Multi-directional forging (MDFing) of titanium drastically improved its mechanical properties due to the evolution of an ultrafine-grained structure. Forging strain was repeatedly applied while changing the forging axis during MDFing. Of note is the decreased elastic modulus of MDFed titanium (MDF-Ti) as compared to conventional coarse-grained pure Ti (Ti). In the present study, we evaluated bone’s response toward surface-treated MDF-Ti after implantation into the extraction sockets of rat maxillary molars. As surface treatments, acid (Acid, sulfuric acid at 120 °C for 75 s), alkali without post-heat (Alkali, NaOH at 60 °C for 24 h), and alkali with post-heat (Alkali-heat, subsequent heating at 600 °C for 1 h) treatments were employed. The presence of minute nanoscale dimples in the microscale dimples to form regular fractal structures on MDF-Ti surfaces was observed after Acid treatments. Structures of sponge-like porous networks after Alkali treatments and submicron fiber networks after Alkali-heat treatment were produced on the surfaces of both Ti and MDF-Ti. Surface-treated specimens were superhydrophilic. More crystal deposition was clearly observed on each surface-treated specimen after immersion in simulated body fluid for both Ti and MDF-Ti. The bone-to-implant contact (BIC) ratios of the Acid and Alkali-heat specimens were significantly higher than those of the untreated control (p < 0.05). Moreover, Acid and Alkali-heat treatment for MDF-Ti caused significantly greater BICs than that for Ti (p < 0.05). In conclusion, Acid or Alkali-heat treatment of MDF-Ti is useful for improving bone response.

Multi-directional forging (MDFing) can improve the various properties of metals and alloys due to the evolution of an ultrafinegrained structure. In the present study, electrochemical properties and corrosion behaviors in a fluoride solution of MDFed pure titanium (MDF-Ti) were evaluated by comparing with conventional coarse-grained pure titanium (Ti). The Eopen value of MDF-Ti was significantly higher than that of Ti. However, similar potentiodynamic polarization profiles were obtained for Ti and MDF-Ti. Immersion in NaF solution caused no severe corrosion to Ti or MDF-Ti. However, immersion in acidulate phosphate fluoride solution (APF) revealed that MDF-Ti had better corrosion resistance than Ti at shorter time immersion periods and was more susceptible to corrosion for longer immersion. Significantly less release of titanium was observed for MDF-Ti in shorter immersion periods in APF. In conclusion, MDF-Ti showed similar electrochemical behaviors to Ti and less susceptible to corrosion in shorter time APF immersion.

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Regarding anterior tooth defects, both patients and dentists are mainly interested in restoring esthetics. Loss of anterior teeth reduces tissue volume in most cases. Therefore, prosthesis-driven implant treatment that places the crown in an ideal position increases the importance of tissue management. Prosthetic designs may result in reduced surgical intervention and shorter treatment times. A patient-oriented strategy that fully considers the patient's requirements is necessary during planning treatment. This report discusses tissue management that considers prosthetic strategies using cantilevers and gum prostheses.