Objective: To evaluate the effect of preheating on the microleakage and surface hardness of resin composites in the treatment of pit-and-fissure caries with various widths, as measured by an intraoral scanner.
Methods: A total of 153 L-shaped cavities with different widths (1 mm, 1.6 mm and 2 mm) were prepared on the buccal or palatal/lingual surfaces of human molars. The cavities were measured in three dimensions by a TRIOS scanner and then filled with various resins (room temperature Z350 flowable resin and room temperature and 60 ℃ Z350 universal resin). Microleakage and gap formation at 2 sites were evaluated by stereomicroscopy and scanning electron microscope. Resin samples were prepared, and the top surface Vickers hardness (VHN) of all samples was measured at 1 day and 30 days postirradiation.
Results: No difference were observed in the 3D scans for the cavities sizes among groups with the same width. For the 1 mm-wide cavity, the lowest microleakage was obtained with the flowable group; for the 1.6 mm-wide cavity, the nonpreheating universal group showed the highest microleakage at site 1, and the preheating group exhibited lower microleakage than that of the nonpreheating universal group at site 2; and for the 2 mm-wide cavity, the preheating group presented lower microleakage at site 2. The gap formations were consistent with the microleakage degrees. The preheating group exhibited the highest VHN at 1 day and 30 days postirradiation.
Significance: A digital intraoral scanner could be used to scan the cavities in three dimensions. Preheating technology could reduce the microleakage of Z350 universal resin and enhance its surface hardness.
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http://dx.doi.org/10.1016/j.dental.2023.03.006 | DOI Listing |
Purpose: To make micro-CT comparison and evaluation of sealant penetration depth in different types of fissures after heating of the material or application of vibrations.
Materials And Methods: One hundred sound third molars have been sealed as follows: group 1 (n = 20), light-cured resin sealant at room temperature, group 2 (n = 20), light-cured resin sealant, preheated to 41.0°C, group 3 (n = 20), light-cured resin sealant, preheated to 51.
Int J Biol Macromol
January 2025
College of Food Science and Technology, Shanghai Ocean University, No. 999 Hucheng Huan Road, LinGang New City, Shanghai 201306, China; Engineering Research Center of Food Thermal-Processing Technology, Shanghai Ocean University, Shanghai 201306, China. Electronic address:
This study investigated the effects of pigskin gelatin hydrolysates (PGH, 4 %) as a cryoprotectant on the formation of advanced glycation end-products (AGEs) in pre-heated pork subjected to freeze-thaw cycles and subsequent reheating. During the freeze-thaw process, PGH significantly mitigated the increase in α-dicarbonyl precursors (α-DPs) and AGEs compared to the control group. Specifically, the levels of glyoxal and methylglyoxal decreased by 4.
View Article and Find Full Text PDFJ Conserv Dent Endod
November 2024
Department of Conservative Dentistry and Endodontics, Dayananda Sagar College of Dental Sciences, Bengaluru, Karnataka, India.
Context: One of the undesirable characteristics of dental composite resin is the polymerization shrinkage and the associated microleakage. The snowplow technique of placement and the preheating of the composite resins are methods to minimize microleakage.
Aim: The aim of this study was to comparatively evaluate microleakage in Class II cavities restored with snowplow technique using either preheated packable or flowable bulk-fill composite resin.
Materials (Basel)
December 2024
Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Technicka 5, 168 28 Prague 6, Czech Republic.
Due to limited slip systems activated at room temperature, the plastic deformation of Mg and its alloys without any preheating of initial billets is significantly limited. To overcome those issues, new methods of severe plastic deformation are discovered and developed. One such example is extrusion with an oscillating die, called KoBo.
View Article and Find Full Text PDFCureus
November 2024
Department of Endodontic and Operative Dentistry, Damascus University, Damascus, SYR.
Objectives This study aimed to compare the shear bond strength of three resin cements (light-cured resin cement, pre-heated composite resin, and dual-cured self-adhesive resin cement) when bonding to lithium disilicate discs. Materials and methods Thirty-six discs made of lithium disilicate were fabricated and etched with 9.5% (HF), and 36 human premolars were collected and immersed in the acrylic molds, then randomly divided into three equal groups (n = 12): Group 1: light-cured resin cement, Group 2: pre-heated resin composite, and Group 3: dual-cured resin cement.
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