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Objectives: This study aimed to evaluate the influence of different polymerisation methods of acrylic resin for ocular prostheses on the subcutaneous tissue inflammatory response of rats., Methods: The study was conducted at the Basic Sciences Department, Araçatuba Dental School, São Paulo State University (UNESP), Brazil, from 2016 to 2018. The samples were prepared by water bath (WB), microwave energy (MW) or autopolymerisation (AP) (n = 20 samples per group). The inflammatory response (cell count and immunohistochemical analysis of interleukin [IL]-1β, IL-6, tumour necrosis factor [TNF]-α, IL-17 and macrophage inflammatory protein-3α) was analysed by the implantation of a sample from each group in the subcutaneous tissue of 20 Wistar rats and evaluated after seven, 15, 30 and 60 days. The quantitative and qualitative data were analysed using analysis of variance and Tukey tests ( P <0.05) and visual comparison, respectively., Results: There was a moderate inflammatory infiltrate for the MW and AP groups and a light infiltrate for the WB group after seven days. The inflammatory infiltrate and the immunolabeling of tested targets decreased gradually during the 60-day period. The AP group had the highest immunolabeling of TNF-α (seven days), IL-1β and IL-17 (at 15 and 30 days) and IL-6 (at 30 and 60 days). The WB and MW groups showed greater immunolabeling at 15 and 30 days, while the MW group also had high results at 60 days., Conclusion: Polymerisation by microwave energy and by chemical activation resulted in a higher inflammatory response., Competing Interests: CONFLICT OF INTEREST The authors declare no conflicts of interest., (© Copyright 2022, Sultan Qaboos University Medical Journal, All Rights Reserved.)

The study evaluated the influence of cycles and methods of an ocular prosthesis resin on cytotoxicity toward human conjunctival cells. Resins were polymerized by water bath (WB, 74 °C or 100 °C for 30 min to 9 h), microwave (MW, 1200 W, 3 to 14 min and 30 s at 0 to 720 W), or autopolymerization (AP, room temperature for 20 min ± 60 °C for 30 min). Degree of conversion (DC), cytotoxicity, level of inflammatory mediators, gene expression of different markers, and apoptosis were evaluated. Data were submitted to ANOVA and Tukey test (p < 0.05). WB with longer processing time at higher temperature had highest DC (85.6%) and higher TGF β1-gene expression (1.39); long cycle low power MW showed lowest DC (69.6%), lower cell proliferation (85.4%, MTT), and large IL-2 release (39,297 ng/mL). AP with additional processing time showed lower cell proliferation (75.3%, Alamar Blue), and AP polymerized at room temperature showed higher CASP 9-gene expression (1.21). AP methods showed higher IL-6 release (>277 pg/mL). Short cycle medium power MW had higher IL-23 release (534.2 pg/mL). MW (long and short cycles) and AP polymerizations have triggered a more intense inflammatory response. Among methods recommended by the manufacturer, WB showed high DC and less cytotoxicity., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: This study was undertaken to analyze if different preparation and exposure periods of eluates from ocular prosthesis acrylic resin influence the cytotoxicity for conjunctival cells., Methods: Twenty-four acrylic resin specimens were divided, according to the period of eluate exposure to Chang conjunctival cells (24 and 72 hours). Eluates were prepared in four different ways: 24, 48, and 72 hours of resin specimen immersion in medium and 24 hours of immersion in water, followed by 24 hours of immersion in medium. MTT assay was used to evaluate the cytotoxic effect. The production of IL-1β, IL-6, TNF-α, and chemokine macrophage inflammatory protein 1α was evaluated by ELISA, while the mRNA expression of type IV collagen (COL IV), transforming growth factor β (TGF-β), and matrix metalloproteinase 9 (MMP9) were evaluated by real-time RT-PCR technique. The statistical analysis was carried out using ANOVA with Bonferroni post-hoc test and the student’s t-test (p < 0.05)., Results: Significant quantities of IL-6 (4.594 pg/mL) and mRNA expression of COL IV (1.58) were verified at 72 hours of eluate exposure to cells, as compared to 24 hours. After the 72-hour exposure of eluates to cells, lower cell proliferation (88.4%) and higher IL-6 quantities (12.374 pg/mL), as well as mRNA expression of COL IV (2.21), TGF-β (2.02), and MMP9 (5.75) were observed, which corresponded to 72 hours of a specimen immersed in medium., Conclusion: Longer periods of eluate preparation and exposure from the acrylic resin to cells are related to higher production of proinflammatory cytokines and extracellular matrix proteins.