The Accuracy of Intraoral Registration for Dynamic Surgical Navigation in the Edentulous Maxilla.

PURPOSE: Despite the high clinical accuracy of dynamic navigation, inherent sources of error exist. The purpose of this study was to improve the accuracy of dynamic-navigated surgical procedures in the edentulous maxilla by identifying the optimal configuration of intraoral points that results in the lowest possible registration error for direct clinical implementation. MATERIALS AND METHODS: Six different four-area configurations (left and right sides; n = 12) were tested by three operators against two negative controls (left and right sides) and one positive control (three-area and eight-area configurations, respectively) using a skull model. The two dynamic navigation systems (X-Guide and Navident) and the two registration methods (bone surface tracing and fiducial markers) produced four registration groups: XG tracing, ND tracing, XG fiducial, and ND fiducial. The accuracy of the registration was checked at the frontal process of the zygoma. Intra- and interoperator reliabilities were reported for each registration group. Multiple comparisons were conducted to find the best configuration with the minimum registration error. RESULTS: Ranking revealed one configuration in the tracing groups (Conf.3) and two configurations in the fiducial groups (Conf.3 and Conf.5) that had the best accuracy. When the inferior surfaces of the zygomatic buttress were excluded, fiducial registration produced better accuracy with both systems (P = .006 and < .0001). However, bilaterally tracing 1-cm areas at these surfaces resulted in similar registration accuracy to placing fiducial markers there (P = .430 and .237). Navident performed generally better (P = .049, .001, and .002), but the values had a wider margin of uncertainty. Changing the distribution of the four tracing areas or fiducial markers had a less pronounced effect with the X-Guide than with the Navident system. CONCLUSIONS: For surgery in the edentulous maxilla, four fiducial markers placed according to Conf.3 or Conf.5 resulted in the lowest registration error. Where implants are being placed bilaterally, an additional two sites may further reduce the error. For bilateral zygomatic implant placement, it is optimal to place two fiducial markers on the inferior surfaces of the maxillary tuberosities, two on their buccal surfaces, and another two on the anterior labial surface of the alveolar bone. Utilizing the inferior zygomatic buttress is recommended over the inferior maxillary tuberosities in other types of maxillary surgeries.

Improvement in facial aesthetics of orthognathic patients after surgery-first approach.

Facial appearance significantly affects psychosocial wellbeing, and an improvement in facial aesthetics is considered an essential outcome of orthognathic treatment. The surgery-first approach (SFA) has emerged as a promising alternative to the conventional orthodontics-first approach (OFA) due to its potential advantages in reducing treatment duration and cost, delivering early aesthetic improvement, and increasing patient satisfaction. However, its impact on final facial aesthetics and how it compares with the OFA has, to our knowledge, not yet been investigated. This retrospective study aimed to compare the improvement in facial aesthetics after orthognathic surgery in an SFA and an OFA group. Preoperative and postoperative 3-dimensional stereophotogrammetry facial images of 40 patients were evaluated by five professional assessors using the Global Aesthetic Improvement Scale (GAIS). Similar aesthetic improvement outcomes were found in both the SFA and OFA groups. The GAIS score significantly correlated with the following facial variables: upper lip projection, chin prominence, facial proportions, paranasal hollowing, lip competence, mandibular projection, and facial profile. No significant correlation was found between a change in aesthetic score and the surgical variables. There was a positive association between overall GAIS score and the gender and experience level of the individual assessors. This study suggests that aesthetic facial improvement achieved with the SFA is satisfactory and comparable to that of the OFA.

Rapid Identification of Aphid Species by Headspace GC-MS and Discriminant Analysis.

Aphids are a ubiquitous group of pests in agriculture that cause serious losses. For sustainable aphid identification, it is necessary to develop a precise and fast aphid identification tool. A new simple chemotaxonomy approach to rapidly identify aphids was implemented. The method was calibrated in comparison to the established phylogenetic analysis. For chemotaxonomic analysis, aphids were crushed, their headspace compounds were collected through closed-loop stripping (CLS) and analysed using gas chromatography-mass spectrometry (GC-MS). GC-MS data were then subjected to a discriminant analysis using CAP12.exe software, which identified key biomarkers that distinguish aphid species. A dichotomous key taking into account the presence and absence of a set of species-specific biomarkers was derived from the discriminant analysis which enabled rapid and reliable identification of aphid species. As the method overcomes the limits of morphological identification, it works with aphids at all life stages and in both genders. Thus, our method enables entomologists to assign aphids to growth stages and identify the life history of the investigated aphids, i.e., the food plant(s) they fed on. Our experiments clearly showed that the method could be used as a software to automatically identify aphids.

Comparison of Composite Resin (Duo-Shade) Shade Guide with Vita Ceramic Shades Before and After Chemical and Autoclave Sterilization.

BACKGROUND This study aimed to compare a composite resin (Duo-Shade) shade guide with Vita ceramic shades before/after chemical and autoclave sterilization. MATERIAL AND METHODS Color values (L*a*b*) were recorded directly from shade tabs of prefabricated composite resin (Brilliant NG Universal Duo-Shade) and ceramic (Vita classic) shade guide with a calibrated spectrophotometer (Vita Easy Shade Advance 4.0). Seventy-two composite resin disk samples with 6 different shades (A1/B1, A2/B2, A3/D3, A3.5/B3, A4/C4, and C2/C3) (n=12 each) were divided into 2 groups (Gp) - Gp A (Autoclave) and Gp C (Chemical) (15 cycles) - to assess their influence on respective shades. Mean values calculated the color differences (ΔE) while differences in color values (L*a*b*) were graded on the National Bureau of Standards (NBS) 6-grade scale and assessed for Clinical Acceptance/Perceptible Threshold (CAT), (CPT). All differences were considered significant if the color difference ΔE was ≥3.3. RESULTS Only 2 out of 12 Shade tabs (C2C3, A4C4) of composite resin matched to Vita shade tab C2 and C4 (ΔE ≤3.3). Both groups showed notable color differences after respective sterilization protocols, with color differences in Gp A significantly higher than Gp C (DE ³3.3). Within groups, all shades in Gp A showed remarkably different color changes, with shade C2C3 and A1B1 being denoted as clinically unacceptable. CONCLUSIONS Manufacturer-provided shade guides do not match ceramic shades as claimed and chemical sterilization using 10% Deconex was associated with less color changes than with autoclave sterilization.

GC Analysis, Anticancer, and Antibacterial Activities of Secondary Bioactive Compounds from Endosymbiotic Bacteria of Pomegranate Aphid and Its Predator and Protector.

Bacterial secondary metabolites are a valuable source of various molecules that have antibacterial and anticancer activity. In this study, ten endosymbiotic bacteria of aphids, aphid predators and ants were isolated. Bacterial strains were identified according to the 16S rRNA gene. Ethyl acetate fractions of methanol extract (EA-ME) were prepared from each isolated bacterium and tested for their antibacterial activities using the disk diffusion method. The EA-ME of three bacterial species, Planococcus sp., Klebsiella aerogenes, Enterococcus avium, from the pomegranate aphids Aphis punicae, Chrysoperia carnea, and Tapinoma magnum, respectively, exhibited elevated antibacterial activity against one or several of the five pathogenic bacteria tested. The inhibition zones ranged from 10.00 ± 0.13 to 20.00 ± 1.11 mm, with minimum inhibitory concentration (MIC) values ranging from 0.156 mg/mL to 1.25 mg/mL. The most notable antibacterial activity was found in the EA-ME of K. aerogenes against Klebsiella pneumonia and Escherichia coli, with an MIC value of 0.156 mg/mL. The cytotoxic activity of EA-ME was dependent on the cell line tested. The most significant cytotoxicity effect was observed for extracts of K. aerogenes and E. avium, at 12.5 µg/mL, against the epithelial cells of lung carcinoma (A549), with a cell reduction of 79.4% and 67.2%, respectively. For the EA-ME of K. aerogenes and Pantoea agglomerans at 12.5 µg/mL, 69.4% and 67.8% cell reduction were observed against human colon cancer (Hct116), respectively. Gas chromatography-mass spectrometry (GC-MS) analysis of three EA-ME revealed the presence of several bioactive secondary metabolites that have been reported previously to possess antibacterial and anticancer properties. To the best of our knowledge, this is the first study to examine the biological activities of endosymbiotic bacteria in aphids, aphid predators and ants. The promising data presented in this study may pave the way for alternative drugs to overcome the continued emergence of multidrug-resistant bacteria, and find alternative drugs to conventional cancer therapies.

The effect of COVID-19 vaccination on the menstrual cycle in female in Riyadh, Saudi Arabia.

Background: Recently, few studies have mentioned minor changes in women's menstrual cycle after the COVID-19 vaccination. There were many reported cases of female menstrual cycle problems in primary healthcare clinics in Riyadh, Saudi Arabia. The study aimed to explore the prevalence of menstrual irregularities after the COVID-19 vaccine among females of childbearing age in Riyadh, Saudi Arabia. Materials and Methods: This observational cross-sectional study was conducted from dec 2021 to June 2022 in Saudi Arabia. The study was carried out by using a convenience sampling technique. Results: Our analysis includes 1066 participants. Abnormal menstruation was significantly associated with hypertension (p-value = 0.024), polycystic ovary syndrome (p-value = 0.001), and at least one gynaecological condition (p-value < 0.001). However, the multivariate regression analysis showed that menstrual abnormality before receiving the COVID-19 vaccine (OR = 0.09, 95% CI, 0.06 to 0.14, p-value < 0.001) was more likely to be associated with abnormal menstruation after receiving the vaccine. Conclusions: Our study findings showed a significant association between covid-19 vaccination and menstruation irregularity before administering the covid-19 vaccine, irrespective of vaccine type or the number of doses administered. Future and ongoing clinical trials should investigate menstrual abnormalities, other abnormal vaginal bleeding and hormonal changes post-vaccination, especially the COVID-19 vaccine.

The phylogenetic relationship among two species of genus Nebo (Scorpiones: Diplocentridae) from Saudi Arabia and Middle East.

BACKGROUND: The genus Nebo has been identified as a medically important scorpion species distributed across Arabia and the Middle East. However, its taxonomic status remains unclear. AIM: The molecular phylogeny of two Nebo species from Saudi Arabia and comparative sequences from Palestine is presented based on the mitochondrial cytochrome oxidase subunit I (COI) gene. METHODOLOGY: Scorpion specimens were collected from two different localities, mainly the Southern part of Saudi Arabia. Then, DNA was extracted, amplified using invertebrate universal primers, and sequenced to identify the COI gene. The obtained sequences were analyzed, and phylogenetic trees based on maximum parsimony, neighbor-joining, and Bayesian inference were constructed. RESULTS: The inferred phylogeny indicates the monophyletic status of the family Diplocentridae and its subfamily Nebinae and Diplocentrinae. Also, the phylogenetic analyses support the existence of interspecific and intraspecific variations among/ within Nebo hierichonticus and Nebo yemenensis which may indicate distinct species. CONCLUSION: Further morphological studies with additional specimens from the Arabian Peninsula may reveal possible undiscovered and cryptic species.

The Association Between Hair Loss and COVID-19: The Impact of Hair Loss After COVID-19 Infection on the Quality of Life Among Residents in Saudi Arabia.

Background Coronavirus disease 2019 (COVID-19) is an infectious disease that is associated with many health conditions, including, but not limited to, dermatological diseases. Some patients suffer from hair loss after becoming infected with severe acute respiratory syndrome coronavirus 2. Acute telogen effluvium (TE) is a non-scarring hair loss that usually occurs three months after a stressful event and can last up to six months, and it can be associated with post-COVID-19 infections. This study aims to explore the prevalence of hair loss among recovered COVID-19 patients in Saudi Arabia and determine the contributing factors. Furthermore, we aimed to measure the impact of hair loss after COVID-19 on their quality of life. Methodology An observational, cross-sectional study was conducted from September to December 2021 in Saudi Arabia. A questionnaire was used to assess hair loss after being infected with COVID-19. Furthermore, quality of life was assessed using the Dermatology Life Quality Index (DLQI) questionnaire. Participants were recruited by sharing the questionnaire on social media platforms (Twitter, Telegram, and WhatsApp). The data were analyzed using SPSS version 23 (IBM Corp., Armonk, NY, USA). Frequency and percentages were used to display categorical variables, while minimum, maximum, mean, and standard deviation were used to present continuous variables. The categorical variables were compared using a chi-square test, and the statistical significance cut-off was set at p < 0.05. Results A total of 806 participants were included in the study, of whom 52.7% experienced hair loss after COVID-19 infection. Age, gender, high temperature during, and the presence of hair loss prior to infection were significantly associated with the incidence of TE. The severity of life affection based on DLQI showed that 91.4% of the participants did not have severe life affection, while 8.6% had their lives severely affected. Conclusions This study revealed subjective hair loss that was significantly associated with high temperature, being female, and having a history of previous hair loss. Further studies using objective assessments are suggested for reaching more precise conclusions.

Molecular Identification of Newly Recorded Louse Columbicola tschulyschman Eichler (Phthiraptera: Philopteridae) From Saudi Arabia With a Note on Genus Columbicola spp. Phylogeny.

Chewing lice comprise a large group of ectoparasites that colonize and adversely affect several domestic and wild birds including pigeons. In Saudi Arabia, there is a lack of studies describing such ectoparasites and their infestation rates. Through this work, a new record, Columbicola, tschulyschman Eichler (C. tschulyschman Eichler) was collected from domestic pigeons (Columba livia domestica, Linnaeus). The collected C. tschulyschman Eichler was morphologically identified based on specific taxonomic keys. Mitochondrial (COI) and nuclear (EF-1α) gene fragments were used for molecular identification and phylogenetic reconstruction. In this study, the C. tschulyschman Eichler accounted for around 69.40%. To our knowledge, this is the first report of C. tschulyschman Eichler in Riyadh, Saudi Arabia. To improve the tree topology and differentiate between genera, further studies should utilize the 16s rRNA.

Pattern of pterygomaxillary disarticulation associated with Le Fort I maxillary osteotomy.

Pterygomaxillary disarticulation (PMD) contributes to surgical complications of Le Fort 1 osteotomy and is associated with undesirable fractures of the pterygoid plates. The aim of this paper was to investigate the patterns of PMD in Le Fort I osteotomies using Rowe's disimpaction forceps, and to evaluate correlations with age and anatomical measurements. Cone-beam computed tomography (CBCT) scans of 70 consecutive orthognathic patients were retrospectively evaluated to study four patterns of PMD: Type 1 - PMD at, or anterior to, the pterygomaxillary junction (PMJ); Type 2 - PMD posterior to the PMJ; Type 3 - PMJ separation with comminuted fracture of the pterygoid plates; Type 4 - disarticulation of the maxilla involving the pterygoid plates above the level of the osteotomy line. The preoperative anteroposterior and mediolateral thicknesses of the PMJ and the length of the medial and lateral pterygoid plates were assessed. Satisfactory PMD was achieved in all cases and no severe complications were reported, including vascular, dental, mucosal, or neural damage. The most common PMD was Type 1 (54.3%), followed by Type 2 (40%). Comminuted fracture of the pterygoid plates was limited to 5.7% of cases, and no Type 4 was detected. A weak correlation was detected between PMJ thickness and PMD pattern (p = 0.04). No statistically significant correlation was detected between patients' age and type of PMD. PMD of Le Fort I maxillary osteotomy using a Smith spreader and Rowe's disimpaction forceps proved safe, with minimal damage to the pterygoid plates.

Physicians' Knowledge, Practices, and Perceptions of Reporting Communicable Diseases at Primary Health Care Centers in Jeddah, Saudi Arabia: A Cross-Sectional Study.

Background Jeddah has the highest international traffic and is among the most diverse cities in Saudi Arabia. The chance of importing an emerging communicable disease is significant, particularly during the religious seasons. Therefore, timely and accurate reporting of communicable diseases at primary health care centers (PHCCs) is crucial. Objectives The main objective of this study was to assess physicians' knowledge, practices, and perceptions of reporting communicable diseases at PHCCs in Jeddah, Saudi Arabia. Methods The study was a cross-sectional study comprising 143 physicians from all PHCCs in Jeddah from October 2017 to February 2018. An electronic questionnaire was used to collect data to assess the physicians' knowledge, practices, and perceptions related to reporting communicable diseases at PHCCs. Results A total of 106 physicians participated in the study. Although only 21.7% of the physicians had received training on reporting communicable diseases, the average knowledge score for the six commonly reported diseases was 72%. More than half (58.5%) of the physicians indicated that they had reported at least one disease. However, there was no agreement on who should be responsible for reporting communicable diseases at PHCCs. Furthermore, some obstacles were perceived that could prevent disease reporting, including physicians not knowing which diseases to report (66%), not knowing how or whom to report to (54.7%), and a limited diagnostic or laboratory capacity (52.8%). Conclusions Reporting communicable diseases at PHCCs was of adequate quality. However, some obstacles must be addressed, and regular applied training must be provided. More extensive assessments are needed to improve the reporting of communicable diseases locally and nationally.

Classification of Autism Spectrum Disorder From EEG-Based Functional Brain Connectivity Analysis.

Autism is a psychiatric condition that is typically diagnosed with behavioral assessment methods. Recent years have seen a rise in the number of children with autism. Since this could have serious health and socioeconomic consequences, it is imperative to investigate how to develop strategies for an early diagnosis that might pave the way to an adequate intervention. In this study, the phase-based functional brain connectivity derived from electroencephalogram (EEG) in a machine learning framework was used to classify the children with autism and typical children in an experimentally obtained data set of 12 autism spectrum disorder (ASD) and 12 typical children. Specifically, the functional brain connectivity networks have quantitatively been characterized by graph-theoretic parameters computed from three proposed approaches based on a standard phase-locking value, which were used as the features in a machine learning environment. Our study was successfully classified between two groups with approximately 95.8% accuracy, 100% sensitivity, and 92% specificity through the trial-averaged phase-locking value (PLV) approach and cubic support vector machine (SVM). This work has also shown that significant changes in functional brain connectivity in ASD children have been revealed at theta band using the aggregated graph-theoretic features. Therefore, the findings from this study offer insight into the potential use of functional brain connectivity as a tool for classifying ASD children.

A novel surgical model for the preclinical assessment of the osseointegration of dental implants: a surgical protocol and pilot study results.

BACKGROUND: Dental implants are considered the gold standard replacement for missing natural teeth. The successful clinical performance of dental implants is due to their ability to osseointegrate with the surrounding bone. Most dental implants are manufactured from Titanium and it alloys. Titanium does however have some shortcomings so alternative materials are frequently being investigated. Effective preclinical studies are essential to transfer the innovations from the benchtop to the patients. Many preclinical studies are carried out in the extra-oral bones of small animal models to assess the osseointegration of the newly developed materials. This does not simulate the oral environment where the dental implants are subjected to several factors that influence osseointegration; therefore, they can have limited clinical value. AIM: This study aimed to develop an appropriate in-vivo model for dental implant research that mimic the clinical setting. The study evaluated the applicability of the new model and investigated the impact of the surgical procedure on animal welfare. MATERIALS AND METHODS: The model was developed in male New Zealand white rabbits. The implants were inserted in the extraction sockets of the secondary incisors in the maxilla. The model allows a split-mouth comparative analysis. The implants' osseointegration was assessed clinically, radiographically using micro-computed tomography (µ-CT), and histologically. A randomised, controlled split-mouth design was conducted in 6 rabbits. A total of twelve implants were inserted. In each rabbit, two implants; one experimental implant on one side, and one control implant on the other side were applied. Screw-shaped implants were used with a length of 8 mm and a diameter of 2 mm. RESULTS: All the rabbits tolerated the surgical procedure well. The osseointegration was confirmed clinically, histologically and radiographically. Quantitative assessment of bone volume and mineral density was measured in the peri-implant bone tissues. The findings suggest that the new preclinical model is excellent, facilitating a comprehensive evaluation of osseointegration of dental implants in translational research pertaining to the human application. CONCLUSION: The presented model proved to be safe, reproducible and required basic surgical skills to perform.

Molecular identification of Campanulotes bidentatus Scopoli, 1763 (Phthiraptera, Philopteridae) infecting the domestic pigeon Columba livia from Saudi Arabia.

The taxonomy of the order Phthiraptera is unstable and still problematic to researchers. Most of the current taxon classifications are mainly based on morphological features. Campanulotes bidentatus belongs to the chewing lice of the Philopteridae family that mostly parasitic on birds. There is a lack of sequence data and phylogenetic analyses on the family Philopteridae. In the current study, C. bidentatus was collected from the domestic pigeon Columba livia and identified morphologically and molecularly based on the mitochondrial cytochrome c oxidase subunit 1 gene (COI). The infection rate of the Campanulotes genus was approximately 58.82% in this study. Phylogenetic analysis based on the mt COI gene was informative for members of Philopteridae and the group taxon genera formed distinct clades. Future studies were recommended using the 16s rRNA to enhance the tree topology and obtain clear differentiation between genera.

Prevalence and risk factors of myasthenia gravis recurrence post-thymectomy.

OBJECTIVES: To evaluate the prevalence and the factors associated with recurrence of myasthenia gravis following thymectomy. METHODS: Six electronic databases which reported on recurrence of myasthenia gravis following thymectomy and/or its risk factors from 1985 to 2018 were searched. Summary prevalence and risk values obtained based on the random effect models were reported. RESULTS: Seventy (70) papers containing 7,287 individuals with myasthenia gravis who received thymectomy as part of their management were retrieved. The patients had a mean follow-up of 4.65 years post-thymectomy. The prevalence of myasthenia gravis recurrence post-thymectomy was 18.0% (95% CI 14.7-22.0%; 1865/7287). Evident heterogeneity was observed (I2=93.6%; p<0.001). Recurrence rate was insignificantly higher in male compared with female patients (31.3 vs. 23.8%; p=0.104). Pooled recurrence rates for thymomatous (33.3%) was higher than the rate among non-thymomatous (20.8%) myasthenia gravis patients (Q=4.19, p=0.041). Risk factors for recurrence include older age, male sex, disease severity, having thymomatous myasthenia gravis, longer duration of the myasthenia gravis before surgery, and having an ectopic thymic tissue. CONCLUSION: A fifth of individuals with myasthenia gravis experience recurrence after thymectomy. Closer monitoring should be given to at-risk patients and further studies are needed to understand interventions to address these risks.

Cognitive Outcome Prediction in Infants With Neonatal Hypoxic-Ischemic Encephalopathy Based on Functional Connectivity and Complexity of the Electroencephalography Signal.

Impaired neurodevelopmental outcome, in particular cognitive impairment, after neonatal hypoxic-ischemic encephalopathy is a major concern for parents, clinicians, and society. This study aims to investigate the potential benefits of using advanced quantitative electroencephalography analysis (qEEG) for early prediction of cognitive outcomes, assessed here at 2 years of age. EEG data were recorded within the first week after birth from a cohort of twenty infants with neonatal hypoxic-ischemic encephalopathy (HIE). A proposed regression framework was based on two different sets of features, namely graph-theoretical features derived from the weighted phase-lag index (WPLI) and entropies metrics represented by sample entropy (SampEn), permutation entropy (PEn), and spectral entropy (SpEn). Both sets of features were calculated within the noise-assisted multivariate empirical mode decomposition (NA-MEMD) domain. Correlation analysis showed a significant association in the delta band between the proposed features, graph attributes (radius, transitivity, global efficiency, and characteristic path length) and entropy features (Pen and SpEn) from the neonatal EEG data and the cognitive development at age two years. These features were used to train and test the tree ensemble (boosted and bagged) regression models. The highest prediction performance was reached to 14.27 root mean square error (RMSE), 12.07 mean absolute error (MAE), and 0.45 R-squared using the entropy features with a boosted tree regression model. Thus, the results demonstrate that the proposed qEEG features show the state of brain function at an early stage; hence, they could serve as predictive biomarkers of later cognitive impairment, which could facilitate identifying those who might benefit from early targeted intervention.

Difficulties in conducting clinical research among healthcare practitioners in Saudi Arabia: A cross-sectional survey.

BACKGROUND: Research activity represents an important process conducted to address an issue in a precise and systematic manner. Data of this kind regarding the methodological difficulties encountered by healthcare practitioners in conducting clinical research in Saudi Arabia are scarce. This study aims to assess the methodological difficulties encountered by healthcare practitioners in conducting clinical research in Saudi Arabia. MATERIALS AND METHODS: This cross-sectional survey was conducted among healthcare practitioners who conducted or who were involved in research in Saudi Arabia from June 2018 through August 2018. Data were collected through SurveyMonkey, using a modified version of a questionnaire from a previous similar study. RESULTS: Overall, 236 respondents participated in the study, more than half, that is, 131 (55.50%) had conducted research as principal investigators, 41 (17.40%) had never attended a research workshop, and 57 (24.20%) were members of research committees. Respondents identified "formulating the research title" and "cooperation between research partners" as the easiest research steps by 58 (24.58%) for each. "Receiving funds and financial resources to complete the research project" ranked the highest difficult step by 124 (52.54%) of the respondents. Attending >2 clinical research workshops was significantly associated with lower methodological difficulty scores. Specifically, those who attended scored 35.28 ± 12.86, while those who did not scored 42.34 ± 12.64, with a highly statistically significant difference (P = 0.001). CONCLUSION: These findings show that securing funding and finding an available biostatistician contributed greatly to the methodological difficulties of conducting clinical research. The difficulty score decreased significantly with increasing the number of clinical research workshops attended by the researchers.

Characterization of the 12S rRNA Gene Sequences of the Harvester Termite Anacanthotermes ochraceus (Blattodea: Hodotermitidae) and Its Role as A Bioindicator of Heavy Metal Accumulation Risks in Saudi Arabia.

Termites are social insects of economic importance that have a worldwide distribution. Identifying termite species has traditionally relied on morphometric characters. Recently, several mitochondrial genes have been used as genetic markers to determine the correlation between different species. Heavy metal accumulation causes serious health problems in humans and animals. Being involved in the food chain, insects are used as bioindicators of heavy metals. In the present study, 100 termite individuals of Anacanthotermes ochraceus were collected from two Saudi Arabian localities with different geoclimatic conditions (Riyadh and Taif). These individuals were subjected to morphological identification followed by molecular analysis using mitochondrial 12S rRNA gene sequence, thus confirming the morphological identification of A. ochraceus. Furthermore, a phylogenetic analysis was conducted to determine the genetic relationship between the acquired species and other termite species with sequences previously submitted in the GenBank database. Several heavy metals including Ca, Al, Mg, Zn, Fe, Cu, Mn, Ba, Cr, Co, Be, Ni, V, Pb, Cd, and Mo were measured in both collected termites and soil samples from both study sites. All examined samples (termite and soil) showed high concentrations of metals with different concentrations and ratios. Generally, most measured metals had a significantly high concentration in soil and termites at Taif, except for Ca, Cd, Co, Cr, Cu, Mg, and Ni showing significantly high concentrations at Riyadh. Furthermore, termites accumulated higher amounts of heavy metals than the soil at both locations. The mean concentrations of the measured metals in soil samples were found to be in the descending order Ca ˃ Al ˃ Mg ˃ Zn ˃ Fe ˃ Cu ˃ Mn ˃ Ba ˃ Cr ˃ Co ˃ Be ˃ Ni ˃ V ˃ Pb ˃ Cd ˃ Mo, while it was Ca ˃ Mg ˃ Al ˃ Fe ˃ Zn ˃ Cu ˃ Mn ˃ Be ˃ Ba ˃ Pb ˃ Cr ˃ V ˃ Ni ˃ Cd ˃ Mo ˃ Co in termite specimens. The mean concentrations of the studied metals were determined in the soil and termite specimens at both locations. In addition, the contamination factor, pollution load index (PLI) and degree of contamination were calculated for all studied metals in different samples, indicating that both studied sites were polluted. However, Taif showed a significantly higher degree of pollution. Thus, the accurate identification of economically important insects, such as termites, is of crucial importance to plan for appropriate control strategies. In addition, termites are a good bioindicator to study land pollution.

Diagnostic challenges of an unusually large schwannoma of the mandible: Report of a case.

Schwannomas are slow-growing, benign neoplasms arising from the Schwann cells and are commonly reported as peripheral tumors in the head and neck region. Central intramandibular schwannomas are extremely rare lesions. We report a case of intramandibular schwannoma in a 70 year old male patient. Panoramic radiography revealed a large, multilocular radiolucent lesion with distinct borders involving the right mandibular body and ramus. A complete excision was achieved by removing the tumor followed by reconstruction of the mandible. The clinical, radiological, and histopathological features are discussed within the context of this case.

Failure rate of inferior alveolar nerve block among dental students and interns.

OBJECTIVES: To report the failure rate of inferior alveolar nerve block (IANB) among dental students and interns, causes of failure, investigate awareness of different IANB techniques, and to report IANB-associated complications.   METHODS: A 3-page questionnaire containing 13 questions was distributed to a random sample of 350 third to fifth years students and interns at the College of Dentistry, King Saud University, Riyadh, Saudi Arabia on January 2011. It included demographic questions (age, gender, and academic level) and questions on IANB failure frequency and reasons, actions taken to overcome the failure, and awareness of different anesthetic techniques, supplementary techniques, and complications.   RESULTS: Of the 250 distributed questionnaires, 238 were returned (68% response rate). Most (85.7%) of surveyed sample had experienced IANB failure once or twice. The participants attributed the failures most commonly (66.45%) to anatomical variations. The most common alternative technique used was intraligamentary injection (57.1%), although 42.8% of the sample never attempted any alternatives. Large portion of the samples stated that they either lacked both knowledge of and training for other techniques (44.9%), or that they had knowledge of them but not enough training to perform them (45.8%).  CONCLUSION: To  decrease IANB failure rates for dental students and interns, knowledge of landmarks, anatomical variation and their training in alternatives to IANB, such as the Gow-Gates and Akinosi techniques, both theoretically and clinically in the dental curriculum should be enhanced.