Osseointegration of Zirconia Implants after UV-Light or Cold Atmospheric Plasma Surface Treatment In Vivo

The influence of UV light and non-thermal plasma on the osseointegration of yttria-stabilized zirconia implants (Y-TZP) comparing the two methods is unclear. The aim of this study was to show the influence of these methods on the osseointegration of dental zirconia implants in an animal model. A total of 54 implants were either untreated, treated with UV light (UV), or non-thermal oxygen plasma for 12 min and inserted into the parietal bones of six domestic pigs. The animals were sacrificed after a healing interval of two, four, and nine weeks. The degree of osseointegration was determined using histomorphometric determination of bone-to-implant contact values (BIC) and the bone-to-implant contact values within the retentive parts of the implants (BAFO). BIC values decreased in all groups after four weeks of healing and re-increased after nine weeks in all groups. BAFO increased significantly over time in all groups. However, there were no statistically significant differences in BIC and BAFO values between the control group and the test groups and over time. Clinical studies may follow to confirm the influence of cold plasma and UV light on the healing and survival of zirconia implants.

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.

Study on Morphometric Features of Coronal Suture Along with it Absence and Craniosynostosis

Background: Cranial sutures are syndesmosis between the cranial bones. The coronal suture is oblique in direction and extends between the frontal and the parietal bones. Craniosynostosis is a rare birth defect that occurs when the coronal suture in the skull fuses prematurely, but the brain continues to grow and develop. This leads to a misshapen head. There are a number of forms of this defect, such as coronal, sagittal, lambdoid, and metopic. Materials and Methods: Total 500 skulls were used for study, coronal suture length measured by thread method, distance between Nasion to bregma and midsupraorbital rim to coronal suture were measured. For finding skull with absence of coronal, sagittal, lambdoid, and metopic suture, we examined many skulls during routine osteology classes of Medical, Dental and other medical sciences students. Around 500 skull observed and we find only one skull with absence of left coronal suture completely. Results: The length of coronal suture was 24.8+1.4cm length, the distance between nasion to bregma was 126.7 +10.25 mm and Midsupraorbital rim to cranial suture was 102.76+8.64mm We have found only one skull with absence of coronal suture. Some of the skulls shows partly fusion of sagittal, coronal sutures. The skull with complete absence of coronal suture showing the features of other sutures clearly and right side of coronal suture is showing the complete suture. The skull was not damaged and it is in perfect condition which was using by students for their osteology study. Conclusion: We found the skull with absence of left coronal suture, which may resulted due to craniosynostosis. It may be due to hot climate in India also might be resulted for absence of suture. KEY WORDS: Birth defect, Skull, Coronal suture, Craniosynostosis.

The application of augmented reality–based navigation for accurate target acquisition of deep brain sites: advances in neurosurgical guidance

OBJECTIVE The objective of this study is to quantify the navigational accuracy of an advanced augmented reality (AR)–based guidance system for neurological surgery, biopsy, and/or other minimally invasive neurological surgical procedures. METHODS Five burr holes were drilled through a plastic cranium, and 5 optical fiducials (AprilTags) printed with CT-visible ink were placed on the frontal, temporal, and parietal bones of a human skull model. Three 0.5-mm-diameter targets were mounted in the interior of the skull on nylon posts near the level of the tentorium cerebelli and the pituitary fossa. The skull was filled with ballistic gelatin to simulate brain tissue. A CT scan was taken and virtual needle tracts were annotated on the preoperative 3D workstation for the combination of 3 targets and 5 access holes (15 target tracts). The resulting annotated study was uploaded to and launched by VisAR software operating on the HoloLens 2 holographic visor by viewing an encrypted, printed QR code assigned to the study by the preoperative workstation. The DICOM images were converted to 3D holograms and registered to the skull by alignment of the holographic fiducials with the AprilTags attached to the skull. Five volunteers, familiar with the VisAR, used the software/visor combination to navigate an 18-gauge needle/trocar through the series of burr holes to the target, resulting in 70 data points (15 for 4 users and 10 for 1 user). After each attempt the needle was left in the skull, supported by the ballistic gelatin, and a high-resolution CT was taken. Radial error and angle of error were determined using vector coordinates. Summary statistics were calculated individually and collectively. RESULTS The combined angle of error of was 2.30° ± 1.28°. The mean radial error for users was 3.62 ± 1.71 mm. The mean target depth was 85.41 mm. CONCLUSIONS The mean radial error and angle of error with the associated variance measures demonstrates that VisAR navigation may have utility for guiding a small needle to neural lesions, or targets within an accuracy of 3.62 mm. These values are sufficiently accurate for the navigation of many neurological procedures such as ventriculostomy.

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.

iant extradural dermoid cyst in the right parietal-occipital region with obliteration of the transverse sinus

The study objective – to report a case of giant extradural dermoid cyst in a 48‑year-old woman; the cyst caused extensive erosion of the occipital bone and lower portions of the right parietal bone, which is quite rare.Case report. A 48‑year-old female patient was admitted to the Department of Neurosurgery, A. Ya. Kozhevnikov Clinic of Nervous System Diseases, University Clinical Hospital No. 3, I. M . Sechenov First Moscow State Medical University on 28.07.2020. In 2002, the patient noted the emergence of a 1‑cm subcutaneous formation in the right occipital region. The formation was slowly growing. On 17.12.2015, she underwent magnetic resonance imaging of the brain. It revealed a 2,5 × 4,4 × 4,0 cm extradural formation with clear contours and erosion of the occipital and right parietal bones. On 12.03.2020, she had contrast-enhanced magnetic resonance imaging, which demonstrated that the tumor was growing (its size was 3,0 × 6,4 × 5,5 cm). Magnetic resonance imaging scans also showed extensive erosion (6,4 × 5,4 cm) of the occipital and right parietal bones and obliteration of the right transverse sinus. On 28.07.2020, the patient underwent elective surgery, namely excision of the extradural dermoid cyst in the right parietooccipital region with simultaneous reconstruction of the calvarial bones using a titanium plate. The cyst capsule and its contents were completely removed. The capsule was tightly attached to the dura mater, but did not invade it. To remove small fragments of the capsule that could potentially invade the bone, we performed small marginal resection of the calvarial bones at the depth of 2–3 mm from the defect margin. After the removal of cyst capsule, well-defined furrow could be visualized on the dura mater in the projection of the obliterated transverse sinus. Five days postoperatively, the patient was discharged from hospital in satisfactory condition.Conclusion. Surgical treatment of extradural dermoid cysts implies radical removal of the tumor. Since the cyst capsule gets tightly attached to the edges of the bone defect along with bone erosion, the removal of such cysts as a single block is almost impossible. The risk of severe erosion of the skull bones caused by a dermoid cyst with extradural (and sometimes intradural) growth increases with age. Therefore, it is recommended to remove such tumors as early as possible. Patients with skull bone defects also require cranioplasty.

Anatomical description of the skulls of peccaries (Tayassu tajacu, Linnaeus 1758) by computed tomography

ABSTRACT The aim of this study was to evaluate the anatomical structures of the skulls of peccaries to establish the basis for their clinical study and future preclinical research. Ten skulls of adult peccaries were subjected to tomographic examination. The data obtained were processed via three-dimensional image reconstruction software (3D images). The reconstructions obtained from the neurocranium of the studied specimens allowed the identification and description of the following structures: nasal bone, frontal bone, parietal bones, incisor bone, maxillary bone, zygomatic bone, temporal bone, palatal bone, occipital bone, vomer bone, pterygoid bone, sphenoid bone, paranasal sinuses and orbit. Computed tomography proved to be an important diagnostic tool in the investigation of the skull of this species, allowing the acquisition of anatomical values not yet documented for the species in the literature.

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.

A Middle Pleistocene Homo from Nesher Ramla, Israel

It has long been believed that Neanderthals originated and flourished on the European continent. However, recent morphological and genetic studies have suggested that they may have received a genetic contribution from a yet unknown non-European group. Here we report on the recent discovery of archaic Homo fossils from the site of Nesher Ramla, Israel, which we dated to 140,000 to 120,000 years ago. Comprehensive qualitative and quantitative analyses of the parietal bones, mandible, and lower second molar revealed that this Homo group presents a distinctive combination of Neanderthal and archaic features. We suggest that these specimens represent the late survivors of a Levantine Middle Pleistocene paleodeme that was most likely involved in the evolution of the Middle Pleistocene Homo in Europe and East Asia.