Implantation and Retrieval of Magnetic Nanobots for Treatment of Endodontic Re-Infection in Human Dentine

<div> <div> <div> <p>More than 10% of root canal treatments undergo failure worldwide due to remnant bacteria deep in the dentinal tubules located within the dentine tissue of human teeth. Owing to the complex and narrow geometry of the tubules, current techniques relying on passive diffusion of anti-bacterial agents are inadequate. Here, we present a new treatment method using actively maneuvered nanobots, which can be incorporated during standard root canal procedure. Our technique will enable dentists to execute procedures inside the dentine not yet possible by current state of the art. We demonstrate that magnetically driven nanobots can reach the depths of the tubules up to hundred times faster than current clinical practices. Subtle modifications of the magnetic drive allowed deep implantation of the nanobots isotopically distributed throughout the dentine, along with spatially controlled retrieval from selected areas. Finally, we demonstrate the integration of bactericidal therapeutic modality with the nanobots, thereby validating the tremendous potential of nanobots in dentistry, and nanomedicine in general. </p> </div> </div> </div>

Implantation and Retrieval of Magnetic Nanobots for Treatment of Endodontic Re-Infection in Human Dentine

<div> <div> <div> <p>More than 10% of root canal treatments undergo failure worldwide due to remnant bacteria deep in the dentinal tubules located within the dentine tissue of human teeth. Owing to the complex and narrow geometry of the tubules, current techniques relying on passive diffusion of anti-bacterial agents are inadequate. Here, we present a new treatment method using actively maneuvered nanobots, which can be incorporated during standard root canal procedure. Our technique will enable dentists to execute procedures inside the dentine not yet possible by current state of the art. We demonstrate that magnetically driven nanobots can reach the depths of the tubules up to hundred times faster than current clinical practices. Subtle modifications of the magnetic drive allowed deep implantation of the nanobots isotopically distributed throughout the dentine, along with spatially controlled retrieval from selected areas. Finally, we demonstrate the integration of bactericidal therapeutic modality with the nanobots, thereby validating the tremendous potential of nanobots in dentistry, and nanomedicine in general. </p> </div> </div> </div>

Color compatibility between dental structures and three different types of ceramic systems

Background To assess color compatibility between dental structures (human enamel and dentine) and three different types of ceramic systems. Methods Samples (1 and 2 mm-thick) of extracted tooth (containing dentine and enamel areas) and three ceramic systems with different shades and opacities (HT–High Translucent, T–Translucent) were prepared for this study: Vita Suprinity—VS (HT, T; A1, A2, A3, A3.5, B2, C2, D2) (Vita Zahnfabrik); Vita Enamic—VE (HT, T; 1M1, 1M2, 2M2, 3M2) (Vita Zahnfabrik) and Noritake Super Porcelain EX-3—NKT (A1, A2, A3, A3.5, B2, C2, D2) (Kuraray Noritake Dental). Reflectance measurements of all samples were performed over black backgrounds using a non-contact spectroradiometer (SpectraScan PR-670, Photo Research) under a CIE 45°/0° geometry. CIE L*a*b* color parameters were measured and CIELAB/CIEDE2000 color differences (ΔE00/ΔE*ab) and corresponding Coverage Error (CE) of ceramic system for dentine or enamel samples were calculated. Color data was analyzed using one-way ANOVA and post-hoc multiple comparisons tests. CE values were interpreted by comparisons with available 50:50% acceptability color threshold (AT) for dentistry. Results Statistically significant differences in lightness were found among all ceramic systems and human dentine (p < 0.001), while no significant differences were registered between enamel and VSHT, T and VEHT. 1 mm dentine showed no statistical differences with VST and VSHT for a* coordinate, while 2 mm dentine showed no significant differences (p > 0.05) with VEHT. Thin samples (1 mm) of dentine and enamel showed significant statistical differences (p < 0.05) for b* coordinate with less translucent materials (NKT, VET and VST). For dentine samples, none of the ceramic materials provided a CE lower than AT. VSHT provided the best CE for 1 mm-thick (CE00 = 1.7, CEab = 1.9) and for 2 mm-thick (CE00 = 2.3; CEab = 2.5) enamel samples. Conclusions Color coordinates of evaluated esthetic ceramic systems were statistically different from those of human dentine in almost all cases. The evaluated ZrO2 lithium silicate glass–ceramic (VS), with its two levels of translucency, provided lower CE values with human enamel samples while conventional feldspathic ceramic (NKT) and hybrid ceramic systems (VE) demonstrated a better color compatibility with dentin samples.

The long-term consequence of salivary contamination at various stages of adhesive application and clinically feasible remedies to decontaminate

Objective To analyse the bond quality in dentine post-ageing after salivary contamination and decontamination at different stages of dental adhesive application. Materials and methods A total of 1120 human dentine specimens were randomly allocated to 14 groups for four intervals (n = 20) to be treated with a self-etching (SE) and universal (U) adhesive. The saliva contamination and decontamination were implemented after surface preparation, after primer application (for SE) and after adhesive curing. The decontamination groups were either rinsed and air-dried or rinsed, air-dried and reapplied with adhesive. They were stored (37 °C, distilled water) for four intervals (1 week, 1 month, 3 months and 1 year) and subjected to shear bond strength (SBS) test at a crosshead speed of 0.5 mm/min. Result One-way ANOVA with Tukey’s test (α = 0.05) revealed significant reduction in SBS in all the groups in U adhesive compared with the control group at 1 week (p < 0.0001) and in SE when the contamination took place after primer application. However, decontamination improved the SBS in SE but not in U adhesive. The univariate analysis confirmed significant influences (p < 0.0001) seen by treatment procedure ($$ {\eta}_{\mathrm{p}}^2 $$ η p 2 =0.075), type of adhesive ($$ {\eta}_{\mathrm{p}}^2 $$ η p 2 = 0.328), ageing ($$ {\eta}_{\mathrm{p}}^2 $$ η p 2 = 0.13), experimental groups ($$ {\eta}_{\mathrm{p}}^2 $$ η p 2 = 0.518), and the stage of influence ($$ {\eta}_{\mathrm{p}}^2 $$ η p 2 = 0.60). Conclusion Saliva contamination is detrimental after primer application in SE but, decontamination regained the SBS and maintained it over time. In U adhesive, SBS deteriorated over time irrespective of the contamination. Clinical relevance Salivary contamination showed different influences on SBS at various stages of restoration with contemporary dental adhesives.