Deep learning for 3D cephalometric landmarking with heterogeneous multi-center CBCT dataset.

Cephalometric analysis is critically important and common procedure prior to orthodontic treatment and orthognathic surgery. Recently, deep learning approaches have been proposed for automatic 3D cephalometric analysis based on landmarking from CBCT scans. However, these approaches have relied on uniform datasets from a single center or imaging device but without considering patient ethnicity.

Reproducibility analysis of automated deep learning based localisation of mandibular canals on a temporal CBCT dataset.

Preoperative radiological identification of mandibular canals is essential for maxillofacial surgery. This study demonstrates the reproducibility of a deep learning system (DLS) by evaluating its localisation performance on 165 heterogeneous cone beam computed tomography (CBCT) scans from 72 patients in comparison to an experienced radiologist's annotations. We evaluated the performance of the DLS using the symmetric mean curve distance (SMCD), the average symmetric surface distance (ASSD), and the Dice similarity coefficient (DSC).

Ultra-low-dose CBCT: new cornerstone of paranasal sinus imaging.

Background: This study evaluates the clinical image quality (IQ) and usability of a sinonasal ultra-low-dose (ULD) cone-beam computed tomography (CBCT) scan. The results are compared to those of a high resolution (HR) CBCT scan to identify the strengths and weaknesses of a ULD CBCT protocol.

Methodology: Sixty-six anatomical sites in 33 subjects were imaged twice using two imaging modalities: HR CBCT (Scanora 3Dx scanner; Soredex, Tuusula, Finland) and ULD CBCT (Promax 3D Mid scanner; Plandent, Helsinki, Finland).

Comparison of deep learning segmentation and multigrader-annotated mandibular canals of multicenter CBCT scans.

Deep learning approach has been demonstrated to automatically segment the bilateral mandibular canals from CBCT scans, yet systematic studies of its clinical and technical validation are scarce. To validate the mandibular canal localization accuracy of a deep learning system (DLS) we trained it with 982 CBCT scans and evaluated using 150 scans of five scanners from clinical workflow patients of European and Southeast Asian Institutes, annotated by four radiologists. The interobserver variability was compared to the variability between the DLS and the radiologists.

Comparison of subjective image analysis and effective dose between low-dose cone-beam computed tomography machines.

Objectives: To compare the cone-beam computed tomography (CBCT) image quality and effective dose between low-dose scanning and standard manufacturer-recommended protocols among different CBCT units.

Methods: Three human-equivalent phantoms were scanned using the ultra-low-dose (ULD), low dose (LD), and standard dose (STD) modes of ProMax 3D Mid (Planmeca Oy, Helsinki, Finland) and Orthophos SL (Sirona, Bensheim, German) for the CBCT images. The quality of the dental anatomical images was assessed by four experienced oral and maxillofacial radiologists using a 5-point Likert scale.

Ultra-low-dose CBCT scan: rational map for ear surgery.

Purpose: This study will evaluate the clinical quality and usability of peripheral image data from the temporal bone area obtained using a sinonasal ultra-low-dose (ULD) cone-beam computed tomography (CBCT) scan and compare them to those obtained using a high-resolution (HR) CBCT.

Methods: The population consisted of 66 anatomical sites (ears of 33 subjects) imaged using two modalities: an HR CBCT (Scanora 3Dx scanner; Soredex, Tuusula, Finland) and a ULD CBCT (Promax 3D Mid scanner; Plandent, Helsinki, Finland). The image quality (IQ) for every anatomical site in each image was rated using a Likert scale from 0 to 5.

MRI of odontogenic maxillofacial infections: diagnostic accuracy and reliability.

Objectives: To determine the diagnostic accuracy of emergency magnetic resonance imaging (MRI) in odontogenic maxillofacial infections, the clinical and surgical significance of MRI findings, and whether MRI can identify the tooth responsible for the infection.

Methods: A retrospective cohort study reviewed 106 emergency neck MRI scans of patients with neck infections of odontogenic origin. The diagnostic accuracy of MRI in identifying abscesses was studied relative to surgical findings.

Evaluation of virtual handles for dental implant manipulation in virtual reality implant planning procedure.

Purpose: Many surgical complications can be prevented by careful operation planning and preoperative evaluation of the anatomical features. Virtual dental implant planning in three-dimensional stereoscopic virtual reality environment has advantages over three-dimensional projections on two-dimensional screens. In the virtual environment, the anatomical areas of the body can be assessed and interacted with in six degrees-of-freedom.

Evaluation of voice commands for mode change in virtual reality implant planning procedure.

Purpose: In dental implantology, the optimal placement of dental implants is important to meet functional and aesthetic requirements. Planning dental implants in virtual three-dimensional (3D) environment is possible using virtual reality (VR) technologies. The three-dimensional stereoscopic virtual reality environment offers advantages over three-dimensional projection on a two-dimensional display.

Association between Oral Pathology, Carotid Stenosis, and Oral Bacterial DNA in Cerebral Thrombi of Patients with Stroke.

Methods: Thrombus aspirates and control arterial blood were taken from 71 patients (70.4% male; mean age, 67.4 years) with acute ischemic stroke.

Assessment of PIV performance in validating CFD models from nasal cavity CBCT scans.

Objective: The aim of our study was to investigate how well Particle Image Velocimetry (PIV) measurements could serve Computational Fluid Dynamics (CFD) model validation for nasal airflow.

Material And Methods: For the PIV measurements, a silicone model of the nose based on cone beam computed tomography (CBCT) scans of a patient was made. Corresponding CFD calculations were conducted with laminar and two turbulent models (k-ω and k-ω SST).

Deep Learning Method for Mandibular Canal Segmentation in Dental Cone Beam Computed Tomography Volumes.

Accurate localisation of mandibular canals in lower jaws is important in dental implantology, in which the implant position and dimensions are currently determined manually from 3D CT images by medical experts to avoid damaging the mandibular nerve inside the canal. Here we present a deep learning system for automatic localisation of the mandibular canals by applying a fully convolutional neural network segmentation on clinically diverse dataset of 637 cone beam CT volumes, with mandibular canals being coarsely annotated by radiologists, and using a dataset of 15 volumes with accurate voxel-level mandibular canal annotations for model evaluation. We show that our deep learning model, trained on the coarsely annotated volumes, localises mandibular canals of the voxel-level annotated set, highly accurately with the mean curve distance and average symmetric surface distance being 0.

Three-Dimensional Printing of the Nasal Cavities for Clinical Experiments.

3D printing has produced many beneficial applications for surgery. The technique´s applicability in replicating nasal cavity anatomy for clinical use has not been studied. Our aim was to determine whether 3D printing could realistically replicate the nasal cavities and the airflow passing through them from a clinical point of view.

Effect of Maxillomandibular Advancement Surgery on Pharyngeal Airway Volume and Polysomnography Data in Obstructive Sleep Apnea Patients.

Purpose: To study volumetric changes in the upper airway in patients with obstructive sleep apnea (OSA) after maxillomandibular advancement (MMA) and compare those findings with polysomnographic (PSG) data of the same patients.

Materials And Methods: The study included 20 patients with OSA (1 woman and 19 men; mean age, 48 yr; range, 31 to 59 yr). Mean values of angles formed by the sella, nasion, and B point and the sella, nasion, and A point before surgery indicated mandibular and maxillary retrognathia, respectively.

Diagnosis of Newly Delivered Mothers for Periodontitis with a Novel Oral-Rinse aMMP-8 Point-of-Care Test in a Rural Malawian Population.

A novel qualitative point-of-care test of activated matrix metalloproteinase-8 (aMMP-8) using noninvasive oral rinse sampling procedures has been developed for the early detection of collagen breakdown indicating periodontal tissue destruction. The main object of this study was to assess the reliability of the test in a low-income setting to identify participants with history of periodontal destruction detected as alveolar bone loss (ABL) in radiographs. This cross-sectional study included 486 women who had recently delivered in rural Malawi.

Periapical infection may affect birth outcomes via systemic inflammation.

Objectives: Maternal dental periapical infections are associated with preterm birth and intrauterine growth restriction. This study investigates whether the association is mediated through bacterial spread from periapical lesions to placenta (direct pathway) or systemic inflammatory reaction (indirect pathway).

Materials And Methods: We compared birth outcomes in Malawian mothers with and without periapical infection.

Impact of prone, supine and oblique patient positioning on CBCT image quality, contrast-to-noise ratio and figure of merit value in the maxillofacial region.

Objectives: To assess the impact of supine, prone and oblique patient imaging positions on the image quality, contrast-to-noise ratio (CNR) and figure of merit (FOM) value in the maxillofacial region using a CBCT scanner. Furthermore, the CBCT supine images were compared with supine multislice CT (MSCT) images.

Methods: One fresh frozen cadaver head was scanned in prone, supine and oblique imaging positions using a mobile CBCT scanner.

Critical distance between the cartilaginous Eustachian tube and the internal carotid artery.

During the last decade, endoscopic surgery of the Eustachian tube (ET) has been advocated for ET dilatory dysfunction and for patulous ET. The internal carotid artery (ICA) and the ET are closely related, and knowledge of their surgical anatomy has become essential. This study was designed to establish the anatomical relationships between the endoscopically critical area along the full length of the cartilaginous ET and its closest association with the ICA.

Association between maternal dental periapical infections and pregnancy outcomes: results from a cross-sectional study in Malawi.

Objectives: Maternal infections are associated with intrauterine growth restriction (IUGR) and preterm birth (PTB). Dental infections are common in low-income settings, but their contribution to adverse pregnancy outcomes is unknown. We studied the epidemiology of dental periapical infections among pregnant women and their association to foetal growth restriction and the duration of pregnancy in a rural sub-Saharan African population.

Nutrient supplementation may adversely affect maternal oral health--a randomised controlled trial in rural Malawi.

Nutritional supplementation during pregnancy is increasingly recommended especially in low-resource settings, but its oral health impacts have not been studied. Our aim was to examine whether supplementation with multiple micronutrients (MMN) or small-quantity lipid-based nutrient supplements affects dental caries development or periodontal health in a rural Malawian population. The study was embedded in a controlled iLiNS-DYAD trial that enrolled 1391 pregnant women <20 gestation weeks.

Assessment of the effective dose in supine, prone, and oblique positions in the maxillofacial region using a novel combined extremity and maxillofacial cone beam computed tomography scanner.

Objective: The objectives of this study were to assess the organ and effective doses (International Commission on Radiological Protection [ICRP] 103 standard) resulting from supine, prone, and oblique phantom positions in the maxillofacial region using a novel cone beam computed tomography (CBCT) device and to compare the results with conventional dental CBCT and multislice computed tomography (MSCT) devices.

Study Design: Measurements were performed using an anthropomorphic RANDO head phantom (Radiation Analogue Dosimetry System) with 20 MOSFET (metal-oxide-semiconductor field-effect transistor) dosimeters placed in the most radiosensitive maxillofacial organs. Effective doses were measured in 3 phantom positions using a combined extremity and maxillofacial CBCT device: the Planmed Verity CBCT scanner.

A texture analysis method for MR images of airway dilator muscles: a feasibility study.

Objectives: Airway dilator muscles play an important role in the analysis of breathing-related symptoms, such as obstructive sleep apnoea. Texture analysis (TA) provides a new non-invasive method for analysing airway dilator muscles. In this study, we propose a TA methodology for airway dilator muscles and prove the robustness of this method.

Trauma induced eagle syndrome.

Eagle syndrome is characterized by secondary calcification and elongation of the styloid process. Eagle syndrome is often associated with sharp, intermittent pain along the path of the glossopharyngeal nerve located in the hypopharynx and at the base of the tongue. In some cases, the stylohyoid apparatus can compress the internal and/or the external carotid arteries and their perivascular sympathetic fibres, resulting in a persistent pain radiating throughout the carotid territory.