Fracture Resistance of Zirconia Restorations with Four Different Framework Designs.

Objectives: This study assessed the fracture resistance of zirconia crowns with four framework designs, fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Materials and Methods: In this experimental study, a maxillary central incisor was prepared and scanned with a CAD/CAM scanner, and 40 frameworks with 4 designs (N=10) were fabricated as follows: simple core, dentine core with a design similar to dentine, 3mm trestle design collar in the lingual aspect with proximal buttresses, and monolithic or full-contour. After porcelain applying and 20h immersion in distilled water (37°C), crowns were cemented on metal dies using zinc phosphate cement. Fracture resistance was measured by a universal testing machine. Data were analyzed with one-way ANOVA (alpha=0.05). Results: Fracture resistance was maximum in the monolithic group, followed by the dentine core, trestle design, and simple core groups, respectively. The mean fracture resistance of the monolithic group was significantly higher than that of the simple core group (P<0.005). Conclusion: Zirconia restorations with frameworks that provided higher and more support for porcelain, showed increased fracture resistance.

Validity and reliability of tooth color selection by smartphone photography and software applications.

Aim: This study assessed the validity and reliability of color selection by smartphone photography using two smartphone applications and Adobe Photoshop software. Settings and Design: In vitro comparative study. Materials and Methods: The validity and reliability of dental tooth shade recognition (DTSR), Chromatcher, and Adobe Photoshop were evaluated for color selection of shade tabs. The iPhone 7 camera in automatic mode was used for photography. Images were captured using Smile Lite with/without polarized filter and with camera flash. To assess the reliability, nine Vita Lumin Vacuum shade tabs were chosen and each was photographed for 10 times using Smile Lite. The reliability of DTSR, Chromatcher, and Photoshop in shade-taking was calculated. To assess their validity, 16 shade tabs of Vita Lumin Vacuum and 26 shade tabs of Vita 3D Master were photographed using the aforementioned lighting conditions. The color of photographs was calibrated and shade-taking was performed and compared with the shade suggested by SpectroShade as reference. Statistical Analysis Used: Data were analyzed using Two-way analysis of variance and Bonferroni post hoc test. Results: The reliability of Photoshop, DTSR, and Chromatcher was 98.88%, 63.3%, and 100%, respectively. The validity of Photoshop was significantly higher than other software programs (P < 0.05). Chromatcher had higher validity than DTSR (P < 0.05). Conclusion: Shade-taking by calibrated smartphone pictures and Adobe Photoshop has high validity and reliability.

Evaluation of the Effect of Buccolingual and Apicocoronal Positions of Dental Implants on Stress and Strain in Alveolar Bone by Finite Element Analysis.

OBJECTIVES: The position of dental implants in the alveolar bone can affect the surrounding bone from biomechanical and biological aspects. The purpose of this study was to evaluate the effect of implant position on stress and strain distribution in the surrounding bone by using finite element analysis (FEA). MATERIALS AND METHODS: Thirteen computerized models of a 3.8-mm-diameter XiVE implant with the abutment and crown of a mandibular second premolar in a mandibular bone segment were designed. In the reference model, the implant was placed at the center of the alveolar ridge with its crest module located above the alveolar crest. In the other models, the implants were positioned buccally, lingually, coronally or apically by 0.5, 1 or 1.5mm. By using the ANSYS software program, a 100-N load was applied to the buccal cusp parallel to and at a 30-degree angle relative to the longitudinal axis of the fixture. The models were analyzed in terms of the distribution of stress and strain in the bone. RESULTS: The different implant positions induced nonlinear stress and strain changes in the bone. The central, 1.5-mm apical, and 1.5-mm coronal implant positions induced high amounts of stress and strain under off-axial loads. CONCLUSIONS: Within the limitations of this study, the results showed that the stress and strain in the bone around the implant undergo small nonlinear changes with buccolingual and apicocoronal shifting of the implant and can be affected by the configuration of the implant in contact with the bone.

Association between FTO gene polymorphisms and type 2 diabetes mellitus, serum levels of apelin and androgen hormones among Iranian obese women.

BACKGROUND AND AIMS: Recent studies show that FTO single nucleotide polymorphisms (SNPs) are associated with obesity and type 2 diabetes mellitus (T2DM). On the other hand, many animal models and clinical studies have demonstrated that apelin, an adipocytokine, is related to the obesity and T2DM. Additionally, obese women are at risk of Hyperandrogenemia. So, the aim of this study was to investigate the relationship between FTO variants (rs763967273, rs759031579, rs141115189, rs9926289, rs76804286 and rs9939609) with T2DM, serum apelin and androgenic hormones in Iranian obese women. SUBJECTS AND METHODS: 197 obese women (123 women with T2DM and 74 women as healthy control) were participated in this study. Anthropometrical and biochemical characteristics were measured. Serum apelin and androgen hormones levels were determined in 66 subjects consisting of 33 cases and 33 controls. PCR were carried out and subsequently, the PCR production was genotyped by Sanger sequencing assay. RESULTS: Our observations showed that all SNPs are related to T2DM. The rs9926289 FTO variant had a strong association with serum apelin and dehydroepiandrosterone-sulfate levels (P=0.04 and P=0.03, respectively) among SNPs. In addition, apelin and androgenic hormones were correlated with T2DM. Two polymorphisms including rs9939609 and rs9926289 had a strong Linkage disequilibrium (r2=1). CONCLUSION: FTO variants not only were associated with T2DM, but also some variants had a strong association with apelin and androgenic hormones profile.

Beijing strains of Mycobacterium tuberculosis in smear-positive tuberculosis patients in North-West and West of Iran.

BACKGROUND: Tuberculosis (TB) is the leading cause of morbidity and mortality among chronic infectious diseases. The goal of this cross-sectional study (2012-2014) was to examine the prevalence of Mycobacterium TB (MTB) Beijing strains in regions near the Iranian border and to identify any epidemiological links. MATERIALS AND METHODS: To this end, MTB isolates were harvested, from 64 HIV-negative, pulmonary smear-positive TB patients from the Iranian border provinces of East Azerbaijan (North-West), Kurdistan (West), and Kermanshah (West) (2012-2014). Isolates were subjected to restriction fragment length polymorphism (RFLP) analysis, using the insertion sequence IS6110 as a probe (IS6110 RFLP), and drug susceptibility testing by the proportion method. We gathered demographic and clinical data using a questionnaire and reviewing patient records. Results were analyzed with Gel Compare II 6.6 and SPSS-18. RESULTS: The mean age of the patients was 54.4 years and 46.9% were male. The prevalence of Beijing strains among the isolates was 9.4% (17.6% in the Western provinces and 0% in East Azerbaijan). There was a statistically significant relationship between the Beijing strains and drug resistance and also between these strains, and the recurrence of TB in patients that had previously received treatment (P = 0.02 and P = 0.04, respectively). CONCLUSIONS: Finally, the prevalence of Beijing strains in Western Iran was greater than expected. Our results therefore indicate that regional and cross-border tracing may be necessary to control spread of this organism.

Comparative proteomic analysis of canola leaves under salinity stress.

Although canola is a moderately salt-tolerant species, its growth, seed yield, and oil production are markedly reduced under salt stress, particularly during the early vegetative growth stage. To identify the mechanisms of salt responsiveness in canola, the proteins expressed in the second and third newly developed leaves of salt-tolerant, Hyola 308, and salt-sensitive, Sarigol, cultivars were analyzed. Plants were exposed to 0, 175, and 350 mM NaCl during the vegetative stage. An increase in the Na content and a reduction in growth were observed in the third leaves compared to the second leaves. The accumulation of Na was more pronounced in the salt-sensitive compared with the salt-tolerant genotype. Out of 900 protein spots detected on 2-DE gels, 44 and 31 proteins were differentially expressed in the tolerant and susceptible genotypes, respectively. Cluster analysis based on the expression level of total and responsive proteins indicated that the second leaves had a discriminator role between the two genotypes at both salinity levels. Using MS analysis, 46 proteins could be identified including proteins involved in responses to oxidative stress, energy production, electron transport, translation, and photosynthesis. Our results suggest that these proteins might play roles in canola adaptation to salt stress.

The effect of recasting on bond strength between porcelain and base-metal alloys.

PURPOSE: Long-term success of metal ceramic restorations depends on metal ceramic bond strength. The purpose of this study was to determine whether recasting of base-metal alloys has any effect on metal ceramic bond strength. MATERIALS AND METHODS: Super Cast and Verabond base-metal alloys were used to cast 260 wax patterns. The alloy specimens were equally divided into five groups and cast as: group A 0.0%, B 25%, C 50%, D 75%, and E 100% once-cast alloy. Each group was divided into two subgroups: the first group was cast with Super Cast and the second with Verabond. In each subgroup half of the cast alloys were veneered with Vita VMK 68 and the others with Ceramco 3. RESULTS: Recasting decreased bond strength (p < 0.006) when used for 50% once-cast alloy. Group E with 100% new Super Cast alloy veneered with Vita VMK 68 porcelain had the highest bond strength (30.75 ± 9.58 MPa), and group B including 25% new and 75% recast Super Cast alloy veneered with the same porcelain had the lowest bond strength (21.72 ± 5.19 MPa). CONCLUSIONS: By adding over 50% once-cast alloy in base-metal alloys, metal-ceramic bond strength decreases significantly.