The purpose of this study was to characterize the surface roughness, the microstructure, and mechanical properties of four prefabricated zirconia pediatric crowns. Ten prefabricated crowns from four different manufacturers (Cheng Crowns Zirconia), (EZCrowns), (NuSmile ZR), and (Zirconia Pediatric Crowns) were included in this study. The surface roughness parameters (Sa, Sq, Sz, Sc, and Sv) of all samples were studied by optical profilometry and then the microstructure was studied by Raman spectroscopy. Then, all samples were embedded in epoxy resin and after metallographic polishing, the Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), Vickers hardness (HV), and fracture toughness (KIC) were identified by the Instrumented Indentation Testing (IIT). All data were statistically analyzed by a one-way ANOVA and a Tukey multiple comparison test at α = 0.05. Only the tetragonal phase of zirconia for all materials tested was identified after Raman analysis. However, statistically significant differences were found among the surface roughness parameters, HV and KIC, while no differences were allocated for HΜ, EIT, and ηΙΤ. Although the materials tested shared a similar microstructure, significant differences in surface roughness parameters HV and KIC were identified and, thus, differences in their clinical performance were anticipated.
BackgroundFor periodontal treatment, the full mouth disinfection approach suggests disinfection of oral soft tissues, such as tongue and tonsils concomitant to scaling and root planning since patients might benefit from treatment of these oral niches either. Periodontopathogenes in tonsillar tissue support this hypothesis. This prospective controlled clinical study investigated the change in the oral flora of patients who underwent tonsillectomy. Pockets were tested for eleven bacterial species before and six weeks after the surgical intervention.MethodsFifty generally healthy adults were included in this study. The test group consisted of 25 patients with tonsillectomy. The control group included 25 patients with otorhinolarynologic surgery without involvement of the oral cavity. Clinical parameters such as probing pocket depth, bleeding-on-probing index and plaque index were registered the evening before surgery. Also bacterial samples from the gingival sulcus and dorsum linguae were taken, and an additional sample from the removed tonsils in the test group. Six weeks after the intervention microbial samples of pockets and tongue were taken again. Data were tested for significant differences using Wilcoxon rank and Whitney-u-test.ResultsNo relevant intra- or intergroup differences were found for the change of the eleven investigated species.ConclusionBased on the results of the present study, tonsillectomy does not seem to have an immediate relevant effect on the bacterial flora of tongue or periodontium. This study design was approved by the ethical committee of Zurich (KEK-ZH-Nr.2013–0419).Trial registrationThe trial was retrospectively registered in the German Clinical Trials Register (DRK00014077) on February 20, 2018.
L’endocardite infectieuse est une maladie rare pendant l’enfance. En Suisse, ces dernières dix années, environ 5-7 enfants (<18 ans) par an étaient concernés, la tendance étant croissante. Le diagnostic d’endocardite infectieuse se base sur (1) des symptômes cliniques comme la fièvre, la détérioration de l’état général, des difficultés à téter, une diminution de la résistance physique, (2) la mise en évidence de germes à l’hémoculture et (3) l’échocardiographie; selon les critères modifiée de Dukes le diagnostic est considéré soit «définitif» soit «possible».
Aim: To compare the mechanical properties of four different types of contemporary fissure sealants before and after water storage employing a modern instrumented indentation testing (IIT) method. Materials and methods: Four different types of materials used in everyday practice were deliberately selected. Fissurit (FIS) is a highly filled resin, Embrace (EMB) is a bisphenol A (BPA)-free unfilled resin, Helioseal (HEL) is an unfilled resin, and Riva Protect (RIV) is a glass-ionomer material. Six cylindrical specimens from each material were prepared (h: 3 mm, Ø: 15 mm), and Martens hardness (HM), elastic modulus (E IT ), elastic index (η IT ), and Vickers hardness (HV) were determined employing an IIT machine according to International Organization for Standardization (ISO) 14577:2015. Then, the samples were stored in water at 37 °C for 48 hours and measured again at the same surface. The mechanical properties tested (HM, E IT , η IT , and HV) were statistically analyzed by two-way repeated measurements analysis of variance (ANOVA) employing materials and conditions as discriminating variables. Statistically significant differences were identified by Tukey's post hoc multiple comparison test. In all cases, a 95% level of significance was set (p = 0.05). Results: Statistically significant differences in selected mechanical properties were allocated among materials tested. The artificial aging had a detrimental effect on HM, E IT , and HV apart from η IT for FIS, EMB, and HEL. In contrast, no significant differences were identified for RIV before and after water storage for all aforementioned properties apart from η IT . Conclusion: Significant differences were identified in mechanical properties among materials tested and thus differences in their clinical behavior are anticipated. Clinical significance: This study contributes to the understanding of the mechanical properties of different dental sealants with respect to water contact, which may influence the choice by the therapist.
Die infektiöse Endokarditis ist im Kindesalter eine komplikationsreiche Erkrankung. In der Schweiz waren in den letzten zehn Jahren etwa 5-7 Kinder (< 18 Jahre) pro Jahr davon betroffen, wobei die Tendenz zunehmend ist.
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