3D Printed composite for simulating thermal and mechanical responses of the cortical bone in orthopaedic surgery

Experimental investigation of ultrasonic assisted coating on three-point bending behavior of 3D printed polymeric bone plates for biomedical applications

3D printed Poly Lactic Acid (PLA) bone plates exhibit limited three-point bending strength, restricting their viability in biomedical applications. The application of polydopamine (PDM) enhances the three-point bending strength by undergoing covalent interactions with PLA molecular structure. However, the heavy nature of PDM particles leads to settling at the container base at higher coating solution concentrations. This study investigates the impact of ultrasonic-assisted coating parameters on the three-point bending strength. Utilizing Response Surface Methodology (RSM) for statistical modeling, the study examines the influence of ultrasonic vibration power (UP), coating solution concentration (CC), and submersion time (TIME). RSM optimization recommended 100 % UP, 6 mg/ml CC, and 150 min TIME, resulting in maximum three-point bending strength of 83.295 MPa. Microscopic images from the comparative analysis revealed non-uniform coating deposition with mean thickness of 6.153 µm under normal coating. In contrast, ultrasonic-assisted coating promoted uniform deposition with mean thickness of 18.05 µm. The results demonstrate that ultrasonic-assisted coating induces PDM particle collision, preventing settling at the container base, and enhances three-point bending strength by 7.27 % to 23.24 % compared to the normal coating condition. This study emphasizes on the potential of ultrasonic-assisted coating to overcome the limitations of direct immersion coating technique.

A Data-Driven Methodology to Comprehensively Assess Bone Drilling Using Radar Plots

Background

The study aims to develop a data-driven methodology to assess bone drilling in preparation for future clinical trials in residency training. The existing assessment methods are either subjective or do not consider the interdependence among individual skill factors, such as time and accuracy. This study uses quantitative data and radar plots to visualize the balance of the selected skill factors.

Methods

In the experiment, straight vertical drilling was assessed across 3 skill levels: expert surgeons (N = 10), intermediate residents (postgraduate year-2-5, N = 5), and novice residents (postgraduate year-1, N = 10). Motion and force were measured for each drilling trial, and data from multiple trials were then converted into 5 performance indicators, including overshoot, drilling time, overshoot consistency, time consistency, and force fluctuation. Each indicator was then scored between 0 and 10, with 10 being the best, and plotted into a radar plot.

Results

Statistical difference (p < 0.05) was confirmed among 3 skill levels in force, time, and overshoot data. The radar plots revealed that the novice group exhibited the most distorted pentagons compared with the well-formed pentagons observed in the case of expert participants. The intermediate group showed slight distortion that was between the expert and novice groups.

Conclusion/Clinical Relevance

This research shows the utility of radar plots in drilling assessment in a comprehensive manner and lays the groundwork for a data-driven training scheme to prepare novice residents for clinical practice.

An objective assessment for bone drilling: A pilot study on vertical drilling

The purpose of this study is to propose a quantitative assessment scheme to help with surgical bone drilling training. This pilot study gathered and compared motion and force data from expert surgeons (n = 3) and novice residents (n = 6). The experiment used three-dimensional printed bone simulants of young bone (YB) and osteoporotic bone (OB), and drilling overshoot, time, and force were measured. There was no statistically significant difference in overshoot between the two groups (p = 0.217 for YB and 0.215 for OB). The results, however, show that the experts took less time (mean = 4.01 s) than the novices (mean = 9.98 s), with a statistical difference (p = 0.003 for YB and 0.0001 for OB). In addition, the expert group performed more consistently than the novices. The force analysis further revealed that experts used a higher force to drill the first cortical section and a noticeably lower force in the second cortex to control the overshoot (approximate reduction of 5.5 N). Finally, when drilling time and overshoot distance were combined, the motion data distinguished the skill gap between expert and novice drilling; the force data provided insight into the drilling mechanism and performance outcomes. This study lays the groundwork for a data-driven training scheme to prepare novice residents for clinical practice.

The Application and Challenge of Binder Jet 3D Printing Technology in Pharmaceutical Manufacturing

Three-dimensional (3D) printing is an additive manufacturing technique that creates objects under computer control. Owing to the rapid advancement of science and technology, 3D printing technology has been widely utilized in processing and manufacturing but rarely used in the pharmaceutical field. The first commercial form of Spritam® immediate-release tablet was approved by FDA in 2015, which promoted the advancement of 3D printing technology in pharmaceutical development. Three-dimensional printing technology is able to meet individual treatment demands with customized size, shape, and release rate, which overcomes the difficulties of traditional pharmaceutical technology. This paper intends to discuss the critical process parameters of binder jet 3D printing technology, list its application in pharmaceutical manufacturing in recent years, summarize the still-open questions, and demonstrate its great potential in the pharmaceutical industry.

Translating Imaging Into 3D Printed Cardiovascular Phantoms

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3D printed patient specific phantoms can visualize complex cardiovascular anatomy

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Common imaging modalities for 3D printing are CCT and CMR

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Material jetting/PolyJet and stereolithography are widely used printing techniques

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Standardized validation is warranted to compare different 3D printing technologies

Translation of imaging into 3-dimensional (3D) printed patient-specific phantoms (3DPSPs) can help visualize complex cardiovascular anatomy and enable tailoring of therapy. The aim of this paper is to review the entire process of phantom production, including imaging, materials, 3D printing technologies, and the validation of 3DPSPs. A systematic review of published research was conducted using Embase and MEDLINE, including studies that investigated 3DPSPs in cardiovascular medicine. Among 2,534 screened papers, 212 fulfilled inclusion criteria and described 3DPSPs as a valuable adjunct for planning and guiding interventions (n = 108 [51%]), simulation of physiological or pathological conditions (n = 19 [9%]), teaching of health care professionals (n = 23 [11%]), patient education (n = 3 [1.4%]), outcome prediction (n = 6 [2.8%]), or other purposes (n = 53 [25%]). The most common imaging modalities to enable 3D printing were cardiac computed tomography (n = 131 [61.8%]) and cardiac magnetic resonance (n = 26 [12.3%]). The printing process was conducted mostly by material jetting (n = 54 [25.5%]) or stereolithography (n = 43 [20.3%]). The 10 largest studies that evaluated the geometric accuracy of 3DPSPs described a mean bias <±1 mm; however, the validation process was very heterogeneous among the studies. Three-dimensional printed patient-specific phantoms are highly accurate, used for teaching, and applied to guide cardiovascular therapy. Systematic comparison of imaging and printing modalities following a standardized validation process is warranted to allow conclusions on the optimal production process of 3DPSPs in the field of cardiovascular medicine.

Prosthodontics Using Removable Platform Switching Technologies (Multiunit, On1) as Exemplified by Conical Connection Implant Systems for Early and Immediate Loading

The removable platform switching technology (multiunit, Оn1) was tested intraoperatively using the passive placement technique as exemplified by a conical connection implant system, which makes it possible to visually control the placement of these platforms with respect to the alveolar bone in the correct orthopedic position. The technology is characterized by a rapid epithelialization of tissues around the base platform until the final integration of the implant, minimal trauma in the emergence profile zone, and an improved minimally invasive orthopedic protocol for working on a removable platform switching base.

Additive manufacturing pertaining to bone: Hopes, reality and future challenges for clinical applications

For the past 20 years, the democratization of additive manufacturing (AM) technologies has made many of us dream of: low cost, waste-free, and on-demand production of functional parts; fully customized tools; designs limited by imagination only, etc. As every patient is unique, the potential of AM for the medical field is thought to be considerable: AM would allow the division of dedicated patient-specific healthcare solutions entirely adapted to the patients' clinical needs. Pertinently, this review offers an extensive overview of bone-related clinical applications of AM and ongoing research trends, from 3D anatomical models for patient and student education to ephemeral structures supporting and promoting bone regeneration. Today, AM has undoubtably improved patient care and should facilitate many more improvements in the near future. However, despite extensive research, AM-based strategies for bone regeneration remain the only bone-related field without compelling clinical proof of concept to date. This may be due to a lack of understanding of the biological mechanisms guiding and promoting bone formation and due to the traditional top-down strategies devised to solve clinical issues. Indeed, the integrated holistic approach recommended for the design of regenerative systems (i.e., fixation systems and scaffolds) has remained at the conceptual state. Challenged by these issues, a slower but incremental research dynamic has occurred for the last few years, and recent progress suggests notable improvement in the years to come, with in view the development of safe, robust and standardized patient-specific clinical solutions for the regeneration of large bone defects.

Effects of temperature increase during surgical drilling in acrylic resin

BACKGROUND

Acrylic resin is employed for drilling bone biomodels. Since drilling causes temperature rise, the mechanical properties of thermoplastic acrylic resin can be altered, consequently affecting drilling properties. However, it is currently unclear how this temperature increase impacts drilling.

OBJECTIVE

This study reports the effects of temperature rise on both mechanical and drilling properties through experiments in which acrylic resin is drilled under machining conditions employed in surgical operations.

METHODS

Drilling tests were performed using a surgical drill on medical acrylic resin under dry conditions to observe generated cutting chips and measure drilling properties such as torque, drilling time, and temperature rise. Dynamic mechanical analysis measurements were performed to consider temperature effects.

RESULTS

According to the morphological classification of the cutting chips, the drilling process is divided into three phases corresponding with the generation of cylindrical helix, waved, and rounded nubby chips respectively. During drilling, the temperature of the chips can exceed the glass transition temperature (100∘C) resulting in decreased viscoelasticity, which is associated with decreased torque.

CONCLUSIONS

While drilling acrylic resin under surgical machining conditions, increasing temperature can decrease torque and morphologically change cutting chips due to the decrease in mechanical properties above the glass transition temperature.