Introduction Although intracanal application of the triple antibiotic paste (TAP) may offer advantages (e.g., disinfection), this practice has been associated with significant drawbacks, including tooth discoloration. In this study, the color change of dentin was monitored during treatment with distinct TAP pastes and novel tubular-shaped three-dimensional (3D) electrospun scaffolds containing minocycline-MINO or doxycycline-DOX. Methods Two TAP pastes (TAPMINO–MINO, metronidazole/MET, and ciprofloxacin/CIP; and TAPDOX–DOX, MET, and CIP), four scaffold-based groups containing MINO or DOX, at distinct concentrations; one antibiotic-free scaffold (Scaffold); and one untreated group (Control) were investigated. Human canines were sectioned at the cemento-enamel junction (CEJ) and tubular-shaped scaffolds or paste were placed into the root canals and sealed. Color measurements (CIEL*a*b* parameters) were performed at baseline and after 1, 3, 7, 14, 21, and 28 days. Color changes were expressed as ΔE* values. In addition, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were also performed on the specimens after treatment. Data were analyzed using Repeated-measures ANOVA (alpha=0.05). Results All antibiotic-containing groups led to greater discoloration than the antibiotic-free groups. A severe discoloration occurred after 1 day. At the end of the experiment, antibiotic-treated samples exhibited crusts/agglomerates over the dentin surface, which totally or partially obliterated the dentinal tubules. The presence of MINO resulted in greater color change than DOX. Conclusion Scaffolds containing MINO or DOX produced similar color change to dentin when compared to their respective TAP systems, although DOX-related discoloration was less pronounced.

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This study investigated the antimicrobial and osteogenic properties of titanium (Ti) disks superficially modified with tetracycline (TCH)-incorporated polymer nanofibers. The experiments were carried out in two phases. The first phase dealt with the synthesis and characterization (i.e., morphology, mechanical strength, drug release, antimicrobial activity, and cytocompatibility) of TCH-incorporated fibers. The second phase was dedicated to evaluating both the antimicrobial and murine-derived osteoprecursor cell (MC3T3-E1) response of Ti-modified with TCH-incorporated fibers. TCH was successfully incorporated into the submicron-sized and cytocompatible fibers. All TCH-incorporated mats presented significant antimicrobial activity against periodontal pathogens. The antimicrobial potential of the TCH-incorporated fibers-modified Ti was influenced by both the TCH concentration and bacteria tested. At days 5 and 7, a significant increase in MC3T3-E1 cell number was observed for TCH-incorporated nanofibers-modified Ti disks when compared to that of TCH-free nanofibers-modified Ti-disks and bare Ti. A significant increase in alkaline phosphatase (ALP) levels on the Ti disks modified with TCH-incorporated nanofiber on days 7 and 14 was seen, suggesting that the proposed surface promotes early osteogenic differentiation. Collectively, the data suggest that TCH-incorporated nanofibers could function as an antimicrobial surface modifier and osteogenic inducer for Ti dental implants.