Department of Orthodontics, Faculty of Dentistry, Bezmialem Vakif University, Istanbul.
Department of Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri.
J Craniofac Surg. 2022;33(1):41-47. doi: 10.1097/SCS.0000000000007837.
To evaluate the effects of 2 different surface roughness values produced by sandblasted, large-grit, and acid-etched treatments at different loading conditions on the stability of mini-screws.
A total of 56 mini-screws (Group 1; 28 with Ra value of 1 μm, Group 2; 28 with Ra value of 1.5 μm) were inserted into the tibia of fourteen New Zealand rabbits. Surface analysis was performed before the placement of the miniscrews using multi-technique characterization. The mini-screws were loaded with 500 grf after different healing times: unloaded, immediate, 4 and 8 weeks. Resonance frequency analyses were performed immediately after mini-screw placement and at the end of loading. Biomechanical and histomorphometric analyses were also performed at the end of the loading period.
All mini-screws preserved their stability at the end of the loading period. However, the resonance frequency analyses showed higher implant stability quotient scores for 8-week group, unlike the immediate loading and unloaded groups (P < 0.05). According to the infinite focus microscopy results, prolongation of healing time resulted in a greater bone area on the loaded mini-screws in Group 2 (P < 0.05). Similarly, the histomorphometric analysis revealed higher bone-to-implant contact values in the 8-week group. There was no significant difference in the stability between the miniscrews with the Ra values of 1 and 1.5 μm.
Sandblasted, large-grit, and acid-etched treated mini-screws showed significantly higher stability with healing time under heavy forces. Sandblasted, large-grit, and acid-etched treated mini-screws can be removed without fracture of the screw or the bone surfaces.
评估喷砂、大粒度酸蚀处理在不同加载条件下产生的两种不同表面粗糙度值对微螺钉稳定性的影响。
将 56 枚微螺钉（组 1：Ra 值为 1μm 的 28 枚，组 2：Ra 值为 1.5μm 的 28 枚）植入 14 只新西兰兔胫骨内。在放置微螺钉之前，使用多技术特征对表面进行分析。微螺钉在不同愈合时间后加载 500 grf：未加载、即刻、4 周和 8 周。在放置微螺钉后立即和加载结束时进行共振频率分析。在加载结束时还进行了生物力学和组织形态计量学分析。
所有微螺钉在加载期末均保持稳定。然而，共振频率分析显示 8 周组的种植体稳定性系数评分较高，与即刻加载组和未加载组不同（P < 0.05）。根据无限远焦点显微镜结果，愈合时间延长导致组 2 加载微螺钉上的骨面积增加（P < 0.05）。同样，组织形态计量学分析显示 8 周组的骨-种植体接触值较高。Ra 值为 1 和 1.5μm 的微螺钉之间的稳定性没有显著差异。
喷砂、大粒度酸蚀处理的微螺钉在高负荷下随愈合时间的延长表现出显著更高的稳定性。喷砂、大粒度酸蚀处理的微螺钉可以在不导致螺钉或骨面断裂的情况下取出。
