Volume 62, Issue 4

Abstract: Objective: This study aimed to investigate the effect of microabrasion, bleaching, and resin infiltration (RI) on the color and gloss of stained remineralized caries-like lesions (s-RCL). Materials and methods: Human enamel specimens were demineralized and then randomly assigned to seven groups (n = 12). G1; no treatment, G2; RI, G3; remineralized and stained to create s-RCLs, G4; s- RCLs + at-home bleaching protocol (AHB) (15% carbamide peroxide, 4 h/d × 7); G5; s-RCLs + microabrasion (6.6% hydrochloric acid, 1 min/3 cycles) + AHB; G6; s-RCLs + AHB + RI; G7: s-RCLs + microabrasion + AHB+ RI. Color and gloss were measured at baseline, after demineralization, and after the treatments. Outcomes were analyzed using ANOVA followed by Tukey’s test (α =0.05). Results: The mean color change after demineralization and staining (except in G1 and G2) was significant (p < 0.0001), indicating the creation of white spot lesions and s-RCLs, respectively. Treatment improved the color in G2, but not significantly. Groups 4–7 showed improvement (p < 0.01) yet did not exceed the staining values. Gloss decreased (p < 0.0001) after staining in all groups except in G1 and G2, compared to demineralization, with no significant difference among groups. Treatments significantly increased (p < 0.0001) gloss, except in the controls (G1 and G3), where G7 had the highest value and G4 had the lowest. Conclusion: The combination of microabrasion, AHB, and RI has demonstrated significant potential in improving the gloss and an average efficacy in partially improving the color outcome of s-RCL.

Abstract: The present study assesses the surface roughness (SR) and microhardness (Vickers Hardness Number, VHN) of novel resin-filled ceramic and resin composite materials fabricated using 3D printers and CAD/CAM technologies after being subjected to thermal cycling. Permanent resin restorations were fabricated using 3D printers (C; Saremco Print Crowntec, F; Permanent Crown Resin Formlabs, B VarseoSmile Crown Plus Bego) and resin-containing CAD/CAM permanent restorative materials (E; Vita Enamic, Vita, U; 3M Lava Ultimate), with a total of 75 rectangular specimens produced (12 × 14 × 1.5 mm) (n = 15). The SR (Ra, Rz) and MH values of the materials were measured before and after thermal aging, and scanning electron microscopy (SEM) images were obtained following thermal cycling. The dataset obtained from the study was evaluated with a Two-Way Analysis of Variance (Twoway ANOVA) (α = 0.05). There was a broad and statistically significant difference in the SR values of all groups before and after thermal ageing (p < 0.001). In the MH intergroup comparisons, the values of the groups before and after the ageing process were found to be statistically significant (p < 0.001). The highest Ra values were recorded in 3D printed resins, while the lowest values were observed in CAD/CAM-produced materials. Furthermore, the number of samples produced using 3D printers was lower than that produced by CAD/CAM.

Abstract: Background: Postoperative recurrence remains a major challenge in colorectal cancer due to residual tumor cells that survive surgical resection. Systemic chemotherapy is often insufficient for complete local control and causes systemic toxicity. Combining local chemotherapy with gene silencing may offer a more effective and targeted strategy. Methods: We developed PLGA-based nanoparticles co-loaded with irinotecan and Bcl-2-targeting siRNA. The nanoparticles were characterized for morphology, encapsulation efficiency, release kinetics, cellular uptake, cytotoxicity, gene silencing efficiency, and in vivo efficacy using a murine tumor resection model. Results: The dual-loaded nanoparticles exhibited uniform spherical morphology, high encapsulation efficiencies (82.3% for irinotecan and 69.5% for siRNA), and sustained release of both agents. Conclusion: This localized combinatorial delivery system provides a synergistic approach for eliminating residual tumor cells and preventing recurrence after colorectal cancer surgery, demonstrating high therapeutic potential and translational value.

Abstract: Objective: To evaluate the clinical efficacy of chitosan/alginate (CS/Alg) double-network hydrogels in the repair of temporomandibular joint (TMJ) disc defects and to investigate the underlying mechanisms. Methods: A prospective randomized controlled trial was conducted, including 104 patients with irreducible anterior disc displacement or disc perforation of the TMJ who were treated at the Department of Oral and Maxillofacial Surgery between January 2023 and December 2023. Patients were randomly divided into an experimental group (CS/Alg double-network hydrogel implantation, n = 53) and a control group (conventional disc repair or discectomy, n = 51). Randomization was performed using computer-generated random number tables with allocation concealment. Primary outcome measures included maximum interincisal opening (MIO), pain visual analog scale (VAS) scores, and TMJ functional index. Secondary outcome measures included imaging findings, complication rates, and patient satisfaction. Follow-up evaluations were conducted at baseline, 1 months, 3 months, 6 months, and 12 months postoperatively. Results: A total of 96 patients completed the 12-month follow-up (experimental group: 50 patients; control group: 46 patients). No significant differences were observed in baseline characteristics between the two groups (p > 0.05). At 12 months postoperatively, the experimental group demonstrated significantly greater improvement in MIO compared to the control group (13.8± 4.6 mm vs. 7.9 ± 4.3 mm, p < 0.001). The reduction in VAS pain scores was superior in the experimental group compared to the control group (5.4 ± 1.3 vs. 3.8 ± 1.6, p < 0.001). The experimental group achieved higher TMJ functional index scores (82.4 ± 11.2 vs. 71.3 ± 13.6, p < 0.001) and higher treatment success rates (94.0% vs. 78.3%, p = 0.021). Imaging evaluation revealed better preservation of disc position and joint space in the experimental group (p < 0.05). The overall complication rate was significantly lower in the experimental group compared to the control group (20.8% vs. 62.7%, p < 0.001). Multivariable analysis identified CS/Alg double-network hydrogel treatment as an independent protective factor for treatment success (OR = 3.58, 95% CI: 1.42–9.03, p = 0.007). Histological analysis demonstrated good biocompatibility and fibrocartilaginous tissue regeneration. Conclusion: CS/Alg double-network hydrogels exhibit excellent clinical efficacy and safety in TMJ disc repair. Through multiple mechanisms, including providing appropriate mechanical support, modulating the immune microenvironment, and promoting extracellular matrix remodeling, this material significantly improves joint function and patient quality of life, offering a novel and effective therapeutic strategy for TMJ disorders.

Abstract: Fused deposition modeling (FDM) is increasingly used to manufacture functional polymer components, but the mechanical performance of printed parts is strongly influenced by process parameters. This study examines the effects of build orientation, infill density, infill pattern, and printing speed on the tensile behavior of polylactic acid (PLA) specimens. Dog-bone samples with ISO 527-2 type 1A geometry were printed using three build orientations (A—horizontal, B—vertical, C—lateral), two infill densities (40% and 70%), two infill patterns (triangle and tri-hexagon), and two printing speeds (40 and 60 mm/s). Tensile tests were performed to determine Young’s modulus, yield stress, ultimate tensile strength, and elongation at break. The lateral (C) orientation provided the highest mechanical performance, with an average ultimate tensile strength of 47 MPa and a Young’s modulus of 2.9 GPa, compared to 33 MPa (E ≈ 2.4 GPa) for the horizontal (A) orientation and 16 MPa (E ≈ 2.0 GPa) for the vertical (B) orientation. For horizontally printed specimens, a 70% infill consistently increased tensile strength relative to 40% infill. The combination of 70% infill, triangular pattern, and 40 mm/s printing speed (A70T40) achieved the highest ultimate tensile strength among the infill configurations. These findings highlight the importance of selecting appropriate printing parameters when PLA components are intended for load-bearing applications.

Abstract: Background: Postoperative recurrence of glioblastoma is driven by residual tumor cells at the resection margins. Conventional systemic chemotherapy is limited by poor brain penetration and systemic toxicity. Methods: We developed an injectable thermoresponsive hydrogel for localized delivery of cisplatin. The hydrogel undergoes sol–gel transition at body temperature, forming an in situ drug depot. Physicochemical properties, in vitro release, cytotoxicity, and cellular platinum uptake were evaluated. Results: The hydrogel exhibited a porous structure and a sharp gelation near 37◦C. Drug release was temperature-dependent, with sustained release at physiological temperature. Cisplatin (CDDP)-loaded hydrogel significantly reduced glioma cell viability and achieved higher intracellular platinum accumulation compared to free drug. Conclusion: This thermoresponsive hydrogel enables injectable, localized cisplatin delivery with improved cellular uptake and cytotoxicity, offering a promising platform for preventing glioblastoma recurrence after surgery.

Abstract: Background: Airway epithelial injury is common in respiratory diseases and post-surgical conditions, leading to impaired barrier function and delayed healing. There remains an urgent need for localized biomaterial-based therapies to support epithelial repair under oxidative stress. Methods: We developed a self-healing injectable hydrogel based on chitosan and oxidized dextran, crosslinked via dynamic imine bonds. N-acetylcysteine (NAC) was encapsulated as a therapeutic payload. The hydrogel was characterized for rheological recovery, drug release kinetics, and evaluated in vitro using airway epithelial cells. Results: The hydrogel exhibited excellent self-healing behavior and sustained NAC release over 48 h. It promoted cell proliferation, enhanced migration in scratch assays, and upregulated ZO-1 expression. In an H₂O₂-induced injury model, NAC-loaded hydrogels significantly restored cell viability to near-normal levels. Conclusion: This NAC-loaded self-healing hydrogel provides both mechanical and biochemical support for airway epithelial repair. It offers a minimally invasive platform for localized treatment of airway injuries, with potential applications in respiratory disease management and post-operative mucosal healing.