Dental materials journal最新文献

In this innovative study, the ferrule design for endocrowns was compared with a new preparation design with tetra-corner retention grooves at each corner of the access cavity, and the 3D finite element method was used for analysis. Resin nanoceramic (RNC), lithium disilicate glass-ceramic (LDS), polyetheretherketone (PEEK), and polymer-infiltrated ceramic network (PICN) materials were investigated. The new design significantly reduced the stress for LDS and PICN in axial and oblique loadings. On remaining tooth tissues, the tetra-corner retention groove design increased the stress peak for RNC and PEEK compared to the ferrule, while it decreased the stress for LDS and PICN under both forces. It was concluded that the new, modified preparation design could be used as an alternative design to the ferrule.

This study examined the effects of ultra-long hydroxyapatite nanofibers on bisphenol A-glycidyl methacrylate (Bis-GMA)/ urethane dimethacrylate (TEGDMA) dental resin. Experimental composites incorporating 2 wt% to 8 wt% ultra-long hydroxyapatite nanofibers were assessed for their mechanical properties, ion release behavior, and cytotoxicity. The results indicated that the addition of 2 wt% or 4 wt% nanofibers significantly enhanced the mechanical attributes of the composite materials, whereas higher concentrations led to a deterioration in performance. Moreover, these materials demonstrated the release of Ca²⁺ and PO₄^3- ions in both artificial saliva and lactic acid solutions, evidencing satisfactory cytocompatibility. The acquired data were subjected to statistical analysis via analysis of variance (ANOVA), with differences deemed statistically significant at p<0.05. Therefore, ultra-long hydroxyapatite nanofiber composites emerge as a promising innovative option for dental restoration.

Light-cured shade-characterizing agents are used for composite materials to mimic natural tooth color. Tooth-brushing abrasion tests were conducted to investigate the durability of the agents. Computer-aided design/computer-aided manufacturing (CAD-CAM) composite-resin blocks were used, and the surface was polished with #2000 SiC paper before the agent application. Four different shade agents were applied to the blocks, treated the surface no/with sandblasting. Tooth-brush abrasion tests were carried out for 20,000 cycles at a frequency of 2 Hz with 2.0 N of brushing force. Surface roughness, gloss, contact angle, and color differences were obtained. The number of repetitions was set to ten. It was found that a significant increase in surface roughness and decreases in gloss and water contact angle by tooth brushing tests were clarified. However, the color change by brushing was not significantly large. The color difference before and after applying agents and surface roughness differed in the shade differences in the agents.

Elucidate the dicalcium phosphate dihydrate (DCPD)-coated-beta-tricalcium phosphate (β-TCP) porous granules osteoinductivity performance in adipose-derived mesenchymal stem cells (ADMSCs). β-TCP porous was made by adding the sodium chloride (NaCl) powders with the dry powder of DCPD and CaCO₃ in the concentrations 40:60 (by wt%). Then, DCPD layer will be formed on porous β-TCP granules by immersing the granules in an acidic calcium phosphate solution. ADMSCs cultured was used to examine the biocompability of 300-600 µm and 600-1,000 µm DCPD-coated-porous β-TCP by means of microculture tetrazolium technique (MTT assay) and scratch assay. Bone morphogenic protein-2 (BMP-2), Osterix, Runt-related transcription factor-2 (Runx2), Alkaline phosphatase (ALP), Osteopontin, Osteonectin expression were investigated. The DCPD-coated porous β-TCP granules were culture together with ADMSCs is biocompatible. BMP-2, Runx2, Osterix, ALP, Osteopontin, Osteonectin expression in ADMSCs after culture together with DCPD-coated-β-TCP significantly enhanced. DCPD-coated-porous-β-TCP granules have good biocompatibility and high osteoconductivity in ADMSCs.

Low-wear resistance is a considerable problem with titanium. Despite the excellent wear resistance of Ti-Fe alloys, they exhibit brittleness, complicating their bulk usage. We developed a surface modification method for Ti involving the solid-phase diffusion of iron onto its surface. We coated iron onto the titanium surface and applied heat to successfully form a Ti-Fe alloy layer only on the outermost surface of titanium. The alloy layer exhibited a gradient structure characterized by a continuous decrease in iron concentration from the surface inward, without forming a distinct interface with the base material. Under various heat treatment conditions, the outermost alloy phase of the diffusion layer, in the β phase, resulted in surfaces with exceptional wear resistance. The improved wear resistance can be attributed to the potential surface structure of the Ti-Fe alloy, which combines hardness and ductility. This titanium-integrated structure, resulting from the gradient composition, reduces the likelihood of delamination.

To know about whether a bone substitute material octacalcium phosphate (OCP) is associated with bone formation by acting on surrounding tissue-derived cells, such as muscle cells, the effect of OCP was investigated on muscle-derived myoblast C2C12 cells in vitro. C2C12 cells were cultured with or without OCP granules. The diameter of the myotube formed from C2C12 cells with OCP was larger than that without OCP. mRNA expressions of myoblast differentiation markers (MyHC, MCK) and myokine (FGF-2) were increased by OCP, while Fndc5 and osteoglycin (myokine) were decreased. The alkaline phosphatase activity of mesenchymal stem cells was increased by adding the extract of media cultured with C2C12 cells and OCP up to 14 days. The chemical and spectroscopic analyses indicated that OCP hydrolysis progressed towards Ca-deficient hydroxyapatite in the media. The results suggest that OCP promotes myoblast differentiation and assists osteoblast differentiation through the myokines secretion under the environment induced by OCP hydrolysis.

This study was designed to investigate the effect of biodegradable octacalcium phosphate (OCP) bone substitute on osteoclast formation under the higher inorganic phosphorus concentration in vitro. We developed the gelatin particles releasing inorganic phosphate (Pi) ions as a model to change the local Pi ion concentration around OCP in the OCP/gelatin composite materials. Spectroscopic and chemical analyses indicated that Pi ion released around 2 mmol/L from gelatin particles promoted OCP hydrolysis, although excessive Pi ion release up to around 3 mmol/L suppressed the hydrolysis. The formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells was increased by the OCP hydrolysis promotion via modulately higher Pi release Pi ion release. However, OCP hydrolysis suppression by excessive Pi ion release decreased the formation of TRAP-positive cells. The present study suggests that the chemical environment induced by OCP hydrolysis under a suitable Pi ion concentration could be associated with promoting osteoclast formation.

Invisible orthodontics benefits significantly from aligner technology, yet optimizing material properties and thickness for diverse patient needs is a challenge. The aim of this study was to investigate the interaction between key material properties and thickness-and their collective influence on orthodontic treatment outcomes. A three-dimensional model of the tooth, periodontal ligament, and bone complex was constructed, with attachments centered on each tooth crown. Nine aligners, varying in thickness from 0.20 to 1.00 mm with material properties (Young's modulus (E) from 0.01 to 3.50 GPa and Poisson's ratio (ν) at 0.30), were analyzed. The study measured force and moment changes due to a 0.15 mm mesial-distal movement of the lateral incisor, validated by other teeth. Results show aligner thickness and E significantly affect force and moment, with increases promoting translational rather than tipping movements. These findings underscore precise aligner design's role in enhancing orthodontic outcomes.

Commercial toothpaste contains 1,500 ppm NaF to prevent caries; however, the effect of NaF on tooth restorative materials is not fully understood. This study investigated the impact of a 1,500 ppm NaF solution at different pH levels on the mechanical and physicochemical properties of CAD-CAM materials. Aqueous 1,500 ppm NaF solutions were prepared at pH levels 3, 5, and 7. Four CAD-CAM blocks -lithium disilicate glass, feldspathic porcelain, polymer-infiltrated ceramic network, and resin composite- were immersed in the solutions at 37°C for 10 days. Samples were evaluated for surface roughness, flexural modulus, strength, Vickers hardness, and water sorption/solubility. Results indicated that NaF solutions dissolved silica components, increasing surface roughness and water solubility and reducing hardness, especially at lower pH levels. Flexural properties remained mostly unchanged. These findings suggest that acidic NaF solutions more strongly degrade the surface properties of CAD-CAM materials.

Mineral trioxide aggregate (MTA) cement has excellent properties, such as biocompatibility and mineral induction ability for various dental procedures. To provide these favorable properties, MTA-based sealers, such as MTA Fillapex (MF), Bio-C Sealer (BC), NeoSEALER Flo (NSF), and NeoMTA 2 (NM2), have been developed and introduced into the market. Additionally, an endodontic sealer containing bioactive glass with mineral induction ability was introduced as the Canal Sealer BG (CS-BG). In this study, we evaluated the mineral induction and sealing ability of five bioceramic-based sealers. The results indicated that NSF, NM2, BC, and CS-BG had superior mineral induction capacities compared with MF. Although NSF, NM2, BC, and CS-BG exhibited comparable sealing performances, NSF had a statistically superior sealing capability compared to MF. According to these findings, bioceramic sealers other than MF containing resin components have excellent mineral induction capacity, making them effective for root canal sealing in clinical applications.