METHODS: The PubMed database and Google scholar were browsed by keywords of 3-D printing, drug delivery, and personalised medicine. The data about techniques employed in the manufacturing of 3-D printed medicines and the application of 3-D printing technology in the fabrication of individualised medicine were collected, analysed and discussed.
RESULTS: Numerous techniques can fabricate 3-D printed medicines however, printing-based inkjet, nozzle-based deposition and laser-based writing systems are the most popular 3-D printing methods which have been employed successfully in the development of tablets, polypills, implants, solutions, nanoparticles, targeted and topical dug delivery. In addition, the approval of Spritam® containing levetiracetam by FDA as the primary 3-D printed drug product has boosted its importance. However, some drawbacks such as suitability of manufacturing techniques and the available excipients for 3-D printing need to be addressed to ensure simple, feasible, reliable and reproducible 3-D printed fabrication.
CONCLUSION: 3-D printing is a revolutionary in pharmaceutical technology to cater the present and future needs of individualised medicines. Nonetheless, more investigations are required on its manufacturing aspects in terms cost effectiveness, reproducibility and bio-equivalence.
METHODS: The Z Printer 450 (3D Systems, Rock Hill, SC) reprinted 10 sets of models for each category of crowding (mild, moderate, and severe) scanned using a structured-light scanner (Maestro 3D, AGE Solutions, Pisa, Italy). Stone and RP models were measured using digital calipers for tooth sizes in the mesiodistal, buccolingual, and crown height planes and for arch dimension measurements. Bland-Altman and paired t test analyses were used to assess agreement and accuracy. Clinical significance was set at ±0.50 mm.
RESULTS: Bland-Altman analysis showed the mean bias of measurements between the models to be within ±0.15 mm (SD, ±0.40 mm), but the 95% limits of agreement exceeded the cutoff point of ±0.50 mm (lower range, -0.81 to -0.41 mm; upper range, 0.34 to 0.76 mm). Paired t tests showed statistically significant differences for all planes in all categories of crowding except for crown height in the moderate crowding group and arch dimensions in the mild and moderate crowding groups.
CONCLUSIONS: The rapid prototyping models were not clinically comparable with conventional stone models regardless of the degree of crowding.
Methods: A patient-specific 3D-printed breast model was generated using 3D-printing techniques for the construction of the hollow skin and fibroglandular region shells. Then, the T1 relaxation times of the five selected materials (agarose gel, silicone rubber with/without fish oil, silicone oil, and peanut oil) were measured on a 3T MRI system to determine the appropriate ones to represent the MR imaging characteristics of fibroglandular and adipose tissues. Results were then compared to the reference values of T1 relaxation times of the corresponding tissues: 1,324.42±167.63 and 449.27±26.09 ms, respectively. Finally, the materials that matched the T1 relaxation times of the respective tissues were used to fill the 3D-printed hollow breast shells.
Results: The silicone and peanut oils were found to closely resemble the T1 relaxation times and imaging characteristics of these two tissues, which are 1,515.8±105.5 and 405.4±15.1 ms, respectively. The agarose gel with different concentrations, ranging from 0.5 to 2.5 wt%, was found to have the longest T1 relaxation times.
Conclusions: A patient-specific 3D-printed breast phantom was successfully designed and constructed using silicone and peanut oils to simulate the MR imaging characteristics of fibroglandular and adipose tissues. The phantom can be used to investigate different MR breast imaging protocols for the quantitative assessment of breast density.
PURPOSE: The purpose of this in vitro study was to evaluate the crestal strain around 2 implants to support mandibular overdentures when placed at different positions.
MATERIAL AND METHODS: Edentulous mandibles were 3-dimensionally (3D) designed separately with 2 holes for implant placement at similar distances of 5, 10, 15, and 20 mm from the midline, resulting in 4 study conditions. The complete denture models were 3D designed and printed from digital imaging and communications in medicine (DICOM) images after scanning the patient's denture. Two 4.3×12-mm dummy implants were placed in the preplanned holes. Two linear strain gauges were attached on the crest of the mesial and distal side of each implant (CH1, CH2, CH3, and CH4) and connected to a computer to record the electrical signals. Male LOCATOR attachments were attached, the mucosal layer simulated, and the denture picked up with pink female nylon caps. A unilateral and bilateral force of 100 N was maintained for 10 seconds for each model in a universal testing machine while recording the maximum strains in the DCS-100A KYOWA computer software program. Data were analyzed by using 1-way analysis of variance, the Tukey post hoc test, and the paired t test (α=.05).
RESULTS: Under bilateral loading, the strain values indicated a trend with increasing distance between the implants with both right and left distal strain gauges (CH4 and CH1). The negative (-ve) values indicated the compressive force, and the positive (+ve) values indicated the tensile force being applied on the strain gauges. The strain values for CH4 ranged between -166.08 for the 5-mm and -251.58 for the 20-mm position; and for CH1 between -168.08 for the 5-mm and -297.83 for the 20-mm position. The remaining 2 mesial strain gauges for all 4 implant positions remained lower than for CH4 and CH1. Under unilateral-right loading, only the right-side distal strain gauge CH4 indicated the increasing trend in the strain values with -147.5 for the 5-mm, -157.17 for the 10-mm, -209.33 for the 15-mm, and -234.75 for the 20 mm position. The remaining 3 strain gauges CH3, CH2, and CH1 ranged between -28.33 and -107.17. For each position for both implants, significantly higher (P