The Journal of Nihon University School of Dentistry最新文献

Volumetric dye penetration into the canals of 131 teeth was studied spectrophotometrically. The teeth were first divided into three groups according to the degree of curvature. Each group was then subdivided into four groups, in which the Thermafil and lateral condensation techniques were used with or without ultrasonic irrigation. Significant microleakage differences were observed between group I (0-10 degrees) and group III (21-30 degrees) for lateral condensation filling with ultrasound irrigation and Thermafil filling without ultrasound irrigation (p < 0.05).

A retrospective study of lateral cephalograms of 24 Japanese adults with Class III malocclusion was made in order to compare the angles of the horizontal plane between open bite and non-open bite cases. The following results were obtained: i) There was no significant difference in the angle of the NF-upper occlusal plane between the open bite and non-open bite groups. ii) There were significant differences between the two groups in the angle of the SN-upper and lower occlusal planes, the FH-upper and lower occlusal planes and MP-lower occlusal plane. There was also a significant difference between the groups in the distance from the Xi point to the upper occlusal plane. iii) In both the open bite and non-open bite groups there was a wide variation in occlusal plane angles, compared with normal cases.

A study was conducted to analyze the effects of propolis mouth rinse on the repair of surgical wounds after sulcoplasty by the modified Kazanjian technique. Twenty-seven patients who underwent sulcoplasty were divided into three groups: C1--patients who did not use the mouth rinse C2--patients who used a mouth rinse containing 5% aqueous alcohol T--patients who used a mouth rinse containing 5% propolis in aqueous alcohol solution. The patients returned 7, 14, 30, and 45 days after surgery for cytological and clinical evaluation. It was concluded that: 1) the mouth rinse containing propolis in aqueous alcohol solution aids repair of intra-buccal surgical wounds and exerts a small pain-killing and anti-inflammatory effect; 2) the vehicle employed has a minor irritant effect on intra-buccal surgical wounds; 3) exfoliative cytology allows epithelization of intrabuccal surgical wounds.

Hypomineralized area (HMA) scores were determined for hamster molars during tooth maturation and fluoride treatment. It was found that the molars were maturing until the animals were 45 days old, but from 45 to 74 days of age the HMA scores remained constant. Fluoride treatment decreased the HMA score. The group with the lowest HMA score was fed a cariogenic diet, inoculated with Streptococcus mutans and received topical fluoride treatment.

Thorough X-ray examination is a valuable adjunct in the clinical assessment of supernumerary teeth. Three cases of supernumerary teeth comprising paramolars and molars are presented with radiographic documentation. All the patients received surgical treatment after full clinical and radiographic evaluation.

A study was undertaken to investigate bone regeneration in guinea pig mandibles implanted with Pyrost in comparison with artificial bone defects as controls. Bone defects were prepared in the angles of mandibles of 30 guinea pigs. The findings demonstrated that this bone substitute material stimulated bone healing, i.e. bone regeneration, in comparison with empty control cavities. Bone regeneration and new bone formation were found to be more extensive in Pyrost-implanted areas than in controls.

A study was conducted to examine the effect of endotoxin present in periodontal pockets on the proliferation and attachment of human cell lines on the culture plates (Ca9-22 and gingival fibroblasts). The endotoxin was collected from periodontal pockets of anterior teeth in patients with periodontal disease by subgingival irrigation with sterilized distilled water. The solutions obtained were then subjected to hot phenol-water extraction. The collected endotoxin from periodontal pocket and four other kinds of endotoxin obtained commercially as positive controls were added to cell cultures and the numbers of viable cells on the culture plates were counted. Among the commercially available endotoxins used in this study, only 500 micrograms/ml of endotoxin derived from Escherichia coli 0111:B4 significantly decreased the number of attachment cells of Ca9-22 and gingival fibroblasts on the culture plates. Endotoxin from periodontal pockets at 5 micrograms/ml also significantly decreased the numbers of attachment cells of both cell lines.

To examine the disinfectant effects on oral microbes of an alginate impression material supplemented with 1% chlorhexidine as the aseptic ingredient (Coe Hydrophilic Gel, CHG), several cell suspensions of oral microbes (3 Gram-positives, 2 Gram-negatives and 1 yeast) were exposed to the surface of cast CHG or that of a control impression material for 5 or 30 min. They were then transferred to the surfaces of agar plates. Colony formation was estimated after culture for several incubation periods. No growth of bacteria on the plates was observed when the suspensions had been exposed to CHG even for 5 min, whereas for the control material, all the bacteria formed colonies. The yeast showed colony formation irrespective of the kind of impression material and the duration of exposure. Thus, it appears that use of an impression material supplemented with 1% chlorhexidine such as CHG may protect clinical staff and dental technicians from possible bacterial infections associated with the impression procedures.

Aqueous solutions of methacryloyl tyrosine amide (MTYA), glyceryl methacrylate (GM), glutaraldehyde and succinic acid were prepared and their effectiveness as pretreatment reagents was evaluated by measuring the tensile bond strengths between resin composite and polished enamel. Pretreatment of polished enamel with MTYA.GM.S3 (A: 6% MTYA + 70% GM aqueous solution, B: 3% succinic acid aqueous solution) gave bond strengths of about 7 MPa, whereas pretreatment with MTYA.G.GM.S3 (A: 6% MTYA + 70% GM aqueous solution, B: 3% succinic acid + 2% glutaraldehyde aqueous solution) gave values of about 5 MPa. The mean bond strengths of each after 60 s of scrubbing with MTYA.GM.S3 or by MTYA.G.GM.S3 were raised to about 9.5 MPa, and the type of bond failure was fracture of the bonding agent. Although there were no resin tags, it was found that resin composite was able to adhere to polished enamel without acid etching.