Chemical Properties of Human Dentin Blocks and Vertical Augmentation by Ultrasonically Demineralized Dentin Matrix Blocks on Scratched Skull without Periosteum of Adult-Aged Rats

Vertical augmentation is one of the most challenging techniques in bone engineering. Several parameters, such mechano-chemical characteristics, are important to optimize vertical bone regeneration using biomaterials. The aims of this study were to chemically characterize human dentin blocks (calcified demineralized dentin matrix: CDM, partially demineralized dentin matrix: PDDM and completely demineralized dentin matrix: CDDM) (2 × 2 × 1 mm3) chemically and evaluate the behavior of PDDM blocks on non-scratched or scratched skulls without periosteum of adult rats (10–12 months old, female) as a vertical augmentation model. The dissolved efficiency of CDM showed 32.3% after ultrasonic demineralization in 1.0 L of 2% HNO3 for 30 min. The 30 min-demineralized dentin was named PDDM. The SEM images of PDDM showed the opening of dentinal tubes, nano-microcracks and the smooth surface. In the collagenase digestion test, the weight-decreasing rates of CDM, PDDM and CDDM were 9.2%, 25.5% and 78.3% at 12 weeks, respectively. CDM inhibited the collagenase digestion, compared with PDDM and CDDM. In the PDDM onlay graft on an ultrasonically scratched skull, the bone marrow-space opening from original bone was found in the bony bridge formation between the human PDDM block and dense skull of adult senior rats at 4 and 8 weeks. On the other hand, in the cases of the marrow-space closing in both non-scratched skulls and scratched skulls, the bony bridge was not formed. The results indicated that the ultrasonic scratching into the compact parietal bone might contribute greatly to the marrow-space opening from skull and the supply of marrow cells, and then bony bridge formation could occur in the vertical augmentation model without a periosteum.

Embryonic requirements for Tcf12 in the development of the mouse coronal suture

A major feature of Saethre-Chotzen syndrome is coronal craniosynostosis, the fusion of the frontal and parietal bones at the coronal suture. It is caused by heterozygous loss-of-function mutations in either of the basic HLH transcription factors TWIST1 and TCF12. While compound heterozygous Tcf12; Twist1 mice display severe coronal synostosis, the individual role of Tcf12 had remained unexplored. Here we show that Tcf12 controls several key processes in calvarial development, including the rate of frontal and parietal bone growth, and the boundary between sutural and osteogenic cells. Genetic analysis supports an embryonic requirement for Tcf12 in suture formation, as combined deletion of Tcf12 in embryonic neural crest and mesoderm, but not in postnatal suture mesenchyme, disrupts the coronal suture. We also detect asymmetric distribution of mesenchymal cells on opposing sides of the wild-type frontal and parietal bones, which prefigures later bone overlap at the sutures. In Tcf12 mutants, reduced asymmetry is associated with bones meeting end-on-end, possibly contributing to synostosis. Our results support embryonic requirements of Tcf12 in proper formation of the overlapping coronal suture.

Features of the formation of certain bones of the skull at the early stages of human ontogenesis

The study of morphogenesis and embryotopography of skull bones is important not only in understanding the normal development of the human embryo but also will improve existing methods of invasive treatment and visualization of various pathologies of the central nervous system in children.The aim was to investigate the peculiarities of morphogenesis and topography of some skull bones during the early stages of human ontogenesis.Material and methods. We have studied 14 series of consecutive histological sections of human embryos and pre-fetuses aged 6 to 11 weeks of intrauterine development by using a set of topical morphological methods (anthropometry, morphometry, histology, three-dimensional reconstruction).Results. The frontal and parietal bones appear at the end of the embryonic period as mesenchymal rudiments that gradually expand upwards from primary points of ossification (starting from the basolateral parts of the head). During 8th week of IUD, the germ of the ectomeningeal capsule is detected in the form of a thin plate, close to the brain. At the beginning of the pre-fetal period, histological signs of membranous ossification are revealed; frontal and parietal bones develop from paired rudiments, which gradually fuse, which was accompanied by active angiogenesis.Conclusions. The primary ossification centers in frontal and parietal bones of the human embryo appear at the beginning of embryological period and develop by membranous type. Two ossification centers appear in frontal and parietal bones and they gradually merge. At the beginning of the prenatal period, the rudiment of a small wing of the sphenoid, spheno-ethmoidal cartilage and signs of merging of both ossification centers in the parietal bone are detected.

The diagnostic dilemma of Masticator space tumor

The masticator space is an anatomical and functional entity centered on the mandibular ramus, which divides it into medial and lateral compartments. The masticator spaces considered paired supra-hyoid cervical spaces on each side of the face that extend from the angle of the mandible to the parietal bone. The masticator space contains the mastication muscles, posterior mandible, and mandibular nerve. They are separated from the nasopharynx by the parapharyngeal spaces bilaterally. Primary malignancy of the masticator space is very uncommon.Here we report a diagnostic dilemma of primary masticator space malignancy mistaken by nasopharyngeal carcinoma as the patient 40-year old gentleman presented with left lateral rectus palsy and left nasopharynx fullness.

Juvenile psammomatoid ossifying fibroma of the parietal bone and review of calvarial presentations: illustrative case

BACKGROUND Juvenile psammomatoid ossifying fibroma (JPOF) is an uncommon benign fibro-osseous lesion that only rarely presents in the calvaria. OBSERVATIONS The authors reported a case of JPOF in the left parietal bone of a 20-year-old patient and reviewed the 27 other cases of JPOF occurring in the calvaria as reported in the literature. LESSONS JPOF rarely presents in the calvaria, and because diagnosis is a histopathologic one, clinicians should consider this entity when presented with a lytic, expansile mass on imaging. Little is known about the molecular mechanisms driving development of JPOF. MDM2 amplification may play a role, although this was not seen in the case presented herein.

Anatomical Variation in South Indian Population in the Parietal Bones: Wormian Bone/Inca Bone

Background of the Study: Accessory bone found in the human skull bone between squamous part of parietal and in between lambda suture is called inca bone or wormian bone .A total of 100 dried skulls were examined to know the anatomical variations of the inter parietal bone. This variants of the bones are considered as normal. This knowledge of the study very useful for the neurosurgeon, orthopedic surgeons and forensic experts for their clinical intervention.

Isolated Progressive Enlargement of Head Mass as the First Symptom: A Rare Case Report of Cranial Metastasis of Hepatocellular Carcinoma and Literature Review

Background: This article presents a rare case of skull metastasis of primary hepatocellular carcinoma that manifests the isolated progressive enlargement of the head mass as the first symptom. Case presentation:A 65-year-old female patient presented an isolated painless mass in the head, which grew rapidly over the last month. Head CT revealed a 6.4 cm×5.6cm osteolytic destruction in the right parietal bone. MRI further revealed that the occupation was significantly enhanced in the T1 reinforced phase. The patient underwent total surgical resection. Postoperative pathology confirmed that the head mass was the skull metastasis from hepatocellular carcinoma (HCC). Conclusion: The case of skull metastasis from primary hepatocellular carcinoma is rare, and HCC patient with intracranial metastasis tends to have a rather poor prognosis. Surgical excision of the metastatic mass and radiotherapy can improve the life quality and prolong the survival time of the patient.