Biomedical subjects

Masaomi Ikeda

Publications and source records attributed to Masaomi Ikeda.

11 recordsLinked to original sources

PubMed2006

Effect of simulated pulpal pressure on all-in-one adhesive bond strengths to dentine.

OBJECTIVES: To evaluate the durability of all-in-one adhesive systems bonded to dentine with and without simulated hydrostatic pulpal pressure (PP). METHODS: Flat dentine surfaces of extracted human molars were prepared. Two all-in-one adhesive systems, One-Up Bond F (OBF) (Tokuyama Corp., Tokyo, Japan), and Fluoro Bond Shake One (FBS) (Shofu Co., Kyoto, Japan) were applied to the dentine surfaces under either a PP of 0 or 15cm H(2)O. Then, resin composite build-ups were made. The specimens bonded under pressure were stored in 37 degrees C water for 24h, 1 and 3 months under 15cm H(2)O PP. Specimens not bonded under pressure were stored under zero PP. After storage, the specimens were sectioned into slabs that were trimmed to hourglass shapes and subjected to micro-tensile bond testing (muTBS). The data were analysed using two-way ANOVA and Holm-Sidak HSD multiple comparison tests (alpha=0.05). RESULTS: The muTBS of OBF fell significantly (p<0.05) when PP was applied during bonding and storage, regardless of storage time. In contrast, although the muTBS of OBF specimens bonded and stored without hydrostatic pressure storage fell significantly over the 3 months period, the decrease was less than half as much as specimens stored under PP. In FBS bonded specimens, although there was no significant difference between the muTBS with and without hydrostatic pulpal pressure at 24h, by 1 and 3 months of storage under PP, significant reductions were seen compared with the control group without PP. CONCLUSION: The muTBS of OBF bonded specimens was lowered more by simulated PP than by storage time; specimens bonded with FBS were not sensitive to storage time in the absence of PP, but showed lower bond strengths at 1 and 3 months in the presence of PP.

Composite Resins↗

PubMed2006

Quantitative assessment for stimulated saliva flow rate and buffering capacity in relation to different ages.

OBJECTIVES: To evaluate salivary flow rate and buffering capacity using a quantitative pH measurement among three broad age groups. METHODS: The population consisting of 117 patients was classified into three age groups: young, middle-aged, and elderly group. The volume of stimulated saliva after chewing gum was measured. Saliva samples were titrated with 0.1N HCl to evaluate the buffering capacity. Saliva pH change was measured directly using a hand-held pH meter. At the point of 50 microL of titrated HCl, individual salivary buffering capacities were ranked into one of the following three categories; high buffering capacity (above pH 5.5), medium buffering capacity (from pH 5.5 to 4.5), and low buffering capacity (below pH 4.5). RESULTS: Chi(2)-test showed that the proportional distribution of individuals in the three buffering capacity groups was not statistically different among the age groups (p>0.05). One-way ANOVA and Tukey's HSD test showed the flow rate of stimulated whole saliva in the young group was significantly greater than that of the middle-aged and elderly groups (p<0.05). Two-way ANOVA showed there was no significant interaction between the independent variables buffering capacity and age group (F=0.419, p=0.7950). One-way ANOVA and Tukey's HSD test indicated the flow rate showed significant differences among the three age and buffering capacity groups. CONCLUSIONS: Although a limited number of subjects were investigated in this study, the quantitative saliva assessment is useful as a screening method for different ages to identify patients with a low saliva flow rate and/or buffering capacity.

Adult↗

PubMed2006

Effect of curing method and storage condition on fluoride ion release from a fluoride-releasing resin cement.

The purpose of this study was to evaluate fluoride ion release from a resin-modified glass ionomer cement (Fuji IILC improved, FLC) and a fluoridated resin cement (Panavia F, PF) following different curing methods and storage conditions. The specimens, which were either light-cured (LC) or chemical-cured (CC), were stored in either distilled water (DW) or demineralizing solution (DS; pH 4.5) for 1, 3, 7, 15, 30, 60, and 90 days. Fluoride ion release was measured using a fluoride ion-specific electrode. Data (n = 5) were statistically analyzed using one- and three-way ANOVA (p = 0.05). A "burst effect" was observed in the first week from both materials. However, fluoride ion release from FLC was seven times higher than that from PF. Storage in demineralizing solution accelerated the amount of fluoride release from both materials. In addition, LC yielded a lower amount of fluoride ion release from both materials, as compared to CC. It was concluded that both curing mode and storage medium influenced the amount of fluoride release from the tested materials.

Analysis of Variance↗

PubMed2006

Coronal leakage inhibition in endodontically treated teeth using resin-coating technique.

The purpose of this study was to evaluate coronal leakage inhibition using a resin-coating technique after endodontic treatment. Thirty-six human incisors were cut at the cementoenamel junction, and endodontic obturations were performed. The specimens were randomly divided into three groups according to post space preparation (10 mm depth), resin coating, and temporization. For the resin coating, the dentin surface was coated with either a combination of Clearfil SE Bond and Protect Liner F (SE/PLF) or RZII (RZ). Then, the specimens were stored in 37 degrees C distilled water for 24 hours and placed in 1% methylene blue solution for 48 hours. After which, the specimens were sectioned faciolingually along the root canal and the length of dye penetration was measured from the cementoenamel junction. Three-way ANOVA revealed that the dye penetration scores were influenced by post space preparation, resin coating, and temporization. Resin coating with RZ significantly reduced the dye penetration score and SE/PLF completely eliminated dye penetration.

Analysis of Variance↗

PubMed2006

[Late-onset urethrorectal fistula after laparoscopic radical prostatectomy: report of a case].

Urethrorectal fistula is a relatively rare disease. The most frequent cause of acquired urethrorectal fistulas is known to be iatrogenic complications, such as rectal injuries during the prostate operations. Rectal injuries are usually noticed during the operation and the majority can be repaired in situ. We report a case of late-onset urethrorectal fistula that lacked obvious rectal injury during the operation. Ischemic change or heat denaturation of rectal wall may be the potential cause of the present urethrorectal fistula.

Adenocarcinoma↗

PubMed2005

Shear bond strengths of indirect resin composites to hybrid ceramic.

A hybrid ceramic, Estenia, is a highly-filled composite for indrect use. The purpose of this study was to measure the shear bond strength between Estenia and six incremental materials: Estenia, Cesead II, Epricord, Gradia, Prossimo, and Solidex. Five specimens were prepared for each group, and all specimens were subjected to shear bond strength testing at a cross-head speed of 1 mm/min. Data were analyzed using two-way ANOVA and Dunnett's T3 test at 95% confidence level. The results indicated that the shear bond strength of Estenia to Estenia was significantly lower than that of any other combinations. Apart from storage condition that was found to influence shear bond strength statistically, thermal cycling of the specimens also tended to decrease the bond strength between Estenia and the incremental materials. It was concluded that regularly-filled composites are suitable to be used as an incremental material facing Estenia in combination technique.

Analysis of Variance↗

PubMed2005

Influence of curing method and storage condition on microhardness of dual-cure resin cements.

This study evaluated the influence of curing method and storage condition on the microhardness of dual-cure resin cements: Panavia F 2.0 (PF) and Nexus 2 (NX). The specimens were either light-cured (LC) or chemically cured in darkness (CC). After 24 hours of storage in dry chamber (Dry) or distilled water (DW), the specimens were sectioned and polished. The microhardness of resin cement matrix was measured using a nanoindentation tester (ENT-1100). The data (n = 6) were statistically analyzed with t-test, two-way ANOVA (p < 0.05), and Tukey HSD test (alpha = .05). It was found that the factors of curing method and storage condition had significant effect on microhardness. For both PF and NX, LC presented higher microhardness than CC, while DW showed higher microhardness than Dry. In conclusion, dual-cure resin cements could achieve high degree of cure when light-cured. In addition, the microhardness of the resin cements evaluated did not decrease when kept in water.

Analysis of Variance↗

PubMed2005

Effect of various grit burs on marginal integrity of resin composite restorations.

The purpose of this study was to evaluate the generation of enamel cracks and gaps at the cavosurface margin of resin composite restorations using various burs. Saucer-shaped cavities with a bevel were prepared on mid-coronal buccal or lingual surfaces of extracted human molars using a regular-grit round diamond bur, a fine-grit diamond bur, a superfine-grit diamond bur or a six-bladed tungsten carbide bur with an air turbine handpiece. The enamel margin of the cavity in each group was observed by a light microscope. Cavities were restored with a self-etching adhesive and a light-cured composite resin. After thermocycling, enamel cracks and gaps at the cavosurface margins were observed and scored. Specimens were sectioned longitudinally in two halves, and the resin-cavity interface was observed by means of a light microscope. In cavity preparation, the regular-grid diamond bur and the tungsten carbide bur caused more cracks in the marginal enamel than other groups. From the surface and sectioned surface observation of restored teeth, the superfine-grit diamond bur generated fewer cracks and gaps than the other burs.

Analysis of Variance↗

PubMed2005

Simplified and quantitative saliva buffer capacity test using a hand-held pH meter.

PURPOSE: To evaluate and compare saliva buffer capacity using a hand-held pH meter and a commercial buffer strip in patients at risk of caries. METHODS: To obtain stimulated saliva, 109 patients were given a paraffin wax to chew for 5 minutes. After reading the pH value of 0.5 ml of tested saliva using a portable hand-held pH meter (B-212), 10 microl of 0.1N HCl was titrated into the obtained saliva up to a total titration of 160 microl, and then the pH value read each time. The commercial buffer strip (CRT) was also evaluated. The correlation in ranking results (high, medium, low) between the B-212 pH meter and CRT buffer were statistically analyzed by the Bartlett's test (P < 0.001). RESULTS: At the point of 50 microd of titrated HCl, the individual saliva buffer capacities were ranked into one of the following three categories; high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). The percentages of the tested patients for the different ranks (high, medium, low) of buffer capacity were 50%, 17% and 33% respectively for the B-212 pH meter, and 56%, 17% and 27% respectively for the CRT. For the CRT buffer, 23 out of 109 cases showed inconclusive color change under the colorimetric test. There was significant correlation between ranking buffer capacity measured by the B-212 pH meter and the CRT buffer (P < 0.001).

Adult↗

PubMed2004

Microhardness and Young's modulus of a bonding resin cured with different curing units.

This study evaluated the microhardness and Young's modulus of a photocurable bonding resin, Clearfil SE Bond (SE), cured with four curing units at different distances. The curing units used were: Candelux (Quartz-tungsten halogen), Lux-O-Max (Blue light emitting diode), Arc-light (Plasma-arc), and Rayblaze (Metal halide). Discs of bonding resin were prepared using vinyl molds and were photocured at the top surface with light tip at three different distances (contact, 2 and 4 mm). After 24 hours of storage in water at 37 degrees C, the specimens were sectioned into halves, embedded in epoxy resin, and polished. The microhardness and Young's modulus of this bonding resin were measured using a nanoindentation tester. Six specimens were prepared for each group. The data was statistically analyzed using two-way ANOVA test and Tukey multiple comparison test (p < 0.01). The microhardness of SE was affected by light source and distance, as was Young's modulus. Candelux and Rayblaze presented the highest hardness and Young's modulus results. Both properties presented high values when the curing unit tip was maintained in contact with the irradiated surface. Increasing the distance between the curing unit tip and the irradiated surface decreased the hardness and Young's modulus of SE.

Analysis of Variance↗

PubMed2004

Surface analysis of dentinal caries in primary teeth using a pH-imaging microscope.

The aim of this in vitro study was to evaluate the pH value of intact and carious dentin in primary teeth using a pH-imaging microscope (SCHEM-100, HORIBA Ltd., Kyoto, Japan). Bucco-lingual cut sections of extracted human primary teeth, which had either mild or severe dentinal caries lesions, were placed on the pH-imaging sensor of the microscope. The pH values were compared statistically by Levene's test for equality of variances and Tukey HSD multiple comparison test (p < 0.05). For both mild and severe lesions in primary dentin, the lowest pH values in the carious lesions were lower than those of intact dentin (6.6, range 6.3-6.9). There were statistical differences between the lowest pH value within the mild lesions (6.2, range 5.8-6.4) and that of the severe lesions (6.0, range 5.9-6.2) (p < 0.05). It was concluded that SCHEM-100 was able to distinguish the pH-value distribution of intact and carious dentin in primary teeth.

Analysis of Variance↗