Fill in the Blanks Tooth partsOnline version Complete by Mª Ángeles Martín 1 firmly cells teeth ligament gums substance part tooth pulp cementum through Blood periodontal pulp enamel tissue teeth dentin The is the hardest , white outer of the . The is a layer underlying the enamel . It is made of living , which secrete a hard mineral . The is the softer , living inner structure of . vessels and nerves run the of the teeth . The is a layer of connective that binds the roots of the teeth to the and jawbone . The is a tissue that helps hold the tightly against the jaw .