Department of Orthodontics, Texas A&M University, Baylor College of Dentistry, Dallas, TX, USA.
Am J Orthod Dentofacial Orthop. 2013 Aug;144(2):210-7. doi: 10.1016/j.ajodo.2013.03.017.
Suture expansion stimulates bone growth to correct craniofacial deficiencies but has a high potential of treatment relapse. The objective of this study was to investigate whether there is a dose-dependent relationship between the recombinant human bone morphogenetic protein-2 (rhBMP-2) and bone formation during suture expansion.
Fifty 6-week-old male New Zealand white rabbits were randomly assigned to 5 groups to receive 0 (control), 0.01, 0.025, 0.1, or 0.4 mg/mL of rhBMP-2 delivered by absorbable collagen sponge placed over the interfrontal suture. The suture was expanded for 33 days by 200 g of constant force via a spring anchored with 2 miniscrew implants. Distance of suture expansion, suture volume, and cross-sectional area after expansion were measured using radiographs with bone markers and microcomputed tomography. Suture widths and mineralization appositional rates were calculated based on the widths between bone labels under an epifluorescent microscope. Software (Multilevel Win 2.0; University of Bristol, Bristol, United Kingdom) was used to model distance of suture expansion over time as polynomials to compare group differences. Wilcoxon signed rank tests were performed to compare the suture volume and cross-sectional area, mineral apposition rate, and suture width between groups. The significance level was set at P = 0.05.
Whereas the sutures were expanded in all groups, sutures were expanded by significantly greater amounts in the control and the 0.01 mg/mL groups without fusing the sutures than in the 0.025, 0.1, and 0.4 mg/mL groups with fusing sutures. Compared with the controls, the 0.01 mg/mL group showed significantly lower suture volumes, cross-sectional areas, and suture widths after expansion. The mineral apposition rate was significantly higher in the 0.01 mg/mL group than in the controls from days 10 to 30.
The 0.01 mg/mL dose of rhBMP-2 delivered by absorbable collagen sponge can stimulate bone formation at the bony edges of the suture during suture expansion; however, higher concentrations cause suture fusion. With an appropriate concentration, rhBMP-2 might facilitate suture expansion for clinical uses.
缝合扩张刺激骨生长以矫正颅面缺陷，但存在治疗复发的高风险。本研究的目的是探讨重组人骨形态发生蛋白-2（rhBMP-2）与缝合扩张过程中的骨形成之间是否存在剂量依赖性关系。
将 50 只 6 周龄雄性新西兰白兔随机分为 5 组，分别接受 0（对照）、0.01、0.025、0.1 或 0.4 mg/ml 的 rhBMP-2 负载于可吸收胶原海绵上，置于额缝上方。通过用 2 个微型螺钉植入物固定的弹簧以 200 g 的恒力将缝合线扩张 33 天。使用带有骨标记的放射照片和微计算机断层扫描测量缝合线扩张距离、缝合线体积和扩张后的横截面积。基于骨标记下的荧光显微镜下的宽度计算缝合线宽度和矿化附着率。使用软件（Multilevel Win 2.0；英国布里斯托尔大学）将缝合线扩张距离随时间的变化建模为多项式，以比较组间差异。使用 Wilcoxon 符号秩检验比较组间的缝合线体积和横截面积、矿化附着率和缝合线宽度。显著性水平设为 P=0.05。
所有组的缝合线均扩张，但在未融合的对照和 0.01 mg/ml 组中，缝合线扩张量明显大于在融合的 0.025、0.1 和 0.4 mg/ml 组中。与对照组相比，0.01 mg/ml 组扩张后的缝合线体积、横截面积和宽度明显较低。与对照组相比，0.01 mg/ml 组在第 10 天至第 30 天之间的矿化附着率明显较高。
可吸收胶原海绵递送的 0.01 mg/ml 剂量的 rhBMP-2 可在缝合扩张过程中刺激缝合线骨边缘的骨形成；然而，较高浓度会导致缝合线融合。在适当的浓度下，rhBMP-2 可能有助于缝合线扩张，用于临床应用。
