Assessment of wear characteristics, longevity and stiffness of Essix-type retainers.

OBJECTIVE: To compare four commercially available Essix-type retainers in terms of longevity, wear characteristics, stiffness and their range of rigidity. MATERIALS AND METHODS: An in vitro study was conducted at Queen Mary University of London. Four groups of thermoplastic materials were included: Duran (PETG), Essix C + (Polypropylene), Vivera and Zendura (Polyurethane). A working typodont was fabricated to evaluate surface wear characteristics using a wear machine with a customized jig. Retainers were measured for tensile test, and water absorption was measured at five different time points up to 6 months after initial immersion in two different physical states and two different solutions. Hydrolytic degradation was also evaluated using FTIR spectroscopy. RESULTS: Essix C + was the most flexible retainer with Vivera the stiffest material. Zendura and Essix C + had the most surface wear (413 µm ± 80 and 652 µm ± 12, respectively) with absorption rates of up to 15 wt% in artificial saliva occurring with Zendura. Only Essix C + displayed signs of degradation following water absorption. CONCLUSIONS: All materials had characteristic levels of flexibility and were susceptible to water absorption. Duran 1.5 mm performed similarly to Vivera in relation to stiffness and wear properties. While Zendura and Vivera have similar chemical structures, they exhibited differences concerning wear resistance and water absorption. Further clinical research evaluating the clinical relevance of these laboratory findings is required. CLINICAL RELEVANCE: Characteristic patterns of wear and rigidity of four commercially available Essix-type retainers were observed. This information should help in the tailoring of retainer material on a case-by-case basis considering treatment-related factors and patient characteristics including parafunctional habits.

"Comparing the effectiveness, acceptability and oral hygiene status between vacuum formed retainer and Begg's retainer": a pilot study.

BACKGROUND: Recently, Vacuum formed retainers (VFRs) are preferred as an Orthodontic retention appliance over conventional Begg's retainers. Very few studies have been conducted between VFRs and Begg's retainers. Hence, this study aims at assessing the effectiveness, oral hygiene and acceptability between VFRs and Begg's retainers with a follow up period of 1 year. METHODS: Eighty patients who completed fixed Orthodontic treatment were included. Retainers were delivered on the same day of debonding. Retainer 1/ R1 stands for VFRs and Retainer 2/ R2 stands for Begg's retainers. The retainers were randomly allocated to both the arches. 40 VFRs and Begg's retainers in maxillary and mandibular arch were given respectively. Effectiveness, oral hygiene condition were performed at T0 (After debonding), T1 (3 months after using retainers), T2 (6 months after using retainers), T3 (9 months after using retainers), T4 (12 months after using retainers) follow up stages, except the feedback form and the breakage of retainers that were filled at T4 stage. RESULTS: Both R1 and R2 retainers showed improvement in teeth alignment in both the arches at follow up stages. Interproximal contacts in maxillary and mandibular arch with VFRs and Begg's retainers improved to 77.5% and 82.5% respectively. Considering the marginal ridge, Begg's retainers and VFRs showed 95%, 55% increased proportion at T4 respectively (p < 0.05). Patients wearing Beggs's retainers had significantly better (p < 0.05) oral hygiene status. Significant differences were observed with Begg's retainers in teeth biting, whereas no significant difference was found with fitting of appliance (p = 0.180) and gingival irritation (p = 1.000). VFRs were well accepted aesthetically that was significant. Retainers were prone to breakage but was not significant (p = 0.162). CONCLUSION: Begg's wrap around retainers maintain good oral hygiene, improve the teeth alignment, interproximal contact and marginal ridges post Orthodontic treatment with better fitting of the appliance. VFRs are also preferred as they are good in maintaining proper teeth alignment with progressive improvement in the interproximal contacts and are aesthetically pleasing.

Malaria in Austria : A retrospective analysis of malaria cases diagnosed at a reference center in 2010-2020.

BACKGROUND: Although malaria is not endemic to Austria, each year infections are imported by travellers, migrants and refugees. This study aims to provide an overview of malaria cases diagnosed at an Austrian institute for tropical medicine between 2010 and 2020. METHODS: A retrospective, descriptive study was conducted based on the data of malaria cases confirmed at the Institute of Specific Prophylaxis and Tropical Medicine of the Medical University of Vienna. Laboratory diagnostics included microscopy, polymerase chain reaction (PCR) and real-time quantitative PCR. RESULTS: Overall, 122 cases were identified. Annual case numbers were consistently higher from 2016 to 2020 than during the first half of the decade. Most malaria cases were diagnosed during summer and early autumn. This seasonal trend was not observed during the year 2020. With 55.1% (65/118) Plasmodium falciparum was the most common species, followed by Plasmodium vivax (19.5%, 23/118). The majority of patients were male (71.1%, 86/121) and the median age was 34.5 years (interquartile range, IQR 22.5-47.0 years). With a median age of 20.0 years (IQR 14.0-32.0 years), patients with P. vivax infections were younger than those infected with other Plasmodium species. Moreover, they were mostly male (82.6%, 19/23). CONCLUSION: From 2010 to 2020, the number of malaria cases diagnosed at the center increased. Growing international mobility and changing travel behavior could at least partly be responsible for this trend and there are indications that particularly P. vivax infections were imported by migrants and refugees.

A comparative study of Plasmodium falciparum histidine-rich protein 2 (PfHRP2) blood levels and peripheral blood parasitemia as parameters of disease severity in individuals with imported falciparum malaria.

BACKGROUND: In falciparum malaria the total parasite biomass can be estimated by blood levels of histidine-rich protein 2 (PfHRP2), a Plasmodium falciparum-specific protein, which has been widely studied in malaria-endemic regions. This study investigates the usefulness of PfHRP2 as marker for disease severity in imported falciparum malaria. METHODS: A retrospective cohort analysis was done in 145 patients with imported falciparum malaria. Associations between PfHRP2, malaria disease severity and classic parameters of disease severity were examined by statistical analyses. Patients with different travel purposes were examined in two groups: visiting friends and relatives (VFRs) and other travel purposes (mainly tourists). RESULTS: High PfHRP2 levels were clearly associated with disease severity. VFRs status showed to be an independent determinant protecting against severe malaria. At similar PfHRP2 levels VFRs patients had significantly lower levels of peripheral blood parasitemia compared to other patients. CONCLUSION: Our study confirms the association between PfHRP2 and disease severity in patients with imported falciparum malaria, but for proper interpretation of PfHRP2 levels as disease severity marker in travellers, the possible presence of pre-existing acquired anti-malarial immunity should be taken into account as the correlation between PfHRP2 levels and disease severity differed significantly between VFRs patients and patients with other travel purposes.

Imported malaria in children in Madrid, Spain, 2007-2013.

BACKGROUND: The majority of malaria cases diagnosed in Europe in the last few years have occurred in people living in non-endemic areas travelling back to their home country to visit friends and relatives (VFRs). Children account for 15-20% of imported malaria, with known higher risk of severe disease. MATERIAL AND METHODS: A retrospective multicentre study was conducted in 24 hospitals in Madrid (Spain) including patients under 16 years diagnosed with malaria (2007-2013). RESULTS: A total of 149 episodes in 147 children were reported. Plasmodium falciparum was the species most commonly isolated. Twenty-five patients developed severe malaria and there was one death related to malaria. VFR accounted for 45.8% of our children. Only 17 VFRs had received prophylaxis, and 4 of them taken appropriately. They presented more frequently with fever (98% vs. 69%), a longer time with fever (55 vs. 26%), delay in diagnosis of more than three days (62 vs. 37%), and more thrombocytopenia (65 vs. 33%) than non-VFRs, and with significant differences (p<0.05). CONCLUSIONS: VFRs represent a large proportion of imported malaria cases in our study. They seldom took adequate prophylaxis, and delayed the visit to the physician, increasing the length of fever and subsequent delaying in diagnosis. Appropriate preventive measures, such as education and pre-travel advices should be taken in this population.

Travel-associated illness trends and clusters, 2000-2010.

Longitudinal data examining travel-associated illness patterns are lacking. To address this need and determine trends and clusters in travel-related illness, we examined data for 2000-2010, prospectively collected for 42,223 ill travelers by 18 GeoSentinel sites. The most common destinations from which ill travelers returned were sub-Saharan Africa (26%), Southeast Asia (17%), south-central Asia (15%), and South America (10%). The proportion who traveled for tourism decreased significantly, and the proportion who traveled to visit friends and relatives increased. Among travelers returning from malaria-endemic regions, the proportionate morbidity (PM) for malaria decreased; in contrast, the PM trends for enteric fever and dengue (excluding a 2002 peak) increased. Case clustering was detected for malaria (Africa 2000, 2007), dengue (Thailand 2002, India 2003), and enteric fever (Nepal 2009). This multisite longitudinal analysis highlights the utility of sentinel surveillance of travelers for contributing information on disease activity trends and an evidence base for travel medicine recommendations.