Table 2.

Criteria for histopathologic PD Score.

PD Score	Degree	Description
0	Absence	None
1	Slight	Gingivitis: slight hyperplasia of the gingival epithelium, intraepithelial inflammatory cell infiltration. Occasional modest bacterial plaque accumulation. Normal lamina propria, periodontal ligament and alveolar bone.
2	Mild	Periodontitis: gingival hyperplasia and slight migration of junctional epithelium at interdental space. Moderate accumulation of bacterial plaque and hair/food debris. Limited buccolingual extension of lesion. Inflammatory cell infiltration of the gingival epithelium, lamina propria, and periodontal ligament. Mild disruption of periodontal ligament; mild alveolar bone loss.
3	Moderate	Gingival hyperplasia, marked apical migration of junctional epithelium at interdental region. Marked accumulation of bacterial plaque and hair/food debris. Buccolingual extension of lesion. Moderate inflammatory cell infiltration of lamina propria, disruption of periodontal ligament; moderate alveolar bone loss.
4	Severe	Marked apical migration of junctional epithelium with near full root exposure or exposure of bifurcation. Marked accumulation of bacterial plaque and hair/food debris. Marked buccolingual and mesiodistal extension of lesion. Marked inflammatory cell infiltration of lamina propria, disruption of periodontal ligament; severe alveolar bone loss
ONJ		Exposed, necrotic bone; frequent bacterial colonies directly on bone surfaces. Lack of overlying gingival epithelium and lamina propria. Severe destruction of the periodontium, fibrosis and inflammatory cell infiltration of soft oral tissues. One or more fields of 10 or more contiguous empty osteocyte lacunae.