Search Results (189)

Background/Aim: Third molar impaction with the consequent root resorption of second molars often creates complexities in treatment planning and execution. In the past, the root canal treatment (RCT) of second molars was required in these cases to avoid pulp necrosis and infection. The aim of this paper is to report a surgical/retrograde approach for the maintenance of pulp vitality, proposed as retrograde vital pulp treatment (rVPT), in cases of asymptomatic or reversibly affected teeth with root resorptions caused by impacted adjacent teeth. Methods: A case report on the rVPT of two upper second molars with root resorption due to third molar impaction is presented. The chief complaint of the patient was a slight pain during bite involving the upper second molars. Heat and cold sensitivity tests were performed, suggesting a healthy pulp status. A cone beam computed tomography (CBCT) scan was performed to aid the diagnosis and treatment planning, showing bilateral upper third molar impaction and both distal roots of the upper second molars affected by external root resorption (ERR). In both cases, the third molar was surgically extracted, the surface of the root with ERR was smoothened and rVPT was carried out by performing a 3 mm retrograde preparation of the root canal and its retrograde sealing using a hydraulic calcium silicate-based cement (hCSCs). Results: Heat and cold sensitivity tests were performed 1 month, 3 months, 6 months and 1 year after the treatment. The patient reported no pain, and the pulp sensitivity was maintained in all follow-up periods. A CBCT scan was performed 24 months after the treatment, reporting a complete perirradicular endogenous bone apposition. Conclusions: Based on the successful clinical and radiographic outcomes observed in the present case after two years of follow-up, rVPT is proposed for the maintenance of pulp vitality in cases of asymptomatic or reversibly affected teeth with ERR caused by impacted adjacent teeth. Full article

Tomicus yunnanensis, a notorious forest pest in southwest China, primarily employs infochemicals to coordinate mass attacks that overcome host tree defenses. However, secondary visual cues, particularly detection of host color changes, also aid host location. This study characterized the compound eye structure and vision of T. yunnanensis using electron microscopy and phototaxis tests. The apposition eye contains 224–266 ommatidia, with asymmetry between left and right. Quadrilateral facets occupy the dorsal third, while hexagonal facets dominate elsewhere. Each ommatidium comprises a large corneal lens, an acone-type crystalline cone from four cone cells, and an open-type rhabdom formed by eight retinular cells (R7–R8 centrally, R1–R6 peripherally), surrounded by two primary and at least seventeen secondary pigment cells. Dark/light adaptation alters cone size/shape and rhabdom cross-sectional area/outline (without pigment granule movement) to regulate light reaching the photoreceptors. Behavioral observations showed peak flight activity occurs between 7:00–11:00 AM, with no nighttime activity. Phototaxis tests revealed females are highly sensitive to 360 nm, 380 nm, and 700 nm wavelengths, while males exhibit high sensitivity to 360 nm and 400 nm. This work enhances knowledge on the integration of visual and olfactory sensory information in beetles for host location and non-host avoidance. Full article

This study evaluates the effectiveness of transfer learning with pre-trained convolutional neural networks (CNNs) for the automated binary classification of surgical suture quality (high-quality/low-quality) using photographs of three suture types: interrupted open vascular sutures (IOVS), continuous over-and-over open sutures (COOS), and interrupted laparoscopic sutures (ILS). To address the challenge of limited medical data, eight state-of-the-art CNN architectures—EfficientNetB0, ResNet50V2, MobileNetV3Large, VGG16, VGG19, InceptionV3, Xception, and DenseNet121—were trained and validated on small datasets (100–190 images per type) using 5-fold cross-validation. Performance was assessed using the F1-score, AUC-ROC, and a custom weighted stability-aware score (Score_adj). The results demonstrate that transfer learning achieves robust classification (F1 > 0.90 for IOVS/ILS, 0.79 for COOS) despite data scarcity. ResNet50V2, DenseNet121, and Xception were more stable by Score_adj, with ResNet50V2 achieving the highest AUC-ROC (0.959 ± 0.008) for IOVS internal view classification. GradCAM visualizations confirmed model focus on clinically relevant features (e.g., stitch uniformity, tissue apposition). These findings validate transfer learning as a powerful approach for developing objective, automated surgical skill assessment tools, reducing reliance on subjective expert evaluations while maintaining accuracy in resource-constrained settings. Full article

Lepidoptera typically exhibit a dichotomy in compound eye design: diurnal butterflies possess apposition eyes for high resolution in bright light, whereas nocturnal moths have superposition eyes for enhanced sensitivity under dim conditions. However, exceptions, particularly among diurnal moths, challenge this pattern and offer insights into the evolution of compound eyes in Lepidoptera. In this study, we investigated the compound eye design of the diurnal moth Histia flabellicornis (Fabricius) using light, scanning, and transmission electron microscopy to determine whether it has superposition or apposition eyes, and to quantitatively analyze the structural features and visual acuity. Our results reveal that H. flabellicornis possesses apposition-type compound eyes composed of over 2000 ommatidia, each comprising a cornea, a crystalline cone, nine retinula cells forming a fused rhabdom, and a few isolated tracheoles. The calculated interommatidial angles (Δϕ = 4.08°) and the eye parameter P (P = 1.74) suggest a visual system adapted to moderate light conditions, balancing spatial resolution with photon capture. These findings confirm the presence of apposition eyes in H. flabellicornis, supporting the moth’s adaptation to diurnal behavior and contributing to understanding the evolutionary diversification of compound eye designs in Lepidoptera. Full article

Background: Venous sinus stenting is a promising treatment for intracranial venous disorders, such as idiopathic intracranial hypertension and pulsatile tinnitus, associated with transverse sinus stenosis. The VIVA Stent System (VSS) is a novel self-expanding braided venous stent designed to navigate tortuous cerebral venous anatomy. This preclinical study assessed the safety, thrombogenicity, and performance of the VSS in a swine model. Methods: Fifteen swine underwent bilateral internal mammary vein stenting with either the VSS (n = 9) or the PRECISE^® PRO RX stent (n = 6, reference). Fluoroscopy and thrombogenicity assessments were conducted on the day of stenting, clinical pathology analysis was carried out throughout the in-life phase, and CT Venography was performed before sacrifice. Animals were sacrificed at 30 ± 3 or 180 ± 11 days post-stenting for necropsy and histological evaluation. Results: Fluoroscopic angiography confirmed the successful VSS deployment with complete venous wall apposition and no vessel damage. The VSS achieved the highest scores on a four-point Likert scale for most performance parameters. No thrombus formation was observed on either delivery system. CT Venography confirmed vessel patency, no stent migration, and complete stent integrity. Histopathology showed a mild, expected foreign body reaction at 30 days, which resolved by 180 days, indicating normal healing progression. Both stents showed increased luminal diameter and decreased wall thickness at 180 days, suggesting vessel recovery. No adverse reactions were observed in non-target organs. Conclusions: The VSS exhibited favorable safety, procedural performance, and thromboresistance in a swine model, supporting its potential clinical use for treating transverse sinus stenosis and related conditions. Full article

Pollinating fig wasps (Agaonidae) engage in an obligate mutualism with Ficus species, which is mediated by host-specific chemical cues. However, the role of visual perception in host recognition remains poorly understood, particularly because of a lack of structural studies of their compound eyes. We investigated the ocular morphology of female Ceratosolen gravelyi (exclusive pollinator of F. semicordata) using scanning/transmission electron microscopy. The oval apposition eyes contain 228–263 ommatidia, which are asymmetrically distributed between the left and right eyes. Each ommatidium comprises a biconvex corneal lens overlying a tetrapartite eucone crystalline cone; proximal cone cells reveal an interlaced labyrinth. Pigment cells encapsulate each ommatidium, and numerous pigment granules and mitochondria are present in both pigment and retinular cells. Nine retinular cells comprise a unit, with eight photoreceptors (R1–R8) forming the rhabdom from the cone base to the basal matrix; a ninth cell replaces R8 in the apical third of the rhabdom. Optical metrics, including F-number (1.1°), acceptance angle (10.0°), and ommatidial sensitivity (0.26 µm²/sr), indicate diurnal activity in bright environments. These adaptations suggest that their eyes are critical for processing visual cues during host interactions, which advances our understanding of multimodal sensory integration in fig–wasp mutualism. Full article

Odontogenesis, the development of teeth, is a complex, multistage process that unfolds from early embryogenesis through tooth eruption and maturation. It serves as a classical model of organogenesis due to the intricate reciprocal interactions between cranial neural crest-derived mesenchyme and oral epithelium. This narrative review synthesizes current scientific knowledge on human tooth development, tracing the journey from the embryological origins in the first branchial arch to the formation of a fully functional tooth and its supporting structures. Key morphogenetic stages—bud, cap, bell, apposition, and root formation—are described in detail, highlighting the cellular events and histological features characterizing each stage. We discuss the molecular and cellular regulatory networks that orchestrate odontogenesis, including the conserved signaling pathways (Wnt, BMP, FGF, SHH, EDA) and transcription factors (e.g., PAX9, MSX1/2, PITX2) that drive tissue patterning and cell differentiation. The coordinated development of supporting periodontal tissues (cementum, periodontal ligament, alveolar bone, gingiva) is also examined as an integral part of tooth organogenesis. Finally, developmental anomalies (such as variations in tooth number, size, and form) and the fate of residual embryonic epithelial cells are reviewed to underscore the clinical significance of developmental processes. Understanding the normal course of odontogenesis provides crucial insight into congenital dental disorders and lays a foundation for advances in regenerative dental medicine. Full article

Background: The impact of exogenous explicit knowledge on early motor learning is highly variable and may be influenced by excitability within the procedural sensorimotor network. Recent transcranial magnetic stimulation (TMS) studies suggest that variability in interneuron recruitment by anterior–posterior (AP) currents is linked to differences in functional connectivity between premotor and motor regions. Objectives: This study used controllable pulse parameter TMS (cTMS) to assess how AP-sensitive interneuron excitability interacts with explicit knowledge to influence motor learning. Methods: Seventy-two participants were grouped as AP-positive (n = 36) and AP-negative groups (n = 36) based on whether an AP threshold could be obtained before reaching maximal stimulator output. A narrow (30 µs) stimulus was employed to target the longest latency corticospinal inputs selectively. Participants then practiced a continuous visuomotor tracking task and completed a delayed retention test. Half of each group received explicit knowledge of a repeated sequence embedded between random sequences. Random sequence tracking performance assessed general sensorimotor efficiency; repeated sequence performance assessed sequence-specific learning. Results: Both AP₃₀-positive participants, with and without explicit knowledge, and the AP₃₀-negative without explicit knowledge demonstrated similar improvements in sensorimotor efficiency driven by offline consolidation. However, AP₃₀-negative participants given explicit instruction exhibited significantly reduced improvement in sensorimotor efficiency, primarily due to impaired offline consolidation. Conclusions: These findings suggest that individuals with low excitability in long-latency AP-sensitive inputs may be more vulnerable to interference from explicit instruction. The current results highlight the importance of accounting for individual differences in interneuron excitability when developing instructional strategies for motor learning. Full article

(1) Background: Condylar fracture healing pattern classification in children and adolescents is primarily based on the radiological assessment of condylar morphology; however, recent studies showed the presence of a poor correlation between post-treatment radiological findings and clinical temporomandibular joint (TMJ) dysfunction. The present case series aimed to correlate the condylar morphology, shape, and trabecular bone density with the skeletal asymmetry and the clinical recovery of two growing patients with unilateral condylar fractures undergoing orthopedic treatment with the Balters Bionator appliance. (2) Methods: Pre- and post-treatment (12 months) cone-beam computed tomography (CBCT) scans of two growing patients with unilateral condylar fracture were retrieved; both patients were treated with the Balters Bionator appliance for one year. Morphological evaluation of the condylar healing pattern was carried out on CBCT reconstructions of the mandible. Condylar remodeling and skeletal asymmetry were assessed through linear measurements performed on pre- and post-treatment CBCT scans; then, fractal analysis (FA) was employed to assess the condylar trabecular bone density on orthopantomographies (OPTs). Clinical and TMJ functional evaluation were retrieved from patients’ records from before and at the end of the treatment (12 months). (3) Results: Conservative treatment of condylar fractures in growing patients led to an increased bone density of the condylar heads, regardless of the post-treatment size and morphology of the injured condyles. Patient one presented an unchanged condylar morphology on the affected side, while patient two’s condyle was slightly spherical. The qualitative results were confirmed by quantitative measurements on CBCTs. The radiological healing patterns were associated with slightly different functional outcomes. Both patients also exhibited an improvement in skeletal asymmetry and TMJ function. (4) Conclusions: According to the findings in the present study, the condylar remodeling and bone apposition after conservative treatment of condylar fractures in growing patients can exhibit different radiological and functional outcomes. Indeed, an unchanged morphology of the condylar head is more likely to determine a physiological TMJ recovery. Full article

Background/Objectives: Excessive occlusal forces manifest in bruxism and have consequences on teeth and jaws. The aim of this study was to determine the association of bruxism with clinical and radiological signs of excessive occlusal forces, such as tooth wear, fatigue dental fissures and fractures, abfraction, masseter muscle hypertrophy, and bone apposition at the mandibular angle. Methods: This cross-sectional clinical study included 181 patients presented for treatment in a general dentistry clinic. For each patient, data were extracted from the dental chart, as follows: demographic data (sex, age, and smoking), clinical data (number of teeth present, Eichner edentulous score, TWI wear score, number of fractured teeth, number of teeth with abfraction, presence of masseter hypertrophy, presence of hypersensitivity), and radiological data (bone apposition at the mandibular angle). The patients were divided into two groups according to the presence or absence of bruxism. A binomial logistic regression model was run to determine the association between bruxism and clinical and radiological signs of excessive occlusal forces. The data were statistically processed in SPSS. Results: In total, 99 women and 82 men with mean age 44.87 ± 12.67 were included in the study. Compared to the group without bruxism, the group of patients with bruxism (39.78%) showed statistically significant higher tooth wear index (TWI) (p < 0.0005), a higher number of fractured teeth (p = 0.037), a higher number of teeth with abfraction lesions (p = 0.001), and a significantly higher bone apposition score (p < 0.0005). The binomial logistic regression model showed a high prediction bruxism score for masseter muscle hypertrophy (15 times, p < 0.0005), for tooth wear index (almost 7 times, p = 0.010), and for bone apposition score (almost 3 times, p = 0.044). Conclusions: Patients with bruxism showed masseter muscle hypertrophy, higher attrition-type tooth wear index, and more teeth with fatigue fractures and abfractions than those without bruxism. Bruxism clinical signs were positively correlated with a higher bone apposition score. Full article

Trilobites, as typical euarthropods, possess compound eyes. In 1901, Lindström was the first to describe them in detail; on the one hand, we reconsider his descriptions of the different modes of trilobite eyes; on the other hand, we expand this by compiling the observations that have been possible in recent years. There are two, perhaps three kinds of trilobite compound eyes. The first are the primordial holochroal eyes, which are actually apposition compound eyes, similar to those of many modern diurnal crustaceans and insects. The abathochroal eyes, often referred to as the second form, are probably a subtype of the holochroal eyes. Consequently, the second is the schizochroal eye of phacopid trilobites, which are hyper-compound eyes composed of numerous small compound eyes below each of the big lenses, which appear from outside as one big lateral eye each. Thirdly, one may call the maculae light-sensitive organs, but this is still uncertain. Comparing what are probably the oldest trilobite eyes described so far with other forms, it is possible to conclude that the sensory apparatus is much older than the fossil record of trilobite eyes and probably developed in Precambrian times. The refractive apparatus, however, was developed later and separately within the systematic groups. This explains why, for example, the mandibulates have a lens and a crystalline cone. Still, the chelicerate xiphosurans, such as horseshoe crabs or eurypterids, possess a lens cylinder with an index gradient but no crystalline cone. Furthermore, this can explain why the calcite character of trilobites is unique in the arthropod kingdom. An important discovery is the probably epidermal, lens-building cells encompassing a prospective lens of Schmidtiellus reetae Bergström 1973 from the early Lower Cambrian of Estonia. We reconsider the morphology of hypostome maculae and interpret them as a potential phylogenetic relict and a potential predecessor of all arthropod ommatidial compound eyes. It will be of great relevance for future research to understand the evolution of compound eyes and vision because we witness the emergence of the first lenses in the trilobite, if not the arthropod kingdom. Full article

Bone substitutes are commonly used in bone regeneration, and their functionalization with bioactive molecules can significantly enhance bone regeneration by directly influencing bone cells. This study aimed to evaluate the potential of raloxifene-functionalized Cerabone^® (CB) for promoting bone repair and to highlight the implications in bone regeneration. The effectiveness of Cerabone^® functionalized with raloxifene via sonication or gel delivery in promoting bone repair in rat calvaria defects was assessed. Ninety-six male rats with critical-sized calvarial defects were divided into six treatment groups (n = 16): COAG (spontaneous blood clot), CB (Cerabone^®), CBS (Cerabone^® sonicated alone), CBRS (Cerabone^® with raloxifene sonicated), CBG (Cerabone^® with gel vehicle), and CBRG (Cerabone^® with 20% raloxifene gel). After 14 and 28 days, samples were analyzed using microtomography, histomorphometry, immunohistochemistry, and fluorescence techniques. Quantitative data were statistically analyzed, comparing each group to the control CB group with significance set at p < 0.05. Micro-CT analysis demonstrated a significant increase in bone volume in the CBRS, CBRG, and CBS groups at 28 days compared to the CB group (p < 0.05). Specifically, the mean bone volume percentages for the CBRS, CBRG, CBS, and CB groups were 21.18%, 17.51%, 13.18%, and 7.8%, respectively. Histomorphometry showed increased new bone formation in the CBRS and CBRG groups at both 14 and 28 days. Fluorescence analysis revealed a significantly higher daily mineral apposition rate in the CBRS and CBRG groups at 28 days. These findings suggest that raloxifene-functionalized CB, delivered via sonication or gel, significantly enhances bone repair by improving bone volume and mineralization, highlighting its potential as an effective strategy for bone regeneration. Full article

Neck and lower back pain, often caused by spinal disorders such as scoliosis and degenerative disc disease, affects over 80% of the global population, with an estimated from 250,000 to 500,000 spinal cord injuries occurring annually according to the WHO. As the demand for spinal procedures continues to rise, advancements in implant materials have become essential. Orthopedic implants play a vital role in restoring mobility and improving the quality of life of patients with musculoskeletal disorders. Metallic implants, such as stainless steel, titanium, and its alloys, are commonly used to make fixation devices for spinal fusion surgery due to their excellent mechanical properties. However, complications such as stress shielding have been recorded. Polymeric materials offer new prospects as an alternative to metal-based materials such as those based on Polyaryletherketone (PEAK). Among the advanced materials used in these implants, PAEK has emerged as the preferred choice due to its exceptional mechanical strength, thermal stability, and chemical resistance. Polyetheretherketone (PEEK) and Polyetherketoneketone (PEKK) offer notable advantages, such as radiolucency and mechanical properties resembling those of natural bone, reducing stress shielding and facilitating postoperative imaging. Although PEEK and PEKK are considered as bioinert, it has been demonstrated that adding bioactive agents such as hydroxyapatite (HA) into the matrix to make composites solves this problem and can help with aiding direct bone apposition. Furthermore, PAEK’s compatibility with 3DP enables the creation of patient-specific implants with intricate geometries, enhancing the surgical outcomes. In addition, the lattice structures of orthopedic implants can alleviate stress shielding, provide an enhanced surface area for the release of bioactive agents (or antimicrobial materials), and eliminate more imaging artifacts compared to that of simple, solid metal implants. PAEK/HA composite implants represent a transformative solution, addressing the psychological, social, and economic burdens of spinal disorders, while enhancing the surgical outcomes. With continuous technological evolution, PAEK/HA composites are poised to play a pivotal role in modern spinal care. Full article

Estrogen deficiency, coupled with a cafeteria diet (CD), can impair peri-implant bone repair, posing a significant challenge to implant success in affected individuals. Thus, it is crucial to explore strategies for implant functionalization and systemic treatments that could alleviate these bone alterations. This study aimed to assess peri-implant bone repair in ovariectomized (OVX) rats subjected to a CD, with a focus on implants functionalized with genistein (GEN), compared to conventional implants (CONV), and the effects of systemic treatment with risedronate sodium (RIS). In total, thirty-six female rats were assigned to three groups: rats with estrogen (SHAM), rats with estrogen deficiency and CD (OVX-CD), rats with estrogen deficiency, CD, and systemic RIS treatment (OVX-CD-RIS). All rats underwent bilateral extraction of the first upper molars followed by implant installation. Each group was further subdivided based on implant type: conventional implants (CONV) or GEN-functionalized implants, resulting in six subgroups (n = 6). The study employed several analyses, including reverse torque testing, microcomputed tomography (Micro-CT), epifluorescence microscopy, and molecular assays. The main result demonstrated that the OVX-CD-RIS/GEN subgroup exhibited significantly higher reverse torque values, indicating stronger implant stability. Micro-CT scans revealed a greater bone volume in the OVX-CD-RIS/GEN subgroup compared to other subgroups. Epifluorescence microscopy also demonstrated an increased mineral apposition rate in both the OVX-CD/GEN and OVX-CD-RIS/GEN subgroups. Molecular analysis indicated elevated expression levels of osteocalcin, alkaline phosphatase, and vascular endothelial growth factor in the OVX-CD-RIS/GEN subgroup. In conclusion, the combined treatment of systemic RIS and GEN-functionalized implants significantly enhanced peri-implant bone repair, offering a promising strategy to improve implant outcomes in postmenopausal women with metabolic syndrome. Full article

The alveolar ridge undergoes a loss in volume and atrophy after tooth extraction. Understanding the wound healing and bone regeneration process after tooth extraction is a key factor in the insertion of dental implants. Therefore, the aim of the present study was to analyze the socket healing process after the extraction of upper premolars based on cone beam computed tomography (CBCT) over six months. Special focus was placed on the morphological changes in the alveolar crest and within the socket. A retrospective analysis of patients in need of tooth extraction in the upper premolar region was performed in this study. All patients received flapless tooth extraction under local anesthesia and CBCT immediately after tooth extraction. Further CBCT analysis was performed after three months for the first group (n = 18) and after six months for the second group (n = 18). The results showed that all sockets underwent an inward movement of the defect walls towards the defect center, resulting in reduced total alveolar ridge volume and defect volume. This result was observed after three months and persisted after six months. The inward movement was quantified as a vertical socket collapse of up to 30.1 ± 9.0% after three months and 34.3 ± 6.7% after six months. The horizontal inward movement was quantified as a buccal socket collapse of 47.7 ± 12.3% after three months and 55.7 ± 29.1% after six months. New bone formation within the socket was evident, especially in the occlusal part of the socket. Additionally, bone formation was primarily observed as bone apposition along the socket walls and did not reach the defect center in most cases. The combination of socket collapse and bone apposition led to the formation of cavitations inside the socket that were mostly localized under the occlusal part. These novel findings with respect to socket collapse and formation of cavitation represent a paradigm shift and call for reconsidering the current understanding of socket healing. Based on the data, socket healing should be understood as a patient-specific process that requires 3D radiographic analysis for planning dental implants. Full article