Although it is well known that crown cusps of teeth break through the covering oral epithelium at the final stage of tooth eruption, the detailed mechanism of jts process is still obscure. This study investigated the morphological and immunohistochemical changes in the gingival and odontogenic epithelia during the late stages of tooth eruption in the rat molar, using antibodies to cytokeratin 14(CK14), cytokeratin 18(CK18), EGF receptor, p75 NGFR receptor and PCNA.Conventional H-E staining and immunohistochemistry for CK14 showed that the dental lamina for rat molars is composed of an oblique part that connects to the oral epithelium and a horizontal part that directly connects to tooth germs. The oblique part of the dental lamina did not disrupt throughout the development of molar teeth, but regressed during the late eruption period. The regressing dental lamina contained a number of epithelial pearls and few apoptotic cells. The apical portion of every molar tooth germ was combined with horizontal dental lamina with a wide transitional zone, characterized by multiple layers of cuboidal epithelial cells.The immunohistochemistry by PCNA indicated that the cells in the epithelium of the transitional zone have a higher potential of mitosis than cells in the typical outer enamel epithelium. Disruption occurred in the epithelium of the transitional zone and in the connective tissue with blood vessels penetrating into the stellate reticulum of the enamel organs during the advanced eruption stages. Epithelial cells that proliferated from the epithelium of the transitional zone extended towards the stellate reticulum layer, and formed a reticular formation of reduced enamel epithelium by fusion with epithelial cords thet proliferated from stratum intermedium cells of the enamel free area.While the reticular reduced enamel epitheliunl showed a weak EGFR-like immunoreaction, a similar structure was negative to anti-NGFR. By the final stage of eruption, reduced enamel epithelium completely fused with oral epithelium at every cusp region, and keratinization progressed not only from the outer surface but also from the inner surface in the fused epithelium. Distribution of Markel cells was investigated using anti-CK18 as the contribution of these cells in the formation of eruption passage was suspected. However, no Merkel cell was detected during entire period of tooth eruption stage.

View full abstract

We studied 463 cardiovascular disease patients who were referred for evaluation and treatment of oral disease at Iwate Medical University Dental Hospita1 (IMUDH) by the Second Department of Medicine at Iwate Medical University and Iwate Medical University Memorial Heart Center from June, 1997 to December, 2000. As for cardiovascular disease, 2320f the patients (50.1%) had vascular disease, 199 patients (43.0%) hypertension, and 123 patients (26.4%) ischemic heart disease. The oral diseases of the subjects were as follows:188 patients (40.6%) had Inarginal periodontitis,106 patients (22.9%) apical periodontitis,82patients (17.7%) remaining root and 78 (16.8%) patients with dental caries. Regarding dental procedures at IMUDH,157 patients (33.9%) had their teeth extracted,120 patients (25.9%) had periodontal disease treated,106 patients (22.9%) were only evaluated and 102 patients (22.0%) were instructed in tooth brushing.243 patients (52.5%) had their dental treatment completed within 2 weeks.
An oral infection focus, such as marginal periodontitis, apical periodontitis and pericoronitis of wisdom teeth, can cause infective endocarditis or postoperative infection of cardiovascular disease.119patients (70.8%) out of 168 who were referred to us at the preoperative stage and had no oral complaint, had oral infection focus. Therefore, two thirds of the patients with cardiovascular disease in our institutions seemed to need dental procedures in order to irnprove cardiovascular treatment results.

View full abstract

Narrowed dental puIp cavities and obturated root canals produced by diffuse calcification and pulp stone are often observed in advanced periodontal disease. Possibly inflammatory cytokines following periodontitis may have served as the stimulus inducing the pulp calcification, but the details are not clear.
The purpose of this study was to investigate the relation between pulp calcification and the bone morphogenetic proteins (BMPs) expressed in the dental pulp cells of advanced periodontitis cultivated in vitro, and to analyze the effect of tumor necrosis factor-α (TNF-α) stirnulation on the expression of BMPs. The calcification process of the dental pulp cells was examined by alcian blue staining, von Kossa staining, immunostaining methods (BMP-2, BMP-4, osteonectin, osteocalcin and OB-cadherin) and mapping with combined microanalyzers. The mRNA expression of BMP-2, BMP-4 and transforming growth factor-β2 (TGF-β2) was investigated by reverse transcription-polymerase chain reaction (RT-PCR) methods. Dental pulp cells formed some nodules at 4 weeks of the cultivation in the medium without ascorbic acid and β-glycerophosphate. They included alcian blue-positive glucosaminoglycans, osteonectin, osteocalcin and TGF-β2. The cells in the periphery of nodules seemed to be differentiated odontoblastic cells. The nodules showed calcification at 8 weeks after cultivation by mapping with combined microanalyzers and von Kossa staining. The nodules were positive for BMP-2 and BMP-4 at 4 and 8 weeks after cultivation. BMP-4 expression increased with TNF-α stimulation, while BMP-2 expression decreased. The results suggest that TNF-α probably serves as a kind of stimulus in dental pulp calcification of teeth with periodontitis.

View full abstract

The thin HA layer that was deposited by anode oxidation and hydrothermal treatment (SA treatment) on a titanium surface, was called by a SA film.
It was suggested that the SA film was reported exhibiting bone conduction, long term stability and high adhesion strength with a titanium substrate by a study result in vivo and in vitro.
The purpose of this study was to examine the shape and crystal structure of HA in a SA film by SEM, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).
An anodic oxide film, SA film and comparison matter were measured by SEM, XRD, XPS.

From SEM and XRD, it was made clear that HA of a hexagonal system deposition on a SA film and three layers of SA film presented structure.
In the examination by XPS, the anodic oxide film moved to the low energy side and the SA film moved to the high energy side compared with HA of the comparison matter.
By XPS, it became clear that a SA film formed HA of higher crystallization than HA.

View full abstract

To simulate the temporomandibular loint articular cavity irrigation, a superior articular cavity model was fabricated with ethylene-vinyl resins, based on measurements by single-contrast arthrography and the scale of the mantle tube. Experiment methods, after injection of lindigo carmine solution, the model was perfused with distilled water by the arthrocentesis (AC) and pumping lavage system(PLS)irrigation. Using particle induced X-ray emission, we quantitatively analyzed the amount of sulfur, a component element of the indigo carmine, contained in the effluent fluid and in the remaining fluid in the model. The differences in the effectiveness of the two irrigation methods were hydro-mechanically evaluated. AC was highly effective in cases in which an inflow needle was placed in the posterior compartment, an outflow needle in the anterior compartment, and the flow of the perfusate was fast;however, differences were observed depending on the position in which the outflow needle was inserted, PLS was considered to be a comparatively effective method.

View full abstract

Pathological examinations undertaken in our department in 2000 were statistically reviewed.
The number of biopsy materials amounted to a total of 631 from 531 cases(255 males,276 females).Cases in the seventh decade(122 cases)were found to be the most frequently.
In histological classifications of the exarninations, there were 160dontogenic benign tumors and tumor-like Iesions. The non-odontogenic benign tumors and turnor-like lesions consisted of 32 fibrous hyperplasias,16 hyperkeratoses(leukoplakias),14 hemangiomas,8 papillomas,7 pleomorphic adenomas, 6 irritation fibromas, 6 epithelial dysplasias, 5 1ipomas, 2 1ymphangiomas. Also found were 60 cases of non-odontogenic malignant which consisted of 53 squamous cell carcinomas,3verrucous carcinomas. The odontogenic cysts included 38 radicular cysts,10 prirnordial cysts,10 dentigerous cysts and 2 calcifying odontogenic cysts. The non-odontogenic cysts included 40 mucous retention cysts(mucocele),20 postoperative maxillary cysts, and 3 incisive canal cysts.
In addition,141ichen planuses,14 Sjogren’s syndromes,13 chronic and localized hyperplastic gingivitis(epulis)were found.

View full abstract

There are some reports described about fusion of permanent incisors to supernumerary teeth, but there are few reports about multi-rooted incisors and their treatment cases. We report the treatment of an upper central incisor with two roots in this paper. The chief complaint of the patient was redness and swelling at the buccal gingiva of the upper right incisor.The right central incisor had one crown and two roots fused mesiodistally. Surgical procedure including amputation of the distal root, and filling the bone defect with hydroxyapatite granules was performed after initial treatment. Then, gingival symptoms disappeared and the tooth was preserved without gingival recession of the treated area. It is thought that the treatment of multi-rooted incisors needs to be performed in the same way as the treatment of the multi-rooted molars with furcation involvement.

View full abstract

Malocclusions such as anterior and/or posterior crossbite are often caused by the abnormal growth of the maxilla following the surgery of unilateral cleft lip and palate patient. In these patients, we have successfully treated in four stages from infancy to adulthood. The first stage is preoperative maxillary orthopedic treatment for newborns before cheiloplasty, and the observation of their maxillary growth and occlusion. The second stage begins with maxillary expansion and/or protraction. The third stage is the alignment of the permanent teeth using a Inultibracket system. The last stage includes retention, prosthodontic treatment and long・term observation.
In this study, we observed a case of severe class Ⅲ malocclusion and evaluated the effect of orthodontic treatment, from the second stage to the forth stage over a period of 19 years. At the first medical examination, the patient was a girl, 12 years 11 months old, with a complete left cleft lip and palate, and had a concave facial profile and a severe Class Ⅲ malocclusion. Total active treatment time was 5 years and 7 months. Although we could not obtain a skeletal improvement by orthodontic treatment, anterior cross bite was improved mainly due to the anterior tooth movement. The skeletal change, from 19 to 32 years old, was almost unnoticeable, while slight changes were visible and observation is necessary to check the stability of the resulting occlusion.

View full abstract