1. Tooth Decay and Stuff

2. Tooth Decay kTooth decay has been present since there have been teeth to decay. kTooth decay, is an infectious disease that damages the structures of teeth kPain kTooth Loss kInfection kDeath kTooth decay has been present since there have been teeth to decay. kTooth decay, is an infectious disease that damages the structures of teeth kPain kTooth Loss kInfection kDeath

4. The Chemistry kTooth decay is Acid/Base chemistry kAcids dissolve the enamel surface of the tooth and create holes in the tooth (cavities) kTooth decay is Acid/Base chemistry kAcids dissolve the enamel surface of the tooth and create holes in the tooth (cavities)

5. What is Enamel? kCalcium hydroxyphosphate, Ca 5 (PO 4 ) 3 OH, also known as mineral apatite kAcid attacks apatite: Ca 5 (PO 4 ) 3 OH(s) (Tooth enamel) + H + (Acid) (aq) → Ca 5 (PO 4 ) 3 + (aq) + H 2 O(l) Reaction is reversible: saliva kCalcium hydroxyphosphate, Ca 5 (PO 4 ) 3 OH, also known as mineral apatite kAcid attacks apatite: Ca 5 (PO 4 ) 3 OH(s) (Tooth enamel) + H + (Acid) (aq) → Ca 5 (PO 4 ) 3 + (aq) + H 2 O(l) Reaction is reversible: saliva

6. Fluoride is your friend kIf fluoride, F-, ions are present in saliva, fluorapatite, Ca5(PO4)3F, also forms. Ca 5 (PO 4 ) 3 + (aq) + F - (aq) → Ca 5 (PO 4 ) 3 F (s) kFluorapatite better than apatite itself (fluoride treatments) kIf fluoride, F-, ions are present in saliva, fluorapatite, Ca5(PO4)3F, also forms. Ca 5 (PO 4 ) 3 + (aq) + F - (aq) → Ca 5 (PO 4 ) 3 F (s) kFluorapatite better than apatite itself (fluoride treatments)

7. Tooth decay, not just candy anymore… kNot bacterial growth in the mouth, but alterations in internal body chemistry kBut candy doesn’t help! kNot bacterial growth in the mouth, but alterations in internal body chemistry kBut candy doesn’t help!

8. What is a Dental Filling? Dental material used to restore the function/integrity/morphology of missing tooth structure -Indirect and direct restoration -Numerous types of methods Dental material used to restore the function/integrity/morphology of missing tooth structure -Indirect and direct restoration -Numerous types of methods

9. Amalgams? An amalgam is a mixture of mercury with another metal or alloy. Most metals are soluble in mercury. Amalgams are commonly used in dental fillings. Dental amalgam consists of three solid phases represented by Ag 2 Hg 3, Ag 3 Sn, Sn 8 Hg An amalgam is a mixture of mercury with another metal or alloy. Most metals are soluble in mercury. Amalgams are commonly used in dental fillings. Dental amalgam consists of three solid phases represented by Ag 2 Hg 3, Ag 3 Sn, Sn 8 Hg

10. Dental Amalgams kDental amalgam is a stable alloy made by combining elemental mercury, silver, tin, copper and possibly other metallic elements. k~65% minimum, silver copper ~6% maximum, copper ~2% minimum, zinc ~25% maximum, tin ~45% liquid mercury kDental amalgam is a stable alloy made by combining elemental mercury, silver, tin, copper and possibly other metallic elements. k~65% minimum, silver copper ~6% maximum, copper ~2% minimum, zinc ~25% maximum, tin ~45% liquid mercury

11. Why Dental Amalgams? -Amalgams withstand chewing loads -Useful for restoring molars in the back of the mouth -They are well tolerated by patients, rare occurrences of allergic response. -Amalgams withstand chewing loads -Useful for restoring molars in the back of the mouth -They are well tolerated by patients, rare occurrences of allergic response.

12. Why Mercury? kNearly every metal is soluble in mercury, iron is the only exception kThus, a malleable paste before solidification can be formed kAs silver dissolves, flexible but firm structure is molded kAdheres to tooth enamel kForms high-strength compound kNearly every metal is soluble in mercury, iron is the only exception kThus, a malleable paste before solidification can be formed kAs silver dissolves, flexible but firm structure is molded kAdheres to tooth enamel kForms high-strength compound

13. Primary controversy kOpponents of dental amalgams with mercury argue the long-term effects of mercury poisoning kCombination of metals should be safe kSome action taken before to ban mercury fillings internationally, but FDA, USPHS, CDC-approved kNot enough research to fully support either side kOpponents of dental amalgams with mercury argue the long-term effects of mercury poisoning kCombination of metals should be safe kSome action taken before to ban mercury fillings internationally, but FDA, USPHS, CDC-approved kNot enough research to fully support either side

14. Controversy

15. Battery in your mouth? kTry this at home!: Aluminum foil pressing against amalgam filling will cause pain kAn electrochemical cell is created when aluminum foil contacts a dental amalgam. Aluminum contacts Sn 8 Hg phase iAluminum becomes the anode and the filling as the cathode. iSaliva acts as an electrolyte. iThe contact between the metals acts as a short-circuit kTry this at home!: Aluminum foil pressing against amalgam filling will cause pain kAn electrochemical cell is created when aluminum foil contacts a dental amalgam. Aluminum contacts Sn 8 Hg phase iAluminum becomes the anode and the filling as the cathode. iSaliva acts as an electrolyte. iThe contact between the metals acts as a short-circuit

16. Dental Filling Corrosion kDental filling can corrode over time kDifferent metals can create an electrical circuit, such as gold and silver. kDental filling can corrode over time kDifferent metals can create an electrical circuit, such as gold and silver.

17. Electricity in Your mouth kSilver and Gold have 3 different solid phases (volt potential): kAg 2 Hg 3 (0.85 v) kAg 3 Sn (-0.05 v) kSn 8 Hg (-0.13) kExperiments you can do at home to create your very own circuit… kSilver and Gold have 3 different solid phases (volt potential): kAg 2 Hg 3 (0.85 v) kAg 3 Sn (-0.05 v) kSn 8 Hg (-0.13) kExperiments you can do at home to create your very own circuit…

18. Experiments kNo, not that… if you have a filling or braces try chewing on aluminum foil.

19. The Corrosion kSn 8 Hg --> Sn 2+ + 2e - kO 2 (g) + 4H + (aq) + 4e - --> 2H 2 O (l) kSn 8 Hg --> Sn 2+ + 2e - kO 2 (g) + 4H + (aq) + 4e - --> 2H 2 O (l)

20. Grills Aren’t Dental Fillings!

21. Sources khttp://www.ada.org/public/topics/fillings.asp#restoring khttp://en.wikipedia.org/wiki/Amalgam kChang, Raymond. Chemistry; McGraw-Hill: San Francisco, 2002. khttp://en.wikipedia.org/wiki/Dental_fillings#Restoration_classifica tions khttp://en.wikipedia.org/wiki/Dental_amalgam_controversy khttp://www.madsci.org/posts/archives/oct2000/973002607.Ch.r. html khttp://adr.iadrjournals.org/cgi/reprint/2/1/71.pdf khttp://www.mercurypoisoned.com/dentists_disciplined/ImageDe ntistNewsletter.jpg khttp://lonestartimes.com/images/Weidenhof/grill.jpg khttp://www.seemygrill.com/f/pics/114744405718814- phpr0RvoL.jpghttp://farm1.static.flickr.com/35/72218577_035bb 4c2b5.jpg khttp://farm1.static.flickr.com/35/72218577_035bb4c2b5.jpg khttp://www.ada.org/public/topics/fillings.asp#restoring khttp://en.wikipedia.org/wiki/Amalgam kChang, Raymond. Chemistry; McGraw-Hill: San Francisco, 2002. khttp://en.wikipedia.org/wiki/Dental_fillings#Restoration_classifica tions khttp://en.wikipedia.org/wiki/Dental_amalgam_controversy khttp://www.madsci.org/posts/archives/oct2000/973002607.Ch.r. html khttp://adr.iadrjournals.org/cgi/reprint/2/1/71.pdf khttp://www.mercurypoisoned.com/dentists_disciplined/ImageDe ntistNewsletter.jpg khttp://lonestartimes.com/images/Weidenhof/grill.jpg khttp://www.seemygrill.com/f/pics/114744405718814- phpr0RvoL.jpghttp://farm1.static.flickr.com/35/72218577_035bb 4c2b5.jpg khttp://farm1.static.flickr.com/35/72218577_035bb4c2b5.jpg