Accurate diagnosis and exact treatment planning are very important for successful implant treatment. Pretreatment examination and simulations using CT can be especially effective information sources, and diagnosis by CT imaging before treatment substantially enhances the security and safety of the treatment plan. New interactive CT software (SIM/Plant^TM) which enables diagnosis of bone morphology and quality, and also implant simulation on a personal computer through multiplanar reformation of CT images, has been developed. Stereolithography-models (SLMs) are reproduced anatomical morphological models of an individual patient's bone structure from the information obtained by the CT scan, and is fabricated out of light cure resin. In this article, SLMs and SIM/Plant^TM for simulation of various examinations and diagnosis incorporating CT information are described, and their features are introduced. (J. Oral Sci. 41, 157-161, 1999)
Proper examinations before treatment are needed in any implant case regardless of the degree of difficulty. It is particularly important in difficult cases to collect as much accurate information as possible. Pretreatment examinations and simulation using CT can be very important information sources. It was emphasized that prosthodontic factors including occlusion maintenance are important for the long-term success of implants. Restorations should not be made where an implant was placed, but implants should be placed at the optimize position for the restorations. CT information is indispensable in this regard.

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Cytokines play an important role in the pathology associated with chronic inflammatory diseases. One of these cytokines, interleukin 6 (IL-6) is a major mediator of the host response to tissue injury, infection and bone resorption. In the present study, gingival crevicular fluid (GCF) level of IL-6 was determined in patients with non-insulin dependent diabetes mellitus (NIDDM) with periodontitis, adult periodontitis, and healthy controls by use of an enzyme linked immunosorbent assay (ELISA). Twenty-four NIDDM patients with periodontitis, twenty-four adult periodontitis and twenty-four healthy controls were selected for the study. GCF sampling was performed on the vestibular aspects of maxillary incisors and canine teeth. Plaque index (PI), gingival index (GI), gingival bleeding time index (GBTI), probing depth (PD) and probing attachment levels (PAL) were recorded from each sampling area and also the entire dentition. NIDDM and adult periodontitis patients had numerous sites with radiographic evidence of alveolar bone resorption, loss of attachment and pocket depth greater than 3 mm. The mean GCF IL-6 level was 2.43 ± 0.97 ng/ml in NIDDM patients, 1.31 ± 0.92 ng/ml in adult periodontitis and 0.62±0.58ng/ml in healthy subjects, respectively (p < 0.05). GCF IL-6 levels were markedly higher in NIDDM and adult periodontitis groups compared to the healthy controls. No correlation was found between GCF IL-6 levels and all clinical parameters. These findings suggested that GCF IL-6 levels were significantly higher in the area of inflammation and periodontal destruction locally. The high IL-6 levels in NIDDM patients might be due to different microbial flora in periodontal pockets and altered immune system. Future studies are needed to evaluate the complex interaction among IL-6 GCF levels, host response and local microbial environment in the NIDDM patients. (J. Oral Sci. 41, 163-167, 1999)

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It is thought that salivary proteins on bacterial cells have some influence on the adhesion of oral bacteria onto the surface of oral tissues and on bacterial aggregation. Initially, this study sought to examine the phenomenon of salivary protein adsorption to the surface of Streptococcus mitis ATCC 903 using ³H-labeled salivary proteins. We investigated the effects of hydrophobic level and lectin-ligand binding on adsorption of salivary proteins, and also the influence of cell surface components on adsorption. The results showed that the adsorption of salivary proteins was clearly reduced by the presence of Tween 20, LiC1, NaSCN, Hexadecane and some sugars. The adsorption was also affected by the pH level, and protease treatment or heat treatment of cells also decreased the volume of adsorbed proteins. Although the adsorption of proteins onto heat-treated cells was dramatically reduced by the presence of LiC1 and NaSCN, the presence of sugars had little influence on this adsorption. These findings suggest that the main adsorption of salivary proteins is due to hydrophobic factors, and the heat-sensitive surface components of the cells had some relation to lectin-ligand binding. Therefore, it appears important to study the adsorption of salivary proteins onto cells since the salivary proteins on bacterial cells play an important role in their adherence to the saliva-coated oral tissues and bacterial aggregation. (J. Oral Sci. 41, 169-172, 1999)

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A 14-year retrospective study was performed on 47 odontomas from the files of the 1st Department of Oral and Maxillofacial Surgery at Nihon University School of Dentistry. Fifty-seven percent of the patients were male and 42.6 % were female. The age distribution was 8 to 48 years with a mean age of 22 ± 9.0 years. There were no particular symptoms associated with the odontomas, and 63.8 % of our patients had no symptoms. However, 12 patients complained of swelling and 9 of pain. The tumor was found in the maxilla in 42.6 % and in the mandible in 57.4 %. According to the WHO histological type classification, 53.2 % of the tumors were classified as compound odontoma and 46.8 % as complex odontoma. The size of the tumor ranged from 5 mm to 42 mm in diameter. The average complex odontoma was much bigger than the average compound odontoma. Ghost cells were found 11 cases in our series. In addition, odontogenic epithelium was found in 16 cases. Twenty seven patients had impacted teeth in association with odontoma and 24 of the 27 teeth were removed at the time of surgical enucleation of the tumor, while 3 cases were treated by orthodontically assisted eruption. There was no recurrence in any of the studied cases. (J. Oral Sci., 41, 173-176, 1999)

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This study aimed to investigate and compare the lipid and polysaccharide content of the cemental surfaces of healthy and periodontally-involved teeth. Thirty periodontally-involved single-rooted teeth from fifteen patients with localized juvenile, adult and rapidly progressive periodontitis were included in the experimental group and 5 healthy teeth were assessed in the control group. Frozen serial sections were obtained and stained with hematoxylin-eosin for morphological assessment. Oil-Red-O and Alcian Blue-Periodic Acid Schiff stains were used to evaluate the presence of lipids, neutral and acidic polysaccharides using light microscopy. It was found that with hematoxylin-eosin staining in the experimental group, both the involved and uninvolved cementum surfaces of teeth, which belong to all periodontitis groups, showed generally irregular surfaces that contain some resorption areas. Alcian Blue-Periodic Acid Schiff positive staining was observed only superficially and at the areas associated with microbial dental plaque. However, Oil-Red-O staining was positive only superficially at 5 teeth that belonged to localized juvenile and rapidly progressive periodontitis groups. Apparent lipopolysaccharide staining into cementum was not seen in any of the diseased teeth. The results presented here suggest that endotoxin was only localized in superficial layers and associated with only microbial colonization. (J. Oral Sci., 41, 177-180, 1999)

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We carried out a clinical evaluation of the hard tissue fill following treatment of ligature-induced peri-implantitis in dogs. Four dogs were used and their mandibular premolars (P2, P3 and P4) were removed. After 3 months of healing, two titanium implants were placed on each side of the mandible. After 3 months, the abutment connection was performed, and experimental peri-implantitis was induced by placement of cotton ligatures in a submarginal position. The ligatures and abutments were removed after one month, and the peri-implant bone defects were assigned randomly to one of the treatments : debridement (control), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG), and debridement plus guided bone regeneration associated with a mineralized bone graft (GBR+BG). Clinical measurements of the peri-implant bone defects before and 5 months after treatment revealed no statistically significant differences between the defects treated by GBR, BG and GBR+BG. These 3 treatment methods provided more hard tissue fill than debridement alone (p < 0.05). Thus, it can be concluded that GBR, BG or a combination of the two techniques can enhance the hard tissue fill in defects caused by peri-implantitis in dogs. (J. Oral Sci., 41, 181-185, 1999)

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Pus samples of 30 patients with closed dentoalveolar abscesses who had not received antimicrobial therapy for at last two months were screened for the presence of β-lactamase-producing anaerobic bacteria. From these 30 pus samples, a total of 112 bacterial strains were isolated; 83 of them were strict anaerobes and 29 were aerobes. β-lactamases activity of the selected anaerobic bacteria was tested after identification of the isolates and was detected in 5 of the total 83 (6 %) strict anaerobic isolates, whereas these 5 strains were isolated in 4 of the 30 (13.3 %) pus samples. The species with β-lactamase activity were in the Prevotella intermedia (4 from 14 isolates) and the Fusobacterium nucleatum (1 from 9 isolates) groups. None of the gram-positive and the other gram-negative anaerobic strains were β-lactamase positive. (J. Oral Sci., 41, 187-190, 1999)

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In recent years, ultrasonic waves have been an interesting subject for studies due to their wide range of applications in medical diagnoses. In this study, the acoustic properties of the structure of human teeth was determined with the ultrasonic imaging technique. This study may offer some fundamental findings related to the clinical application of the ultrasonic imaging technique in the further development of a virtual system for dental education and research. Twenty freshly-extracted permanent human teeth (10 molars and 10 premolars) were used to investigate their acoustic velocity and impedance by the ultrasonic image analyzing system with a high-resolution focusing probe. Additionally, the relationship between the acoustic properties and the hardness of the teeth was evaluated. It was found that the acoustic properties of the human teeth were influenced by factors related to their structure, such as degree of calcification, distribution of dentinal tubules, and volume of the dentin matrix. The acoustic velocity and impedance showed an apparent correspondence to the hardness of tooth. This analyzing system provides visual information related to tooth structure that can easily quantitatively evaluate their acoustic properties. It is expected that this system will have a wide range of applications and be further developed for clinical uses. (J. Oral Sci., 41, 191-197, 1999)

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Five cases of supernumerary teeth with eumorphism in the lower incisor region of the permanent dentition are reported. The patients were two males and three females. One (a 31-year-old woman) of them had bilateral supernumerary teeth. The review of the English language literature yielded only one such bilateral supernumerary teeth in the lower incisor region of the permanent dentition was reported. (J. Oral Sci. 41, 199-202, 1999)

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