Bone density and miniscrew stability in orthodontic patients

作者：Samrit Vilas; Kharbanda Om Prakash^*; Duggal Ritu; Seith Ashu; Malhotra Varun

来源：Australian Orthodontic Journal, 2012, 28(2): 204-212.

Objectives: The purpose of this study was to evaluate bone density in buccal inter-radicular bone between second premolars and first permanent molars and its association with the clinical stability of miniscrews used for en masse retraction of anterior teeth in extraction cases.
Materials and Methods: Thirty-eight miniscrews were placed in ten patients (8 females, 2 males: mean age, 18.9 +/- 4.12 years) to provide indirect orthodontic anchorage. Twenty miniscrews were placed in the maxilla and eighteen were inserted in the mandible. All of the miniscrews were placed in the buccal inter-radicular bone between the second premolar and the first permanent molar. Bone density at each miniscrew site was recorded by computed tomography and recorded in Hounsfield units (HU) before miniscrew placement. Nickel-titanium closed-coil springs were used to apply an orthodontic force of 2N within one week following placement.
Results: Cortical bone density values ranged from 506.7 - 1705.6 HU (Mean, 929.27 +/- 322.12 HU) in the maxilla and 503.8 - 1544.8 HU (Mean, 1116.2 +/- 298.33 HU) in the mandible. Cancellous bone density values ranged from 185.9 - 930.8 HU (Mean, 450.09 +/- 205.66 HU) in the maxilla and 197.3 - 803.6 HU (Mean, 561.87 +/- 170.83 HU) in the mandible. There was no statistically significant difference between right and left sides. A bone density comparison between the maxilla and mandible revealed statistically significant higher values in mandibular cortical bone (p = 0.008), while no significant difference was found in cancellous bone values (p = 0.097). Clinically, the success rate of miniscrews in the maxilla was 100% but only 77.8% in the mandible. Miniscrew failures were associated with pen-implant inflammation and miniscrew proximity to dental roots. No relation was found between bone density and miniscrew stability.
Conclusion: The present study determined that no definitive association could be established between miniscrew success and bone density. (Aust Orthod J 2012 28 204-212)

• 出版日期2012-11
• 单位河北医科大学