Objective : To study Ki-67 expression in relation to proliferative status in leukoplakia with mild dysplasia, well-differentiated squamous cell carcinoma, and healthy oral mucosa.
Study design : Sections from 20 cases of leukoplakia with mild dysplasia and 20 cases of well-differentiated squamous cell carcinoma that were histologically confirmed were stained with MIB-1 antibody using an advanced polymer staining system. Quantification of the immunopositive cells was performed using an image analyzer. The Ki-67 labeling index was expressed as the ratio of the number of cells stained by MIB-1 to the total number of cells counted per section (minimum of 1000 cells in consecutive fields).
Results : The mean Ki-67 labeling index score was 8.47±1.586 in healthy oral mucosa, 25.5±3.01 in premalignancy, and 29.7±3.04 in squamous cell carcinoma.
Conclusion : The antibody MIB-1 represents a robust and easily applicable marker of cell proliferation whose expression correlates well with the disease progression from premalignancy to malignancy.

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The development of mammalian tooth cusps or ridges has been explained by phylogenetic homology, such as the ‘Tritubercular theory’ (Gregory 1934). However, descriptions of the incisor and canine are lacking, and many questions remain unanswered. In this paper, the authors examine crown development in human teeth in embryos and skulls of young children by micro computed tomography (μ-CT), and discuss these problems. The results were as follows :
1) In milk incisors and canines, the first swelling developed into the central marginal ridge, and new swellings became mesial and distal sites and also buccal and mesial sites. Mesial and distal prominences developed into mesial and distal mamelons, but labial and lingual swellings formed cingulums.
2) In upper first milk molars, the first swelling developed into a buccal cusp and new swellings around it became buccal and lingual, and also mesial and distal sites symmetrically. The lingual prominence formed a lingual cusp, and the mesial and distal prominences formed mesial and distal cones or marginal ridges, but only the labial prominences developed into a mesio-buccal ridge.
3) In lower first milk molars, the first swelling developed into a buccal cusp, and new swellings became mesial and distal, and also buccal and lingual sites symmetrically. The lingual prominence developed into a lingual cusp. The mesial ridges and conules developed from the mesial prominence, and the distal prominence developed into three cones known as hypoconids. The buccal prominence developed into a mesio-buccal ridge similar to the first upper milk molars.
4) In upper second milk molars, the first swelling developed into a mesio-buccal cusp, and new swellings formed in the mesial and distal, and also buccal and lingual sites symmetrically. The lingual prominence developed into a mesio-lingual cusp, and the distal swelling into a disto-buccal cusp. The mesial prominence developed into mesial cones or mesial ridges, and the buccal prominence developed into a cingulum or a mesio-buccal ridge. Next, the disto-lingual cusp formed from a distal extension of the mesio-lingual and disto-buccal cusps.
5) In lower second milk molars, the first swelling developed into a mesio-buccal cusp, and new swellings spread mesially and distally, and also to buccal and lingual sites. The lingual prominence developed into a mesio-lingual cusp, the mesial prominence into mesial ridges, and the buccal prominence formed a cingulum or a mesio-buccal ridge. Subsequently, new swellings added two more mesial cusps, which developed into three hypoconids.
6) Many swellings appeared temporarily and then disappeared during the development process between and around those main cusps.
7) Stable main cusps or mamelons developed in wide spaces formed during jaw development. However, small swellings and invaginations of the crown, such as cingulums, marginal ridges and other structures, formed in narrow spaces of the jaw. The tooth and jaw morphogenesis have a close relationship.
8) Those developments suggested that the crown developed with symmetrical divergence patterns such as widening of concentric circular ripples. However, some of the new structures were inhibited by other factors. The authors dubbed this the ‘Divergence’ and ‘Convergence’ processes of tooth morphogenesis. These patterns originated in mammalian evolution.
9) This fundamental developing pattern of the crown is the same in both the upper and lower, and also the right and left sides of jaws.
10) All structures could be understood from the symmetry in ‘Divergence’ and ‘Convergence’ factors.

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Histopathological and immunohistochemical studies were conducted to elucidate the characteristics of nevus cells that accumulate in intramucosal nevi in the oral mucosa, primarily focusing on the maturation and origin on these cells. Twelve cases (5 men, 7 women ; mean age : 29.8 years) of intramucosal nevi were examined, with the most frequent site being in the gingiva. Macroscopically, Miescher's nevi were seen more frequently than Unna's nevi. Intramucosal nevi were characterized by a proliferation of nevus cells only within the underlying connective tissue, exhibiting maturation but not neuroid differentiation. From the immunohistochemical analysis of the nevus cells, staining for S100, Melan-A, and MITF was stronger in A-type cells than in deeper B-type cells, although B-type cells along the edge of the nevus cell nest exhibited moderate positive for S100, Melan-A, and MITF. Positive cytoplasmic expression of c-Kit was scattered in B-type cells deep within the lesion and in mast cells surrounding the blood vessels around the nevus cell nest. These results and a review of the literature suggest that nevus cell formation begins with the proliferation of melanocytes and their migration into the submucosa with a concomitant loss of cell adhesion. Nevus cells exhibited decreased melanocytic development with the depth of the lesion. However, along the edge of the lesion, B-type cells exhibited melanocytic but not neuroid differentiation. Thus, maturation of nevus cells could be a form of adaptation to the surrounding environment.

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The prevalence rate of amlodipine-induced gingival overgrowth was determined in patients taking amlodipine for three months. Gingival overgrowth was found in four cases among the 301 patients surveyed ; a prevalence rate of 1.3%. The clinical findings of amlodipine-induced gingival overgrowth were similar to those induced by other calcium channel blockers.

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Proper understanding of the orofacial development and deformities associated with various syndromes is important for planning appropriate dental treatment and improving the craniofacial features. However, it is quite difficult to take cephalometric radiographs of patients with severe mental retardation or behavioral disorders, since patient co-operation and stability of body movement are necessary while taking the radiographs. Computed tomography (CT) is potentially a better tool for the diagnosis and treatment planning of complex maxillofacial deformities than conventional lateral cephalograms. CT images of patients with mental retardation can be taken under general anesthesia. The absorbed dose of radiation in 128 slice multi-detector row computed tomography (MDCT) used in this study is established as CTDI vol. 17.24 mGy, which is less than that of conventional CT (65 mGy). However, the use of MDCT for cephalometric analysis in pediatric dentistry has not been reported. Hence, the aim of the present study was to compare the reliability and difference of angle and linear measurements of craniofacial form using the landmarks on conventional and MDCT lateral cephalograms of human skulls. The results of this study showed that angular and linear measurements recorded from conventional and MDCT lateral cephalograms were similar. In conclusion, there were no significant differences in the mean and standard deviation of angular and linear measurements between conventional and MDCT lateral cephalograms of human skulls. Angular and linear analysis on MDCT cephalogram might show good precision for craniofacial analysis.

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In pediatric dentistry, examination of the development of crown or tooth root is essential to determine the physiological development age. Measurements of the tooth size and dental arch width are also required to predict normal occlusion and oral function, and to plan appropriate dental treatment. Some dental anomalies are keys to identify congenital malformation syndromes. In patients with behavioral disorders, it is quite difficult to take diagnostic dental models and pantomographs, since patient co-operation and stability in body movement for a few minutes is necessary while taking the dental impression and pantomographs. For patients with severe mental retardation and behavioral disorders, performing computed tomography under general anesthesia or deep sedation is easier than taking pantomographs while awake. The aim of the present study was to compare the tooth development stage on pantomographs and mesiodistal diameter measurements of tooth size and dental arch width of dry human skulls with the images of those on 128 multi-detector row computed tomography (MDCT). Based on the results, the measurements of tooth development stage, tooth size and dental arch width on MDCT images were clinically precise.

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Heat shock proteins (HSPs) play an important role in maintaining protein homeostasis within the cell, and they are also related to inflammation. However, it is not clear how HSPs regulate inflammatory cytokines in periodontal ligament (PDL) cells during mechanical stress. The present study focuses on the expression of HSP70 in the PDL during experimental tooth movement in rats. A total of 35 6-week-old male Wistar rats were subjected to orthodontic force of 10 g to induce mesial tipping movement of the upper first molars. Experimental tooth movement was accomplished for 14 days. We determined the expression of HSP70 proteins in the PDL during orthodontic tooth movement by immunohistochemistry. HSP70 immunoreactivity was detected in PDL fibroblasts on the compressive side by an orthodontic force of 10 g. On day 1 after tooth movement, the immunoreactivity of HSP70 was weak. On days 2, 3 and 4, we identified a greater positive reaction for HSP70 in the nucleus of fibroblasts than that recognized on the first day. The HSP70-positive reaction further increased on days 7 and 14. From our quantitative evaluation, the rate of HSP70-positive PDL fibroblasts significantly increased compared with control fibroblasts, and this occurred in a time-dependent manner. Therefore, HSP70 may function as a homeostatic factor to compensate for PDL-cell changes that occur during orthodontic force.

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X-ray phase-contrast imaging and X-ray absorption analysis, including X-ray absorption fine structure (XAFS) analysis, were carried out using parametric X-ray radiation (PXR), which has unique characteristics such as monochromatic wavelength-tunable highly coherent X-ray radiation, generated at the Laboratory for Electron Beam Research and Application (LEBRA), Nihon University. Diffraction-enhanced imaging, a kind of phase-contrast imaging, was carried out using whole and sectioned teeth, a mouse kidney, and chicken and quail eggs. The obtained images showed some specific features that would be scarcely detected by other techniques. X-ray absorption edge analysis was applied to elemental analysis such as detecting arsenic in soil samples and strontium in fossil eggshells. A trial of XAFS was successfully carried out for metals and alloys. In this study, LEBRA-PXR was verified as a powerful and high ability X-ray source for X-ray phase-contrast imaging and absorption analysis, not only for hard tissues but also for soft tissues.

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Oral submucous fibrosis (OSMF) is well recognized as one of the most common potentially premalignant conditions of the oral mucosa in India related to chewing of areca nut products and characterized by mucosal rigidity of varying intensity caused by fibroelastic changes of the juxta-epithelial layer, resulting in a progressive inability to open the mouth. The present study aimed to measure submucosal thickness by high frequency ultrasonography (USG) in cases and controls and to correlate this with clinical and histological severity of the disease. We conducted a hospital-based cross sectional study of 20 subjects who were clinically and histopathologically proven to have OSMF (cases) and 20 controls matched for age, sex and body mass index. Transcutaneous imaging of the buccal and labial submucosa was performed and the values were correlated with clinical stage and histological grade of the disease. Cases had increased submucosal thickness when compared to controls at all measured sites. The echogenicity pattern of cases showed areas of irregular hyperechoic linear streaks due to fibrotic submucosal deposits. In contrast, the submucosa of controls appeared as a hypoechoic band. To the best of our knowledge, this is the first study to use USG to measure the thickness of submucosal fibrosis in OSMF.

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The term “en coup de sabre” is used for linear scleroderma located in the temporoparietal region that produces sharp bordered furrowing with alopecia when extending to the scalp. Although it is a benign disease, the resultant marked deformity often necessitates treatment. While in some cases atrophy is confined to the skin and subcutaneous tissue, cases with underlying muscle and bone involvement have also been reported. Symptoms and clinical findings in linear scleroderma of the face show variations. We present a case of “en coup de sabre” linear scleroderma of the cheek affecting only the skin and subcutaneous fat tissue without any accompanying disorder.

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Desmostylian remains including Desmostylus and Paleoparadoxia have been reported from Miocene (5 to 20 Ma : Mega annum) deposits in Japan and along the west coast of the North America. In this report, we describe the histological characteristics of a Paleoparadoxia incisor.

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