Broken front tooth after exam/sonic cleaning; dentist said I need a new crown? (Photos)

A tooth that fractures during a regular cleaning has prior issues. In general, a tooth that has had a root canal is more likely to fracture. For this reason, a crown is usually recommended to protect the tooth. If enough tooth structure remains, a crown would be recommended. However, if there is not enough tooth structure, your options for replacing the tooth would be a bridge or implant. I hope this helps. Click save on the save button below my name, so that you may ask me more questions in the future.

despite the timing, the hygienist isn't at "fault". If cleaning instruments can break the tooth, then the tooth had major issues. From the image, a crown may not work, so consider extraction and an implant or bridge.

The copy of the x-ray is not very clear but shows a dark line at the neck of the tooth. The tooth would need good clinical exam to determine mobility and depth of fracture. Treatment would really depend on how deep the fracture is. Treatment may include a post and core and crown. With deep fractures, a tooth can be saved after a crown lengthening procedure if clinically possible. Allow your doctor to do a detailed clinical exam for those details. Thanks. 

Hi:Generally in my experience any tooth that is damaged in the course of a regular cleaning has had some prior cracks and issues. In your case since the tooth has been root canaled, there is a higher chance of cracking.   Best,Dr. Maddahi

Well, Dear it is difficult to say anything without examine your teeth. If your dentist recommend you crown then you should go for it.