The aim of this study was to three-dimensionally observe the distribution and the arrangement of fiber system in fibrous walls around the temporomandibular joint and to examine structural differences between the medial and the lateral fibrous capsules and the dynamic characteristics. The tissues without destructive changes were obtained from human cadavers aged 60 years to 90 years.
The elastic fiber staining and KOH-collagenase treatment were performed to observe the arrangement and the distribution of elastic fibers. The three-dimensional arrangement of collagen fibrils was revealed by KOH-Triton-trypsin treatment.
Although elastic fibers in the capsules arranged almost parallel to collagen fibril bundles, they were thick and irregularly branched off in the boundary between the articular disc and capsules.The capsules consisted of many blood vessels and fatty tissues, collagen fiber bundles, and a lump of elastic fibers around the junction of the articular disc. These structuers seem to provide some elasticity to resist the tensile stress. A fibril bundle was more densely packed in the lateral than in the medial of the fibrous capsule. As leaving it from the disc, the fibril bundles appeared to be dense, and became anteroposteriorly or mediolaterally oriented. Minutely the fibril bundles took the form of a simple linear, meandering or spiral appearance and a stack of lamella, as in the disc and retrodiscal tissue. The existence of meandering or spiral fibril bundles and interfibriller elastic fibers may be involved with flexibility of the capsules when the disc anteroposteriorly slides.

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It is well known that the application of physiological mechanical stress to skeletal tissue is important in regulating bone remodeling and modeling. The aim of this study is to examine the expression of Na⁺/Ca²⁺ exchanger (NCX1) mRNA and the activation of stretch-activated (SA) Ca²⁺ channels when three-dimensional strain is applied to osteoblast-like cells (MC3T3-E1 cell). The cells were mixed with collagen solution at a cell density of 6×10⁵ cells/ml and layered on nylon mesh, then pre-incubated in αMEM containing 10% fetal bovine serum. After 24 hours of pre-incubation, cells in the collagen gel were incubated for up to three days with or without intermittent mechanical stimulation (1 Hz, 10% stretch, 15 min, three times a day) in the presence or absence of Gd³⁺, an inhibitor of SA channel. The expression of NCX1 mRNA was assessed using RT-PCR, and cells were examined using a confocal laser microscope after visualizing actin filaments using rhodamine-phalloidin staining. Accelerated NCX1 mRNA expression was observed in the stretched cells. The mechanical strain also caused the cells to change shape and orient perpendicular to the direction of stretching. Consistent with the morphological changes of the cells, strong intensity of the staining for actin filaments was observed in the stretched group, which was abolished by the addition of Gd³⁺. Our results suggest that the mechanical strain induces the Ca²⁺ influx through activation of the SA channel and NCX1 resulting in the morphological changes in osteoblastic cells.

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Lymph nodes are small organs occurring in series along the course of lymphatic vessels. The parenchyma consists of a highly organized accumulation of lymphoid tissue, which recognizes antigens in the lymph and builds up a specific immune reaction against them especially in lymphoid follicles. Afferent lymphatic vessels come from the relatively huge area in the body and enter the node at multiple sites over its convex surface. Therefore, in this study, we investigated whether the parenchyma of the node is restricted by the afferent vessels. Two different colored tracers, inks (black and red) or fluorescent dyes (AlexaFluor^® 488/594) , were subcutaneously injected in the tongue and gingiva of mice. At the indicated time, submandibular lymph nodes were dissected and examined under light and/or fluorescent microscopy. Injection of 0.1 ml of a tracer at 1 h showed that the tracers entered into the whole area of the node whereas a 0.02 ml injection showed that traces localized some restricted area in the node. The lymph node at 1 h after the injection of two tracers showed that both traces penetrated into different parts of the node. Furthermore, at 48 h two different tracers were detected at the different follicles. These results indicated the regional restriction of lymphoid follicles in the node which might be regulated by the different site of afferent vessels to the node and suggest that each of the lymphoid follicles in a node respond to different antigens.

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The cervical defect (CD), the so-called wedge-shaped defect in Japan, or the non-carious cervical tooth lesion of human permanent teeth may be eroded by cross tooth-brushing with and without occlusal stress, or by attachment of dental clasp for a long time. Such a CD occasionally causes dentin hypersensitivity although the reparative dentin (RD) is deposited towards the dental pulp cavity. However, the correlation of a CD and the RD in volume has not been elucidated yet except for the difference of their areas on the ground sections reported previously. In this study, we analyzed the area and volume correlations of a CD and the RD in each teeth (n=10) by micro CT analysis. The area ratio (RD/CD) was 72.4±28.6 % (r=0.856, p<0.01) on the longitudinal cut plane showing the maximum areas of a CD and the RD, which were similar to those of the ground section assumed longitudinal central line of a tooth. On the other hand, the volume ratio (RD/CD) was 18.0±8.2 % (r=0.792, p<0.01). Therefore, it is clearly illustrated by micro CT analysis that the volume ratio (RD/CD) should be extremely lower than the area ratio in the longitudinal X-ray slices and also the ground sections previously reported. As the clinical consideration, the RD formation will be alleviated dentin hypersensitivity. On the basic observations, it was accuracy illustrated that micro CT analysis was useful for the volume measurement of the RD as well as the CD.

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Recently, there has been an increase in the application of dental implants in maxillofacial prosthesis due to the degree of difficulty involved in such prosthetic treatment in comparison with general partially edentulous treatment. Zygomatic implants are recognized to provide a high degree of orofacial function recovery in cases of extensive maxillary defects, and thus contribute to improvements in QOL. The present report introduces the use of zygomatic implants and a duplicate of an existing prosthesis for the efficient fabrication of a maxillofacial prosthesis with superior function in the treatment of extensive maxillary defects.
The patient was a 46-year-old male, who initially presented with squamous cell carcinoma of the maxillary anterior region. After radical surgery for squamous cell carcinoma, a prosthesis for the resulting maxillary defect was inserted using the remaining teeth as abutments. Later, the prosthesis became unstable due to loss of the remaining teeth. To solve this problem, an implant-supported prosthesis using zygomatic implants was planned. It is important to provide a superstructure which does not interfere with esthetics and speech. Therefore, the position of the implant body, the circumoral tissues, the extent of rehabilitation of the palatal defect and midfacial support, and the maxillomandibular relationship should be simultaneously recorded. A duplicate of the existing prosthesis provided a standard, and was used for impression taking and maxillomandibular registration.
Using this technique, a prosthesis which allowed effective mastication, speech, and other orofacial functions was efficiently fabricated.

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Occlusal management for cleft palate patients often lasts a long time, starting in the growth phase. Guidance of jaw development is required, because many factors, including lip and palate surgery, can cause undergrowth of the maxilla. We report herein the case of a patient who underwent long-term monitoring of maxillofacial growth and development, occlusal control and surgical correction from childhood to adulthood, with favorable final outcomes. Maxillofacial growth and development and therapeutic effects are discussed. The patient was a woman with bilateral cleft lip and palate (incomplete on the left). Occlusal management was started at 4 years old. After the end of pubertal growth, she underwent upper right lateral incisor and lower bilateral premolar extraction at another hospital, as visiting our hospital was difficult. During retention, she showed progenia and openbite due to relapse. Skeletal mandibular protrusion due to maxillary undergrowth was diagnosed and surgical correction was performed by maxillary and mandibular osteotomies. The canine was placed in the right cleft defect, and occlusion was established non-prosthetically as a reduction of the dental arch, obtaining favorable results. To evaluate therapeutic effects, maxillofacial growth and development were evaluated longitudinally. Maxillary growth and development were based mostly on inferior components, and anterior growth was basically absent. Although occlusal management was started in early childhood, anterior maxillary growth guidance was not performed. Since maxillary growth is often marked in patients with cleft lip and palate showing normal overjet during the growth phase, improving overjet from the first examination is important.

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This is a case report of a female patient who was 15 years and 2 months old when first examined and who complained about anterior crowding. The patient had angle class III malocclusion accompanied by congenitally missing mandibular central incisors on both sides, telescopic occlusion at the second molars, and proclination of the maxillary incisors.
The orthodontic treatment involved edgewise appliances, and a Nance holding arch with extraction of the maxillary first premolars (both sides). Treatment involved arranging the lateral incisor as the central incisor, the canine as the lateral incisor, and the first premolar as the canine in the lower dental arch. When aligning the canine as the lateral incisor, it is common to avoid cuspal interference by reforming the cusp of the canine. However, we were eventually able to avoid cuspal interference by performing tooth movement only, and achieved good functioning when guiding the lateral excursive and protrusive mandibular movements without interference.

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We report a case of sublingual dermoid cyst which painlessly enlarged to a diameter of over 50 mm. A 29-year-old woman was noted to have a swelling of the mouth floor during treatment at a local dental clinic, and was referred to our department on June 18, 2009. On initial examination, a painless, elastic, soft swelling of the mouth floor was noted, presenting with the appearance of a double tongue. Intercuspation was possible, and tongue movement, articulation, and eating were not impaired. The patient experienced dyspnea at bedtime. T2-weighted MRI revealed a 50×30×30- mm oval, well-defined, cystic lesion with a strongly hyperintense border and heterogeneously hypointense interior. She underwent intraoral cystectomy under general anesthesia on September 4, 2009. Tracheal intubation and sedation were maintained because of the fear that postoperative airway stenosis might develop due to swelling of the oral floor, and the patient was followed-up. It was histopathologically diagnosed as a dermoid cyst.

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We report here a case of skeletal Class III malocclusion with mandibular prognathism treated with a combination of orthodontic and orthognathic surgery. A 28-year-old woman presented with a cross bite and the inability to incise food; she had no history of trauma or serious illness. She was diagnosed with a skeletal Class III malocclusion and crowded teeth. The left mandibular first molar showing an inappropriate root canal treatment was extracted and the left mandibular third molar was implanted into the first molar extraction space. She was treated with conventional fixed edgewise appliance therapy combined with orthognathic surgery (sagittal split ramus osteotomy). The mandibular prognathism was eliminated. The transplanted tooth remains stable more than 5 years after the procedure.

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In skeletal mandibular prognathism, we often provide combined treatment involving an orthodontic approach and a surgical technique. However, there is currently no clear basis for whether we apply a surgical operation. We selected two similar cases based on their skeletal morphological characteristics, dentition alveolar characteristics and facial appearances. One patient received treatment by an orthodontic approach alone, while the other patient was treated by combined orthodontic and surgical approaches. In the orthodontic treatment alone, we treated the patient with a multibracket appliance after extraction of the upper and lower premolars on both sides. In the combined orthodontic and surgical treatments, we used a pre-surgical orthodontic, performed a setback operation of the mandible, and used a post-surgical orthodontic treatment with genioplasty. After the orthodontic treatment alone, the patient could take on the proper overbite by lingual inclination of the lower anteriors, but exhibited a gingival recession in his lower labial anteriors owing to excessive lingual inclination out of the symphysis. In contrast, after the combined surgical and orthodontic treatments, the patientʼs inappropriate maxillomandibular relationship was greatly improved. Her gingival recession at the initial visit was improved by liability relief of the periodontal tissue because the proper interincisal angle could be obtained. Based on these results, we investigated the symphysis morphological characteristics and compared the differences in the lower incisive inclinations in the two patients. Furthermore, we considered the differences from the esthetic, periodontal and occlusal functional viewpoints.

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The indication for surgical reduction versus non-surgical treatment of mandibular condylar fractures remains controversial. Non-surgical treatment of displaced condylar mandible fractures may lead open-bite deformity or malocclusion caused by shortening of the mandibular ramal height. On the other hand, transbuccal open reduction and fixation of the condylar fractures may induce surgical complications, such as risk of facial nerve injury and creation of visible scars. To avoid these complications, we performed endoscope-assisted transoral open reduction and miniplate fixation to three patients with the condylar fractures. Even the transbuccal stab incisions and the use of trochars were not needed in this method. One year after the operation, limitation of mouth opening or malocclusions were not observed in all patients.

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[in Japanese]

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[in Japanese]

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