Among the modality of diagnosis, CT/MRI has proved to have excellent ability in demonstrating normal anatomy and pathologic processes in the head and neck region. Whereas CT best depicts bone structures, MRI is superior to CT in evaluating soft tissues. The contents of bone lesions may also be better visualized on MRI. Here, I would like to consider if we can additional information for differential diagnosis in the lesions of the maxillofacial region using MRI or not. I will show the below objectives. Odontogenic cysts in the jaw bones
1. Radicular cysts
2. Dentigerous cysts
3. Odontogenic keratocysts Other cysts in the jaw bones
4. Nasopalatine duct cysts Pseudocysts
5. Simple bone cysts
6. Aneurismal bone cysts

Odontogenic benign tumors in the jaw bones
1. Ameloblastoma
2. Adenomatoid odontogenic tumor
3. Odontogenic myxoma / myxofibroma
4. Odontogenic fibroma

Vascular anomalies Malignant tumors in the oral and maxillofacial region
1. Squamous cell carcinoma
2. Malignant lymphoma
3. Solid type primary intraosseous squamous cell carcinoma of the mandible
4. Ameloblastic carcinoma primary type
5. Neuroendocrine Small Cell Carcinoma

The assessment of MRI may prove to be a valuable non-invasive method for assessing information in the oral and maxillofacial region.

The application of artificial intelligence (AI) based on deep learning in dental diagnostic imaging is increasing. Several popular deep learning tasks have been applied to dental diagnostic images.
Classification tasks are used to classify images with and without positive abnormal findings or to evaluate the progress of a lesion based on imaging findings. As the altered morphology of mandibular cortex on panoramic radiographs is significantly correlated with osteoporosis, AI is used for classification of the mandibular cortex morphology.
Region (object) detection tasks have been used for tooth identification in panoramic radiographs. This technique is useful for automatically creating a patient's dental chart. Some of these techniques have been developed and already deployed for practical use.
The segmentation task in deep learning is a technique that divides an image into objective segments. In semantic segmentation, the objects to be selected are distinguished from the background and other objects using different colours. In instance segmentation, it is possible to identify and separate individual instances of the same class of objects. This procedure may be suitable for teeth identification in panoramic radiographs with a clear view. Deep learning methods can also be used for detecting and evaluating anatomical structures of interest from images.
Generative AI is a category of AI techniques that involves creating or generating new content such as text and images. A valuable application of generative AI in dentistry is the creation of a patient's dentition and facial features, which are targeted for improvement by prosthetic or orthodontic treatment. Furthermore, generative AI based on natural language processing can automatically create written reports from the findings of diagnostic imaging.

The mandibular (inferior alveolar) canal is an important anatomical structure, which contains the inferior alveolar nerve, artery, and vein. The inferior alveolar nerve is a branch of the trigeminal nerve that controls sensation in the lower teeth and surrounding tissues, and the inferior alveolar artery is a branch of the maxillary artery. The mandibular canal extends between the mandibular and mental foramen through the lower part of the mandibular body; however, it may occasionally run in close proximity to the molar root apex. Several studies have investigated the association between an impacted third molar and the mandibular canal and highlighted several signs that are useful to prevent unexpected bleeding or nerve paralysis. Computed tomography (CT) or cone-beam CT (cross-sectional images) can clearly delineate the course of the mandibular canal and show its corticated borders. However, identification of the mandibular canal may occasionally be challenging in a few patients in whom its appearance is similar to that of cancellous bone patterns. In such cases, it is necessary to identify the mandibular canal on a sagittal panoramic view, followed by a secondary search in a para-axial view using a guide function or reference line. We observed that magnetic resonance imaging (MRI) accurately shows the structures within the mandibular canal, including the neurovascular bundle using three-dimensional (3D)-volumetric interpolated breath-hold examination (VIBE) sequences, and CT/MRI fusion images are useful to outline the course of the mandibular canal. Additionally, the 3D-VIBE sequence was useful to accurately identify a bifid mandibular canal and many nutrient canals branching from the mandibular canal. In this lecture, I will present various imaging features of the mandibular canal.

Nowadays, the placement of dental implants is a common procedure done in most dental offices. Ideal implant placement not only achieves maximum esthetic and functional outcomes but also diminishes possible surgical complications. Guided implant surgery is a cutting-edge and precise technique for implant placement. It refers to the process of digital planning, surgical guide fabrication, and implant placement using the custom-made guide.
In-office 3D printing technology has become increasingly popular in digital dentistry. Stereolithography is a powerful 3D printing technology which utilizes a liquid photopolymer resin cured by a UV laser to create highly accurate dental devices, such as an implant surgical guide. The digital workflow for in-office printing of a surgical guide starts from a CBCT and intraoral scanning. Then, the intraoral scan is imported into a software program and merged with the CBCT image data to simulate the implant position, direction, and depth, for which the surgical guide is to be designed. However, substantial errors can occur at each of these individual steps and can accumulate, significantly impacting the final accuracy of the implant placement with potentially disastrous deviations.
This presentation aims to summarize information on the accuracy and efficacy of static guided implant surgery with special emphasis on the strengths and limitations of a stereolithographic surgical guide produced using in-office 3D printing technology.
Furthermore, clinicians should recognize the limitations/weaknesses of an in-office fabricated implant guide so surgical complications can be minimized.

Pain in the orofacial regions is often seen in the daily dental practice. Among them, except dental pain, musculoskeletal pain is mostly seen. In orofacial region, the musculoskeletal pain is mainly rising from temporomandibular joint and cervical spine. For screening purpose, panoramic and lateral cephalometric images might provide valuable information, if evaluated properly. In this presentation, I will illustrate how to read them based on projection geometry and pathophysiological bases of the associated pain.

Orofacial pain, temporomandibular, cervical spine, panoramic, lateral cephalometric

Artificial intelligence (AI) has been one of the most popular studies and AI is making significant advancements in various fields. Recently there have also been many studies in oral and maxillofacial radiology field. In the field of dentistry, AI has primarily been researched in areas such as automatic pathologies diagnosis, segmentation of anatomical structures, forensic dentistry, cephalometric analysis, image quality improvement, and bone quality evaluation in the field of oral and maxillofacial radiology. Many studies related to AI have been conducted up to now, but it might be in the early stages, and further advancements are expected in AI research in the future. This presentation would introduce the current state of AI research conducted in dental field so far and considerations related with AI research in dentistry.

Artificial Intelligence; Radiology; Dentistry

Recently, many clinical lectures in the dental imaging field have done a lot of implant-related imaging lectures but there are not many general image interpretation lectures. Accordingly, I would like to talk about image interpretation of interesting textbook cases that are easily encountered in dental clinics.
If unfamiliar radiological findings are observed during patient treatment, it must first be confirmed whether the findings are normal or pathological. Once a lesion is identified, an appropriate treatment plan must be developed. Among these, the most basic and important step is the distinction between normal and pathological findings.
There are many more diverse images reading errors that are easily encountered in clinical practice, but through the cases introduced here, I hope to take the time to share with you how we can avoid experiencing the same reading errors.

dental image, interpretation, normal, pathologic

X-rays were discovered by Dr. Roentgen in 1895. Nihon University School of Dent, Department of Oral and Maxillofacial Radiology was established by Professor Noboru Teruuchi in 1924. This year marks the 100th anniversary.
During this time, we have developed Ortho Pan tomography, digital systems, and Limited volume and High resolution CBCT. It has been 25 years since clinical application began in December 1997 at the Department of Dental Radiology, Nihon University School of Dentistry, Dental Hospital.
Let's look back at this history.  Furthermore, we will introduce the latest CBCT which is X-ray elevation angle variable method with Metal Artifact Redaction.

Ortho Pan tomography, Digital systems, CBCT, Elevation angle, MAR

Oral and maxillofacial radiology (OMR) is a fast-growing dental specialty. Over the past twenty years, OMR has successfully evolved from analog to digital imaging, from 2D intra-oral and extra-oral images to 3D cone-beam computed tomography (CBCT). Recent years, Artificial intelligence (AI) and deep learning has proven to improve the quality of care in the all dental specialties by using image detection, classification, and segmentation. The arduous work of researchers for several decades has resulted in the evolution of AI, aka machine intelligence in dental charting, osteoporotic screening, caries, bone loss, apical and other lesion detections, as well as implant identifications. The latest development of generative AI will further broaden AI applications in OMR and dentistry, expedite image analysis/report and improve treatment outcome. Based on the current status AI will potentially benefit patients, oral and maxillofacial radiologists, and other dental specialists.

The other major prospect of OMR is the development of dental-dedicated MRI (ddMRI). As we all know, traditional 2D and 3D images have been focused on hard tissues of tooth and its surrounding bony structures. Latest development of ddMRI would potentially image both soft and hard tissues in oral cavity. The soft tissues, such as pulpal, neuro-vascular, mucosal, and muscular structures, are not seen on our traditional dental radiographs. This lecture will present the latest development, research, and potential clinical applications of dental AI and ddMRI in oral and maxillofacial imaging and dentistry.

Artificial intelligence (AI); Deep Learning; Generative AI; cone-beam computed tomography (CBCT); dental-dedicated Magnetic resonance imaging (ddMRI)

This presentation will highlight the use of Cone Beam Computed Tomography (CBCT) information in decision making for diagnosis, treatment options and recommendations, and assessments of post-treatment outcomes.  Cases will be used to demonstrate how CBCT has strongly influenced clinical endodontic decision making.

Additionally, CBCT can aid in the differentiation and management of endodontic failure and failure of endodontically treated teeth.  This presentation will describe the difference between these two types of treatment failure.  

Participants will learn how to provide an appropriate endodontic clinical examination, assess radiographic images of endodontically treated teeth, including CBCT images.  Discussion will include how this information will inform your diagnosis and treatment planning decisions, in order to provide patients with treatment options.

CBCT endodontics diagnosis treatment assessment

Over the past two decades, the links between oral and general health have been increasingly recognized. Mounting evidence indicates oral bacteria increase the risk of pneumonia in the elderly or contribute to postoperative complications. At Tohoku University Hospital, the Division of Perioperative Oral Management is responsible for the oral management of all inpatients in the medical division. As the director of both the division of Oral and Maxillo-facial Radiology and the division of Perioperative Oral Management, I examine the oral condition and radiographic images of patients who stay in the hospital to receive medical treatments such as surgery, medication therapy, and radiation therapy. I would like to introduce and explain my working role at Tohoku University Hospital, and demonstrate the importance of oral management based on radiographic readings for such patients.
It is well known that some systemic diseases are caused by oral diseases because of the presence of many chronic infection foci in the jaw bones, such as apical periodontitis and periodontal diseases. On the other hand, partial symptoms of the systemic disease often appear in the mouth. As such, oral and maxillofacial radiologists need to understand the interactive relationship between oral diseases and systemic diseases, because the jaw bones are susceptible to genetic and hormonal influences. Therefore, I would like to present some cases that indicate an interactive relationship between oral conditions and systemic diseases; I will then introduce my recent research developed from such experiences.
I am looking forward to discussing about the oral and maxillofacial radiographic examinations for patients with systemic diseases with everyone.

oral conditions, systemic diseases, perioperative oral management

Temporomandibular Disorder (TMD) is a multifaceted condition that involves muscles, articular disc and/or bony components of the TMJ. Previous studies have suggested a potential association between degenerative changes in the condyle and more advanced disc displacement or limited disc motion. However, the chronological relationship between disc displacement/derangement and degenerative bone changes remains unclear.

This presentation begins with an overview of the selection and findings of imaging modalities in TMD patients, including panoramic radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Clinical and image data analysis of TMD patients who underwent long term follow up will be presented. CT and MRI data from TMD patients over the course of 7-9 years were reviewed. Key points include the recognition of osseous and soft tissue structural changes over time, the correlation between imaging findings and clinical outcomes, and an investigation into whether the presence of unilateral disc displacement or unilateral degenerative changes increased the risk of contralateral disc displacement or the development of degenerative changes. The relationship between TMJ disc disorders and osteoarthritic changes will be discussed. The presentation concludes with the challenges and limitations that are inherent in the interpretation of long-term progression data derived from CT and MRI.

By the end of this presentation, attendees will gain a deeper understanding of how imaging can serve as a powerful tool in understanding the dynamic of Temporomandibular Disorder. This knowledge will facilitate better-informed, monitor, treatment strategies and improve the long-term management of TMD patients.

TMD, disc displacement, osteoarthritis, MRI, CT

Several studies that have been performed will be presented/ The studies performed to evaluate the image quality of panorama and CBCT.   
We made clinical and laboratory phantoms to study the image quality of panoramic images. The correlation between the spatial resolution of panoramic radiography and ball distortion rate was identified, and the minimum standard for ball distortion rate using a panoramic ball phantom was established. Another panoramic resolution phantom was fabricated and used to evaluated the panoramic horizontal and vertical resolution, reflecting panoramic unique characteristics. The shape of the Image layer, contrast, and spatial resolution were obtained using the phantom, and the diagnostic ability of various lesions was investigated through clinical phantoms’ imaging obtained in each exposure condition. Using CBCT phantoms, we measured the values of various factors such as modulation transfer function and contrast-to-noise ratio under various conditions, and examined the relationship between these values and clinical image quality. Finally, we will discuss the need for oral and maxillofacial image quality assessment programs and supports by institutions, or nations.

Oral and Maxillofacial, panoramic, CBCT, imaging, quality

To date, the role of genes and the environment in the etiology of malocclusion has been a topic of debate. The interaction between genetic and environmental factors starts at birth and continues till the end of life. A better understanding of the relative effects of genes and environment on dentofacial and occlusal parameters should enhance our knowledge of the etiology of orthodontic disorders and the possibilities and limitations of orthodontic treatment.

Each malocclusion has its characteristic slot in the genetic and environmental spectrum. Understanding the relationship between facial form, growth, and malocclusions is an important issue in orthodontic treatment. The great variations in growth mix and head form, population differences, and sex dimorphic variations result in a bewildering spectrum of facial types.

Cephalometric analysis is used to evaluate facial growth, to study the anatomical relationships within the face, and as a routinely used tool for treatment planning in orthodontics and craniomaxillofacial deformity surgery. A standard cephalometric assessment is based on 2D radiographic images taken in either the sagittal (lateral cephalogram) or coronal planes (posteroanterior cephalogram), where multiple landmarks, lines, and angles are identified to quantify vertical and horizontal relationships in the face.

Currently, the most angular and linear measurements are as follows: SNA, SNB, ANB, FMA, MP-FH, UI-NA, L1-MP, S-N, Co-Pt. A, Co-Gn, N- ANS…etc. SN-GoGn and FMA were found to be the most reliable indicators, whereas LAFH and TAFH are the least reliable indicators in assessing facial vertical growth patterns. Current evidence on the reliability of growth indicators in the identification of the pubertal growth spurt and efficiency of functional treatment for skeletal Class II malocclusion, the timing of which relies on such indicators, is highly controversial. In the face of so much information and uncertain factors and conclusions, it is very important to understand craniofacial features.

Growing patient, cephalometry, gene, environment

Diagnostic imaging of the maxillomandibular region is an important subsection of the head and neck radiology. Lesions developing within the maxillomandibular region can arise from the dental elements, bone, nerves, or blood vessels.
In the diagnostic imaging of the maxillomandibular region, it has been common clinical practice initially to use plain radiography including an intra- or extraoral technique and panoramic radiography. In recent years, computed tomography (CT) and magnetic resonance imaging (MRI) have been used widely to image these lesions, and they have proved effective for differential diagnosis and determination of the extent of lesions.

CT has many advantage such as excellently the degree of bone resorption, osteosclerosis, cortical bone swelling, desutruction, detect of the calcifications. In contrast, MRI is so different imaging modalities comparing with other radiological modalities. In advantage, no ionizing radiation. MRI depend on the proton density of hydrogen in tissues such as water or lipid contents and effective in differentiation between cysts and tumors, detection of abnormal bone arrow, evaluation of infiltration of malignant tumors in the maxillomandibular region and surrounding soft tissue.

My presentation is 1) to discuss the use of CT and MR imaging technique of the maxilla and mandible, 2) to demonstrate normal anatomy of the maxilla and mandible, interpretation of images, characteristic findings of CT and MR imaging, 3) to discuss the advanced imaging including diffusion MR imaging and AI (artificial intelligence) for the maxillomandibular region.

Diagnostic imaging, CT, MRI, Diffusion MR imaging, Differential diagnosis

Head and neck cancer, an immensely destructive ailment, accounts for over 890 thousand fresh cases each year and is responsible for more than 450 thousand fatalities worldwide annually. Radiation therapy (RT), whether used alone or in conjunction with other treatment approaches, possesses significant potency in managing tumors, primarily constrained by the adverse effects on surrounding healthy tissues. RT is one of the main treatments in head and neck patients that offers clinical benefits. It demonstrates biological impacts within a short timeframe ranging from hours to weeks after exposure, inducing substantial genetic harm that breaks double strands in both nuclear and mitochondrial DNA, as well as impeding cellular division and replication.
It has been challenging that radiotherapy may cause unwanted radiation-induced complications. A mounting body of evidence strongly supports the supplementation of image guided radiotherapy (IGRT). Until recently, image guidance was only performed prior to RT without simultaneous tumor tracking. Now magnetic resonance imaging-guided radiotherapy (MRgRT) enables Radiation Oncologists to actually see the targets in relation to surrounding normal tissues when the patient is on the treatment table. Immediately after inspecting anatomical changes, they are able to execute a whole new set of treatment plan according to geographical variability at that specific RT fraction. MRgRT offers not only novel planning types, such as online adaptation, but also better image guidance due to superior soft tissue contrast.
MRgRT reduces the unnecessary radiation dose to normal tissue by smaller treatment margins and facili tates visualization of the anatomical sites especially in oral cavity.

Radiotherapy; IGRT;magnetic resonance imaging-guided radiotherapy;head and neck cancer;oral cancer

Since the oral cavity has many functions, when cancer occurs in the oral cavity, it is desirable to treat it as conservatively as possible. From this perspective, expectations are high for radiotherapy.
In this lecture, I will first give an overview of radiation therapy used for oral cancer. In external radiation therapy, a large linear accelerator generating X-rays and electrons is used with IMRT and IGRT techniques. Stereotactic radiation therapy includes cyber-knife (using X-rays) and gamma-knife (using gamma rays). Heavy particle therapy (using protons or carbon ions) may be categorized as external radiation therapy.
Small-source radioisotope therapy is increasingly being used as a radical treatment for oral cancer. It can be divided into interstitial brachytherapy, mold brachytherapy, and intracavitary brachytherapy. Interstitial brachytherapy is often used for tongue cancer, and mold brachytherapy is used for superficial gingival cancer.
BNCT (boron neutron capture therapy) can be a highly effective radiotherapy with few complications when certain conditions are met. In the BNCT, alpha rays emitted by nuclear reaction between boron and neutron damage DNAs in cancer cells.
Finally, I would like to discuss the current status of internal radiotherapy using alpha rays.

Radiation therapy, Oral cancer, Interstitial brachytherapy

In contemporary endodontic practice, CBCT is pivotal for diagnosis and treatment planning. Alongside traditional technologies, such as nickel-titanium instruments, ultrasonic devices, and microscopes, CBCT enhances precision in root canal procedures and apical surgeries. Despite the reliance on clinicians' senses, additional techniques like static navigation, dynamic navigation, and 3D printing optimize the use of 3D CBCT images, enabling precise localization of calcified root canals and accurate determination of root apex positions.
This presentation explores the comprehensive integration of 3D Imaging Technology with existing microscopes and ultrasonic devices in endodontics. Topics include static navigation (guided endodontics) for localizing calcified root canals, positioning during apical surgery, and coordination with a piezotome. The discussion also encompasses dynamic navigation for challenging root canal treatments and localization in apical surgery.
Furthermore, the presentation addresses distinctions between these technologies and explores the application of artificial intelligence to convert CBCT images into 3D root canal models. The aim is to showcase how these advancements can significantly impact the field of Clinical Endodontics in modern practices.

Guided endodontics, Dynamic navigation, Artificial intelligence, CBCT, Digital Information

This lecture will cover various imaging modalities that is all in a day’s work of a dental maxillofacial radiologist.
- Salivary gland diseases and intervention with various clinical situation.
- Usage of US in various scenarios in dentistry and head and neck.
- CBCT
- Interactive session
- Case based reviews
- Interesting cases
- What happens if you are out of your depth?
- Top tips from a radiologist with 20 years’ experience

Ultrasound, CBCT, Interesting cases, Salivary glands, Head and Neck