Effectiveness of a new non-hydrogen peroxide bleaching agent after single use - a double-blind placebo-controlled short-term study

Tooth whitening represents perhaps the most common aesthetic procedure in dentistry worldwide. The efficacy of bleaching depends on three aspects: bleaching agent, bleaching method, and tooth color. Objective: This in vivo study aimed to examine whitening effects on frontal teeth of the upper and lower jaws using an over-the-counter (OTC) non-hydrogen peroxide bleaching agent in comparison to a placebo after one single use. Material and methods: Forty subjects (25 female; 15 male) participated in this double-blind randomized placebo-controlled trial. The subjects were randomly allocated to two groups (n=20). The test group received the OTC product (iWhite Instant) and the placebo group received an identically composed product except for the active agents. Each subject was treated with a prefilled tray containing iWhite Instant or the placebo for 20 minutes. The tooth shade of the front teeth (upper and lower jaws) was assessed before (E_0), immediately after (E_1) and 24 h after treatment (E_2), using a shade guide (VITA classical). Statistical testing was accomplished using the Mann-Whitney U test (

Genome-wide trans-ancestry meta-analysis provides insight into the genetic architecture of type 2 diabetes susceptibility.

To further understanding of the genetic basis of type 2 diabetes (T2D) susceptibility, we aggregated published meta-analyses of genome-wide association studies (GWAS), including 26,488 cases and 83,964 controls of European, east Asian, south Asian and Mexican and Mexican American ancestry. We observed a significant excess in the directional consistency of T2D risk alleles across ancestry groups, even at SNPs demonstrating only weak evidence of association. By following up the strongest signals of association from the trans-ethnic meta-analysis in an additional 21,491 cases and 55,647 controls of European ancestry, we identified seven new T2D susceptibility loci. Furthermore, we observed considerable improvements in the fine-mapping resolution of common variant association signals at several T2D susceptibility loci. These observations highlight the benefits of trans-ethnic GWAS for the discovery and characterization of complex trait loci and emphasize an exciting opportunity to extend insight into the genetic architecture and pathogenesis of human diseases across populations of diverse ancestry

Large-scale association analysis provides insights into the genetic architecture and pathophysiology of type 2 diabetes

To extend understanding of the genetic architecture and molecular basis of type 2 diabetes (T2D), we conducted a meta-analysis of genetic variants on the Metabochip involving 34,840 cases and 114,981 controls, overwhelmingly of European descent. We identified ten previously unreported T2D susceptibility loci, including two demonstrating sex-differentiated association. Genome-wide analyses of these data are consistent with a long tail of further common variant loci explaining much of the variation in susceptibility to T2D. Exploration of the enlarged set of susceptibility loci implicates several processes, including CREBBP-related transcription, adipocytokine signalling and cell cycle regulation, in diabetes pathogenesis

How does Identity Theory contribute to the Continuance Use of E-learning: The mediating role of Inertia and moderating role of computer Self-efficacy

Despite e-learning’s rapid growth and significant benefits, especially during the COVID-19 pandemic, retaining students in this educational environment is a critical challenge in the post-corona era. Therefore, our research was conducted to explore how we can promote the continuance use of e-learning (CUEL) platforms. More specifically, this study examines how identity, inertia, and computer self-efficacy affect CUEL. Data were collected from 384 users and provided support for the model. The results indicated that social identity, relational identity, and inertia are critical determinants of CUEL. Furthermore, inertia mediates the relation between social identity and CUEL. In addition, we found that computer self-efficacy moderates the relation of inertia and relational identity with CUEL, but its moderating effect on the influence of social identity and CUEL is not supported. Finally, the theoretical and practical implications of this study are discussed.</p

Effectiveness of a new non-hydrogen peroxide bleaching agent after single use - a double-blind placebo-controlled short-term study

Abstract Tooth whitening represents perhaps the most common aesthetic procedure in dentistry worldwide. The efficacy of bleaching depends on three aspects: bleaching agent, bleaching method, and tooth color. Objective: This in vivo study aimed to examine whitening effects on frontal teeth of the upper and lower jaws using an over-the-counter (OTC) non-hydrogen peroxide bleaching agent in comparison to a placebo after one single use. Material and methods: Forty subjects (25 female; 15 male) participated in this double-blind randomized placebo-controlled trial. The subjects were randomly allocated to two groups (n=20). The test group received the OTC product (iWhite Instant) and the placebo group received an identically composed product except for the active agents. Each subject was treated with a prefilled tray containing iWhite Instant or the placebo for 20 minutes. The tooth shade of the front teeth (upper and lower jaws) was assessed before (E_0), immediately after (E_1) and 24 h after treatment (E_2), using a shade guide (VITA classical). Statistical testing was accomplished using the Mann-Whitney U test (p<0.001). The dropout rate was 0%. Results: There were no significant differences at E_0 between placebo and test groups regarding the tooth color. Differences in tooth color changes immediately after (ΔE1_0) and 24 h after treatment (ΔE2_0) were calculated for both groups. The mean values (standard deviations) of tooth color changes for ΔE1_0 were 2.26 (0.92) in the test group and 0.01 (0.21) in the placebo group. The color changes for ΔE2_0 showed mean values of 2.15 (1.10) in the test group and 0.07 (0.35) in the placebo group. For ΔE1_0 and ΔE2_0 significant differences were found between the groups. Conclusion: In this short-term study, the results showed that a non-hydrogen peroxide bleaching agent has significant whitening effects immediately and 24 h after a single-use treatment

Conformity, reliability and validity of digital dental models created by clinical intraoral scanning and extraoral plaster model digitization workflows

Background: In dentistry, digitization of dental arches with intraoral scanners could one day replace impressions and plaster model digitization processes, if accuracy is clinically sufficient. This study aimed to assess the reliability, validity and conformity of an intraoral scanning procedure (Lythos (c), Ormco) and of two extraoral digitization workflows via alginate impression and plaster model scanning with the D810 (c) (3shape) or the Atos II Triple Scan (c) (GOM) under clinical conditions. Methods: In 20 subjects three consecutive intraoral scans, three alginate and one reference polyether impression were taken of both the upper and lower dental arch, respectively. The digital models created from the corresponding plaster models and the intraoral scans were superimposed with the polyether reference standard by both a global and a local best-fit algorithm. Reliability, validity and conformity of the three digital workflows were assessed via intraclass (ICC) and Lin's concordance correlation coefficients (CCC) as well as analyses according to Bland-Altman. Results: The digital models created from the intraoral scanning procedure were less in agreement with the polyether reference (validity) than those from the extraoral procedures with reduced conformity and reliability. Local numerical deviations from the reference standard were approximately twice as high compared to the extraoral procedures, which showed high conformity and were equivalent and clinically acceptable in terms of reliability and validity. Conclusions: Although the intraoral scanning method with Lythos (c) seems to have drawbacks in terms of reliability, validity and conformity to the indirect alginate methods, all procedures proved to be clinically equivalent for diagnostic purposes

The role of students’ relational identity and autotelic experience for their innovative and continuous use of e-learning

Over the last decades, using e-learning systems as an alternative format of education for traditional classroom has been growing in higher education and due to COVID-19 pandemic, this transition has been unprecedently accelerated. Although there is a large body of research on e-learning, little is known about the extent to which innovative and continuous use of e-learning systems can be influenced by students’ social and motivational factors especially their relational identity and autotelic experience. This study collected data from 400 higher education students through a survey to explore the role of students’ relational identity and autotelic experiences regarding their innovative and continuous use of e-learning systems while considering the mediating role of students’ perception of relatedness. Collected data were analyzed using the structural equation modeling method. The results showed that students' relational identity and autotelic experience significantly influence the innovative and continuous use of e-learning. The results showed that relational identity and autotelic experience positivly associatewith innovative (β = 0.190, t = 3.544; β = 0.405, t = 7.973) and continuous use of e-learning (β = 0.188, t = 3.115; β = 0.344, t = 7.459) and relatedness plays a moderating role between relational identity and continuous use (β = 0.194, t = 4.500, p = 0.000). Relatedness weakens the relationship between relational identity and innovative use of e-learning. However, it reinforces the relationship between relational identity and the continuous use of e-learning. It was found that relatedness strengthens the relationship between autotelic experience with innovative and continuous use of e-learning. The results of this study provide evidence of how students’ social and motivational factors can influence their approaches to the innovative and continuous use of e-learning systems. We discuss these results and provide agenda for future practical and professional work

The consideration of emotional intelligence abilities in event volunteers

The measurement of emotional intelligence abilities is one of the new subjects and important in human behavior studies. According to this matter, purpose of this research is consideration of emotional intelligence abilities in public sport events volunteers in 2011. For this purpose, Bradbury and Cruise's standard questionnaire was completed by present volunteers in event (n=80). The results indicated that 4 levels of emotional intelligence in volunteers are higher than expectational average significantly (p<0.01). Also, priority of emotional intelligence abilities indicated that self-awareness is first priority and social awareness, relationship management and self-management are second, third and fourth priorities in volunteers. Finally, in the basis of parameter, results stated that there is no difference between male and female volunteers emotional intelligence in first Olympia of public sport. According to results of present research and advantages of attention to emotional intelligence and human behavior in organizations, it recommended sport events managers to be more sensitive relative to human behavior abilities in human behavior abilities in human resource (volunteers) under his management. At least, result of this meditation in student's sport is recruitment and development of motivated volunteers for continuous attendance in sport events

Fluoride Ion Release Characteristics of Fluoride-Containing Varnishes—An In Vitro Study

Despite the latest advances in orthodontic treatment, white spot lesions remain a common side effect of fixed appliance therapy. An effective treatment for the prevention of white spot lesions is the use of fluoride-containing products. The aim of the present in vitro study was to check the durability of the tested products for their fluoride release into the surrounding solution. Three varnishes (Protecto CaF2 Nano one-step seal, Bifluorid 12 single dose, and Fluor Protector S) were applied to hydroxyapatite discs and kept in diluted Total Ionic Strength Adjustment Buffer III (TISAB III) solution for fluoride ion release measurement. A group of clear hydroxyapatite discs served as the control group. The carrier discs (N = 40) underwent three thermal cycling runs for 20 days. Before the first run and after each run, the fluoride ion concentration in the solution was measured at appointed times (T) T0, T1, T2, and T3. Fluoride ion release was highest at T1 for all products (median values for Protecto CaF2 Nano one-step seal: 0.09 ppm, Bifluorid 12 single dose: 37.67 ppm, and Fluor Protector S: 3.36 ppm) except for the control group, showing its peak at T0 (0.04 ppm). There was a significant difference between the tested fluoride varnishes at all measurement times. Bifluorid 12 achieved significantly higher fluoride release values than the other products (p < 0.05 at all measurement times). A solitary product application of only once or twice per year, as stated by the manufacturers, cannot be supported

Depth of acid penetration and enamel surface roughness associated with different methods of interproximal enamel reduction

Objectives To assess and compare the enamel surface quality after interproximal enamel reduction (IPR) was performed with different systems and to study the relation between acid penetration depth and enamel surface quality as well as the importance of remineralization. Methods Sixty-five extracted teeth were randomly allocated to five experimental groups: untreated control, manual with New Metal Strips, mechanical with oscillating segment (OS) discs, Safe-Tipped Bur Kit, and the Ortho-Strip, followed by 30 s of polishing with the Softflex system and the Compo-system after treating the tooth with OS discs. Mesial surfaces were demineralized for 24 h and distal surfaces were subjected to interchanging demineralization and remineralization cycles of 24 h each for 18 days. The analysis was carried out by profilometry, scanning electron microscopy, and polarization microscopy. Results After IPR and polishing, enamel roughness was reduced for all systems tested except for the Essix Safe-Tipped Bur Kit. Subsequent demineralization increased enamel roughness in all groups except controls beyond the original level prior to IPR except for IPR with New Metal Strips or Ortho-Strips and subsequent polishing. Cyclic demineralization and remineralization for 18 days yielded a reduction in acid penetration depth and an increase in surface smoothness, which correlated with each other only for controls and treatment with New Metal Strips or Ortho-Strips. Conclusions Manual IPR, using New Metal Strips and, even more, the oscillating IPR system Ortho-Strips, yielded smoother interproximal enamel surfaces and less acid penetration depth than the IPR systems with OS discs and the Safe-Tipped Bur Kit after polishing and 18 days of cyclic demineralization and remineralization. Irrespective of the IPR procedure, proper remineralization of IPR-treated surfaces is advisable to reduce caries susceptibility