Upload
erin-lambert
View
220
Download
5
Tags:
Embed Size (px)
Citation preview
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
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?
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)
Tom’s of
Maine
R=0.0
1.5% Hydrogen Peroxide Solution
R=3.38
20.6% Alcohol Solution
R=0.0
Crest Pro
Health
R=1.56
Listerine (Cool Mint)
R=0.89ACT
R=1.59
Listerine
(Natural Citrus)
R=0.695
Listerine
(Fresh Burst)
R=0.76
Listerine
(Original)
R=0.84
Scope (Mint)
R=1.29
Safeway Antiseptic
Mouthwash
R=0.805
Scope (Cool Peppermint)
R=1.48
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
• 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
Test III: Effect of Mouthwash Concentration
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
Sample Δ%T Mean
Non-mouthwash Users 14.9
Non-mouthwash Users 88.8 63
Non-mouthwash Users 85.4
Mouthwash Users 93.9
92Mouthwash Users 89.5
Non-mouthwash Users 21.8
Non-mouthwash Users 11.5 18
Non-mouthwash Users 21.6
Mouthwash Users 75.7
70Mouthwash Users 63.8
% Transmittance of bacterial growth
Without Mouthwash
With Mouthwash
•Repeated Trial•More Samples•Application
–More Mouthwash Per Application
–Every Half Hour–Ending Concentration = 9.1%
Test IV: Antimicrobial Resistance of Native Mouth
Bacteria-Trial II
% Transmittance of Bacterial Growth
Sample
Without Mouthwash
Stress
With Mouthwash
Stress% of
Potential AverageStandard Deviation
MW User 1 79.9 81.9 97.6%
MW User 2
MW User 3
MW User 4
MW User 5
Non-User 6
Non-User 7
Non-User 8
Non-User 9
Non-User 10
% Transmittance of Bacterial Growth
Sample
Without Mouthwash
Stress
With Mouthwash
Stress% of
Potential AverageStandard Deviation
MW User 1 79.9 81.9 97.6% 94.7% 30%
MW User 2 92.6 90.7 102.1%
MW User 3 86.5 87.7 98.6%
MW User 4 9.5 20.4 46.6%
MW User 5 53 41.2 128.6%
Non-User 6 73 66 110.6% 59.5% 48%
Non-User 7 17.9 82 21.8%
Non-User 8 77.2 69 111.9%
Non-User 9 3.4 20.9 16.3%
Non-User 10 22.1 60.1 36.8%
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 Growth
Individual Active Ingredients Sample: Mouthwash User 1 Mouthwash User 2 Non-User
Application Δ%T %PG Δ%T %PG Δ%T %PG
LB Broth 72.1 0 14.3 25.6
Water 57.4 80% 27.7 194% 31.8 124%
Listerine 18.2 25% 17.4 122% 17.4 68%
Menthol 78.4 109% 2.7 19% 1.5 6%
Methyl Salicylate 74.9 104% 1.9 13% 0 0%
Eucalyptol 76.1 106% 1.3 9% 0 0%
Thymol 69.7 97% 0 0% 0 0%
Alcohol 71.9 100% 0 0% 0 0%
%T and % of Potential Growth
Individual Active Ingredients Sample: Mouthwash User 1 Mouthwash User 2 Non-User
Application Δ%T %PG Δ%T %PG Δ%T %PG
LB Broth 72.1 0 14.3 25.6
Water 57.4 80% 27.7 194% 31.8 124%
Listerine 18.2 25% 17.4 122% 17.4 68%
Menthol 78.4 109% 2.7 19% 1.5 6%Methyl Salicylate 74.9 104% 1.9 13% 0 0%Eucalyptol 76.1 106% 1.3 9% 0 0%Thymol 69.7 97% 0 0% 0 0%
Alcohol 71.9 100% 0 0% 0 0%
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.
Questions?
• Bacterial Swapping (Kissing)
• Microbial Resistance
• Bacterial Strains• Obsolete
Dentists• Environmental Str
ess• Topic Evolution• Listerine
• Alternative Resistance Tests
• Hourly Applications
• Inoculation• Spectrometer• %Transmittance• t-Tests• Xylitol
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)
20.6% Alcohol Solution
1.5% Hydrogen Peroxide Solution
Tom’s of Maine
ACT
Listerine (Cool Mint)
Crest Pro Health
Scope (mint)
Listerine (Original)
Listerine (Fresh Burst)
Listerine (Natural Citrus)
Scope (Cool Peppermint)
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
Sources• http://www.dentalgentlecare.com• http://www.enexus.com/gumdisease/• http://www.fda.gov• http://www.cdc.gov• Burdon, Kenneth. Text Book of Microbiology. 4th ed.
New York: Macmillan, . • Et. Al, . Microbiology. 2nd ed. Hagerstown: Harper &
Row, . • Et. Al, . Microbiology. 2nd ed. New York: Holt, Rinehart,
and Winston, • Et. Al, . Antibiotics. Philadelphia: JB Lippincott Co., . .
Listerine• $350 Million in Yearly Sales• Most Commonly Used in the
World• 1921-First Over-The-Counter
Oral Rinse– Invented Term “Halitosis”