CECmisc.50


TITLE:    WHAT CAUSES TOOTH DECAY

AUTHOR:   MELODIE HILL, Lewis Arriola Elemen., Cortez, CO

GRADE LEVEL/SUBJECT:  Health:   Grades  2-6

OVERVIEW:  Tooth decay is one of the most common diseases in
Colorado today.  To help students understand the causes and
implications of tooth decay, this activity uses vinegar and
egg shells in a simulation of teeth decomposition.

OBJECTIVES:  Students will be able to:
1.   Show the parts of a normal tooth.  These include
     enamel, pulp, dentin, crown, neck, and root.
2.   Identify the causes of mouth acids (saliva and food
     particles).
3.   Show the effects of weak acids on calcium as an example
     of weak mouth acids on teeth enamel which contains
     calcium as a main ingredient.
4.   Chart micro-organism growth and decline as the food
     supply runs out.
5.   Describe factors that inhibit micro-organism growth
     (cold, sunshine, sterilization, etc.)
6.   Describe ways that micro-organisms are used
     successfully.

RESOURCES:Paper plates, one per child, small container or
jar, tape, egg shells, crackers, bread, vinegar, graph
paper, hand mirrors, worksheet pages, teeth if
available.Student materials:  Pencil or other writing
utensil.

ACTIVITIES:
1.   Have students eat a cracker and spit it out on a paper
     plate.  What happened? Why?  Place cracker on paper
     plate.  Add water.  What happened?  Why?  Place another
     cracker on paper plate.  Add vinegar.  It should
     dissolve even more than water showing that saliva
     contains a weak acid similar to vinegar.
2.   Using tape, label a small container (baby food jar)
     with students name.  Place egg shell in jar.  Explain
     that teeth enamel is made of the same stuff (calcium)
     as egg shell.  Pour small amount in vinegar in, enough
     to cover half of shell.
3.   Cap  jars and label the date on the lid.  Let sit
     several days.  Observe changes every day. Have students
     draw egg shell enlarged an graph paper.
4.   Have students bring in lost teeth of their own.  These
     can even be animal teeth.  Show crown, neck and root.
     Split a tooth if possible to show enamel, pulp and
     dentin.  Use worksheet to reinforce.
5.   After several days blacken in squares on graph paper to
     show holes in egg shell.  Explain that the holes are
     places where the acids dissolved the calcium.  Explain
     that enamel on outside of teeth is also made of
     calcium.
6.   Using a small hand mirror, have students look at their
     own teeth.  Note areas that appear black or dark.  Note
     fillings or caps on worksheet page.  Explain that back
     teeth (molars) are more at risk because of gum chewing,
     etc.
7.   Have students compare teeth charts.