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Chemistry Application Essay

#31 Chemistry 1 Honors Mr. Ceccerelli 4 January 2013

 **__Tooth Decay and Fluoridation__**  I am sure everyone has had a cavity before or at least knows someone who has had a cavity. Tooth decay affects 95% of individuals in America. To many peoples surprise cavities and tooth decay actually have a lot to do with chemistry, not just whether you eat a lot of candy and sweets.

 Tooth enamel is the hardest substance in the human body made of a mineral called hydroxyapatite also known as mineral apatite, Ca10(PO4)6(OH)2. When acids dissolve the tooth enamel, cavities are formed. The equation for the process is Ca10(PO4)6(OH)2 (s)+8H+ (aq) ---> 10Ca+2 (aq) +6HPO4-2 (aq) + 2H2O (l). After this reaction occurs the Ca+2 and HPO4-2 ions get washed away out of the enamel by saliva in the mouth. The action of specific bacteria on sugars and other carbs that are in the plaque of our teeth attacks the hydroxyapatite.

 This is when the fluoride comes in. Fluoride is found in drinking water, 80% of toothpastes, mouthwash, and fluoride supplements. When fluoride is introduced, it reacts with hydroxyapatite and forms fluoroapatite, Ca10(PO4)6F2. The F- ion replaces the Hydroxyl (OH-) in hydroxyapatite. This is beneficial because it is much more resistant to acid attacks. The fluoride ion has a weaker Bronsted-Lowry base, defined as anything that accepts H+ ions,than hydroxide ion. Also, because fluoride is so beneficial it is added to water in the public water supply at 1mg/L (1ppm). The fluoride can be added as sodium fluoride (NaF) or sodium fluorosilicate (Na2SiF6). Adding either of these compounds to water releases the fluoride ion into the water. In toothpastes, the following compounds can be added, Sodium fluoride (NaF), sodium monofluorophosphate (Na2PO3F), and stannous fluoride (SnF2). These are added at .7 to 1.2 parts per million.

 A process called mineralization adds fluoride, calcium, and phosphate to the enamel layer in teeth. These minerals come from food and water that we consume. Fluoride not only protects against acids but also speeds up remineralization. This is a major benefit because tooth decay can lead to tooth loss, pain, infection, and even death. The most common fix to tooth decay involves drilling infected tooth out and filling it with a cap. All in all, fluoride is extremely beneficial in preventing tooth enamel decay.

__Works Cited __ "Nature'd Way to Prevent Tooth Decay." //Centers for Disease Control and Prevention//. Centers for Disease Control and Prevention, n.d. Web. 03 Jan. 2013.

"Fluoride Action Network." //Fluoride Action Network//. Fluoride Action Network, n.d. Web. 03 Jan.2013.