Browsing by Author "Atmeh, Amre"

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The Effect of Sealer Application Methods on Voids Volume after Aging of Three Calcium Silicate-Based Sealers: A Micro Computed Tomography Study
(2022-03) Atmeh, Amre
Abstract: During obturation, air voids are undesirable as they may provide shelter for microorganisms or passage for fluids. This study aimed to compare the occurrence of voids between three calcium silicate-based sealers (CSBSs) (MTA-Fillapex, BioRoot-RCS, Bio-C) and the change in their volume after aging. In addition, we aimed to compare voids when using two sealer application methods: lentulo-spiral (LS) and gutta-percha (GP) cone. Thirty extracted mandibular premolars (n = 30) were endodontically prepared and obturated using single GP cone (SGPC) technique. Each sealer was applied to 10 teeth (n = 10) using LS or GP. Micro-computed tomography (micro-CT) was used to quantify the volume of root filling and voids before and after 8-week storage in a phosphate-rich medium. The percentage of root filling and voids were compared between the groups using a Mann– Whitney U test and Kruskal–Wallis test with a Bonferroni correction. Before aging, the percentages of root filling volume after obturation were comparable with no significant differences between sealers (p = 0.325) or application methods (p = 0.950). After aging, the voids’ volume increased significantly in all sealers (p ≤ 0.05). However, no significant differences were found between sealers (p = 0.302). In conclusion, voids in CSBSs may not reduce in size with aging; hence, SGPC should be carefully selected for suitable cases.
Glass-ionomer and calcium silicate-based cements interactions with human dentine in health and disease: Two-photon fluorescence microscopy and Raman spectroscopy analysis.
(2022) Atmeh, Amre
Objectives: To investigate the potential mineralising effects of calcium silicate-based dentine replacement material (Biodentine™) in comparison with glass-ionomer cement (GIC) (Fuji IX™) on different human dentine substrates using a multimodal non-invasive optical assessment. Methods: Cements were applied on artificially demineralised or naturally carious dentine and stored for 4 weeks in phosphate-rich media +/- tetracycline used for mineralisation labelling. Interfacial dentine was examined from the same sample and location before and after aging using two-photon fluorescence microscopy, fluorescence lifetime imaging (FLIM) and second harmonic generation (SHG) imaging. Additionally, Raman spectroscopy was used to detect changes in the mineral content of dentine. Results: Significant changes in the fluorescence intensity and lifetime were detected in partially demineralised dentine and caries-affected dentine underneath both tested cements, after storage (p < 0.001). This was associated with a significant increase in the mineral content as indicated by the increased intensity of the phosphate Raman peak located at 959 cm−1 (p < 0.0001). Caries-infected dentine showed significant fluorescence changes under Biodentine™ after storage (p < 0.001), but not under GIC (p = 0.44).
Inflammatory and differentiation cellular response to calcium silicate cements: An in vitro study
(2023) Atmeh, Amre
Aim: Inflammatory-regenerative cell interaction is believed to mediate hard tissue formation. This study aimed to investigate the interaction between human inflammatory monocytes with human regenerative fibroblasts after exposure to different calcium silicate materials. Methodology: Human monocytes were cultured on three materials, polystyrene (PS), mineral trioxide aggregates (MTA) and biodentine (BD), in the presence or absence of lipopolysaccharide (LPS). Half of the monocyte-conditioned media (MoCM) of each group was used to analyse inflammatory cytokine secretion, namely TNF-α, IL-1β, IL-1RA and IL-6. The remaining MoCM was used to culture recipient fibroblasts, measuring the cell number (proliferation) and levels of alkaline phosphatase (differentiation) and lactic acid dehydrogenase (cytotoxicity). Results: In absence of LPS, MTA was associated with higher secretion of TNF-α and lower secretion of IL-1β, while BD triggered higher secretions of both cytokines when both materials were compared to control (PS). When LPS was added, higher levels of all analysed cytokines were observed in the PS and BD groups, whereas for the MTA group, only TNF-α and IL-6 were increased. Fibroblasts responded differently to the MoCM from the different groups, revealing significant increases in proliferation and differentiation capacities, particularly when cultured in CM from monocytes exposed to MTA. The morphological evaluation revealed different patterns of fibroblast shape and spread in the different MoCM groups. Conclusion: Calcium silicate materials modulate the monocyte inflammatory response, which subsequently induce differential effects on the recipient fibroblasts. MTA appears to promote the secretion of prodifferentiation signals from the monocytes, which are received by fibroblasts, promoting their proliferation and differentiation. The model represents a promising tool to evaluate the interaction of different cells in response to different materials.
Present status and future directions: Hydraulic materials for endodontic use
(2022) Atmeh, Amre
Background: Hydraulic materials are used in Endodontics due to their hydration characteristics namely the formation of calcium hydroxide when mixing with water and also because of their hydraulic properties. These materials are presented in vari-ous consistencies and delivery methods. They are composed primarily of tricalcium and dicalcium silicate, and also include a radiopacifier, additives and an aqueous or a non- aqueous vehicle. Only materials whose primary reaction is with water can be classified as hydraulic. Objectives: Review of the classification of hydraulic materials by Camilleri and the literature pertaining to specific uses of hydraulic cements in endodontics namely intra- coronal, intra- radicular and extra- radicular. Review of the literature on the ma-terial properties linked to specific uses providing the current status of these materials after which future trends and gaps in knowledge could be identified. Methods: The literature was reviewed using PUBMED, and for each clinical use, the in vitro properties such as physical, chemical, biological and antimicrobial character-istics and clinical data were extracted and evaluated. Results: A large number of publications were retrieved for each clinical use and these were grouped depending on the property type being investigated. Conclusions: The hydraulic cements have made a difference in clinical outcomes. The main shortcoming is the poor testing methodologies employed which provide very limited information and also inhibits adequate clinical translation. Furthermore, the clinical protocols need to be updated to enable the materials to be employed effectively.