Toy Ebubekir, Oztürk Firat, Altindiş Sedat, Kozacioğlu Sümeyye, Toy Hatice
Department of Orthodontics, İnönü University, Malatya, Turkey.
Aust Orthod J. 2014 Nov;30(2):176-83.
Orthodontic maxillary expansion is a commonly-performed treatment approach to correct transverse maxillary deficiencies by separating the mid-palatal suture. To obtain a successful treatment result and prevent relapse, the expanded maxillary sutures require maintenance by means of qualified bone reorganisation.
To assess the effects of low-intensity pulsed ultrasound (LIPUS) on sutural bone formation after the expansion of the interpremaxillary suture in rats.
Sixteen male Wistar rats, 6 to 8-week old, were used. The expansion appliance comprised a helical spring fabricated from 0.014 inch stainless steel wire (Dentaurum, Ispringen, Germany). The rats were divided into two equal groups and randomly assigned to the LIPUS treatment group or a sham-operation group. LIPUS was delivered via a 2.5 cm diameter ultrasound transducer (Exogen, Smith and Nephews, Inc., Memphis, TN, USA) for 20 minutes per day during 7 days of post-expansion retention. Following retention, the rats' maxillae were surgically removed and histologic and immunohistochemical specimens were prepared and examined.
The number of osteoblasts and blood vessel dimensions in the ultrasound group increased but was not significant, compared with the control group. A statistically significant difference in osteocalcin, VEGF and TGF-β immunoreactivities (p < 0.01) was found in the area of the mineralising tissue. Only VEGF immunoreactivity was significant between two groups (p < 0.01) in the fibrous tissue area.
The area of mineralising tissue in the LIPUS-applied group expressed activity markers for osteocalcin, VEGF and TGF-β compared with a surrounding area of fibrous tissue. Cellular activation in the LIPUS group was greater than that of controls. Therefore, LIPUS may be accepted as a useful approach to enhance sutural bone formation.
正畸上颌扩弓是一种常用的治疗方法，通过分离腭中缝来纠正上颌横向发育不足。为了获得成功的治疗效果并防止复发，扩大后的上颌缝需要通过合格的骨组织重建来维持。
评估低强度脉冲超声（LIPUS）对大鼠上颌中缝扩弓后缝间骨形成的影响。
选用16只6至8周龄的雄性Wistar大鼠。扩弓装置由一根用0.014英寸不锈钢丝制成的螺旋弹簧组成（德国登泰克公司，伊斯普林根）。将大鼠分为两组，每组数量相等，随机分为LIPUS治疗组或假手术组。在扩弓保持7天期间，通过直径2.5厘米的超声换能器（美国田纳西州孟菲斯市史赛克公司的外源性超声治疗仪）每天施加LIPUS 20分钟。保持期结束后，手术切除大鼠上颌骨，制备组织学和免疫组织化学标本并进行检查。
与对照组相比，超声组的成骨细胞数量和血管尺寸增加，但差异不显著。在矿化组织区域，骨钙素、血管内皮生长因子（VEGF）和转化生长因子-β（TGF-β）的免疫反应性存在统计学显著差异（p < 0.01）。在纤维组织区域，两组之间只有VEGF免疫反应性存在显著差异（p < 0.01）。
与周围纤维组织区域相比，应用LIPUS组的矿化组织区域表达了骨钙素、VEGF和TGF-β的活性标志物。LIPUS组的细胞活化程度高于对照组。因此，LIPUS可被认为是一种促进缝间骨形成的有用方法。
