Efficacy of three-dimensional models for medical education: A systematic scoping review of randomized clinical trials

Exploring reliable photogrammetry techniques for 3D modeling in anatomical research and education

In anatomical research and education, three-dimensional visualization of anatomical structures is crucial for understanding spatial relationships in diagnostics, surgical planning, and teaching. While computed tomography (CT) and magnetic resonance imaging (MRI) offer valuable insights, they are often expensive and require specialized resources. This study explores photogrammetry as an affordable and accessible approach for 3D modeling in anatomical contexts. Two photogrammetry methods were compared: conventional open-source software (Colmap) and Apple's RealityKit Object Capture. Human C3 vertebrae were imaged with a 24 MP camera, with and without a cross-polarization filter. Reconstruction times, vertex distances, surface area, and volume measurements were compared to CT scans. Results revealed that the Object Capture method surpassed the conventional approach in reconstruction speed and user-friendliness. Both methods exhibited similar vertex distance from reference mesh and volume measurements, although the conventional approach produced larger surface areas compared to CT-based models. Cross-polarization filters eliminated the need for pre-processing and improved outcomes in challenging lighting conditions. This study demonstrates that photogrammetry, especially Object Capture, as a reliable and time-efficient tool for 3D modeling in anatomical research and education. It offers accessible alternatives to traditional techniques with advantages in texture mapping. While further validation of various anatomical structures is required, the accessibility and cost-effectiveness of photogrammetry make it a valuable asset for the field. In summary, photogrammetry would have the potential to revolutionize anatomical research and education by providing cost-effective, accessible, and accurate 3D modeling. The study underscores the promise of advancing anatomical research and education through the integration of photogrammetry with ongoing improvements in user-friendliness and accessibility.

Clinical application of instant 3D printed cast versus polymer orthosis in the treatment of colles fracture: a randomized controlled trial

BACKGROUND

The shortcomings of plaster in water resistance, air permeability, skin comfort, fixed stability and weight of wearing are still to be solved. 3D printed cast can overcome the above shortcomings. At present, there is a relative lack of data on the clinical application of 3D printed cast, probably due to its complexity, relatively long operating time, and high price. We aimed to compare and evaluate the short-term effectiveness, safety and advantages of 3D printed wrist cast versus polymer orthosis in the treatment of Colles fracture.

METHODS

Forty patients with Colles fracture in our hospital from June to December 2022 were selected and divided into an observation group (20 patients, treated with instant 3D printed cast) and a control group (20 cases, treated with polymer orthosis). Both groups treated with manual reduction and external fixation. The visual analogue scale (VAS), immobilization effectiveness and satisfaction scores, Disability of the Arm, Shoulder and Hand (DASH) score, complications and imaging data were collected and compared before immobilization and at 2, 6 and 12 weeks after the fracture.

RESULTS

VAS at 2 weeks after the fracture was significantly lower in the observation group than in the control group ( P < 0.05). The immobilization effectiveness and satisfaction scores at 6 weeks after the fracture were significantly higher in the observation group than in the control group (all P < 0.05). The DASH scores at 2 and 6 weeks after the fracture were significantly lower in the observation group than in the control group (all P < 0.05). There wasn't rupture of the printed cast or orthosis in both groups. There were 2 cases of skin irritation in the control group, and no skin irritation occurred in the observation group. The palmar tilt angle and ulnar inclination angle at 2 weeks and 12 weeks after the fracture were significantly higher in the observation group than in the control group (all P < 0.05).

CONCLUSIONS

Both instant 3D printed cast and polymer orthosis are effective in the treatment of Colles fracture. But instant 3D printed cast is better than polymer orthosis in areas of good clinical and imaging performance, and high patient satisfaction and comfort.

Advanced Strategies for the Fabrication of Multi-Material Anatomical Models of Complex Pediatric Oncologic Cases

The printing and manufacturing of anatomical 3D models has gained popularity in complex surgical cases for surgical planning, simulation and training, the evaluation of anatomical relations, medical device testing and patient-professional communication. 3D models provide the haptic feedback that Virtual or Augmented Reality (VR/AR) cannot provide. However, there are many technologies and strategies for the production of 3D models. Therefore, the aim of the present study is to show and compare eight different strategies for the manufacture of surgical planning and training prototypes. The eight strategies for creating complex abdominal oncological anatomical models, based on eight common pediatric oncological cases, were developed using four common technologies (stereolithography (SLA), selectie laser sinterning (SLS), fused filament fabrication (FFF) and material jetting (MJ)) along with indirect and hybrid 3D printing methods. Nine materials were selected for their properties, with the final models assessed for application suitability, production time, viscoelastic mechanical properties (shore hardness and elastic modulus) and cost. The manufacturing and post-processing of each strategy is assessed, with times ranging from 12 h (FFF) to 61 h (hybridization of FFF and SLS), as labor times differ significantly. Cost per model variation is also significant, ranging from EUR 80 (FFF) to EUR 600 (MJ). The main limitation is the mimicry of physiological properties. Viscoelastic properties and the combination of materials, colors and textures are also substantially different according to the strategy and the intended use. It was concluded that MJ is the best overall option, although its use in hospitals is limited due to its cost. Consequently, indirect 3D printing could be a solid and cheaper alternative.

Accuracy assessment of implant placement with versus without a CAD/CAM surgical guide by novices versus specialists via the digital registration method: an in vitro randomized crossover study

BACKGROUND

Many studies demonstrated that surgical guides might reduce discrepancies compared with freehand implant placement. This randomized crossover study aimed to assess the effects of approaches, practitioners' experience and learning sequences on the accuracy of single tooth implantation via digital registration method. No similar study was found.

METHODS

This in vitro randomized crossover study enrolled 60 novice students (Group S) and 10 experienced instructors (Group I). Sixty students were randomly and evenly assigned to two groups (Group SA and SB). In Group SA, 30 students first performed single molar implant on a simulation model freehand (Group SAFH), and then with a CAD/CAM surgical guide (Group SASG). In Group SB, another 30 students first performed guided (Group SBSG) and then freehand (Group SBFH). Ten instructors were also divided into Group IAFH/IASG (n = 5) and IBSG/IBFH (n = 5) following the same rules. The accuracy of implant placement was assessed by the coronal and apical distance (mm) and angular (°) deviations using the digital registration method. T tests and nonparametric tests were used to compare the results among different groups of approaches, experience and sequences.

RESULTS

For students, the coronal and apical distance and the angular deviations were significantly lower in surgical guide group than freehand group in total and in learning freehand first subgroup, but for learning surgical guide first subgroup the apical distance deviation showed no significant difference between two approaches. For students, the angular deviation of freehand group was significantly lower in learning surgical guide first group than learning freehand first group. For instructors, the coronal and apical distance and angular deviations showed no significant difference between two approaches and two sequences. For freehand approach, the coronal and apical distance and the angular deviations were significantly higher in student group than instructor group, while not significantly different between two groups for surgical guide approach.

CONCLUSIONS

For novices, using a surgical guide for the first implant placement may reduce the potential deviations compared with freehand surgery, and may reach a comparable accuracy with that of specialists. For simple single molar implantation, the surgical guide may not be significantly helpful for experienced specialists.

Efficacy of CAD/CAM technology in dental procedures performed by students: A systematic scoping review of randomized clinical trials

To assess the efficacy of computer-aided design/computer-aided manufacturing (CAD/CAM) in dental procedures performed by dental students.

METHODS

A systematic scoping review was performed. MeSH terms and keywords were specified to assess randomized clinical trials (RCTs) in all idioms.

RESULTS

Nine RCTs that include 520 students were selected. Two RCTs studied implant placement, and the rest of the trials explored implant impressions, intraoral scans, canal obturation, head positioning errors in panoramic images, deep caries and pulp exposure, diagnosis of temporomandibular disorders, and a tooth for restorations. Considering efficacy, variable results were found. The RCTs that explored implant impressions, deep caries and pulp exposure, and diagnosis of temporomandibular disorders showed better results when CAD/CAM technology was performed by students. Two RCTs that investigated implant placement presented contradictory outcomes; one showed better results when CAD/CAM systems were used while the other described similar results to conventional methods. The remaining RCTs did not find differences with conventional procedures. Considering the time spent during the procedures, two studies showed no differences between groups, while another indicated that the time spent was less for digital impressions (p < 0.001). A continuous decrease in scanning time was also perceived for all groups as skills in intraoral scanning augmented (p = 0.0005). Students indicated an interest in utilizing the CAD/CAM systems and recognized that their abilities were enhanced.

CONCLUSIONS

Considering the limitations of this review and the limited number of RCTs evaluated, students recognized that their skills improved using CAD/CAM systems; however, only in some specific procedures greater efficacy and less time spent were observed when this technology was used. Dental students also showed great interest in using these techniques.