Interdisciplinary all-on-four® concept for mandibular jaw in dental education - do students benefit from individual 3d printed models from real patient cases?

PURPOSE: Digitalization is assuming increasing significance in dental education, as dental students are increasingly exposed to digital implant planning and contemporary technologies such as 3D printing. In this study, we present a cohort analysis aimed at assessing the potential benefits derived from the utilization of 3D prints to seamlessly translate planned procedures into real-life applications. METHODS: 21 dental students participated in a virtual planning and hands-on course across two cohorts (C1: n = 10, C2: n = 11). The virtual implant planning phase involved the placement of four implants on an atrophic lower jaw model. Subsequently, Cohort 1 (C1) executed the implantation procedure on a prefabricated hands-on model, while Cohort 2 (C2) engaged with 3D prints representing their individual implant planning during the hands-on session. Subjective assessments of knowledge, skills, and the perceived utility of 3D prints were conducted through pre- and post-course questionnaires, utilizing a 5-point scale. RESULTS: In the subjective evaluation, 17 out of 21 participants expressed a positive appraisal of the use of personalized models. Notably, there was no statistically significant improvement in overall knowledge scores; however, there was a discernible increase of 0.5 points in the ratings related to perceived expertise and procedural abilities. CONCLUSION: While there was a notable increase in the subjective ratings of knowledge and abilities, no statistically significant difference was observed between the two groups. The consensus among dental students is that individually planned and printed implant models serve as a valuable and effective tool in hands-on courses.

Approaching 3D printing in oral and maxillofacial surgery - suggestions for structured clinical standards.

PURPOSE: With respect to the European Union 2017 amendment of the Medical Device Regulations (MDR), this overview article presents recommendations concerning medical 3D printing in oral and maxillofacial surgery (OMFS). METHODS: The MDR were screened for applicability of the rules to medical in-house 3D printing. Applicable regulations were summarized and compared to the status of medical use of 3D printing in OMFS in Germany. Recommendations were made for MDR concerning medical 3D printing. RESULTS: In-house printed models, surgical guides, and implants fall under the category of Class I-III, depending on their invasive and active properties. In-house medical 3D printing for custom-made medical devices is possible under certain prerogatives: (1) the product is not being used in another facility, (2) appropriate quality systems are applied, (3) the reason for omitting commercial products is documented, (4) information about its use is supplied to the responsible authority, (5) there is a publicly accessible declaration of origin, identification, and conformity to the MDR, (6) there are records of manufacturing site, process and performance data, (7) all products are produced according to the requirements proclaimed before, and (8) there is an evaluation of clinical use and correction of possible issues. CONCLUSION: Several aspects must be addressed for in house medical 3D printing, according to the MDR. Devising MDR related to medical 3D printing is a growing challenge. The implementation of recommendations in OMFS could help practitioners to overcome the challenges and become aware of the in-house production and application of 3D printed devices.

Microvascular reconstructions in oral and maxillofacial surgery - Results of a survey among oral and maxillofacial surgeons in Germany, Austria, and Switzerland.

This study aimed to evaluate the use of microvascular free flaps (MFF) in oral and maxillofacial surgery (OMFS) in Germany, Austria, and Switzerland. A dynamic online questionnaire, using 42-46 questions, was sent to OMF surgeons based in hospitals in Germany, Austria, and Switzerland. The questionnaire was evaluated internally and externally. Aside from general information, data were collected on organizational aspects, approaches, MFF types and frequency, presurgical planning, intraoperative procedures, perioperative medications, flap monitoring, and patient management. Participants mostly performed 30-40 MFF each year (11/53). Most stated that the COVID-19 pandemic did influence MFF frequency (25/53) to varying extents. Radial forearm flap was most frequently used (37/53), followed by ALT (5/53), and fibula flap (5/53). Primary reconstruction was performed by most participants (35/48). Irradiated bony transplants were mostly used for implant placement after 12 months (23/48). Most participants (38/48) used reconstruction plates, followed by miniplates (36/48), PSI reconstruction (31/48), and PSI miniplates (10/48). Regarding the postoperative use of anticoagulants, low-molecular-weight (37/48) and unfractioned heparins (15/48) were widely used, most often for 3-7 days (26/48). Clinical evaluation was mostly preferred for flap monitoring (47/48), usually every 2 h (34/48), for at least 48 h (19/48). Strong heterogeneity in MFF reconstructions in OMFS was found, especially regarding the timepoints of reconstruction, types of osteosynthesis, and postoperative MFF management. These findings provide the chance to further compare the different treatment algorithms regarding relevant MFF aspects, such as postoperative management. This could create evidence-based treatment algorithms that will further improve the clinical outcomes in MFF reconstructions.

A survey regarding the organizational aspects and quality systems of in-house 3D printing in oral and maxillofacial surgery in Germany.

PURPOSE: The aim of the study was to get a cross-sectional overview of the current status of specific organizational procedures, quality control systems, and standard operating procedures for the use of three-dimensional (3D) printing to assist in-house workflow using additive manufacturing in oral and maxillofacial surgery (OMFS) in Germany. METHODS: An online questionnaire including dynamic components containing 16-29 questions regarding specific organizational aspects, process workflows, quality controls, documentation, and the respective backgrounds in 3D printing was sent to OMF surgeons in university and non-university hospitals as well as private practices with and without inpatient treatment facilities. Participants were recruited from a former study population regarding 3D printing; all participants owned a 3D printer and were registered with the German Association of Oral and Maxillofacial Surgery. RESULTS: Sixty-seven participants answered the questionnaires. Of those, 20 participants ran a 3D printer in-unit. Quality assurance measures were performed by 13 participants and underlying processes by 8 participants, respectively. Standard operating procedures regarding computer-aided design and manufacturing, post-processing, use, or storage of printed goods were non-existent in most printing units. Data segmentation as well as computer-aided design and manufacturing were conducted by a medical doctor in most cases (n = 19, n = 18, n = 8, respectively). Most participants (n = 8) stated that "medical device regulations did not have any influence yet, but an adaptation of the processes is planned for the future." CONCLUSION: The findings demonstrated significant differences in 3D printing management in OMFS, especially concerning process workflows, quality control, and documentation. Considering the ever-increasing regulations for medical devices, there might be a necessity for standardized 3D printing recommendations and regulations in OMFS.

An update on the current training situation of German interns in oral and maxillofacial surgery at special times in 2021.

The aim of this study was to evaluate the current state of training of German interns in oral and maxillofacial surgery (OMFS) under the influence of the COVID-19 pandemic in 2021. A previously tested questionnaire consisting of 53 questions was sent to interns in German OMFS (non-) university hospitals and private practices as an online survey. The questionnaire was adapted to current topics, such as the ongoing COVID-19 pandemic, aspects concerning nighttime and weekend services, overtime hours, surgical logbooks, benefits of academic degrees and support for scientific activities, part-time employment, parental leave and childcare. Next, results of questions from before the COVID-19 pandemic were re-evaluated. The COVID-19 pandemic influenced the clinical work (71.83%) and the current state of training (68.64%) in OMFS of most participants. Nighttime and weekend services are possible for employees in possession of only one degree (87.93% with a medical degree) in most hospitals. Not having one or both doctorate degrees was considered to be a disadvantage by 54.95%. In all, 42.11% of the participants attested to a positive influence of research on their training situation, and 50% reported financial or non-financial research support from the employer. Part-time employment was possible for 78.81% of the participants. The course of training was interrupted more often for women due to parental or maternity leave (10.53% of men and 30.95% of women). A total of 40.71% of the participants reported that childcare was available at the hospital, theoretically. The state of OMFS training in Germany can be referred to as positive. Current and future challenges are diverse, including aspects originating from the ongoing COVID-19 pandemic, gender aspects, reconciliation of family and work, and flexible working hours. Addressing these topics will ensure OMFS training at the highest surgical level and further increase interns' satisfaction, preserving the specialty's popularity and reception.

3D printing in oral and maxillofacial surgery: a nationwide survey among university and non-university hospitals and private practices in Germany.

OBJECTIVES: Oral and maxillofacial surgery (OMFS) has undergone pioneering progress through the development of three-dimensional (3D) printing technologies. The aim of this study was to evaluate the use of 3D printing at OMFS university and non-university hospitals and private practices in Germany. MATERIALS AND METHODS: For explorative assessment, a dynamic online questionnaire containing 10-22 questions about the current use of 3D printing and the reasons behind it was sent to OMFS university and non-university hospitals and private practices in Germany by the study group from the German Association of Oral and Maxillofacial Surgery (DGMKG). RESULTS: In total, 156 participants responded from university (23 [14.7%]) and non-university hospitals (19 [12.2%]) and private practices without (85 [50.5%]) and with 29 (18.6%) inpatient treatment facility. Highest applications of 3D printing were in implantology (57%), microvascular bone reconstructions (25.6%), and orthognathics (21.1%). Among the participants, 37.8% reportedly were not using 3D printing. Among the hospitals and private practices, 21.1% had their own 3D printer, and 2.5% shared it with other departments. The major reason for not having a 3D printer was poor cost efficiency (37.6%). Possessing a 3D printer was motivated by independence from external providers (91.3%) and rapid template production (82.6%). The preferred printing methods were stereolithography (69.4 %) and filament printing (44.4%). CONCLUSIONS: OMFS 3D printing is established in Germany with a wide range of applications. CLINICAL RELEVANCE: The prevalence of 3D printing in hospitals and private practices is moderate. This may be enhanced by future innovations including improved cost efficiency.

How is neck dissection performed in Oral and Maxillofacial Surgery? Results of a representative nationwide survey among university and non-university hospitals in Germany.

INTRODUCTION: Neck dissection (ND) is a surgical procedure addressing cervical lymph nodes and metastases in patients with oral squamous cell carcinoma (OSCC). The aim of this study was to analyze clinical decisions regarding indications and variations of ND in Oral and Maxillofacial Surgery (OMFS) in Germany. MATERIAL AND METHODS: A nationwide survey of the German Association of Oral and Maxillofacial Surgery was performed using dynamic online questionnaires including 38 questions. Data about oncological centers, case numbers, and staging procedures were collected. Relevant aspects, such as inclusion of level IIb and levels IV and V to ND, uni- vs. bilateral ND, and the influence of extra-nodal extension (ENE) of metastases on extension of ND were evaluated. RESULTS: Eighty-four OMFS of university and non-university hospitals participated in the study (responding rate 21.4%). Sixty-six (78.57%) stated to work at certified cancer centers and 53.57% of the hospitals treated between 50 and 100 OSCC cases per year. CT and/or MRI of the head and neck was performed in most of the staging procedures. Level IIb was included by 71 (93.42%) of the participants in selective ND. Levels IV and V were included by 53 (69.74%) in node-positive neck. In solitary ipsilateral metastases (ENE-), 49 participants (62.82%) stated to perform exclusively an ipsilateral ND and 40 (51.95%) stated to perform only an ipsilateral ND in ENE+. CONCLUSION: This study demonstrated a high rate of certified cancer centers in Germany showing differences regarding staging procedures, indications, and extension of ND, especially in increasingly complex cases. CLINICAL RELEVANCE: Clinical decisions regarding ND are dependent on case-individual aspects and must be decided individually.

Identification of cutaneous perforators for microvascular surgery using hyperspectral technique - A feasibility study on the antero-lateral thigh.

Aim of the study was to compare perforator vessel location using color-coded Doppler ultrasound and hyperspectral imaging in the area of the antero-lateral thigh. In a cross-sectional case-control study, the bilateral antero-lateral thigh region was examined for perforator vessel location via color-coded Doppler ultrasound (control) and hyperspectral imaging (test). For hyperspectral imaging, all measurements were conducted without cooling (T0) and after 1 (T1), 2 (T2) and 3 min (T3) of cooling. Additionally, in the reperfusion period after cooling, hyperspectral imaging was conducted at 1, 2 and 3 min (T4/T5/T6). Results from color-coded Doppler ultrasound and hyperspectral imaging were matched at all time points (T0-T6). In total, 71/73 perforator vessel locations could be matched (sensitivity: 97%). Matching of color-coded Doppler ultrasound and hyperspectral imaging was significantly influenced by the cooling protocol and the highest matching values were seen at T3 (3 min cooling; 60 perforator vessels) and T4 (3 min cooling & 1 min reperfusion; 62 perforator vessels) without significant differences (sensitivity 98%; p = 0.9). There were significant differences between T4 and T0, T1 (both p < 0.001), T5 (p = 0.045) and T6 (p = 0.012). For clinical proof of concept, a patient case using a free antero-lateral thigh flap for reconstruction of a facial defect after perforator vessel identification via color-coded Doppler ultrasound and hyperspectral imaging (3 min cooling & 1 min reperfusion) was carried out successfully. In conclusion, hyperspectral imaging potentially offers an additional opportunity for non-invasive, user-independent perforator-site assessment if prior cooling of the site is conducted.

Implant primary stability depending on protocol and insertion mode - an ex vivo study.

BACKGROUND: Dental implant primary stability is thought to be a fundamental prerequisite for the long-term survival and success. The aim of this study was to analyze the influence of protocol and insertion mode on dental implant stability ex vivo. One hundred and twenty implants were inserted either manually or machine-driven into porcine mandibles by a standard or over-dimensioned protocol. Dental implant stability was measured via resonance frequency analysis (RFA), insertion torque (IT), and torque out (TO). RESULTS: Statistically significant higher IT and TO values were seen after standard protocol insertion (p < 0.05), whereas manual and machine-driven insertion mode showed equivalent values. CONCLUSIONS: The over-dimensioned protocol exceeded the primary stability values recommended for immediate implant insertion; therefore, it could be recommended as well.

Integration of Perforator Vessels in CAD/CAM Free Fibula Graft Planning: A Clinical Feasibility Study.

INTRODUCTION: Commercial CAD/CAM planning of free osteocutaneous microvascular fibula flap does not support integration of soft tissue structures including perforator vessel anatomy. Therefore, in a clinical trial, a method for such a combined hard- and soft tissue 3D-fibula planning was assessed. MATERIALS AND METHODS: In a clinical study on 24 patients needing reconstruction with osteocutaneous fibula graft, skin perforators of the respective leg were detected via Doppler sonography and documented on a measurement device. Each of the perforators' localization was transferred to a CAD/CAM planning software and included in each planning step as well as in the surgical cutting guide. A comparison between sonography and clinical localization, damage to perforator vessels during surgery as well as a subjective evaluation of feasibility and usefulness of the procedure was carried out. RESULTS: In total, 19 skin paddles were placed orally, 2 extraorally and 3 at both sites at once. Survival rate was 92% (22/24). In addition, 3 skin paddles were lost complete and 2 partially. Anatomical sites of perforator vessels were never < 1 cm from planned positions and not damaged at all (n = 75). Planning was judged useful for skin paddle design and positioning of osteotomies. In accordance, surgical guides were always implemented successfully without the need of changing planned procedures during surgery. CONCLUSION: Integration of skin perforators into 3D planning of microvascular fibular graft is feasible and may even decrease involuntary dissection of perforator vessels. Even so, clinical studies for comparison are needed.

The risk of tooth root injuries using cortical screws for intermaxillary fixation and osteosynthesis plates - A retrospective analysis.

Intermaxillary fixation (IMF) and osteosynthesis plates (OP) are widely used for the non-surgical and surgical treatment of mandible and condyle fractures. The aim of this retrospective study was to analyze the frequency of tooth root injuries by IMF and OP screws. Electronic patient reports (2004-2013) were screened for patients treated with either IMF screws and/or OP in the Department of Oral- and Maxillofacial Surgery, University Medical Center Mainz, Germany. The frequency and the position of endangered and injured teeth were analyzed by orthopantomogram (OPTG) and cone beam computer tomography (CBCT). Next, possible predictive factors for tooth root injuries, namely interdental- and crestal distance, screw length and distance between tooth root and screw were evaluated. Further, the accuracy of OPTG vs. CBCT concerning the diagnosis of tooth root injuries was analyzed. Three-hundred sixty-six patients were included and 3388 teeth were defined as endangered by IMF- and OP screws. Overall, 16 injured teeth (0.5%) in 13 patients (3.55%) were detected. Nine injuries (56.3%) were caused by IMF- and seven injuries (43.8%) by OP screws. Three teeth were non-vital, one tooth had to be extracted. No correlation between the predictive factors crestal distance, screw length and tooth root injuries was found. If tooth injury occurred, a significant correlation between the interdental distance and the distance between tooth root and screw was found (κ = 0.48; p < 0,0001). Comparison between OPTG vs. CBCT demonstrated that many of the injuries that were seen in the OPTG (n = 230) could not be verified in the CBCT scans (n = 16) (κ = 0.12). To conclude, screws for IMF and OP can be considered as a safe procedure concerning the risk of tooth root injuries.

Safety of resection margins in CAD/CAM-guided primarily reconstructed oral squamous cell carcinoma-a retrospective case series.

OBJECTIVES: After resection of malignancies of the jaws, CAD/CAM procedures have become standard for primary bony reconstruction. Even so, these techniques may limit surgical resection safety. Therefore, the aim of the study was to examine osseous as well as soft tissue resection margins after CAD/CAM-guided tumor resections and reconstructions. METHODS: A retrospective analysis of patients treated with oral squamous cell carcinoma (OSCC) from 2014 to 2019 was performed. Inclusion criteria were CAD/CAM-guided osseous resection and primary reconstruction. Evaluation was performed for histological confirmed resection margins (hard and soft tissue) as well as recurrence of the disease related to the resection status. RESULTS: In 46 patients, bony resection margins were classified: tumor free (R0 41/46), microscopical invasion (R1 1/46), and close margin (R0 < 4 mm 4/46) respectively for soft tissue 29/46 tumor free (R0), 7/46 close margin (R0 < 4 mm), 5/46 R1, and 4/46 could not be further determined (Rx). Fourteen patients (14/46) showed recurrent disease (2/46 locoregional) without association with the bony resection margin status. Recurrence occurred predominantly (13/46) in high-staged tumor patients. R1/close margin/Rx resection of the soft tissue resulted in a significant earlier recurrence when compared with R0 resection. CONCLUSION: CAD/CAM procedure allows safe tumor resection with the profit of a guided and accurate reconstruction. In contrast to positive soft tissue margins, positive bony resection margins did not increase recurrence parameters.

Leech related Aeromonas veronii complex infection after reconstruction with a microvascular forearm flap.

Medical leeches (Hirudo medicinalis) in plastic and reconstructive surgery are often used for the treatment of vascular failure after microvascular surgery. Leeches are a reservoir for bacteria of the Aeromonas group that help digesting the blood meal. In some cases these bacteria are able to cause severe wound infections that can lead to loss of tissue transplants. We report about a patient with a common microvascular forearm flap after resection of an oral squamous cell carcinoma which got infected by Aeromonas spp. after treatment with medical leeches. Most of these species are resistant for common antibiotic treatment after surgery. This report shows the importance of an early concomitant antibiotic prophylaxis in the treatment of venous congestion with medical leeches.

Self-drilling and self-tapping miniscrews for osteosynthesis fixture after LeFort I osteotomy: An ex vivo trial for primary stability and a randomized clinical study.

BACKGROUND: Self-drilling osteosynthesis screws (SDS) have a potential higher primary stability together with clinical advantages such as less time effort compared to self-tapping screws (STS). The aims of the study were to compare the primary stability of SDS and STS ex vivo and to analyze of the time-saving effect in vivo. MATERIALS AND METHODS: Ex vivo, both screws were placed in porcine bone. Torque was measured for insertion and removal. Four specimens were kept in bone for histologic bone-to-implant-contact examination. In vivo, 49 patients who received orthognathic surgery in the maxilla were included in 2 centers. In a split-mouth design, the time for osteosynthesis fixation and perioperative events were recorded. RESULTS: Ex vivo, insertion and removal torque measurements were higher for SDS, especially in dense bone. Histologic imaging on the exemplary-stained specimens showed higher bone contact and compressed bone matrix for SDS in all bone densities. In vivo, the mean osteosynthesis time in both centers was 5.5 min (±3.03) for SDS and 5.5 min (±2.37) for STS. Separate analysis showed that center I was faster with STS and center II with SDS. Although, in center I a higher rate of failed primary stability of SDS compared to STS was documented. CONCLUSIONS: SDS showed a partially higher primary stability ex vivo, especially in dense bone. The timesaving effect of SDS is less pronounced than expected, but technically SDS might be favorable where drilling is difficult or even impossible.

Biomarkers in diagnosis and therapy of oral squamous cell carcinoma: A review of the literature.

Oral squamous cell carcinoma (OSCC) represents the sixth most common cancer, accounting for 2-4% of all malignancies worldwide. The overall survival rate of less than 60% remains generally poor, with prognosis heavily relying on the TNM staging system. Tumor size as well as the presence and extent of lymph node metastases are widely recognized as the most important predictors. However, the underlying mechanisms that lead to an aggressive phenotype are not yet fully understood. Therefore, possible biomarkers are much in need to predict prognosis, to help individualize therapy approaches, and to overcome possible resistance mechanisms. Despite a multitude of recently published biomarkers for OSCC, there is still an ongoing debate regarding their implementation in the clinical workflow. Thus, a systematic literature search via PubMed was performed to update the current literature with the latest evidence. In total, 128 studies were included and over 100 different biomarkers evaluated with reference to their influence of survival, tumor recurrence, advanced grading and lymph node metastasis. In this review, we highlight the important molecular mechanism underlying possible markers in tissue, blood or saliva samples for OSCC. As a major result, no clinical trials could be obtained to prove clinical importance of the validated predictors for survival, tumor recurrence, lymph node metastasis and therapy resistance. Therefore, further clinical investigations are much needed.

Accelerated workflow for primary jaw reconstruction with microvascular fibula graft.

INTRODUCTION: Major facial defects due to cancer or deformities can be reconstructed through microvascular osteocutaneous flaps. Hereby CAD/CAM workflows offer a possibility to optimize reconstruct and reduce surgical time. We present a retrospectiv observational study regarding the developement of an in-house workflow allowing an accelerated CAD/CAM fibula reconstruction without outsourcing. CASE DESCRIPTION: Workflow includes data acquisition through computertomography of head and legs, segmentation of the data and virtual surgery. The virtual surgery was transferred into surgical guides and prebent osteosynthesis plate. Those were sterilized and used in surgery. EVALUATION: The workflow was used in 30 cases. Minimum planning period took 4 days from CT to surgery, average time was 8 days. Planning could be transferred to surgery every time. Intraoperative complications regarding osteotomy, assembly and fixation did not occur. DISCUSSION/CONCLUSION: An in-house workflow for CAD/CAM fibula reconstruction is feasible within a few days providing an accelerated procedure even in urgent cases.

Applications of patient-specific 3D printing in medicine.

Already three decades ago, the potential of medical 3D printing (3DP) or rapid prototyping for improved patient treatment began to be recognized. Since then, more and more medical indications in different surgical disciplines have been improved by using this new technique. Numerous examples have demonstrated the enormous benefit of 3DP in the medical care of patients by, for example, planning complex surgical interventions preoperatively, reducing implantation steps and anesthesia times, and helping with intraoperative orientation. At the beginning of every individual 3D model, patient-specific data on the basis of computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound data is generated, which is then digitalized and processed using computer-aided design/computer-aided manufacturing (CAD/CAM) software. Finally, the resulting data sets are used to generate 3D-printed models or even implants. There are a variety of different application areas in the various medical fields, eg, drill or positioning templates, or surgical guides in maxillofacial surgery, or patient-specific implants in orthopedics. Furthermore, in vascular surgery it is possible to visualize pathologies such as aortic aneurysms so as to improve the planning of surgical treatment. Although rapid prototyping of individual models and implants is already applied very successfully in regenerative medicine, most of the materials used for 3DP are not yet suitable for implantation in the body. Therefore, it will be necessary in future to develop novel therapy approaches and design new materials in order to completely reconstruct natural tissue.

Materials and scaffolds in medical 3D printing and bioprinting in the context of bone regeneration.

The structural and functional repair of lost bone is still one of the biggest challenges in regenerative medicine. In many cases, autologous bone is used for the reconstruction of bone tissue; however, the availability of autologous material is limited, which always means additional stress to the patient. Due to this, more and more frequently various biocompatible materials are being used instead for bone augmentation. In this context, in order to ensure the structural function of the bone, scaffolds are implanted and fixed into the bone defect, depending on the medical indication. Nevertheless, for the surgeon, every individual clinical condition in which standardized scaffolds have to be aligned is challenging, and in many cases the alignment is not possible without limitations. Therefore, in the last decades, 3D printing (3DP) or additive manufacturing (AM) of scaffolds has become one of the most innovative approaches in surgery to individualize and improve the treatment of patients. Numerous biocompatible materials are available for 3DP, and various printing techniques can be applied, depending on the process conditions of these materials. Besides these conventional printing techniques, another promising approach in the context of medical AM is 3D bioprinting, a technique which makes it possible to print human cells embedded in special carrier substances to generate functional tissues. Even the direct printing into bone defects or lesions becomes possible. 3DP is already improving the treatment of patients, and has the potential to revolutionize regenerative medicine in future.