Ethanol c2h5oh

Zinc-chloride (ZnCl₂), potassium dichromate (K₂Cr₂O₇-molecular weight (MW) = 294.19 g, an assay of 99%)), ethanol (C₂H₅OH), and urea (NH₂CONH₂), were procured from Sigma Aldrich, USA. Hydrochloric acid (HCl, M.W = 36.46 g, acid-metric assay of 30–34%) was procured from SD-Fine Chem Limited, Mumbai-India. 1,5–Diphenyl-Carbazide used as a complexing reagent for the Cr⁶⁺ ions assessment was procured from BDHZ-chemicals LTD Poole-England. AO7 dye (Orange II) (AO7) (C. I. 15,510) (C₁₆H₁₁N₂NaO₄S) (M.W = 350 g) and AB14 dye (C.I. 22,110) (C₂₆H₁₆N₄Na₂O₈S₂) (M.W = 622.547 g) were procured from ISMA dye corporation, Egypt. All the chemicals used for this research were of reasonable rating and were not purified for further usage.

Chemicals, namely chloroform (CHCl₃), analytical grade acetone (C₆H₆O), ethanol (C₂H₅OH), and reagents required for preparation of the simulated body fluid (SBF), such as NaCl, NaHCO₃, KCl, K₂HPO₄·3H₂O, MgCl₂·6H₂O, HCl, CaCl₂, Na₂SO₄ and (CH₂OH)₃CNH₂ were purchased from Sigma-Aldrich Chemie GmbH (Germany).
Two (1 × 1) cm² area plates from titanium 4th grade (Ti) and 316L medical grade stainless steel (SS) were utilized as deposition substrates. SS composition was: 64.26 wt% Fe, 18.51 wt% Cr, 12 wt% Ni, 2.13 wt% Mo, 1.44 wt% Mn, 0.58 wt% Cu, 0.56 wt% Si, 0.0265 wt% C, 0.0036 wt% S and smaller concentration of other elements. Prior to deposition, the plates were machined by mechanical polishing to a roughness within 2–4 μm and cleaned with ethanol and deionized water in an Elma X-Tra 30 H ultrasonic bath.
Bioactive glasses (BG) are degradable, synthetic materials containing key elements and molecules which boost osteogenesis. They have been in use for nearly 50 years [27 (link),28 (link)] in the orthopedics field due to their ability to convert and built on surface an apatite layer during dissolution, like hydroxycarbonated apatite, which promotes osteogenesis. BG are based on an amorphous mixture of oxides (SiO₂-Na₂O-K₂O-CaO-MgO-P₂O₅). The chosen BG contains 56.5% SiO₂, 15% CaO, 11% Na₂O, 8.5% MgO, 6% P₂O₅, and 3% K₂O (in wt%). It is fabricated following the protocol described in Refs. [29 (link),30 (link)]. Poly(methyl methacrylate)—PMMA, (C₅H₈O₂)n, is a biopolymer widely used in both medical applications [31 ] and in some optical systems (contact lens as transmit light up to 93% [32 (link)]) or the flat panel industry [33 ]. It is also used as denture base material due to its high stability in the physiological environment, and ease of handling and repair [34 (link)].
Neem (Azadirachta indica, family Meliaceae) is an Indian medicinal plant used in traditional Ayurveda treatment of various infections. It is recommended for dental and oral hygiene (chewing Neem sticks is still the most common method of cleaning the mouth in Indian rural population) [35 (link)]. It was shown that Neem exhibits anti-infective, anti-inflammatory, antioxidant, anticariogenic, or immunomodulatory activities, which recommend it for endodontics and periodontal surgery [36 (link)]. There exists evidence of the antibacterial effectiveness of Neem extracts on the frequent microorganisms causing dental infections: Staphylococcus aureus, Streptococcus mutans, Candida albicans, or Enterococcus faecalis. [37 (link),38 (link),39 (link)]. A total of 2% aqueous extract of Neem chewing sticks inhibited in vitro the growth of Staphylococci, Streptococci and E. coli [40 (link)]. Ethanolic extract of Neem leaf demonstrated inhibitory effect on Methicillin-resistant Staphylococcus aureus biofilm by decreasing its ability to form large clusters [41 (link)]. The methanolic extract of Neem proved robust antimicrobial activity against polymicrobial dentinal biofilms of common endodontic pathogens, such as Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Candida albicans [42 (link)]. In addition, Neem extract showed significant anti-inflammatory activity in vitro [43 (link)]. Neem used in our experiments is commercial in form of capsules which contain 480 mg Neem leaf powder.

To obtain zinc-doped hydroxyapatite coated with dextran solutions by the sol-gel method we used calcium nitrate (Ca(NO₃)₂∙4H₂O, Sigma-Aldrich, St. Louis, MA, USA), zinc nitrate (Zn(NO₃)₂·6H₂O, Alfa Aesar, Karlsruhe, Germany; 99.99% purity), ammonium hydrogen phosphate ((NH₄)₂HPO₄), Alfa Aesar, Karlsruhe, Germany; 99.99% purity), triethanolamine (C₆H₁₅NO₃, Sigma-Aldrich, St. Louis, MA, USA ≥ 99.0% (GC) purity), dextran (H(C₆H₁₀O₅)_xOH, (MW ∼ 40,000), Merck, Kenilworth, NJ, USA) and ethanol (C₂H₅OH, Merck, Kenilworth, NJ, USA). Bi-distilled water was also used in the synthesis of dextran-coated zinc-doped hydroxyapatite.

Analytical reagent grade ferric nitrate nonahydrate Fe(NO₃)₃ · 9H₂O, cobaltous nitrate hexahydrate Co(NO₃)₂ · 6H₂O, sodium hydroxide NaOH, 99% ethanol C₂H₅OH, and other all chemicals were purchased from Sigma Aldrich (St. Louis, MO, USA).