Goldenhar Syndrome: Quality-of-Life Analysis of 43 Consecutive Patients.

Goldenhar syndrome is a rare congenital disease, characterized by the malformation of craniofacial features, spine, and other organs. Its pathogenesis and impact on patients' quality of life (QoL) have not been fully elucidated as yet. Therefore, data of all patients with Goldenhar syndrome, who were treated at Hannover Medical School between 1997 and 2020, were analyzed. Forty-three patients were identified. Their medical records were carefully reviewed for data regarding their age, sex, demographics, Pruzansky classification, surgical history, and affected side. Goldenhar syndrome-associated medical conditions, therapeutic procedures, and the impact of disease on QoL were assessed. Their QoL was assessed using the Oral Health Impact Profile (OHIP)-14 questionnaire. The χ 2 test and Pearson correlation were performed for statistical evaluation. Female sex was positively correlated with OHIP outcomes, whereas male sex had a negative correlation with OHIP outcomes. Therefore, females had significantly worse QoL than males. No significant correlation was observed between the Pruzansky classification and QoL or between surgical history and QoL. Goldenhar syndrome is a rare disease that presents with varying severity. Hence, prospective studies are required to further investigate the impact of Goldenhar syndrome on the QoL.

Gender-specific differences concerning psychosocial aspects and functional impairments that influence quality of life in oral cancer treatment.

PURPOSE: Patients with oral cancer have gender-specific differences with respect to health-related quality of life (HRQoL) and psychosocial variables (PV). The aim of the present study was to evaluate HRQoL and PV outcomes in patients treated for oral squamous cell carcinoma. METHODS: Data of 1234 patients were collected from a multicenter rehabilitation study of the German-Austrian-Swiss Cooperative Group on Tumours of the Maxillofacial Region (DÖSAK). Patient characteristics, oncological variables, post-treatment impairments, general quality of life (QoL), and PV (coping strategies, control beliefs, personal traits, perceived social support, depression, anxiety, and fear of tumor recurrence) were recorded. RESULTS: After treatment, HRQoL was similar between genders concerning general QoL, but men experienced significantly more treatment-related functional impairments influencing HRQoL. PV revealed gender-specific coping strategies, with women reporting significantly more "depressive coping," "religiosity," "fatalistic externality," and higher "social burden." Owing to their religious coping strategies, fatalistic attitude, and perceived higher social integration, women demonstrated superior disease acceptance, despite higher depression, anxiety, and lower psychosocial resilience. Conversely, men reported more introverted personal traits and lower social integration. CONCLUSION: Interventions during oral cancer treatment should address PV and have gender-specific elements to improve HRQoL after therapy.

Pitfalls of Surgeon-Engineer Communication and the Effect of In-House Engineer Training During Digital Planning of Patient-Specific Implants for Orbital Reconstruction.

PURPOSE: The use of patient-specific implants for reconstruction of complex orbital floor defects is increasing and requires communication with an industry partner, which warrants investigation. Therefore, the aim of this study was to evaluate the effects of in-house training of engineers on such communication as well as to identify frequent sources of problems and their solutions for improvement of the implant-planning workflow. METHODS: We conducted a retrospective cross-sectional study and enrolled a sample of patients who had undergone orbital reconstruction with patient-specific implants between 2017 and 2020. The predictor variables were in-house training (additional training completed in hospital or not) and implant complexity (complex [multiwalled implants] vs less complex [isolated orbital floor reconstructions]). The outcome variables were duration of communication, message length, and need for synchronous communication or modifications to the original design. Descriptive, univariate, and multivariate statistics were computed, and statistical significance was set at a P value of < 0.05. RESULTS: This study included the data of 66 patients (48 men and 18 women, average age: 42.27 years). The complexity of the implant statistically significantly increased the duration of the communication (8.76 vs 16.03 days; P = .004). In 72.73%, the initial design had to be changed. Engineers trained in house required less communication to plan less-complex implants and generally needed fewer corrections to the original design (P = .020 and P = .036, respectively). Problems during planning were observed in 25.76% of the cases, with an insufficient diagnostic 3-dimensional data set being the most common (15.15%). CONCLUSIONS: In-house training of engineers is time-saving while planning the workflow for patient-specific implants, especially in less-complex cases, given that design changes are not needed often. The high rate of data sets that were insufficient for planning patient-specific implants suggests that diagnostic 3-dimensional data sets should already meet the requirements for such planning.

Prelamination of the Radial Forearm Free Flap Using Free Full-Thickness Eyelid Skin Grafts: A New Approach for Intraoral Defect Reconstruction.

ABSTRACT: Free flap transfer for reconstruction of intraoral defects is a common procedure in oral and maxillofacial surgery. For tumor-related defects, the radial forearm flap is widely used for soft tissue restoration. However, transfer of free skin grafts to the donor site region is often required for wound closure after free flap harvesting, resulting in esthetic disturbances due to shrinkage of the grafted skin, attendant scarring, or mismatches in skin texture or color. Furthermore, free flap transfer may result in hair follicle transfer into the oral cavity, causing unfavorable intraoral hair growth in adult men in particular. Free flap prelamination can help reduce the potential disadvantages of free flaps, in terms of both flap design and size and donor site morbidity. For surgical treatment of oral cancer in middle-aged and elderly patients, eyelid dermatochalasis may present as a comorbidity leading to esthetic impairments or, in cases involving the upper eyelid, even a reduced field of view. In these cases, bilateral blepharoplasty can reduce the excess eyelid skin. The present study is the first to attempt to use excised skin after bilateral blepharoplasty as full-thickness skin grafts for radial forearm free flap prelamination. This approach combined surgical therapy of eyelid dermatochalasis with free flap prelamination, thereby avoiding the need to harvest free skin grafts from other anatomically healthy regions to close the donor site defect and preventing the accompanying disadvantages. The reconstruction results and clinical outcomes of patients revealed that radial forearm free flap prelamination using bilateral free full-thickness eyelid skin grafts was an easy and feasible method for intraoral defect reconstruction. In particular, this approach could avoid intraoral hair growth and additional skin grafting from other healthy anatomical regions, yielding good esthetic and functional results at the flap's recipient and donor sites.

[Optic nerve decompression-state of the art]. / Optikusdekompressionen ­ Stand der Technik.

Rarely, but often with serious consequences for the patient, the optic nerve is affected during the course of head injuries. Traumatic optic nerve compression is always an emergency situation, which is why time is of the essence for both diagnosis and treatment. Precise knowledge of this accident sequelae but also of the resulting conditions, especially in terms of traumatic optic neuropathy, is indispensable for adequate patient care. The aim of this paper is to provide an overview of this clinical picture, particularly with regard to etiology, diagnosis, and treatment options, and to discuss this in the context of the current literature.

Outcome and Quality of Life after Individual Computer-AssistedReconstruction of the Midface. / Ergebnisse und Lebensqualität nach individueller computer-gestützter Rekonstruktion des Mittelgesichtes.

Often, midfacial defects are not only relevant regarding functional aspects but also esthetics of such congenital or acquired deformities impair significantly the patients' quality of life. Reconstructions of the midface do not only include replacing lost or non-developed tissue but moreover to achieve predictable results with regard to esthetics as well as function for the individual patient. Digital planning modalities including different surface and volume data in combination with modern additive manufacturing techniques for biomodel and implant production and intraoperative support by using real and virtual 3D volume data for navigation and intraoperative imaging, but also securing the outcome based on postoperative analysis have been implemented in modern midface reconstruction and represent new standards for medical care. The objective of this paper is to describe modern options of patient-specific midfacial reconstruction with integration of computer-assisted planning and production techniques.

Fulfillment of patients' information needs during oral cancer treatment and its association with posttherapeutic quality of life.

PURPOSE: Surgical therapy for oral cancer can lead to severe physical and psychological disorders that negatively impact patient quality of life (QoL). This study aimed to evaluate the relationship between fulfillment of patients' information needs during oral cancer treatment and patients' perception of posttherapeutic disorders influencing QoL. METHODS: A retrospective analysis of 1359 patients who were surgically treated for oral cancer using questionnaires administered during the multicenter rehabilitation study by the German-Austrian-Swiss Cooperative Group on Tumors of the Maxillofacial Region (DÖSAK). Patients and medical practitioners completed questionnaires following cancer treatment. RESULTS: Approximately 37% of patients felt inadequately informed about possible physical and psychological consequences of surgery. In contrast, only 16% of patients felt they were given inadequate information about the operative procedure and possible complications, and with regard to tumor diagnosis and cancer disease, only 15% of patients. Significant correlations were found between lacking information and increased perception of posttherapeutic disorders, whereas correlations with tumor-specific and operation-related parameters were markedly lower. The patients with superior QoL after treatment stated more frequently, nearly independent of individual patient characteristics, that the information that they were given prior to therapy was adequate. Information concerning possible physical and psychological consequences of an operation, however, was frequently stated to be inadequate, independent of QoL. CONCLUSION: Patients whose information needs concerning the diagnosis and treatment of oral cancer are adequately fulfilled may benefit in terms of their therapeutic outcome, experiencing less perception of posttherapeutic physical and psychological disorders and a superior QoL.

Changes in Emergency Patient Presentation to a Maxillofacial Surgery Department During the COVID-19 Pandemic.

PURPOSE: To examine possible changes in the emergency patient volume and reasons for presentation to an oral and maxillofacial surgery department during the coronavirus disease 2019 (COVID-19) pandemic and the resulting contact prohibitions. We hypothesized that the pandemic would lead to fewer patients presenting with emergent conditions. METHODS: A total of 939 patients, who presented to the Department for Oral and Maxillofacial Surgery of Hannover Medical School during the first 4 weeks of contact prohibitions in Germany, starting from March 23, 2020 until April 19, 2020, and in comparable periods were examined. The number of patients, reason for presentation, and required treatments were documented and compared to the years 2018 and 2019. Special attention was paid to the changes in trauma cases. RESULTS: We found that the number of patients in 2020 was significantly lower (P(2019) < .001, P(2018) < .01), but sex and age distributions were comparable to those in the previous years. Both the absolute and relative frequencies of dental diagnoses were significantly lower in 2020 (P(2019) < .001, P(2018) < .001), while the proportion of patients who presented with trauma was significantly higher (P(2019) < .001, P(2018) < .001). A significant decrease in patient number to the hospital, despite private practices being closed, was presumably due to patients' infection-related concerns. Trauma cases were more frequent in private settings, and traumatic events under the influence of alcohol were frequent. The circumstances and not the absolute number of trauma events had changed. CONCLUSIONS: The results of this study suggest that the COVID-19 pandemic has important effects on the use of emergency services concerning oral and maxillofacial surgery in Germany.

[Complex reconstructions in the facial and cranial regions]. / Komplexe Rekonstruktionen im Gesichts- und im Schädelbereich.

Posttraumatic reconstruction of the neurocranium and viscerocranium is an essential part of modern oral and maxillofacial surgery, in addition to oncological surgery, surgery of congenital craniofacial deformities and dental surgery. Due to the complex anatomy of the facial skull and significant esthetic and functional demands on its reconstruction, reconstructive trauma surgery in this area places the highest demands on the surgeon. This is all the more true if definitive craniomaxillofacial surgical treatment can sometimes only be performed with considerable delays for the benefit of other life-threatening injuries. In order to take these prerequisites into account, achievements of modern biomedical technology, such as intraoperative real-time navigation, computer-assisted planning and computer-assisted manufacturing (CAD/CAM) of patient-specific biomodels and implants, came up early for use in oral and maxillofacial surgery. In combination with intraoperative three-dimensional imaging, these methods result in a treatment pathway tailored to the individual patient, which is directly checked for quality at every step and thus ensures the best possible result for the patient. The use of these technologies extends far beyond the original indications in the area of orbital reconstruction and restoration of bony defects with simple geometry, such as skull defects. Nowadays, even the most complex pan-facial fractures can be restored esthetically and functionally by means of digitalized preliminary planning and individualized skull, orbital and zygomatic implants as well as total temporomandibular joint prostheses.

A Novel Method for Secondary Mandible Reconstruction to Re-Achieve a Native Condyle Position Comprising a New Design for Cutting Guides and New Positioning Devices.

Secondary mandibular reconstruction using fibular free flaps (FFF) is a technical challenge for surgeons. Appropriate operation planning is crucial for postoperative quality control and is notably necessary for the (re-) achievement of a physiological condylar position, and the sensible expansion and shaping of the transplant. Computer-assisted planning may help to reconstruct mandibular defects in a patient-specific and precise manner. Herein, we present a newly-developed workflow for secondary mandibular reconstruction using FFF; it comprises digital planning and in-house manufacturing to perform precise secondary mandible reconstruction. This method utilizes a newly designed positioning device to ensure the precise positioning of the fibula segments in relation to each other and the mandibular stumps. The presented in-house-printed positioning device made it possible to achieve digital planning with high precision during surgery.

Exceptional Cases Demand Exceptional Personalized Solutions: The Next Level in Dental Rehabilitation.

Defects and bone loss in the maxilla and mandible pose significant challenges for dental rehabilitation. This paper focuses on complex cases of bimaxillary dental rehabilitation, where traditional dental implant protocols were not feasible in at least one jaw. Four patients were examined conceptually, where conventional dental implant placement (n = 20) was combined in either the same or opposite jaw with a patient-specific subperiosteal implant (n = 5). This study evaluates aspects such as primary stability, prosthodontic restoration, complications, and soft tissue management over the observation period. None of the five patient-specific subperiosteal implants (IPS Implants® Preprosthetic; KLS-Martin Group, Tuttlingen, Germany) experienced failure or showed any loosening of screws, with the longest observation period extending to 68 months. These implants were securely fixated away from the posts, without any biomechanical restrictions on loading from the time of insertion. Planning and manufacturing, including the initial suprastructure, followed a fully digital workflow. The number of screws required for multivector fixation ranged from 13 to 22. All dental implants placed remain functional, definitive prosthodontic restoration has been performed, and no stability loss or peri-implantitis has been observed. The IPS Implants® Preprosthetic emerges as a valuable consideration when conventional implant dentistry protocols encounter limitations.

Dental rehabilitation in irradiated oral cancer patients using patient-specific dental implants - Clinical outcome and oral health-related quality of life.

INTRODUCTION: Dental rehabilitation in oral cancer patients is essential for good oral health-related quality of life (OHRQoL). Patient-specific dental implants are suitable for treating tumor-related bony defects, resulting in satisfactory OHRQoL. However, knowledge concerning the clinical outcome and OHRQoL following tumor irradiation is lacking. MATERIAL AND METHODS: A retrospective analysis was carried out to evaluate clinical outcomes and OHRQoL in eight patients who received patient-specific dental implants and implant-supported dentures after surgical treatment for oral cancer with additional irradiation. OHRQoL assessment was performed using the German long version of the oral health impact profile (OHIP) questionnaire (OHIP-G53). RESULTS: Clinical examination revealed successful dental rehabilitation in all the patients with only minor impairments. Restricted stability and function of implants were not observed. OHIP sum-scores of all the patients indicated acceptable OHRQoL, but this varied between patients treated in the upper or lower jaw. Single-item sum-scores concerning the adverse events "difficulty in chewing," "food catching," "sore jaw," "sore spots," and "unclear speech" were detected to be the worst, and pain-related OHIP dimensions demonstrated the highest scores (followed by functional limitation, physical disability, and psychosocial impact) with a worse OHRQoL following lower jaw treatment. Other dimension sum-scores were overall lower and nearly equally distributed in patients. CONCLUSIONS: Dental rehabilitation of irradiated oral cancer patients using patient-specific dental implants may be suitable, leading to acceptable OHRQoL. However, implant insertion in the upper jaw seems to be more favorable. Further studies on patient-specific dental implants are warranted to validate the current results.

Functional features of cancer stem cells in melanoma cell lines.

BACKGROUND: Recent evidence suggests a subset of cells within a tumor with "stem-like" characteristics. These cells are able to transplant tumors in immunodeficient hosts. Distinct from non-malignant stem cells, cancer stem cells (CSC) show low proliferative rates, high self-renewing capacity, propensity to differentiate into actively proliferating tumor cells, and resistance to chemotherapy or radiation. They are often characterized by elevated expression of stem cell surface markers, in particular CD133, and sets of differentially expressed stem cell-associated genes. CSC are usually rare in clinical specimens and hardly amenable to functional studies and gene expression profiling. In this study, a panel of heterogenous melanoma cell lines was screened for typical CSC features. METHODS: Nine heterogeneous metastatic melanoma cell lines including D10 and WM115 were studied. Cell lines were phenotyped using flow cytometry and clonogenic assays were performed by limiting dilution analysis on magnetically sorted cells. Spheroidal growth was investigated in pretreated flasks. Gene expression profiles were assessed by using real-time rt-PCR and DNA microarrays. Magnetically sorted tumor cells were subcutaneously injected into the flanks of immunodeficient mice. Comparative immunohistochemistry was performed on xenografts and primary human melanoma sections. RESULTS: D10 cells expressed CD133 with a significantly higher clonogenic capacity as compared to CD133- cells. Na8, D10, and HBL cells formed spheroids on poly-HEMA-coated flasks. D10, Me39, RE, and WM115 cells expressed at least 2 of the 3 regulatory core transcription factors SOX2, NANOG, and OCT4 involved in the maintenance of stemness in mesenchymal stem cells. Gene expression profiling on CD133+ and CD133- D10 cells revealed 68 up- and 47 downregulated genes (+/-1.3 fold). Two genes, MGP and PROM1 (CD133), were outstandingly upregulated. CD133+ D10 cells formed tumors in NSG mice contrary to CD133- cells and CD133 expression was detected in xenografts and primary human melanoma sections using immunohistochemistry. CONCLUSIONS: Established melanoma cell lines exhibit, to variable extents, the typical features of CSCs. The tumorigenic cell line D10, expressing CD133 and growing in spheroids and might qualify as a potential model of melanoma CSCs.

Patient-specific implants for reconstruction of orbit and skull following resection of spheno-orbital meningiomas: A two-implant concept.

INTRODUCTION: The surgical treatment of spheno-orbital meningioma (SOM) is challenging. In addition to anatomical constraints that lead to a difficult resection, the reconstruction of the resulting defect is demanding. Uniform recommendations concerning the best reconstruction technique are not available in the existing literature. We propose a novel two-piece concept for reconstructing post-ablative defects using patient-specific implants. MATERIAL AND METHODS: Between 2018 and 2021, seven patients underwent SOM resection using two digitally planned patient-specific implants for orbit and skull reconstruction. To analyze the accuracy of the reconstruction, preoperative plans were merged with postoperative data sets. The clinical outcome was evaluated by comparing the pre- and postoperative exophthalmos index (EI). RESULTS: In all cases, adequate reconstruction and a satisfactory match between the final implant position and preoperative planning were achieved. The EI was reduced in all cases from a mean of 1.27 to 1.09 (p = 0.003). CONCLUSIONS: The proposed concept of a two-piece reconstruction after SOM resection is an excellent way to manage the concern around post-ablative defects. The current technical conditions allow for a precise, safe, and predictable reconstruction.

Computer-assisted orbital and midfacial reconstruction.

Objective: Computer assistance has become indispensable in the reconstruction of the orbit and midface. Although these are key areas of an individual's esthetic appearance, defects or deformities of the midface, especially those of the orbit, are treated diversely. Methods: The aim of this article is to present the wide utility of computer-assistance in modern craniomaxillofacial surgery, including virtual planning, computer-aided design, guided surgery, navigational control, patient-specific implants, and quality control via image fusion. Results: There have been rapid advances in both digital planning and manufacturing processes, with continual improvements. Conclusions: Patient-specific implants have pushed the boundaries of reconstructive surgery in all surgical specialties.

Novel approach for treating challenging implant-borne maxillary dental rehabilitation cases of cleft lip and palate: a retrospective study.

PURPOSE: Dental restoration in cleft lip and palate (CLP) patients is demanding and often results in bone loss and dental implant failure. Furthermore, unfavorable conditions of hard and soft tissues as well as skeletal deformities aggravate surgical and dental treatment. Therefore, this study was designed to assess the feasibility of using a new type of patient-specific implant (IPS-preprosthetic®) in CLP patients. METHODS: Of the 63 patients who received a IPS-preprosthetic® implant in the Department of Oral and Maxillofacial Surgery at the Hannover Medical School, Germany, six patients were treated for a CLP deformity with significant soft and hard tissue impairment. Two patients were partially edentulous, whereas four patients were edentulous for the maxilla. All implants were inserted in a single-step outpatient surgery and were followed up for up to 40 months. RESULTS: Within the observation period, no implant failed and no screw loosening or change in stability of the implant to recipient site occurred (mean number of screws: 21). This study demonstrates, for the first time, the efficient use of a one-piece multivector screw primarily retained a stable patient-specific implant for implant-borne prosthodontic rehabilitation of CLP patients with deformities and challenging initial situations. CONCLUSIONS: IPS-preprosthetic® implants offer a novel approach to implant dentistry treatment protocols, especially in difficult cases of unusual anatomy, even when previous conventional treatment fails.

Time is crucial in malignant tumor cases: Speeding up the process of patient-specific implant creation.

Purpose: Patient-specific implants are commonly used to reconstruct lower jaw defects following surgical treatment for head and neck squamous cell carcinoma. The planning process of surgery is time-consuming and can delay the "time to surgery," which should be as short as possible. Therefore, this study aimed to evaluate the planning process to speed up and identify any sources of problems. Patients and methods: In this retrospective study, we enrolled patients who underwent continuous resection of the mandible in combination with reconstruction with a patient-specific implant between 2016 and 2021. The predictor variables were in-house training of the engineers and implant complexity (complex [with additional features] vs. less complex [resembling standard reconstruction plates]). The outcome variables were the duration of communication, message length, and the need for synchronous communication or modifications to the original design. Descriptive and univariate statistics were computed, and statistical significance was set at P < 0.05. Results: The data from 83 patients were included in this study. The mean duration of communication was 14.05 ± 13.58 days. The implant complexity and training status of the engineer had no statistically significant influence on the primary outcome variables. As for the secondary outcome variables, the implant complexity significantly influenced the chance that the planned operation had to be postponed (15/16 [93.75%] were complex cases, P = 0.001). The most frequent cause of problems in the planning process was an insufficient dataset, which was not dependent on the type of imaging. Conclusions: The overall duration of the patient-specific implant creation process is too long to meet oncological requirements. Therefore, standardization of the planning process to accelerate implant creation is of utmost importance. In addition, a common standard imaging format (independent of the type of imaging) for oncological cases could eliminate all delays caused by insufficient datasets in the future.

Evaluation of the Neuroprotective Effects of Methylprednisolone and Surgical Decompression in a Rodent Model of Traumatic Optic Neuropathy.

PURPOSE OF THE STUDY: Traumatic optic neuropathy (TON) is a rare but serious consequence of head injuries. The optimal therapy for TON remains controversial, and standardized recommendations are lacking. The most common therapies used are steroid administration and surgical decompression procedures. The aim of the present study was to compare two common conservative and surgical therapies in a rodent model with a standardized traumatic optic nerve lesion. MATERIALS AND METHODS: This study employed 59 male Wistar rats. After exposing the optic nerve, defined trauma was exerted on the optic nerve using a micromanipulator to trigger TON. Rats received either "megadose" methylprednisolone applied perioperatively or decompression via nerve sheath fenestration. The number of neurons was histologically evaluated in retinae explanted as whole mounts. Neuronal size was determined histomorphometrically. RESULTS: Neuronal loss was significantly lower following perioperative "megadose" steroid therapy (p = .017), especially in the central retinal area (p = .025). Compared to the control group without therapy, on average more than 400 neurons/mm2 were saved. In the central retinal area, more than 600 neurons/mm2 were rescued. In contrast, neuronal loss was not significantly affected by surgical decompression; however, this procedure was associated with a reduction in neuron size (p = .003). CONCLUSIONS: The present model revealed significant neuroprotective effects following administration of methylprednisolone for TON treatment. Mitigation of neuronal loss may result in functional benefits. Neuroprotective effects were not observed following surgical therapy, suggesting that this approach should be reserved for individual cases such as hematomas in the area of nerve envelopes.

Comparison of conventional and digital workflow for dental rehabilitation with a novel patient-specific framework implant system: an experimental dataset evaluation.

PURPOSE: This study aimed to evaluate the efficiency of a digital workflow by comparing the accuracy of prosthetic teeth positioning between virtual standard-size digitally constructed and conventional dental laboratory-fabricated prostheses. METHODS: Twenty-five computed tomography datasets with a dentate upper jaw were selected after applying inclusion criteria to 100 random datasets obtained from the institutional library, and partially edentulous maxillae were constructed virtually. Digital datasets of temporary prostheses were fabricated on these virtually constructed edentulous maxillae in two ways: one dataset comprised prostheses that were fabricated conventionally using prosthetic teeth and wax in the dental laboratory and then scanned using a model scanner, whereas the other dataset was designed virtually using standardized virtual dental arches. The digital datasets of both prostheses were compared for differences at six dental-based measurement points with the original patient dentition. RESULTS: Overall, the conventional design pathway was more accurate than the digital one (conventional 2.915 ± 1.388 mm, digital 3.609 ± 2.052 mm, P < 0.001). However, when all six measurement points were evaluated individually, only three points showed significant differences in the tooth positions. Compared with the original dentition, the deviations were less in the anterior teeth region than in the molar region, fulfilling the esthetic expectations of the patients. Standardized virtual dental arches were practically adequate because virtual reconstruction of every edentulous case using these virtual arches was possible without any additional modifications. CONCLUSION: It is possible to fabricate clinically acceptable temporary prostheses using a comprehensive digital workflow based on standardized digital dental arches.

Referencing for intraoperative navigation: Evaluation of human bias.

Navigation-assisted surgery is the gold standard for complex reconstructive procedures of the midface and facial skeleton, and artificial and anatomical landmarks are often used for reference. The correct identification of these landmarks before surgery is crucial for the accuracy of the navigation system. This study aimed to investigate the human errors in reference point placement. This retrospective study investigated 228 reference-point positions in 51 cases where navigation was utilized. The discrepancies between the actual reference point-position and manually planned preoperative reference points were quantified using Brainlab iPlanCMF 3.0.6. The referencing methods used in these cases included dental registration splints, osteosynthesis materials, anatomical landmarks, and combinations of these methods. The average discrepancy in the actual and manually planned reference points was 0.29 ± 0.41 mm. The use of anatomical landmarks demonstrated a significantly lower deviation (p < 0.05), although the differences between the errors in reference-point placement using dental registration splints, osteosynthesis materials, or combinations of these methods were not statistically significant. The frequency of misplacement of reference points was significantly higher than expected. These errors might have been caused by human bias during manual placement of the points or intraoperative difficulties caused by extensive metal artifacts. Thus, we postulate that the surgical personnel involved in planning navigation-assisted surgery should undergo intensive training. The development of new referencing methods that are less susceptible to these causes of error might help overcome human bias.