Zygomatic Process Research Articles

Morphological description of the temporomandibular joint ligaments in domestic pigs.

The temporomandibular joint (TMJ) ligaments play crucial roles in its function or dysfunction. The objective of this study was to describe the macro and microscopic morphology of these ligaments in domestic pigs, aiming to: (1) expand knowledge about the species; (2) provide anatomical references for advancing veterinary therapy and utilizing pigs as animal models in craniofacial research. Heads of young Sus scrofa domesticus were dissected to identify TMJ ligaments. Fragments of these ligaments were collected and processed for subsequent histological analysis with Haematoxylin and eosin staining. The results were qualitatively described. Pigs exhibited a TMJ reinforced by three individualized capsular ligaments: a lateral ligament, attaching to the ventral margin of the zygomatic process of the temporal bone and the lateral margin of the mandibular neck; a caudomedial ligament, attaching to the retroarticular process of the squamous part of the temporal bone and the caudomedial margin of the mandibular neck and a caudolateral ligament, attaching to the ventral margin of the base of the zygomatic process of the temporal bone and the caudal margin of the mandibular neck. The lateral ligament exhibited a greater constitution of dense irregular connective tissue, while the caudomedial and caudolateral ligaments showed a greater constitution of dense regular connective tissue. It is concluded that the TMJ of pigs presents one more ligament than horses, cattle, dogs, cats and what has been described for pigs themselves. We believe these results may contribute to the improvement of veterinary clinical and surgical therapy overall, as well as provide essential morphological information for a better interpretation and application of interspecies results in craniofacial research using pigs as an experimental model, as in the case of humans.

Orthodontic maxillary molar movement-induced zygomatic pillar remodeling and its consequences on occlusal characteristics and stress distribution

ObjectiveWe aimed to evaluate changes in the zygomatic pillar during orthodontic treatment involving premolar extraction, analyze the effects of maxillary first molar movement on zygomatic pillar remodeling, and examine occlusal characteristics and stress distribution after remodeling.MethodsTwenty-five patients who underwent premolar extraction were included in the study. The zygomatic pillar measurement range was defined, and cross-sectional areas, surface landmark coordinates, alveolar and cortical bone thicknesses, and density changes were assessed using Mimics software based on the cone-beam computed tomography scans taken before (T0) and after the treatment (T1). Multiple linear regression analysis was performed to determine the correlation between changes in the zygomatic pillar and maxillary first molar three-dimensional (3D) movement and rotation. Additionally, the correlation between pillar remodeling and occlusal characteristics was analyzed by Teetester. Pre- and post-reconstruction 3D finite element models were constructed and loaded with an average occlusal force of two periods.ResultsThe morphological and structural remodeling of the zygomatic pillar after orthodontic treatment involving premolar extraction showed a decreased cross-sectional area of the lower segment of the zygomatic pillar. The zygomatic process point moved inward and backward, whereas the zygomatico-maxillary suture point moved backward. The thicknesses of the zygomatic pillar alveolar and cortical bones were thinner, and reduced alveolar bone density was observed. Simultaneously, the movement and angle change of the maxillary first molar could predict zygomatic pillar reconstruction to a certain extent. With decreasing the total occlusal force and the occlusal force of the first molar, occlusal force distribution was more uniform. With zygomatic pillar remodeling, occlusal stress distribution in the zygomatic alveolar ridge decreased, and occlusal stress was concentrated at the junction of the vertical and horizontal parts of the zygomatic bone and the posterior part of the zygomatic arch.ConclusionsOrthodontic treatment involving premolar extraction led to zygomatic pillar remodeling, making it more fragile than before and reducing the occlusal force of the maxillary first molar and the entire dentition with stress concentrated in weak areas.Clinical relevanceNo other study has focused on the effects of orthodontics on pillar structures. The present study indicates that the mesial movement of the maxillary first molar weakened the zygomatic pillar and reduced occlusal function, thereby providing insights for inserting anchorage screws and facial esthetics.

Anatomical study on the posterior alveolar canal in maxillary tuberosity region using computed tomography

ObjectiveThis study aimed to identify the anatomical characteristics of the posterior alveolar canal (PAC) and related maxillary bone using computed tomography (CT). MethodsThe study included 40 Japanese cadavers (70 hemi-heads), comprising 23 males (41 hemi-heads) and 17 females (29 hemi-heads). Simple CT data of the maxillary bone region of the specimens were obtained and analyzed using a measurement software with reference to the Frankfurt horizontal (FH) plane to identify the PAC in the maxillary tuberosity region, alveolar crest (AC), and corner of the inferior crest of the zygomatic process (CICZP). The shortest distances between the PAC and the respective landmarks and the smallest width of the posterior wall of the maxillary sinus (WPWMS) at the PAC level were calculated and analyzed statistically. ResultsOf all specimens, the mean and SD of AC-PAC: 21.4 ± 3.32 mm, horizontal PAC-CICZP: 15.1 ± 2.89 mm, vertical PAC-CICZP: 5.70 ± 3.15 mm, WPWMS: 0.81 ± 0.31 mm, and the coefficients of variation ranged 15.5–55.3%. In the WPWMS, the mean value was statistically smaller in the female group (0.59 mm) than in the male group (0.96 mm) (p < 0.001). ConclusionsThe results showed certain tendencies in the distances between the PAC and the respective anatomical landmarks with large variations. The thickness of the posterior wall of the maxillary sinus was thinner in females than in males. However, it is < 1 mm in both sexes, and external forces caused by trauma or surgery may fracture the posterior wall of the maxillary sinus and damage the posterior superior alveolar artery regardless of sex.

Breed-Specific Skull Morphology Reveals Insights into Canine Optic Chiasm Positioning and Orbital Structure through 3D CT Scan Analysis.

This study's CT scan-based morphometric analysis of 50 adult dogs explored the relationship between skull shape variations (determined by the skull index, SI), optic chiasm, optic canals, and orbital shape. Dogs were classified as brachycephalic (SI ≥ 59), mesocephalic (SI ≥ 51 but <59), and dolichocephalic (SI < 51). No significant age or weight differences were observed. Skull lengths (brachycephalic: 11.39 ± 1.76 cm, mesocephalic: 15.00 ± 2.96 cm, dolichocephalic: 17.96 ± 3.44 cm) and facial lengths (brachycephalic: 3.63 ± 1.00 cm, mesocephalic: 6.46 ± 1.55 cm, dolichocephalic: 8.23 ± 1.03 cm) varied significantly, with shorter orbital depths (brachycephalic: 2.58 ± 0.42 cm, mesocephalic: 3.19 ± 0.65 cm, dolichocephalic: 3.61 ± 0.77 cm) in brachycephalic dogs. The optic chiasm-to-inion horizontal length ratio to cranial horizontal length positively correlated with the SI (r = 0.883, p < 0.001), while the ratio to neurocranial length showed no SI correlation (range: 55.5-75.0). Brachycephalic breeds had a significantly wider optic canal angle (93.74 ± 16.00°), along with broader lacrimal-zygomatic and zygomatic frontal process angles. These findings highlight the zygomatic bone's role in influencing breed-specific orbital variations by connecting the face to the neurocranium, projecting the orbital rim outward and forward with facial shortening.

Template-based target point localization for occlusion of the middle meningeal artery during evacuation of space-occupying chronic subdural hematoma.

Endovascular middle meningeal artery (MMA) occlusion may help reduce the risk of recurrence after burr hole evacuation of chronic subdural hematoma (cSDH) but carries an additional periprocedural risk and remains hampered by logistical and financial requirements. In this study, the authors aimed to describe a simple and fast technique for preoperative MMA localization to permit burr hole cSDH evacuation and MMA occlusion through the same burr hole. The authors performed a preclinical anatomical and prospective clinical study, followed by a retrospective feasibility analysis. An anatomical cadaver study with 33 adult human skulls (66 hemispheres) was used to localize a suitable frontal target point above the pterion, where the MMA can be accessed via burr hole trephination. Based on anatomical landmark measurements, the authors designed a template for projected localization of this target point onto the skin. Next, the validity of the template was tested using image guidance in 10 consecutive patients undergoing elective pterional craniotomy, and the feasibility of the target point localization for cSDH accessibility was determined based on hematoma localization in 237 patients who were treated for a space-occupying cSDH in the authors' department between 2014 and 2018. In the anatomical study, the mean perpendicular distance from the zygomatic process to the target point in the frontoparietal bone was 4.1 cm (95% CI 4-4.2 cm). The mean length along the upper margin of the zygomatic process from the middle of the external auditory canal to the point of the perpendicular distance was 2.3 cm (95% CI 2.2-2.4 cm). The template designed according to these measurements yielded high agreement between the template-based target point and the proximal MMA groove inside the frontoparietal bone (right 90.9%; left 93.6%). In the clinical validation, we noted a mean distance of 4 mm (95% CI 2.1-5.9 mm) from the template-based target point to the actual MMA localization. The feasibility analysis yielded that 95% of all cSDHs in this cohort would have been accessible by the new frontal burr hole localization. A template-based target point approach for MMA localization may serve as a simple, fast, reliable, and cost-effective technique for surgical evacuation of space-occupying cSDHs with MMA obliteration through the same burr hole in a single setting.

Bilateral maxillary odontogenic fibroma: a case of rare occurrence

Aim: To report the case of a patient diagnosed with bilateral odontogenic fibroma in the maxilla that was surgically removed. Clinical conduct: A 32-year-old female patient was referred to the Santa Casa de Montes Claros Hospital for the removal of a lesion in the maxilla. Intraoral examination revealed a mixed lesion in the maxilla, bilaterally, with a suspected odontogenic tumor. Cone beam computed tomography showed an expansive lesion in the posterior region of the right and left maxilla, extending to the palatine and zygomatic processes. An incisional biopsy was performed and revealed the proliferation of spindle cells amid collagenized stroma, with the presence of mitoses and foci of concentric calcification, accompanied by lacerated bone trabeculae and fibroconnective tissue with edema, which were compatible with the diagnosis of odontogenic fibroma. During removal, the lesion detached easily and it was necessary to remove a premolar corresponding to the area involved, which presented advanced mobility due to loss of support, followed by adequate cleaning of the surgical site. Results: After the surgery to remove the lesion, the patient remained under clinical follow-up to evaluate the evolution of the case as well as its possible complications. Conclusion: This case highlights the importance of a careful clinical, imaging, and histopathological approach to lesions in the maxilla, for correct diagnosis and referral of the patient for appropriate treatment.

The Lateral Supraorbital Approach: 2-Dimensional Operative Video.

The lateral supraorbital approach (LSO), a minimally invasive alternative to the pterional approach, can be used for anterior circulation aneurysms (except distal anterior cerebral artery), some posterior circulation aneurysms, and tumors located around the sellar and suprasellar regions. Performing one-layer myocutaneous flap that is retracted anteriorly, exposure of the superior temporal line, and zygomatic process of the frontal bone and the inferior limit of the craniotomy represent the upper edge of the Sylvian fissure, exposing the anterolateral skull base. Skin incision behind the hairline, one-layer myocutaneous flap retracted anteriorly, minimal detachment of the temporalis muscle, burr hole over the superior temporal line, and craniotomy of 4 cm in diameter (inferior limit of the craniotomy represents the Sylvian fissure). Potential risks include opening of the frontal sinus, entering the orbit and exposure of the orbital fat, wrong craniotomy location, and limited exposure. Inadequate craniotomy size limits instruments maneuverability. To avoid complication, identification of anatomic landmarks, sinus closure, preoperative evaluation of computed tomography scans, and use of neuronavigation are necessary. This requires surgical expertise and familiarity of minimal invasive craniotomies. Anatomic limitations of the LSO include temporomesial region, distal Sylvian +/-, posterior communicating artery aneurysms medial projection, retro carotid space, and carotid cave. For pathologies requiring an additional lateral trajectory, we use an extended LSO, drilling the sphenoid wing through the fronto-pterio-orbital window without drilling of the temporal bone. Additional variations include performing an intradural or extradural clinoidectomy. The patient consented to the procedure and to the publication of their image.

Topographical anatomy of the mandibular foramen in the dromedary camels (Camelus dromedarius): an extraoral approach for the inferior alveolar nerve blocks.

Understanding the clinical anatomy of the head is essential for performing proper inferior alveolar nerve (IAN) block anesthesia to facilitate invasive dental procedures in camels. However, osteometric data related to the IAN in camels are lacking. This study was carried out to accurately locate the mandibular foramen (MF) and the course of the IAN in the camel head and to establish an approach for its localization in clinical practice. To achieve these aims, eight osteometric measurements were used to determine the location of the MF in relation to its surrounding structures in six cadaveric skulls of adult camels. Four camel heads were dissected, and the course of the IAN inside the mandibular canal was studied. In addition, four heads were used as a trial for the extraoral approach to the IAN block using contrast radiographs based on established metric indices. Dissection of the four camel heads revealed that the MF was located near the intersection of two lines passing through the occlusal surface of the mandibular cheek teeth and at the midpoint of the zygomatic process of the temporal bone. Significant differences were not observed between the right and left mandibles. Successful deposition of the contrast medium near the MF was observed in all examined specimens. This study reports a new, simple approach to reaching the IAN at the MF. However, further clinical validation of the proposed technique is required.

Digitalized diagnosis and treatment of pigmented villonodular synovitis of temporomandibular joint: a case report.

Pigmented villonodular synovitis (PVNS) is a rare locally aggressive benign tumor in the temporomandibular joint (TMJ). This paper presents a patient with TMJ-PVNS involving masseteric space, temporal bone, zygomatic process, and mandibular ramus. Digital technique was used to determine the boundary of the lesion and reconstruct the normal glenoid fossa. The temporalis myofascial flap was transplanted between titanium mesh and condyle to reconstruct the disk after the complete resection of the tumor. The patient's facial profile is symmetrical, with a mouth ope-ning of 43 mm. No local recurrence and complications, such as cerebrospinal fluid fistula and encephaloceles, were detected during 30-month follow-up period.

The Value of Intraoperative Computed Tomography in the Treatment of Zygomatic Complex Fractures

Due to the complex anatomical morphology and lack of anatomic markers on the surface of zygomatic complex (ZMC), the treatment results of ZMC fractures are often suboptimal. The study aimed to evaluate the effectiveness of intraoperative computed tomography (ICT) in the treatment of unilateral ZMC fractures, and further study the feasibility of ICT to replace early postoperative Computed Tomography (CT). The investigators designed a retrospective cohort study. Adult patients who underwent surgery with unilateral ZMC fractures were enrolled. According to whether intraoperative CT was used, the subjects were divided into the ICT group and the control group (without ICT). Five distances and 3 angles representing bilateral ZMC symmetry were main outcome variables. The differences of outcome variables were compared between the 2 groups and the indices of ICT group were further compared with their postoperative indices. Demographics (eg age), etiology (eg traffic injury), dysfunction (eg diplopia), and surgical approach (eg vestibular incision) were collected as covariates while we conducted clinical investigation, examination, and implementation. The data were analyzed using independent-samples t test, paired-samples t test, Mann-Whitney U test, and χ2 test. P value < .05 was considered statistically significant. A total of 60 patients (18 to 59years) were enrolled in this study. All median values of the measurements in the ICT group were smaller than those in the control group, and the differences of horizontal displacement distance (0.56 vs 1.02mm), anteroposterior displacement distance (1.69 vs 2.34mm, 0.90 vs 2.35mm), horizontal angle of bilateral zygomatic arch (2.31 vs 4.19°), and horizontal angle of bilateral zygomatic process (1.77 vs 2.94°) were significantly different between the 2 groups with P value < .05. Moreover, there was no statistically significant difference in all indices between the intraoperatively and postoperatively injured sides in the ICT group. ICT can improve the treatment outcomes of ZMC fractures by evaluating the fracture reduction adequacy during surgery. Moreover, ICT can replace early postoperative CT.

Cranial and endocranial comparative anatomy of the Pleistocene glyptodonts from the Santiago Roth Collection

With their odd cranial features, glyptodonts, closely related to extant armadillos, are a highly diverse group of the South American megafauna. Doedicurus, Glyptodon, Panochthus, and Neosclerocalyptus were present in the “Pampean Formation” during the Pleistocene, and they are all exceptionally preserved in the Santiago Roth Collection, thus offering the possibility of investigating these four well-diversified genera. A total of 13 specimens (seven species) were analysed and compared in a qualitative/quantitative study of external cranial remains and endocranial reconstructions (i.e., braincase and associated cranial canals, and inner ears). We report on anatomical features that contribute to existing phylogenetic matrices; many of them are new potential synapomorphies supporting the current hypotheses regarding the evolutionary history of the Pleistocene glyptodonts. These include the anterior cranial shape, the position of the basicranium in respect to the whole cranium, the shape of the cranial roof, the position of the largest semicircular canal, and the inclination of the cerebrum. They may represent new shared-derived features among Glyptodon, Doedicurus, Neosclerocalyptus, and Panochthus. We also provide detailed comparative descriptions highlighting new potential convergences in respect to current phylogenies, concerning, for instance, the shape of the foramen magnum, the global shape of the cranium, orbital shape, cochlear position, and a strong protrusion of the zygomatic process of the squamosal. In light of these results, we discuss morphological transformations across phylogeny. The endocranial comparison brought insights on the phylogenetic patterns of cranial canal evolution.

Изменчивость лицевого скелета у носителей джетыасарской археологической культуры Восточного Приаралья по данным 3D геометрической морфометрии

Introduction. The origin of the Jetyasar culture’s population remains a subject of debate. It was generally accepted that the Xiongnu penetrated into the Aral Sea region and participated in the formation of the local population. Previous studies have shown a complex and admixed origin of the Jetyasar people. But the spread of the head deformation tradition in this population imposes serious limitations on the application of craniometric methods for studying Jetyasar samples. Those limitations can be potentially mitigated with the use of geometric morphometrics (GM). The purpose of this work was to assess the degree of variation in the facial skeleton of the Jetyasar people in comparison with populations of the Early Iron Age and the Hunno-Sarmatian period. Material and methods. Digital, three-dimensional models of the skulls were created. Ten landmarks were placed on each of the models and subjected to general Procrustes analysis (GPA) and principal component analysis (PCA). Results. The first PC of the analysis of the total male sample reflects variation in the height of the face, nasal bridge protrusion, and the relative width of the infraorbital region. The second component describes the height of the lateral part of the zygomatic process of the maxilla and the adjacent part of the zygomatic bone. The Kosasar 2 male sample is the most diverse morphologically. This burial ground, according to archeological data, belonged to a migrant population related to the Xiongnu. In the female total sample, high values of the first PC are associated with a tall face, a weak nasal bridge protrusion, and a long zygomatic-maxillary suture. The second PC describes the morphology of the zygomatic process of the upper jaw. The Jetyasar samples are morphologically distinct from the skulls from China, Mongolia, Western Siberia, and Southern Siberia. An exception are the crania from the burial grounds of Kosasar 2, 3, and Altyn-Asar 4t which are similar to the early Iron Age samples from China (inner Mongolia, Warring States period, 5 th – 3rd centuries BC), Mongolia (Xiongnu period), and Tuva (Arzhan-2). Discussion. The Xiongnu migration could become a catalyst for the admixture and ethnogenetic processes in the region. Conclusion. Our study shows that the population of the Jetyasar culture was morphologically heterogeneous at all stages of the culture’s development. The hypothesis about the migrant roots of a part of the population is confirmed by our data.

Geometric and Inertial Properties of the Pig Head and Brain in an Anatomical Coordinate System.

Porcine models in injury biomechanics research often involve measuring head or brain kinematics. Translation of data from porcine models to other biomechanical models requires geometric and inertial properties of the pig head and brain, and a translationally relevant anatomical coordinate system (ACS). In this study, the head and brain mass, center of mass (CoM), and mass moments of inertia (MoI) were characterized, and an ACS was proposed for the pre-adolescent domestic pig. Density-calibrated computed tomography scans were obtained for the heads of eleven Large White × Landrace pigs (18-48kg) and were segmented. An ACS with a porcine-equivalent Frankfort plane was defined using externally palpable landmarks (right/left frontal process of the zygomatic bone and zygomatic process of the frontal bone). The head and brain constituted 7.80 ± 0.79% and 0.33 ± 0.08% of the body mass, respectively. The head and brain CoMs were primarily ventral and caudal to the ACS origin, respectively. The mean head and brain principal MoI (in the ACS with origin at respective CoM) ranged from 61.7 to 109.7kgcm2, and 0.2 to 0.6kgcm2, respectively. These data may aid the comparison of head and brain kinematics/kinetics data and the translation between porcine and human injury models.

An irrefutable unambiguous insight into zygomatic air cell defect (ZACD)

Zygomatic air cell defect (ZACD) of the temporal bone, has been characterized as the auxiliary air cells in the zygomatic process and articular eminence of the temporal bone. They present as unresectable findings in the zygomatic process of the temporal bone and articular tubercle. They are crucial, as they signify regions of weak resistance and the spread of disease. Comprehension of the decrepit regions in the zygomatic bones with Cone Beam Computed Tomography (CBCT), and the imaging of choice in maxillofacial disorders for its superior 3D anatomical reconstruction and minimal distortion, are indispensable in the diagnosis, treatment planning and placement of endosseous or basal dental implants to elude complications. 154 CBCT images of subjects aged between18 and 70 years with optimal diagnostic quality and area coverage satisfying the selection criteria without the history of maxillofacial fractures, pathologies, anomalies involving the middle one third of the face were analysed. The overall prevalence of ZACD was in 16 (10.4%) subjects, with 9 in females (56.25%) and in 7 males (43.75%). The men-to-women ratio was 1:1.28. It was also revealed that bilateral incidence of ZACD was more common and the prevalence of ZACD the highest 8 (50%) in the age group of 21- 30 years. This study highlights the importance of research on the prevalence of the ZACD on CBCT, which was exiguous in the past, and compares with similar studies done using panoramic radiographs. This study paves the way for more studies employing CBCT to justify the findings we have expressed.

Neanderthal child's maxilla from Baume Moula-Guercy (Soyons, Ardèche, France).

This article provides an ontogenetically-based comparative description of the Guercy 3 partial child's maxilla with Rdm2 -RM1 and unerupted RI2 -RP4 from Baume Moula-Guercy (MIS 5e) and examines its affinities to European and Middle Eastern Middle-to-Late Pleistocene (≈MIS 14-MIS 1) Homo. Description of the Guercy 3 maxilla and dentition (7.0 year ± 0.9 month) is based on observations of original fossils, casts, CT scans, literature descriptions, and virtual reconstructions. Our ontogenetic sample comprises a Preneanderthal-Neanderthal group and a Homo sapiens group. These groups are subdivided into (1) Preneanderthals (≈MIS 14-9), Early Neanderthals (MIS 7-5e), and Late Neanderthals (MIS 5d-3), and (2) Middle (MIS 5), Upper (MIS 3-2), and Late Upper Paleolithic (≈MIS 1), and recent H. sapiens. Standard techniques were employed for measurements and developmental age determinations.The Guercy 3 maxilla lacks changes found in Late Neanderthals, including the positioning of the root of the zygomatic process, infraorbital and nasal plates, premaxilla, buccal and labial alveolus, maxillary sinus, nasal cavity, and verticality of anterior tooth implantation. The morphology of the Guercy 3 maxilla more closely approximates that of Sima de los Huesos Preneanderthals, while the dentition more closely approximates the Early-Late Neanderthal condition. Maxillary remains of children and juveniles between MIS 14-MIS 5e are rare, and the available sample is fragmentary and distorted. Although fragmentary, the Guercy 3 maxilla is undistorted and provides new insights into the evolution of the midface in Neanderthals.

Cranial adaptations of the Night Parrot (Psittaculidae: Pezoporus occidentalis), a cryptic nocturnal bird

ABSTRACT The Night Parrot Pezoporus occidentalis is a critically endangered, elusive, nocturnal bird that is difficult to study in the field. Much is unknown about its biology, including how it navigates at night. A previous investigation of the eye and brain revealed that it likely has poor nocturnal vision, but its other sensory abilities, and overall skull anatomy, have not yet been investigated. This osteological study, based on micro-CT-scans of the holotype, describes and compares the anatomy of the Night Parrot skull, and identifies its possible ecological adaptations. Specialised ear anatomy suggests that the Night Parrot has enhanced acoustic abilities, in contrast with its diurnal congener P. wallicus and the only other nocturnal parrot, the Kakapo Strigops habroptila. The Night Parrot’s uniquely enlarged exoccipital bones may amplify sound, and bilateral ear asymmetry, not identified in any other parrot species, likely enhances its directional hearing, as in many species of owl. Enlarged exoccipitals displace the zygomatic processes and constrain orbit size, suggesting an evolutionary trade-off between hearing and vision. The auditory abilities of the species require deeper investigation, but our anatomical observations indicate that the potential impacts of noise disturbance may warrant consideration in Night Parrot conservation strategies as a precaution.

Clinical evaluation of antral septal maxillary sinus floor elevation by the disk-up sinus reamer

Objective: To investigate the clinical effect of disk-up sinus reamer (DSR) in maxillary sinus floor elevation with maxillary sinus septum. Methods: Twenty-four patients were included between January 2019 to January 2020 in Department of Oral Implantology, The Affiliated Hospital of Qingdao University. There were 10 males and 14 females with the age of (39.3±11.7) years old (range 22-56 years). Pre-operative(T0) cone-beam CT (CBCT) was taken for measurement and analysis. All patients were divided into group E (easy situations, septum located anterior to the zygo-matic process), group M (moderate situations, septum located pos-terior to the zygo-matic process) and group D (difficult situations, sagittally oriented septum). The maxillary sinus floor was grafted through the crestal approach by DSR and implants were placed simultaneously. Permanent repair was performed 6-8 months after operation. All patients underwent CBCT before surgery, after surgery immediately (T1), 6 months after surgery(T2), 1 year after surgery(T3), 2 year after surgery(T4). The residual bone height (RBH) and the vertical bone height (VBH) were analyzed. The mucosal perforation rate, implant survival rate were counted. Results: All the 24 patients completed the Maxillary sinus lift surgery successfully and 24 implants were placed simultaneously. All patients had no headache, dizziness. The mucosal perforation rate was 0. The survival rate of implants during the healing period was 100%(24/24). The RBH was (5.81±2.56) mm pre-operation, the VBHT1, VBHT2, VBHT3 and VBHT4 were (11.82±1.09), (10.98±0.52), (10.66±0.44) and (10.40±0.33) mm, respectively. The differences between the groups by pairing test were statistically significant (F=187.70, P0.001), expect VBHT3 and VBHT4 (P=0.071). Bone resorption and remodeling mainly occurred 1 year after surgery. One patient developed peri-implantitis 18 months after surgery. Conclusions: With the RBH of implant site>2 mm and existence of maxillary sinus septum, using DSR for sinus floor elevation has a high success rate. It can obtain enough bone height and complete the simultaneous implantation to form a good osseointegration. The DSR is simple, safe and controllable, and can shorten the operation time.

Subfascial dissection and extended temporal muscle detachment for middle fossa approach.

The soft tissue dissection for the middle fossa approach requires adequate management of the neuro, vascular, and muscular structures in order to maximize exposure and diminish morbidities. An incision anterior to the tragus is performed, extending from the zygomatic process to the superior temporal line. The superior temporal artery is exposed, followed by a subfascial dissection of the frontalis nerve. The temporal muscle is dissected and released from the zygoma. All cranial landmarks are exposed for the 5 × 5cm temporal fossa craniotomy. This novel approach provides a safe and adequate access to perform an extended middle fossa craniotomy.

A new squaloziphiid-like odontocete from the Early Miocene of Patagonia expands the cetacean diversity in the southwestern Atlantic Ocean

ABSTRACT The Early Miocene Gaiman Formation, from Argentina, houses a taxonomic variety of odontocetes, mainly dominated by platanistoids and physeteroids. In this work, we describe a new medium-sized odontocete, Crisocetus lydekkeri gen. et sp. nov., based on a partial skull, which expands the diversity of odontocetes in the Early Miocene beds of Patagonia (Argentina). The phylogenetic analyses placed C. lydekkeri within the crown Odontoceti, stemward to delphinidans, ziphiids, and physeteroids. Crisocetus lydekkeri displays a set of characters that are shared with the members of the Squaloziphiidae family (i.e., Squaloziphius emlongi and Yaquinacetus meadi), such as a massive postglenoid process of the squamosal, ventrally longer than the posttympanic process and the exoccipital; apex of postglenoid process anteroposteriorly longer than transversely thick; presence of a deep emargination by a neck muscle fossa on the posterior end of the zygomatic process; basioccipital crests forming an angle of circa 70–90°; and a basioccipital width wider than 51% of the skull width in ventral view. Thus, we recognize a squaloziphiid-like morphology shared by C. lydekkeri, S. emlongi, Y. meadi, and even Dolgopolis kinchikafiforo. Our phylogenetic analyses partially support the inclusion of C. lydekkeri within Squaloziphiidae, however this family is recovered with low support. Finally, the presence of C. lydekkeri and even D. kinchikafiforo in the Early Miocene of Patagonia expands the paleogeographic distribution of squaloziphiid-like forms to the southwest coast of the Atlantic Ocean, suggesting that these taxa had an almost antitropical distribution.

Computer‐assisted removal of an ectopic tooth from the mandibular fossa through a mandibular condylectomy approach in a Comptois gelding

SummaryA 3‐year‐old Comptois gelding with a history of chronic fistulation at the base of the right ear was referred for the treatment of a unilateral ectopic tooth in the right temporal region. Cone‐beam computed tomography (CBCT) confirmed the presence of an ectopic tooth in the right mandibular fossa. The ectopic tooth was associated with a draining tract running through the zygomatic process of the right temporal bone. A total mandibular condylectomy provided a direct approach to the ectopic tooth, which was subsequently successfully removed. Long‐term follow‐up confirmed a satisfactory outcome despite the need for repeated debridement and persistence of a small draining tract 15 months postoperatively. Computer‐assisted surgery (CAS) provided precise anatomical intraoperative orientation for the condylectomy and subsequent removal of the ectopic tooth close to the calvarium. The use of CAS greatly facilitated surgery and minimised the risks of important collateral damage.