Abstract: Objective To observe the changes of alveolar bone density in patients with chronic periodontitis before and after oral administration of vitamin D3 by cone beam computed tomography (CBCT). Methods Sixty 50- to 59-year-old patients with chronic periodontitis were selected and took vitamin D3 orally for 12 months. CBCT was used to measure the alveolar bone density at the proximal and distal alveolar septum and the alveolar ridge to the level of alveolar bone in the mesial, distal, buccal and lingual sides of left upper central incisors, canines, and first molars. Whether there was a statistical difference in alveolar bone density was evaluated after the oral administration of vitamin D3. Results There was no statistical significance in the difference of bone mineral density during the first observation after 6 months, but the difference of alveolar bone density during the second observation after 12 months was statistically significant (P＜0.05). Conclusion This study shows that short-term oral administration of vitamin D3 has significant difference in alveolar bone density in patients with chronic periodontitis.

Key words: vitamin D3, CBCT, alveolar bone density, Kron Baja coefficient (Cronbach 's alpha)