? • Hypothesis: • 40% Most • 50% All
Test III: Effect of Mouthwash Concentration • Setup: • Listerine • Applied Listerine to bacterial solution • 0%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% • 30 seconds • Mediums: • Blood Agar • Bacto Agar • LB Agar
0% Listerine 20% Listerine Bacto Agar Blood Agar LB Agar 30% Listerine
Conclusions • Mediums • All Mediums are Appropriate • Somewhere Between 20%-30% Kills Most • Above 30% Bacteria Can’t Grow
Test IV: Antimicrobial Resistance of Native Mouth Bacteria • Question: Does daily exposure to mouthwash induce bacterial resistance? • Hypothesis: Samples of exposed bacteria will show signs of resistance (have more bacterial growth)
Setup: • Growth Rates • Optical Density • % Transmittance and Absorbance • 600 nm • LB Broth • Listerine • 10 Applications, 1 every hour • Ending Concentration = 14% • 12 hour growth period
% Transmittance of bacterial growth Without Mouthwash With Mouthwash
Test IV: Antimicrobial Resistance of Native Mouth Bacteria-Trial II • Repeated Trial • More Samples • Application • More Mouthwash Per Application • Every Half Hour • Ending Concentration = 9.1%
Discussion • Growth Rate • Time Constraints • Plaque Formation vs. Cloudy Growth • Hard to Get Consistent Readings • Bio Mass
Questions • Is the bacteria resistant to just some or all of the active ingredients? • Are there different types of resistance?
Test V: Resistance to Individual Active Ingredients • Question: Do mouth bacteria become more resistant to some antimicrobial ingredients than others? • Hypothesis: Exposed samples will show resistance to some but not all active ingredients. (Listerine)
Setup: • Individual Ingredients • Thymol 0.064% • Eucalyptol 0.092% • Methyl Salicylate 0.060% • and Menthol 0.042.% • 1.7 mL Eppi Tubes • 1 mL LB Broth • Start Aerobic, End Anaerobic • Took Optical Density
%T and % of Potential GrowthIndividual Active Ingredients Sample: Mouthwash User 1 Mouthwash User 2 Non-User Application Δ%T %PG Δ%T %PG Δ%T %PG
%T and % of Potential GrowthIndividual Active Ingredients Sample: Mouthwash User 1 Mouthwash User 2 Non-User Application Δ%T %PG Δ%T %PG Δ%T %PG
Analysis • Possible Difference • Menthol-Most Resistance • Need To Do Follow Up Tests
Discussion • Samples Showed Different Types of Resistance • Dichotomy vs. Spectrum • Treat Mouth as System • Multiple Occurrences • Other Ingredients • Benzoic Acid • Sodium Benzoate • Known Antimicrobials • Gum Chewing • Xylitol
Limitations • Samples • Different People, Different Bacteria • Oral Hygiene Habits • Poorly-Controlled Variables • Inoculation • Confidence
Future Tests • Relationship Between Sample Growth and Time of Sample Collection • Brushing • Eating • Xylitol • Toothpaste With Mouthwash • Genetically Modified “Good” Bacteria • Resistant to Mouthwash
Conclusion Bacteria exposed to mouthwash on a daily basis showed signs of resistance. What does this mean? Mouthwashes may become less effective; no longer work.
Acknowledgements • My Parents, Tom and Patty Burchett • Travis Lankow • Centralia School District • Henri Weeks • Mike Stratton • For his never-ending enthusiasm and ability to always make science exciting.
Bacterial Swapping (Kissing) Microbial Resistance Bacterial Strains Obsolete Dentists Environmental Stress Topic Evolution Listerine Alternative Resistance Tests Hourly Applications Inoculation Spectrometer %Transmittance t-Tests Xylitol Questions?
Test I: Effectiveness of Mouthwash • Controlled Variables: • One Bacterial Strain • E.coli DH5 • Growth Medium • LB Broth Solution • 12 Different Mouthwashes • Positive and Negative Controls • Hypothesis: • Mouthwash = Less Growth • More Alcohol = More Effective • Listerine
Control (no mouthwash) Crest Pro Health Scope (mint) 20.6% Alcohol Solution Listerine (Original) 1.5% Hydrogen Peroxide Solution Listerine (Fresh Burst) Tom’s of Maine Listerine (Natural Citrus) ACT Scope (Cool Peppermint) Listerine (Cool Mint) Safeway Antiseptic Mouth Rinse
Conclusions • Alcohol • Didn’t seem to work • Didn’t support hypothesis • Cetylpridinium Chloride • Scope • Crest Pro Health • Hydrogen Peroxide • Flavor and coloring had no effect
My Theory on Resistance and Kissing Bobby’s Mouth Cindy’s Mouth
My Theory on Resistance and Kissing Bobby’s Mouth Cindy’s Mouth
My Theory on Resistance and Kissing Bobby’s Mouth Cindy’s Mouth
My Theory on Resistance and Kissing Bobby’s Mouth Cindy’s Mouth
Types of Resistance Genetic Mutation DNA Changes • Drug Resistant TB
Types of Resistance Transformation (Microbial Sex) • Penicillin Resistant Gonorrhea