Fig. 1From: The role of 25-hydroxyvitamin-D3 and vitamin D receptor gene in human periodontal ligament fibroblasts as response to orthodontic compressive strain: an in vitro studyExperimental design. A Untreated physiological control. A–D No pressure groups (left side). E–H Simulated orthodontic compressive strain of 2 g/cm2 applied by a 17.1 g glass disc (right side). A, E No 25(OH)D3. B, F Treated with 10 ng/ml of 25(OH)D3. C, G Treated with 40 ng/ml of 25(OH)D3. D, H Treated with 60 ng/ml of 25(OH)D3Back to article page