FIG. 5.

Histopathology on days 5 and 7 after tooth extraction. H&E staining; original magnification × 40. (A, D) Diode group; (B, E) CO₂ group; (C, F) control group. Day 5 postextraction: new bone formation seen from the socket fundus in the diode group and the control group, with a lesser amount in the control group (A, C). In contrast, newly formed immature bone seen extending from the shallow to the middle layer of the extraction socket in the CO₂ group (B). Day 7 postextraction: new bone formation seen from the fundus to the shallow layer of the extraction socket in the diode group and from the shallow to the middle layer with cross-linking pattern in the CO₂ group. Denser cancellous bone is seen in the CO₂ group than in the diode group (D, E). Cancellous bone formation in the extraction socket is immature, weak, and not continuous in the control group (F).