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Masanori Hashimoto

Publications and source records attributed to Masanori Hashimoto.

32 records · Page 2Linked to original sources
PubMed2004

In vitro testing of all-in-one adhesives as fissure sealants.

PURPOSE: To evaluate the clinical efficacy of all-in-one adhesives as fissure sealants. METHODS: Resin-enamel bonded specimens were fabricated between polished and ground enamel surfaces using two all-in-one adhesives (One-Up Bond F and Xeno CF Bond) and two resin sealants (Teethmate F-1 and Helioseal F). Specimen beams were prepared and microtensile bond tests were performed at a crosshead speed of 1 mm/minute. The bond strengths obtained were subjected to one-way ANOVA and Scheffe's F test (P < 0.05: n=12 for each group). To evaluate the etching effect of phosphoric acid and the all-in-one adhesives, the treated enamel surfaces (37% phosphoric acid, 40% phosphoric acid, or all-in-one adhesives) were examined by FE-SEM. RESULTS: The bond strengths of the two all-in-one adhesives tested to the polished enamel surface were significantly lower (P < 0.05) than to ground enamel. However, no significant differences (P > 0.05) were found between the polished and ground enamel surfaces for resin sealants using phosphoric acid. Under SEM examination, 37% or 40% phosphoric acid etched the enamel surface more than all-in-one adhesives.

Acid Etching, Dental↗
PubMed2004

Nanoleakage types and potential implications: evidence from unfilled and filled adhesives with the same resin composition.

PURPOSE: To compare nanoleakage patterns of an unfilled (OS; One-Step), a 6 wt% spherical silica-filled (OSs; One-Step Plus) and a 15 wt% glass-filled (OSg) version of a two-step, acetone-based self-priming adhesive. Permeability of bonded dentin treated with OS and OSs was also examined. METHODS: Deep, coronal dentin from extracted third molars were etched and bonded using these adhesives. One-mm thick sections were immersed in 50 wt% ammoniacal silver nitrate (pH 9.5) for 24 hours. Unstained, undemineralized sections were examined by TEM. The permeability of dentin bonded with OS and OSs were investigated at 20 cm of H2O hydrostatic pressure and compared with the osmotic conductance determined with 4.8 M CaCl2 at zero hydrostatic pressure. Composite-dentin beams bonded with OS, OSs and OSg that were fractured after microtensile bond testing were examined by SEM. RESULTS: Two types of nanoleakage patterns were recognized along the resin-dentin interfaces. The reticular type consisted of discontinuous islands of silver deposits and was exclusively seen in hybrid layers. The spotted type consisted of isolated silver grains and was evident throughout the hybrid and adhesive layers in OS. These two patterns were seen to variable extents in the two filled adhesive versions OSs and OSg and their distribution was independent of one another. OS and OSs bonded dentin were permeable to fluid filtration. However, part of this fluid movement was due to the permeability of the adhesive layer, as demonstrated by osmotic fluid conductance in the absence of hydrostatic pressure. Fractographic analysis revealed denuded collagen fibrils within fractured hybrid layers that were indicative of incomplete resin infiltration.

Acetone↗
PubMed2003

Degradation patterns of different adhesives and bonding procedures.

Various types of resin adhesives and procedures are available in the clinical field, so comprehensive understanding of degradation is required for each material and bonding procedure. The objective of this study was to investigate the bond durability for different adhesives and bonding procedures. Resin-dentin bonded beams were prepared with the use of two adhesives (One-Up Bond F/self-etching primer system and One Bond/total-etch adhesive) and two experimental groups for the bonding procedure (wet and dry bonding of the total-etch adhesive). Those samples were soaked in water for 24 h(control), 6 and 12 months. After the water immersion, the bond strengths were measured by the microtensile bond test, and subsequently fractography was performed with the use of SEM. Statistically significant reduction of the bond strength (p < 0.05) was apparent after 12 months of water exposure in the range 22-48% of the control. The bonding resin was eluted from the hybrid layer of the self-etching and the total-etch adhesives for the wet bonding. Micromorphological alterations were found due to the hydrolysis of collagen fibrils with the total-etch adhesive for the dry bonding mode. These pathologic alterations were in accord with the bond strength.

Adhesives↗
PubMed2003

SEM and TEM analysis of water degradation of human dentinal collagen.

Recently several long-term studies have reported evidence of the hydrolytic degradation of collagen fibrils based on fractured surface observations after bond testing. Those studies suggested that one cause of the decline in the bond strength was the degradation of the collagen fibrils within the bonds. However, one concern has been raised that the dentinal collagen fibrils may be stable in water that does not contain oral bacteria or enzymes. Therefore, the present study aimed to clarify the micromorphological change in naked collagen fibrils after 500 days of water storage. To prepare exposed collagen fibrils, sectioned and polished human dentin surfaces were acid conditioned for 15 s with the use of two commercially available acid conditioners: All-Etch (10% phosphoric acid) and Uni-Etch (32% phosphoric acid) (Bisco, Inc.). Those specimens were stored in distilled water at 37 degrees C for 1 day (control) for 500 days. After the storage periods, the samples were examined with the use of SEM and TEM. Under SEM and TEM examination, micromorphological alterations (disarrangement of collagen web, widening the interfibrillar space, and the thinning diameter of collagen fibrils) were found in the specimens after 500 days in water.

Acid Etching, Dental↗
PubMed2003

[Treatment of subarachnoid hemorrhages in an isolated mountainous area].

From January 1997 to December 2001, patients with subarachnoid hemorrhage (SAH) among 14,008 residents in an isolated mountainous area; Oguni and Minamioguni towns in Kumamoto Prefecture, were evaluated. The subjects were patients being treated at Oguni Municipal Hospital. Over a period of 5 years, 19 patients were found to be suffering from SAH in this area, 3 of whom were visitors (residing outside this area). The annual incidence rate of SAH in this area was calculated as 22.9 per 100,000. The sex ratio (men:women) was 4:12. The average age was 67.9 years; 65.0 years for men and 68.8 years for women. Eleven patients were older than 65, and constituted 68.8% of the subjects. The risk factors of SAH were recognized, and both hypertension and smoking constituted 31.6%. Alcohol was 21.1% and hyperlipemia was 15.8%. In 13 clipping operated cases excluding 1 test craniotomy, Hunt & Kosnik's Grades at admission were G.I: 2, G.II: 5, G.III: 3, G.IV: 2 and G.V: 1, and Fisher's Groups were G.I: 0, G.II: 8, G.III: 3 and G.IV: 2. The sites of 16 operated aneurysms were internal carotid-posterior communicating artery (IC-PC): 2, anterior communicating artery (A Co.A): 4, middle cerebral artery (MCA): 10 and vertebral artery-basilan artery (VA-BA): 0. The aneurysmal size were < 5 mm: 5, 6-10 mm: 9 and 11 mm < :2 (average 7.6 mm, 2-15 mm). The results were evaluated at discharge, excluding 1 SAH of unknown etiology. 9 were good, 2 were dependent and 7 including 5 non-operative cases had died. We were satisfied with these results, because we were treating older patients. Although we attempted the clipping operation using only a three dimensional computed tomographic angiograply (3D-CTA; X-Vision GX (TOSHIBA) & X-Tension), we had no problem, except for 1 test craniotomy. 3D-CTA was useful during the clipping operation in the small hospital, especially, in regard to cost.

Aged↗
PubMed2003

Diabetic mastopathy in an advanced elderly woman with insulin-dependent type 2 diabetes mellitus.

Diabetic mastopathy is an unusual stromal fibrotic lesion, but typically occurs in long-standing insulin dependent and younger diabetic patients. We report a case of diabetic mastopathy in an older diabetic patient. The patient was a 76-year-old woman with a history of type 2 diabetes mellitus for 13 years and 3 years of insulin treatment. She developed a 3 cm, hard, mobile nodule in the left breast. Mammography revealed a dense mass. Ultrasonography showed an irregular-shaped hypoechoic lesion with an unclear boundary and acoustic shadowing. Since fine needle aspiration biopsy delivered insufficient material and core needle biopsy did not yield any specific findings for diagnosis, clinically diabetic mastopathy was the prime suspect but breast cancer could be completely ruled out. Surgical excision was thus performed and diabetic mastopathy was confirmed pathologically. We report on this rare case of diabetic mastopathy in a 76 year-old type 2 diabetic patient.

Aged↗
PubMed2003

In vitro degradation of resin-dentin bonds analyzed by microtensile bond test, scanning and transmission electron microscopy.

Our knowledge of the mechanisms responsible for the degradation of resin-dentin bonds are poorly understood. This study investigated the degradation of resin-dentin bonds after 1 year immersion in water. Resin-dentin beams (adhesive area: 0.9mm(2)) were made by bonding using a resin adhesive, to extracted human teeth. The experimental beams were stored in water for 1 year. Beams that had been stored in water for 24h were used as controls. After water storage, the beams were subjected to microtensile bond testing. The dentin side of the fractured surface was observed using FE-SEM. Subsequently, these fractured beams were embedded in epoxy resin and examined by TEM. The bond strength of the control specimens (40.3+/-15.1MPa) decreased significantly (p<0.01) after 1 year of water exposure (13.3+/-5.6MPa). Loss of resin was observed within fractured hybrid layers in the 1 year specimens but not in the controls. Transmission electron microscopic examination revealed the presence of micromorphological alterations in the collagen fibrils after 1 year of water storage. These micromorphological changes (resin elution and alteration of the collagen fibrils) seem to be responsible for the bond degradation leading to bond strength reduction.

Biocompatible Materials↗
PubMed2003

Resin-enamel bonds made with self-etching primers on ground enamel.

Self-etching primer adhesives have recently been introduced to simplify bonding. However, the fundamental bonding mechanism of self-etching primers to enamel is not yet fully understood. This study aimed to investigate resin-enamel bonds of self-etching primer adhesives on ground enamel. Two self-etching primer adhesives (Clearfil Liner Bond 2 V and Clearfil SE Bond) were used in this study. A total-etch adhesive (One-Step) was used as a control. Resin-enamel beams were subjected to the microtensile bond test. Subsequently, the failure modes of all specimens were quantified using image analysis. Undemineralized and demineralized ultrathin sections of the resin-enamel bonded specimens were examined using transmission electron microscopy. The bond strengths of Clearfil SE Bond (39.8 +/- 11.9 MPa) and One-Step (46.2 +/- 12.7 MPa) were significantly greater than that of Clearfil Liner Bond 2V (30.4 +/- 6.2 MPa). Scanning electron microscopy of the fractured surfaces revealed the failure direction and weakest portion within each bond. Transmission electron microscopy showed a thin hybridized complex of resin in enamel produced by the self-etching primers without the usual micrometer-sized resin tags seen in resin-enamel bonds produced using the total-etch adhesive. The morphological features of the resin-enamel bonds produced by two self-etching primers tested were different from that created with the total-etch adhesive.

Adhesives↗
PubMed2003

Clinical application of human telomerase reverse transcriptase gene expression in thyroid follicular tumors by fine-needle aspirations using in situ hybridization.

Most of fine-needle aspiration (FNA) biopsies for follicular tumors of the thyroid are deemed 'indeterminate' or 'suspicious' with regard to malignancy, even though most of these lesions are benign. Therefore, additional diagnostic markers of malignancy are needed. Telomerase activity is present in most malignant tumors. Expression of the gene encoding human telomerase reverse transcriptase (hTERT) is very closely associated with telomerase activity, this gene is overexpressed in most thyroid carcinomas. We examined telomerase activity by the telomeric repeat amplification protocol (TRAP) and hTERT gene expression by in situ hybridization (ISH) in thyroid tissue including 6 follicular carcinomas and 15 follicular adenomas. ISH for hTERT gene was performed using FNA samples from the same patients. Telomerase activity was detected in all six of the follicular carcinomas and in five (33%) of the 15 follicular adenoma tissue specimens. hTERT gene expression was detected the follicular cancer cells in all of the lesions and in one (7%) of the 15 thyroid adenomas. Moreover, we demonstrated that hTERT gene expression was occurring in four (67%) of the 6 follicular carcinoma biopsy specimens obtained using FNA. These results suggest that the detection of hTERT gene expression using ISH tissue specimens can be used to distinguish between benign and malignant follicular lesions of the thyroid, however the detection of hTERT gene in FNA samples using ISH cannot be used to definitively diagnose follicular tumors of the thyroid.

Adenocarcinoma, Follicular↗
PubMed2002

Micromorphological changes in resin-dentin bonds after 1 year of water storage.

The purpose of this study was to evaluate the degradation of resin-dentin bonds after 1 year of water storage. Resin-dentin-bonded specimens were prepared with the use of an adhesive resin system (One-Step: Bisco). Half of the experimental specimens were sectioned perpendicular to the adhesive interface to produce a beam (adhesive area: 0.9 mm(2)) before being stored in distilled water at 37 degrees C for 1 year. The remaining half of the bonded specimens were sectioned into beams of similar dimensions after 1 year of water storage. Additional bonded specimens that had been stored in water for 24 h before sectioning into beams were used as controls. The beams in the two experimental groups and the control group were subjected to microtensile bond testing. Fractography was performed on all fractured beams with the use of FE-SEM. There were significant (p <.05) differences in bond strength among the control specimens (55.9 +/- 12.9 MPa), specimens that had been sectioned into beams after water storage (68.9 +/- 18.6 MPa), and specimens that had been sectioned into beams before water storage (28.1 +/- 9.3 MPa). Fractography revealed that the resin material was gradually extracted from the periphery to the center portion of the beam. This probably accounted for the decrease in bond strength after 1 year of water storage.

Bicuspid↗
PubMed2002

Ruptured aneurysm associated with partially duplicated posterior communicating artery--case report.

A 65-year-old woman presented with a ruptured saccular aneurysm associated with a rare variation of the posterior communicating artery (PcoA), partially duplicated PcoA. The PcoA with this variation forked just distal to the aneurysmal neck, and the two branches independently merged into the posterior cerebral artery. Initial clipping failed to isolate the aneurysm from one of the two branches, so the aneurysmal dome continued to pulsate and bleed. Temporary clipping of the proximal internal carotid artery revealed the fork of the two branches just distal to the aneurysmal neck. A curved Yasargil clip was used to clip the aneurysm and preserve the PcoA and branches. Careful observation of this PcoA variation is needed because the arterial structures may be hidden by the thickened arachnoid membrane.

Aged↗
PubMed2002

[Hypoplasia of internal carotid artery at cervical portion associated with neurofibromatosis type I].

Congenital absence of the internal carotid artery (ICA) is a rare anomaly and aplasia/hypoplasia of the ICA associated with other congenital malformations is uncommon, too. We report a very rare case of hypoplastic carotid canal due to hypoplastic ICA at cervical portion associated with neurofibromatosis type I (NF I). A 22-year-old male with NF I was admitted to our hospital for transient weakness of the left upper and lower limbs. Computed tomography (CT) of the brain demonstrated no abnormal findings. But bone target CT and three dimensional computed tomography (3 D-CT) showed a hypoplasia of right carotid canal. Cerebral angiography revealed that the right ICA was hypoplastic at its cervical portion and occluded at the carotid canal. Rest single photon emission computed tomography (SPECT) demonstrated normal cerebral perfusion, and SPECT with acetazolamide demonstrated showed cerebral perfusion reserve of both hemispheres, too. So he was treated conservatively at the present time. Careful follow up should be performed for such patients, because they are very rare cases and the natural history of them is unknown, too.

Adult↗
PubMedDate not supplied

Effects of multiple adhesive coatings on dentin bonding.

Simple changes to bonding techniques can improve resin-dentin bond strengths. This study evaluated the effect of multiple consecutive coatings of adhesive resin on dentin by measuring both microtensile bond strength and nano-leakage following exposure to ammoniacal silver nitrate. Resin-dentin bonded specimens were prepared using two total-etch adhesives (OptiBond Solo Plus/Kerr or Single Bond/3M ESPE). During bonding, resin application and air evaporation were done 1, 2, 3, 4, 6 or 8 times on acid-etched, moist dentin surfaces. Mean microtensile bond strengths were evaluated by two-way ANOVA and Fisher's PLSD test (p<0.05; n=16 for each group). Additionally, nanoleakage of silver nitrate was evaluated by transmission electron microscopy (TEM). The results indicated that bond strengths increased with each coating up to four coats. Nanoleakage decreased with each coat, becoming very small after four or more coats. This adhesive application method can be easily applied to clinical practice, thereby improving the quality of resin-dentin bonds.

Bicuspid↗