Table 2.

Evaluation criteria for the histopathological analysis of pulp-dentine complex, PDL, and bone responses after lateral root perforation and mechanical pulp exposure in rats.

0	1	2	3
Inflammatory cell infiltration of the pulp
No necrosis, No hyperemia (no blood vessels and congestion)	No necrosis, normal cellularity, and a minimum amount of blood vessels (<5)	No necrosis, moderate hyperemia, and congestion (>5 blood vessels) with high cellularity (dense fibrous and fibrotic)	Necrosis and severe congestion and hyperemia
Odontoblast and odontoblastic cell layer
Absent	Presence of odontoblastic-like cells only	Partial, incomplete palisading cell pattern	Complete palisading cell pattern
Dentine bridge formation:
No hard tissue deposition	Incomplete (partial or thin irregular D. bridge formation)	Thick, regular, and complete dentine associated with hard tissue formation
Bone (calcified bone barrier continuity)
No calcified bone barrier formation (deposition)	Limited calcified bone formation extending to no more than one-half of the exposure site	Partial, incomplete calcified bone formation extending to >1/2 of exposure site but not completely closing the exposure site	Complete calcified bone formation
Periodontal ligament response
	Necrosis disorganized PDL with inflammation	Fully organized PDL with no necrosis and inflammation