ABSTRACT
The treatment of severe molar-incisor hypomineralisation (MIH) is often a challenge for both the patient and the practitioner. Factors such as hypersensitivity, pulpitis, partially erupted molars, and reduced adhesive bond strength make dental work more difficult and reduce long-term success. It is particularly important for everyday practice that there is a wide range of temporary restoration options even for teeth that are difficult to restore. The present paper deals with the practical recommendations for the therapy of MIH. Therapy recommendations from the European Academy of Pediatric Dentistry (EAPD) and the Würzburg MIH Concept are considered. In addition, established therapy methods from the Universities of Bern and Zurich will be discussed.
Subject(s)
Dental Enamel Hypoplasia , Incisor , Child , Dental Enamel Hypoplasia/therapy , Humans , Molar , Prevalence , Private PracticeABSTRACT
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.
ABSTRACT
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 (EIT), elastic index (ηIT), 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, EIT, ηIT, 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, EIT, and HV apart from ηIT 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 ηIT. 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.
