Fatigue resistance of new and used nickel-titanium rotary instruments: a comparative study

Aim of the present study was twofold. First, to evaluate in vitro, the performance of two different NiTi rotary instruments in one molar case; then, to evaluate their resistance to cyclic fatigue, compared to new ones

Exploring Multivariate Profiles of Psychological Distress and Empathy in Early Adolescent Victims, Bullies, and Bystanders Involved in Cyberbullying Episodes

(1) Background: Adolescents may be involved in cyberbullying as victims, perpetrators, or to a lesser extent, victim–perpetrators simultaneously. The present research investigated differences between participants acting in different bullying roles—namely, bully, victim, or bully/victim—and bystander roles—namely, defending, passive bystander, and passive/defending; (2) Methods: We used multivariate analysis of covariance to determine how, in the same individuals, direct involvement in cyberbullying episodes compares to participating in them as by-standers in relation to both psychological distress and empathy; (3) Results: Both victims and bully/victims were found to be at increased risk for suicidal ideation, internalizing and externalizing symptoms, and emotional dysregulation compared with students who were neither victims nor perpetrators of cyberbullying episodes. Additionally, victims showed higher empathy scores when compared with bullies and bully/victims. All bystander roles showed increased emotional dysregulation compared with uninvolved students, but no differences emerged on other psychological distress measures. Finally, defending bystanders showed increased cognitive empathy. (4) Conclusions: During early adolescence, the direct experience of cyberbullying, as a bully or a victim (or both), show a stronger association with psychological distress than the mere participation in cyberbullying as a witness, regardless of the witness acting defensive toward the victim, or passive. However, both cyberbullying and bystanding roles provide a similar (small) explicative power over empathy variables

Efforts for the Correct Comprehension of Deceitful and Ironic Communicative Intentions in Schizophrenia: A Functional Magnetic Resonance Imaging Study on the Role of the Left Middle Temporal Gyrus

Deficits in social cognition and more specifically in communication have an important impact on the real-life functioning of people with schizophrenia (SZ). In particular, patients have severe problems in communicative-pragmatics, for example, in correctly inferring the speaker’s communicative intention in everyday conversational interactions. This limit is associated with morphological and functional alteration of the left middle temporal gyrus (L-MTG), a cerebral area involved in various communicative processes, in particular in the distinction of ironic communicative intention from sincere and deceitful ones. We performed an fMRI study on 20 patients with SZ and 20 matched healthy controls (HCs) while performing a pragmatic task testing the comprehension of sincere, deceitful, and ironic communicative intentions. We considered the L-MTG as the region of interest. SZ patients showed difficulties in the correct comprehension of all types of communicative intentions and, when correctly answering to the task, they exhibited a higher activation of the L-MTG, as compared to HC, under all experimental conditions. This greater involvement of the L-MTG in the group of patients could depend on different factors, such as the increasing inferential effort required in correctly understanding the speaker’s communicative intentions, and the higher integrative semantic processes involved in sentence processing. Future studies with a larger sample size and functional connectivity analysis are needed to study deeper the specific role of the L-MTG in pragmatic processes in SZ, also in relation to other brain areas

Analysis of stability in time of marginal adaptation of endosequence root repair material on biological samples

Introduction: The introduction of mineral trioxide aggregate (MTA) and bioceramic sealers increased the success rate of endodontic surgery and perforation repair. The aim of this study was to evaluate the marginal adaptation at different times of endosequence root repair material (ERMM) in order to evaluate its dimensional stability using variable pressure-scanning electron microscope (VP-SEM). Material and Methods: Fourty-eight teeth were selected shaped up to a master apical size of 25. Then a 3mm cut perpendicular to the long axis and a retrograde cavity preparation were performed. In order to obtain 2mm thick sample a second cut was done and, in this disk, ERMM was inserted. The samples were stored at 37°.The samples were divided into four time-depending groups observed with VP-SE Mat time0 (Group 1) andafter2 (Group2),7(Group 3) and 30 days (Group4) after ERRM setting. Statistical analysis with one way-ANOVA test was performed (95%). Results: None of the four groups analyzed showed a complete marginal adaptation between dentin and ERRM. Instead, in all groups ERRM exhibited a completely preserved marginal adaptation to the dentin wall in all time-dependent groups. The mean (±SD) gap value was fortime0,3.91(±2.55) mmafter2days,4.32(±2.69), after7days4.49(±2.53), and after30days4.81(±2.85) mm. No statistically significant difference was found between the four groups. Conclusions: The results of the present study demonstrate the dimensional stability over time of ERMM

Digital design of minimally invasive endodontic access cavity

New minimally invasive endodontic cavities have been described and proposed to preserve dentin (and enamel) through strategic access, including point endodontic access cavity (PEAC). There is no consensus to what extent PEAC contributes to tooth's resistance to fracture, because there is no agreement on how PEAC should be performed. The purpose of the present study is to describe and classify four different types of PEACs and to examine if a dynamic navigation system /DNS) could allow planning and precisely executing these cavities in vitro. Forty TrueTooth TM Replica # 3-001 models, were randomly divided into four identical groups of ten and scanned using a cone bean computed tomography (OP-Maxio 300, Instrumentarium-Kavo, Finland). Then, four different access cavities were planned and performed by using DNS (Navident dynamic navigation system, ClaroNav, Toronto, ON, Canada). For each tooth, a different PEAC was designed to obtain endodontic access to the main mesio-buccal canal (MB1), resulting in a different location of the entry point on the occlusal surface of the tooth. Precision was evaluated by comparing deviation in the inclinations between the planned and real cavity. Data were recorded and statistically analyzed. DNS allowed preparation of minimally invasive "straight line" cavities, with some differences in the accuracy

NASA's Robotic Lunar Lander Development Program

NASA Marshall Space Flight Center and the Johns Hopkins University Applied Physics Laboratory have developed several mission concepts to place scientific and exploration payloads ranging from 10 kg to more than 200 kg on the surface of the moon. The mission concepts all use a small versatile lander that is capable of precision landing. The results to date of the lunar lander development risk reduction activities including high pressure propulsion system testing, structure and mechanism development and testing, and long cycle time battery testing will be addressed. The most visible elements of the risk reduction program are two fully autonomous lander flight test vehicles. The first utilized a high pressure cold gas system (Cold Gas Test Article) with limited flight durations while the subsequent test vehicle, known as the Warm Gas Test Article, utilizes hydrogen peroxide propellant resulting in significantly longer flight times and the ability to more fully exercise flight sensors and algorithms. The development of the Warm Gas Test Article is a system demonstration and was designed with similarity to an actual lunar lander including energy absorbing landing legs, pulsing thrusters, and flight-like software implementation. A set of outdoor flight tests to demonstrate the initial objectives of the WGTA program was completed in Nov. 2011, and will be discussed

Effect of a laser-ablated micron-scale modification of dental implant collar surface on changes in the vertical and fractal dimensions of peri-implant trabecular bone

Background. Marginal bone loss (MBL) represents an important indicator of peri-implant health and the measure of its level is considered a determining factor in the evaluation of the quality of survival. Aim of this study is to compare radiographic changes in the fractal and mesial/distal vertical dimensions of peri-implant trabecular bone of dental implants with a laser-ablated micron-scale modication (LAM) of collar surface after a 5-year follow-up period. Materials and methods. Thirty-four implants with LAM of collar surface (test group = TG) and 31 implants without LAM of collar surface (control group = CG) were placed in 45 non-smoking, periodontally healthy patients. Fractal and vertical dimensions of peri-implant trabecular bone were measured by comparing radiographs taken immediately after prosthesis delivery with those taken 3 years and 5 years after functional loading. Results. At the end of the 5-year follow-up, the MBL in the TG was 0.87±0.21 and 0.75±0.25 mm at the mesial and distal aspects, respectively, while a MBL of 2.05±0.25 mm at the mesial aspect and 2.01±0.34 mm at the distal site was recorded in the CG. A statistically significant difference was noted. In the TG the mean fractal dimension before loading was 1.4213±0.0525. It increased significantly to 1.4329±0.0479 at 3 years after loading and remained almost stable at 5 years after loading (1.4327±0.0291). In the CG the mean fractal dimension before loading was 1.4119±0.0414. It increased significantly to 1.4282±0.0324 at 3 years after loading and decreased significantly to 1.4111±0.0624 at 5 years after loading. At the end of the follow-up, differences between both study groups were statistically significant. Conclusions. The increased fractal dimension and the reduced MBL around TG implants after 5 years of functional loading indicates a positive effect of a laser-ablated micron-scale modication of collar surface on peri-implant trabecular bone remodeling

Mental Health and Treatment Considerations for Urban Populations

Addressing mental health problems in urban populations represent an important challenge for the theoretical and clinical approach to treatment. This chapter presents a general framework for better understanding mental health in urban environments. We highlight the emerging evidence for the relations between risks and protective factors and urban mental health. We focus on current global issues for preventing and reducing mental illness in urban populations and aim to offer practical suggestions for clinical applications