Resin cement integrated with zein-incorporated magnesium oxide nanoparticles has previously been found to inhibit oral microbes and decrease bacterial biofilm. However, the bond strength and surface features of this biomaterial have yet to be investigated. The objective of this study was to evaluate the shear bond strength, mode of fracture, and surface roughness of resin cement modified with zein-incorporated magnesium oxide nanoparticles. Characterization of the cement was performed by X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. 126 human teeth were divided into 3 groups and cemented to lithium disilicate ceramic using resin cement with zein-incorporated magnesium oxide nanoparticles at concentrations of 0%, 1%, and 2% (n = 42). 21 samples of each group were subjected to the shear bond strength test, while the other 21 underwent thermocycling for 10,000 cycles before the test, after which all samples were evaluated for the mode of fracture. To assess surface roughness, resin cement disks were analyzed by a profilometer before and after undergoing thermocycling for 10,000 cycles. The shear bond strength of the cement with 1% and 2% nanoparticles was significantly higher than the control before thermocycling. The mode of fracture was found to be mainly adhesive with all groups, with the unmodified cement presenting the highest cohesive failure. There was no significant difference in surface roughness between the groups before or after thermocycling. The addition of zein-incorporated magnesium oxide nanoparticles to resin cement improved or maintained the shear bond strength and surface roughness of the resin cement.

(1) Background: Cementation of glass fiber posts to root canals has been associated with various failures, especially debonding. This narrative review aims to present the contemporary concepts concerning the adhesive cementation of glass fiber post and to discuss the optimal management of these factors. (2) Methods: Electronic search was performed in MEDLINE/Pub Med and Google Scholar using selected keywords examining the parameters post length, surface treatment of glass fiber posts, post space preparation and dentin pretreatment, resin cement selection, adhesive systems and hybrid layer formation, and clinical techniques. (3) Results: The search led to the selection of 44 articles. Epoxy resin-based endodontic sealers are recommended and the use of temporary cement in the root canal should be avoided. The minimum length of a glass fiber post adhesively cemented to a root canal is 5 mm. Irrigating the root canals with chlorhexidine, MTAD, or EDTA (alone or in combination with NaOCl) after post space preparation seems to enhance the bond strength. Silane application on the surface of the post seems to be beneficial. Concerning resin cements and adhesive systems, the results were rather inconclusive. Finally, resin cement should be applied inside the root canal with an elongation tip and photoactivation should be delayed. (4) Conclusions: Contemporary concepts of adhesive cementation of glass fiber posts can indeed improve the bond between glass fiber posts, resin cement, and root canal dentin, however, evidence coming from long-term randomized prospective clinical trials is needed in order to obtain safer conclusions.

Ceramic based on zirconium dioxide (ZD) is a modern, durable material for the manufacture of dentures. It is known that ZD is not etched as glass-ceramic, making it difficult to prepare this material before fixing.
OBJECTIVE: To study the impact of various methods of surface treatment of ZD-based ceramic on adhesive strength.
METHODS: Sandblasting with Al2O3 particles sized 50 μm and application of primers with 10-MDP phosphate monomer were used. Adhesive strength values for following 4 groups of samples were obtained: 1st group - RelyX U200 + sandblasting + Compofix new primer (n=9); 2nd group - Compofix + sandblasting + Compofix new primer (n=9); 3rd group - Panavia F 2.0 + sandblasting (n=9); 4th group (control) - Variolink Esthetic DC + sandblasting + Monobond Plus primer (n=9).
RESULTS: The highest strength of adhesion was in the 4th group - 48.71±5.71MPa, the smallest in the 3rd group - 9.49±35.24 MPa. Fully domestic components used in the 2nd group allowed to obtain values of 42.50±9.79 MPa. Adhesive strength in the 1st group was 34.11±4.78 MPa.
CONCLUSIONS: The absence of the 10-MDP-based primers application in the preparation of ZD ceramic reduces the adhesive strength between resin cement and its surface. The domestic set for fixation of dentures can be effectively used for ZD on the same basis as European analogue.
Керамика на основе диоксида циркония (ДЦ) является современным, прочным материалом для изготовления зубных протезов. Известно, что ДЦ не поддается травлению как стеклокерамика, что создает трудности для его подготовки перед фиксацией.
UNASSIGNED: Изучить влияние различных методов подготовки поверхности ДЦ керамики на прочность адгезии.
UNASSIGNED: Использовалась пескоструйная обработка Al2O3 с размером частиц 50 мкм и нанесение праймеров на основе фосфатного мономера 10-MDP. Получены значения прочности адгезии для 4 групп образцов: 1-я группа — RelyX U200 + пескоструйная обработка + новый праймер Компофикс (n=9); 2-я группа — Компофикс + пескоструйная обработка + новый праймер Компофикс (n=9); 3-я группа — Panavia F 2.0 + пескоструйная обработка (n=9); 4-я группа (контроль) — Variolink Esthetic DC + пескоструйная обработка + праймер Monobond Plus (n=9).
UNASSIGNED: Наиболее высокая адгезионная прочность была в 4-й группе — 48,71±5,71 МПа, наименьшая — в 3-й группе, равная 9,49±35,24 МПа. Полностью отечественные компоненты, использованные во 2-й группе, позволили получить значения 42,50±9,79 МПа. Прочность адгезии в 1-й группе — 34,11±4,78 МПа.
UNASSIGNED: Отсутствие применения праймеров на основе 10-MDP при подготовке ДЦ керамики снижает адгезионную прочность между полимерным цементом и ее поверхностью. Отечественный комплект для фиксации зубных протезов может быть эффективно использован для ДЦ наравне с европейским аналогом.

BACKGROUND: Commercially available resin cements consist of various filler sizes, filler content and monomers, and it is unclear which of these factors have the greatest effect on the color stability of laminate veneers.
OBJECTIVE: To evaluate the color stability of lithium disilicate-reinforced laminate veneers inserted with three commercial resin cements with various filler sizes/contents and monomers upon accelerated aging.
METHODS: Veneers were fabricated and cemented on resin abutments using three commercially available resin cements comprised of two different monomers and varying filler sizes/contents: 1) triethylene glycol dimethacrylate, TEGDMA (RelyX™ Veneer = 0.6 µm/66 %, Calibra® Esthetic Light Cure =1.2 µm/65 %); and 2) urethane dimethacrylate, UDMA (Variolink Esthetic LC = 0.1 µm/38 %). A total of 60 specimens were fabricated (n = 20 for each cement). The relative number of particles (N) and relative surface area (A) were calculated for each filler size/content. Color coordinates (L*, a*, b*) were measured, and color change (ΔE00) was calculated after cementation and following aging at 150, 300, 450, and 600 h using xenon light. Differences in color coordinates and color change were determined using repeated measures ANOVA followed by Tukey\'s post hoc test (α = .05). A post-hoc power analysis was performed to confirm reliability of the results.
RESULTS: Based on a post-hoc power analysis of a repeated measures ANOVA with two between-factors and 1 within-factor, we had 89 % power to detect a difference of effect by cement type, 10 % power to detect a difference by shade, and 100 % power to detect a difference of effect by aging. The UDMA-based cement (0.1 µm/38 %) was least affected by aging, despite having the largest number of particles (N = 1010) and largest particle surface area (A = 7.02). The TEGDMA-based cements exhibited a significant color change, with 0.6 µm/66 % (A = 2.03, N = 8.12) producing a larger ΔE00 than 1.2 µm/65 % (A = 1.00, N = 1.00).
CONCLUSIONS: Among the commercial cements tested, UDMA-based resin (0.1 µm/38 %) provided better color stability than TEGDMA-based resin cements. The color change after aging was affected by the relative surface area and relative number of particles for the TEGDMA-based resin cement (0.6 µm/66 % and 1.2 µm/65 %), with a larger surface area and a higher relative number of particles, accelerated color change with aging. The present study demonstrates a novel approach to determine color stability for any resin cement with particulate filler.
CONCLUSIONS: The dental practitioner should be selective in choosing a commercial light cure cementation product for laminate veneers, as UDMA containing resin cement is more resistant to color changes over time than TEGDMA, regardless of the filler size/content.

The purpose of the present study was to perform a preliminary analysis of the fitting of different fiber-reinforced composite (GFRC) posts to tooth root canals and determine the resin cement layer thickness. The following GFRC posts were assessed: bundle posts (Rebilda GTTM, VOCO, Germany), sleeve system (SAPTM, Angelus Ind, Brazil), and accessory posts (ReforpinTM, Angelus, Brazil). Twenty-four freshly extracted mandibular single-rooted pre-molars were endodontically treated and divided into six groups, according to the type of GFRC post and resin cement (self-adhesive or conventional dual-cured). Then, specimens were cross-sectioned and inspected by optical microscopy regarding the cement layer thickness and presence of defects such as pores, voids, or fissures were assessed. Bundle and accessory posts revealed a regular distribution of resin cement with a lower number of voids than found with sleeve systems. The sleeve system posts showed poor fitting at the apical portion of the root canals. The type of resin cement did not affect the thickness of the interface, although both bundle and accessory posts allow a better distribution of resin cement and fibers. The present preliminary study reveals interesting insights on the fitting of bundle and accessory posts to root dentin and resin cement layer thickness in oval-shape root canals. The sleeve system posts showed adequate fitting only at the coronal portion of the canals.

OBJECTIVE: This study aimed to evaluate the effect of ultrasonic activation of etch-and-rinse and self-etch adhesive systems on the bond strength of resin cement to irradiated root dentin.
METHODS: Eighty human maxillary anterior teeth were distributed into 8 groups (n = 10), according to the type of adhesive system used (etch-and-rinse and self-etch), the ultrasonic activation of the adhesive systems, and the dentin condition (irradiated or non-irradiated - 70 Gy). Endodontic treatment was performed followed by fiberglass post-space preparation. After fiberglass posts\' luting, the roots were transversely sectioned on dentin discs and submitted to the push-out bond strength test (0.5 mm/min). The fractured specimens were analyzed under a stereomicroscope and Scanning Electron Microscope (SEM) for failure mode classification. One of the dentin discs was analyzed under SEM to evaluate the characteristics of the adhesive interface.
RESULTS: Irradiated specimens had lower bond strength than non-irradiated specimens (P < 0.0001). Ultrasonic activation of both adhesive systems increased the bond strength of the resin cement to irradiated dentin (P < 0.0001). Radiotherapy significantly affected the failure mode in the middle (P = 0.024) and apical thirds (P = 0.032) (adhesive failure).
CONCLUSIONS: Non-irradiated specimens had a more homogeneous adhesive interface. When ultrasonically activated, both adhesive systems showed a greater number of resinous tags, regardless of the dentin condition.
CONCLUSIONS: Ultrasonic activation of adhesive systems is a feasible strategy to enhance fiberglass posts retention in oncological patients.

OBJECTIVE: To investigate a near-infrared-to-blue luminescence upconversion curing method for polymerizing resin cements under zirconia discs.
METHODS: Lava zirconia discs of different thicknesses (0.5-2.0 mm) were manufactured. First, the transmittances of the NIR and two blue lights (BLs) (LED and halogen lights) through these discs were measured. Second, NaYF4:Yb3+/Tm3+ upconversion phosphor (UP) powder was milled into 0.5-μm particle sizes. A light-curable resin cement VariolinkII base was chosen as the control (UP0), and an experimental cement (UP5) was prepared by adding 5 % UPs. These two cements were examined using multiphoton excitation microscopy for particle distribution. UP5 and UP0 were polymerized with or without zirconia shielding then subjected to a microhardness test. A multifold analysis was performed to examine the effects of zirconia thickness, curing protocols (pure BL or combined BL and NIR curing), and cement type.
RESULTS: The transmittance of NIR was superior to that of BL through zirconia discs of all thicknesses. UP particles were homogeneously distributed in UP5 and emitted blue luminescence under 980-nm NIR excitation. UP5 showed higher microhardness values than UP0 under any curing protocol or zirconia shielding condition. The combination of 20-s BL and 40-s NIR curing yielded the highest microhardness in uncovered UP5. However, combining 40-s BL and 20-s NIR curing surpassed the other groups when the zirconia discs were thicker than 0.5 mm.
CONCLUSIONS: NIR exhibits higher transmission through zirconia than BL. UP particles work as strengthen fillers and photosensitizers in cements. NIR upconversion curing could be a new strategy for polymerizing resin cements under thick zirconia restorations.

[This corrects the article DOI: 10.3389/fbioe.2024.1354241.].

OBJECTIVE: To evaluate the ability of the water glass treatment to penetrate zirconia and improve the bond strength of resin cement.
METHODS: Water glass was applied to zirconia specimens, which were then sintered. The specimens were divided into water-glass-treated and untreated zirconia (control) groups. The surface properties of the water-glass-treated specimens were evaluated using surface roughness and electron probe micro-analyser (EPMA) analysis. A resin cement was used to evaluate the tensile bond strength, with2 and without a silane-containing primer. After 24 h in water storage at 37 °C and thermal cycling, the bond strengths were statistically evaluated with t-test, and the fracture surfaces were observed using SEM.
RESULTS: The water glass treatment slightly increased the surface roughness of the zirconia specimens, and the EPMA analysis detected the water glass penetration to be 50 μm below the zirconia surface. The application of primer improved the tensile bond strength in all groups. After 24 h, the water-glass-treated zirconia exhibited a tensile strength of 24.8 ± 5.5 MPa, which was significantly higher than that of the control zirconia (17.6 ± 3.5 MPa) (p < 0.05). After thermal cycling, the water-glass-treated zirconia showed significantly higher tensile strength than the control zirconia. The fracture surface morphology was mainly an adhesive pattern, whereas resin cement residue was occasionally detected on the water-glass-treated zirconia surfaces.
CONCLUSIONS: The water glass treatment resulted in the formation of a stable silica phase on the zirconia surface. This process enabled silane coupling to the zirconia and improved the adhesion of the resin cement.

This study investigates the effects of dentin\'s drying time, roughness, and curing modes of resin cement on bond strength. Forty human teeth were divided into eight groups based on three experimental factors: dentin\'s roughness by 240-or 600-grit SiC paper (coarse or fine), dentin wetness with air-drying time (5-s or 10-s), and Single Bond Universal adhesive\'s curing mode by co-curing with RelyX Ultimate cement or light-curing separately (co-curing or light-curing). The micro-tensile bond strength of fifteen resin-dentin stikcs per groups was measured. Failure mode and adhesive layers were observed using stereoscopic and confocal laser scanning microscopy, respectively. The curing mode of the adhesive layer affected the bond strength of the dentin-resin cement (p<0.05). In particular, the light-curing mode exhibited a significantly higher bond strength than the co-curing one (p<0.05). The bond strength between the resin cement and dentin was improved in the 5-s drying groups than in the 10-s drying groups.