With the exception of the mandibular posterior teeth, the crowns of posterior teeth are more facially oriented than their roots. The lingual inclination of the crowns of mandibular molars is helpful in adapting dental hygiene instruments to their lingual surfaces.
a. both statements are true
b. both statements are false
c. first statement is true; second statement is false
d. first statement is false; second statement is true
first statement is true; second statement is false