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Large-scale construction 3D printing is a promising platform technology that can be leveraged to fabricate structural elements such as columns, piers, pipes, and culverts. In this study, the axial compression and split tensile performance of 3D-printed steel-fiber-reinforced circular elements fabricated with different configurations (hollow, hybrid, mold-cast, and fully 3D-printed) is evaluated. This study further investigates the performance of multi-material circular hybrid elements (3D-printed shells with different backfilled core materials) in an attempt to assess their suitability as a new construction paradigm. The experimental results revealed that the fully 3D-printed steel-fiber-reinforced circular elements exhibited a higher load capacity (up to 36%) and a distinct crack pattern compared to the other configurations. The void ratio of circular elements has varying effects on its axial load capacity depending on the printing material and significantly influences its splitting tensile load capacity. Furthermore, the compatibility between the 3D-printed shell and the cast-in-place core is identified as an influential factor in the structural performance of the hybrid elements. The results suggest a promising construction approach where low-cement material can be utilized as infill material for a cost-effective 3D-printed permanent formwork, offering a viable solution for specific infrastructure development applications. [ABSTRACT FROM AUTHOR]

Nudge theory proposes using subtle interventions to encourage individuals to make better decisions. The aim of this study was to evaluate the effectiveness of the Nudge theory in plaque control and assess caries experience among third-grade primary schoolchildren with refugee and immigrant backgrounds in Mashhad, Iran. Moreover, Afghan and Iranian schoolchildren were compared to assess differences in oral health outcomes. A quasi-experimental field trial was conducted in three public primary schools, comprising 309 participants approximately 9 years old. Interventions were randomly assigned to three schools: School I Messages based on Social Norms (MSN), School II Messages based on Fear of Negative Outcome (MFNO), and School III control group (C). MSN and MFNO received customized motivational video clips at baseline, while C only received Oral hygiene instruction (OHI). All participants received OHI, a brush, and toothpaste. Baseline plaque index (PI) and caries experience in primary and permanent dentition (dmft/DMFT) were recorded. PI was reassessed at two weeks, two months, and six months post-intervention. All data were subjected to statistical analysis. The mean PI decreased significantly in all three groups at the two-week follow-up (p < 0.01). The PI improvements declined over a six-month follow-up period in all groups, and the mean PI difference after six months compared to the pre-intervention was significant only in MSN and MFNO (p < 0.01), while C reverted almost to the pre-study level. Schoolchildren with at least one filled tooth or Iranian nationality showed a greater PI reduction (p < 0.01, p = 0.05). The overall mean ± SD dmft and DMFT were 4.24 ± 2.11 and 1.70 ± 1.24, respectively. Among all the examined participants, 32 (10.40%) individuals were caries-free. The mean dmft was statistically significantly higher in Afghan children than in Iranians (p = 0.01). MSN was more effective on PI reduction in the short term, while MFNO was more long-lasting. Using the Nudge theory via visual aids was more effective in motivating children to perform better oral self-care than solely traditional OHI. [ABSTRACT FROM AUTHOR]

Purpose: Sinonasal malignancies are a rare group of head and neck cancers. We aimed to report the oncological outcomes based on histological types in patients who underwent radiotherapy. Materials and Methods: In this single-institution study, we retrospectively retrieved and analyzed data of patients with sinonasal carcinomas who underwent radiotherapy during 2011-2016 as part of their treatment. The 3-year rate of local, regional, and distant recurrences, and overall survival were evaluated according to the histological type. Results: A total of 28 patients were evaluated in this study, the majority of whom were male (60%). Squamous cell carcinoma (SCC), adenoid cystic carcinoma (ACC), and adenocarcinoma (ADC) were found in 15 patients (53.5%), 8 (28.5%), and 5 (18%), respectively. The highest rates of local and regional recurrences were observed in ACC and SCC, respectively. Distant recurrences were numerically more common in ADC. The 3-year OS was 48%, 50%, and 73% in SCC, ADC, and ACC, respectively. Conclusion: Different histopathologies of sinonasal cancer seem to have different patterns of failure, and this may be considered in the treatment approach. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the association between temporomandibular joint (TMJ) structure and occlusal support status using computed tomography (CT) images. Methods: In this cross-sectional study, the computed tomography (CT) scans of 90 patients were categorized into six groups based on the number of posterior and anterior occlusal support areas (Eichner classification). In CT images, the articular eminence inclination, and glenoid fossa depth and angle were measured. Furthermore, condylar shape and position, and the presence of condyle-flattering or other pathologic changes were recorded. The TMJ variables were compared between different Eichner classification groups. The data were analyzed by paired samples T-tests, one-way ANOVA, and chi-square test (a=0.05). Results: The loss of posterior occlusal support was associated with TMJ flattening and a posterior condylar position (P<0.001). No significant difference was found in the inclination of the articular eminence and depth of the glenoid fossa between different Eichner groups (P>0.05). In patients with unilateral occlusal support, the TMJ on the edentulous side had a significantly lower articular eminence inclination, a greater angle of the glenoid fossa, and a decreased glenoid fossa depth (P<0.001). Conclusions: Loss of posterior occlusal support may lead to changes in the structure of the glenoid fossa, joint space, and condylar position and cause flattening of the condyle. These changes may predispose the joint to degenerative changes. [ABSTRACT FROM AUTHOR]

Background: Head and neck radiotherapy causes side effects such as stomatitis. In vitro studies demonstrated local dose enhancement due to backscatter radiation near metal restorations. The aim of this study was to analyze correlation between number of amalgam restorations with severity of oral mucositis in patients with head and neck radiotherapy. Method and materials: This cross-sectional study was accomplished on 80 patients under head and neck radiotherapy referred to Cancer Institute (Tehran, Iran) in 2014–2015. Severity of mucositis and pain were measured by three examinations according to WHO criteria and visual analogue scale. Descriptive statistics and Spearman's correlation coefficient test used to analyze the data by IBM SPSS statistics V22.0. Results: There was no significant correlation between the number of amalgam restorations and severity of mucositis and pain on second and third examinations. However, severity of mucositis and pain were found to be significantly correlated with radiation dose per session (p = 0.013, rs = 0.276), (p = 0.032, rs = 0.240) and total radiation dose (p < 0.001 rs = 0.393), (p < 0.001, rs = 0.445) on second and third examinations respectively. Conclusion: This study showed that number of dental amalgam restorations have no impact on aggravation of oral mucositis caused by head and neck radiotherapy.

Automated and seamless integration of reinforcement is one of the main unresolved challenges in large-scale additive construction. This study leverages a dual-reinforcement solution consisting of high-dosage steel fiber (up to 2.5% by volume) and short vertical reinforcements as a complementary reinforcement technique for 3D-printed elements. The mechanical performance of the printing material was characterized by measuring the compressive, flexural, and uniaxial tensile strengths of mold-cast specimens. Furthermore, the flexural performance of the plain and fiber-reinforced 3D-printed beams was evaluated in the three main loading directions (X, Y, and Z-directions in-plane). In addition, short vertical threaded reinforcements were inserted into the fiber-reinforced 3D-printed beams tested in the Z-direction. The experimental results revealed the superior flexural performance of the fiber-reinforced beams loaded in the longitudinal directions (X and Y). Moreover, the threaded reinforcement significantly increases the flexural strength and ductility of beams loaded along the interface, compared to the control. Overall, the proposed dual-reinforcement approach, which exhibited notably less porosity compared to the mold-cast counterpart, holds great potential as a reinforcement solution for 3D-printed structures without the need for manual operations. [ABSTRACT FROM AUTHOR]

Objective: Cone beam computed tomography (CBCT) is an imaging modality that has recently gained increasing popularity for dental imaging. This study aimed to investigate the usage of CBCT imaging among Iranian Association of Endodontists members using an online survey. Methods: Iranian endodontic practitioners were recruited to participate in the study. A web-based questionnaire was designed and sent to 328 endodontists. The questionnaire was available for a one-month long period during November 2019. The questionnaire included basic demographic details of the participants and questions related to CBCT application in endodontic treatment procedures. The validity and reliability of the questionnaire were assessed by expert endodontists. The chi-square test was used for data analysis, and a p-value less than 0.05 was considered statistically significant. Results: A total of 101 participants completed the survey, giving an overall completed response rate of 30.8%. Ninetyfour percent of participants (n=95) used CBCT imaging in their practice. There were significant differences in some variables between endodontists who frequently prescribed CBCT as compared to those who rarely prescribed it (P<0.05). CBCT was prescribed more frequently by endodontists who received training in CBCT usage, those performing periapical surgeries, and those using magnification in their practice. Conclusions: The survey indicated that CBCT technology is widely used among Iranian endodontists particularly if they have already received the required training. The most common indications for CBCT were detecting vertical root fracture, teeth with complex anatomy and additional canals, and root resorption. [ABSTRACT FROM AUTHOR]