Consumer vs. High-End 3D Printers for Guided Implant Surgery-An In Vitro Accuracy Assessment Study of Different 3D Printing Technologies

Advances in Digital Light Processing (DLP) Bioprinting: A Review of Biomaterials and Its Applications, Innovations, Challenges, and Future Perspectives

Digital light processing (DLP) technology stands out as a groundbreaking method in the field of biomedical engineering that enables the production of highly precise structures using photopolymerizable materials. Smart materials such as shape memory polymers, hydrogels, and nanocomposites are used as ideal materials for personalized medicine applications thanks to their properties such as superior mechanical strength, biocompatibility, and sensitivity to environmental stimuli in DLP technology. The integration of these materials with DLP enables the production of functional and complex structures, especially in areas such as bone and soft tissue engineering, drug delivery, and biosensor production. However, limited material diversity, scalability problems in production processes, and technical difficulties in optimizing bioprinting parameters are among the main obstacles in this field. This study systematically examines the role of smart biomaterials in DLP-based bioprinting processes. It addresses the innovative applications of these materials in tissue engineering and regenerative medicine. It also comprehensively evaluates its contributions to biomedical applications and discusses future research areas to overcome current limitations.

Medical 3D Printing Using Material Jetting: Technology Overview, Medical Applications, and Challenges

Material Jetting (MJT) 3D printing (3DP) is a specific technology that deposits photocurable droplets of material and colored inks to fabricate objects layer-by-layer. The high resolution and full color capability render MJT 3DP an ideal technology for 3DP in medicine as evidenced by the 3DP literature. The technology has been adopted globally across the Americas, Europe, Asia, and Australia. While MJT 3D printers can be expensive, their ability to fabricate highly accurate and multi-color parts provides a lucrative opportunity in the creation of advanced prototypes and medical models. The literature on MJT 3DP has expanded greatly as of late, in part aided by the lowering costs of the technology, and this report is the first review to document the applications of MJT in medicine. Additionally, this report portrays the technological information behind MJT 3DP, cases involving fabricated MJT 3DP models from the University of Cincinnati 3DP lab, as well as the challenges of MJT in a clinical setting, including cost, expertise in managing the machines, and scalability issues. It is expected that MJT 3DP, as imaging and segmentation technologies undergo future improvement, will be best poised with representing the voxel-level-variations captured by radiologic-image-sets due to its capacity for voxel-level-control.

Accuracy of the over-preparation technique in implant surgery in the maxillary anterior region: an in vitro study

BACKGROUND

In the maxillary anterior region, differences in bone density along the drilling path can impact the accuracy of implant placement despite the use of a surgical guide. Hence, the aim of this in vitro study was to investigate the accuracy of implant placement using the over-preparation technique in different drilling environments in the maxillary anterior region.

METHODS

Three experimental models (a, b, and c) were designed and fabricated to simulate the following drilling environments (n = 60 each): unhealed bone, less dense bone, and dense bone after tooth extraction. The models were subjected to implant cavity preparation and placement using the over-preparation technique (group OPT) and conventional surgical guide technique (group CGT). Differences between the actual positions and the planned positions of the implants were calculated.

RESULTS

The deviations of the implants in the group OPT in Model a and Model b were significantly smaller than those in the group CGT (P < 0.05). Among the group OPT, Model c presented with the smallest deviation, followed by Model b and Model a (P < 0.05), and the CGT group showed the same trend.

CONCLUSIONS

In the maxillary anterior region, differences in bone density along the drilling path can adversely affect the accuracy of implant placement. These discrepancies can be significantly minimized using the over-preparation technique.

Influence of two different printing methods on the accuracy of full-guided implant insertion - a laboratory study in undergraduate dental students

OBJECTIVES

The aim of the present study was to compare the accuracy of fully guided implant insertion in vitro achieved by two fabrication methods in a cohort of undergraduates. We hypothesized that both methods achieve a comparable accuracy.

METHODS

Surface scans and cone beam computed tomography images of 48 mandibular models were matched. For each model, two surgical guides enabling a fully guided implant insertion in the region of the first molar on the left or the right side were virtually designed. Fabrication by either Digital Light Processing (DLP) or Fused Filament Fabrication (FFF) followed. Subsequently, 96 implants using the guides were inserted into the models by 48 undergraduate students. The accuracy of the implant insertion was assessed radiographically, followed by statistical analysis. Additionally, all participants completed a questionnaire.

RESULTS

The implants inserted using guides made by DLP showed a higher accuracy compared to guides made by FFF. The mean three-dimensional deviation was 1.94 ± 1.05 vs. 3.35 ± 2.03 degrees (p < 0.001). The evaluation of the questionnaires revealed mainly theoretical knowledge and a pronounced interest in implant dentistry.

DISCUSSION

The main hypothesis has to be rejected as there were statistically significant differences in accuracy. However, it is possible to teach students the principles of guided implant dentistry and the digital workflow. Furthermore, the initial and running costs for the FFF workflow are substantially lower enabling a higher practicability for undergraduate education.

CONCLUSION

Despite the lower accuracy of the templates made from FFF the method seems to be suitable for laboratory hands-on courses for undergraduates.

Three-Dimensional-Printed Photopolymer Resin Materials: A Narrative Review on Their Production Techniques and Applications in Dentistry

Additive manufacturing (3D printing) has transformed dentistry by providing solutions with high precision and accuracy achieved through digital workflows, which facilitate the creation of intricate and personalized structures. Additionally, 3D printing promotes cost efficiency by reducing material waste and errors while enabling on-demand production, minimizing the need for extensive inventories. Recent advancements in 3D-printed resin materials have enhanced their clinical applications by improving mechanical strength, biocompatibility, esthetics, and durability. These innovations have facilitated the fabrication of complex and patient-specific structures, such as dental prostheses, surgical guides, and orthodontic appliances, while significantly reducing production time and material waste. Ongoing research and innovation are expected to strengthen resin properties, including strength, translucency, and durability, broadening their clinical applications. The ongoing evolution of 3D printing technology is poised to play a critical role in driving personalized treatments, streamlining clinical workflows, and shaping the future of dental care. This narrative review comprehensively examines the production techniques and clinical applications of 3D-printed photopolymer resins across various dental specialties, including prosthodontics, orthodontics, pediatric dentistry, maxillofacial surgery, periodontology, endodontics, and conservative dentistry. Additionally, the review provides insight into the transformative impact of these technologies on patient care, highlights existing challenges, and suggests future directions for advancing resin properties and their integration into routine dental practice.

The Effects of Light Crystal Display 3D Printers, Storage Time and Steam Sterilization on the Dimensional Stability of a Photopolymer Resin for Surgical Guides: An In Vitro Study

BACKGROUND

Implant surgical guides manufactured in-house using 3D printing technology are widely used in clinical practice to translate virtual planning to the operative field.

AIM

The present in vitro study investigated the dimensional changes of 3D surgical guides printed in-house using Shining 3D surgical guide resin (SG01).

MATERIALS AND METHODS

Five test bodies, varying in shape and dimensions, were designed using computer-aided design (CAD) software and manufactured using three different Light Crystal Display (LCD) 3D printers (AccuFab-L4D, Elegoo Mars Pro 3, and Zortrax Inspire). Specific printing and post-processing parameters for the SG01 resin were set to produce 25 test bodies (5 of each shape) from each of the three printers, resulting in a total of 75 samples. The dimensional changes were evaluated using a digital calliper at four different time points: immediately after printing (T0), one month after storage (T1), immediately after sterilization (T2), and one month after sterilization (T3).

RESULTS

All the test bodies showed deviations from the overall CAD reference value of 12.25 mm after printing and post-processing (T0) and following steam sterilization (T2). Similar trends were observed for the effect of storage times at T1 and T3. The AccuFab prints demonstrated a better dimensional stability than the Elegoo and Zortrax samples.

CONCLUSIONS

The LCD 3D printers, sterilization, and storage times influenced the dimensional stability of the test bodies made with SGO1 resin.

Chess-like Pieces Realized by Selective Laser Sintering of PA12 Powder: 3D Printing and Micro-Tomographic Assessment

The paper highlights the realization of 3D-printed parts with complex geometries, such as chess-like pieces, using polyamide 12 (PA12) as polymeric powder via selective laser sintering (SLS). The research activity focuses on the study of the powder printability, the optimization of the printing parameters, and the tomographic evaluation of the printed objects. Morphological analyses were carried out to study the PA12 powder microstructure considering that SLS required specific particle size distribution and shape, able to guarantee a good flowability necessary to take part in a sintering process. DSC and TG analyses were performed to determine the sintering window and the crystallinity degree, and to evaluate the thermal stability of the PA12 powder due to the importance of the powder processability for the SLS process. The novelty lies in the realization of chess-like pieces very challenging to print via SLS due to their different and highly detailed structures, and the in-depth analysis of the dimensional accuracy evaluated by micro-tomography. The 3D-printed samples obtained show high printing quality and dimensional stability. The μ-CT analysis also confirms the key role of the object shape and section changes on the final porosity of the chess-like pieces.

Achieving automated and high-precision in situ analysis of the dimensional accuracy and dynamic deformation of 3D-printed surgical templates: an in vitro study

PURPOSE

To demonstrate the viability of a coordinate-measuring machine (CMM) for the geometric analysis of 3D printed surgical templates.

METHODS

The template was designed and modified by adding 18 cylindrical landmarks for CMM test and then classified into five groups according to the slicing software and resins (opaque and transparent): Streamflow-O, Streamflow-T, Shapeware-T, Rayware-T and Polydevs-T (N = 3). Three standing times (0 w, 1 w, and 2 w) were included to observe possible deformation. All the measurements were performed automatically by the CMM through a preset program. The Euclidian distance (dxyz) was regarded as the representation of global dimension accuracy, and displacements in the x-, y-, and z-axes were also calculated.

RESULTS

The average dxyz values of Streamflow-O, Streamflow-T, Shapeware-T, Rayware-T and Polydev-T are 32.6 μm, 31.3 μm, 56.4 μm, 96.4 μm, and 55.3 μm, respectively. Deviations were mainly induced by the upward bending of the free end region (positive direction of the z-axis). Different resins did not have a significant influence on the dimensional accuracy. Moreover, deformation appeared to be negligible after 2 weeks of storage, and the z-axis displacements were only approximately 30 μm at week 1 and 10 μm at week 2.

CONCLUSIONS

The deviations of the DLP-printed template are induced mainly by z-axis displacements and are determined by the processing accuracy. After 2 weeks, the dimensional stabilities of these templates are reliable, which is encouraging for clinicians. Moreover, the CMM is preliminarily demonstrated to be a feasible tool for achieving automated geometric analysis of surgical templates.

Dimensional Accuracy in 3D Printed Medical Models: A Follow-Up Study on SLA and SLS Technology

Background: With the rise of new 3D printers, assessing accuracy is crucial for obtaining the best results in patient care. Previous studies have shown that the highest accuracy is achieved with SLS printing technology; however, SLA printing technology has made significant improvements in recent years. Methods: In this study, a realistic anatomical model of a mandible and skull, a cutting guide for mandibular osteotomy, and a splint for orthognathic surgery were replicated five times each using two different 3D printing technologies: SLA and SLS. Results: The SLA group had a median trueness RMS value of 0.148 mm and a precision RMS value of 0.117 mm. The SLS group had a median trueness RMS value of 0.144 mm and a precision RMS value of 0.096 mm. There was no statistically significant difference in RMS values between SLS and SLA technologies regarding trueness. Regarding precision, however, the RMS values for SLS technology were significantly lower in the splint and cutting guide applications than those printed with SLA technology. Conclusions: Both 3D printing technologies produce modern models and applications with equally high dimensional accuracy. Considering current cost pressures experienced by hospitals, the lower-cost SLA 3D printer is a reliable choice for point-of-care 3D printing.

Accuracy of surgical guides manufactured with four different 3D printers. A comparative in vitro study

OBJECTIVES

The aim of this study was to assess the accuracy of surgical guides manufactured with four different 3D printers..

METHODS

Forty-eight surgical guides (BlueSky Plan, BlueSky Bio) were produced using four different 3D printers, with strict adherence to each manufacturer's instructions. The printers used were three digital light processing (DLP) printers (SolFlex170, VC; Nextdent5100, ND, and D30+Rapidshape, RS) and one stereolithographic (SLA) printer (Formlabs3B+, FL). The study evaluated the trueness and precision of the overall surface, the region of interest (RoI) (occlusal and guide zone), the repeatability in several batches, and the guide hole's diameter and xyz axes. The printed guides were digitized and compared with the CAD design control specimen (Control X, Geomagic). Descriptive statistics and Kruskal-Wallis tests with post-hoc Mann-Whitney tests were performed (α=0.05).

RESULTS

Differences in trueness and precision were found between groups in the overall zone and RoI (p = 0.00). The ND group demonstrated the highest repeatability. Only the RS group exhibited a comparable guide hole diameter to the master specimen (5.27±2.12 mm; p = 0.104). No statistical differences were observed between groups in the x and z axes. However, in the y-axis, the VC group displayed statistically significant differences (p = 0.01).

CONCLUSIONS

The results showed that the DLP groups had better overall accuracy, while the SLA group had the best results in the RoI. The manufacturer's workflows demonstrated a high reproducibility between batches in the RoI. The RS group had values most similar values to the guide hole diameter of the master specimen, with minimal deviations in guide hole orientation.

CLINICAL SIGNIFICANCE

Implant position can be affected by the accuracy of the 3D printed surgical guide. Therefore, it is critical to analyze the final dimensions and the direction of the guide hole using available printing technologies.

Case report: One-stage craniectomy and cranioplasty digital workflow for three-dimensional printed polyetheretherketone implant for an extensive skull multilobular osteochondosarcoma in a dog

Objective

To report a digital workflow for use and long-term outcome of cranioplasty with a 3D-printed patient-specific Polyetheretherketone (PEEK) implant in a 12-y-old German Shepherd dog after surgical removal of an extensive occipital bone multilobular osteochondrosarcoma (MLO).

Study design

Retrospective case report.

Animal

A 12-year-old neutered female German Shepherd dog was presented with facial deformity, blindness, tetraparesis, and ataxia. Magnetic resonance imaging (MRI) and computed tomography (CT) identified a large skull-based mass extending extra-and intracranially with severe compression of the cerebellum and occipital lobes of the cerebrum.

Methods

One-stage decompressive craniectomy using virtual surgical planned 3D-printed craniotomy cutting guides and the Misonix BoneScalpel® and reconstruction with a patient-specific 3D-printed PEEK cranial implant.

Results

3D-printed craniectomy cutting guides allowed an adequate fit of the cranial implant to the original skull. Misonix BoneScalpel® allowed performing a safe and extensive craniectomy. Postoperative CT (8 weeks after surgery) confirmed the PEEK cranial implant to be in place and without implant rejection. Clinically, the neurological examination identified only a right-hind limb delay in proprioception 8 weeks postoperatively, which remained unchanged at 18 months after surgery. Adjunctive treatment included metronomic chemotherapy. Eighteen months after surgery the dog passed away for reasons unrelated to the MLO, no implant-related complications were reported.

Conclusion

3D-printed craniectomy cutting guides, patient-specific PEEK cranial implant, and metronomic chemotherapy can lead to a successful long-term outcome in dogs with extensive skull MLO.

Clinical significance

PEEK is an alternative biomaterial that can be used successfully for skull reconstruction.

Current applications of 3D printing in dental implantology: A scoping review mapping the evidence

OBJECTIVES

This scoping review aimed to identify the available evidence in the use of 3D printing technology in dental implantology. Due to the broad scope of the subject and its application in implantology, three main areas of focus were identified: (1) customized dental implants, (2) manufacturing workflow for surgical implant guides, and (3) related implant-supported prostheses factors, which include the metallic primary frameworks, secondary ceramic or polymer superstructures, and 3D implant analog models.

MATERIALS AND METHODS

Online databases (Medline, Cochrane, Embase, and CINAHL) were used to identify the studies published up to February 2023 in English. Two experienced reviewers performed independently the screening and selection among the 1737 studies identified. The articles evaluated the additive manufacturing (AM) technology, materials, printing, and post-processing parameters regarding dental implantology.

RESULTS

The 132 full-text studies that met the inclusion criteria were examined. Thirteen studies of customized dental implants, 22 studies about the workflow for surgical implant guides, and 30 studies of related implant-supported prostheses factors were included.

CONCLUSIONS

(1) The clinical evidence about AM titanium and zirconia implants is scarce. Early data on survival rates, osseointegration, and mechanical properties are being reported. (2) 3D printing is a proven manufacturing technology to produce surgical implant guides. Adherence to the manufacturer's instructions is crucial and the best accuracy was achieved using MultiJet printer. (3) The quality of 3D printed prosthetic structures and superstructures is improving remarkably, especially on metallic alloys. However, better marginal fit and mechanical properties can be achieved with milling technology for metals and ceramics.

Accuracy of additively manufactured and steam sterilized surgical guides by means of continuous liquid interface production, stereolithography, digital light processing, and fused filament fabrication

Different printing technologies can be used for prosthetically oriented implant placement, however the influence of different printing orientations and steam sterilization remains unclear. In particular, no data is available for the novel technology Continuous Liquid Interface Production. The objective was to evaluate the dimensional accuracy of surgical guides manufactured with different printing techniques in vertical and horizontal printing orientation before and after steam sterilization. A total of 80 surgical guides were manufactured by means of continuous liquid interface production (CLIP; material: Keyguide, Keyprint), digital light processing (DLP; material: Luxaprint Ortho, DMG), stereolithography (SLA; Surgical guide, Formlabs), and fused filament fabrication (FFF; material: Clear Base Support, Arfona) in vertical and horizontal printing orientation (n = 10 per subgroup). Spheres were included in the design to determine the coordinates of 17 reference points. Each specimen was digitized with a laboratory scanner after additive manufacturing (AM) and after steam sterilization (134 °C). To determine the accuracy, root mean square values (RMS) were calculated and coordinates of the reference points were recorded. Based on the measured coordinates, deviations of the reference points and relevant distances were calculated. Paired t-tests and one-way ANOVA were applied for statistical analysis (significance p < 0.05). After AM, all printing technologies showed comparable high accuracy, with an increased deviation in z-axis when printed horizontally. After sterilization, FFF printed surgical guides showed distinct warpage. The other subgroups showed no significant differences regarding the RMS of the corpus after steam sterilization (p > 0.05). Regarding reference points and distances, CLIP showed larger deviations compared to SLA in both printing orientations after steam sterilization, while DLP manufactured guides were the most dimensionally stable. In conclusion, the different printing technologies and orientations had little effect on the manufacturing accuracy of the surgical guides before sterilization. However, after sterilization, FFF surgical guides exhibited significant deformation making their clinical use impossible. CLIP showed larger deformations due to steam sterilization than the other photopolymerizing techniques, however, discrepancies may be considered within the range of clinical acceptance. The influence on the implant position remains to be evaluated.

Setting up a biomodeling, virtual planning, and three-dimensional printing service in Uruguay

Virtual surgical planning and three-dimensional (D) printing are rapidly becoming essential for challenging and complex surgeries around the world. An Ibero-American survey reported a lack of awareness of technology benefits and scarce financial resources as the two main barriers to widespread adoption of 3-D technologies. The Pereira Rossell Hospital Center is a publicly funded maternal and pediatric academic clinical center in Uruguay, a low-resource Latin American country, that successfully created and has been running a 3-D unit for 4 years. The present work is a step-by-step review of the 3-D technology implementation process in a hospital with minimal financial investment. References to training, software, hardware, and the management of human resources are included. Difficulties throughout the process and future challenges are also discussed.

Investigating the implant position reproducibility of optical impressions obtained using an intraoral scanner and 3D-printed models fabricated using an intraoral scanner

PURPOSE

This study aims to examine the effect of the size of the intraoral scanning area on implant position reproducibility and compare the implant position reproducibility of plaster models fabricated using the silicone impression technique, the digital model of an intraoral scanner, and three-dimensional (3D)-printed models fabricated using an intraoral scanner.

METHODS

Scanbodies were attached to an edentulous model with six implants (master model) and were scanned using a dental laboratory scanner to obtain basic data. The plaster model was fabricated using the open-tray method (IMPM; n = 5). The master model was then scanned in various implant areas using an intraoral scanner to obtain data (IOSM; n = 5); the scanning data of six scanbodies were used to fabricate the 3D-printed models (3DPM; n = 5) using a 3D printer. Scanbodies were attached to the implant analogs of the IMPM and 3DPM models and data were obtained using a dental laboratory scanner. The basic data and IMPM, IOSM, and 3DPM data were superimposed to calculate the concordance rate of the scanbodies.

RESULTS

The concordance rate of intraoral scanning decreased as the number of scanbodies increased. Significant differences were observed between the IMPM and IOSM data, and between the IOSM and 3DPM data; however, the IMPM and 3DPM data did not differ significantly.

CONCLUSIONS

The implant position reproducibility of the intraoral scanner decreased with an increase in the scanning area. However, ISOM and 3DPM may provide higher implant position reproducibility than plaster models fabricated using IMPM.

Comparative Verification of the Accuracy of Implant Models Made of PLA, Resin, and Silicone

Polylactic acid (PLA) has gained considerable attention as an alternative to petroleum-based materials due to environmental concerns. We fabricated implant models with fused filament fabrication (FFF) 3D printers using PLA, and the accuracies of these PLA models were compared with those of plaster models made from silicone impressions and resin models made with digital light processing (DLP). A base model was obtained from an impact-training model. The scan body was mounted on the plaster, resin, and PLA models obtained from the base model, and the obtained information was converted to stereolithography (STL) data by the 3D scanner. The base model was then used as a reference, and its data were superimposed onto the STL data of each model using Geomagic control. The horizontal and vertical accuracies of PLA models, as calculated using the Tukey-Kramer method, were 97.2 ± 48.4 and 115.5 ± 15.1 μm, respectively, which suggests that the PLA model is the least accurate among the three models. In both cases, significant differences were found between PLA and gypsum and between the PLA and resin models. However, considering that the misfit of screw-retained implant frames should be ≤150 µm, PLA can be effectively used for fabricating implant models.

Can Steam Sterilization Affect the Accuracy of Point-of-Care 3D Printed Polyetheretherketone (PEEK) Customized Cranial Implants? An Investigative Analysis

Polyetheretherketone (PEEK) has become the biomaterial of choice for repairing craniofacial defects over time. Prospects for the point-of-care (POC) fabrication of PEEK customized implants have surfaced thanks to the developments in three-dimensional (3D) printing systems. Consequently, it has become essential to investigate the characteristics of these in-house fabricated implants so that they meet the necessary standards and eventually provide the intended clinical benefits. This study aimed to investigate the effects of the steam sterilization method on the dimensional accuracy of POC 3D-printed PEEK customized cranial implants. The objective was to assess the influence of standard sterilization procedures on material extrusion-based 3D-printed PEEK customized implants with non-destructive material testing. Fifteen PEEK customized cranial implants were fabricated using an in-house material extrusion-based 3D printer. After fabrication, the cranial implants were digitalized with a professional-grade optical scanner before and after sterilization. The dimensional changes for the 3D-printed PEEK cranial implants were analyzed using medically certified 3D image-based engineering software. The material extrusion 3D-printed PEEK customized cranial implants displayed no statistically significant dimensional difference with steam sterilization (p > 0.05). Evaluation of the cranial implants’ accuracy revealed that the dimensions were within the clinically acceptable accuracy level with deviations under 1.00 mm. Steam sterilization does not significantly alter the dimensional accuracy of the in-house 3D-printed PEEK customized cranial implants.

Additive manufacturing technologies in the oral implant clinic: A review of current applications and progress

Additive manufacturing (AM) technologies can enable the direct fabrication of customized physical objects with complex shapes, based on computer-aided design models. This technology is changing the digital manufacturing industry and has become a subject of considerable interest in digital implant dentistry. Personalized dentistry implant treatments for individual patients can be achieved through Additive manufacturing. Herein, we review the applications of Additive manufacturing technologies in oral implantology, including implant surgery, and implant and restoration products, such as surgical guides for implantation, custom titanium meshes for bone augmentation, personalized or non-personalized dental implants, custom trays, implant casts, and implant-support frameworks, among others. In addition, this review also focuses on Additive manufacturing technologies commonly used in oral implantology. Stereolithography, digital light processing, and fused deposition modeling are often used to construct surgical guides and implant casts, whereas direct metal laser sintering, selective laser melting, and electron beam melting can be applied to fabricate dental implants, personalized titanium meshes, and denture frameworks. Moreover, it is sometimes required to combine Additive manufacturing technology with milling and other cutting and finishing techniques to ensure that the product is suitable for its final application.

Monitoring the Calibration of In-Office 3D Printers

Most desktop 3D printers lack features that allow manual calibration of printer parameters. It is crucial to assess the accuracy of printing to minimize the margin of error and variance between each print. Therefore, this study aimed to develop a method for monitoring the calibration of in-office 3D printers. A calibration coupon was designed to have a tolerance and dimensions that define nominal geometry and allow the measurement of variances occurring in X−Y axes and curvature. Ten printing cycles were run on two stereolithography (SLA) 3D printers with two different resins. Additionally, the coupons were positioned in five positions on the build platform to assess errors caused by differences in positioning. Measurements were made on the X and Y axes. No statistical difference was noted between the coupons being printed in different positions on the build platform and between the two resins at both X and Y axes of measurement (p > 0.05). Desktop 3D printers currently lack a standardized calibration protocol, which provides a closed loop for design and manufacturing of printed parts. The coupon in this study will allow monitoring the calibration of desktop 3D printers to ensure high-quality printing.

Novel and accurate 3D-Printed surgical guide for mandibular reconstruction with integrated dental implants

PURPOSE

Patients with mandibular defects due to trauma or infiltrated disease are in a need of functional mandibular implants that will completely restore the function of their lower jaw. One of the most important roles of well-functioning jaw is mastication, a complex mechanism. A conventional approach used in oral and maxillofacial surgery accomplish this aim via two major surgeries- mandibular reconstruction and surgical placement of dental implants. Little work has been done on combining the two surgeries into with using Additive Manufacturing (AM) and digital planning.

MATERIAL AND METHODS

This case study offers a mandibular implant design solution with pre-positioned dental implants that can reduce the requirement to only one surgery. Mandibular implant was designed using 3-Matic software (Materialise, Belgium). Positions for dental implants were restoratively-driven and planned on the designed mandibular implant in Blue Sky Plan 4 software (Blue Sky Bio, USA) and placed prior to mandibular reconstruction using a 3D-printed surgical guide. Finite Element Analysis (FEA) was used to evaluate the mechanical behaviour of the 3D-printed surgical guide during dental implant placement.

RESULTS

The surgical guide was fabricated using SLA and stress distribution was evaluated in ANSYS Workbench FEM software (Ansys Inc Swanson, Houston, USA). Results showed that the designed surgical guide can withstand the forces occurring during the surgery.

CONCLUSION

The proposed method substantially reduces the surgical procedure and recovery time, increases the accuracy, and allows for a predictable restorative solution that can be visualised from the beginning.

Guide for starting or optimizing a 3D printing clinical service

Three-dimensional (3D) printing has applications in many fields and has gained substantial traction in medicine as a modality to transform two-dimensional scans into three-dimensional renderings. Patient-specific 3D printed models have direct patient care uses in surgical and procedural specialties, allowing for increased precision and accuracy in developing treatment plans and guiding surgeries. Medical applications include surgical planning, surgical guides, patient and trainee education, and implant fabrication. 3D printing workflow for a laboratory or clinical service that produces anatomic models and guides includes optimizing imaging acquisition and post-processing, segmenting the imaging, and printing the model. Quality assurance considerations include supervising medical imaging expert radiologists' guidance and self-implementing in-house quality control programs. The purpose of this review is to provide a workflow and guide for starting or optimizing laboratories and clinical services that 3D-print anatomic models or guides for clinical use.

Impact of Steam Autoclaving on the Mechanical Properties of 3D-Printed Resins Used for Insertion Guides in Orthodontics and Implant Dentistry

Guided implant placement has been shown to be more accurate than free-handed insertion. Still, implant position deviations occur and could possibly pose risks. Thus, there is a quest to identify factors that might impair the accuracy of implantation protocols using templates. This study aimed to investigate the influence of autoclaving cycles (cycle 1: 121 °C, 1 bar, 20.5 min; cycle 2: 134 °C, 2 bar, 5.5 min) on the Vickers hardness and flexural modulus of five different materials used for 3D-printed insertion guides. The specimens were subjected to Vickers hardness tests, showing significant changes in the Vickers hardness for two and three materials out of five for cycle 1 and 2, respectively. The results of the three-point bending tests (n = 15 specimens per material) showed decreasing flexural moduli after autoclaving. However, changes were significant only for one material, which presented a significant decrease in the flexural modulus after cycle 2. No significant changes were detected after cycle 1. In conclusion, our findings show that autoclaving can alter the mechanical properties of the templates to some extent, especially with cycle 2. Whether these modifications are associated with dimensional changes of the templates and reduced accuracy of the implantation protocols remains to be investigated.

Accuracy of DICOM-DICOM vs. DICOM-STL Protocols in Computer-Guided Surgery: A Human Clinical Study

Guided implant surgery can enhance implant placement positioning, increasing predictability and decreasing postoperative complications., To date, the best protocol to be used for template realization is still unknown. Thus, the aim herein was to clinically compare the accuracy of two different protocols. A total of 48 implants were divided into Group A (24 implants), in which a stereolithographic template was realized using the digital imaging and communications in medicine (DICOM) data arrived from cone beam computer tomographies (CBCTs) (patients and prothesis alone), and Group B (24 implant), in which a standard intraoral stent with a standardized extraoral support was used for patients’ intraoral impressions and CBCT. The preimplant virtual planning and postsurgery CBCT images of both groups were superimposed, and differences were registered in terms of average deviations at the platform (a) and implant apex (b), mean depth change (c), and angular deviation (d). The results demonstrated that there were no statistically significant differences between groups (p = 0.76) for the parameters measured. However, statistically significant differences (p < 0.05) were found between maxillary and mandible implant surgery, as the latter showed greater accuracy. Additional studies are necessary to further reduce discrepancies between planning and surgical procedures.

A Retrospective Digital Analysis of Contour Changing after Tooth Extraction with or without Using Less Traumatic Surgical Procedures

BACKGROUND

The present retrospective analysis aimed to compare two different single tooth extraction surgical approaches in both premolar and molar areas: less traumatic magneto-electrical versus conventional tooth extraction in minimizing the edentulous ridge volume loss.

METHODS

In the present retrospective control trial, 48 patients who underwent one-tooth extraction, were allocated either to control (28 sites treated with conventional tooth extraction procedures) or test group (20 subjects treated with less traumatic tooth extraction procedures by tooth sectioning and magnetoelectric roots subluxation). Intraoperatively (during tooth extraction surgery just after the subsequent filling of the alveolar socket with the sterile fast re-absorbable gelatin sponge), and then four months later, contours of the sockets were acquired through a laser intra-oral scanner. The digitally superimposed models were converted to dicom (Digital Imaging and Communications in Medicine) format first, then volumetric and area evaluations were performed with a DentaScan tool package. Non-parametric tests were applied with a level of significance set at p < 0.01.

RESULTS

significant reductions of anatomical features were observed four months later in all the groups (p-values < 0.001) with volume losses leading to a final alveolar ridge volume of 0.87 ± 0.34 cm³ for atraumatic extractions and 0.66 ± 0.19 cm³ for conventional extractions. No significant differences were registered for outcomes related to the basal surface variables. When just molar tooth were considered, the outcomes relating to volume loss between baseline and four months (ΔV) and its percentage (ΔV%) showed a better behavior in the less traumatic procedure (ΔV = -0.30 ± 0.10 cm³ and ΔV% = -22.3 ± 8.4%) compared to the conventional extractions (ΔV = -0.59 ± 0.10 cm³ and ΔV% = -44.3 ± 5.8%) with p-values < 0.0001.

CONCLUSIONS

at four months, the less traumatic tooth extraction procedures by tooth sectioning and magnetoelectric root subluxation seemed to be able to better preserve the volume of the alveolar crest (reduction close to 22% with less traumatic extraction in molar sites) when compared to subjects treated with the conventional tooth extraction techniques.