槲皮素在大鼠上颌快速扩弓时对腭中缝骨改建的影响

目的：研究槲皮素对大鼠上颌快速扩弓时腭中缝骨质改建的作用。方法：18只6周龄SPF级雄性Wistar大鼠,随机分为3组,A组为空白对照组,B组为扩弓组,C组为扩弓并灌服槲皮素组,每组均6只。其中,A组不扩弓,也不灌服槲皮素;B﹑C组用双眼圈簧扩弓器扩弓,力值0.98 N,C组扩弓后每天灌服槲皮素（100 mg/kg）,A、B组根据体重灌服同剂量的生理盐水。14 d后处死大鼠,标本进行石蜡切片,行常规苏木精-伊红染色、Masson三色染色、免疫组织化学染色。利用Image-pro plus软件对切片吸光度进行分析,采用SPSS 19.0 软件包对数据进行统计学分析。结果：实验第14天,H-E染色和Masson染色显示,A组腭中缝见少量纤维组织,可见软骨细胞、间充质样细胞及成骨细胞等;B﹑C组腭中缝处纤维组织较多,成纤维细胞﹑软骨细胞增多,腭中缝近骨区域处多见成骨细胞;C组成骨细胞数量明显多于B组,有新骨钙化沉积。免疫组织化学染色显示,B组大鼠腭中缝组织中的BMP-2表达量在第14天时显著高于A组（P<0.01）,C 组大鼠腭中缝组织中BMP-2 的表达量显著高于B组（P<0.05）。结论：上颌快速扩弓可扩大生长发育期大鼠的腭中缝;槲皮素能够促进大鼠上颌快速扩弓时腭中缝BMP-2的表达,使骨质沉积钙化,加速新骨形成。     

Update of the classification of midpalatal suture behaviour after surgically assisted rapid maxillary expansion using computed tomography

The aim of this study was to update the midpalatal suture classification after surgically assisted rapid maxillary expansion (SARME) using computed tomography (CT). Thirty-five patients with a transverse maxillary deficiency and unilateral or bilateral posterior crossbite underwent SARME with osteotomy of the pterygoid apophysis of the sphenoid. CT was performed before installation of the Hyrax expander appliance and after the final activation. Opening of the midpalatal suture was classified into three types: type I, total midpalatal suture opening from anterior nasal spine (ANS) to posterior nasal spine (PNS); type II, partial midpalatal suture opening from ANS to the transverse palatine suture, with partial or non-existent opening of the midpalatal suture posterior to the transverse palatine suture; type III, complete maxillary opening from ANS, but not of PNS, because a paramedian fracture completed the opening of the hard palate. Type I was observed in 42.8% of the patients, type II in 40%, and type III in 17.2%. Opening of the transverse palatine suture was found in all midpalatal suture opening patterns and was more frequent in type III, followed by type II and type I. CT was used to update the classification of midpalatal suture patterns, with the inclusion of type III: total opening of the hard palate due partly to opening of the midpalatal suture and partly to a paramedian fracture.     

Influence of differences in the hardness and calcium content of diets on the growth of craniofacial bone in rats

Objective:To examine the effects of a soft diet and a low-calcium diet on the craniofacial growth and bone architectures of the maxilla and mandible.Materials and Methods:Male rats (n  =  20, 3 weeks old) were divided into four groups. Ten rats were given a normal-calcium diet, and the other rats were given a low-calcium diet. Each group was then divided into two subgroups, which were fed a hard or a soft diet. After 4 weeks, craniofacial growth and architecture in maxillary and mandibular bone were analyzed using cephalometry, micro-computed tomography, and histopathology.Results:The low-calcium diet had no effect on serum calcium levels. The low-calcium diet had the greatest effect on craniofacial bone growth, while the soft diet affected the growth of several bone sites that are attached to the masseter muscle. A low-calcium diet resulted in the deterioration of the connectivity of the trabeculae in the furcation region of the maxillary and mandibular first molar, while a soft diet resulted in the diffuse disappearance of trabeculae in the central part of the furcation regions. In the midpalatal suture, a low-calcium diet resulted in inhibition of cartilaginous ossification, although the midpalatal suture had a normal cartilaginous structure. A soft diet resulted in narrower cartilage cell layers in the midpalatal suture.Conclusions:We demonstrated that a low-calcium diet and a soft diet resulted in a deterioration of bone structures in both the maxilla and in the mandible; however, the mechanisms underlying these effects differed between diets.     

Evaluation of craniofacial effects during rapid maxillary expansion through combined in vivo/in vitro and finite element studies

It is well documented in the literature that a contracted maxilla is commonly associated with nasal obstruction. Midpalatal splitting using the rapid maxillary expansion (RME) technique produces separation of the maxillary halves with consequent widening of the nasal cavity. Although clinicians agree about many of the indications for and outcomes of RME, some disagreements persist in relation to the biomechanical effects induced. The present research was based on the parametric analysis of a finite element model (FEM) of a dry human skull with the RME appliance cemented in place in order to evaluate these effects on the overall craniofacial complex with different suture ossification. The behaviour of the FEM was compared with the findings of a clinical study and to an in vitro experiment of the same dry skull. Comparisons refer to the opening pattern and associated displacements of four anatomical points located at the left and right maxilla (MI, UM, EM, CN). It was found that the maxillolacrymal, the frontomaxillary, the nasomaxillary, the transverse midpalatal sutures, and the suture between the maxilla and pterygoid process of the sphenoid bone did not influence the outcome of RME, while the zygomatico-maxillary suture influenced the response of the craniofacial complex to the expansion forces. Moreover, the sagittal suture at the level of the frontal part of the midpalatal suture plays an important role in the degree and manner of maxillary separation. Maximum displacements were observed in the area of maxilla below the hard palate, from the central incisors to second premolars, which dissipated at the frontal and parietal bone and nullified at the occipital bone.     

锥形束CT测量不同矢状骨面型青少年腭部骨厚度

目的：研究锥形束CT（CBCT）测量青少年患者腭部不同区域骨厚度的差异,分析在腭部相同区域中Ⅰ、Ⅱ、Ⅲ类矢状骨面型青少年患者骨厚度的差异,为临床腭种植支抗的植入提供参考。方法选取90例垂直骨面型为均角的12～16岁青少年患者,依照矢状骨面型分为Ⅰ、Ⅱ、Ⅲ类三组,每组男女各15例,进行CBCT扫描。以切牙孔后缘与后鼻棘点连线作为水平基准平面,在切牙孔后4.0、8.0、12.0、16.0、20.0、24.0 mm冠状向截面上,距腭中线0.0、2.0、4.0、6.0 mm矢状向截面上,测量两基准线的24个交点的垂直骨厚度。结果（1）腭部骨厚度在腭中缝处由前往后逐渐增加,在腭侧区及腭旁区由前往后逐渐减少（P＜0.05）;（2）腭部骨厚度在前份区域从腭中缝往两侧逐渐增加,在中份及后份区域由腭中缝往两侧逐渐减少（P＜0.05）;（3）在腭部的相同区域中,不同矢状骨面型青少年患者腭部骨厚度差异有统计学意义（P＜0.05）。在腭中缝前份、腭中缝中份、腭中缝后份、腭侧区前份、腭旁区前份区域中,Ⅰ、Ⅱ类青少年患者腭部骨厚度大于Ⅲ类青少年患者;腭侧区中份、腭侧区后份、腭旁区中份、腭旁区后份区域中,仅Ⅱ类青少年患者腭部骨厚度大于Ⅲ类青少年患者。结论（1）腭部微种植支抗的最佳植入部位为腭旁区前份;（2）在相同腭部植入区域中,Ⅲ类青少年患者骨厚度小,穿通鼻底风险更大,建议Ⅲ类青少年患者选择更短的腭种植支抗。     

Bone marrow mesenchymal stem cells enhance bone formation in orthodontically expanded maxillae in rats

Objective:To transplant bone marrow–derived mesenchymal stem cells (MSCs) into the interpremaxillary suture after rapid maxillary expansion with the aim of increasing new bone formation in the suture.Materials and Methods:Nineteen male Wistar rats were divided into two groups (control, n  =  9; experimental, n  =  10). Both groups were subjected to expansion for 5 days, and 50 cN of force was applied to the maxillary incisors with a helical spring. Pkh67⁺ (green fluorescent dye)–labeled MSCs were applied to the interpremaxillary suture after force application into the interpremaxillary suture of rats. Bone formation in the sutural area was histomorphometrically evaluated, including the amount of new bone formation (µm²), number of osteoblasts, number of osteoclasts, and number of vessels. Mann-Whitney U-test was used for statistical evaluation at the P < .05 level.Results:After 10 days of retention, Pkh67⁺ can be detected in suture mostly in the injection site under fluorescence microscope. Histomorphometric analysis revealed that a single local injection of MSCs into the midpalatal suture increased the new bone formation in the suture by increasing the number of osteoblasts and new vessel formation, compared with controls injected with phosphate-buffered saline.Conclusions:This preclinical study might provide foundations for the underlying potential clinical use of MSCs after maxillary expansion. Given the fact that MSCs are currently in use in clinical trials, this approach might be a feasible treatment strategy to accelerate new bone tissue formation in midpalatal suture and to shorten the treatment period for patients undergoing maxillary expansion reinforcement     

Healing of maxillary alveolus in transport distraction osteogenesis for partial maxillectomy.

PURPOSE: This study aims to evaluate histologic healing of the new bone and soft tissue in the distraction gap of maxillary alveolus after transport distraction at different consolidation intervals. MATERIALS AND METHODS: In a monkey model, dentoalveolar segment was distracted backward to a surgical defect in the posterior maxilla with an internal distractor at a rate of 1 mm/day for 2 weeks. The distracted dentoalveolar processes were harvested at 1, 2, and 3 months of consolidation after the completion of distraction. Histologic examination included the new bone, gingiva of the distraction gap, and teeth carrying the transport segments. Tartrate-resistant acid phosphatase was used to assess the presence of osteoclasts in the new bone. The collagen type and expression of bone morphogenetic proteins (BMPs) in the new bone were assessed by immunohistochemistry. RESULTS: The histology confirmed new bone bridging the distraction gap at 1 month of consolidation. Woven bone was progressively replaced by mature lamellar bone at the second and third months. The gingiva covering the distraction gap was of normal appearance. There were no pathologic pulpal changes noted in the transport segment. Tartrate-resistant acid phosphatase-positive osteoclasts were minimal in the new bone. The mode of ossification was confirmed as intramembranous, and the fibrous stroma consisted mainly of collagen type I. At 1 month of consolidation, the BMPs were expressed profusely in the fibrous matrix and also inside the fibroblasts and osteoblasts. At 2 and 3 months of consolidation, the BMP expression intensity was reduced significantly in the fibrous stroma. CONCLUSIONS: The study confirmed that the bone regenerate in maxillary transport distraction was formed by intramembranous ossification and teeth in the transport segment remain viable after maxillary transport distraction osteogenesis.     

Evaluation of opening pattern and bone neoformation at median palatal suture area in patients submitted to surgically assisted rapid maxillary expansion (SARME) through cone beam computed tomography

Surgically assisted rapid maxillary expansion (SARME) is the treatment of choice to adult patients even with severe transversal maxillary discrepancies. However, the adequate retention period to achieve the bone remodeling, thus assuring treatment stability, is controversial.

Objective

To evaluate the opening pattern and bone neoformation process at the midpalatal suture in patients submitted to surgically assisted (SARME) through cone beam computed tomography (CBCT).

Material and Methods

Fourteen patients were submitted to SARME through subtotal Le Fort I osteotomy. Both the opening pattern and the mean bone density at midpalatal suture area to evaluate bone formation were assessed pre- and post-operatively (15, 60 and 180 days) through CBCT.

Results

Type I opening pattern (from anterior to posterior nasal spine) occurred in 12 subjects while type II opening pattern (from anterior nasal spine to transverse palatine suture) occurred in 2 individuals. The 180-day postoperative mean (PO 180) of bone density value was 49.9% of the preoperative mean (Pre) value.

Conclusions

The opening pattern of midpalatal suture is more related to patients’ age (23.9 years in type I and 33.5 years in type II) and surgical technique. It was not possible to observe complete bone formation at midpalatal suture area at the ending of the retention period studied (180 days).     

上颌快速扩大兔腭中缝组织改建的连续组织学研究

目的研究上颌快速扩大腭中缝牵张成骨的连续过程及规律，了解快速扩张腭中缝的缝组织反应和组织再生机理。方法选用处于生长期新西兰大白兔52只，随机分为13组，实验组5组、对照组6组，荧光标记的实验组和对照组各1组。采用螺旋分裂基托扩大矫治器（Haas矫正器）扩张兔上牙弓，快速扩张期2周，固定期4周。扩张速率为0．25mm／12h，共扩张牵引14天，分别于即刻、第7、14、21、28、42天取材，标本常规进行组织学观察。并利用激光共聚焦扫描显微镜及荧光标记观察快速扩张腭中缝成骨活动的情况。结果快速扩张2周后可见腭中缝明显增宽，可见创伤性反应，成骨和成纤维细胞大量增殖，大量胶原纤维沿扩张力方向有序排列，成骨活动沿骨缝边缘平行沉积。快速扩张的腭中缝有强烈的血管生成反应，新生骨组织改建活跃，直至新的骨缘形成。缝恢复正常的形态。荧光标记观察实验组骨沉积带明显宽于对照组。结论扩张的腭中缝新骨改建主要发生在腭中缝骨缘。腭中缝改建的过程是纤维修复和骨组织再生过程。     

Surgically assisted rapid maxillary expansion by opening the midpalatal suture

The results of surgically assisted rapid maxillary expansion by opening of the midpalatal suture in 25 patients are reported. Osteotomy of the lateral wall of the maxilla combined with pterygomaxillary dysjunction and midpalatal suture separation allowed for successful rapid maxillary expansion in 23 patients. The two patients who did not respond to treatment were found to have unusually thick midpalatal sutures, which were successfully expanded after the midpalatal sutures were osteotomized.     

Impact of rapid maxillary expansion in unilateral cleft lip and palate patients after secondary alveolar bone grafting: review and case report

The purpose of this article was to analyze the effects and short-term stability of rapid maxillary expansion performed after secondary alveolar bone grafting in unilateral cleft lip and palate (UCLP) patients. Two UCLP patients with severe maxillary constriction who had previous bone grafting were involved in this study. A hyrax rapid expansion appliance was placed on 4 abutment teeth and activated twice daily. An opening of the midpalatal suture was found on the posttreatment occlusal radiographs, which was clinically confirmed by the diastema. Posteroanterior cephalometric tracing analysis demonstrated significant increases in maxillary and dental arch width. No obvious radiographic alteration was observed in the grafted areas.     

Anatomic site evaluation of the palatal bone for temporary orthodontic anchorage devices

Objectives: The aim of the present study was to assess the micromorphologic characteristics of the palatal bone from an implantologic standpoint.
Materials and Methods: The material consisted of tissue blocks of autopsy material from 22 subjects (18 males, three females) between 18 and 63 years of age. The specimens comprised the anterior median palatal region from 5 to 10 mm behind the incisive foramen. They were prepared in the transversal plane according to ground thin-section technology. The midpalatal area as well as an area of 3 mm bilateral to the midline were assessed, and a classification of quantitative palatal bone availability was developed.
Results: The findings could be divided into three classes: (1) class I palatal bone consists almost of compact bone; (2) class II cortical bone layer on oral and nasal sides of palate, broad compact bone in the suture area (≥3 mm), loose trabecular bone lateral to the suture area; and (3) class III cortical bone on oral and nasal side, thin compact bone in the suture area (<3 mm) and loose-structured trabecular bone lateral to the suture area. In most sections (72.7%), class I characteristics were found (16 subjects). 18.2% of sections were assigned to class II (four subjects) and only 9.1% of sections were assigned to class III (two subjects).
Conclusion: These results document that in most cases a good primary stability of temporary orthodontic anchorage devices should be achieved in the midpalatal and paramedian area of the anterior palate, as the bone quantity available is high.     

Immunohistochemical identification of TGF-beta1 at the maxillaries in growing Sprague-Dawley rats and after muscle section

Growth factors are currently being extensively studied in the literature to ascertain their role during maxillofacial development. Taking into account that few investigations refer to the functions of growth in the maxillaries, our aim was to identify the TGF-beta1 immunohistochemical expression pattern in the maxillaries of growing rats. A secondary aim was to identify this pattern after orofacial function inhibition by muscle section. In the palate and the mandibular symphysis and body, we found that bone was formed through an endomembranous pathway with intense TGF-beta1 staining inside chondroid cells during the maximum development stages. At the midpalatal suture and the mandibular symphysis and condyle, endochondral ossification was detected with an intense expression of TGF-beta1 inside the chondrocytes when major growth occurred. After the muscle had been sectioned, at the mandible the maturation process was accelerated, this change being transitory until muscular function was recovered. However, at the palate, the intervention caused a greater disturbance of the growing pattern, which did not recover normality.     

Ossification of the midpalatal suture after surgically assisted rapid maxillary expansion

The purpose of this study was to evaluate ossification of the midpalatal suture in adult patients immediately after surgically assisted rapid maxillary expansion (SARME) until 120 days post-surgery. The sample comprised 126 standardized occlusal radiographs of 21 adults (14 females and 7 males; mean age: 25.33 years) taken pre-expansion (T1), immediately after expansion (T2), and post-expansion (30, 60, 90, and 120 days of retention, respectively: T3, T4, T5, and T6) who had undergone SARME. The radiographs were digitized and the images were analysed and compared in relation to the morphology and radiopacity at the different treatment stages, especially concerning the characteristics of the midpalatal suture. Data were statistically analysed using analysis of variance and Tukey's test. The results demonstrated that from T2 to T6, the mean optical density (OD) increased. However, these values were not similar to those observed at T1. A retention period of 120 days was not sufficient for the re-establishment of OD and complete ossification within the suture in the evaluated patients.     

BMP-2和OPG在腭横缝牵引中的表达

目的：了解腭横缝牵张成骨中骨形成蛋白2（BMP-2）和护骨素（OPG）的表达，探讨持续牵引力对骨改建的调控过程。方法：以杂种犬16只为实验动物，实验组在腭横缝及额上颌缝安置内置式镍钛合金牵引器。空白对照组不处理。术后10、20、30、40d切取腭横缝组织，行组织学观察。结果：实验组上颌骨成功前移，BMP-2、OPG阳性染色主要定位于成骨细胞中。结论：缝牵引可以顺利扩张生长期上颌骨，其成骨方式是膜内成骨；BMP-2可以诱导和激发成骨细胞活性，OPG在骨吸收过程中起重要调控作用。     

扩张力作用下大鼠腭中缝组织成骨现象的连续观察

目的：观察扩张力作用下大鼠腭中缝牵张成骨的组织形态学变化及新骨形成情况,探讨扩弓后腭中缝组织的反应和新骨形成方式。方法：选用4周龄健康雄性wistar大鼠55只,随机分为实验组5组、对照组6组,采用两眼簧后牙扩弓器扩张大鼠上颌腭中缝组织,分别于0d、实验1、2、4、7、11d取材,标本常规进行石蜡切片,行常规苏木精-伊红染色、Masson三色染色、骨钙素（OCN）免疫组化。结果：扩张1d后即可见腭中缝明显增宽,并可见成骨细胞的分化和成纤维细胞的增殖;扩张2d和4d后可见软骨细胞带外侧有新骨沉积;固定3d后可见骨缝边缘内外侧均有新骨沉积;固定7d后,可见两侧陈旧的软骨细胞带内侧有大量类骨质形成,两侧骨缘呈指状嵌合。结论：扩张的腭中缝新骨改建主要发生在腭中缝骨缘,并由软骨内成骨的方式向膜内成骨方式进行转变。     

上颌快速扩弓腭中缝血管内皮生长因子的时空表达与新骨形成的相关性研究

目的 探讨上颌快速扩弓扩张期和固定期兔腭中缝组织血管内皮生长因子（VEGF）的时空表达模式以及新骨形成情况。方法 将44只新西兰大白兔随机分为11组：实验组（共5组）、对照组（共5组）、对照0组,每组4只。用螺旋分裂基托扩大矫治器（Haas矫正器）扩张兔上牙弓,快速扩张2周,固定4周。在安装扩张器当天（对照0组）、快速扩张第1、2周、固定第1、2、4周（实验组和对照组）取兔上颌骨腭中缝组织块,采用免疫组织化学法检测VEGF在腭中缝组织中的分布和表达变化,采用过碘酸-Schiff染色法观测新骨形成。结果 快速扩张的腭中缝可见高水平的VEGF表达,VEGF阳性信号主要定位于血管内皮细胞胞浆和增殖活跃的成骨细胞胞浆。对照组VEGF在整个实验过程中均呈弱阳性表达。实验组快速扩张第1周、快速扩张第2周、固定第1周、固定第2周VEGF蛋白表达量均高于对照组。随着机械应力快速扩张,实验组VEGF蛋白表达量逐渐上升,固定1周达峰值后逐渐下降。实验组新骨形成的量均高于对照组,新骨形成的量逐渐上升,固定2周达峰值后逐渐下降。结论 上颌快速扩弓产生的机械牵张力可以导致VEGF生成增加从而促进血管及新骨的生成。     

Three-dimensional finite-element analysis of maxillary protraction with and without rapid palatal expansion

The aims of this study were to determine the reaction of the craniofacial bones on the protraction force transferred to the maxillary body, and whether or not the midpalatal suture had opened during skeletal Class III treatment. A computerized tomograph was obtained from a dry skull with a normal occlusion to construct a three-dimensional finite-element model (3D.FEM) of the craniofacial bones and the maxillary teeth to simulate actual bone reactions. A protraction force of 500 g was applied at the first premolar region, directed 20 degrees inferior to the occlusal plane. The displacement and the stress distribution of the craniofacial bones and sutures were then calculated using the ANSYS 5.3 program dividing the analysis into two simulations, based on whether or not the midpalatal suture was opened. The results showed that there was less compressive stress and greater tensile stress in the circumaxillary suture areas when the midpalatal suture was opened. The amount of displacement and deformation when the midpalatal suture was opened also demonstrated a decrease in upward-forward rotation of the maxilla and zygomatic arch and greater amounts of displacement in the frontal, vertical, and lateral directions compared with no opening of the midpalatal suture. Analysis of these results showed that maxillary protraction produce similar changes to normal downward and forward growth of the maxilla and was achieved with accompanying opening of the midpalatal suture.     

Surgical and orthodontic rapid palatal expansion in adults using Glassman's technique: retrospective study

In 1984, Glassman et al. described a conservative surgical method of separation of the midpalatal suture in which an osteotomy is done only at the lateral and anterior wall of the maxilla. Between 1991 and 1997, we have operated on 21 patients with maxillary transverse discrepancies using the method that they described. This gave good results in 20 patients. The other, who was operated on at the age of 38 years, developed a fracture of the alveolar process of the maxilla on one side because of ossification of the midpalatal suture. The surgically assisted rapid palatal expansion described by Glassman et al. is suitable for patients up to the age of 30. Older patients require additional surgical separation of the midpalatal suture.