Detecting Mandible Fractures in CBCT Scans Using a 3-Stage Neural Network.

After nasal bone fractures, fractures of the mandible are the most frequently encountered injuries of the facial skeleton. Accurate identification of fracture locations is critical for effectively managing these injuries. To address this need, JawFracNet, an innovative artificial intelligence method, has been developed to enable automated detection of mandibular fractures in cone-beam computed tomography (CBCT) scans. JawFracNet employs a 3-stage neural network model that processes 3-dimensional patches from a CBCT scan. Stage 1 predicts a segmentation mask of the mandible in a patch, which is subsequently used in stage 2 to predict a segmentation of the fractures and in stage 3 to classify whether the patch contains any fracture. The final output of JawFracNet is the fracture segmentation of the entire scan, obtained by aggregating and unifying voxel-level and patch-level predictions. A total of 164 CBCT scans without mandibular fractures and 171 CBCT scans with mandibular fractures were included in this study. Evaluation of JawFracNet demonstrated a precision of 0.978 and a sensitivity of 0.956 in detecting mandibular fractures. The current study proposes the first benchmark for mandibular fracture detection in CBCT scans. Straightforward replication is promoted by publicly sharing the code and providing access to JawFracNet on grand-challenge.org.

German S3 guideline on the use of dental ceramic implants.

PURPOSE: Based on the excellent long-term data, dental implants made of titanium are considered the international implantological standard for replacing missing teeth. However, ceramic implants made of zirconia (ZrO2) have experienced a renaissance in the last 15 years due to constant innovations in materials and products, with material properties and soft tissue- and osseointegration behavior comparable to those of titanium. However, one limitation concerning ceramic implants is the lack of reliable long-term data, especially in the case of two-piece implant systems. As there is an increasing demand for ceramic implants from practitioners and patients, the German Society for Implantology (DGI) has decided to develop a guideline on the use of dental ceramic implants at the highest available evidence level with the involvement of experts in this field. METHODS: Statements and recommendations were prepared after conducting a systematic literature search and an independent assessment process involving the relevant clinical literature from 2008 to 2021. The adopted recommendations and statements are summarized in this guideline. RESULTS AND CONCLUSIONS: It confirms the feasible use of one-piece zirconia implants as an addendum/alternative to titanium implants. No final conclusion regarding the application of two-piece ceramic implant systems could be drawn on the basis of the existing data, thus its use can only be recommended after the patient has been informed in detail about the lack of long-term clinical data.

The impact of the COVID-19 pandemic on the dental-maxillofacial emergency service of a German university hospital in the year 2020.

OBJECTIVES: COVID-19 is considered one of the most serious pandemic in history and has posed major challenges to the world's health care. Dentistry and oral and maxillofacial surgery (CMFS) are particularly affected due to direct exposure to the respiratory tract, as the reservoir of SARS-CoV-2. In this study, the impact of the COVID-19-pandemic on a dental and CMFS emergency services in Germany in 2020 was first time investigated and correlated with governmental restriction measures in public life. MATERIALS AND METHODS: Epidemiological data of a German University Hospital were analysed from a total of 8386 patients in 2019 and 2020. Parameters included information on demographics, time, weekday and reason for presentation, as well as diagnosis and therapy performed. Data from 2020 were compared with those from 2019, taking into account the nationwide periods of public life restrictions. RESULTS: In 2020, 22% fewer patients presented via dental and CMFS emergency service. In a monthly comparison, there were negative peaks of up to - 41% in November, but also a plus of 26% in July. The largest decreases were recorded during the lockdown periods in spring (- 33%) and winter (- 39%). Further, a threefold increase in actual emergencies and inpatient admissions revealed during these time periods (p < 0.001). CONCLUSIONS: COVID-19 pandemic had a significant impact on the dental and CMFS emergency service in 2020 resulting in more severe cases. CLINICAL RELEVANCE: This study underlines the importance of maintaining an emergency service system and basic outpatient care in these specialities, which requires uniform recommendations from the medical-dental societies and politics.

Hyperspectral analysis for perioperative perfusion monitoring-a clinical feasibility study on free and pedicled flaps.

OBJECTIVES: In reconstructive surgery, flap monitoring is crucial for early identification of perfusion problems. Using hyperspectral imaging (HSI), this clinical study aimed to develop a non-invasive, objective approach for perfusion monitoring of free and pedicled flaps. MATERIAL AND METHODS: HSI of 22 free (FF) and 8 pedicled flaps (PF) in 30 patients was recorded over time. Parameters assessed were tissue oxygenation/superficial perfusion (0-1 mm) (StO2 (0-100%)), near-infrared perfusion/deep perfusion (0-4 mm) (NIR (0-100)), distribution of haemoglobin (THI (0-100)), and water (TWI (0-100)). Measurements up to 72 h were correlated to clinical assessment. RESULTS: Directly after flap inset, mean StO2 was significantly higher in FF (70.3 ± 13.6%) compared with PF 56.2 ± 14.2% (p = 0.05), whereas NIR, THI, and TWI were similar (NIR_p = 0.82, THI_p = 0.97, TWI_p = 0.27). After 24 h, StO2, NIR, THI, and TWI did not differ between FF and PF. After 48 h, StO2, NIR, and TWI did not differ between FF and PF whereas THI was significantly increased in FF compared with PF(p = 0.001). In three FF, perfusion decreased clinically and in HSI, 36(1), 40(2), 5(3), and 61(3) h after flap inset which was followed by prompt intervention. CONCLUSIONS: StO2 < 40%, NIR < 25/100, and THI < 40/100 indicated arterial occlusion, whereas venous problems revealed an increase of THI. In comparison with FF, perfusion parameters of PF were decreased after flap transfer but remained similar to FF later on. CLINICAL RELEVANCE: HSI provides objective and non-invasive perfusion monitoring after flap transplantation in accordance to the clinical situation. With HSI, signs of deterioration can be detected hours before clinical diagnosis.

Ankylosis of the temporomandibular joint-impression free CAD/CAM based joint replacement using patient-specific implants.

In recent years, alloplastic temporomandibular joint (TMJ) replacement has become a permissible procedure for the reconstruction of severely destroyed TMJs. The use of computer-aided design/computer-aided manufacturing (CAD/CAM) has extended the range of applications to complex anatomical situations. The aim of the treatment is to improve the usually restricted mouth opening and thus oral hygiene and nutrition, which leads to a regular improvement in the general quality of life. The following case report describes the bilateral replacement of ankylotically destroyed TMJs using patient-specific endoprostheses with simultaneous displacement of the maxilla. Innovative in the case described is the impression-free CAD/CAM planning, whereby the upper and lower prostheses were produced on the basis of 3D printed patient models.

[Digitalization and use of artificial intelligence in microvascular reconstructive facial surgery]. / Digitalisierung und Ansätze künstlicher Intelligenz in der mikrovaskulär-rekonstruktiven Gesichtschirurgie.

BACKGROUND: When using digitalization and artificial intelligence (AI), large amounts of data (big data) are produced, which can be processed by computers and used in the field of microvascular-reconstructive craniomaxillofacial surgery (CMFS). OBJECTIVE: The aim of this article is to summarize current applications of digitalized medicine and AI in microvascular reconstructive CMFS. MATERIAL AND METHODS: Review of frequent applications of digital medicine for microvascular CMFS reconstruction, focusing on digital planning, navigation, robotics and potential applications with AI. RESULTS: The broadest utilization of medical digitalization is in the virtual planning of microvascular transplants, individualized implants and template-guided reconstruction. Navigation is commonly used for ablative tumor surgery but less frequently in reconstructions. Robotics are mainly employed in the transoral approach for tumor surgery of the hypopharynx, whereas the use of AI is still limited even if possible applications would be automated virtual planning and monitoring systems. CONCLUSION: The use of digitalized methods and AI are adjuncts to microvascular reconstruction. Automatization approaches and simplification of technologies will provide such applications to a broader clientele in the future; however, in CMFS, robotic-assisted resections and automated flap monitoring are not yet the standard of care.

Facial cutaneous squamous cell carcinoma - microscopic safety margins and their impact on developing local recurrences.

OBJECTIVES: Surgical excision remains the treatment of choice for facial cutaneous squamous cell carcinoma (cSCC) despite there being no generally accepted diameter of clear margins. Therefore, the aim of this study was to evaluate the impact of microscopic clear margins diameter (mCMD) with respect to the development of local recurrences (LR). MATERIALS AND METHODS: The medical records of 99 patients with a total of 142 cases of facial cSCC, who underwent surgical treatment between January 2010 and December 2015, were reviewed for demographic data and clinicopathological features. RESULTS: 100 cases were diagnosed as primary cSCC and 42 cases as secondary cSCC. Of these, nine (6.3%) developed LR. Mean time to LR was 20 months, with the cheek as the predominant site 55.5% (n = 5). Wound closure was either primary (56%) or secondary (44%), depending on the site. Although no significant correlation between mCMD and LR was found (rPearson = 0.029; rPearson = 0.015), >4.1 mm was shown to be a negative cut-off-value (horizontally and vertically) without LR (100% vs 0%). CONCLUSIONS: Based on these results, however descriptive they are, the authors consider histological confirmation of clear margins to be necessary for reducing the formation of LR. Thus, consistent testing and histopathological reporting, in a multicentered effort, are needed to further clarify the role of mCMD in the development of cSCC-LR.

Prospective clinical study comparing intraligamentary anesthesia and inferior alveolar nerve block for extraction of posterior mandibular teeth.

OBJECTIVES: The aim of the study was to compare the efficacy of intraligamentary anesthesia (ILA) with conventional inferior alveolar nerve block (IANB) for extraction of mandibular posterior teeth. MATERIALS AND METHODS: In a prospective clinical trial, a total of 301 mandibular posterior teeth were extracted in 266 patients. Randomization was conducted into those who received ILA (patients n = 98; teeth n = 105) and those who received IANB (patient n = 140; teeth n = 140). Twenty-eight patients were subjected to bilateral mandibular dental extractions and received both ILA und IANB (teeth n = 56 (ILA n = 28; IANB n = 28)). The primary objective was to evaluate the differences in pain during injection, in pain during tooth extraction (numeric rating scale (NRS)), and in anesthetic quality (complete/sufficient vs. insufficient/no effect). Differences in latency time, amount of anesthetic solution, need for second injection, and duration of local numbness as well as in the incidence of dry socket were assessed. RESULTS: ILA had significant lower pain of injection (p < 0.001), shorter latency time (p < 0.001), and shorter duration of local numbness (p < 0.001) and required lesser amount of local anesthetic solution (p < 0.001) together with a similar anesthetic quality (p = 0.082) compared to IANB. Concerning pain during extraction (p = 0.211), frequency of second injection (p = 0.197), and incidence of dry socket (p = 0.178), no significant differences were detected. CONCLUSION: ILA fulfills the requirements of a minimal invasive and patient-friendly local anesthetic technique. In accordance, it represents a safe and reliable alternative to IANB for extraction of mandibular posterior teeth. CLINICAL RELEVANCE: ILA can be recommended for routine dental extractions.

Cellular fluid shear stress on implant surfaces-establishment of a novel experimental set up.

BACKGROUND: Mechanostimuli of different cells can affect a wide array of cellular and inter-cellular biological processes responsible for dental implant healing. The purpose of this in vitro study was to establish a new test model to create a reproducible flow-induced fluid shear stress (FSS) of osteoblast cells on implant surfaces. METHODS: As FSS effects on osteoblasts are detectable at 10 dyn/cm2, a custom-made flow chamber was created. Computer-aided verification of circulation processes was performed. In order to verify FSS effects, cells were analysed via light and fluorescence microscopy. RESULTS: Utilising computer-aided simulations, the underside of the upper plate was considered to have optimal conditions for cell culturing. At this site, a flow-induced orientation of osteoblast cell clusters and an altered cell morphology with cellular elongation and alteration of actin fibres in the fluid flow direction was detected. CONCLUSIONS: FSS simulation using this novel flow chamber might mimic the peri-implant situation in the phase of loaded implant healing. With this FSS flow chamber, osteoblast cells' sensitivity to FSS was verified in the form of morphological changes and cell re-clustering towards the direction of the flow. Different shear forces can be created simultaneously in a single experiment.