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Biomedical subjects

J Tagami

Publications and source records attributed to J Tagami.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Effect of various pretreatments for dentin bonding on dentin permeability].

Pretreatment of the dentinal surface with acidic solution is now considered to be necessary to obtain strong bonding between dentin and resin materials. Effects of various surface treatments for dentin bonding on dentinal smear removal have been reported by SEM observation. In this study, changes of dentin permeability after the surface treatments were measured using Pashley's technique. Forty-second treatments with either phosphoric acid gel, aqueous phosphoric acid, 10-3 solution or aqueous 10-20 Ca solution (10% citric acid containing 20% CaCl2) produced greater increases in dentin permeability compared with the treatments using either 10-20 Ca gel, Tenure Conditioner, Scotchprep or Gluma 2 for 40 seconds. Treatments with primers including adhesive monomers such as Scotchprep and Mirage Conditioner also increased the dentin permeability by removal of the smear layers and smear plugs. Application of a bonding agent (Clearfil Photobond) for 1 minute did not remove the smear plugs and the dentin permeability remained the same as before the treatment. The changes in dentin permeability were not predictable by SEM observation in some cases.

Acid Etching, Dental↗
PubMed1989

The permeability of dentine from bovine incisors in vitro.

The permeability of coronal dentine was investigated by measuring the hydraulic conductance of dentine discs. Reductions in dentine thickness from the enamel side of disc resulted in a greater increase in permeability than reductions from the pulpal side. Scanning electron microscopy revealed fewer dentinal tubules with smaller diameters in superficial dentine than in deep dentine. The permeability of coronal incisor bovine dentine is six to eight times less than that of unerupted coronal human third molar dentine but similar to that of human root dentine.

Animals↗
PubMedDate not supplied

Hierarchy of variables correlated to odontoblast-like cell numbers following pulp capping.

OBJECTIVES: Following tooth pulp exposure, pulpal repair is accomplished by dentine bridge secretion by odontoblast-like cells. However, little information is available about the hierarchy of variables, which influence odontoblast-like cell numbers. The purpose of this study was to examine correlations between pulp capping events and odontoblast-like cell numbers. METHODS: Two hundred and fifty standardised pulp exposed cavities were prepared in non-human primate teeth according to ISO usage guidelines. Exposed pulps were capped with Calcium hydroxide [Ca(OH)(2)], and multi-step and self-etching primer composite resins. Teeth were collected from 3 to 60-days to observe pulp reactions. Statistical analysis was evaluated using analysis of variance. RESULTS: The hierarchy of variables correlated to odontoblast-like cells were the dentine bridge area (P = 0.0001), time since pulp exposure (P = 0.0001), odontoblast numbers opposite the exposure site (P = 0.0002), and pulp capping materials (P = 0.0313). Other pulp capping variables were found to be less likely to be correlated with odontoblast-like cell numbers. CONCLUSIONS: The area of dentine bridge formation is directly related to the numbers of odontoblast-like cells, cell activity is time dependent, and the cell numbers are much lower than original odontoblast cells. The time-lag between the appearance of odontoblast-like cells at the site of pulp exposure, and the limited numbers of these cells, explain why pulpal repair is difficult to achieve successfully following pulp exposure.

Animals↗
PubMedDate not supplied

Adhesion of resin-modified glass ionomer cements using resin bonding systems.

OBJECTIVES: To compare the in vitro shear bond strength of two commercially available resin-modified glass ionomer cements (RmGIC) to bovine dentine, with and without the use of adhesive bonding systems. METHODS: Ninety-six flat bovine dentine surfaces were divided into eight groups for bonding procedures. Fuji II LC and Vitremer were bonded to dentine that had been treated with and without Clearfil Photo Bond, Clearfil Liner Bond, or Clearfil Liner Bond II. The control group consisted of specimens that were treated as recommended by the manufacturer of each resin-modified glass ionomer cement. The bonded assemblies were stored in tap water for 24 h at 37 degrees C, and shear bond strengths measured using a universal-testing machine at a crosshead speed of 1 mm/min. RESULTS: For the control group, shear bond strength of Fuji II LC was significantly greater than Vitremer (P < 0.005). However, when any of the resin bonding systems was applied, no statistical difference between Fuji II LC and Vitremer was determined (P > 0.05). The Clearfil PhotoBond and Liner Bond groups showed similar bond strengths (P > 0.05), but were significantly less than Liner Bond II (P < 0.001). CONCLUSIONS: A recent bonding system combined with the RmGICs exhibited the greatest shear bond strength to dentine, irrespective of chemical differences that may exist between the two RmGICs.

Adhesives↗
PubMedDate not supplied

In vitro secondary caries inhibition around fluoride releasing materials.

Objectives of the study were to compare the capacity of fluoride releasing materials to inhibit in vitro caries formation and to measure the width and height of the inhibition zones. Box-shaped cavities were prepared on bovine root dentine and restored with Fuji II, Fuji II LC. Vitremer, or Clearfil Liner Bond II system with a fluoride releasing composite. After immersion in a buffered demineralizing solution of 50 mmol/L acetic acid adjusted to pH 4.5 for 3 days, longitudinal sections were cut and imbibed in quinoline for analysis under a polarized light microscope (PLM). The contours of the lesions and inhibition zones were traced and their depth, width and height calculated. The data were analyzed by one-way ANOVA and Fisher's PLSD test at 95% level of confidence. The polarized light microscopy results showed a distinct inhibition zone adjacent to both conventional and resin-modified glass ionomer cements; however, it was not observed around the adhesive resin system. The width and height of this inhibition zone were significantly greater for Fuji II than for Fuji II LC and Vitremer. An inhibition zone was not observed adjacent to the adhesive resin system with fluoride releasing composite. The resin-modified glass ionomer cements produced less protection against in vitro secondary caries formation than the conventional glass ionomer cement. The recent bonding system that releases fluoride failed to produce an inhibition zone along the cavity wall adjacent to the restoration.

Acetates↗
PubMedDate not supplied

Effect of dentin primer application on regional bond strength to cervical wedge-shaped cavity walls.

The purpose of this study was to examine the effect of multiple applications of self-etching primer on regional tensile bond strength (microTBS) to artificial wedge-shaped cavities (i.e., occlusal vs gingival wall). Eighteen extracted noncarious human molars were used to measure microTBS, and four additional teeth were used for scanning electron microscopy (SEM) of the interface. Wedge-shaped defects were prepared in the buccal cervical dentin. The teeth were mounted on their distal surface, simulating the supine position of the teeth during dental treatment. The teeth were divided into two groups according to the bonding systems [Clearfil Liner Bond II (LB) or Imperva Fluoro Bond (FB)], and again divided into two subgroups for bonding. One group (Group S) was treated once with the primer according to the manufacturer's instructions. For the other group (Group M), the primer was applied several times for the period recommended by the manufacturer. The adhesive bonding resins were then applied to the cavity walls, and restored with a low-viscosity resin composite (Protect Liner F), and stored in 37 degrees C water for 24 hours. The resin-bonded teeth were serially sliced parallel to the long axis of the tooth. The adhesive interface of each slice was trimmed alternately at the occlusal or gingival wall, and a microtensile testing method was used to compare resin bond strength to each wall. With both adhesive systems and primer application methods, tensile bond strength to the gingival wall was significantly lower than to the occlusal wall (P < 0.05). Tensile bond strength of LB to each cavity wall of a wedge-shaped defect increased significantly by multiple primer application (P < 0.05); however, bond strengths of FB were not significantly different after multiple primer applications.

Analysis of Variance↗
PubMedDate not supplied

Influence of the direction of tubules on bond strength to dentin.

This study investigated the influence of the direction of dentinal tubules on resin-dentin tensile bond strength (mu TBS) using four commercially available bonding systems and observed the resin-dentin interfaces with an SEM. The dentin bonding systems used in this study were Clearfil Liner Bond II (LB, Kuraray), Imperva Fluoro Bond (FB, Shofu), Single Bond (SB, 3M) and One-Step (OS, BISCO). Thirty-six extracted caries-free human molars were used for micro tensile bond testing and eight additional teeth were used for scanning electron microscopy (SEM). The teeth were divided into two groups according to the direction of the dentinal tubules at the resin-dentin interface: a perpendicular group, in which the occlusal enamel was removed perpendicular to the long axis of the tooth, and a parallel group, in which the mesial half of the tooth was removed parallel to the long axis of the tooth, and the coronal dentin surface was used for bonding. After the flat dentin surfaces were polished with #600 silicon carbide paper, each surface was treated with one of the four adhesive systems according to the manufacturer's recommendation, then covered with resin composite (Clearfil AP-X, Kuraray) to provide sufficient bulk for micro-tensile bond testing. After 24 hours in 37 degrees C water, the resin-bonded teeth were serially sliced perpendicular to the adhesive surface, the adhesive interface trimmed to a cross sectional area of 1 mm2 and subjected to tensile forces at a crosshead speed of 1 mm/min. Statistical analysis of the tensile bond strengths were performed using two-way ANOVA and Fisher's PLSD test at 95% level of confidence. The tensile bond strength of the group with tubules parallel to the bonded interface was higher than that of tubules cut perpendicularly. This tendency reached statistical significance using SB and OS.

Analysis of Variance↗
PubMedDate not supplied

The effect of additional enamel etching and a flowable composite to the interfacial integrity of Class II adhesive composite restorations.

This in vitro study evaluated the interfacial integrity of Class II resin composite restorations. The influence of a flowable composite and additional enamel etching was also evaluated. Deep, saucer-shaped Class II cavities were prepared in the mesial and distal proximal surfaces of 25 extracted human molars and assigned to five treatment groups. The gingival margins were extended to approximately 1 mm above the CEJ in 40 cavities and below the CEJ in 10 cavities. The prepared cavities were then restored with a self-etching primer system (Clearfil Liner Bond II) and a hybrid resin composite (Clearfil AP-X), with and without a flowable composite (Protect Liner F) and additional enamel etching with 37% phosphoric acid gel (K-etchant). After finishing, polishing and thermocycling (4 and 60 degrees C, x300), the samples were longitudinally sectioned through the restorations and resin-tooth interfaces were observed directly under a laser scanning microscope. Statistical analysis indicated that the use of a flowable composite produced significantly more (p = 0.04) gap-free resin-dentin interfaces than teeth restored without the flowable composite. However, both flowable composite and enamel etching could not prevent gap formation at enamel-resin interfaces and crack formation on enamel walls.

Acid Etching, Dental↗
PubMedDate not supplied

Relationship between adhesive thickness and microtensile bond strength.

This study evaluated the effect of the thickness of the adhesive resin layer of two commercially available resin bonding systems on bond strengths (Single Bond and Liner Bond 2V). The adhesive of Single Bond contains ethanol and water as solvents and is applied using the moist-bonding technique. The adhesive of Liner Bond 2V contains no solvents and is applied after a self-etching primer treatment. Forty-six caries-free molars were ground flat to expose the dentin surface and polished with #800-grit silicon carbide paper under running water. A vinyl tape punched with a 6 mm diameter hole was then placed on the dentin surface to demarcate the area for bonding. The thickness of the adhesive resin layer was varied by stacking an increasing numbers of vinyl tapes together. The teeth were randomly divided into two groups and treated with either Clearfil Liner Bond 2V or Single Bond. They were further divided into subgroups according to the number of tapes placed on the dentin surface. After the bonding procedures the teeth were incrementally restored with Clearfil AP-X resin composite, building a 5 mm high crown to produce sufficient bulk for the microtensile bond test and stored in tap water at 37 degrees C for 24 hours. The teeth were then sectioned along their long axis into 0.7 mm thick slabs and trimmed for the microtensile bond test using a super-fine diamond bur. The thickness of the adhesive resin layer was then measured with a light microscope and the slabs tested in tension at a crosshead speed of 1 mm/minute. The results were subjected to statistical analysis by a one-way analysis of variance and linear regressions with 95% confidence intervals. The thickness of the Clearfil Liner Bond 2V adhesive layer ranged from 5 mm-1500 mm, and for Single Bond, it varied from < 7.5 mm-430 mm. For Clearfil Liner Bond 2V, bond strengths increased significantly as the thickness of bonding layer increased (p < 0.05). However, the bond strengths of the Single Bond decreased significantly with increased thickness of the bonding layer (p < 0.05).

Acid Etching, Dental↗
PubMedDate not supplied

Bond strengths of single-bottle dentin adhesives to caries-affected dentin.

There is concern that some acidic conditioners may not be strong enough to adequately etch sclerotic or caries-affected dentin. The hypothesis that was tested was that there were no significant differences in the bond strengths of single-bottle bonding systems to normal or caries-affected dentin, regardless of the strength of the phosphoric-acid conditioner. Extracted teeth with coronal caries extending into mid-dentin were prepared by grinding the occlusal surface flat. This left a central region of caries-affected dentin surrounded by normal dentin. The One-Step bonding system was used to bond dentin following etching with 10 or 32% phosphoric acid. The Single Bond system was used after etching dentin with 10 or 35% phosphoric acid. After 24 hours in water, serial vertical sections were made through the bonded teeth to create slabs 0.7 mm thick. Each tooth yielded four to five slabs, some of which included normal dentin, while others included caries-affected dentin. Each slab was trimmed into an hourglass configuration to limit the test area to normal or caries-affected dentin. The results obtained with One-Step following etching with 10% phosphoric acid showed lower (P < 0.05) tensile bond strengths to caries-affected dentin compared to normal dentin (36.9 +/- 8.0 MPa vs 47.7 +/- 6.5 MPa, respectively). This difference disappeared when using 32% phosphoric acid (49.7 +/- 6.1 MPa vs 45.0 +/- 7.2 MPa, respectively). Bonds made to caries-affected dentin with Single Bond were always lower than bonds to normal dentin regardless of the strength of the phosphoric acid. Scanning electron microscopy of polished cross sections sequentially challenged with acid and NaOCl revealed loss of the middle of the hybrid layers created by either bonding system in caries-affected dentin etched with 10% phosphoric acid. It is clear that 32-35% phosphoric acid is required to adequately etch caries-affected dentin in order to produce high bond strengths and well-infiltrated demineralized dentin.

Acid Etching, Dental↗
PubMedDate not supplied

Short-term dentin bridging of mechanically-exposed pulps capped with adhesive resin systems.

Dentin bridging of 150 mechanically exposed monkey pulps to two adhesive resins [BondWell LC (BW); Clearfil Liner Bond II (LB)] and a calcium hydroxide cement [Dycal (DY)] were histopathologically evaluated at 3, 7, 14, 30, and 60 days after operation (n = 10). The dentin bridge structure was three-dimensionally reconstructed from serial sections using a computer-aided reconstruction system. At three and seven days, in all pulps, no necrotic tissue and slight inflammatory cell infiltration was observed just below the exposure site. At 14 days, spindle-shaped fibroblast cells could be detected at the wound surface. All dentin chips showed reparative dentin deposition along the periphery of the wound surface. From this stage, the formation of secondary dentin from the pulpal wall at the periphery of the exposed area was recognized in all pulps. At 30 days, initial signs of dentin bridging were observed at the wound surface with a well-organized layer of odontoblastoid cells. The exposed area became occluded with a dentin bridge as the observation period increased. Group DY showed significantly higher incidence of dentin bridging than other groups at 30 days (p < 0.05). However, no significant difference of dentin bridge formation was found between Group DY and Groups BW and LB at 60 days. Bacterial penetration along the cavity walls and pulp tissue could not be detected in all groups. Histopathological observations and three-dimensional image analysis suggested that dentin bridge formation may occur following three patterns: (1) formed from the periphery of the residual dentin chip at the wound surface within 14 days, (2) formed within 14 days from the periphery of the cavity floor and with formation of reparative dentin by stimulation during the cavity preparation, and (3) formed from the wound surface within 30 days after exposure.

Animals↗
PubMedDate not supplied

Effects of different burs on dentin bond strengths of self-etching primer bonding systems.

This study evaluated the effects of cutting dentin with different types of burs on tensile bond strength using three self-etching primer bonding systems (Clearfil Liner Bond 2 [LB2], Clearfil Liner Bond 2V [2V] and Clearfil SE BOND [SE], Kuraray, Co, Ltd, Osaka, Japan). Thirty-six intact extracted human third molars were ground flat to expose occlusal dentin, followed by polishing the dentin surfaces with #600 SiC paper. The teeth were divided into four groups according to bur type and grit: fine cut fissure steel bur (SB600), cross cut fissure steel bur (SB703), regular grit diamond bur (DB). Controls were abraded with #600 grit SiC paper (AP#600). The dentin surfaces of the SB600, SB703 and DB groups were cut under copious air-water spray with the respective burs mounted in a dental handpiece. The teeth were treated with one of three adhesive systems, then composite buildups were created with Clearfil AP-X (Kuraray Co, Ltd, Osaka, Japan). After soaking in water at 37 degrees C for 24 hours, serial vertical sections (0.7 mm thick, 7-8 slices per one tooth) were made, trimmed to form an hour-glass shape with a 1.0 mm2 cross-section and tensile bond strengths were determined at a cross-head speed of 1 mm/min. Statistical analysis was made using one and two-way ANOVA and Fisher's PLSD test (p<0.05). Eight additional molars were prepared. Burs or abrasive paper were used for SEM observations of the dentin surfaces of each group before and after treatment with the self-etching primers. All adhesive systems yielded the same ranking of bond strengths to the surfaces prepared with different abrasives: from highest to lowest, AP#600 > SB600 > SB703 > DB. This ranking reached statistical significance using Clearfil Liner Bond 2V (p<0.05). Therefore, when cutting dentin, selecting the adequate bur type is important for improved bonding of adhesive systems using self-etching primer to dentin.

Acid Etching, Dental↗
PubMedDate not supplied

Relationship between nanoleakage and long-term durability of dentin bonds.

This study tested the hypothesis that long-term durability of resin bonds to dentin would directly relate to the nanoleakage of dentin bonding systems. Twenty extracted third molars were ground flat with #600 grit SIC paper under running water to expose middle dentin. One-Step or Single Bond was applied to the dentin surface according to the manufacturer's instruction. A crown was built-up with Clearfil AP-X resin composite and the specimens were stored in water for 24 hours at 37 degrees C. The bonded assemblies were cut mesio-distally perpendicular to the interface in approximately 0.7 mm thick slabs and trimmed for microtensile bond strength testing. All slabs were immersed in individual bottles containing 37 degrees C water that was changed daily. Specimens were randomly assigned to four groups (one day, three, six and nine months), and at the specified time period, the specimens to be tested were randomly divided into two subgroups for testing: 50% AgNO3 and the control. In the 50% AgNO3 subgroup, the slabs were coated with fingernail varnish except for approximately 0.5 mm around the bonded interface and immersed for one hour in 50% AgNO3, followed by exposure in a photo developing solution for 12 hours just prior to debonding. The specimens in the control subgroup were soaked in water until they were debonded. Then, all specimens were subjected to microtensile bond testing. Micrographs of the fractured surfaces of the debonded specimens in the AgNO3 subgroup were taken using light microscopy. They were then subjected to image analysis by NIH Image PC (Scion, Fredrick, MD, USA), and the area of silver penetration was quantitated. The fractured surface was further analyzed under the SEM. Bond strength data and the silver penetration areas were subjected to two and three-way ANOVA and Fisher's PLSD test at the 95% level of confidence. Regression analysis was used to test the relationship between bond strengths and the silver penetra tion area at each time period. The tensile bond strength of both materials gradually decreased over time. Specimens bonded with One-Step showed less silver nanoleakage at one day compared to three, six and nine months (p<0.05), but there were no significant differences between the nanoleakage measured at three, six and nine months. In contrast, for specimens bonded with Single Bond, there were no statistically significant differences in the silver nanoleakage among the four time periods tested (p>0.05). No correlation was observed between bond strength and nanoleakage for either bonding system. Nanoleakage occurred in both adhesive systems, and bond strengths gradually decreased over time. However, there was no correlation between bond strength and nanoleakage for either adhesive system in this study.

Analysis of Variance↗