El-Rashidy, A. A., and O. O. Shaalan, Assessment of the Effect of Finishing and Polishing and In-Office Bleaching on Surface Roughness of Commercially Available Resin Composites: An In-Vitro Study, , vol. 6, issue 1, pp. 66 - 74, 2024. AbstractWebsite

Aim: The aim of the current study was to evaluate the effect of finishing and polishing and an in-office bleaching gel on the surface roughness of single-shade (Omnichroma) and group-shade (Estelite Alpha) resin composites.Methodology: A total of ten composite disc-shaped specimens; five specimens for each material were prepared using Teflon mold (1-mm thick and 8-mm diameter). The resin composites were cured against mylar strips to produce flat smooth surface of the tested specimens. Then each disk was finished and polished using multi-step finishing and polishing system (Astropol, Ivoclar Vivadent). Each specimen was bleached using an in-office bleaching system two times in a row using 38% hydrogen peroxide (H2O2). The average surface roughness (Ra, in μm) of the specimens was measured using non-contact optical profilometry at baseline, after finishing and polishing, and after bleaching procedure. Intergroup comparison was performed using independent t-test, while intragroup comparison was performed using one-way ANOVA followed by Tukey post-hoc.Results: Comparison between both materials has revealed statistically significant difference at baseline (P = 0.0086), with Estelite Alpha showing higher surface roughness. However, after polishing and bleaching there was no statistically significant difference between both materials (P = 0.5796 and P = 0.3010) respectively. Conclusion: The surface roughness of resin composites is material dependent. Omnichroma demonstrated lower initial Ra value than Estelite Alpha. However, Omnichroma showed significant increase in surface roughness following finishing and polishing, unlike Estelite Alpha. Bleaching with 38% H2O2 showed no effect on the surface roughness of both materials.

Rady, D., S. El Moshy, M. M. S. Abbass, K. M. Sadek, A. A. El-Rashidy, I. A. Radwan, and K. M Fawzy El-Sayed, "Inflammatory Biomarkers in Periodontitis and Their Effect on the Stem/Progenitor Cells: Molecular Basis of Bone Resorption and Bone Regeneration", Handbook of Stem Cell Applications, Singapore, Springer Nature Singapore, pp. 1 - 37, 2023. Abstract

Periodontitis is considered one of the most chronic inflammatory diseases damaging the soft and hard tissues supporting the teeth. In periodontitis, three definite stages are distinguished; different biomarkers could detect infection, inflammation, and tissue destruction. One of the main considerations in a successful periodontal treatment is understanding the underlying mechanisms of alveolar bone loss and formation. Key cellular players include osteoclasts, osteoblasts, bone marrow stromal cells, and osteocytesin in addition to mesenchymal stem/progenitor cells (MSCs). This chapter highlights the significant effects of the different inflammatory stimuli in conjunction with periodontal diseases, influencing bone resorption and regeneration.

El-Rashidy, A. A., I. A. Radwan, D. Rady, S. El Moshy, M. M. S. Abbass, K. M. Sadek, A. E. El-Arab, and K. M. Fawzy El-Sayedb, "Dentale mesenchymale Stamm-/Progenitorzellen: Eine neue Perspektive für die Regenerative Medizin", Stammzellen: Neueste Fortschritte, Cham, Springer International Publishing, pp. 149 - 172, 2023. Abstract

Zahnmedizinische mesenchymale Stamm-/Progenitorzellen (MSCs) haben einzigartige biologische Eigenschaften in Bezug auf die Expression von Genen und Proteinen. Sie besitzen die gleichen Merkmale wie nicht-dentale MSCs, darunter die Fähigkeit zur Selbsterneuerung, das Potenzial zur Differenzierung in verschiedene Zelllinien und immunmodulatorische Eigenschaften. Darüber hinaus weisen sie im Vergleich zu MSCs aus anderen Körpergeweben ein höheres Regenerationspotenzial auf. Da sie leicht mit minimalinvasiven Verfahren gewonnen werden können, sind sie vielversprechende Ressourcen für Tissue Engineering und regenerative Therapien. Dieses Kapitel gibt einen kurzen Überblick über die verschiedenen Quellen dentaler Stamm-/Progenitorzellen, die spezifischen Eigenschaften dentaler MSCs und ihre Vorteile gegenüber nicht-dentalen MSCs. Darüber hinaus wird in diesem Kapitel das osteogene, hepatogene, neurogene, immunmodulatorische und zahngeweberegenerative Potenzial dieser Zellen beschrieben. Es wird ein Vergleich zwischen dentalen Stamm-/Progenitorzellen aus verschiedenen Quellen hinsichtlich ihres Proliferations- und Regenerationspotenzials diskutiert. Darüber hinaus werden in diesem Kapitel die von diesen Zellen exprimierten oder induzierten Wachstumsfaktoren und Zytokine sowie die Auswirkungen dieser Signalmoleküle auf die Vielfalt ihres Differenzierungs- und Regenerationspotenzials untersucht. Da die Aufrechterhaltung der genetischen Integrität gegen DNA-Schäden und andere Herausforderungen im Zusammenhang mit zellbasierten Therapien den Nutzen von zahnmedizinischen MSCs in der klinischen Anwendung behindern, werden in diesem Kapitel die wichtigsten Einschränkungen hinsichtlich ihrer klinischen Umsetzung aufgezeigt und mögliche Lösungen vorgeschlagen.

Shaalan, O., and A. El-Rashidy, "Color matching of single-shade composite compared to multi-shade composite after aging and bleaching: An In Vitro Study", Egyptian Dental Journal, vol. 69, issue 3, 2023.
El-Rashidy, A. A., O. Shaalan, R. M. Abdelraouf, and N. A. Habib, Effect of immersion and thermocycling in different beverages on the surface roughness of single- and multi-shade resin composites, , vol. 23, issue 1, pp. 367, 2023. AbstractWebsite

Resin composite restorations are highly esthetic restorations, which should have and maintain high surface polish. However, esthetic restorations are subjected to different beverages at variable temperatures, which may affect their surface roughness. This study aimed to evaluate the surface roughness of single-shade (Omnichroma) and multi-shade (Filtek Z350XT) composite materials, following aging by immersion and thermocycling in different beverages, simulating one year of clinical service.

Nabil Sulyiman, S., A. A. El-Rashidy, S. El Moshy, M. M. S. Abbas, and G. Waly, "Nano eggshell-based slurry as a direct pulp-capping material: In vitro characterization and histopathological assessment in an experimental animal model", International Endodontic JournalInternational Endodontic Journal, vol. 56, issue 9: John Wiley & Sons, Ltd, pp. 1129 - 1146, 2023. AbstractWebsite

Abstract Aim Pulp vitality is essential for tooth integrity. Following pulp exposure, choosing a suitable pulp-capping material is crucial to maintain pulp vitality. However, the reparative dentine bridge created by calcium hydroxide (Ca(OH)2) is generally porous and incomplete. The aim of the current study is to assess the in vitro and in vivo bioactivities of nano eggshell-based slurry (NES), using NES as a direct pulp-capping material, compared with Ca(OH)2 in rabbit animal model. Methodology Nano eggshell powder (NE) was characterized for particle morphology, chemical composition and ion release. In vitro bioactivity was tested by immersion in simulated body fluid (SBF) for 7?days. For histopathological evaluation, 36 adult New Zealand rabbits (72 pulp exposures) were divided into nine groups (n?=?8) according to the pulp-capping material (NES, Ca(OH)2 and no capping as negative control group) and the animals were sacrificed after 7, 14 or 28?days. The pulps of the two lower central incisors were exposed and then directly capped by Ca(OH)2 or NES or left untreated. The cavities were then sealed with glass ionomer cement. Teeth were collected for histopathological evaluation using an optical microscope. Pulp haemorrhage, inflammation, fibrosis and calcific bridge formation were assessed. Results were statistically analysed using anova and Tukey's tests. Results Nano eggshell particles were spherical with a 20?nm diameter and were composed mainly of calcite. Statistical analysis showed that there was a significant increase in the release of all investigated ions between days 1 and 28, except for copper. NES group showed a significantly higher release of all elements as compared to Ca(OH)2. Environmental scanning electron microscope micrographs of NES incubated for 7?days in SBF showed the formation of HAp with a Ca/P ratio (1.686). For histopathological evaluation, the difference between groups was statistically significant. At day 28, 75% of the pulps of the Ca(OH)2 group showed mild calcific bridge in comparison with 100% moderate calcific bridge in the NES group. The NES group showed significantly less inflammation at days 7 and 28, and higher fibrosis at day 7 compared with Ca(OH)2. Conclusions Nano eggshell-based slurry represents a promising novel direct pulp-capping material with favourable pulp tissue response.

Sadek, K. M., S. El Moshy, I. A. Radwan, D. Rady, M. M. S. Abbass, A. A. El-Rashidy, C. E. Dörfer, and K. M Fawzy El-Sayed, "Molecular Basis beyond Interrelated Bone Resorption/Regeneration in Periodontal Diseases: A Concise Review", International Journal of Molecular Sciences, vol. 24, issue 5, 2023. Abstract

Periodontitis is the sixth most common chronic inflammatory disease, destroying the tissues supporting the teeth. There are three distinct stages in periodontitis: infection, inflammation, and tissue destruction, where each stage has its own characteristics and hence its line of treatment. Illuminating the underlying mechanisms of alveolar bone loss is vital in the treatment of periodontitis to allow for subsequent reconstruction of the periodontium. Bone cells, including osteoclasts, osteoblasts, and bone marrow stromal cells, classically were thought to control bone destruction in periodontitis. Lately, osteocytes were found to assist in inflammation-related bone remodeling besides being able to initiate physiological bone remodeling. Furthermore, mesenchymal stem cells (MSCs) either transplanted or homed exhibit highly immunosuppressive properties, such as preventing monocytes/hematopoietic precursor differentiation and downregulating excessive release of inflammatory cytokines. In the early stages of bone regeneration, an acute inflammatory response is critical for the recruitment of MSCs, controlling their migration, and their differentiation. Later during bone remodeling, the interaction and balance between proinflammatory and anti-inflammatory cytokines could regulate MSC properties, resulting in either bone formation or bone resorption. This narrative review elaborates on the important interactions between inflammatory stimuli during periodontal diseases, bone cells, MSCs, and subsequent bone regeneration or bone resorption. Understanding these concepts will open up new possibilities for promoting bone regeneration and hindering bone loss caused by periodontal diseases.

Shaalan, O., and A. El-Rashidy, "Antibacterial Effect of Miswak herbal toothpaste Compared to Fluoride Toothpaste in High Caries Risk Patients: Randomized Clinical Trial.", Journal of clinical and experimental dentistry, vol. 15, issue 7, pp. e526-e534, 2023. Abstract

BACKGROUND: Modern toothbrushes origin can be traced to plant-derived chewing sticks, which were documented to be used Babylonians as early as 3500 BC. Chewing sticks are routinely used for cleaning teeth in Asia, Africa, South America, and the Middle East. The aim of the current study was to evaluate the antibacterial effect of miswak herbal toothpaste compared to fluoride toothpaste using a normal toothbrush, against Streptococcus mutans in high caries risk patients.

MATERIAL AND METHODS: A total of 32 participants were recruited to the current clinical trial using convenience sampling randomly either to miswak or fluoride toothpastes groups (n=16). The bacterial count represented as colony-forming units per milliliter (CFU/ml) was assessed at baseline and after 1 week, 1 month and 3 months. Moreover, the ion release for silicone, calcium, phosphorus, and fluoride from both toothpastes was analyzed in addition to the pH of both toothpastes and their supernatants. Intergroup comparison was performed using independent t test, while intragroup comparison was performed using repeated measures ANOVA followed by tukey post-hoc test and paired t test when appropriate.

RESULTS: There was no statistically significant difference between both toothpastes for the S. mutans count within each follow up period, however the bacterial count significantly decreased over time in both groups. Signal Fluoride toothpaste exhibited statistically significant higher ion release when compared to the Dabur Miswak toothpaste. There was no statistically significant difference between either toothpastes regarding pH ( = 0.5368), while comparison between supernatants of toothpastes have shown statistically significant difference ( = 0.0194), with a higher pH in miswak toothpaste.

CONCLUSIONS: Miswak herbal toothpaste possesses a potent antibacterial effect, yet its remineralization potential is questionable due to its inferior ion release that will affect the ion substantivity in saliva, which is an important factor in remineralization. High caries risk, Miswak, Fluoride, Antibacterial, Streptococcus mutans.

El-Rashidy, A. A., R. M. Abdelraouf, and N. A. Habib, Effect of two artificial aging protocols on color and gloss of single-shade versus multi-shade resin composites, , vol. 22, issue 1, pp. 321, 2022. AbstractWebsite

The long-term color stability and gloss retention of resin composites are among the crucial factors that affect the clinical longevity of esthetic restorations, especially in anterior teeth. This study evaluated the effect of artificial aging by immersion in different storage media and thermocycling on color and gloss of dental single-shade resin composite (Omnichroma) versus multi-shade one (Filtek Z350XT). One hundred resin-composite disc-shaped specimens were used, 50 from each group, Omnichroma and Filtek Z350XT. Ten specimens from each material acted as control group (incubated in saliva). For each material, 40 specimens were divided according to the artificial-aging protocol (immersion at 37 °C for 12 days or thermocycling for 10,000 cycles) and storage media (tea, red wine). Color and gloss were measured before and after artificial aging. Color difference (∆E00) was compared with perceptibility threshold and acceptability threshold. Data were statistically analyzed; independent t test was used to compare results between two tested materials, while two-way ANOVA was used to compare results among the different immersion media within the same material. Artificial aging (immersion or thermocycling) in tea and red wine led to significant color changes and gloss reduction in both materials (P < 0.05), in contrast to control group. Red wine produced highest color differences. Both dental resin-composites; the single-shade (Omnichroma) and multi-shade (Filtek Z350XT) displayed unacceptable discoloration and gloss reduction after artificial-aging in tea and red-wine by immersion or thermocycling simulating one-year clinical-service.

Radwan, I. A., D. Rady, S. El Moshy, M. M. S. Abbass, K. M. Sadek, A. A. El-Rashidy, A. E. El-Arab, and K. M Fawzy El-Sayed, "Current Trends and Future Outlooks of Dental Stem-Cell-Derived Secretome/Conditioned Medium in Regenerative Medicine", Handbook of Stem Cell Therapy, Singapore, Springer Nature Singapore, pp. 1035 - 1070, 2022. Abstract

Constructing biological substitutes that mimic the structure, architecture, and function of different tissues and organs is the ultimate goal of regenerative medicine. Adult mesenchymal stem/progenitor cells (MSCs) are considered the most widely researched cells in regenerative applications, yet several obstacles that challenge the safe and effective clinical translation of MSC-based therapies still exist. MSCs could partially exert their reparative and regenerative impact through a paracrine effect, mediated by the release of bioactive and trophic factors known as secretome, rather than the actual presence of the engrafted cells in the target site. In addition, MSCs have shown the ability to secrete these various bioactive molecules in their surrounding media (the conditioned media (CM)). MSC-secretome/CM is a set of proteins, lipids, nucleic acids, and trophic factors such as cytokines, chemokines, hormones, growth factors, and extracellular vesicles (EVs). Compared to nondental MSC secretome, dental MSC secretome/CM revealed a higher expression of proliferation-related, metabolic, transcriptional proteins and chemokines, as well as neurotrophins. Dental MSC secretome/CM exhibited experimentally tremendous biological effects, including immunomodulatory, anti-inflammatory, neuroprotective, osteogenic, angiogenic, and antiapoptotic effects, as well as the modulation of oxidative stresses. These aforementioned biological effects greatly explain the increasing interest in dental MSC secretome/CM as an acellular regenerative strategy for the treatment of various clinical diseases/injuries while alleviating the limitations and safety concerns associated with MSC-based therapies.

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