Background Stomach cancer is a major health problem in many countries. Understanding the current burden of stomach cancer and the differential trends across various locations is essential for formulating effective preventive strategies. We report on the incidence, mortality, and disability-adjusted life-years (DALYs) due to stomach cancer in 195 countries and territories from 21 regions between 1990 and 2017.Methods Estimates from GBD 2017 were used to analyse the incidence, mortality, and DALYs due to stomach cancer at the global, regional, and national levels. The rates were standardised to the GBD world population and reported per 100 000 population as age-standardised incidence rates, age-standardised death rates, and age-standardised DALY rates. All estimates were generated with 95% uncertainty intervals (UIs).Findings In 2017, more than 1·22 million (95% UI 1·19-1·25) incident cases of stomach cancer occurred worldwide, and nearly 865 000 people (848 000-885 000) died of stomach cancer, contributing to 19·1 million (18·7-19·6) DALYs. The highest age-standardised incidence rates in 2017 were seen in the high-income Asia Pacific (29·5, 28·2-31·0 per 100 000 population) and east Asia (28·6, 27·3-30·0 per 100 000 population) regions, with nearly half of the global incident cases occurring in China. Compared with 1990, in 2017 more than 356 000 more incident cases of stomach cancer were estimated, leading to nearly 96 000 more deaths. Despite the increase in absolute numbers, the worldwide age-standardised rates of stomach cancer (incidence, deaths, and DALYs) have declined since 1990. The drop in the disease burden was associated with improved Socio-demographic Index. Globally, 38·2% (21·1-57·8) of the agestandardised DALYs were attributable to high-sodium diet in both sexes combined, and 24·5% (20·0-28·9) of the age-standardised DALYs were attributable to smoking in males.Interpretation Our findings provide insight into the changing burden of stomach cancer, which is useful in planning local strategies and monitoring their progress. To this end, specific local strategies should be tailored to each country's risk factor profile. Beyond the current decline in age-standardised incidence and death rates, a decrease in the absolute number of cases and deaths will be possible if the burden in east Asia, where currently almost half of the incident cases and deaths occur, is further reduced.

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Recent evidence suggests that, in some foci, elimination of onchocerciasis from Africa may be feasible with mass drug administration (MDA) of ivermectin. To achieve continental elimination of transmission, mapping surveys will need to be conducted across all implementation units (IUs) for which endemicity status is currently unknown. Using boosted regression tree models with optimised hyperparameter selection, we estimated environmental suitability for onchocerciasis at the 5 × 5-km resolution across Africa. In order to classify IUs that include locations that are environmentally suitable, we used receiver operating characteristic (ROC) analysis to identify an optimal threshold for suitability concordant with locations where onchocerciasis has been previously detected. This threshold value was then used to classify IUs (more suitable or less suitable) based on the location within the IU with the largest mean prediction. Mean estimates of environmental suitability suggest large areas across West and Central Africa, as well as focal areas of East Africa, are suitable for onchocerciasis transmission, consistent with the presence of current control and elimination of transmission efforts. The ROC analysis identified a mean environmental suitability index of 0·71 as a threshold to classify based on the location with the largest mean prediction within the IU. Of the IUs considered for mapping surveys, 50·2% exceed this threshold for suitability in at least one 5 × 5-km location. The formidable scale of data collection required to map onchocerciasis endemicity across the African continent presents an opportunity to use spatial data to identify areas likely to be suitable for onchocerciasis transmission. National onchocerciasis elimination programmes may wish to consider prioritising these IUs for mapping surveys as human resources, laboratory capacity, and programmatic schedules may constrain survey implementation, and possibly delaying MDA initiation in areas that would ultimately qualify.

Background and Objectives: Endodontic sealers are used to fill the gap between the root filling material and canal walls. Retrievability is an important requirement for sealers and root filling materials in non-surgical endodontic retreatment. This study sought to assess the retreatability of fluoride varnish, AH 26 and Mineral Trioxide Aggregate (MTA)-based sealers using Cone-Beam Computed Tomography (CBCT). Materials and Methods: This in vitro, experimental study evaluated 45 extracted single-rooted, single-canal human mandibular premolars. Teeth with cracks or fracture were excluded. The root canals were prepared using ProTaper Universal rotary system up to size F4 according to the manufacturer’s instructions. The teeth were then randomly divided into three groups of 5% fluoride varnish, AH 26 and MTA Fillapex. CBCT scans were obtained of the teeth with 200 μm voxel size. MATLAB R2012 software was used to quantify the amount of sealer remaining in the canal. Two observers evaluated the images. Data were analyzed using SPSS via the Kruskal-Wallis and Mann Whitney tests. Results: The amount of sealer remaining in the root canals was significantly different among the three groups (P<0.05). The amount of AH 26 sealer remaining in the root canals (1.91±1.46) was significantly greater than MTA Fillapex (0.62±0.26) and fluoride varnish, but the latter two were not significantly different in this respect (P>0.05). Conclusion: Considering the adequate adhesion of fluoride varnish to dentin, its cariostatic effect and low cost, it seems to be a suitable alternative to the commonly used endodontic sealers.

Background: Inadequate retention and gradual debonding of intracanal post from root dentin is a major cause of failure of endodontically treated teeth restored with fiber post. Main body: This study aimed to assess the effect of surface treatment of quartz fiber posts with different powers and motion directions of Er,Cr:YSGG laser on their pull-out bond strength to root dentin in endodontically treated premolar teeth. In this study, 105 fiber posts were divided into 7 groups according to their surface treatment with different powers of Er,Cr:YSGG laser at 2780 nm wavelength, 20 Hz frequency and 150 μs pulse duration in circumferential (C) or longitudinal (L) motion directions: Control group (no treatment), 0.5 W laser in longitudinally (L0.5), 1.0 W laser in longitudinally (L1), 1.5 W laser in longitudinally (L1.5), 0.5 W laser in circumferentially (C0.5), 1.0 W laser in circumferentially (C1) and 1.5 W laser in circumferentially (C1.5). After cementation, pull-out bond strength was measured in Newton (N). Each sample was inspected under a stereomicroscope at × 25 magnification to determine the mode of failure. Two samples of each group were inspected under a scanning electron microscope (SEM). Data were analyzed using two-way ANOVA and Tukey's test with significant level of 0.05. The pull-out bond strength of 0.5 W groups had significant differences with the control group (P = 0.009). The bond strength of 1.0 W and 1.5 W groups were not significantly different (P = 0.630) but were higher than the control and 0.5 W groups (P < 0.001). Motion direction of laser irradiation had no significant effect on the bond strength (P = 0.384). The interaction effect of power and motion direction of laser irradiation had no significant effect on the bond strength (P = 0.092). Conclusion: Fiber posts treated with 0.5, 1.0 and 1.5 W Er,Cr:YSGG laser showed higher bond strength to dentin compared to posts with no surface treatment. However, the motion directions of laser irradiation had no significant effect on the bond strength. In order to minimize damage to post surface and achieving maximum bond strength, longitudinal surface treatment of posts with 1.0 W power of Er,Cr:YSGG laser is recommended.