Effect of titanium dioxide nanotubes in Ca(OH)2-based intracanal medicaments on odontoblast-like cells

This study investigated the effects of incorporating 3wt% titanium dioxide nanotubes (nTiO2) into calcium hydroxide [Ca(OH)2]-based intracanal medicament (ICM) formulations on the proliferation, viability, and mitochondrial metabolic activity of mouse dental papilla cells (MDPC-23). Five experimental groups were evaluated (n=3 per group): Cells (control), Calen, Calen + 3wt% nTiO2, Ultracal, and Ultracal + 3wt% nTiO2. Cell proliferation, viability, and mitochondrial metabolic activity were assessed using the Trypan Blue exclusion and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays at 24, 48, and 72 h. Data analysis included the Shapiro-Wilk and Levene tests and generalized linear models (p<0.05). At 24 and 48 h, both Ultracal and Ultracal + 3wt% nTiO2 showed significantly higher proliferation than the Calen groups (p<0.0001). The control group (Cells) exhibited the highest viable cell counts (p<0.0005). At 72 h, Calen + 3wt% nTiO2 showed the lowest proliferation compared with both the Cells and the Ultracal groups (p<0.0001). No significant differences were observed in non-viable cell counts or viable/non-viable ratios over time (p>0.05). Furthermore, Calen and Calen + 3 wt% nTiO2 at 24 and 48 h, as well as Calen + 3wt% nTiO2 at 72 h, demonstrated the lowest metabolic activity (p<0.0001), with no significant effect of nTiO2 (p>0.05). No significant intra-group differences over time were observed for the Cells or Ultracal groups (p=0.0608 and p=0.1417, respectively). Overall, the incorporation of nTiO2 did not adversely affect the biological parameters of Ca(OH)2-based ICMs assessed in this study. Further investigations are warranted to elucidate potential clinical implications.