Accessory Mental Foramen Misdiagnosed as Radiolucent Tumour by Conventional Dental Radiography

The mental foramen is an important landmark for identifying the mental nerve, and the accessory mental foramen is a rare anatomical variation. This article describes the use of computed tomo- graphy (CT) to detect an accessory mental foramen that was initially misdiagnosed as a radiolu- cent tumour in the right premolar region of a 39-year-old woman by panoramic radiography. The case suggests that preoperative CT should be performed to detect any anatomical variations. This knowledge would help in diagnosis, preoperative planning and prevention of intraoperative nerve or vascular injury.

A Pilot Study of Antibody Drug Therapy to Regulate Cell Adhesion in Dental Implants

Dental implant therapy is a highly effective treatment for recovering occlusion after tooth loss. An important factor in the success of dental implants is establishing strong osseointegration. If more epithelial cells migrate to the implant-bone interface than mesenchymal stem cells, effective osseointegration may fail. Therefore, controlling epithelial cell adhesion and motility would be an effective strategy to increase the success rate of osseointegration. Laminin-332 is a major component of the basement membrane and is composed of three chains (α3, β3 and γ2). It is well-known that laminin-332 regulates cellular functions such as adhesion, proliferation, apoptosis and differentiation. These biological functions depend on changes in the structural arrangement of laminin-332 by proteolytic cleavage. It is well-known that cleavage of the α3 chain between its LG domains gives laminin-332 its biological function. In this study, we focused on LG domain cleavage and developed antibodies that target the LG domain cleavage site. We attempted to change the biological function of laminin-332 to control cell adhesion for the purpose of regulating dental implant therapy.

Multifactorial study of mobile phone dependence in medical students: Relationship to health-related lifestyle, Type A behavior, and depressive state

We investigated factors contributing to mobile phone dependence. To 139 medical students, we administered a self-reporting questionnaire designed to evaluate mobile phone dependence, health-related lifestyle, patterns of behavior, and depressive state. Multivariate logistic regression analysis revealed that scores for poor health-related lifestyle, Type A behavior pattern, and presence of depression are independently associated with degree of mobile phone dependency. These findings suggest that persons with an unhealthy lifestyle, Type A behavior traits, or depression might benefit from mobile phone use guidance.

Relationships of loneliness and mobile phone dependence with Internet addiction in Japanese medical students

We investigated factors contributing to Internet addiction in 105 Japanese medical students. The subjects were administered by a self-reporting questionnaire designed to evaluate demographic factors, Internet addiction, loneliness, health-related lifestyle factors, depressive state, patterns of behavior, and mobile phone dependence. Results of multivariate logistic regression analysis indicated that loneliness and mobile phone dependence were positively related to degree of addiction. Our findings suggest that Internet addiction is associated with loneliness and mobile phone dependence in Japanese students.

The effectiveness of local anesthetic and sodium hyaluronate injection for the posterior disc displacement: A case report

Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint of abnormal occlusion. Regarding the present status, there was no occlusion on the right side. No temporomandibular joint pain, myalgia, or clicking were observed while mouth opening. On MR images, the posterior disc displacement without reduction on the right was observed and it was assumed that occlusal abnormality was due to this condition. We treated him with the following methods. After injection into the superior articular cavity with 2% lidocaine, a sodium hyaluronate preparation was injected followed by intermaxillary traction applied using rubber. The recovery of occlusion was confirmed in follow-up at 5 days after treatment. In the 13th days, the intermaxillary traction was removed. On MR images, the right disc condition was changed to anterior disc displacement with reduction. We consider our treatment methods are effective for this clinical condition.

Hard Tissue-Forming Ability and Ultra-Micro Structure of Newly Developed Sponges as Scaffolds Made with Sodium Alginate Gel and Chondroitin Sulfate

To regenerate teeth and bones, a scaffold is essential. Hydroxyapatite has been used in many studies, but scaffolds made of hydrogel or sponge are also effective. The hardness of hydroxyapatite is a disadvantageous property for shaping. A sponge is suitable as a scaffold because the shape of the scaffold can be matched to the defect. Sodium alginate (AL) has excellent biocompatibility and a sponge can be made from this gel by lyophilization. The purpose of this study was to promote hard tissue formation with a sponge made of AL gel or AL gel and chondroitin sulfate (Chs). Sponges were made from AL gel, which were then used as a scaffold to investigate their effectiveness for the formation of hard tissue or bone. Hard tissue formation in the pores of these AL sponges was estimated in vitro and in vivo. In the sponge made from AL gel, the concentration of AL and the addition of Chs affected bone formation. Concentration of AL would affect the shape and size of the pores. ALP activity in the sponges was also enhanced by Chs. The amount of osteocalcin (OC) produced in the sponge by rat bone marrow cells increased depending on the AL and Chs concentrations in the gel. The level of OC amount in the sponges made from AL gel containing Chs was notable in vivo. Bone formation in the sponge in vivo was affected by the addition of Chs in AL gel. The quantity of OC and the bone formation in AL sponges in subcutaneous tissue in vivo suggested that AL sponges can be useful as a scaffold.

Hybrid Scaffolds Composed of Amino-Acid Coated Sponge and Hydroxyapatite for Hard Tissue Formation by Bone Marrow Cells

A formalin-treated polyvinyl-alcohol (PVF) sponge is convenient as a scaffold because its configuration is easily modified. However, coating the sponge with an adhesive chemical agent is necessary to attach bone marrow cells (BMCs) to the sponge structure. Moreover, it was considered that a hybrid scaffold composed of a sponge and enveloped cylindrical porous hydroxyapatite (HA) would be convenient. In this study, the effect of leucine (Leu) coating on a PVF sponge was examined for osteogenesis on an HA/PVF hybrid scaffold by rat BMCs (rBMCs). In an in vivo assessment, the sponge immersed in Leu solution (10 mg/ml) was inserted into the hollow center of cylindrical HA. The sponge received 1.5 × 106 rBMCs obtained from male Fischer 344 rats. The hybrid scaffolds were then implanted subcutaneously of syngeneic rats for 6 weeks. In vitro assessment of Leu to hard tissue formation with coating on the well or addition in rBMC culture medium was also performed in a 6-well plate for 2 weeks. In vivo examinations showed the excellent effect of Leu coating on PVF sponge. Leu-coated PVF sponge in the scaffolds showed marked new bone formation in the pores by histological examination. Leu-coated PVF sponge showed a high quantity of osteocalcine (OC). HA might prevent the release of rBMCs from PVF as a barrier. In in vitro examinations, the quantity of OC in rBMC culture with and without the addition of Leu in culture medium showed no significant difference. However, addition of Leu showed significant ALP activity level in culture medium. Leu coating in culture plate wells showed no influence on the quantity of OC. It was concluded from the results that Leu might prevent the emigration of rBMCs to the outside of the scaffold and promote the differentiation of cells to osteoblasts in the scaffold.

Bone Formation in a Scaffold Composed of Cylindrical Hydroxyapatite and Tryptophan- or Lysine-Coated Sponge <i>in Vivo</i>

Because of the three-dimensional structure of bone or hard tissue such as a tooth, a scaffold is necessary for its regeneration by cellular engineering. Commonly, for in vivo examination, hydroxyapatite (HA) has been used as such a scaffold. Cylindrical HA with a hollow center, which included a columnar formalin-treated polyvinyl alcohol sponge, was used in this examination as a scaffold. The sponge had been coated with L-tryptophan or L-lysine before insertion into the hollow center of the HA. Rat bone marrow cells (rBMCs) derived from the femur were seeded in the sponge before insertion into the hollow center of HA. The number of rBMCs seeded in each sponge was 1.5 × 106. These scaffolds were implanted subcutaneously into the backs of Fischer 344 rats for 6 weeks. In the amino-acid-coated sponge in HA, osteogenesis was found histologically. An osteocalcin level of approximately 10 ug was measured in the scaffolds with L-tryptophan-coated formalized poly-vinyl alcohol sponge containing rBMCs, 4 ug on average in the scaffolds with L-lysine-coated sponge containing the cells and about 2 ug in each scaffold with uncoated sponge containing the cells. The structure of the scaffolds used in this study was thought to be suitable for osteogenesis by rBMCs. It was concluded that tryptophan, as a factor for bone formation by stem cells, functioned by promoting cell adhesion and the differentiation of stem cells into osteoblasts.

Calcified Nodule Formation <i>in Vitro</i>Using Rat Mandibular Incisor Pulp Cells

One great advantage of bone marrow is that a large number of stem cells can be obtained. However, stem cells cannot be taken from the bone marrow of a patient for the purpose of regenerating teeth. In dental practice, it may not be practical to obtain mesenchymal stem cells for the regeneration of the tooth from iliac bone marrow, as in orthopedics. Therefore, establishment of a cell source for tooth regeneration is one of the important problems in the field of regenerative medicine. Although the isolation of undifferentiated mesenchymal stem cells or odontoblasts from dental pulp may be difficult, dental pulp may be a favorable source for stem cells to regenerate a tooth via tissue engineering. As a fundamental study for tooth regeneration, this study was performed in order to clarify the culture periods for proliferation and differentiation using rat dental pulp-derived cells. The results of this study were as follows: Primary culture of the dental pulp cells does not require a long period of time. However, for sufficient proliferation of dental pulp cells to form a calcified nodule in the secondary culture, a long culture period is required. Dexamethasone was essential for the formation of calcified nodules by dental pulp-derived cells. Calcified nodule formation by dental pulp-derived cells in vitro required more than one month. The duration of the secondary culture for the dental pulp-derived cells will be much longer.

A unique case of a calcifying cystic odontogenic tumor

The calcifying odontogenic cyst was first reported by Gorlin et al. in 1962. At that time, it was classified as a cyst related to the odontogenic apparatus, although it was later renamed as a calcifying cystic odontogenic tumor by the WHO calcification in 2005 due to its histological complexity, morphological diversity and aggressive proliferation [2]. Here, we describe a case of a calcifying cystic odontogenic tumor in a 4- year-old boy. The lesion was surgically removed, and the histopathological examination revealed it to be a cystic tumor with ghost cells, a stellate reticulum and small amount of dentinoid tissue in the cystic wall.

Effect of L-lysine in culture medium on nodule formation by bone marrow cells

The aim of this study was to estimate the effect of L-lysine on nodule formation by rat bone marrow cells in vitro. In this study, L-lysine was added to medium for mesenchymal stem cell culture to promote proliferation and differentiation of the cells, and then nodule formation was estimated in an in vitro rat bone marrow cell culture. Bone marrow cells from the bone shafts of the femora of Fischer 344 rats were cultured in minimum essential medium with 20 μl of L-lysine solution at 10﹣4, 10﹣5, 10﹣6, 10﹣7 or 10﹣8 M. Dexamethasone was also added to the medium at 10 nM for differentiation of stem cells from bone marrow into osteoblast progenitor cells. The subculture was performed for 2 weeks. The quantity of osteocalcin in rat bone marrow cell culture with dexamethasone was 392 ng/ml. In the medium with dexamethasone and 10﹣8 M L-lysine, the quantity of osteocalcin was 437 ng/ml. Nodules only formed upon addition of 20 μl of L-lysine at 10﹣8 M. It was indicated that 10﹣8 M L-lysine should be the optimal concentration for calcification. For nodule formation by rat bone marrow cells in vitro, the optimum concentration of L-lysine in culture medium might be 20 μl of 10﹣8 M. L-lysine could play an important role in matrix production for bone formation in vitro.

Effects of laminin on hard tissue formation by bone marrow cells <i>in vivo</i>and <i>in vitro</i>

The effect of laminin on hard tissue formation using rat bone marrow cells was assessed. Rat bone marrow cells were obtained from femora of 6-week-old male Fischer 344 rats. In this in vivo examination, porous cylindrical hydroxyapatite scaffolds with a hollow center were immersed in 100 mg/ml laminin solution and air-dried. Rat bone marrow cells in 200 ml culture medium at 1 × 106 cells/ml were seeded in the scaffolds. The scaffolds were implanted into the dorsal subcutis of 7-week-old male Fischer 344 rats for 6 weeks. The scaffolds were then removed and examined histologically. For in vitro examinations, 1 × 105 rat bone marrow cells in 2 ml culture medium were then cultured with the addition of dexamethasone and laminin. Rat bone marrow cells were also cultured in laminin-coated culture plates. In vitro examinations showed the effectiveness of laminin for hard tissue formation from the results of biochemical and immunochemical analysis. From the in vivo examination, laminin coating of the scaffolds induced hard tissue in the pores with the cells. It is concluded that laminin is useful for bone formation, as in an in vitro culture study using bone marrow cells, in hydroxyapatite scaffolds in vivo.

Increased Expression of 11<i>β</i>-Hydroxysteroid Dehydrogenase Type 1 in Experimental Periodontitis Induced by Lipopolysaccharide from <i>Porphyromonas gingivalis</i>

It has been proposed that 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which activates glucocorticoids, plays a role in chronic inflammatory diseases including metabolic diseases, rheumatoid arthritis, and ulcerative colitis. We have recently reported that the expression of 11β-HSD1 is increased in the gingiva of patients with chronic periodontitis and in that of rats with ligature-induced periodontitis. In this study, to further demonstrate the involvement of 11β-HSD1 in chronic periodontitis, the expression of 11β-HSD1 was investigated in another rat model of experimental periodontitis induced by intragingival injection of lipopolysaccharide from Porphyromonas gingivalis (LPS-PG). Alveolar bone loss was observed two weeks after intragingival injection of LPS-PG. The level of 11β-HSD1 mRNA assessed by real-time reverse transcriptase-polymerase chain reaction was significantly elevated in LPS-PG-induced periodontitis compared with controls. The expression of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which inactivates glucocorticoids, was not significantly different between control and LPS-PG-induced periodontitis. The expression of 11β-HSD1 was significantly correlated with that of TNF in LPS-PG-induced periodontitis. The increased expression of 11β-HSD1 protein in LPS-PG-induced periodontitis was confirmed by immunohistochemistry using anti-11β-HSD1 antibody. These results further suggest a role for 11β-HSD1 in the pathogenesis of chronic periodontitis.

In Vivo Estimation of Osteogenesis by Bone Marrow Cells in a Bi-Phasic Scaffold and in Each of Its Components

A bi-phasic scaffold consisting of a columnar formaldehyde-acetalized polyvinyl alcohol (PVF) sponge and a cylindrical porous hydroxyapatite (HA) with a hollow center was devised. Rat bone marrow cells (rBMCs) were seeded into the sponge placed in the hollow center of the cylindrical porous HA. The bi-phasic scaffold, a cylindrical porous HA and a PVF sponge separated from a bi-phasic scaffold after rBMC seeding, and a PVF sponge without rBMCs as a negative control, were implanted for 6 weeks into rat dorsal subcutaneous tissue. In each construct, bone formation was examined histologically and osteocalcin was measured immunochemically. Bone formation was observed in the bi-phasic scaffold and also in the cylindrical porous HA isolated from the bi-phasic scaffold. A significant difference in the quantity of osteocalcin was observed between the bi-phasic scaffold and the isolated cylindrical porous HA. No bone formation was found in the isolated PVF sponge. The bi-phasic scaffold as an outer layer of the scaffold seemed to inhibit the outflow of rBMCs from the PVF sponge. This type of bi-phasic scaffold may have two specific characteristics: Attachment of cells both in PVF sponge and cylindrical porous HA.

Vascular Malformation with Multiple Organized Thromboses in Buccal Region

Vascular malformations occur most frequently in the maxillofacial and oral regions. Although many cases of vascular malformations with phlebolithiasis have been reported, only few reports have documented cases of thrombosis formation. We report a rare case of a vascular malformation with multiple thromboses in the left buccal region. A 28-year-old woman had a painless swelling in the left cheek when she consulted our hospital. T1-weighted magnetic resonance imaging revealed a low-signal lesion, having the same intensity as the muscle, in the left buccal region, and T2-weighted imaging revealed a high-signal lesion. Additionally, three tuberous tumours were noted in this lesion showing both a light high signal on T1-weighted imaging and a low signal on T2-weighted imaging. Based on these imaging findings, as well as clinical and pathological findings, the patient was diagnosed with multiple vascular malformations in the left midfacial region. The three tuberous tumours showed necrotic tissue in the central area, which was formed by calcified and concentric fibrous tissue, and vascularization. Because tumorous lesion and typical vascular structure by the Elastica Van Gieson staining were not observed, these tumours were seemed that fibrin thrombus in this lesion formed the organized tissue.

Soft Tissue Recurrence with a Mucocele of an Intraosseous Ameloblastoma

Ameloblastoma is an odontogenic tumor of high frequency and usually occurs as an intraosseous growth. Ameloblastomas frequently recur, sometimes undergoing malignant transformation. These tumors are usually characterized as being multilocular, of the follicular type histopathologically, and invading strongly at the border region of the tumor. More than 10% p53-positive tumor cells give a prognostic indication for a tendency to recur. A recurrent ameloblastoma usually occurs in the intraosseous region near the site of the original lesion. In very rare cases, a recurrent tumor proliferates distantly from the original site in the soft tissue only. We report a rare case of recurrent ameloblastoma in the buccal mucosa with a mucocele that originated from the small salivary glands after the extirpation of an intraosseous (mandibular) ameloblastoma. We also performed a p53 immunohistochemical study of this recurrent tumor.