Shibazaki Reiko, Dechow Paul C, Maki Koutaro, Opperman Lynne A
Dallas, Texas; and Tokyo, Japan From the Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Baylor College of Dentistry, Texas A&M Health Science Center, and Department of Orthodontics, Showa University School of Dentistry.
Plast Reconstr Surg. 2007 Jun;119(7):2167-2178. doi: 10.1097/01.prs.0000260705.70329.38.
The role of calvarial sutures in transmitting biomechanical forces within the head is unclear.
To examine the biomechanical characteristics of sutures, the authors measured bite force changes in rats and tested for alterations in strain across intrafrontal and sagittal sutures and within parietal bone with age. To understand the effects of suture fusion on strain distribution in the head, the authors measured percentage fusion of the intrafrontal sutures with age (n = 6 per age group). The masticatory muscles in anesthetized 9-, 24-, and 70-day-old rats (n = 15 per group) were bilaterally stimulated. Stacked delta rosette gauges were fixed across the intrafrontal sutures and sagittal suture, or on the parietal bone. Strain and bite force were measured with a bite force transducer positioned at the incisors.
Bite force increased significantly (p < 0.05) with age (9-day-old rats, 72.6 +/- 20 gf; 24-day-old rats, 707.3 +/- 150 gf; 70-day-old rats, 2425.6 +/- 255 gf). Some significant differences were found between the volume and direction of strain among sites and age groups. Compressive strains of 230 microepsilon on average were found across the intrafrontal sutures at all ages. In contrast, tensile strains less than 180 microepsilon on average were found across the sagittal sutures of 9- and 24-day-old rats, increasing to 940 microepsilon on average at day 70. Tensile strains in parietal bone tended to be less than 150 microepsilon.
The timing of sutural closure and patterns of transsutural strain do not suggest that strain patterns contribute to initial fusion in the intrafrontal sutures. Differences in strain are likely related to changes in rat skull kinetics with growth, perhaps resulting from fusion of the intrafrontal sutures.
颅骨缝线在头部传递生物力学力方面的作用尚不清楚。
为了研究缝线的生物力学特性，作者测量了大鼠的咬合力变化，并测试了随着年龄增长额内缝和矢状缝以及顶骨内应变的改变。为了了解缝线融合对头部应变分布的影响，作者测量了随着年龄增长额内缝的融合百分比（每个年龄组n = 6）。对麻醉后的9日龄、24日龄和70日龄大鼠（每组n = 15）的咀嚼肌进行双侧刺激。将叠加式三角应变片固定在额内缝和矢状缝上，或固定在顶骨上。使用置于门牙处的咬力传感器测量应变和咬合力。
咬合力随年龄显著增加（p < 0.05）（9日龄大鼠，72.6 +/- 20 gf；24日龄大鼠，707.3 +/- 150 gf；70日龄大鼠，2425.6 +/- 255 gf）。在不同部位和年龄组之间，应变的大小和方向存在一些显著差异。在所有年龄段，额内缝平均存在230微应变的压应变。相比之下，9日龄和24日龄大鼠的矢状缝平均存在小于180微应变的拉应变，到70日龄时平均增加到940微应变。顶骨中的拉应变往往小于150微应变。
缝线闭合的时间和跨缝线应变模式并不表明应变模式有助于额内缝的初始融合。应变差异可能与大鼠颅骨动力学随生长的变化有关，可能是由额内缝的融合导致的。
