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Abstract Background The aim of this study was to evaluate the effect of thermal and mechanical cyclic aging using a mastication simulator on push-out bond strength of mandibular premolars obturated with AH Plus and BioRoot RCS root canal sealers. Methods With REVO-S files up to SU/0.06 taper, 48 single-rooted premolar teeth were instrumented. The teeth were randomly divided into two main groups (n = 24) based on the two root canal sealers used (AH Plus and BioRoot RCS). All teeth were obturated with h matched-taper single-cone. Each main group was then subdivided into three subgroups (A, B, and C) (n = 8). Group A served as the negative control group (no-thermocycling aging). While groups B and C were subjected to thermal changes in a thermocycler machine (15,000 and 30,000 thermal cycles, respectively), followed by two different dynamic loading periods, 3 × 105 and 6 × 105 in a masticatory simulator with a nominal load of 5 kg at 1.2 Hz which represent roughly 1½ and 3 years of clinical function respectively. 2 mm slice at 3 levels, apical, middle, and coronal, to obtain 3 sections were prepared and subjected to push-out test using a universal testing machine. Statistical analysis was performed using analysis of variance (ANOVA) followed by a Tukey post hoc comparisons test and an independent T-test. A significance level of 5% was used. Results After thermal–mechanical cyclic aging, the two root canal sealers showed a significantly decreased in push-out bond strength (p

A novel process design for the damage-free and highly accurate positional integration of an optical multi-axial force sensor into a hollow tube by means of rotary swaging is introduced. Numerical simulations reveal the relevant process phenomena of thin disc joining inside a pre-toothed hollow tube and help us to find an optimal process design. Experimental trials show the significant effect of the axial material flow and the number of tools on the rotary swaging process. By taking these effects into account, successful form- and force-fit joining of the sensor carrying discs into the tube can be achieved. Successful joining of an optical sensor for bending force and torque measurement shows hysteresis-free sensory behavior and thus backlash-free joining of the sensor carrier discs. The paper concludes with a presentation of the results of a numerical study on a potential closed-loop approach to the joining process.

Background: The most challenging part of diabetes management for a patient with diabetes is selecting a healthy diet. The purpose of this study is to evaluate participants’ knowledge of food labels, to find out the relationship between the type of diabetes mellitus (DM) and knowledge score of food labels, and to explore the barriers that prevent patients from reading food labels. Methodology: This observational study was conducted on patients with type 1 or type 2 diabetes using a validated self-administered questionnaire. The study was conducted at diabetes clinics at King Khalid University Hospital and King Abdul-Aziz University Hospital, Riyadh, Saudi Arabia, from November 2019 to February 2020. Data were analyzed using SPSS. Results: A total of 310 participants were enrolled in this study, of which 50.3% had type 1 DM, and more than half of them were female (51.6%). Patients with type 1 DM had higher mean declarative and applied knowledge scores than those with type 2 DM, regardless of whether they were taking pre meals insulin or not. The highest proportion (39.9%) had difficulty in understanding the content of the nutrition labels, and some of them (37.2%) did not receive any educational session about it. Only 9.5% of the participants did not have any difficulties in reading food labels. Conclusion: Patients with both types of diabetes tended to have poor total knowledge about food labels and faced difficulties in reading them. Provided educational sessions by primary health care and specialized physician and DM educator about food labels are recommended to help them to choose food properly.

Objectives The aim of the global DISCOVERing Treatment Reality of Type 2 Diabetes in Real World Settings (DISCOVER) Study was to provide a comprehensive real world assessment of the treatment pattern changes for patients with type 2 diabetes. The aim of this analysis was to assess the metabolic control and the annual incidence of hypoglycaemia, hospitalisation and complications among Saudi patients with type 2 diabetes initiating second-line therapy.Design This study is part of the observational, longitudinal, prospective multinational DISCOVER Study.Setting Governmental and private health sectors from different regions within Saudi Arabia.Participants The study recruited 519 patients with type 2 diabetes aged ≥18 years who were switching to second-line therapy. Patients who were already using insulin/injectable agents, patients with type 1 diabetes, pregnant women, and patients undergoing dialysis or with a history of renal transplantation were excluded.Primary and secondary outcome measures Metabolic control among patients with type 2 diabetes mellitus; fear of hypoglycaemia; quality of life; and the incidence of complications, hypoglycaemic events and/or hospitalisations. Data were analysed using descriptive statistics.Results A total of 519 patients were recruited with a mean age of 52.4±11 years. Of these participants, 54.7% were male and 45.3% were female. The incidence of hypoglycaemia was 56.72/1000 patient-years. The Hypoglycemia Fear Survey II showed a significant increase in patient worry related to hypoglycaemia from 6.4±11.9 at baseline to (p=0.0446) at the 36-month follow-up. The incidence of hospitalisation was 30.81/1000 patient-years. There was a moderate improvement in glycaemic control, represented as an HbA1c reduction from 8.8% at baseline to 8.2% at the 36-month follow-up. The incidence of macroangiopathy was 24.51/1000 patient-years and the incidence of microvascular complications such as retinopathy and albuminuria was 47.00/1000 patient-years and 221.71/1000 patient-years, respectively. The mean score of fear of hypoglycaemia showed an increase with 13.0±21.5 at baseline to 16.1±22.2 at the 36-month follow-up. When assessing the patients’ quality of life, there was an improvement in the mental component score from 47.4±9.1 at baseline to 53.0±6.7 at the 36-month follow-up.Conclusions Treatment intensification decisions should be made individually, weighing the benefit of good glycaemic control against the risk of hypoglycaemia.Trial registration number NCT02322762 and NCT02226822.

Abstract Buccal fat herniation is a rare traumatic disease that should be included in differential diagnosis of infants' oral cavity mass. History of proceeding trauma, careful evaluation of mucosal perforation aiding the diagnosis.

IntroductionThere is growing interest in Mindfulness-based Stress Reduction (MBSR) program to combat mental distress in medical students. In Saudi Arabia, literature is insufficient about MBSR and its effectiveness. This study aims to measure the effectiveness of MBSR in improving mindful state, stress, anxiety, and depression in medical students. Also, the study explores the association between the attendance rate of MBSR sessions and its effectiveness. Lastly, the study examines gender differences in response to MBSR.MethodsThis is a stratified randomized controlled study of 84 medical students from two medical schools in Riyadh, Saudi Arabia. They were recruited voluntarily from November 2018 to April 2021, and allocated to MBSR and waitlist groups using a stratified randomization method based on gender. MBSR group received eight weeks of sessions through audiovisual materials. An online survey utilizing validated questionnaires assessing stress, mindfulness, anxiety, and depression was used to evaluate both groups pre-program (time 0), post-program (time 1), and three months later (time 2).ResultsSeventy-one participants completed the post-test (time 1). There were no differences between study groups at time 0 and 1. However, in 41 subjects who completed the follow-up test (time 2), the anxiety dropped significantly in MBSR group (mean difference (MD), -3.935; 95% CI, -7.580 to -0.290). Furthermore, attending more MBSR sessions was inversely correlated with depression (r, -0.556; P, 0.002), and anxiety (r, -0.630; P, 0.000). Compared to their baseline, males in MBSR group improved in stress (MD, 3.08; 95% CI, 0.30 to 5.86), anxiety (MD, 4.91; 95% CI, 3.32 to 6.50), and mindfulness (MD, -0.58; 95% CI, -1.01 to -0.15), while females improved in stress (MD, 2.64; 95% CI, 0.02 to 5.26).ConclusionDespite the study being interrupted by the stressful COVID-19 outbreak, the findings suggest that MBSR improved psychological outcomes when participants commit to the program.

Abstract Background Carpal tunnel syndrome (CTS) is one of the most common nerve entrapments in the upper limb. In Saudi Arabia, few studies have investigated CTS in the general population. This study aimed to determine the association between personal factors and CTS. Methods A case-control study involved adults aged 18 and above. Cases were recruited from electrophysiology lab records as consecutive case series, while controls were individuals who were free of CTS symptoms according to the Boston Carpal Tunnel Questionnaire (BCTQ). The electronic medical records of participants were reviewed to obtain age, height, weight, medical conditions, and mobile numbers. Cases and controls were contacted via phone to complete a questionnaire that was designed based on previous literature. We used multivariate binary logistic regression to identify the personal factors significantly associated with CTS. Results A total of 95 cases and 190 controls were included. Most of the participants were female (84.2%) and Saudi (93%). Most of cases were above 45 years of age (73.7%), while 84.7% were 45 year – old or younger among the control group. Stratified logistic regression showed that performance of household chores was significantly associated with CTS. While physical exercise associated with decreased odds of CTS. Conclusions This study adds to the body of evidence on personal factors associated with CTS. However, the degree of differences in the age structure of the cases compared with the controls suggest that there is a considerable potential for residual confounding affecting the results. Trial registration number Not applicable.

Background: COVID-19 is newly emerging infectious disease that spread globally at unpredictable and unique pattern to the extent that the World Health Organization announced COVID-19 as a pandemic in the first couple months of 2020. This study aims to describe clinical and demographic features of COVID-19 patients and the influence of various risk factors on the severity of disease. Methods: This research is a retrospective study based on Saudi Arabia's ministry of health’s Covid-19 data. The analysis relies on data of all COVID-19 patients recorded in Riyadh between 1st, March 2020 and 30th, July 2020. Statistical analyses were performed to investigate the effect of demographic characteristic, clinical presentation, and comorbidities on infection severity. Results: A total number of 1026 COVID-19 patients were identified based on the demographic data as follows: 709 cases (69% of cases) were males and 559 cases (54% of cases) were Saudi. Most of patients were diagnosed with mild signs and symptoms 697 (68% of cases), while 164 patient (16% of cases) demonstrated moderate signs and symptoms, and 103 cases (10%) were severe and 62 (6%) had critical febrile illness. Fever, cough, sore throat, and shortness of breath were the most common symptoms among patients with COVID-19. Among studied comorbidities in COVID-19 patients, diabetes mellitus and hypertension were the most prevalent. The results from the bivariate logistic regression analysis revealed that older age, diabetes mellitus, asthma, smoking, and fever are associated with severe or critically ill cases. Conclusion: The findings of this study show that old age, fever, and comorbidities involving diabetes mellitus, asthma, and smoking were significantly associated with infection severity.

The aim of this study was to evaluate the aging effect of thermomechanical cyclic load on fracture resistance of lower premolars obturated with AH Plus and BioRoot RCS root canal sealers. Forty-eight single-rooted premolars teeth were instrumented with REVO-S files up to SU/0.06 taper. The teeth were randomly assigned into 2 main groups (n = 24) according to the selected two root canal sealers (AH Plus or BioRoot RCS). All teeth were obturated using matching gutta-percha. Each main group were further divided into 3 subgroups (A, B and C) (n = 8). Group A acted as the negative control group (non-Thermomechanical aging). Whereas Group B and C were subjected first to thermal variations in a thermal cycling machine (7500 and 15,000 thermal cycles), then two different dynamic loading periods namely 3 × 105 and 6 × 105 in a masticatory simulator with a nominal load of 5 kg at 1.2 Hz which simulate approximately 1 ½ and 3 years of clinical function respectively. The roots were decoronated and fracture resistance were measured using a universal testing machine. After thermal-mechanical aging, BioRoot RCS showed significantly higher fracture resistance (p < 0.05) than AH Plus. As the thermal-mechanical cycles increased both AH Plus and BioRoot RCS exhibited a significant decrease in fracture resistance (p < 0.05). It could be concluded that thermomechanical aging had a significant impact on the outcome of the fracture resistance of AH Plus and BioRoot RCS.

In this study, the relationship between a person’s walking speed and the perception threshold for discrete implicit repositioning during eyeblinks in a virtual environment is investigated. The aim is to estimate the perception thresholds for forward and backward repositioning during forward translation following eyeblink occurrences. A psychophysical method called Staircase Transformed and Weighted up/down is utilized to quantify the perception thresholds for forward and backward repositioning. The perception thresholds for this repositioning are estimated for three different walking speeds: slow (0.58 m/s), moderate (0.86 m/s), and fast (1.1 m/s). The collected observations are then analyzed using regression analysis. The estimated perception threshold values for imperceptible forward repositioning were 0.374, 0.635, and 0.897 meters for the abovementioned walking speeds, respectively. Moreover, the respective perception threshold values for imperceptible backward repositioning were 0.287, 0.430, and 0.572 meters for the same walking speeds. The findings reveal a proportional relationship between the perception threshold values and the participant’s walking speed. As such, it is possible to imperceptibly reposition a participant at a greater distance when they are walking faster relative to the same situation when the participant is walking slower. In addition, the results show that there is more tolerance in forward discrete repositioning compared to backward discrete repositioning during forward translation. These findings enable the extension of the manipulation types utilized by the Redirected Walking Technique. More specifically, this allows for implementing a sophisticated composite redirected walking controller, which utilizes continuous and discrete translation gains simultaneously; this helps not only with reducing the cognitive load, but also with reducing the amount of physical space required to support infinite free exploration in an immersive virtual environment.

Study designRetrospective cohort study of prospectively accrued data.ObjectiveTo evaluate a large, prospective, multicentre dataset of surgically treated degenerative cervical myelopathy (DCM) cases on the contemporary risk of C5 palsy with surgical approach.Summary of background dataThe influence of surgical technique on postoperative C5 palsy after decompression for DCM is intensely debated. Comprehensive, covariate-adjusted analyses are needed using contemporary data.MethodsPatients with moderate to severe DCM were prospectively enrolled in the multicenter, randomized, Phase III CSM-Protect clinical trial and underwent either anterior or posterior decompression between Jan 31, 2012 and May 16, 2017. The primary outcome was the incidence of postoperative C5 palsy, defined as the onset of muscle weakness by at least one grade in manual muscle test at the C5 myotome with slight or absent sensory disruption after cervical surgery. Two comparative cohorts were made based on the anterior or posterior surgical approach. Multivariate hierarchical mixed-effects logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI) for C5 palsy.ResultsA total of 283 patients were included, and 53.4% underwent posterior decompression. The total incidence of postoperative C5 palsy was 7.4% and was significantly higher in patients who underwent posterior decompression compared with anterior decompression (11.26% vs. 3.03%, P =0.008). After multivariable regression, the posterior approach was independently associated with greater than four times the likelihood of postoperative C5 palsy ( P =0.017). Rates of C5 palsy recovery were comparable between the two surgical approaches.ConclusionThe odds of postoperative C5 palsy are significantly higher after posterior decompression compared to anterior decompression for DCM. This may influence surgical decision-making when there is equipoise in deciding between anterior and posterior treatment options for DCM.Level of evidenceTherapeutic Level-II.

Objectives: The DISCOVER study is a global, prospective, three- year- observational (non-interventional) study that was conducted in 37 countries throughout the world including Saudi Arabia and aimed to assess variations in treatment patterns and therapeutic outcomes in type 2 diabetic patients. The current manuscript is reporting data of DISCOVER study across different health sectors of various provinces in the Kingdom of Saudi Arabia. Methods: In this study, 519 Saudi type 2 diabetics, non-insulin users, aged 18 years or older, initiating second line therapy, were selected from nine health institutes, in four out of five provinces in Saudi Arabia. Data was collected at baseline (initiation of 2nd line therapy) by the treating physician using an electronic case report form (eCRF) via a web-based data capture system. Each selected subject was asked to complete four self-administered questionnaires. Results: The mean age of the studied population was 52.4 ± 11 years. Among the subjects selected from the nine medical centers, 55% were men, with almost 65% between the ages of 46 and 65 years. The oral agent used as 1st line in the majority of patients was metformin, prescribed in 89.2% of the study cohort. In the second line, sitagliptin was the most frequently used, at 61.8%. followed by gliclazide, glibenclamide, and glimepiride at 35.6%, 13.1%, and 12.7%, respectively. Conclusion: Metformin, with or without sulfonylureas, is the most commonly prescribed first-line treatment for patients with type 2 diabetes, managed either in governmental institutions, or in the private sector. The most common second line drugs were DPP4 inhibitors, mainly sitagliptin, followed by the third and second generation of sulfonylureas. Drug affordability was not an issue, since the vast majority of the patients received medication free of charge. Keywords: Discover Type 2 diabetes, First line management, Second line management

In this study, we present a composite spatial manipulation framework for the redirected walking technique. The proposed framework focuses on utilizing two different approaches simultaneously to manipulate the user’s position and orientation in the physical space, aiming to substantially improve their redirection in a confined physical space and reduce the special requirements for the RDW technique. Each approach utilizes different perceptual processes. The first is a discrete spatial manipulation approach that introduces translation and/or rotation gains to the user’s virtual perspective in the immersive virtual environment (IVE) during temporal events such as eyeblinks. The second approach is the continuous spatial manipulation approach, which continuously introduces (with each frame) translation and/or rotation gains below the user’s perception threshold to their virtual perspective in the IVE. Two simulation experiments were conducted to investigate the feasibility of adopting the composite spatial manipulation framework for RDW without considering the user’s walking behavior or the impact of the proposed approach on user performance in the immersive virtual environment. In the second simulation experiment we aimed to investigate the performance of the proposed approach while considering the user’s walking behavior and performance in the IVE. Finally, a user experiment was conducted to validate the proposed framework and its impact on the user’s performance in the IVE. The findings revealed a significant improvement in the redirection performance of the proposed controller when it was compared to the classical RDW controller. Additionally, there was significant improvement in the user’s performance when the composite RDW controller was utilized.

Abstract Background The cost of depression among residents is staggering as it extends into the quality and safety of patient care. Finding an explanation to resident depression by investigating the associated factors is therefore important. Study skills can be a possible factor, and a clear gap in the literature exists in this regard. We sought to investigate the relationship between depressive symptoms among residents and their study skills. Methods This was a correlational study and a non-probability sample of 240 residents completed the Beck Depression Inventory II (BDI-II) and the Study Skills Inventory (SSI). Chi-square test was used to compare different categorical variables, while student t-test and ANOVA for continuous data. Pearson’s correlation coefficient was performed to find the relationship between depressive symptoms and study skills and the association that these measures have with the demographic variables. Results Overall, 186 residents (76%) filled out the questionnaire. The SSI total score was found to have a significant negative association with the BDI-II depression score (Pearson correlation = − 0.447and p

Background: To evaluate the knowledge and attitude level of recent dental graduates in Saudi Arabia toward stem cells and their potential therapeutic applications. Methods: In this cross-sectional study, a questionnaire was distributed among 606 recent graduates from 14 dental schools in Saudi Arabia. Fifteen statements were formulated to address the knowledge component with “yes” or “no” or “I do not know” answer and 10 statements were designed to assess the attitude level with Likert 5-point response scale. The level of knowledge for each respondent was designated as poor if the score value is (0–5), moderate (6–10), and high (11–15). To evaluate the attitude level for each respondent, a score of (1) was assigned for extremely negative answer and (5) for extremely positive answer for each statement. Based on the total score, attitude level was considered poor when the score value is (10–29), moderately positive (30–39), good (40–44), or excellent (45–50). Results: Significant difference was found in the knowledge score between males and females (p = 0.004). Both males and females showed poor knowledge with a mean score of 5.06 ± 2.5 and 5.63 ± 2.4, respectively. There was an overall moderately positive attitude of participants toward stem cells and their therapeutic applications with a mean value of 33.15 ± 5.92 with no significant difference between males and females (p = 0.53). A significant positive linear correlation was detected between knowledge and attitude for both males (r = 0.323, p = 0.00) and females (r = 0.392, p = 0.00). Conclusion: Updating dental curricula with topics on stem cell research and potential future applications in dentistry is demanded. Keywords: Stem cells, Knowledge, Attitude, Dental education, Recent graduates, Saudi Arabia

Objective: This study aimed to examine the effectiveness of oral health intervention on the improvement in knowledge and self-reported oral health behavior among 6–8 year old female primary school children in Riyadh, Saudi Arabia. Materials and methods: The sample consisted of 1661 girls in primary schools who are 6 to 8-year-olds (first, second and third graders). The children’s level of knowledge was assessed by a self-administered questionnaire that was formulated for this specific age and divided into two parts; oral health knowledge and self-reported oral health behavior. There were seven multiple choice questions and one true/false question with five underlying parts in the questionnaire which contained basic information about oral health knowledge, oral hygiene practices and certain habits that affect teeth. The questionnaires were distributed before and six weeks after implementation of the oral health educational program to measure the level improvement of knowledge regarding oral health among these children. Results: All the questions showed statistically significant improvement in knowledge and self-reported behavior in the post intervention group. There was a significant increase in the level of knowledge by 11.24% and level of self-reported behavior by 25% after intervention (P

Aim: This study aims to evaluate the retrieval outcome of the separated endodontic instrument by endodontic board residents. Materials and Methods: Records of 450 endodontic cases with separated endodontic instruments treated by endodontic Saudi board residents were randomly selected. The evaluation was based on the tooth type, type of fractured instrument, incidence and anatomical location in the root canal and if the instrument was retrieved, bypassed, or left. Data were statistically analyzed using IBM-SPSS.22. Results: A total of 84 (19%) separated instruments were identified. Thirty-four cases (7.55%) with separated instruments out of the total evaluated cases were done by residents. The incidence between hand stainless steel and nickel-titanium instruments was statistically significant (P < 0.05). The separated instruments were found more in the mandibular molars, i.e., 44 (52.4%). They were observed more in the buccal canal of the maxillary premolars and mesiobuccal canals of mandibular and maxillary molars. Fifty-seven (67.9%) of the separated fragments were located in the apical third of the root. Thirty-six (34.3%) were retrieved, 20 (19.0%) were bypassed, and 34 (32.4%) were left while 15 (14.3%) were managed by surgery. The ultrasonic device was more active in removing the separated instruments. Conclusions: Regardless of little experience of the endodontic residents, they were successfully managed to remove or bypass most of the separated instruments. Ultrasonic device was very helpful in removing the separated instrument.

Aim: To survey private dental clinics and analyze its clinicians in Riyadh city Saudi Arabia. Materials and methods: Private dental clinics that had been registered with the Ministry of Health (MOH), Health Affairs System and accepted to participate were included. All clinics were visited to collect data. Number of practicing dentists, nationality, and their specialty classification were recorded. The location and year of establishment of each dental center were also collected. Results: Out of 236 private dental clinics registered in MOH, 162 clinics accepted to participate. The total number of dentists in these clinics was 877. The majority of dentists were males (63.97%). The percentage of non-Saudi dentists were 86.66%, and Syrians dentists being the highest group (40.25%). The primary specialty of dentists was general dentistry (70.5%). The location of private dental clinics was found to be concentrated in some areas and not evenly distributed in Riyadh city. There were 49 clinics in Olaya, followed by 45 clinics in Rawdha municipality. Conclusion: Private dental clinics in Riyadh city are operated mainly by Non-Saudi dentists. Moreover, there is still a need for more female dentists and dental specialists. There are areas in Riyadh city that lack private dental clinics. Keywords: Dentists, Private dental centers, Workforce

Lockdowns due to the COVID-19 pandemic have forced universities to migrate entirely to eLearning to deliver classes. Students have found themselves using either synchronous, asynchronous, or mixed mode learning methods based on their universities' preferences. Many studies that investigated difficulties during the lockdown have been mainly concerned about technical difficulties. The reports lacked the investigation of differences among students' groups, with a few exceptions that highlighted differences among male and female students. Moreover, existing studies were found to focus on singular dimensions (TAM, IS success model, etc.). This study perceives that students, based on the various groups they belong to, can show different levels of perceptions towards determinants that influence the usage of eLearning. This study investigated differences among students in terms of determinants from TRI, TAM, and IS success model. A total of 915 participants from Malaysia and Saudi Arabia reported their perceptions. The findings reported in this study showed significant differences among participants, in particular, among groups of gender, age, country, and eLearning mode. It is noticeable that participants who used the asynchronous mode of eLearning gave more weight to information quality, system quality, service quality, perceived usefulness, perceived ease of use, innovation, optimism, satisfaction, and intention to use. Meanwhile, participants who used the synchronous mode experienced more discomfort. It could be said that the significant differences between the usage of synchronous and asynchronous modes should be considered for better quality of online learning.

In this paper we present a novel, cost-effective camera-based multi-axis force/torque sensor concept for integration into metallic load-bearing structures. A two-part pattern consisting of a directly incident and mirrored light beam is projected onto the imaging sensor surface. This allows the capturing of 3D displacements, occurring due to structure deformation under load in a single image. The displacement of defined features in size and position can be accurately analyzed and determined through digital image correlation (DIC). Validation on a prototype shows good accuracy of the measurement and a unique identification of all in- and out-of-plane displacement components under multiaxial load. Measurements show a maximum deviation related to the maximum measured values between 2.5% and 4.8% for uniaxial loads (Fx, Fy,Fz,Mz) and between 2.5% and 10.43% for combined bending, torsion and axial load. In the course of the investigations, the measurement inaccuracy was partly attributed to the joint used between the sensor parts and the structure as well as to eccentric load.

Objective: The purpose of this study was to investigate evolving trends in dental post graduate specialty preferences and career aspirations among final year dental students in Saudi Arabia. Materials and methods: A cross sectional survey using a self-administered questionnaire was conducted among final year dental students from seventeen universities in Saudi Arabia. The questionnaire enquired about socio-demographic details and the ranking of three of their best preferences among the list of specialties/general dentistry and career options. They were also enquired about their opinion regarding the total time required to become a dentist and their intention to go for further studies abroad. The questionnaire assessed factors influencing their choices using a 5 point Likert scale ranging from extremely important to not important. Binary logistic regression to examine the combined effect of several independent variables on the likelihood of choosing a dental specialization/general dentistry and career option were analyzed. Results: The overall response rate was 64.6%. Restorative and Aesthetic Dentistry was the most preferred specialty (n = 98; 17.7%) followed by Endodontics (n = 78; 14.1%); Prosthodontics (n = 65; 11.7%) and Orthodontics (n = 63; 11.4%). The two most preferred careers were ‘Civilian dentist in public sector’ followed by ‘Academic services dentist’. Overall, students reported that the influence of family members in the dental profession, preference for private practice and specific interest in patient population as the most important factors in choosing a specialty/general dentistry. Intellectual content of the specialty was ranked the least important. On the other hand, the most important factors for choosing a career were variety of non-clinical duties, access to child care facilities and research opportunities. Conclusion: The results of this study show the top preferred specialties and career choices which can be a baseline for establishing national policies and for the improvement of graduate programs. There seems to be a need to promote mentoring activities and provide guidance and encouragement to pre-doctoral dental students in selecting the most appropriate specialty within their capability domain. Keywords: Dental profession, Dental students, Dental career, Dental manpower, Dental specialties, Dental education

BACKGROUND:Medical students are faced with enormous academic demands that may influence their emotional wellbeing. The high rate of depression among medical students and its negative impact is an impetus to find explanation for the factors associated with it. Study skills that students possess might be such a factor. The current tools for the assessment of the study skills may have certain limitations, particularly for different cultural settings. OBJECTIVES:This study aimed to develop and validate a Study Skills Inventory (SSI), and to investigate the relationship between the students' study skills and the extent (severity) of depressive symptoms, measured using the validated tool. METHOD:The first version of the SSI was developed through expert consensus. The inventory was then administered to a randomly selected group of medical students. Confirmatory factor analysis was conducted for the internal validity. External validation was conducted by comparing the results of the SSI with the "Approaches and Study Skills Inventory for Students" (ASSIST). After validation, the correlation between the SSI total score with the Beck Depression Inventory II (BDI-II) total score was investigated using the Pearson correlation coefficient. The means of the total study skills scores for each severity category of depression were compared using ANOVA. RESULTS:A total of 23 items, representing five sub-scales, were included in the inventory. Based on 372 student responses (response rate of 93%), the five-factor solution explained a cumulative variance of 52% and Cronach alpha was 0.84. The SSI total score had a significant negative association with the BDI-II depression score (Pearson correlation of -.348** and P

The purpose of this ex vivo study was to evaluate the efficacy of three different irrigation techniques, ProRinse® syringe needle, ProUltra® PiezoFlow TM , and EndoActivator®, in cleaning the canals and isthmuses of human mandibular molars using a software program ImageJ. Materials and Methods : A custom-made metal cube was used to create a sealed canal system. Eighty extracted mandibular molars were randomly divided into four equal groups. Teeth were mounted; sectioned at 2, 4, and 6 mm; and reassembled into the metal cube. Chemo-mechanical preparation was done for all teeth. The teeth were divided into four groups for final debridement: Group 1 (control group) received only needle irrigation, group 2 used the ProRinse® syringe needle with 5% NaOCl irrigation within a 1-mm working length, group 3 used ProUltra® PiezoFlow TM ultrasonic agitation for 30 seconds, and group 4 used the EndoActivator® system to agitate for 30 seconds. All groups received a final irrigation with 5% NaOCl in each canal. Specimens were evaluated by digital image capture with a stereomicroscope. Statistical analysis was completed using an ANOVA test and Tukey′s test. Results: The results showed no statistically significant difference in canal or isthmus cleanliness between the four groups. However, there was a statistically significant difference (P < 0.05) in isthmus cleanliness in group 4 at the 4-mm level. Conclusions: EndoActivator® produced a good result in isthmus cleaning at the 4-mm level.

Aim: The aim of this study was to compare the calcium hydroxide (Ca(OH) 2 ) removal efficacy of the EndoActivator system with that of conventional irrigation with a syringe and hand file manipulation. Materials and Methods: A total of 44 extracted human single-rooted mandibular premolars were used. The root canal systems of all teeth were cleaned and shaped, then filled with Ca(OH) 2 paste. The teeth were divided into two groups: Ca(OH) 2 was removed using ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) with hand filing and irrigation (Group 1) or the EndoActivator system (Group 2). Each tooth was split into two halves and examined under a scanning electron microscope. Results: Ca(OH) 2 particles were completely removed at the coronal level in both experimental groups. More Ca(OH) 2 particles were present in the apical third than in the middle-third in both groups. No significant interaction was observed between the two experimental groups or among the three examined levels (P > 0.05). Conclusion: Agitation with NaOCl and EDTA improved Ca(OH) 2 removal only in the coronal third of the root canal. Use of the EndoActivator system did not improve the efficacy of Ca(OH) 2 removal in the middle and apical thirds.

Background and Aim: This study was conducted to assess the periodontal knowledge, orientations of Saudi medical interns and the medical curriculum. Study Population and Methodology: Questionnaires were distributed to 221 medical interns chosen randomly from two major educational institutions in Saudi Arabia. Questions were developed from literature reviews. The questionnaire had five true/false knowledge items, and eight Likert-scale questions. Data were analyzed by computerized SPSS (version 20). Level of significance was set at P < 0.05. Results: Of the 221 respondents, 66% were male and 34% were female. Most of the participants were 24 years old (48%). About 40% of the interns answered all five true/false general knowledge questions correctly, nearly half of the respondents (49.8%) reported they never asked patients if they were diagnosed with periodontal disease, 93.2% reported not receiving any training about periodontal disease in medical school, 23.5% reported they would feel absolutely uncomfortable performing a simple periodontal examination, about one-third of interns (29.4%) agreed that patients expect physicians to discuss/screen for periodontal disease, 43.9% felt that discussing/evaluating the periodontal status of their patients was peripheral to their role as physicians, nearly half of interns (48.4%) reported never screening patients for periodontal disease, and 33% stated they never referred patients to dentists. Conclusion: Medical interns were not prepared nor trained to screen patients for periodontal disease. They had limited knowledge about the association between periodontal health and general health. Oral health training as part of the medical curriculum is strongly recommended.

The aim of the study is to develop a real-time eyeblink detection algorithm that can detect eyeblinks during the closing phase for a virtual reality headset (VR headset) and accordingly classify the eye’s current state (open or closed). The proposed method utilises analysis of a motion vector for detecting eyelid closure, and a Haar cascade classifier (HCC) for localising the eye in the captured frame. When the downward motion vector (DMV) is detected, a cross-correlation between the current region of interest (eye in the current frame) and a template image for an open eye is used for verifying eyelid closure. A finite state machine is used for decision making regarding eyeblink occurrence and tracking the eye state in a real-time video stream. The main contributions of this study are, first, the ability of the proposed algorithm to detect eyeblinks during the closing or the pause phases before the occurrence of the reopening phase of the eyeblink. Second, realising the proposed approach by implementing a valid real-time eyeblink detection sensor for a VR headset based on a real case scenario. The sensor is used in the ongoing study that we are conducting. The performance of the proposed method was 83.9% for accuracy, 91.8% for precision and 90.40% for the recall. The processing time for each frame took approximately 11 milliseconds. Additionally, we present a new dataset for non-frontal eye monitoring configuration for eyeblink tracking inside a VR headset. The data annotations are also included, such that the dataset can be used for method validation and performance evaluation in future studies.

Feed spacers in reverse osmosis systems generate complex fluid flows that limit computational fluid dynamics (CFD) simulations to small length and time scales. That limits our ability to simulate mineral scaling and other membrane fouling phenomena, which occur over longer length and time scales. Thus motivated, we develop a reduced model that replaces the CFD simulation of the velocity field with an analytical model that mimics spacers. This focuses the remaining numerical effort on simulating the advection–diffusion equation governing solute transport. We motivate and validate the model with CFD simulations and bench-scale experiments of spacer filaments in three different arrangements, including cases of unsteady vortex shedding. We show that the model produces a roughly 10,000-fold speedup compared to CFD, and accurately reproduces CFD predictions of not only the average and maximum concentrations, but also the local concentration distribution along the membrane. We also demonstrate the model for simulating a feed channel with a length-to-height ratio of 200. The model provides a simple testbed for exploratory studies of multispecies transport, precipitation, and membrane fouling phenomena for which simulating spacers is often prohibitive.

Objectives. The aim of this cross-sectional study was to identify sleeping patterns among dental students and their association with self-reported bruxism in Riyadh Colleges of Dentistry and Pharmacy (RCsDP). Methods. A cross-sectional study was performed including 549 students (67 men and 482 women). A structured questionnaire was adopted from The PSQI (The Pittsburgh Sleep Questionnaire Index) used for data collection. It included questions which are categorized into sleeping habits, sleep-related symptoms, and additional questions concerning bruxism. This questionnaire was randomly distributed among all college preclinical and postclinical students. Sleep bruxism diagnosis was based on self-reported data. The data were analyzed using Chi-square tests through SPSS software for Windows. Results. Statistical analyses revealed significant correlations between self-reported bruxism and sleeping habits including sleep initiation (χ2=22.6, p=0.000), continuous sleep until morning (χ2=19.2, p=0.001), nighttime sleep duration (χ2=20.2, p=0.000), and length of daytime naps (χ2=28.35, p=0.000). There was an association between self-reported bruxism and sleeping-related symptoms including awakening early in the morning before the usual time without a cause (χ2=16.52, p=0.000) and increased nightmares (χ2=13.7, p=0.001). Conclusions. Poor sleeping pattern was an important factor among dental students, who reported sleep bruxism.

Aim: To determine the prevalence of the number of root canals in permanent maxillary first and second premolars of a Saudi Arabian sub-population. Results will be compared to previous Asian studies. Materials and Methods: A total of 894 periapical radiographs of endodontically treated maxillary first and second premolars of 628 Saudi patients (268 males and 360 females) were viewed. The teeth were segregated into maxillary first premolars (463) and maxillary second premolars (431). The diagnostic, working length, master cone and final films with different angles were mounted, projected and, with the utilization of written clinical records, evaluated. Teeth with multiple canal systems were categorized according to whether the canals exited the root by common or separate apical foramen. Data was analyzed statistically using Chi-square test and professional t-test, by comparing pairs of groups with the significant level established at 5% (P < 0.05). Results: More than 90% of first maxillary premolar and more than 50% of the second maxillary premolar was found to have two canals. There was no significant difference between male (92%) and female (95%) in the distribution of the two root canals of the first maxillary premolar (t-test = 1.21, P value = 0.228), however, there was significant difference between the distributions of male (69.4%) and female (52.2%) of the two root canals within the second maxillary premolar (t-test = 3.75, P value = 0.000). Few teeth showed three canals. Conclusion: The number of root canals of the maxillary first premolar in Saudi population shows a higher incidence of two canals (93.6%) than previously reported. In addition, the figure is higher than most of the Asian countries.