Odontoblast nuclei displacement into adjacent dentinal tubuli is thought to be
1. a reversible pathologic condition.
2. due to increased intrapulpal tissue pressure.
3. due to contraction of collagen fibres.
4. more frequent following the use of air coolant rather than water coolant.
5. one of the first histological changes following operative trauma

All of the above

(1) (2) (3)

(1) and (3)

(2) and (4)

(4) only