A new option for education during surgical procedures and related clinical anatomy in a virtual reality workspace.

The COVID-19 pandemic and mandatory social distancing has brought challenges to anatomy educators who generally need in-person classes. The purpose of this study is to share the experience of a distant online lecture on a surgical procedure and related anatomy in a three-dimensional (3D) virtual reality (VR) workspace and to compare it with reported teaching methods, that is, an in-person class and a Zoom online class. The lecture was delivered by three authors of this article in a VR workspace that enables people to meet through VR. The lectures were about combinations of dental surgical procedures and related clinical anatomy. Physically, the attendees could have been located anywhere in the world, so lecturers joined from the United States and the attendees were all from Japan. VR environment and its flexibility enabled attendees to join the lecture actively, helping them to gain understanding of the surgical procedure and anatomy more efficiently. The use of VR technology with a live communication tool demonstrated in this study has several advantages over previous education methods, although there are still technical issues or disadvantages that need to be addressed. Development of the technology and app/software is required so that more data can be processed at higher speed. Use of VR technology with a live communication tool could be an alternative teaching method. Its overall advantages are a closer look at the slides/monitor and concurrent observation of the multiple assets in various directions by multiple attendees. These advantages cannot be achieved by any other teaching method without VR assets with the workspace provided by Spatial. Even during the mandatory social distancing due to the COVID-19 pandemic, this could enable us to foster 3D understanding of surgery and related anatomy. Further study is now needed to evaluate the effectiveness of this newly proposed teaching method by comparing it with traditional in-person and online classes with a live communication tool.

Review of Risk Assessment of Major Anatomical Variations in Clinical Dentistry: Accessory Foramina of the Mandible.

Most of the studies of the mandible's anatomical variations have presented the authors' speculations, and only a limited number has provided evidence that demonstrated the actual complications injury to the variant structures caused. To our knowledge, no study has evaluated the risks associated with these variant anatomical structures' injury. We reviewed articles that described clinical cases of the injury to, and anatomical studies of, three anatomical variants of the mandible-the accessory mental, lingual, and retromolar foramina-with which dentists are relatively familiar and that are mentioned often in the context of implant and third molar surgeries, to describe risk assessment methods with which to evaluate potential complications preoperatively. Only a limited number of the clinical reports of injury to the mandible's accessory foramina were available. The potential severe complication of injury of the accessory mental foramen (AMF) is sensory disturbance of the lower lip. Risk of neurosensory disturbance of lower lip can be assessed by AMF/MF ratio and positional relations to the MF. Potential severe complication of injury of the lingual foramen is bleeding and hemorrhage in the oral cavity's floor. Risk of bleeding can be assessed by diameter and positional relation between the mental spine/mylohyoid line. A risk assessment of the retromolar foramen could not be made because of inadequate data. We hope the risk assessments suggested will encourage dentists to predict intraoperative/postoperative complications caused by damaging the mandible's accessory foramina. Clin. Anat. 32:672-677, 2019. © 2019 Wiley Periodicals, Inc.

Intraoral Observation of the Mentalis and Incisivus Labii Inferioris Muscles.

The mentalis (MT) and the incisivus labii inferioris (ILI), which are accessory muscles of the orbicularis oris (OO) muscle, form an intertwined and three-dimensionally related complex. The purpose of this study is to clarify the relationship between the MT, ILI, and OO muscles via intraoral dissection. Twenty-two sides from 11 fresh adult Caucasian cadaveric heads were used, and the MT, ILI, and OO dissected under the surgical microscope. Next, measurements of the bony attachment were carried out on another 12 sides. The fibers of the MT were separated into 2 parts: a superior and an inferior part with the former coursing anteromedially and joining the inferior part of the OO. The latter coursed anteroinferiorly to the skin of the chin. The ILI traveled anterolaterally and joined the inferior part of the OO. Inferior labial branches of the mental nerves ran on the OO. There was a significant difference (P = 0.0001) between specimens that were edentulous or had severe periodontitis with regard to the distance from the alveolar ridge to the upper side of the quadrangle when compared with specimens with mild periodontitis. However, there was no significant difference (P > 0.05) between specimens that were edentulous or had severe periodontitis specimens with mild periodontitis with regard to the distance from the inferior border of the mandible to the lower side of the quadrangle. We believe that the observations of this study could help surgeons better understand the anatomy of the chin and minimize complications following surgical and other invasive procedures in this area.

A new space of the face: The bucco-mandibular space.

Our previous studies based on intraoral dissection of fresh cadavers demonstrated the fissure and loose connective tissues behind the mucosa between the incisivus labii inferioris (ILI) and buccinator (BM) muscles. However, this raised new questions about the relationship among these muscles, the fissure and the buccal space. To our knowledge, no pathway to the oral cavity from the buccal space has been previously demonstrated, although such a pathway would better explain some routes of infection. Therefore, the aim of this study was to clarify the relationship among the mimetic muscles attached to the mandible, the fissure, and the buccal space. Twenty sides from 10 fresh frozen adult cadaveric Caucasian heads were used. The relationships among the ILI, BM, mandible, and buccal space were investigated with dissection and fluoroscopy. In all specimens, the fissure between the lateral border of the ILI and the anterior border of the BM formed the entrance of a space (here termed the bucco-mandibular space), which corresponded to the buccal mucosa in the premolar region. The superior border of this space was formed by the platysma and associated fascia, which was continuous with the masseteric fascia. This fascia clearly separated this space from the buccal space, which was located lateral to the BM and superior to this space. Clin. Anat. 30:958-962, 2017. © 2017 Wiley Periodicals, Inc.

New supplemental landmark for the greater palatine foramen as found deep to soft tissue: application for the greater palatine nerve block.

PURPOSE: Many researches have investigated the morphology of the greater palatine foramina using dry skulls and cone-beam computed tomography. In most studies, some structures in the hard tissue have been measured and statistically analyzed. However, none of the studies has analyzed this foramen in regard to its location with overlying soft tissues, which is so clinically relevant. Therefore, this study was performed to provide the knowledge about relationship between the greater palatine foramen and foveola palatina for a better understanding of dental procedures such as greater palatine nerve block. METHODS: Thirty sides, from fifteen fresh cadaveric heads, were used in this study. The specimens were derived from eight males and seven females. A 27-gauge needle was inserted into the fossa, which was palpated at the edge of a dental mirror at a 45° angle to the occlusal plane and parallel to the sagittal plane. The anteroposterior distance, which was parallel to the midline, between the penetration site and foveola palatina was measured. RESULTS: All the penetrations advanced to the greater palatine foramen. The distances ranged from 2.0 to 8.3 mm on right sides, and 1.1 to 8.2 mm on left sides, respectively. CONCLUSION: The results of this study could help dentists identify the correct location of the greater palatine foramen with a supplemental landmark.

A Novel Method for Observation of the Mandibular Foramen: Application to a Better Understanding of Dental Anatomy.

Cone-beam computed tomography gives us much useful morphological information about the mandibular bone. Many studies of the mandible include findings from this technique. However, there have been no endoscopic studies of the mandible. Sixteen sides of eight dry mandibles resected from cadavers (age range 38-83 years) were examined by endoscopy. The head of the endoscope was 2.0 mm in diameter. We examined the mandibular foramen, lingula, mylohyoid groove, and mandibular canal. The mylohyoid grooves showed variations such as double grooves and canals. The mandibular lingula was located superior or medial to the the mandibular foramen. In a single case, the medial wall inside the mandibular canal showed a porous surface. The retromolar canal was observed in three sides. None of the images in the present study have been seen in other studies. Observation of the retromolar canal from the mandibular canal in particular can help dental students as well as oral and maxillofacial surgeons to understand its morphology. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1875-1880, 2017. © 2017 Wiley Periodicals, Inc.