A series of new benzothiazole hydrazide derivatives starting from 2-mercaptobenzothiazole have been synthesized. 2-hydrazinobenzothiazole [M1] was prepared by refluxing of a mixture of hydrazine hydrate. H2O (80%) with 2-mercaptobenzothiazole. The reaction of the compound [M1] with the synthesized esters and amino esters [M2-M7 afforded benzothiazole hydrazide derivatives [M8-M13]. Compounds [M2-M7] were prepared from the reaction of different amino acids and carboxylic acids with absolute ethanol in presence of concentrated sulfuric acid. The structures of all synthesized compounds were established on the basis of FT-IR and some of them by 1H-NMR. The synthesized compounds have been evaluated for antimicrobial activity against Gram-positive and Gram-negative bacteria. Among thirteen synthesized compounds, in which four compounds (M8-M12) exhibited promising antibacterial activity.

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Background Although dental implants have demonstrated very high success rates, they are susceptible to complications such as peri-implantitis that can lead to failure. Methods Twenty implants with surfaces grit-blasted using hydroxyapatite and acid-etched were randomly divided into four groups (five in each group). Three groups were assigned to laser treatments: Group I (erbium, chromium-doped: yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser), Group II (650-nm diode laser), and Group III (808-nm diode), and one control group, Group IV. The surface roughness parameters (roughness average(Ra) and root mean square roughness(Rq)) were measured using a non-contact optical profilometer and scanning electron microscope to evaluate the surface topography after the laser treatments. Results Significant differences were observed between the laser groups regarding the surface roughness Ra (3.56±0.26, 3.45±0.19, 3.77±0.42, p c =0.0004, p e =0.0002, p f =0.001) and Rq values (4.49±0.34, 4.35±0.26, 4.72±0.56, p c =0.0007, p e =0.0006, p f =0.002) and the control group (2.81±0.10; 3.57±0.19). However, no significant difference was observed between the different laser treatment modalities. The scanning electron microscope images revealed some morphological changes on the implant surfaces following laser treatment, but no melted morphology was observed. Conclusions The application of Er,Cr:YSGG, 650-nm diode laser, and 808-nm diode did not show melting changes on implant topography. However, some increase in surface roughness was detected. Further studies are recommended to assess the effectiveness of these laser settings on bacterial reduction and osseointegration.