Fill in the Blanks Tooth partsOnline version Complete by Mª Ángeles Martín 1 part through firmly Blood pulp pulp ligament periodontal cells cementum tissue dentin tooth substance enamel teeth gums teeth 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 .