Recent developments of a Ki67 antibody to recombinant parts of the Ki67 nuclear antigen have provided a marker for tumor proliferation. In the present study, biopsy specimens were obtained from 20 patents with squamous cell carcinoma of the oral cavity at various sites, who also received a regional neck dissection. The patients' mean age was 61 years. Normal mucosa obtained from the surgical materials of 10 patients with a non-tumor condition was also examined as a control. The expression of Ki67 was examined immunohistochemically and the labeling index (LI) assessed in the biopsy specimens. The patients were divided into two groups; patient who already had a regional lymph node metastasis at the time of tumor resection and patient without any metastasis. All of the oral carcinoma and normal mucosa specimens were positive for Ki67, while the magnitude of staining showed a wide variation. The median LI of the patients with metastasis and without metastasis was 37.63±8.30 and 20.40±4.22 respectively, while the normal mucosa control was 7.62±1.70. The results of this study suggest that an immunohistochemical examination of the biopsy materials for the Ki67 antigen and assessed LI index should prove useful for the prediction of lymph node metastasis. (J. Oral Sci. 41, 53-56, 1999)
Guided tissue regeneration procedures using resorbable membranes have become accepted therapy for treating periodontal defects. Resorbable collagen and synthetic polylactide and polyglycolide copolymer membranes have been found to support regeneration and preclude the need for surgical removal. This study was undertaken to assess and compare the initial attachment of human gingival fibroblast cells to four collagen-based membranes (fascia lata, fascia temporalis, dura mater, and Type I bovine collagen) and a synthetic polylactic acid-based membrane (resolut®). Human gingival fibroblasts were grown from explants of normal tissue obtained during surgical reduction of retromolar tissues. Membrane specimens were placed in separate culture wells and incubated with fibroblasts for one hour. The number of adherent cells was evaluated by light microscopy using an ocular grid system and detailed examination was performed by scanning electron microscopy. The results of evaluation by light microscopy indicated that initial cell attachment was significantly less in the polylactic acid-based membrane group than in the collagen-based membrane groups (P<0.01). However, no significant differences were found among the collagen membrane groups in terms of fibroblast attachment (P>0.01). Scanning electron microscopy examination of fibroblasts cultured directly on barrier membranes indicated that the collagen-based membranes appeared to facilitate cell attachment, whereas the polylactic acid-based membrane exhibited a morphology that was not conducive to attachment of human gingival fibroblasts. Based on these limited in vitro results, it appears that collagen-based membranes offer greater potential than polylactic acid-based membranes for guided tissue regeneration at surgical sites. (J. Oral Sci. 41, 57-60, 1999)
This paper evaluates the effects of treatment with a pumping technique and arthroscopic lysis and lavage, followed by rehabilitative training, on condylar head mobility of the temporomandibular joint (TMJ). We studied 32 TMJs in 19 patients suffering from chronic closed lock with severe adhesion. The results were compared between cases with adhesions concentrated in two areas : mostly in the posterior and/or the anterior synovial portion of the upper TMJ compartment (11 joints) and mostly around the eminence (21 joints). The results showed a statistically significant improvement in condylar head movement for both groups between the initial and final stages of treatment. However, the results also suggested that patients with adhesion concentrated around the eminence are less likely to recover condylar head mobility to the same extent as those in the other group. (J. Oral Sci. 41, 61-66, 1999)
Radon-222 is a natural, gaseous, radioactive nuclide released from the ground and building materials into the air. Radon and its daughter nuclides can be an important disturbance factor for the measurement of environmental radioactivity. Radon concentrations in air in a radiation laboratory were measured with PICO-RAD detectors, which directly adsorb radon gas on activated charcoal. Generally, radon concentration increased in the absence of ventilation; a high concentration was observed in a radioisotope storage room without ventilation. Concentrations were low in other rooms used for experiments and measurement, which suggests that the radiation control practice in this laboratory is satisfactory and that the influence of natural radon gas on the measurement of radioactivity is negligible. (J. Oral Sci. 41, 67-69, 1999)
This study aimed to determine the effect of xylitol on the development and remineralization of caries in vitro, and to compare this effect with that of fluoride alone and in combination. Two experiments were devised. In experiment 1, bovine incisors were each sectioned into 4 portions which were randomly assigned to 4 demineralizing agents : A) acidic buffer (x), B) x+0.5 ppm fluoride, C) x + 20% xylitol, and D) x+20% xylitol+0.5 ppm fluoride. Caries-like lesions were produced in specimens. In experiment 2, carious lesions were produced in teeth. Five lesion-bearing slabs were cut from each tooth. While one was reserved as control (UN), others were randomly assigned to 4 remineralizing agents : 1) artificial saliva (y), 2) y+0.05 ppm fluoride, (3) y+20% xylitol, and 4) y+20% xylitol+0.05 ppm fluoride. Mineral loss (AZ) and lesion depth (ld) were quantified after 4-week remineralization. In experiment 1, numerical values of AZ and Id observed can be ranked as A>C>B>D. These differences were significant only in B and D when compared with A for AZ, but not between any group for ld. In experiment 2, the numerical values of AZ and ld for control UN (unremineralized) and remineralized groups (1-4) ranked as UN>3>4>1>2. Compared with UN, this difference was significant in all groups with ld, but not in any group with ΔZ. We concluded that tolerable levels of xylitol alone may not show a significant caries inhibiting and remineralizing effect, but may act as a caries inhibitor additively with fluoride. (J. Oral Sci. 41, 71-76, 1999)
The purpose of this study was to evaluate the effects of calcitonin administration on bone healing, following titanium implant insertion. Thirty adult New Zealand rabbits received one implant in each femur. Fifteen animals were randomized to provide test (calcitonin) and control (saline solution) groups. The animals were sacrificed 7, 14, 21, 28 and 42 days after the surgical procedure. The analyzed parameters were new endosteal/periosteal bone length, new endosteal/periosteal bone area and total cortical length. Considering treatment, histometric measurements showed significant differences (p<0.05) favoring the control group considering periosteal bone length and periosteal bone area, the other parameters were statistically similar between control and test groups. (J. Oral Sci. 41, 77-80, 1999)
Many studies have demonstrated the effect of various beverages on hard tissues of the mouth. Sugar consumption has also been avoided because it is associated with caries activity, and artificial sweetener research has been promoted. In this paper, data about the buffer capacity of black tea and yerba mate supplemented with sugar or one of two artificial sweeteners (Barny diet and NutraSweet) were examined. Salivary pH variations after the ingestion of both infusions were statistically analysed. A factorial design of four variables (Infusion, Sweetener, Concentration and Time) and their effects were considered independently and combined. The addition of sucrose lowered the pH of the infusions while black tea showed a greater buffer capacity than yerba mate. Significant differences (p < 0.0001) were obtained when salivary pH values were compared between infusions supplemented with sugar or artificial sweeteners. When a factorial design was used to examine differences between Barny diet and NutraSweet, no significant two-or three-way interactions could be observed. This statistical analysis showed a small significant variation in salivary pH after the ingestion of black tea or yerba mate with sugar but not with artificial sweeteners at the recommended concentrations. (J. Oral Sci. 41, 81-85, 1999)
The aim of this study was to compare the degree of osseointegration around titanium screws placed into the areas between guided bone augmented sites and guided bone graft augmented sites in 8 Japanese white rabbit tibia. The skin and periosteum were incised and lifted to expose the inner surfaces of both tibia. Eight rabbits were divided into 2 groups : 1) a guided bone augmentation (GBA) group of 2 rabbits, and 2) a guided bone graft augmentation (GBGA) group of 6 rabbits. In the GBA group, the bone marrow was penetrated several times in both tibial bones. Three titanium screws were inserted into the bone so that the top of each screw was 3 mm above the bone surface and covered with an expanded polytetrafluoroethylene membrane (ePTFE). In the GBGA group autogenous cortical bone (10 mm×10 mm×1 mm) was taken from the left tibia and grafted on the inner surface of the right tibial bone, titanium screws being similarly inserted. The surgical site was covered by ePTFE. After healing for 2 months, the animals were euthanatized, and the experimental area was prepared for histological investigation. New bone had formed on the surgical sites in the GBA group and grafted bone had survived in the GBGA group, with no sign of infection or membrane exposure. The degree of osseointegration around the screw was 67.6±11.2% (mean±SD) in the GBA group and 78.8±11.9% in the GBGA group. There was no significant difference between the groups (p=0.29). The ratio of mineralized bone to bone marrow was 45.7±6.2% in the GBA group and 64.4±4.4% in the GBGA group. There was a significant difference between the groups (p < 0.05). Although there was no significant difference for osseointegration around the screw placed into the GBA and GBGA sites, the quality of newly generated bone or grafted bone was quite different. Therefore, we suggest that predictable bone augmentation beyond the bone surface can be achieved by either the GBA or the GBGA procedure with ePTFE. However, it was difficult to conclude which procedure was superior with respect to the osseointegration around the titanium screw. (J. Oral Sci. 41, 87-92, 1999)
The nature and etiology of so-called simple bone cyst (SBC) are still a subject of debate. Our comprehensive review of the literature suggests that SBC, which appears histologically to be a single entity, has different natures and etiologies, resulting in divergent clinical features. In addition, an interesting case of mandibular SBC in an 11-year-old girl is presented with details of radiographic changes over a 7-year period. Fully documented patient records revealed that this lesion originated in the apical area of the first molar and took about 4 years to develop into a clinically evident bony expansion. (J. Oral Sci. 41, 93-98, 1999)
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