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Purpose: To assess the influence of applicator tip diameter on the inclusion of porosities in three different flowable resin composites. Methods: The initial porosity of three syringes [Filtek Supreme XTE Flowable (XTE), Grandio Flow (GRF), Gradia Direct Flo (GDF)] was determined by 3D tomography. 25 samples per syringe, i.e. 75 samples in total, were prepared using five applicator tips of different diameters (n= 5). The porosity of the 75 samples was assessed by 3D tomography. Results: For each of the materials, the applicator tips, irrespective of type, all generated an increase in the average porosity percentage compared to the initial porosity of the syringes. For XTE and GRF, the applicator tips, irrespective of type, all generated a decrease in the average porosity volume compared to the initial average porosity volume in their respective syringes. Conversely, for GDF the average porosity volume of the samples was increased. Furthermore, for each of the materials, varying the diameter of the applicator tips had no significant influence on the porosity percentage and volume. Using the present study conditions, the applicator tip generated a variation in the initial porosity of the materials; however, the diameter of the tip had no influence on said variation. [ABSTRACT FROM AUTHOR]

Amelogenesis imperfecta (AI) is a hereditary disorder caused by mutations of genes primarily involved in the enamel formation. Several different types of AI have been identified, based on the phenotype and on the mode of inheritance. Regardless of the type, the dental treatment tends to be the same, favoring the complete removal of the compromised enamel late in the patient's life. With the new dentistry guidelines that orient clinicians towards minimal invasiveness, it should be mandatory to intercept patients affected by AI earlier, not only to protect the dentition from further degradation but also to help patients improve their self-esteem. This article examines the restorative dentistry performed on a 24-year-old Caucasian female suffering from the hypoplastic type of AI, using only adhesive procedures. Due to the complex needs of the patient, an interdisciplinary approach was followed, involving orthodontics, periodontics, and restorative dentistry. A full-mouth adhesive rehabilitation was achieved by means of direct composite restorations, veneer/onlays and facial/palatal veneers. No elective endodontic therapy was necessary for restorative purposes. The esthetics, mechanics, and biological success were achieved and maintained. The bond to the enamel did not show signs of degradation (eg, discoloration or infiltration) even after 5 years of function. This is encouraging as it shows that adhesive techniques may be a reliable approach even in the presence of a compromised enamel layer. [ABSTRACT FROM AUTHOR]

Despite major instrumental developments over the last decade, endodontic files are still not infallible. It is well known that NiTi rotary files can break without any visible sign of deformation. Instrument breakage under combined flexion-torsion loading is still common in clinical practice. Unfortunately, breakage of this type of instrument mainly occurs in narrow canals, through pinching in the apical region. When such an incident occurs, the endodontist must adopt a debris retrieval strategy that is both stressful and not guaranteed success. This study proposes a new method for experimental damage detection leading to the fracture of Ni-Ti shape memory alloy endodontic files. It is based on the acoustic emission (AE) technique and mechanical parameters measured in real-time and image analysis. It has been shown that the AE results correlate with the damage observations and torque and force measurements recorded during the tests. Having carried out numerous root canal treatment on resin blocks, it appears that this new detection and analysis technique can be used to analyze and anticipate the first signs of damage leading to endodontic file failure. The technological development of such a method, at the level of the engine itself, associated with the act in service procedure, would constitute a revolution in the field of endodontics., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jeanne Davril reports equipment, drugs, or supplies was provided by Micro-Mega SA. Marin Vincent has patent #FR3127686 issued to Marin Vincent. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: This study compared the storage modulus (E'), the loss modulus (E'') and the loss tangent (tan δ) of various flowable resin composites., Material and Methods: Grandio Flow (GRF), GrandioSo Heavy Flow (GHF), Filtek Supreme XTE (XTE) and Filtek Bulk Fill (BUL) flowable resins and Clinpro Sealant (CLI) ultra-flowable pit and fissure sealant resin were used. 25 samples were tested using a dynamical mechanical thermal analysis system in bending mode. Measurements were taken within a temperature range of 10 to 55°C. The results were statistically analyzed using mixed-effect and repeated-measure analysis of variance followed by paired multiple comparisons., Results: For all the materials, the E' values decrease with temperature, whereas the tan δ values increase. Irrespective of the temperature, GHF and GRF present E' and E'' values significantly higher than all the other materials and CLI presents values significantly lower than all the other materials. Observation of the values for all the materials reveals a linear progression of the tan δ values with temperature., Conclusions: A variation in temperature within a physiological range generates modifications in mechanical properties without damaging the material, however. Filler content in volume terms appears to be the crucial parameter in the mechanical behavior of tested materials. Key words: Dynamic mechanical thermal analysis, elastic modulus, filler content, flowable resin composites, loss modulus, loss tangent., Competing Interests: The authors declare that they have no conflict of interest.