Evaluation of orthognathic surgery on articular disc position and temporomandibular joint symptoms in skeletal class II patients : a magnetic resonance imaging study

The purpose of orthognathic surgery is to correct facial deformity and dental malocclusion and to obtain normal orofacial function. However, there are controversies of whether orthognathic surgery might have any negative influence on temporomandibular (TM) joint. The purpose of this study was to evaluate the influence of orthognathic surgery on articular disc position and temporomandibular joint symptoms of skeletal CI II patients by means of magnetic resonance imaging. For this purpose, fifteen patients with skeletal CI II malocclusion, aged 19-32 years (mean 23 years), 10 women and 5 men, from the Isfahan Department of Oral and Maxillofacial Surgery were studied. All received LeFort I and bilateral sagittal split osteotomy (BSSO) osteotomies and all patients received pre- and post-surgical orthodontic treatment. Magnetic resonance imaging was performed 1 day preoperatively and 3 month postoperatively. Descriptive statistics and Wilcoxon and Mc-Nemar tests were used for statistical analysis. P<0.05 was considered significant. Disc position ranged between 4.25 and 8.09 prior to surgery (mean=5.74±1.21). After surgery disc position range was 4.36 to 7.40 (mean=5.65±1.06). Statistical analysis proved that although TM disc tended to move anteriorly after BSSO surgery, this difference was not statistically significant (p value<0.05). The findings of the present study revealed that orthognathic surgery does not alter the disc and condyle relationship. Therefore, it has minimal effects on intact and functional TM joint

Effects of Sucrose, Skim Milk and Yeast Powder on Survival of Lactobacillus rhamnosus GG Encapsulated with Alginate during One-week Storage at room Conditions

Background and Objective: During the manufacture and storage of probiotic products, there are always possibilities that probiotics be exposed to harmful stresses such as high temperature, low pH, various osmotic pressures and high oxygen levels, which can decrease the number of living cells. Encapsulation is one of the methods used to protect living cells such as probiotic bacteria from environmental challenges. Up-to-date, various compounds with abilities to protect bacteria during freeze-drying and to increase viability during storage have been identified. In this study, alginate with&nbsp;calcium chloride was used&nbsp;to&nbsp;encapsulate&nbsp;probiotic&nbsp;bacteria using extrusion method. Then, effects of sucrose and skim milk as cryoprotectants and yeast powder containing beta-glucan as prebiotic on the survival of these bacteria were investigated. Material and Methods: The Homogeneous solution of bacteria with alginate and cry protectants were manually extruded into a calcium chloride solution. After 30 min of agitation, shaped beads were separated. For the comparison, bacterial population were enumerated in the primary culture, after encapsulation, freeze-drying and 1 week of storage at room conditions (N0, N, NF and N1w, respectively). To assess colony-forming unit per ml of the samples, first 1 g of fresh beads was dissolved in 9 ml of trisodium citrate and then serial dilution and pour plate techniques were carried out. Plates were incubated for 24-48 h and colonies were counted. Results and Conclusion: Results showed that encapsulation of bacteria with alginate and calcium chloride alone was 51% effective while use of yeast powder and sucrose with alginate increased the encapsulation efficiency to 97 and 99%, respectively. Furthermore, use of skim milk with alginate and sucrose resulted in the highest survival rate after 1 week of storage at room conditions. Therefore, encapsulation of probiotic bacteria with alginate layer and yeast powder containing prebiotics, sucrose and skim milk can be effective in survival of these bacteria. Conflict of interest: The authors declare no conflict of interest

COVID-19 and Dentistry

From MDPI via Jisc Publications RouterHistory: accepted 2021-06-17, pub-electronic 2021-06-21Publication status: PublishedDentistry is a healthcare profession requiring close contacts between the dental practitioner and the patient. In particular, many dental procedures generate aerosols and droplets which are proved to be the major transmission route for COVID-19

Application of Fractal Analysis in Detecting Trabecular Bone Changes in Periapical Radiograph of Patients with Periodontitis

Evaluation of detailed features of the supporting bone is an important step in diagnosis and treatment planning for teeth with clinical attachment loss. Fractal analysis can be used as a method for evaluating the complexity of trabecular bone structures. The aim of this study was to evaluate the trabecular bone changes in periapical radiographs of patients with different stages of periodontitis using fractal analysis. Methods. This comparative cross-sectional study was performed on patients with and without clinical attachment loss in mandibular first molars. Teeth with clinical attachment loss were divided into mild, moderate, and severe periodontitis groups. Digital periapical radiographs were obtained from the mandibular first molars using the same exposure parameters. DICOM file of the radiographs was exported to ImageJ software for fractal analysis. Three regions of interest (ROIs) were considered in each radiograph: two proximal ROIs mesial and distal to the mandibular first molar and one apical ROI. Fractal dimension (FD) values were calculated using the fractal box counting approach. Statistical analysis was performed using the chi-square test, Mann–Whitney test, intraclass correlation coefficient, and ANOVA (α = 0.05). Results. FD values were significantly different between moderate and severe periodontitis and healthy periodontal bone (P0.05). Conclusion. Fractal analysis is a useful tool for evaluation of bone alterations in moderate and severe periodontitis, but was not able to detect the most initial radiographic bone signs of mild periodontitis

Magnetic-property enhancement of sized controlled cobalt-gold core-shell nanocrystals

Cobalt nanoparticles and cobalt-gold core-shell nanoparticles were synthesized via reverse-micelle microemulsion method with emphasis on size control. Cobalt nanoparticles become easily oxidized therefore coating a gold shell on cobalt nanoparticles was necessary and can effectively reduce the oxidation of Co while maintaining most of its magnetic properties. Controlling the size of nanoparticles was performed by adjusting the water to surfactant ratio of reverse micelle solution during synthesis. X-ray diffraction data was used to calculate the crystallinity percentage and percentage of phases presented in Co-Au core-shell nanoparticles. The results from transmission electron microscopy, and field emission electron microscopy combined to energy dispersive x-ray spectroscopy provide direct evidence for shell growth. The average coating layer (shell thickness) in all cases observed to be 4-5 nm. Magnetic properties of samples were investigated using a vibrating sample magnetometer before and after annealing. Magnetic properties enhanced after annealing in all cases. An increase in saturation magnetization after annealing was due to increase in cystallinity percentage. A simple method was applied to measure a totally intrinsic blocking temperature in zero field cooled-warmed (ZFC-W) curves without employing an external magnetic field. The B-field dependence temperature data of Co-Au nanoparticles before and after annealing showed an intrinsic blocking temperature of 45 and 40 K respectively

Artificial intelligence in detecting mandibular fractures: A review of literature

Background: Mandibular fractures are a common trauma in oral and maxillofacial surgery. The accurate diagnosis of these fractures is crucial for successful treatment. However, the interpretation of radiographic scans can be time-consuming and prone to human error. The advent of artificial intelligence (AI), specifically Convolutional Neural Networks (CNNs), has opened up new possibilities for improving the accuracy and efficiency of fracture detection.Objectives: This review aims to explore the role of AI in detecting mandibular fractures.Methods: A comprehensive literature search was performed using PubMed, Embase, Web of Science, and Google Scholar databases. Studies were included if they used AI techniques, specifically CNNs or transformers, for the detection of mandibular fractures.Results: The systematic search yielded 53 studies, with eight studies meeting the inclusion criteria. The AI models across these studies demonstrated a generally high degree of effectiveness in detecting mandibular fractures, with F1 scores ranging from 45% to 100%. Some studies also compared the diagnostic prowess of human clinicians and AI models, with AI models often matching or surpassing human performance.Conclusion: The application of AI in detecting mandibular fractures represents a promising avenue of research. AI models have the potential to reduce the workload of radiologists, improve the efficiency of fracture detection, and lead to faster diagnosis and treatment. However, further research is needed to validate these findings in larger and more diverse datasets and to address challenges such as the interpretability of AI algorithms and the availability of large, well-annotated datasets

Comparison of the Effects of Articaine and Lidocaine Anesthetics on Blood Pressure after Maxillary Infiltration Technique: A Triple-Blind Randomized Clinical Trial

Background. Many dental procedures begin with local anesthesia. Subsequent increase in blood pressure in healthy individuals commonly occurs and may be affected by several factors such as mental and physical stress, painful stimuli, and action of catecholamines present in local anesthetic solutions.êim of the present study is to compare the effects of 4% articaine with 1 :100000 epinephrine and 2% lidocaine with 1 : 80000 epinephrine on blood pressure after maxillary infiltration technique. Materials and Methods. In this randomized clinical trial, 102 patients were randomly assigned into two groups. One group received 4% articaine with 1 :100000 epinephrine and the other group received 2% lidocaine with 1 : 80000 epinephrine for local maxillary infiltration. Systolic and diastolic blood pressure of both groups was determined twice: once before anesthetic injection and once 10 minutes after injection.%e data were statistically analyzed using descriptive statistics, Shapiro–Wilks test, Levene test, chi-square test, independent t-test, and paired t-test. Results. %e mean systolic blood pressure after anesthetic injection in the articaine and lidocaine groups was 125.00 ± 5.67 and 123.16 ± 6.417 mmHg, respectively, showing no statistically significant difference (p � 0.127). %e mean diastolic blood pressure after injection was 85.02 ± 7.331 in the articaine group and 81.35 ± 12.815mmHg in the lidocaine group. %ese values show no statistically significant difference (p � 0.080). In both groups, the mean systolic and diastolic blood pressures have increased significantly (p < 0.001). Conclusion. Articaine can be regarded as a suitable alternative for lidocaine for maxillary local infiltration, as no significant difference was observed between the effects of the two anesthetic solutions on blood pressure

Analysis of COVID-19 articles published in dental journals

Introduction: Coronavirus disease 2019 (COVID-19) pandemic is an ongoing global health crisis with unmatched outcomes and effects. This pandemic has caused an infodemic of article publication in scientific journal. Dental journals have been active in publication of COVID-19 related articles from the beginning of the pandemic. In this report, we present an analysis of the scientific output of dental journals on COVID-19.Methods: Special COVID-19 database of PubMed was searched on December 3, 2020 with applying Dental Journals filter. Data including article type, journal name, country, and number of PubMed citations were recorded.Results: The search retrieved a total of 658 articles, of which 26 were excluded as a result of duplicate records, the article being in a language other than English, the article being a correction or unrelated or briefing of other articles. 632 articles were included in the analysis. Oral Diseases has published the most COVID-19 articles (13.9%), followed by British Journal of Oral and Maxillofacial Surgery (8.1%), Journal of Dental Education (7.6%), British Dental Journal (6.8%) and Journal of Craniofacial Surgery (5.5%). Most of the articles were from researchers from the United States (168), United Kingdom (120), Brazil (83), Italy (64), China (54), and India (35). Most of the published articles were original articles (22.3%), letters (20.7%), reviews (15.3%), commentaries/perspectives/opinions (13.4%) and editorials (8.9%). The number of citations of the published articles ranged from 0 to 406. Most articles (64.2%) did not have any citations and only 5.0% of them had 10 or more citations.Conclusion: The dental community has been active in publication of COVID-19 articles from the beginning of the pandemic. The papers published by dental journals explore issues such as management of clinical practices during the outbreak, infection control in the dental setting, signs and symptoms of COVID-19 affecting the oral cavity, and the impact of COVID-19 pandemic on educational and clinical programs

Designing and Fabricating Nano-Structured and Micro-Structured Radiation Shields for Protection against CBCT Exposure

Researchers have always been interested in finding new and effective materials for protection against radiation. This experimental study aimed to design and fabricate new types of nano-material and micro-material based shields against the ionizing effect of cone beam computed tomography (CBCT) X-rays. To fabricate a flexible prototype, we added dioctyl phthalate (DOP) oil to emulsion polyvinyl chloride (PVC) powder. The paste was mixed and dispersed. Then, nano-and micro-powders of WO3 and Bi2O3 were added to the paste, with the weight ratio of 20% PVC, 20% DOP, and 60% nano-and micro-metals. Using an ultrasonic mixer, the polymer matrix and metals were mixed and a paste with a thick texture was developed. The resultant paste was poured into glass molds and the molds were then heated in an oven. After cooling, the resultant sheets were selected for further experiments. A CBCT unit and dosimeter were used to evaluate the characterization and X-ray shielding properties of the fabricated prototypes. The half-value layers (HVL) for nano-WO3, micro-WO3, nano-Bi2O3, and micro-Bi2O3 were 0.0390, 0.0524, 0.0351, and 0.0374 cm, respectively. In addition, the linear attenuation coefficient (µ) for these materials were 17.77, 13.20, 19.71, and 18.5 cm−1, respectively. The findings indicate that nano-structured samples are more effective in the attenuation of X-ray energy. The nano-structured WO3 prototype was nearly 34% more efficient in attenuating radiation compared to the micro-structured WO3 prototype. This difference in nano-and micro-structured Bi2O3 prototypes was 6.5