This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
The undesirable side effect most commonly associated with the use of finger spring to tip the crown of a tooth is: 
Select and explain. 
A. Pain, B. Gingival irritation, C. Tendency for the root apex to move in the direction opposite from the crown, D. Tendency for the tooth to intrude
C: Tendency for the root apex to move in the direction opposite from the crown
Answer: C: Tendency for the root apex to move in the direction opposite from the crown 
Explanation: Excessive forces can cause unwanted tooth movement. Unwanted excessive tipping of maxillary central incisor root is caused by over activation of finger spring.