种植钉辅助扩弓后腭中缝断裂的有限元模型建立

目的用三维有限元方法分析扩弓时上颌复合体应力蓄积至腭中缝完全断裂过程的力学特点,并验证模型有效性。方法建立包含种植钉的上颌复合体有限元模型。设定腭中缝屈服强度,以每5 ms加载0.25 mm水平横向位移为载荷,加载至腭中缝完全断裂,同时以临床1例种植钉辅助扩弓患者扩弓前后CT影像结果进行对比验证。结果 0～17 ms,腭中缝应力主要蓄积于腭骨水平板、种植钉周围、腭中缝中后方及颧颌缝; 18～60 ms,腭中缝中后部出现裂纹并向前后扩展; 61～71 ms,腭中缝中后部、前部、后部依次发生断裂。结论基于断裂力学的种植钉辅助扩弓的三维有限元模型有效,其计算的断裂过程结果更符合临床实际。研究结果为今后更有效研究种植钉辅助扩弓提供力学参考模型。     

Variations of the prominences of the bony palate and their relationship to complete dentures in Korean skulls.

The osteological and morphological variations of the prominences in the bony palate of 160 Korean skulls were studied. The frequency of the occurrence of the posterior palatine crest, located on the posterior border of the greater palatine foramen, was 13.8%. Palatal ridges were observed commonly in the skulls; however, the smooth type, which has no palatal ridges in the palate, was shown in 14.7% of cases, and palatal spines were observed in 33.8%. The prevalence of palatal tubercles was 11.6%, and all were found in the molar region. The palatine torus was found in 18.8% of cases and the most common type was along the median palatine suture from the incisive foramen to the posterior border of the palatine bone (63.3%). No significant differences between sexes or sides were found in the posterior palatine crest, palatal ridges, and palatal tubercle. However, the sex distribution of the palatine torus was significantly different (P < 0.05). These results would be helpful clinically in fabricating maxillary complete dentures for edentulous patients.     

Width and elevation of the palatal shelves in unoperated unilateral and bilateral cleft lip and palate patients in the permanent dentition

Patients with cleft left lip and palate (CLP) normally require extensive surgery from an early age up to the end of adolescence. These surgeries affect the growth of the maxillofacial complex. The degree to which the cleft itself affects growth of the maxillofacial complex remains poorly understood. By analysing the width and elevation of the palatal shelves in unoperated adolescents and adults with unilateral and bilateral cleft lip and palate (UCLP and BCLP, respectively) and a non-cleft control group, it is possible to gain more insight into the real intrinsic growth potential of the maxillary structures. In this study, dental casts of the full permanent dentition of individuals with unrepaired UCLP (n = 68) and BCLP (n = 13) and non-cleft controls (n = 24) from the same area of Indonesia were digitized three-dimensionally. Maxillary arch width in the canine, premolar and molar regions, and the width and elevation of the palatal shelves were measured. Results showed that in patients with UCLP, the width of the palatal shelves on the cleft side in all regions, and on the non-cleft side in the canine/first premolar region, was significantly smaller compared with the control group. BCLP subjects showed similar deviations. In the UCLP group, the palatal shelves were rotated cranially and positioned more vertically. In the BCLP group, the palatal shelves were inclined by almost 10 ° more than the control group. The width of the palatal shelf and width of the maxillary arch positively correlated in the canine and first premolar regions for both the cleft and non-cleft side in patients with UCLP, and in the canine region for patients with BCLP. This means that the wider the palatal shelf, the wider the maxillary arch. The elevation of palatal shelves correlated with the maxillary arch width in all regions in patients with UCLP, and only in the premolar region in the control group. Thus, the wider the arch width, the smaller the elevation angle (the maxillary shelves are less vertical). No correlations between palatal shelf elevation and maxillary arch width were found in the BCLP group. This shows that the intrinsic growth potential in patients with UCLP and BCLP is affected by a smaller palatal shelf width and larger elevation of the shelves. These deviations may result in a wider cleft.     

Jag2-Notch1 signaling regulates oral epithelial differentiation and palate development.

During mammalian palatogenesis, palatal shelves initially grow vertically from the medial sides of the paired maxillary processes flanking the developing tongue and subsequently elevate and fuse with each other above the tongue to form the intact secondary palate. Pathological palate-mandible or palate-tongue fusions have been reported in humans and other mammals, but the molecular and cellular mechanisms that prevent such aberrant adhesions during normal palate development are unknown. We previously reported that mice deficient in Jag2, which encodes a cell surface ligand for the Notch family receptors, have cleft palate associated with palate-tongue fusions. In this report, we show that Jag2 is expressed throughout the oral epithelium and is required for Notch1 activation during oral epithelial differentiation. We show that Notch1 is normally highly activated in the differentiating oral periderm cells covering the developing tongue and the lateral oral surfaces of the mandibular and maxillary processes during palate development. Oral periderm activation of Notch1 is significantly attenuated during palate development in the Jag2 mutants. Further molecular and ultrastructural analyses indicate that oral epithelial organization and periderm differentiation are disrupted in the Jag2 mutants. Moreover, we show that the Jag2 mutant tongue fused to wild-type palatal shelves in recombinant explant cultures. These data indicate that Jag2-Notch1 signaling is spatiotemporally regulated in the oral epithelia during palate development to prevent premature palatal shelf adhesion to other oral tissues and to facilitate normal adhesion between the elevated palatal shelves.     

上腭发生的分子调控机制

哺乳动物上腭的发生包括原生腭和次生腭的发生.其中,次生腭的发生涉及到高度动态的形态发生过程,分为腭突生长及模式化,两侧腭突的上抬/重定位,两侧腭突的黏附和融合形成次生腭等过程.近来的研究表明,上腭发育所需的基因,包括了声波刺猬蛋白(Shh)、成纤维细胞生长因子(FGF)、转化生长因子β(TGF-β)和Wnt信号通路,这...     

上颌骨性扩弓器在上颌骨横向发育不足中的应用及优势

文题释义： 上颌骨横向发育不足：是许多错牙合畸形的常见伴发症状，青少年发病率为8%-23%，成人正畸患者发病率约为10%，常表现为上颌基骨及牙弓狭窄、腭盖高拱、单侧或双侧后牙反或对刃、颊廊过大等。 上颌骨性扩弓器：通过4颗穿透双层骨皮质(腭骨和鼻底)的微种植体的辅助，将特制的螺旋扩弓器固定在硬腭后部，使螺旋扩弓器产生的扩弓力直接作用于上颌骨而不是牙列，从而产生骨性扩弓效应。 背景：上颌骨性扩弓器是一项上颌骨非手术扩弓技术，与传统的上颌快速扩弓器、微种植体辅助上颌快速扩弓和外科手术辅助上颌快速扩弓截然不同，为上颌骨横向发育不足的矫治提供了新思路、新方法，尤其为生长发育完成的成年患者提供了高效且微创的骨性扩弓效果。 目的：通过检索、筛选和阅读大量文献的方法，对上颌骨性扩弓器在上颌骨横向发育不足中的应用及优势进行系统性综述，为该类患者临床治疗方案确定提供科学的参考依据。 方法：对Cochrane图书馆、PubMed、Embase、Web of Science、中国学术期刊全文数据库(CNKI)、万方数据库(Wanfang)、中国生物医学文献数据库(CBM)等国内外常用数据库进行计算机检索，全面收集2019-05-31之前发表的与上颌骨性扩弓器相关的中英文文献。 结果与结论：上颌骨性扩弓器是矫治上颌骨横向发育不足的一种有效方法，其扩弓不受年龄限制，对于成人依然有良好的骨性扩弓效果。上颌骨性扩弓器使整个面中部结构扩张，导致腭中缝接近平行扩大，翼腭缝裂开，颧骨间宽度增加，包括鼻骨上区在内的整个鼻腔变宽，且牙齿颊倾、牙槽骨高度降低等不良反应较小。 ORCID: 0000-0001-7741-6045(张肖雅) 中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程     

Radiographic and microscopic anatomy of the mid-palatal suture in the elderly

In a previous radiological study of the mid-palatal suture, it has been demonstrated that its obliteration was occurring during adult life and varied. In order to determine the histological status of mid-palatal suture in elderly men, 20 human palates aged more than 70 were examined by occlusal radiographs and histological study of the suture. In all palates the suture was ossified in the anterior thirds and made of conjunctive tissue in the posterior third. This particular evolution could be correlated to the mastication forces acting on the maxillary bones during the entire life.     

Histochemical localization of glycosaminoglycans during morphogenesis of the secondary palate in mice

Summary The hydration of hyaluronic acid (HA) accumulated in the secondary palatal processes is expected to exert an intrinsic tissue pressure that could, in part, provide the impetus for shelf reorientation. Glycosaminoglycans were histochemically localized in the A/J mouse palate during development (days 12 to 15) by specific enzymatic degradation followed by preferential staining with alcian blue under differential pH or MgCl₂ concentration. The presence of HA and chondroitin sulphates A and C (CS) was demonstrated in proportions that differed regionally. At the time of reorientation (days 14 to 15) HA was the predominant staining component, being distributed according to the relative prominence of extracellular spaces (ECS). HA was present in higher concentration in the anterior than the posterior part of the palate, particularly in an area of low cell density adjoining the CS-rich mesenchyme of the maxillary process. This arrangement suggests that the maxillary process might provide a resilient incompressible structural base for the palate as its HA-rich ECS expands. Sulphated GAG, with CS being the predominent component, was localized for the most part on the oral-side mesenchyme both in the anterior and posterior palate. The most intense staining of sulphated proteoglycans occurred in association with the basal lamina along the presumptive oral-side. Mesenchymal cells along this region appeared condensed and may have been stabilized by these sulphated GAG providing structural constraints which might function in palate morphogenesis.     

The nasopalatine ducts and associated structures in the rhesus monkey (Macaca mulatta): Topography,prenatal development,function, and phylogeny

Morphological and developmental characteristics of the rhesus monkey nasopalatine duct system and associated primary palatal structures are described along with functional and phylogenetic considerations. Examination of five adult palates and coronal sections of 13 fetal palates together with dissections of a sixth adult specimen and of a 119-day-old fetal palate reveal that the lateral lobes of the tripartate incisive papilla cover clefts leading into the ducts. The ducts pierce the bony palate to enter the nasal fossae in proximity to the incisive suture. The ontogenetic stability of the duct path reflects the retention of ancient duct and primitive choanae relationships and functionally maintains an optimal oral odorant-to-receptor channel. Sixteen timed pregnancy specimens (35–100 days) provided histological material for documenting rostral nasopalatal development. Duct primordia, identified at 35 days, had by 40 days formed the medial duct walls (conjoined septum-papilla from the primary medial palatal component), the lateral duct walls (maxillary processes), and the rostral walls (fused maxillary-intermaxillary components). The caudal walls derive from the fusion of palatal shelves with the papilla (45 days), thus distinguishing primary and secondary fusion modes. Duct epithelial maturation occurs between 70 and 100 days. The absence of a vomeronasal system is attributed to reduction of olfaction in reproductive behavior, while the presence of the coevolved nasopalatine ducts is linked to the persistence of epiglottal-velar valving. The ducts serve as oral food-odor conduits in otherwise functionally separated respiratory and digestive tracts.     

Analysis of Meox-2 mutant mice reveals a novel postfusion-based cleft palate.

Cleft palate represents a common human congential disease involving defects in the development of the secondary palate. Major steps in mammalian palatogenesis include vertical growth, elevation, and fusion of the palate shelves. Our current study with the homeobox gene Meox-2 during mouse secondary palate development reveals a novel postfusion-based mechanism for cleft palate. Meox-1 and Meox-2 are two functionally related homeobox genes playing important roles in somitogenesis and limb muscle differentiation. We found that the expression of Meox-2, not Meox-1, marks the specification of early mouse palatal mesenchymal cells in the maxillary processes at embryonic day 11.5 (E11.5). From E12.5 to E15.5, the expression of Meox-2 occupies only the posterior part of the palate, providing an early molecular marker for the anterior-posterior polarity in mouse secondary palate formation. A total of 35.3% of Meox-2-/- (n = 17) and 25.5% of Meox-2+/- (n = 55) mouse embryos display a cleft palate phenotype at E15.5, indicating that the reduction of Meox-2 function is associated with susceptibility to cleft palate. Unlike previously reported clefts, none of the clefts found in Meox-2 mutants contain any epithelial sheets in the medial edge areas, and detailed examination revealed that the clefts resulted from the breakdown of newly fused palates. This article is the first report of a gene required to maintain adherence of the palatal shelves after fusion.     

Palate structure in human holoprosencephaly correlates with the facial malformation and demonstrates a new palatal developmental field

In this study we analyzed palate structure in holoprosencephaly and correlated it with the facial malformations. Eleven human holoprosencephalic fetuses (three cyclopic, two ethmocephalic, one cebocephalic, four with median cleft lip, and one with short philtrum) at 17–23 weeks of gestation and three children (age 2½, 6 and 7 years) with a single central incisor were studied. Photographic and radiographic methods were used. We found that in holoprosencephaly palate structure is abnormal. The severity of this malformation decreases with decreasing severity of facial malformation. Thus, the study shows a close relationship between the facial and the palatal malformation. In all phenotypes the premaxillary area is malformed. From this region, a fan-shaped field along the midpalatal suture is involved in all facial phenotypes, the fan being broadest in cyclopia and narrowest in the short philtrum malformation. A similar fan-shaped field can be discerned in the face, where the broadest fan also indicates the greatest severity with cyclopia, and the narrowest fan the least severe median lip malformation. In the palate field, the anteroposterior furrows seemingly demarcate the field. The findings may be of importance for the future evaluation of palatal malformations in children. Am. J. Med. Genet. 73:387–392, 1997. © 1997 Wiley-Liss, Inc.     

The pathology of the velopharyngeal musculature in cleft palates.

AIMS: This article draws attention to a pathological finding in the cleft palate condition that has not been previously described: It is demonstrated that the palatal aponeurosis exists even in cleft palates, but it is disrupted, malpositioned and folded in 2 layers. It is possible to dissect the 2 layers and to unfold the aponeurosis to form a tough tendinous plane. Thus, the retropositioning of the levator veli palatini muscle sling is facilitated. CONCLUSION: For a normal reconstruction of the cleft palate it is not only necessary to reconstruct the levator veli palatini muscle sling but also to approximate and to suture the fibres of the palatal aponeurosis to the corresponding fibres of the opposite side after unfolding them in a mediodorso-cranial direction. In this manner a continuous palatal aponeurosis can be created and subsequently it can serve as a transmitter of the muscle forces.     

比格犬上颌窦的应用解剖

目的探讨比格犬上颌窦正常解剖,为与上颌窦有关的动物实验提供解剖学依据。方法收集16个比格犬上颌窦,利用锥形束投照计算机重组断层影像(CBCT)扫描,并完成局部解剖,详细观察上颌窦形态、位置、容积、自然窦口位置及与周围组织的毗邻关系。另购买2只健康成年比格犬,利用CBCT确定上颌窦窦底,经腭侧开窗,显露软组织,夹取该位点黏膜行组织学检查,光学显微镜下验证所夹取黏膜是否为上颌窦黏膜。结果比格犬上颌窦形状略似锥形,前部较窄,后部宽大,位于上颌第3前磨牙与第1磨牙之间的腭侧,四周均有骨壁包绕。于第4前磨牙远中牙尖腭侧,距腭中缝约17~18mm处可见上颌窦最低点。同一个体双侧对比,差异无统计学意义。结论比格犬双侧上颌窦无明显差异,有利于上颌窦相关研究进行随机分组;窦腔内无明显骨嵴或分隔,降低窦黏膜穿孔的危险;行上颌窦外提升时,结合CBCT于上颌窦最低点经腭侧骨板开窗是最佳的术式。     

Craniofacial structure in Marfan syndrome: a cephalometric study

Marfan syndrome (MFS) is a connective tissue disorder with autosomal dominant inheritance. Mutations in the FBN1 gene cause deficient processing of fibrillin-1, the main constituent of extracellular microfibrils, affecting tissues displaying elastic properties. Clinical manifestations are widespread and involve the skeletal, ocular, cardiovascular and pulmonary systems, skin and integumentum, and dura. A highly arched palate and retrognathia have been assigned to the symptoms with minor diagnostic specificity, although epidemiological data on prevalence are lacking yet. Twenty-six patients with MFS (n = 26) were studied for craniofacial characteristics using cephalometric measurements on lateral cranial radiographs. The purposes of this study were (1) to compare cephalometric variables of MFS group with age- and sex-matched population norms, and (2) to assess differences in palatal vault dimensions among adult MFS (n = 17) and matched controls (n = 32) by means of cephalometric measurements. Significant differences with population norms were found in the structures of the cranial base, the maxillary complex, the mandible body, and the relations of the jaws with respect to the cranial base and to each other. Palatal height and palatal length were significantly larger in MFS, and were significantly correlated to each other and to the height of the maxillo-alveolar processus. The present data disprove in part previously reported findings, possibly due to biased patient selection in these studies or demographic differences. However, a strong correlation was found between maxillary/mandibular retrognathia, long face, highly arched palate, and MFS. A combination of both intrinsic genetic factors and environmental factors is suggested as a possible explanation for specific morphogenetic aspects of the craniofacial complex in MFS.     

Chick frontonasal process excision significantly affects mid-facial development

Summary The midfacial region in vertebrates may be considered as developing from five separate processes, namely the central frontonasal process (FNP) and the paired maxillary and lateral nasal processes. Relatively little is known about the mechanisms whereby these processes interact to produce structures of the neonatal/adult face. This study was undertaken to gain some insights into the events involved in this process, and involved observing the effects on facial development in the chick of surgical excision of the FNP, prior to its fusion with the other facial processes. In the absence of the FNP, outgrowth of the upper beak was dramatically reduced, agenesis of the primary palate occurred, and development of the maxillary processes and palatal shelves was impaired. Thus, in the chick, the frontonasal process plays a major role in midfacial morphogenesis. Not only does the FNP provide the primary palate and a contribution to the development of the nasal septum, it is also important in the ordered development of the maxillary processes and of the definitive secondary palate contributions which have not emerged clearly from in vitro and teratogenic studies.     

Study of Metopic Suture in the Adult Human Skulls of North India

The Metopic or Frontal Suture is formed at the meeting of the two halves of Frontal bone, in the midline. Normally it starts to close in the second year of life and within a short duration, gets completely obliterated. At times there may be a partial or complete failure of this obliteration- so when a complete metopic suture is present from Nasion to Bregma, it is known as Metopism.The present study was undertaken to observe the incidence of Metopic suture and Metopism in the adult human skulls of North India. For this purpose, 1020 skulls were observed, belonging to the Anthropology Museum of Department of Anatomy, GSVM Medical College Kanpur. Metopic suture was found to be present in the midline, in altogether 184 skulls (18.04%); out of which complete persistent Metopic suture (or Metopism) was reported in 36 skulls (3.5%) and partially obliterated suture in 148 skulls (14.6%)- it was present in the lower part of Frontal bone in 142 skulls (14%), in the upper part in 4 skulls (0.38%) and in the middle part in 2 skulls (0.19%). The upper end of Metopic suture was observed to meet the median sagittal suture, end-to-end, at Bregma in 6 skulls (15%) while in the rest of 34 skulls (85%), the upper end of Metopic suture failed to meet the anterior end of median sagittal suture and the deflection ranged between 12 mm to 2 mm. Mean suture length was computed to be 128 mm.     

Multi-layered hypertrophied MEE formation by microtubule disruption via GEF-H1/RhoA/ROCK signaling pathway

Background: Formation of the secondary palate is complex and disturbance during palatal fusion may result in cleft palate. The processes of adhesion, intercalation, and disappearance of medial edge epithelia (MEE) are characterized by morphological changes requiring dynamic cytoskeletal rearrangement. Microtubules are one of the cytoskeletal elements involved in maintenance of cell morphology. Microtubule‐disrupting drugs have been reported to cause craniofacial malformations including cleft palate. The mechanisms underlying the failure of palatal fusion remain poorly understood. We evaluated the effect of nocodazole (NDZ), a drug that disrupts microtubules, on palatal fusion in organ culture. Results: NDZ caused failure of palatal fusion due to the induction of a multi‐layered hypertrophied MEE in the mid‐region of the secondary palatal shelves. Microtubule disruption increased RhoA activity and stress fiber formation. Pharmacological inhibition of the RhoA/ROCK pathway blocked multi‐layered MEE formation. Partial prevention of hypertrophied MEE was observed with Y27632 and cytochalasin, but not with blebbistatin. NDZ induced re‐localization of GEF‐H1 into cytoplasm from cell–cell junctions. Conclusions: The present study provided evidence that the GEF‐H1/RhoA/ROCK pathway plays a pivotal role in linking microtubule disassembly to the remodeling of the actin cytoskeleton, which resulted in a multi‐layered hypertrophied MEE and failure of palatal fusion. Developmental Dynamics 241:1169–1182, 2012. © 2012 Wiley Periodicals, Inc.     

Observation of maxillary sinus septa and bony bridges using dry skulls between Hellman's dental age of IA and IIIC

Maxillary sinus septa and bony bridges were observed using dry skulls in childhood, classified based on Hellman's dental age, to clarify maxillary sinus septum formation. Eighty-eight maxillary sinuses of 44 dry skulls and a cone-beam computed tomography (CBCT) unit were used. The locations of the septum, defined as a pointed bony structure originating from the inferior wall, and bony bridge, defined as a bony structure between the maxillary sinus wall and dental germ, were antero-posteriorly recorded, and the superoinferior distance, distance from the bony palate, and angle to the median palatine suture were measured. The rate of septum presence in the maxillary sinus was high (41.7%) in IIIC, and the septa were located in the deciduous molars, premolars, and molars. Also, all bony bridges were related to the median maxillary sinus wall, and the rate of the maxillary sinus showing a bony bridge was high in IIA and IIIA. Septum presence in the maxillary sinus was observed in IIA, IIC, IIIA, IIIB, and IIIC of Hellman's dental age. Also, bony bridges were observed in IC, IIA, IIC, IIIA, IIIB, and IIIC of Hellman's dental age.