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Biomedical subjects

J Tagami

Publications and source records attributed to J Tagami.

At least 73 records · Page 4Linked to original sources
PubMed1997

Shear bond strengths of a single-step bonding system to enamel and dentin.

An experimental primer was developed as a single-step bonding system for resin-modified glass ionomer cements (GIC). Efficacy of this primer on adhesion of resin-modified GICs and resin composite to enamel and dentin was evaluated by shear bond test and SEM observation. Good bond strengths to enamel were obtained (> 11 MPa), whereas significantly low bond strengths to dentin were obtained using a single coat of the primer. However, double-coating improved the bond strengths to dentin (> 8 MPa). SEM observations indicated that the primer functioned as a mild conditioner to remove the smear layer on enamel or dentin surfaces. A hybrid layer was observed at the cross-sectional view of the GIC/dentin interface. These findings suggested that good adhesion to enamel and dentin could be achieved using a single-step bonding system.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1997

Bond strength and interface micromorphology of an improved resin-modified glass ionomer cement.

PURPOSE: To evaluate the influence of surface treatment with 20% polyacrylic acid containing 3% aluminum chloride (AlCl3) on the shear bond strength of an improved resin-modified glass ionomer cement to enamel and dentin, and to analyze the micromorphology of the cement-tooth interface. MATERIALS AND METHODS: Flat enamel and dentin surfaces of bovine incisors were ground up with sequentially finer abrasives to 1000-grit silicon carbide paper. Each surface was treated with 10% polyacrylic acid (Dentin Conditioner: DC) for 20 seconds or with 20% polyacrylic acid containing 3% aluminum chloride (Cavity Conditioner: CC) for 10 seconds, rinsed, and gently air-dried. A resin-modified glass ionomer cement (Fuji II LC) and its improved version (Fuji II LC-I) were applied to the tooth substrate, and bond strengths measured at periods of 5 minutes, 1 day, and 1 week after light curing. As a control, the resin-modified glass ionomer cements were applied to untreated surfaces and were tested at 1 day. To evaluate the interface micromorphology, specimens were prepared following the adhesive-sandwich technique, cut in equal halves, and observed under a scanning electron microscope (SEM). Additionally, in order to observe the effect of surface pre-treatment of each conditioner on dentin, pre-treated dentin disks were freeze-dried, fractured, and the morphology of the treated and fractured surfaces were observed. RESULTS: Shear bond strength of CC+ Fuji II LC-I to enamel was significantly higher than that of DC+ Fuji II LC at 1 day and 1 week (P < 0.0001). As for dentin, the improved system showed significantly higher bond strength at 5 minutes after light curing (P < 0.001), but bond strengths were not statistically different at 1 day and 1 week. Fracture patterns, examined with a stereomicroscope, were mixed adhesive/cohesive within the cement for all groups. Interface micromorphology, observed with an SEM, suggested the formation of a resin-rich layer and an indistinct zone between the resin-modified glass ionomer cements and the underlying dentin.

Acid Etching, Dental↗
PubMed1996

Dentin bond durability after three years using a dentin bonding agent with and without priming.

OBJECTIVES: This three-year study was conducted to evaluate the tensile bond strengths of a dual-cured bonding resin, with and without priming, to bovine dentin. METHODS: Superficial bovine dentin was conditioned with 37% phosphoric acid and left unprimed (control) or was primed with 5-NMSA. Clearfil Photobond (Kuraray Co., Japan) was placed and light-cured, a layer of Protect Liner (Kuraray Co.) was applied, cured, then covered with Photo Clearfil Bright (Kurary Co.) resin composite and cured. Bonds were stressed in tension to failure at 1 d, 1 mon, 3 mon, 6 mon, 1 y and 3 y after preparation. Ten specimens were made for each group. Results were analyzed using one-way ANOVA and Duncan's multiple range test. Visual and SEM observations determined mode of failure and were analyzed using the Mann-Whitney U-test. Separate 1 d and 3 y specimens were fractured across the bonded interface and observed using a Field Emission SEM. After observation, the photomicrographs were compared for visual qualitative changes between the two time periods. RESULTS: The control (non-primed) group showed only a small decrease in bond strengths over 3 y, but in the primed group, a significant decrease was observed (p < 0.05). The bond strength of the non-primed group (5.2 MPa) was less than the primed group (10.6 MPa) at 1 d (p < 0.01), but by 3 y, the bonds of both groups were similar, 4.3 MPa and 5.5 MPa, respectively. Fractography indicated that only adhesive failure occurred in the control group. Failure in the primed group was cohesive in dentin initially, but shifted to the base or top of the hybrid layer after 1 y. Field Emission SEM observations showed hybrid layer formation in the primed group, but minimal resin infiltration in the control group. SIGNIFICANCE: Initially greater bond strengths were obtained for the primed group compared to the unprimed group (p < 0.01). However, by 3 y, the bond strength had decreased markedly in the primed group (p < 0.01), being almost the same for both groups. It was concluded that priming may only be useful to achieve strong bonding in the short term. These results may have significant implications related to clinical longevity of restorations.

Analysis of Variance↗
PubMed1996

Regional strengths of bonding agents to cervical sclerotic root dentin.

The regional bond strengths of three current-generation bonding systems (All Bond 2, Scotchbond Multi-Purpose, and Clearfil Liner Bond 2) were measured in natural wedge-shaped defects in the cervical area of extracted human teeth. A microtensile testing method was used to compare the strengths of resin bonds made to occlusal margins with those made to gingival margins. Controls consisted of normal teeth which had artificial wedge-shaped defects, of the same depth and dimension, created with a high-speed bur. The results indicated that there were no regional differences in bond strength, although bonds made to natural lesions were from 20 to 45% lower than those made to normal dentin in artificially created wedge-shaped defects, depending on the bonding agent. Scanning electron microscopy revealed that Clearfil Liner Bond 2 created the thinnest hybrid layers, which were difficult to measure in the natural lesions. The natural lesions contained sclerotic dentin, whereas the artificial lesions were composed of normal dentin. Although the bond strengths to sclerotic dentin were lower than those to normal dentin, the absolute values (ca. 16 to 17 MPa) were high relative to previous-generation bonding agents.

Acid Etching, Dental↗
PubMed1996

Bond strength to crown and root dentin.

PURPOSE: To investigate (1) the tensile bond strengths of four commercial dentin bonding systems to bovine crown and root dentin and (2) the structure of the hybrid layers for each system bonded to the two dentin substrates. MATERIALS AND METHODS: Superficial surfaces were exposed in bovine crown and root dentin. The teeth were embedded in plaster and a 3 mm diameter bonding area was demarcated. The four bonding systems used were All-Bond 2, Super-Bond D-Liner Plus, Clearfil Liner Bond II, and ProBond. Bonding procedures followed the manufacturers' instructions with the exception of Super-Bond D-Liner Plus where the primer was left in situ for 60 seconds. Tensile bond strengths were tested after 24-hour storage in 37 degrees C deionized water. Specimens were also prepared for SEM observation of the hybrid layer, after treatment with 10% phosphoric acid, and 10% phosphoric acid and 5% sodium hypochlorite. RESULTS: Statistically lower bond strengths to crown dentin when compared with root dentin were observed for All-Bond 2, whereas Liner Bond II showed the opposite (P < 0.01). Both ProBond and Super-Bond D-Liner Plus showed no statistical differences between crown and root dentin (P > 0.05). Hybrid layers could be observed for All-Bond 2, Liner Bond II and Super-Bond D-Liner Plus, with no apparent differences between the hybrid layers of crown and root dentin. In the case of ProBond, where the smear layer was not removed during the priming stage, it appeared that the primer had infiltrated and caused hybridization of the smear layer. The differences in bond strength were thought to be related to the different bonding mechanisms of each material, as well as possible variations in the crown and root dentin substrates.

Acid Etching, Dental↗
PubMed1995

Influence of temperature and relative humidity on early bond strengths to dentine.

The effect of temperature and relative humidity (RH) on the early tensile bond strengths to bovine dentine of two bonding systems (Liner Bond System, and Scotchbond Multi-purpose), and an experimental system (KB-110) were tested. Two environmental conditions, room temperature (23 degrees C/50% RH) and oral temperature (30 degrees C/80% RH), were used in a controlled temperature and humidity chamber. Bond strengths were recorded immediately after, 10 min and 24 h following light curing. The tensile bond strengths did not vary between the two test conditions, but the mode of fracture was observed to change. The 30 degrees C/80% RH condition exhibited a slightly greater degree of adhesive type failures compared with the 23 degrees C/50% RH group. This was particularly so for the experimental system, indicating that different bonding systems may be more or less sensitive to changes in RH and temperature. Failures occurred partially or totally within the resin composite at the early test times, and it was concluded that the bond strengths of the systems tested tended to exceed the early cohesive strengths of the resin composite.

Adhesiveness↗
PubMed1995

Tensile bond strength and SEM evaluation of caries-affected dentin using dentin adhesives.

Tensile bond strength measurements are commonly used for the evaluation of dentin adhesive systems. Most tests are performed using extracted non-carious human or bovine dentin. However, the adhesion of resins to caries-affected dentin is still unclear. The objectives of this study were to test the hypothesis that bonding to caries-affected dentin is inferior to bonding to normal dentin, and that the quality of the hybrid layer plays a major role in creating good adhesion. We used a micro-tensile bond strength test to compare test bond strengths made to either caries-affected dentin or normal dentin, using three commercial adhesive systems (All Bond 2, Scotchbond Multi-Purpose, and Clearfil Liner Bond II). For scanning electron microscopy, the polished interfaces between the adhesive bond and dentin were subjected to brief exposure to 10% phosphoric acid solution and 5% sodium hypochlorite, so that the quality of the hybrid layers could be observed. Bonding to normal dentin with either All Bond 2 (26.9 +/- 8.8 MPa) or Clearfil Liner Bond II (29.5 +/- 10.9 MPa) showed tensile bond strengths higher than those to caries-affected dentin (13.0 +/- 3.6 MPa and 14.0 +/- 4.3 MPa, respectively). The tensile bond strengths obtained with Scotchbond Multi-Purpose were similar in normal and caries-affected dentin (20.3 +/- 5.5 MPa and 18.5 +/- 4.0 MPa, respectively). The hybrid layers created by All Bond 2 in normal dentin and by Clearfil Liner Bond II in normal or caries-affected dentin showed phosphoric acid and sodium hypochlorite resistance, whereas the hybrid layers created by All Bond 2 in caries-affected dentin and those created by Scotchbond Multi-Purpose to normal and caries-affected dentin showed partial susceptibility to the acid and sodium hypochlorite treatment. The results indicate that the strength of adhesion to dentin depends upon both the adhesive system used and the type of dentin. Moreover, the quality of the hybrid layer may not always contribute significantly to tensile bond strength.

Analysis of Variance↗
PubMed1995

Effect of pulpal pressure on adhesion of resin composite to dentin: bovine serum versus saline.

The purpose of this study was to compare the tensile bond strengths of resin composite to dentin, mediated by two new bonding systems (Scotchbond Multi-Purpose and Clearfil Liner Bond II), under simulated pulpal pressure when diluted bovine serum or saline was used as the pulpal fluid. The bond strengths of the two bonding systems to dentin (under a pulpal pressure of 15 cm of water) obtained when bovine serum was used were statistically significantly higher than those obtained when saline was used. These data suggest that the primers of these bonding systems decreased the dentinal permeability when the bovine serum pulpal fluid was used through the precipitation of serum proteins by the primers in the dentinal tubules. This may have allowed better penetration of the bonding resin monomers into the conditioned dentinal structure, thus improving the bond strength. These findings support the idea that topical application of dentinal bonding systems may be an effective therapy for treating hypersensitive dentin.

Animals↗
PubMed1994

The influence of age and depth of dentin on bonding.

OBJECTIVES: The purpose of this study was to investigate what influence the two variables of dentin depth and age may have on the tensile bond strengths of three bonding systems. METHODS: Dentin discs prepared from human molars were divided into young and old, superficial and deep surfaces. Three bonding systems, Scotchbond Multi-purpose (3M Dental Products), Superbond D-liner (Sun Medical Co.), and Liner Bond II (Kuraray Co.) were the materials tested for tensile bond strength. In addition, the structural variation of the resin-impregnated, or hybrid, layer was compared among the two variables and three bonding systems. RESULTS: Tensile bond strengths exceeding 10 MPa were obtained for all materials. After ANOVA, an effect on tensile bond strength could be attributed to dentin age or depth for only Superbond D-liner used on deep-young dentin as compared with old-superficial dentin. All other group comparisons failed to show any variation between dentin depth or age. However, specimens bonded to deeper dentin showed slightly lower strengths. SEM observations showed thicker resin-impregnated layers for Scotchbond MP and Superbond D-liner compared with Liner Bond II. Liner Bond II exhibited a thinner and more diffuse resin-impregnated layer, believed to be due to the different dentin conditioning method. SIGNIFICANCE: Dentin age or depth may not show as great an influence on bond strengths with the newer type of bonding systems. The resin-impregnated layer quality, rather than thickness, is believed to be the most important factor for obtaining high tensile bond strengths.

Age Factors↗
PubMed1994

Early tensile bond strengths of several enamel and dentin bonding systems.

Tensile bond strength tests are commonly used for the evaluation of adhesive dental materials. The majority of these tests are carried out after 24 h of storage in water. However, determination of the early tensile bond strength could be more important, especially in relation to gap formation between the cavity surface and the restorative material. This study investigated the tensile bond strengths of five enamel/dentin bonding systems and two experimental dentin bonding systems. Tensile bond strengths were obtained at one min, ten min, and 24 h after the resin composite was cured. Bond strengths at the early stages were always somewhat less than the 24-hour test results. For the enamel/dentin bonding systems, a significant difference was found between the enamel and dentin bond strengths at all time periods, except with Superbond D-liner and Liner Bond. The experimental group with glyceryl methacrylate as the primer produced a good 24-hour result (14.3 MPa), but the early bond strengths were no different from those in the non-primer-treated groups. It was concluded that this material may actually retard the polymerization of the bonding resin. Previous workers have suggested that a tensile bond strength in the order of 20 MPa is necessary for gap-free restorations to be obtained. Should this be the case, then all of the materials tested, from the aspect of early bond strength, lack the strength for prevention of gap formation, although Superbond D-liner and Liner Bond approached this hypothetical figure. These systems, Superbond D-liner and Liner Bond, also exhibit small differences between the enamel and dentin tensile bond strengths.

Analysis of Variance↗
PubMed1993

Tensile bond strength and curing gap formation of a dentin bonding resin.

Tensile bond strength and contraction gap tests were carried out using a new dentin bonding resin in association with various dentin conditioning and priming materials in vitro. For the tensile bond test, significant differences were found between the nonconditioned and conditioned dentin, and the primed and non-primed dentin surfaces. The strongest bond was obtained using a combination of phosphoric acid conditioning and priming with HEMA in glutaraldehyde at 151.3 kgf/cm2. Gap test results showed the presence of gaps in all of the test groups, but with variation in the extent of gap formation. A not significant, inverse correlation was determined between the tensile bond strength and gap tests (R = -0.65). The new bonding resin obtained good bond strengths in all cases, but high bond strengths can only be obtained with a combination of etching and priming. Similarly, the smallest gaps were associated with the etched and primed groups.

Animals↗
PubMed1993

Effect of aging on dentin bonding.

The purpose of this paper was to evaluate the effect of aging of dentin on the tensile bond strengths of four dentin bonding systems using proximal dentin of premolars extracted from young (aged from 9-21 years) and old (aged from 42-64 years) patients. Clearfil Linerbond System and Super Bond D-Liner showed higher bond strengths to both young and old teeth than those of Clearfil Photo Bond and Resto Bond 3. However, similar bond strengths to both young and old teeth for all four products were obtained despite the effects of aging. Furthermore, a SEM study of the site of bond failure revealed the persistence of the resin impregnated layer on the dentin surface, in spite of the difference of bonding system and dentin, indicating that adhesive failure tended to occur at the interface between the bonding resin and the resin impregnated layer.

Adolescent↗
PubMed1993

The long term durability of bond strengths to dentin.

The aim of this study was to investigate the durability, throughout one year, of tensile bond strengths (TBS) to bovine dentin using various commercial and experimental bonding systems. Specimens were stored in a controlled solution of ion-exchanged water containing plaster chips and sodium azide. From the results it was concluded that the changes in TBS were not uniform over time, but a significant decrease was usually observed. For Super Bond D-liner and KB-100, the TBS were the highest and exhibited remarkable stability over the test period. The mode of fracture was noted to vary depending on the treatment system used, and was independent of TBS. Generally, the fracture mode tended to show increases in adhesive/cohesive failures within the resin over time. Super Bond D-liner always exhibited adhesive type failure at the tooth interface, and later involved failure in the hybrid layer. KB-100 showed very little change in failure over one year, being usually adhesive between bonding resin and resin composite. The results from this study indicate the need to carry out durability studies for the basic evaluation of all bonding systems. It was shown that the use of a controlled storage solution is important.

Acid Etching, Dental↗
PubMed1992

Effect of aging and caries on dentin permeability.

Extracted human teeth were collected from young (20-28 yrs) versus old (45-69 yrs) patients. The teeth were divided into carious and noncarious groups. Slabs were created from the mid-coronal occlusal dentin. Carious lesions were excavated and the smear layers on both normal and excavated carious dentin were removed with 37% phosphoric acid (1 min). The permeability (hydraulic conductance) of old normal dentin was only 20% of that obtained in young normal dentin but all of the specimens were permeable. Young carious dentin was only 14% as permeable as young normal dentin and only 1 out of 7 specimens was not permeable. All 7 specimens of old carious dentin were impermeable. Scanning electron microscopy of old and carious dentin exhibited far more intratubular crystals than normal dentin, providing a structural basis for the functional observation.

Adult↗
PubMed1991

Effects of high-speed cutting on dentin permeability and bonding.

The effects of high-speed cutting by use of a diamond bur with or without water coolant or sanding by 80-grit SiC paper on dentin permeability, before and after surface treatment, and dentin bonding of adhesive resins were compared. Three different bonding systems were used: Scotchbond DC, which requires no removal of smear layers, and two others, Clearfil Photobond and Superbond C&B, both of which remove smear layers (phosphoric acid gel or 10% citric acid containing 3% ferric chloride, respectively). Creation of smear layers by bur cutting or sanding reduced dentin permeability to levels that were only 1-3% of the maximum permeability values. Scotchbond DC gave low but consistent bond strengths (3.7-6.1 MPa) to dentin covered with smear layers. Clearfil PHotobond also produced consistent bond strengths (8.6-9.4 MPa). The increase in the permeability of dentin after phosphoric acid treatment was higher when the SiC paper was used (146%) than when the high-speed bur was used (87-90%). The smear layer and smear plugs produced by the diamond bur were more resistant to 10-3 treatment than were the SiC-created smear layers. The bond strengths of Superbond showed the highest bond strengths to the conditioned dentin when the high-speed cutting was used with water coolant (16.3 MPa), compared with the other two groups (12.2-12.5 MPa).

Analysis of Variance↗
PubMed1991

Pulpal pressure and bond strengths of SuperBond and Gluma.

The effects of storage under a simulated pulpal pressure on the shear bond strength of SuperBond and Gluma were evaluated using extracted, unerupted human teeth. Also evaluated was the effect of dentin position both vertically (i.e., superficial versus deep) and horizontally (center versus pulp horns) in the presence or absence of a pulpal pressure. Thirty-two cm of H2O pressure had no effect on the 24 hour shear bond strength of SuperBond C & B. There was also no significant difference in the bond strength of SuperBond to superficial versus deep dentin or central dentin versus dentin directly over pulp horns. The bond strengths of SuperBond ranged from 16.3-19.1 MPa. Gluma bonds were less than half as strong as those obtained with SuperBond C & B. Although there was no effect of dentin position on Gluma bond strength, in the presence of a pulpal pressure, the strength of the bonds fell in deep dentin especially over pulp horns. This testing protocol may prove of value in screening new dentin bonding systems.

Boron Compounds↗
PubMed1990

Correlation among dentin depth, permeability, and bond strength of adhesive resins.

Correlations among dentin permeability, dentin depth, and dentin bonding of Scotchbond, Clearfil New Bond, and Superbond C&B were studied in bovine incisor crown segments. Since the dentin surface was prepared on deeper dentin, the permeability of the dentin increased both in the presence of, and especially after removal of, the smear layer. In general, the deeper the dentin, the lower the bond strengths of Scotchbond, Clearfil New Bond, and Superbond C&B. The higher the dentin permeability, the lower the bond strength of Superbond C&B, but there was no simple relationship in the case of either Scotchbond or Clearfil New Bond. The bond strength of Superbond C&B was much higher than those of Scotchbond or Clearfil New Bond at any depth of dentin. Superbond C&B should be considered as both an enamel- and dentin-bonding agent.

Composite Resins↗