Effect of vitamin C on bone formation in the expanded inter-premaxillary suture. Early bone changes

The aim of this experimental study was to histomorphometrically evaluate the effects of vitamin C administration on bone formation in response to expansion of the rat inter-premaxillary suture. A total of 30 50- to 60-day old Wistar male rats were divided into three groups of equal number. The inter-premaxillary suture in each animal was expanded with a 0.49 N force applied to the upper incisors. At 24 h after appliance placement, control animals received saline solution (group I) and two groups were given a single dose of vitamin C using two different methods [locally into the suture (group II) and systemically via intramuscular injection (group III)]. The area of new bone (A mu m(2)), the perimeter around the new bone (A mu m), Feret's diameter (A mu m), and the percentage of new bone to non-ossified tissue (%) were measured and compared. Kruskal-Wallis and Tukey tests were used for statistical evaluation at the p < 0.05 level. We observed significant differences among the groups in all histomorphometric parameters. New bone area, bone perimeter, Feret's diameter, and percentage of new bone dimensions were significantly higher in group III than the others (p < 0.001). Histomorphometric measurements of bone architecture revealed that this improved in the group administered with vitamin C systemically, while local injection revealed significantly less bone growth than the control group. The systemic administration of vitamin C during the early stages of inter-premaxillary suture expansion may stimulate bone growth. However, local injection of this antioxidant into an orthopedically-expanded suture area has negative effects on bone formation.