Background: The present study was conducted to assess effect of orthodontic forces on pulp tissues. Materials & Methods: The present study was conducted on 48 patients required maxillary first premolar extraction for orthodontic purposes. A cantilever spring made of 16 × 22 steel wire was used to apply intrusive force to upper first premolars (Group I) and the opposing teeth were considered as control group (Group II). Histologic changes were compared between the control and intrusive groups after 7 days and 1 month. Results: Inflammation at 7 days in group I was none seen in 66% and mild in 34% 34% and in group II was none seen in 84% and mild in 16%. At 1 month was none seen in 100% in both groups. Fibrous tissue at 7 days was none seen in 100% teeth in both groups and at 1 month was none seen in 40% in group I and 100% in group II and mild in 60% in group II. Vascular dilatation at 7 days was none seen in 65% and moderate in 35% in group I and none in 60% and moderate in 40% in group II. Vascular dilatation at 1 month was none in 60% and mild in 40% in both groups. The difference was significant (P< 0.05). Conclusion: Mild intrusive force in closed apex teeth causes no significant histologic changes in both groups. Key words: Intrusive force, Orthodontic, Pulp