Table 2. Scores used during the histological examination: inflammatory cell response, tissue disorganization, and reactionary dentin formation.

Score	Characterization
	Inflammatory cell response	Tissue disorganization	Reactionary dentin formation
0	None or a few scattered inflammatory cells present in the pulp area corresponding to the buccal surface of the tooth in which the bleaching gel was applied	Normal pulp tissue	Absence
1	Mild inflammatory cell infiltrate with polymorphonuclear or mononuclear leukocytes	Pulp zones (odontoblast, acellular, and cell-rich) disorganization in the buccal surface of the tooth in which the bleaching gel was applied	Modest hard tissue deposition in the coronal pulp of the tooth in which the bleaching gel was applied
2	Moderate inflammatory cell infiltrate	Coronary pulp tissue disorganization with partial local necrosis	Moderate hard tissue deposition in the coronal pulp tissue of the tooth in which the bleaching gel was applied
3	Severe inflammatory cell infiltrate	Intense pulp disorganization with necrosis in the coronal and root pulp tissue	Intense hard tissue deposition in the coronal and root pulp tissue