3D extrusion printing of density gradients by variation of sinusoidal printing paths for tissue engineering and beyond

A cross-sectional study of the anatomy of the jaws of a central-European caucasian population using cone beam computer tomography as a prerequisite for designing pre-formed calcium phosphate cement scaffolds

PURPOSE

This study aims to measure the cortical and cancellous bone thickness in the upper and lower jaws, serving as a data template for developing pre-defined calcium phosphate cement primary implant forms. These measurements are crucial for creating a biphasic scaffold.

METHODS

Forty complete jaws were assessed for cortical bone shape and thickness using statistical analysis and specific software tools. Sex and age were considered, and four groups were created.

RESULTS

The cumulative thickness of the cortical layer varied from region to region. In both the upper and lower jaws, the cortical layer in the molar region was significantly thicker than in the frontal region. Within the alveolar process, cortical thickness increases with distance from the alveolar crest on both sides. The oral side of the lower jaw is significantly thicker than the vestibular side. For the upper jaw, no significant differences between the oral and vestibular sides were found in this study. Additionally, it is noteworthy that men have a significantly thicker cortical layer than women. Regarding age, no significant overall differences were found.

CONCLUSION

Mathematical analysis of anatomical forms using polynomial functions improves understanding of jaw anatomy. This approach facilitates the design of patient-specific scaffold structures, minimizing the need for costly and time-consuming planning and enabling more efficient implementation of optimal therapy.

Development and optimization of starch-based biomaterial inks and the effect of infill patterns on the mechanical, physicochemical, and biological properties of 3D printed scaffolds for tissue engineering

Plant-based hydrogels have wide application as scaffolds in tissue engineering and regenerative medicine due to their low cost and excellent biocompatibility. Scaffolds act as vehicles for cell-based therapeutics and regenerating diseased tissue. While there is a plethora of methods to generate hydrogels with tunable properties to mimic the tissue of interest, 3D bioprinting is a novel emerging technology with the capability to generate versatile patient-specific scaffolds typically embedded with tissue specific cells. Starch-based hydrogels are garnering attention in extrusion-based 3D printing, however owing to their poor mechanical strength and degradation render this material inefficient in its native form. Additionally, the effect of various printing process parameters on mechanical strength and bioactivity is poorly understood. In the present study, we investigate the use of starch and gelatin as composite biomaterial ink and its effect on mechanical, physical and biological properties. We also investigated printability of composite hydrogels with the aim to understand the correlation between two infill patterns and its effect on mechanical, physicochemical, and biological properties. Our results showed that the composite hydrogels had competent mechanical properties and suitable bioactivity when seeded with H9C2 cardiomyocytes. Rheometric analyses provided a broader insight into the required viscosity for printing and has a direct correlation with the composition of the hydrogel. Thus, the composite materials are found to have tissue-specific mechanical properties and may serve as a better, cheaper and personalized alternative to existing scaffolds for the fabrication of engineered cardiac tissue.

Three-Dimensional Plotted Calcium Phosphate Scaffolds for Bone Defect Augmentation—A New Method for Regeneration

For sinus grafting, different methods and materials are available. One possible shortcoming of particulate bone grafts is either overfilling or augmenting the planned implant area insufficiently. To overcome this risk and to determine the implant position prior augmentation, we present an approach using three-dimensional printed scaffolds. A patient with a remaining anterior dentition and bilateral severely atrophied posterior maxilla was seeking oral rehabilitation. The cone beam computed tomography (CBCT) showed residual bone heights between one and two millimeters. Following the three-dimensional reconstruction of the CBCT data, the positions of the implants were determined in areas 16 and 26. Three-dimensional scaffolds adapted to the topography of the sinus were virtually designed and printed using a calcium phosphate cement paste. Bilateral sinus floor augmentation applying the printed scaffolds with an interconnecting porosity followed. After nine months, a satisfying integration of the scaffolds was obvious. At the re-entry, vital bone with sufficient blood supply was found. One implant could be placed in positions 16 and 26, respectively. After five months, the implants could be uncovered and were provided with a temporary denture. The application of three-dimensionally printed scaffolds from calcium phosphate cement paste seems to be a promising technique to graft the severely atrophied posterior maxilla for the placement of dental implants.