Osteotomy training for dental students using three-dimensional simulation software and maxillofacial three-dimensional-printed models.

PURPOSE/OBJECTIVES: Simulated educational models of teeth, bones, and gums have been used for a long time in procedural skills training in dentistry.  The advent of three-dimensional (3D) printing technologies and additive manufacturing has facilitated the production of more advanced 3D printed models that can be utilized for surgical and dental training together with other technologies (e.g., 3D scanners and image analysis software). METHODS: We conducted training on osteotomy in the maxilla and mandible using maxillofacial simulation software (MSS) and a 3D-printed model for 5th-year undergraduate dental students (13 students in 2017 and 11 students in 2018 with more than half of their results). We compared the group (13 students) who performed osteotomy after participating in the simulation lecture with those (11 students) who performed osteotomy after performing self-simulation (they were instructed to bring their personal computers and install the MSS) using tests and questionnaires (pre- and post-curriculum). RESULTS: The average test score was significantly higher in the group who performed osteotomy using the 3D-printed model after performing self-simulation; participants in this group had acquired a better understanding of the surgical procedure. Comparison using questionnaires showed a significant difference in the students' understanding of instruments and surgical techniques between both groups. CONCLUSION: The MSS and 3D printed models are widely used clinically. Incorporating these in the curriculum will help accelerate student development. In addition, prompt education on the purpose and usefulness of these tools will not only facilitate simulation software and 3D-printed model-based treatment plan in the clinic but also promote further research.

A rare case of static bone cavity in the anterior mandibular region of a 10-year-old boy.

INTRODUCTION: Static bone cavity (SBC) is a bone defect that develops as a result of localized pressure from tissues surrounding the mandible. It is most commonly observed in the mandibular angle of adult males caused by the submandibular gland. The condition is asymptomatic and requires no treatment. The frequency of onset is rare, especially in the anterior mandible, and SBC is extremely difficult to diagnose in children. PRESENTATION OF CASE: This report is on a case of SBC in the anterior mandible of a 10-year-old boy. The condition could not be diagnosed after panoramic radiograph and Magnetic Resonance Imaging (MRI) analyses. Computed-topography (CT) imagery revealed an oval-shaped depression 6 × 5 × 3 mm in size at the lingual apex of the mandibular left lateral tooth. Diagnosing the patient was difficult and a tumor was suspected. For treatment, the tumor-like lesion was resected and the fistula in the periosteum was sutured and closed. One year later, the defect on the lingual mandibular bone had ossified and recovered. CONCLUSION: The incidence of SBC in children is rare and the condition is difficult to diagnose because of the small size of the lesions, however in this study, CT imagery proved to be useful. SBC was detected in the subject in early childhood, and his postoperative course suggested that the lesion developed as a result of glandular tissues herniating through the periosteum and causing compression on the mandible, which resulted in bone resorption. In other words, herniation of normal salivary glandular tissues were a cause of SBC.

A Case of Mandibular Prognathism with Generalized Aggressive Periodontitis and Crowding.

Aggressive periodontitis during adolescence has a poor prognosis due to rapid alveolar bone resorption. Few studies have investigated long-term follow-up after surgical orthodontic treatment performed in conjunction with that for invasive periodontitis. Here, we report a case of mandibular prognathism accompanied by generalized aggressive periodontitis and crowding. A 31-year-old woman was referred to our department for treatment of masticatory dysfunction due to reverse overjet. The patient exhibited a class III molar relationship, protrusion of the ANB of －6.0°, and severe maxillary crowding. Initial periodontal examination revealed deep periodontal pockets and extensive inflammation. Mandibular prognathism accompanied by generalized aggressive periodontitis and crowding was diagnosed. Therefore, it was necessary to adopt an interdisciplinary approach involving surgical, orthodontic, and periodontal treatment. Prior to commencement of orthodontic treatment, plaque control, scaling, and root planing of all teeth were performed by a periodontist to suppress inflammation and reduce probing depth. During pre-surgical orthodontic treatment, the maxillary first premolars were extracted to reduce crowding of the maxillary incisors. To correct the mandibular prognathism, the mandible was repositioned by sagittal split ramus osteotomy. Proper occlusion of the incisors and maximum intercuspation were achieved by post-surgical orthodontic treatment. After completion of active orthodontic treatment, acceleration of inflammation was observed together with aggravated resorption of the alveolar bone surrounding the molars. However, reduction of probing depth and inflammation were observed after scaling and root planing. The surgical-orthodontic treatment time was 1 year and 11 months, which was followed by a 2-year retention period. There was no tooth loss due to periodontitis, and an overall satisfactory outcome was achieved.

Assessing the Potential Earthquake Precursory Information in ULF Magnetic Data Recorded in Kanto, Japan during 2000-2010: Distance and Magnitude Dependences.

In order to clarify ultra-low-frequency (ULF) seismomagnetic phenomena, a sensitive geomagnetic network was installed in Kanto, Japan since 2000. In previous studies, we have verified the correlation between ULF magnetic anomalies and local sizeable earthquakes. In this study, we use Molchan's error diagram to evaluate the potential earthquake precursory information in the magnetic data recorded in Kanto, Japan during 2000-2010. We introduce the probability gain (PG') and the probability difference (D') to quantify the forecasting performance and to explore the optimal prediction parameters for a given ULF magnetic station. The results show that the earthquake predictions based on magnetic anomalies are significantly better than random guesses, indicating the magnetic data contain potential useful precursory information. Further investigations suggest that the prediction performance depends on the choices of the distance (R) and size of the target earthquake events (Es). Optimal R and Es are about (100 km, 108.75) and (180 km, 108.75) for Seikoshi (SKS) station in Izu and Kiyosumi (KYS) station in Boso, respectively.

A rare case of dermoid cyst arising in the upper lip.

INTRODUCTION: Generally, dermoid cysts commonly arise from the anus and ovaries. Oral and maxillofacial lesions are most commonly observed in the midline of the floor of the mouth, and lesions arising from the upper lip are relatively rare. PRESENTATION OF CASE: A 50-year-old man was referred to our hospital due to swelling of the left upper lip. Clinical examination revealed an elevated alar base, Gerber protrusion and nasal deformity. Ultrasonography revealed a clearly defined 30-mm lesion with more hypoechoic bands. Meanwhile, magnetic resonance imaging revealed a 30-mm mass below the orbicularis oris of the left upper lip. The lesion had a homogeneous, low-signal intensity on T1-weighted imaging. Thus, based on these findings, a dermoid cyst was suspected. The lesion was then removed en bloc without the overlying skin while the patient was under general anaesthesia. Histopathological examination revealed a cystic cavity lined by an orthokeratinised stratified squamous epithelium. However, skin appendages were not found. Based on the clinical and histopathological features of the lesion, a diagnosis of epidermoid cyst was made. Swelling of the left upper lip, nasal deformity and Gerber protrusion significantly improved after surgery. CONCLUSION: Although dermoid cysts arising from the upper lip are rare, the diagnostic accuracy for dermoid cyst can be improved with the combined use of ultrasonography and other imaging modalities even though these lesions are difficult to distinguish from differential diagnosis.

Surgical Management of Median Cleft Lip Extending as Far as Alveolus Using Bone Grafting.

Median clefts, which run through the midline of the upper lip, and alveolus are considered a type of craniofacial cleft. A Tessier number 0 median cleft lip is the rarest, and there are few reports concerning its surgical management. Here, we describe the case of a 6-year-old boy who presented at our hospital with a median cleft and alveolus of the upper lip with a shortened bifid frenulum. Inverted-V and Z-plasty incisions were performed for the median cleft and iliac bone grafting for the midline alveolus. At 1 year 5 months later, the postoperative course was uneventful, and proper approximation of the orbicularis oris muscle and vermilion were achieved, with a symmetrical Cupid's bow and labial tubercle and philtrum.

Two cases of prostheses for flap protection after buccal mucosal incision.

Here we describe two patients in whom prostheses were applied for flap protection after buccal mucosal incision. In the first case, the patient was a 65-year-old man with a diagnosis of buccal mucosa squamous cell carcinoma (T2N0M0). Left buccal mucosa squamous cell tumor resection and dermoplasty were performed, followed by alveolar ridge augmentation and buccal mucosal graft in the scar area. The carcinoma recurred, however, and left buccal mucosa carcinoma resection was performed, followed by reconstruction surgery using a free forearm flap. After a 12-week healing period, a molar support was constructed on the unaffected side and a protective prosthesis placed on the affected side. Training in ingestion and swallowing were given postoperatively. The patient in the second case was a 62-year-old woman with a diagnosis of buccal mucosa squamous cell carcinoma (T2N1M0). Right buccal mucosa carcinoma resection and supraomohyoid neck dissection were performed, followed by reconstruction surgery using a free forearm flap. A molar support was constructed on the unaffected side and a protective prosthesis placed on the affected side at 5 months postoperatively. Training was given in ingestion and swallowing postoperatively. The prostheses prevented bite wounds to the flaps in the affected areas due to jaw movement during swallowing or speaking. The postoperative courses were uneventful, and the average masticatory score was 92.5 (85, 100), not affecting daily life. The prostheses were placed after reconstruction surgery using free flaps after buccal mucosa squamous cell carcinoma resection. Dysphasia recovered to the preoperative level by dysphasia and pronunciation training in both cases. The postoperative prognosis was favorable, with the prosthesis preventing damage to the flap.

Simultaneous bilateral spontaneous pneumothorax with congenital pleuro-pleural communication.

A single pleural space can lead to serious simultaneous bilateral pneumothorax in cases of congenital or acquired pleuro-pleural communication. Here we report a 35-year-old man with bilateral pneumothorax. Chest computed tomography scans revealed a small air space between the esophagus and aorta, suggesting pleuro-pleural communication. Bilateral thoracoscopic bullectomy was performed. Repeated inspection revealed a 2-cm-long pleural window between the aorta and esophagus, which was closed with a collagen patch. Although congenital pleuro-pleural communication has been regarded as rare, as many as nine patients have been reported (if suspected cases are included). The lower middle mediastinum should be carefully inspected.

Postoperative evaluation of grafted bone in alveolar cleft using three-dimensional computed tomography data.

Objective : Postoperative evaluation of bone formation in the alveolar cleft by computed tomography imaging has been reported. We quantitatively evaluated bone grafts in the alveolar cleft preoperatively and postoperatively using three-dimensional data and superimposition of images. Subjects : A total of 12 patients with complete unilateral cleft lip and palate (six left-sided and six right-sided) were studied. Methods : Helical computed tomography scans were taken immediately before surgery and at 6 months after surgery and the DICOM files obtained were processed using Mimics and 3-matic software for three-dimensional data analysis. The preoperative and postoperative computed tomography data were superimposed, and the position and length of the unerupted canines and width of the alveolar cleft measured. Results : Strong and significant correlations were observed between bone formation in the alveolar cleft bone graft region and preoperative canine position (r  =  -.766, p < .01) and canine length (r  =  .681, p < .05). Stepwise multiple regression analysis demonstrated that only the preoperative canine position was independently and significantly correlated with bone formation in the alveolar cleft. Conclusion : These results indicate that the optimal timing for surgery is when the canine cusp is close to the alveolar plane.

The addition of calcium ion chelator, EGTA to thawing solution improves fertilizing ability in frozen-thawed boar sperm.

In our previous study, seminal plasma effectively suppressed the induction of sperm to capacitation-like status and acrosome loss during the thawing process. However, because boar seminal plasma is contaminated with various kinds of bacteria and/or viruses, it is necessary to develop a thawing solution without animal-derived materials. In this study, we focused on the increase of intracellular Ca(2+) ([Ca(2+)](i)) in sperm after thawing and the negative effects of sperm qualities. After thawing, the fluorescent intensity of [Ca(2+)](i) indicator, Fluo-3/AM, and the level of phosphorylated tyrosine residue of protein were increased in the sperm. Next, we investigated whether the addition of Ca(2+) chelators (ethylenediaminetetraacetic acid (EDTA) and ethyleneglycoltetraacetic acid (EGTA)) improved post-thawed sperm motility. When the frozen-thawed sperm were treated with 6 mmol/L EDTA + 6 mmol/L EGTA, sperm motility was significantly increased as compared with control (6 mmol/L EDTA alone) at all incubation periods (P < 0.05). The combinational treatment significantly suppressed the elevation of [Ca(2+)](i) and the tyrosine phosphorylation, which improved the acrosomal status and fertilizing ability in vitro. Furthermore, when the thawing method was applied for artificial insemination, the fertilization rate was significantly higher than control (P < 0.05, 33% vs. 82%). Thus, we conclude that the addition of EDTA + EGTA to thawing solution is a beneficial tool for artificial insemination using frozen-thawed boar sperm.

Degradation of the synthetic dye amaranth by the fungus Bjerkandera adusta Dec 1: inference of the degradation pathway from an analysis of decolorized products.

We examined the degradation of amaranth, a representative azo dye, by Bjerkandera adusta Dec 1. The degradation products were analyzed by high performance liquid chromatography (HPLC), visible absorbance, and electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS). At the primary culture stage (3 days), the probable reaction intermediates were 1-aminonaphthalene-2,3,6-triol, 4-(hydroxyamino) naphthalene-1-ol, and 2-hydroxy-3-[2-(4-sulfophenyl) hydrazinyl] benzenesulfonic acid. After 10 days, the reaction products detected were 4-nitrophenol, phenol, 2-hydroxy-3-nitrobenzenesulfonic acid, 4-nitrobenzene sulfonic acid, and 3,4'-disulfonyl azo benzene, suggesting that no aromatic amines were created. Manganese-dependent peroxidase activity increased sharply after 3 days culture. Based on these results, we herein propose, for the first time, a degradation pathway for amaranth. Our results suggest that Dec 1 degrades amaranth via the combined activities of peroxidase and hydrolase and reductase action.

Polymyxin B neutralizes bacteria-released endotoxin and improves the quality of boar sperm during liquid storage and cryopreservation.

Gram negative bacteria are the predominant type detected in boar semen. Since these bacteria release lipopolysaccharide (LPS), and because polymyxin B (PMB) neutralizes LPS activity, the objective was to improve techniques for long-term storage of boar sperm by testing the beneficial effects of PMB. In the present study, LPS bound directly to the head region of sperm, decreased sperm motility, and induced sperm apoptosis. The addition of 100 µg/mL PMB suppressed LPS binding activity and blocked the negative effects of LPS on sperm quality. Additionally, when PMB treatment was combined with penicillin G (PenG), sperm motility was increased after 10 d of liquid storage or in frozen-thawed sperm (P<0.05). When the PMB- and PenG-treated sperm was used for artificial insemination, the conception rate was increased relative to that of artificial insemination with sperm treated by PenG alone in both liquid (62 vs. 81%) and cryopreserved forms (50 vs. 80%, P < 0.05). We concluded that PMB suppressed LPS-induced low sperm motility and apoptosis via the reduction of LPS binding to Toll-like receptors (TLRs). Thus, in order to enhance sperm quality for artificial insemination, a combined treatment with PMB and PenG immediately after ejaculation seemed appropriate to maintain sperm motility and function during both liquid storage and cryopreservation.