Table 1.

Histological grading according to the cell type and tissue response, adapted from ISO 10993-6.

Response	Score *(phf = per high powered (x400) field)
	0	1	2	3	4
Polymorphonuclear cells	0	Rare, 1–5/phf*	6-10/phf	Heavy infiltrate	Packed
Lymphocytes	0	Rare, 1–5/phf	6-10/phf	Heavy infiltrate	Packed
Plasma cells	0	Rare, 1–5/phf	6-10/phf	Heavy infiltrate	Packed
Macrophages	0	Rare, 1–5/phf	6-10/phf	Heavy infiltrate	Packed
Giant cells	0	Rare, 1–2/phf	3-5/phf	Heavy infiltrate	Packed
Necrosis	0	Minimal	Mild	Moderate	Marked
Fibrinous exudates	0	Minimal	Mild	Moderate	Marked
Tissue degeneration	0	Minimal	Mild	Moderate	Marked
Neovascularization	0	Minimal capillary proliferation focal, 1–3 buds	Groups of 4–7 capillaries with supporting fibroblastic structures	Broad band of capillaries with supporting structures	Extensive band of capillaries with supporting fibroblastic structures
Fibrocytes/fibroconnective tissue, fibrosis	0	Narrow band	Moderately thick band	Thick band	Extensive band
Fatty infiltrate	0	Minimal amount of fat associated with fibrosis	Several layers of fat and fibrosis	Elongated and broad accumulation of fat cells about the implant site	Extensive fat surrounding the implant