The objective of this work is to review the literature on the use of three-dimensional scaffolds obtained by printing for the regeneration of bone defects in the maxillofacial area. The research question asked was: what clinical experiences exist on the use of bone biomaterials manufactured by CAD/CAM in the maxillofacial area? Prospective and retrospective studies and randomized clinical trials in humans with reconstruction area in the maxillofacial and intraoral area were included. The articles had to obtain scaffolds for bone reconstruction that were designed by computer processing and printed in different materials. Clinical cases, case series, in vitro studies and those that were not performed in humans were excluded. Six clinical studies were selected that met the established inclusion criteria. The selected studies showed heterogeneity in their objectives, materials used and types of regenerated bone defects. A high survival rate was found for dental implants placed on 3D-printed scaffolds, with rates ranging from 94.3% to 98%. The materials used included polycaprolactone, coral-derived hydroxyapatite, biphasic calcium phosphate (BCP) and bioceramics. The use of CAD/CAM technology is seen as key for satisfying variations in the shapes and requirements of different fabrics and size variations between different individuals. Furthermore, the possibility of using the patient’s own stem cells could revolutionize the way bone defects are currently treated in oral surgery. The results indicate a high survival rate of dental implants placed on 3D-printed scaffolds, suggesting the potential of this technology for bone regeneration in the maxillofacial mass.

Interim fixed prostheses are used provisionally to provide esthetics and maintain function until placement of the definitive prosthesis. Polymethyl methacrylate (PMMA) has been widely used as an interim material but has mechanical limitations that can be improved with the addition of nanomaterials such as graphene fibers (PMMA-G). However, studies on the biocompatibility of this material are lacking. The purpose of this in vitro study was to determine the biocompatibility and cytotoxic effects of PMMA compared with PMMA-G in periodontal ligament stem cells (PDLSCs) by measuring the viability and cell apoptosis of those cells subjected to different concentrations of both compounds by elution, as well as the surface characterization of these materials. Sterile Ø20×15-mm specimens of PMMA and PMMA-G were covered with Dulbecco modified Eagle medium for 24 hours to be the subsequent eluent. PDLSCs were seeded in 6 plates of 96 wells at dilutions 1/1, 1/2, 1/4, and 1/8 for each material. Three plates for the cell viability assay with MTT and 3 plates for the cell apoptosis assay with Hoechst 33342 staining were used in turn to subdivide the measurements at 24, 48, and 72 hours. The Kruskal-Wallis test was used to compare the data obtained in the different dilutions at different times and the Mann-Whitney test to compare both materials. Topography and wetting were analyzed for surface characterization. The Student t test of paired measurements was used to compare the different surfaces for each parameter (α=.05 for all tests). In both the cell viability assay (MTT) and the cell apoptosis assay, the test did not identify statistically significant differences in PMMA and PMMA-G with respect to the control group in the different dilutions at different times (P>.05). When comparing both materials, no statistically significant differences (P=.268) were found in either trial. PMMA-G had lower roughness and kurtosis and higher wetting than PMMA. Both PMMA and PMMA-G were found to be biocompatible materials with no significant differences between them after cell viability and apoptosis testing. PMMA-G had higher wettability and lower roughness than PMMA.

To compare laboratory production time, clinical adjustment time, and patient-reported comfort of three occlusal splint fabrication techniques (heat-cured acrylic, vacuum-adapted acrylic, and CAD-CAM 3D-printed splints) in a pilot feasibility study. Three participants each received three splints, one fabricated with each technique. Laboratory production time, chairside adjustment time, and comfort (VAS) were recorded. Vacuum-adapted splints required the shortest laboratory production time (mean = 92 min, SD = 25.35). Heat-cured splints required longer processing (mean = 114 min, SD = 6.08). The CAD-CAM splints showed the longest total workflow duration (mean = 133 min, SD = 6.08), although they required less manual technician work. Intraoral adjustment times were similar between heat-cured and vacuum-adapted splints (means = 28 min and 26.66 min, respectively). None of the CAD-CAM splints seated fully at delivery, preventing proper adjustment. Vacuum-adapted splints received the highest comfort scores. Within the limitations of this pilot study with three participants, vacuum-adapted and heat-cured splints showed clinically acceptable performance and comparable adjustment times. CAD-CAM splints reduced manual workload but suffered from significant seating and fit issues, indicating the need for workflow refinement before clinical implementation. Even as splint fabrication is moving towards a more digital workflow, the old methods, especially vacuum-adapted splints, continue to deliver timely and comfortable results to patients. Further studies with more participants need to be done so that there can be a clear digital splint fabrication workflow.

This in vitro study aimed to determine the flexural strength and modulus of elasticity of two bisacrylic resins for temporary crowns at different thicknesses, i.e., Structur 3 and Structur Premium, and to compare them with each other. Sixty samples were prepared, thirty of each material, which were made at different thicknesses (1 mm, 1.5 mm, and 2 mm). The dimensions followed the UNE-EN ISO 178:2019 standard, with a length of 24 mm, a width of 10 mm, and the thicknesses described. Materials were subjected to a three-point bending test. For the modulus of elasticity, statistically significant differences were observed between the 1.5 mm and 2 mm thicknesses of Structur 3 material. For Structur Premium, statistically significant differences were observed between the thicknesses 1 mm and 1.5 mm as well as between 1 mm and 2 mm thickness. With respect to flexural strength, no statistically significant differences were observed for either material at the different thicknesses. Significant differences were observed between the materials for both flexural strength and modulus of elasticity, being higher for Structur Premium: Structur Premium has a higher flexural strength and modulus of elasticity than Structur 3. There are significant differences for the modulus of elasticity but not for the flexural strength between thicknesses.

Polylactic acid (PLA) and its composites with hydroxyapatite (HA) have been studied in the field of bone repair applications. The objective of this study was to evaluate the biocompatibility of PLA/HA at different concentrations and to analyze early adhesion of periodontal ligament stem cells (PDLSCs). Cells were seeded in two 24-well plates, each containing six disk-shaped samples of PLA/HA (10%, 15% and 20%) and six control samples and then examined using scanning electron microscopy. Twelve 96-well plates were prepared with different elution concentrations (1/1, 1/2, 1/4, and 1/8) to assess biocompatibility using MTT cell viability and Hoechst 33342 assays at 24, 48, and 72 h. PLA/HA 20% showed the highest early adhesion (p = 0.0057), with cells adopting a more elongated morphology. The MTT assay revealed no differences in viability between concentrations (p = 0.6196), whereas the Hoechst assay demonstrated the highest viability for PLA/HA 20% (p < 0.0001). Overall, PLA promoted cell adhesion, with the 20% formulation providing the greatest adhesion. All concentrations maintained high viability, and longer culture time enhanced both adhesion and viability.