Aiah Abd El-Wahab El-Rashidy

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.

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.

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.

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.

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.

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.

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.

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.

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.

Mesenchymal stem/progenitor cells (MSCs) have a multi-differentiation potential into specialized cell types, with remarkable regenerative and therapeutic results. Several factors could trigger the differentiation of MSCs into specific lineages, among them the biophysical and chemical characteristics of the extracellular matrix (ECM), including its stiffness, composition, topography, and mechanical properties. MSCs can sense and assess the stiffness of extracellular substrates through the process of mechanotransduction. Through this process, the extracellular matrix can govern and direct MSCs' lineage commitment through complex intracellular pathways. Hence, various biomimetic natural and synthetic polymeric matrices of tunable stiffness were developed and further investigated to mimic the MSCs' native tissues. Customizing scaffold materials to mimic cells' natural environment is of utmost importance during the process of tissue engineering. This review aims to highlight the regulatory role of matrix stiffness in directing the osteogenic differentiation of MSCs, addressing how MSCs sense and respond to their ECM, in addition to listing different polymeric biomaterials and methods used to alter their stiffness to dictate MSCs' differentiation towards the osteogenic lineage.

Mesenchymal stem/progenitor cells (MSCs) are key players in regenerative medicine, relying principally on their differentiation/regeneration potential, immunomodulatory properties, paracrine effects, and potent homing ability with minimal if any ethical concerns. Even though multiple preclinical and clinical studies have demonstrated remarkable properties for MSCs, the clinical applicability of MSC-based therapies is still questionable. Several challenges exist that critically hinder a successful clinical translation of MSC-based therapies, including but not limited to heterogeneity of their populations, variability in their quality and quantity, donor-related factors, discrepancies in protocols for isolation, in vitro expansion and premodification, and variability in methods of cell delivery, dosing, and cell homing. Alterations of MSC viability, proliferation, properties, and/or function are also affected by various drugs and chemicals. Moreover, significant safety concerns exist due to possible teratogenic/neoplastic potential and transmission of infectious diseases. Through the current review, we aim to highlight the major challenges facing MSCs’ human clinical translation and shed light on the undergoing strategies to overcome them.

Regenerative medicine literature has proposed mesenchymal stem/progenitor cell- (MSC-) mediated therapeutic approaches for their great potential in managing various diseases and tissue defects. Dental MSCs represent promising alternatives to nondental MSCs, owing to their ease of harvesting with minimally invasive procedures. Their mechanism of action has been attributed to their cell-to-cell contacts as well as to the paracrine effect of their secreted factors, namely, secretome. In this context, dental MSC-derived secretome/conditioned medium could represent a unique cell-free regenerative and therapeutic approach, with fascinating advantages over parent cells. This article reviews the application of different populations of dental MSC secretome/conditioned medium in in vitro and in vivo animal models, highlights their significant implementation in treating different tissue' diseases, and clarifies the significant bioactive molecules involved in their regenerative potential. The analysis of these recent studies clearly indicate that dental MSCs' secretome/conditioned medium could be effective in treating neural injuries, for dental tissue regeneration, in repairing bone defects, and in managing cardiovascular diseases, diabetes mellitus, hepatic regeneration, and skin injuries, through regulating anti-inflammatory, antiapoptotic, angiogenic, osteogenic, and neurogenic mediators.

Dentin-pulp complex is a term which refers to the dental pulp (DP) surrounded by dentin along its peripheries. Dentin and dental pulp are highly specialized tissues, which can be affected by various insults, primarily by dental caries. Regeneration of the dentin-pulp complex is of paramount importance to regain tooth vitality. The regenerative endodontic procedure (REP) is a relatively current approach, which aims to regenerate the dentin-pulp complex through stimulating the differentiation of resident or transplanted stem/progenitor cells. Hydrogel-based scaffolds are a unique category of three dimensional polymeric networks with high water content. They are hydrophilic, biocompatible, with tunable degradation patterns and mechanical properties, in addition to the ability to be loaded with various bioactive molecules. Furthermore, hydrogels have a considerable degree of flexibility and elasticity, mimicking the cell extracellular matrix (ECM), particularly that of the DP. The current review presents how for dentin-pulp complex regeneration, the application of injectable hydrogels combined with stem/progenitor cells could represent a promising approach. According to the source of the polymeric chain forming the hydrogel, they can be classified into natural, synthetic or hybrid hydrogels, combining natural and synthetic ones. Natural polymers are bioactive, highly biocompatible, and biodegradable by naturally occurring enzymes or via hydrolysis. On the other hand, synthetic polymers offer tunable mechanical properties, thermostability and durability as compared to natural hydrogels. Hybrid hydrogels combine the benefits of synthetic and natural polymers. Hydrogels can be biofunctionalized with cell-binding sequences as arginine-glycine-aspartic acid (RGD), can be used for local delivery of bioactive molecules and cellularized with stem cells for dentin-pulp regeneration. Formulating a hydrogel scaffold material fulfilling the required criteria in regenerative endodontics is still an area of active research, which shows promising potential for replacing conventional endodontic treatments in the near future.

Composite 3D scaffolds combining natural polymers and bioceramics are promising candidates for bone tissue engineering (BTE). Zein, as a natural plant protein, offers several advantages, including biocompatibility, adequate strength properties, and low/no immunogenicity; however, it lacks bioactivity. Thus, composite zein: bioactive glass (BG) scaffolds are proposed as promising candidate for BTE applications, with silver-doping of bioactive glass providing an antibacterial effect against possible post-implantation infection. Therefore, the aim of this study was to investigate the in vitro antibacterial properties, biocompatibility, bioactivity and compressive strength of zein scaffolds containing silver-doped bioactive glass. BG nanoparticles, undoped and Ag-doped, were fabricated using the sol-gel method. 3D composite zein:BG scaffolds, containing 20 wt% BG, were prepared and their antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was assessed using the disc diffusion assay. Human osteoblast-like MG-63 cells were used to evaluate the in vitro biocompatibility of the prepared scaffold groups. In addition, the compressive strength of the scaffolds was determined using uniaxial compression strength testing and the scaffold interconnected porosity was measured using helium pycnometer. Disc diffusion assay showed that only zein scaffolds containing Ag-doped sol-gel BG are antibacterially positive against E. coli and S. aureus. Pure zein scaffolds and zein scaffolds containing sol-gel-derived BG showed no negative influence on the growth of MG-63 cells, as evident by the cells' ability to survive, proliferate, and function on these scaffolds. Moreover, incorporating sol-gel-derived BG into zein scaffolds at zein:BG of 80:20 ratio showed bioactive properties with adequate porosity without affecting the scaffolds' compressive strengths, which was similar to that of trabecular bone, suggesting that the new composites have potential for BTE applications in non-loaded bearing areas.