Dentistry in Japan最新文献

Normal anatomy of the maxillofacial regions is clearly shown by both CT and MRI. The use of dental devices causes deterioration in CT and MRI of the tongue and oral floor. A high-resolution bone window display is highly useful in examining bony structures. Contrast CT is useful in diagnosis of tumorous, inflammatory, and vascular lesions. MRI shows the extensions of tumors more clearly than CT, and MRI enhanced with Gd-DTPA is very useful in determining tumor extensions into bony structures. Both CT and MRI should be used in diagnosis of maxillofacial lesions.

Differences in pockets depth reduction rates were compared between different tooth types and sites after initial treatment in 41 adult periodontitis patients whose O'Leary plaque records were maintained at less than 10% during initial treatment. Pocket depths were significantly reduced after initial treatment. Response to treatment was good at 15, 25, 14, 24, 33, 43, 31, 41, 34 and 44; but was poor in 11, 21, 17, 27, 37 and 47. Response to treatment was poor on the mesiopalatal surfaces; midpalatal surfaces of 16 and 26; the distolingual surfaces of 17, 27, 37 and 47; and the mesiopalatal surfaces of 11 and 21; but was good on the distobuccal and midpalatal surfaces of 14 and 24, the mesio- and distal-buccal surfaces of 15 and 25; and the mesiolingual surfaces of 34 and 44. The tooth types and root surfaces that require careful attention during treatment were clarified.

Carbonic anhydrase (CA) from pilocarpine-treated (1.5 mg/kg body weight; i.p.) rat saliva was purified by inhibitor affinity chromatography. The purified CA contained Mr 42000 and 39000 proteins on sodium dodecyl sulfate polyacrylamide gel electrophoresis. In addition to the erythrocyte isozyme (Mr 30000), salivary gland CA from rats without pilocarpine stimulation contained Mr 39000 and 33000 proteins and that from rats with pilocarpine stimulation also contained Mr 42000 protein. The 42000Da and 39000Da proteins bound to concanavalin A and were cleaved by endo-beta-N-acetylglucosaminidase F to become 39000Da and 33000Da proteins. These results suggest that, under the influence of pilocarpine, salivary gland cells synthesize a new glycoprotein, Mr 42000, via N-linked glycosylation of a 39000Da glycoprotein, which is the only secretory glycoprotein in the unstimulated salivary gland and is produced by N-linked glycosylation of a 33000Da polypeptide.

A new electronic root canal measuring device called "ENDEX" which is able to determine the root canal length under moistened conditions using a relative value of different alternative electric currents is discussed in this study. This study is designed to investigate the efficiencies of the new device, in vitro, with respect to change in the root canal environment; namely the influence of the size of K-file, the diameter of the apical foramen and the various root canal irrigants. According to the present study, it was confirmed that the location of the apical foramen was clearly detected under moistened root canal with saline solution using any size of K-file. The locations of the tip of K-files were 0.5 mm inside the apical foramen when the relative value displayed 0.3 Volt, so that the apical constriction could not disturb during root canal measurement. One of the big problem with prior electrical measurement devices was not being able to determine the canal length under moistened conditions. However with this improved device, intracanal irrigants, such as saline, 5% NaOC1, 14% EDTA and 3% H2O2 did not interfere in detecting apical foramen irregardless of the size of K-file and the size of the apical foramen.

Work analysis by means of dental practice administration is necessary for every clinical dentist. Generally speaking, endodontics sometimes may ignore the study of the operator's difficulties and/or the patient's time burden. Two dentists had treated 72 teeth on 49 patients with single visits in endodontics in one month. Vital and infected canal treatment needed almost the same working time in our clinical system. Difficult cases and work factors affect working time longer and make the standard deviation larger. Difficulties had caused incisor work to consume more time than premolar treatments. In the case of molars, clinical experience helped treatment on maxilla to be quicker than on mandible. Knack factors were to be revealed in this qualitative study.

Outer membrane proteins (OMPs) were extracted from whole cells of several Porphyromonas and Prevotella strains and their OMPs profiles were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The SDS-PAGE analysis revealed that OMP profiles of Porphyromonas and Prevotella strains show species-specific patterns and P. gingivalis characteristically had two kinds of major outer membrane proteins (MOMPs). A 53 Kd MOMP from P. gingivalis FDC 381 and a 67 Kd MOMP from ATCC 33277 were purified. Sera from periodontitis patients and healthy subjects were analyzed for immunoreactivities against both the purified MOMPs of P. gingivalis by immunoblotting analysis. The sera from 18 patients reacted to the 53 Kd MOMP, 10 to the 67 Kd MOMP, and only three sera reacted to both MOMPs. The sera of healthy subjects also reacted, but weakly, to either the 53 Kd or 67 Kd MOMP. The SDS-PAGE OMP profiles prepared from 13 clinical isolates of P. gingivalis and immunoblotting analysis of human sera against the two kinds of P. gingivalis MOMPs indicate that periodontal diseases resulting from P. gingivalis are initiated and sustained by at least two MOMPs of P. gingivalis.

A new bone resorption model was developed by using living bone substrates and devitalized bones for isolated osteoclasts to act on. The extent of bone resorption was assessed by measuring the area and depth of resorption pits. The area and depth of pits made on living bones were greater than those of pits made on devitalized bone substrates. TIMP (100 micrograms/ml) reduced resorption on living bone in area and depth to the same amount of resorption on devitalized bone. E-64 (60 microM) significantly inhibited the resorption of devitalized bones. TGF-alpha (100 ng/ml) did not have significant effect on the resorption of any substrate. Indomethacin (100 ng/ml) reduced resorption on living bone to the same level of that on devitalized bone. These results suggest that resorption on living bone is aided by osteocyte-synthesis of metalloproteinases, among them collagenase, to degrade bone collagen through prostaglandin synthesis by viable cells in the substrates. The stimulation of bone resorption by TGF-alpha observed in organ culture appears not to be mediated by direct stimulation of osteoclast activity.

The percentage of potential TMJ dysfunction is high in orthodontic patients. The prevalence of TMJ dysfunction during orthodontic treatment and the correlation between TMJ dysfunction occurrence and orthodontic appliances were studied. One hundred and twenty-five male and 183 female orthodontic patients between 7.2 and 38.3 years of age with a mean age of 13.1 years without TMJ dysfunction at first examination were examined for clinical symptoms. TMJ dysfunction was found in 26 patients (8.6%). The frequency of occurrence of TMJ dysfunction in patients treated with a chin cap appliance was 10.9% (14/129) and 6.7% (7/105) for those treated with a multibracket appliance. Chin cap appliance treatment was begun after the pubertal growth peak in eight patients, during the peak in three patients, and before the peak in three patients. Clinical symptoms continued in four patients who continued to use the appliance under the same conditions, and nine patients who were treated with proper countermeasures became free from clinical symptoms.

The effects of phenolic dental medicaments on lipoxygenase activities of rat dental pulp and human platelets were studied. The major product derived from [14C] arachidonic acid by the homogenate of rat dental pulp was 12-HETE (15-HETE). Eugenol and p-chlorophenol dose-dependently inhibited HETEs formation. The IC50 values of eugenol and p-chlorophenol were 0.62 and 0.34 mM respectively. The concentrations of these compounds that inhibit lipoxygenase were similar to those required to inhibit cyclooxygenase. These compounds also inhibited 12-lipoxygenase of human platelets with a similar range of concentrations. The results show that phenolic dental medicaments inhibit pulpal and platelet lipoxygenase. Thus, inhibition of arachidonic acid metabolism by phenolic dental medicaments via the lipoxygenase pathway may be involved in the analgesic and anti-inflammatory effects of the medicaments in endodontic therapy.