Gifu Shika Gakkai zasshi = The Journal of Gifu Dental Society最新文献

Fifty infected root canals were examined whether they had been in aseptic condition or not after endodontic treatment. PLADIA was used for the examination of bacteriologic culture. Twenty eight cases were positive, 22 cases were negative, and the percentage of positive was 56%. Of the anterior teeth, 13 cases were positive in 23 cases (57%), In the posterior teeth, 15 cases were positive in 27 cases (56%), 5 cases were positive in 17 cases (29%) with clinical symptoms before treatment, 23 cases were positive in 33 cases (70%) without clinical symptoms before treatment. These results showed that the treated root canals which had been well adapted to root canal filling by clinical symptoms had a high percentage of positive of bacteriological culture.

Studying of influence of periodontal disease on vitality of pulp, the response thresholds of 421 teeth (250 normal teeth, 171 periodontal diseased teeth) were examined electronically by means of an automatic pulptester. (ANALYTIC TECHNOLOGY CO.) The pulp tester values of three experiments were averaged. The average value of normal teeth was 36.3 and that of periodontal diseased teeth 31.4. The response thresholds of periodontal diseased teeth were lower than those of normal teeth. This indicated that pulp was inflamed by periodontal disease and pulp vitality became weak.

The effects of thickness and background color on the color of five commercial light-cured composite resins were studied by a dental color meter using the CIE 1976 L*a*b* color system. As thickness increased from 1.0 to 4.0 mm, values of L*a*b* decreased for white and dentin color background but showed no obvious difference in color for a black background. the color of composite resins were not in fluenced by background color in a thickness of 4.0 mm. The values of color difference for 1.0 and 2.0 mm thick samples have a larger value than the same 4.0 mm samples. The color difference was recognized even for the same shade name in five representative kinds of composite resins.

Intramembranous localization of alkaline phosphatase (orthophosphoric monoester phosphohydrolase, alkaline optimum, EC 3, 1, 3, 1; AlPase) was observed biochemically in Bacillus megaterium KM grown in 1% polypeptone medium containing 0.5% NaCl at 37 degrees C under aerobic conditions and harvested at the latter logarithmic phase. AlPases from B. megaterium have been separated into soluble and membrane-bound forms by the centrifugation after cell disruption by sonication. The membrane-bound enzyme was further fractionated to two forms by phase separation using a non-ionic detergent, Triton X-114; one was successfully solubilized into the aqueous phase and the other remained in the Triton phase. Both AlPases of sonication- and Triton-solubilized forms were partially purified by gel filtration and anion-exchange column chromatographies. Their molecular weights were different (52,000 for soluble and 66,000 for Triton-solubilized forms) and the Vmax of the sonication-solubilized enzyme (227 nmol/min/mg protein) was 11-fold higher than that of the Triton-solubilized one although similar Km values (1.7 and 2.3 mM) were observed. Optimum pH of these enzymes tended to shift to a neutral range during the purification steps. These results suggest the multiplicity of AlPase anchoring to the membranes; 1) sonication-solubilized form which may be buried within the membrane lipids by its hydrophobic peptide and solubilized by the cell disruption, 2) detergent-solubilized form which may be bound loosely to the membrane by its hydrophobic domain and solubilized due to the amphiphilicity of enzyme protein, and 3) insolubilized form which may be bound fast to the membrane by its strong hydrophobicity and also have the function of enzymatic ability.

This time, we used palatal plates with the individual palatal rugae using the plastic plate for copying the individual palatal rugae easily, and studied the influence of the pronunciation concerning the changes of the Formant frequencies with Sound Spectrograph.

A 12-year-old boy was first seen with the chief complaint of reverse occlusion. His records allowed a class III malocclusion, crown fracture of 1 angle and -1.1 degrees angle SN to FH. Therefore, we corrected angle SN to FH from -1.1 degrees to 7 degrees and treated him with intermaxillary anchorage appliance and by the edgewise method.

We use some palatal plates with some Kinds of palatal rugae; ready made, patterned, individually copied and omitted, and studied the influence of the pronunciation acoustically concerning the Formant Frequency.

This study was designed to test the abrasion resistance of microwave-curing denture base resin. We also studies the effects of surface smoothing treatment on abrasion resistance. Test resin was allowed to polymerize, and then buff polished or treated by surface smoothing. Knoop hardness was measured both prior to and following surface treatment. Then, the test material was subjected to brushing using a newly developed toothbrushing machine. Volume and surface roughness of the material were measured before and after brushing, and the surface structure of the material was examined with SEM. Microwave-curing denture base resin is equal in Knoop hardness and abrasion resistance to its conventional heat-curing counterpart, although it is smoother at the surface. The resin improved both in hardness and abrasion resistance when it underwent surface smoothing treatment regardless of whether it was heat-cured or microwave-cured. As was evident from SEM observations that both types of resins suffered superficial chipping following severe brushing, which is in accordance with our previous clinical findings.

A new dental cement was developed by use of tetracalcium phosphate monoxide (Te-CP) and dicalcium phosphate dihydrate (DCPD). When an equimolar mixture of the two calcium phosphates was mixed with diluted phosphoric acid, it hardened into a phase of hydroxyapatite (HAp) resembling the main inorganic phase of hard tissues. The present study was undertaken to investigate physico-chemical properties of this newly developed apatite cement and to evaluate its potential as dental cement to clinical application. The setting time was reduced in the presence of synthetic HAp, indicating added HAp to be an accelerator in the setting reaction. The pH of paste rapidly increased to a neutral range from initial solution acidity of about 2.0 and the subsequent setting reaction proceeded in a neutral and weak alkaline pH range. The hardened solid 4 hours after saturation was identified as single phase of apatite by X-ray diffraction. The HAp crystallinity of the set cement varied with the crystallinity of HAp added as setting accelerator. The wet compressive strength of the cement stored for one day in synthetic saliva at 37 degrees C increased to 400 kg/cm2 as added HAp crystallinity decreased. Moreover no disintegration took place when the cement was stored at 37 degrees C in synthetic saliva, which was undersaturated with respect to DCPD but well supersaturated for HAp. In clinical application to animals, no significant cleavage was observed between the hard tissues and the cement by SEM even three months after the cement paste was filled in the tooth cavity of monkeys. In the specimen prepared one week after implantation in the medullary canal of rats, no inflammatory cell appeared. The specimen prepared one month after implantation showed that the set cement was tightly contacted with newly formed bone. These findings strongly suggest that the newly developed self-setting apatite cement is useful as a pulp capping agents, root canal fillings and bone substitute.

The patient, a 10-years and 7-month-old boy, demonstrated maxillary protrusion (a pseudo class I malocclusion) complicated by horizontal open bite, space defect of 5 5, and represented that point A was +3.0 mm, pogonion was -8.0 mm to McNamara line respectively. His 4 first premolars were extracted and he was treated with an edgewise appliance together with a high pull head gear, palatal bar, class III elastics, class II elastics and up-down elastics for 3 years. A functional occlusion and good profile was obtained with good growth, chin control and tooth movement.