Investigating Ras homolog gene family member C (RhoC) and Ki67 expression following external beam radiation therapy show increased RhoC expression in relapsing prostate cancer xenografts.

Ras homolog gene family member C (RhoC) is a GTPase involved in cell migration, implicated in epithelial-mesenchymal transition and treatment resistance and metastasis of cancer. For example, RhoC has been shown to be involved in resistance to radiation in cervical carcinoma. Here, the effect of X-ray irradiation on RhoC expression in prostate cancer (PCa) xenografts was investigated in both xenografts in regression and relapse. Male BALB/cAnNRj-Foxn1nu/nu mice were inoculated with 4-6 million LNCaP-FGC cells and established xenografts were irradiated with X-rays (200 kV, 1 Gymin-1), 5, 10 or 15 Gy using a Gulmay Medical X-ray system. Expression of RhoC and Ki67, a known proliferation marker, was investigated in xenografts, given 15 Gy, 7 days (midst response as measured by size) or 3 weeks (relapse) post irradiation. Staining was quantified using the Halo software (v2.3.2089.34) with the Indica Labs - cytonuclear v1.6 algorithm. RhoC and Ki67 staining was divided into weak, medium, and strong staining and the percentage of cells stained, single and dual staining, was quantified. The HALO software was further used to classify the tissue in each section so that analysis of RhoC and Ki67 expression in cancer cells, stroma and necrotic areas could be done separately. The results showed that RhoC expression in cancer and stroma cells was significantly higher in relapsed xenografts than in those in regression. This was not seen for Ki67 staining, where the percentage of stained cells were the same in regressing and relapsing tumors. RhoC could be a useful biomarker to confirm relapse following external beam radiation therapy.

Vessel-targeted compensation of deformable motion in interventional cone-beam CT.

The present standard of care for unresectable liver cancer is transarterial chemoembolization (TACE), which involves using chemotherapeutic particles to selectively embolize the arteries supplying hepatic tumors. Accurate volumetric identification of intricate fine vascularity is crucial for selective embolization. Three-dimensional imaging, particularly cone-beam CT (CBCT), aids in visualization and targeting of small vessels in such highly variable anatomy, but long image acquisition time results in intra-scan patient motion, which distorts vascular structures and tissue boundaries. To improve clarity of vascular anatomy and intra-procedural utility, this work proposes a targeted motion estimation and compensation framework that removes the need for any prior information or external tracking and for user interaction. Motion estimation is performed in two stages: (i) a target identification stage that segments arteries and catheters in the projection domain using a multi-view convolutional neural network to construct a coarse 3D vascular mask; and (ii) a targeted motion estimation stage that iteratively solves for the time-varying motion field via optimization of a vessel-enhancing objective function computed over the target vascular mask. The vessel-enhancing objective is derived through eigenvalues of the local image Hessian to emphasize bright tubular structures. Motion compensation is achieved via spatial transformer operators that apply time-dependent deformations to partial angle reconstructions, allowing efficient minimization via gradient backpropagation. The framework was trained and evaluated in anatomically realistic simulated motion-corrupted CBCTs mimicking TACE of hepatic tumors, at intermediate (3.0 mm) and large (6.0 mm) motion magnitudes. Motion compensation substantially improved median vascular DICE score (from 0.30 to 0.59 for large motion), image SSIM (from 0.77 to 0.93 for large motion), and vessel sharpness (0.189 mm-1 to 0.233 mm-1 for large motion) in simulated cases. Motion compensation also demonstrated increased vessel sharpness (0.188 mm-1 before to 0.205 mm-1 after) and reconstructed vessel length (median increased from 37.37 to 41.00 mm) on a clinical interventional CBCT. The proposed anatomy-aware motion compensation framework presented a promising approach for improving the utility of CBCT for intra-procedural vascular imaging, facilitating selective embolization procedures.

CT in musculoskeletal imaging: still helpful and for what?

Computed tomography (CT) is a common modality employed for musculoskeletal imaging. Conventional CT techniques are useful for the assessment of trauma in detection, characterization and surgical planning of complex fractures. CT arthrography can depict internal derangement lesions and impact medical decision making of orthopedic providers. In oncology, CT can have a role in the characterization of bone tumors and may elucidate soft tissue mineralization patterns. Several advances in CT technology have led to a variety of acquisition techniques with distinct clinical applications. These include four-dimensional CT, which allows examination of joints during motion; cone-beam CT, which allows examination during physiological weight-bearing conditions; dual-energy CT, which allows material decomposition useful in musculoskeletal deposition disorders (e.g., gout) and bone marrow edema detection; and photon-counting CT, which provides increased spatial resolution, decreased radiation, and material decomposition compared to standard multi-detector CT systems due to its ability to directly translate X-ray photon energies into electrical signals. Advanced acquisition techniques provide higher spatial resolution scans capable of enhanced bony microarchitecture and bone mineral density assessment. Together, these CT acquisition techniques will continue to play a substantial role in the practices of orthopedics, rheumatology, metabolic bone, oncology, and interventional radiology.

In vitro Accuracy of Ultra-Low Dose Cone-Beam Computed Tomography for Detection of Proximal Caries.

OBJECTIVES: This study aimed to assess the accuracy of ultra-low dose (ULD) cone-beam computed tomography (CBCT) for detection of proximal caries. METHODS: This in vitro study evaluated 104 molar and premolar teeth. The teeth were mounted in dry skulls and underwent CBCT with four protocols of high-resolution (HR), normal (NORM), ULD-HR, and ULD-NORM; 78 CBCT images were scored by three observers for presence and penetration depth of caries twice with a 2-week interval using a 5-point Likert scale. The teeth were then sectioned and observed under a stereomicroscope (gold standard). The four protocols were compared with each other and with the gold standard. The receiver operating characteristic (ROC) curve was drawn, and the area under the curve (AUC) was calculated and compared by the Chi-square test (alpha = 0.05). RESULTS: The interobserver agreement ranged from 0.5233 to 0.6034 for ULD-NORM, 0.5380 to 0.6279 for NORM, 0.5856 to 0.6300 for ULD-HR, and 0.6614 to 0.7707 for HR images. The intra-observer agreement ranged from 0.6027 to 0.8812 for ULD-HR, 0.7083 to 0.7556 for HR, 0.6076 to 0.9452 for ULD-NORM, and 0.7012 to 0.9221 for NORM images. Comparison of AUC revealed no significant difference between NORM and ULD-NORM (P > 0.05), or HR and ULD-HR (P > 0.05). The highest AUC belonged to HR (0.8529) and the lowest to NORM (0.7774). CONCLUSIONS: Considering the significant reduction in radiation dose in ULD CBCT and its acceptable diagnostic accuracy for detection of proximal caries, this protocol may be used for detection of proximal carious lesions and assessment of their depth.

Patient-specific quality assurance of dynamically-collimated proton therapy treatment plans.

BACKGROUND: The dynamic collimation system (DCS) provides energy layer-specific collimation for pencil beam scanning (PBS) proton therapy using two pairs of orthogonal nickel trimmer blades. While excellent measurement-to-calculation agreement has been demonstrated for simple cube-shaped DCS-trimmed dose distributions, no comparison of measurement and dose calculation has been made for patient-specific treatment plans. PURPOSE: To validate a patient-specific quality assurance (PSQA) process for DCS-trimmed PBS treatment plans and evaluate the agreement between measured and calculated dose distributions. METHODS: Three intracranial patient cases were considered. Standard uncollimated PBS and DCS-collimated treatment plans were generated for each patient using the Astroid treatment planning system (TPS). Plans were recalculated in a water phantom and delivered at the Miami Cancer Institute (MCI) using an Ion Beam Applications (IBA) dedicated nozzle system and prototype DCS. Planar dose measurements were acquired at two depths within low-gradient regions of the target volume using an IBA MatriXX ion chamber array. RESULTS: Measured and calculated dose distributions were compared using 2D gamma analysis with 3%/3 mm criteria and low dose threshold of 10% of the maximum dose. Median gamma pass rates across all plans and measurement depths were 99.0% (PBS) and 98.3% (DCS), with a minimum gamma pass rate of 88.5% (PBS) and 91.2% (DCS). CONCLUSIONS: The PSQA process has been validated and experimentally verified for DCS-collimated PBS. Dosimetric agreement between the measured and calculated doses was demonstrated to be similar for DCS-collimated PBS to that achievable with noncollimated PBS.

AAPM WGTG51 Report 385: Addendum to the AAPM's TG-51 protocol for clinical reference dosimetry of high-energy electron beams.

An Addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water is presented for electron beams with energies between 4 MeV and 22 MeV ( 1.70 cm ≤ R 50 ≤ 8.70 cm $1.70\nobreakspace {\rm cm} \le R_{\text{50}} \le 8.70\nobreakspace {\rm cm}$ ). This updated formalism allows simplified calibration procedures, including the use of calibrated cylindrical ionization chambers in all electron beams without the use of a gradient correction. New k Q $k_{Q}$ data are provided for electron beams based on Monte Carlo simulations. Implementation guidance is provided. Components of the uncertainty budget in determining absorbed dose to water at the reference depth are discussed. Specifications for a reference-class chamber in electron beams include chamber stability, settling, ion recombination behavior, and polarity dependence. Progress in electron beam reference dosimetry is reviewed. Although this report introduces some major changes (e.g., gradient corrections are implicitly included in the electron beam quality conversion factors), they serve to simplify the calibration procedure. Results for absorbed dose per linac monitor unit are expected to be up to approximately 2 % higher using this Addendum compared to using the original TG-51 protocol.

A Comparative Evaluation of the Efficiencies of Different Rotary File Systems in Terms of Remaining Dentin Thickness Using Cone Beam Computed Tomography: An In Vitro Study.

AIM: The aim of this study was to evaluate and compare the dentin thickness of the mesio-buccal canal of the lower first molar after canal preparation with three different rotary file systems using cone beam computed tomography (CBCT). METHODOLOGY: TruNatomy (Dentsply Sirona, USA), 2Shape (Micro-Mega, France), and One Curve (Micro-Mega, France) were the three different rotary files that were employed. A total of 45 excised human permanent first mandibular molars were divided into Groups A (TruNatomy), B (2Shape), and C (One Curve) at random. To measure the residual dentin thickness at 3 mm, 5 mm, and 7 mm from the radiographic apex, the mesial root of the tooth was removed from the tooth, and a mesio-buccal canal was taken. Samples were mounted in clear acrylic resin and were subjected to a pre-instrumentation CBCT scan. The mesio-buccal canal was cleaned and shaped while maintaining the final mesio-buccal canal preparation of Group A - 26/0.04, Group B - 25/0.04, and Group C - 25/0.04. The samples were extensively irrigated with 3% sodium hypochlorite and 17% EDTA, and a post-instrumentation scan was performed on them. Statistics were used to determine the values from CBCT scans that were recorded for pre- and post-instrumentations. RESULTS: The results showed that Group A had the greatest drop in dentin thickness, followed by Group B and Group C. The change in dentin thickness was greatest at 3 mm and 7 mm. CONCLUSION: In contrast to TruNatomy and 2Shape rotary file systems, One Curve has the advantage of maintaining a tooth's thickness at 3 and 7 millimeters from the radiological apex. Since the TruNatomy file system removes more dentin than the other two combined, it should be used cautiously. Choosing the right instrument is crucial for cleaning and shaping during root canal preparation.

Comparison of clinical outcome between surgical treatment and particle beam therapy for pelvic bone sarcomas: A retrospective multicenter study in Japan.

BACKGROUND: Few studies have compared the clinical outcomes of patients with pelvic bone sarcomas treated surgically and those treated with particle beam therapy. This is a multicenter retrospective cohort study which compared the clinical outcomes of patients with pelvic bone sarcoma who underwent surgical treatment and particle beam therapy in Japan. METHODS: A total of 116 patients with pelvic bone sarcoma treated at 19 specialized sarcoma centers in Japan were included in this study. Fifty-seven patients underwent surgery (surgery group), and 59 patients underwent particle beam therapy (particle beam group; carbon-ion radiotherapy: 55 patients, proton: four patients). RESULTS: The median age at primary tumor diagnosis was 52 years in the surgery group and 66 years in the particle beam group (P < 0.001), and the median tumor size was 9 cm in the surgery group and 8 cm in the particle beam group (P = 0.091). Overall survival (OS), local control (LC), and metastasis-free survival (MFS) rates were evaluated using the Kaplan-Meier method and compared among 116 patients with bone sarcoma (surgery group, 57 patients; particle beam group, 59 patients). After propensity score matching, the 3-year OS, LC, and MFS rates were 82.9% (95% confidence interval [CI], 60.5-93.2%), 66.0% (95% CI, 43.3-81.3%), and 78.4% (95% CI, 55.5-90.5%), respectively, in the surgery group and 64.9% (95% CI, 41.7-80.8%), 86.4% (95% CI, 63.3-95.4%), and 62.6% (95% CI, 38.5-79.4%), respectively, in the particle beam group. In chordoma patients, only surgery was significantly correlated with worse LC in the univariate analysis. CONCLUSIONS: The groups had no significant differences in the OS, LC, and MFS rates. Among the patients with chordomas, the 3-year LC rate in the particle beam group was significantly higher than in the surgery group.

Cone beam computed tomography and cross-sectional anatomy of the region of the fetlock in the horse (Equus caballus).

This study aimed to delineate the detailed anatomy of the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints in healthy horses using cone beam computed tomography (CBCT). The fetlock region of 15 cadaveric forelimbs and 14 cadaveric hindlimbs from nine adult horses without orthopaedic disease underwent CBCT scanning. Additionally, arthrography CBCT scans were conducted following intra-articular injection of a radiopaque contrast medium containing blue epoxy resin dye. Subsequently, limbs were frozen and sectioned to visualize anatomical structures in sectional planes corresponding to selected CBCT images. CBCT proved suitable for detailed visualization of the bony components of the fetlock region. Furthermore, the common digital extensor tendon, superficial and deep digital flexor tendons, suspensory ligament, and straight and oblique sesamoidean ligaments were identifiable on CBCT images. However, certain ligaments, such as the collateral sesamoidean ligaments and intersesamoidean ligaments, were not clearly identified. The hyaline cartilage of the MCP and MTP joint facets was assessable on the post-contrast sequence. In cases where a radiographic or ultrasound examination cannot provide a definitive diagnosis and determine the extent of disease, CBCT can provide additional valuable data on the equine MCP and MTP joint. The images obtained in this study can serve as a reference for CBCT examination of the equine MCP and MTP joint.

A rotating beam-blocker method for cone beam CT scatter correction.

BACKGROUND: Cone beam CT (CBCT) is widely utilized in clinics. However, the scatter artifact degrades the CBCT image quality, hampering the expansion of CBCT applications. Recently, beam-blocker methods have been used for CBCT scatter correction and proved their high cost-effectiveness. PURPOSE: A rotating beam-blocker (RBB) method for CBCT scatter correction was proposed to complete scatter correction and image reconstruction within a single scan in both full- and half-fan scan scenarios. METHODS: The RBB consisted of two open regions and two blocked regions, and was designed as a centrosymmetric structure. The open and blocked projections could be alternatively obtained within one single rotation. The open projections were corrected with the scatter signal calculated from the blocked projections, and then used to reconstruct the 3D image via the Feldkamp-Davis-Kress algorithm. The performance of the RBB method was evaluated on head and pelvis phantoms in scenarios with and without a bowtie filter. The images obtained from nine repeated scans in each scenario were used to calculate the evaluation metrics including the CT number error, spatial nonuniformity (SNU) and contrast-to-noise ratio (CNR). RESULTS: For the head phantom, the CT number error was decreased to <5 after scatter correction from >200 HU before correction when scanned without a bowtie filter, and to <4 from >160 HU when scanned with a full bowtie filter. For the pelvis phantom, the CT number error was reduced to <12 after scatter correction from >250 HU before correction when scanned without a bowtie filter, and to <10 from >190 HU when scanned with a half bowtie filter. After scatter correction, the uniformity and contrast were both improved, resulting in an SNU of >79% decrease and CNR of >2 times increase, respectively. CONCLUSIONS: High-quality CBCT images could be obtained in a single scan after using the proposed RBB method for scatter correction, enabling more accurate image guidance for surgery and radiation therapy applications. With almost no time delay between the successive open and blocked projections, the RBB method could eliminate the motion-induced anatomical mismatches between the corresponding open and blocked projections and could find particular usefulness in thoracic and abdominal imaging.

Retrospective analysis of pathological changes in the maxillary sinus with CBCT.

The aim of this study is to examine the frequency of maxillary sinus pathologies and their relationship with each other using cone beam computed tomography (CBCT) and to make a new grade according to the number of affected walls. 1000 maxillary sinuses of 500 patients with CBCT images were included in the study. Anatomical variations and pathological formations of the maxillary sinuses were examined. Images were evaluated for the presence of flat, polypoidal, partial and generalized mucosal thickening, partial and total opacification, polyps and mucous retention cysts. Maxillary sinus pathologies were graded according to the number of walls affected. In the examined CBCT images, no pathology was found in 54.2% of the maxillary sinuses, while pathology was observed in 45.8%. The most common sinus pathologies were mucous retention cyst (12.3%) and polypoidal thickening (12.2%). While pneumatization, ostium obstruction, and the presence of sinus-related roots were associated with sinus pathology, no relationship was found with nasal septum deviation and the presence of septa. Before dental implant and sinus surgery applications, the presence of sinus pathologies and their relationship with anatomical variations can be evaluated with CBCT, a three-dimensional technique, and complications such as sinus membrane perforation, infection, failure to break the bone window due to the presence of antral septa, graft loss and oroantral fistula formation can be reduced.

[Study on the consistency between CBCT image features of sphenopalatine foramen and those seen in nasal endoscopy].

Objective:To study the clinical anatomy of the sphenopalatine foramina by dissecting the sphenopalatine foramina during Vidian nerve branch neurotomy. The anatomy and CBCT images of sphenopalatine foramen were analyzed to facilitate the navigational of clinical operation using CBCT images. Methods:From October 2017 to September 2023, 84 cases（168 sides） of Vidian nerve branch neurotomy in our department were collected. The clinical summary was made according to the anatomy of sphenopalatine foramen during the operation. Preoperative CBCT imaging findings of the sphenopalatine foramina were also studied. Results:The clinical anatomy of sphenopalatine foramen could be divided into four types: middle meatus type（1.19%）, trans-meatus type（62.29%）, superior meatus type（33.33%） and double foramen type（1.19%）. The incidence of ethmoidal ridge was 98.81%. The distance from sphenopalatine foramina to posterior nasal canal were（14.63±2.66） mm to left and（14.65±2.63） mm to right, The position Angle ∠a of lower margin of sphenopalatine foramina were（62.36±10.05）° to left and（61.51±11.82）° to right, respectively. Axial CT images can be used to divide the sphenopalatine foramen into five levels: the upper edge of the sphenopalatine foramen level, the Vidian nerve level, the basal plate interaction level, the lower edge of the sphenopalatine foramen level and the pterygopalatine canal level. The agreement between endoscopic anatomy of sphenopalatine foramen and imaging navigation was 100%. Conclusion:The sphenopalatine foramina exhibit various anatomical types. The preoperative navigational CBCT reading can effectively identify the type of sphenopalatine foramina, guide the choice of surgical method, and help avoid serious complications. This has significant clinical application value.

Recording and Revealing 2.5D Nanopatterned Hidden Information on Silk Protein Bioresists.

Nanopatterning on biomaterials has attracted significant attention as it can lead to the development of biomedical devices capable of performing diagnostic and therapeutic functions while being biocompatible. Among various nanopatterning techniques, electron-beam lithography (EBL) enables precise and versatile nanopatterning in desired shapes. Various biomaterials are successfully nanopatterned as bioresists by using EBL. However, the use of high-energy electron beams (e-beams) for high-resolutive patterning has incorporated functional materials and has caused adverse effects on biomaterials. Moreover, the scattering of electrons not absorbed by the bioresist leads to proximity effects, thus deteriorating pattern quality. Herein, EBL-based nanopatterning is reported by inducing molecular degradation of amorphous silk fibroin, followed by selectively inducing secondary structures. High-resolution EBL nanopatterning is achievable, even at low-energy e-beam (5 keV) and low doses, as it minimizes the proximity effect and enables precise 2.5D nanopatterning via grayscale lithography. Additionally, integrating nanophotonic structures into fluorescent material-containing silk allows for fluorescence amplification. Furthermore, this post-exposure cross-linking way indicates that the silk bioresist can maintain nanopatterned information stored in silk molecules in the amorphous state, utilizing for the secure storage of nanopatterned information as a security patch. Based on the fabrication technique, versatile biomaterial-based nanodevices for biomedical applications can be envisioned.

Evaluating the Anterior Loop of the Mental Nerve Using Cone Beam CT Scans in the Jordanian Population.

INTRODUCTION: Knowledge of anatomical landmarks is crucial for effective dental treatments, especially in surgical procedures. The mental nerve (MN), a branch of the inferior alveolar nerve, features a critical landmark known as the anterior loop (AL), often overlooked by surgeons. This study aims to assess the occurrence of the MN AL, its type, and its length within a sample of the Jordanian population by utilizing cone beam computed tomography (CBCT) scans. METHODS: This retrospective observational study included the acquisition of CBCT images from a total of randomly selected 268 patients who sought treatment for a range of dental conditions (such as tooth extraction, orthodontic therapy, and dental implants) at hospitals affiliated with the Jordanian Royal Medical Services. Reformatted images were utilized to detect the AL type, length, and the association between the nerve type and mental foramen (MF) position. RESULTS: This study involved 268 patients. The distribution of MF positions and the characteristics of the inferior dental nerve were evaluated, with no significant gender differences observed. The predominant location for the MF in both males and females in both sides was position IV, with 52% of females and 56-59% (left-right sides) of males presenting this trait. The inferior dental nerve types also showed no significant gender variation, with 42-43% (left-right sides) of females having type III and a similar distribution among males. Measurements of the midline-mental foramen and inter-foramen distances revealed slight variations between genders, with significant differences noted in the right AL length for type III nerves, favoring males (p=0.034). A notable correlation was found between the type of inferior dental nerve and the MF position, particularly with type I nerves predominantly associating with position IV mental foramina (p≤0.004). CONCLUSION: CBCT scans are essential in the precise evaluation of the AL, aiding in the prevention of nerve injuries during dental procedures. Our results highlight the diversity of the AL in the Jordanian population and the importance of individualized treatment plans. Future research with larger cohorts is advised to refine these insights, aiming to improve treatment outcomes and patient care.

Level set simulation of focused ion beam sputtering of a multilayer substrate.

The evolution of a multilayer sample surface during focused ion beam processing was simulated using the level set method and experimentally studied by milling a silicon dioxide layer covering a crystalline silicon substrate. The simulation took into account the redeposition of atoms simultaneously sputtered from both layers of the sample as well as the influence of backscattered ions on the milling process. Monte Carlo simulations were applied to produce tabulated data on the angular distributions of sputtered atoms and backscattered ions. Two sets of test structures including narrow trenches and rectangular boxes with different aspect ratios were experimentally prepared, and their cross sections were visualized in scanning transmission electron microscopy images. The superimposition of the calculated structure profiles onto the images showed a satisfactory agreement between simulation and experimental results. In the case of boxes that were prepared with an asymmetric cross section, the simulation can accurately predict the depth and shape of the structures, but there is some inaccuracy in reproducing the form of the left sidewall of the structure with a large amount of the redeposited material. To further validate the developed simulation approach and gain a better understanding of the sputtering process, the distribution of oxygen atoms in the redeposited layer derived from the numerical data was compared with the corresponding elemental map acquired by energy-dispersive X-ray microanalysis.

Proton beam therapy and dentofacial development in paediatric cancer patients: A scoping review.

Purpose: It is known that radiation to dentofacial structures during childhood can lead to developmental disturbances. However, this appears to be a relatively subordinated research subject. For this reason, this review aims to establish the current evidence base on the effect of PBT on dentofacial development in paediatric patients treated for cancer in the head and neck region. Materials and methods: A comprehensive search was undertaken to identify both published and unpublished studies or reports. A single reviewer completed initial screening of abstracts; 2 independent reviewers completed secondary screening and data extraction. A narrative synthesis was then conducted. Results: 82 records were screened in total, resulting in 11 included articles. These articles varied in terms of study design and reporting quality. Owing to both poor study reporting and limited patient numbers, it is not possible to determine the effect of cancer diagnosis, chronological age at treatment, radiation dose or treatment modality on the incidence of facial deformation or dental development anomalies. Conclusion: Disturbances in dentofacial development are an under-reported toxicity in paediatric cancer survivors treated with PBT to the head and neck. There is a need for more research on dentofacial toxicity reporting, focused on the impact of treatment age, radiation dose, concurrent therapies, and the subsequent impact on quality of life.

Atypical presentation of molluscum contagiosum infection in a human immunodeficiency virus-positive patient.

Molluscum contagiosum (MC) is a skin infection caused by a virus of the poxvirus family. The infection is usually innocuous and inconsequential, occasionally resolving spontaneously. It is rarely associated with such severe physical and psychological morbidity. The clinical lesions are usually painless papules or nodules with central umbilication. Painful anogenital tumors exhibiting a cerebriform surface have rarely been reported. MC infection in human immunodeficiency virus (HIV)-infected patients may present with generalized papules and papulonodules, and sometimes, progression to tumorous lesions. Early detection and effective treatment of the infection in HIV patients will go a long way in preventing progression to tumors, which are known to be resistant to treatment. The tumors responded well to X-ray external beam radiotherapy.

The Assessment of C-shaped Canal Prevalence in Mandibular Second Molars Using Endodontic Microscopy and Cone Beam Computed Tomography: An In Vivo Investigation.

Background Understanding root canal anatomy variations, particularly C-shaped canals, is crucial for successful endodontic treatment. This study used clinical and radiographic methods to assess the prevalence and characteristics of C-shaped canals in mandibular second molars in Western Maharashtra. Materials and methods This prospective study was conducted in the western region of Maharashtra, India. The samples included patients requiring endodontic treatment for mandibular second molars. Clinical evaluation was conducted using a surgical endodontic microscope and cone beam computed tomography (CBCT) imaging. Inclusion and exclusion criteria ensured the selection of a focused and homogeneous sample. Data analysis included assessment of unilateral/bilateral occurrence, canal distribution, and cross-sectional characteristics. Results Out of 200 mandibular second molars, 7.5% exhibited C-shaped root canals, with no significant gender differences. Canal distribution varied across coronal, middle, and apical levels, with prevalent configurations being C1, C2, C3, and C4. No significant differences were observed in canal distribution based on root levels. No significant gender differences were found in the presence of grooves on the root surfaces. Conclusion This study provides valuable insights into the prevalence and characteristics of C-shaped canals in mandibular second molars in Western Maharashtra. Further research into histological and genetic aspects can enhance our understanding, leading to improved treatment strategies for complex root canal anatomy variations.

Management of a bulbous blunderbuss maxillary central incisor with one root and three canals in a patient with cleft lip and palate.

Unique anatomical deviations in canal structure are rare in anterior teeth, especially central incisors, and thus risk being overlooked. For successful intervention, a meticulous diagnostic procedure and treatment plan, significantly aided by cone-beam computed tomography (CBCT), are crucial. The case at hand explores the management of a maxillary left central incisor in a cleft palate patient, characterized by multiple developmental lobes, a bulbous crown, and an atypical root anatomy. The primary symptom was pain, accompanied by a history of trauma at age 8 years and ensuing tooth discoloration. Initial evaluations, augmented by CBCT, revealed pulpal necrosis in a single-rooted tooth with three distinct canals. Initial clinical examination was supplemented by electrical pulp testing, RadioVisioGraphy (RVG), and CBCT, after which the root canal therapy was initiated. Informed consent was obtained from the patient. The access cavity preparation resulted in a three-orifice cavity. Subsequently, the canals were enlarged and sufficiently debrided. Calcium-hydroxide was applied for 2 weeks before the commencement of apexification and obturation, followed by esthetic rehabilitation. This case highlights the importance of recognizing rare anatomical variations in anterior teeth and demonstrates the invaluable role of CBCT in both diagnosing and managing such complexities.

Influence of periapical lesion volume on the radiodensity of surrounding bone: A CBCT study.

Aim: This study assesses if the size of periapical lesions has an effect on the bone immediately peripheral to an apical lesion. Methods: Cone-beam computed tomography (CBCT) images of 271 periapical lesions were analyzed using Mimics Research™ to determine the CBCT periapical lesion volume index (CBCTPAVI) score, along with the radiodensity of the lesion, lesion border, and surrounding bone in 0.5 mm increments up to 2.0 mm peripheral to the apical lesion. The one-way analysis of variance was used to assess for significant differences in the radiodensity of the lesion, border, and peripheral bone, as well as differences among CBCTPAVI scores. Results: The radiodensity of bone peripheral to the apical lesion increased significantly up to 1.0 mm around the lesion's perimeter. In addition, lesions with higher CBCTPAVI scores showed a significantly greater difference in the radiodensity from the lesion to the lesion border and the peripheral bone, compared to lesions with smaller CBCTPAVI scores. Conclusions: This study for the first time shows the influence of periapical lesion size on the radiodensity of bone peripheral to an apical lesion. Variations in radiodensity at the perimeter of a periapical lesion can be influenced by the size of the lesion, possibly indicating differences in defense response. Knowledge of these phenomena may provide information on bone healing and enhance our understanding of bone peripheral to a periapical lesion.