Biomedical subjects

Junji Tagami

Publications and source records attributed to Junji Tagami.

At least 91 records · Page 5Linked to original sources

PubMed2003

Micro-shear bond strengths of adhesive resins to coronal dentin versus the floor of the pulp chamber.

PURPOSE: To evaluate the micro-shear bond strengths to superficial coronal dentin and the floor of the pulp chamber using two dentin bonding systems and to compare the ultrastructure of the resin-dentin interface of the two regions. METHODS: 30 non-carious molars were used to obtain 2 mm thick slabs of coronal dentin and dentin at the pulp chamber. The specimens in each region were divided into three sub-groups to be bonded as follows; Clearfil SE Bond was used according to the manufacturer's instructions, Single Bond was applied to either wet dentin (Blot dry Group) or air-dried dentin (Dry Group) after phosphoric acid etching. A resin composite cylinder 0.5 mm high and 0.75 mm in diameter formed using a vinyl tube was bonded to the dentin. Specimens were stored at 37 degrees C for 24 hours in water and then stressed in shear at a crosshead speed of 1 mm/minute. The data were analyzed with one-way ANOVA and Fisher's PLSD test at the 5% level of significance. In addition, the ultrastructure of cross-sectioned dentin surfaces, the conditioned dentin surface and the resin dentin interfaces were observed by SEM. RESULTS: The bond strengths of Clearfil SE Bond and the Single Bond Blot dry group were approximately 40 MPa in coronal dentin and 30 MPa in the dentin at the floor of the pulp chamber respectively. However, the bond strengths of Single Bond were significantly lower in the Dry condition (MPa) (P < 0.05). SEM observations revealed the thickness of the hybrid layer created by Clearfil SE Bond in coronal dentin and at the floor of the pulp chamber were less than 1.0 microm thick. For Single Bond, a 3-4 microm hybrid layer was created in coronal dentin, while a thinner hybrid layer was observed in the floor of the pulp chamber. Morphological and structural variations in dentin may have influenced the bond strengths of the bonding systems to the floor of the pulp chamber.

Acid Etching, Dental↗

PubMed2003

Effect of light-curing method and irradiation time on marginal sealing and cavity wall adaptation of resin composite restorations.

PURPOSE: To evaluate the effect of irradiation time on two light-curing methods on the marginal sealing and cavity wall adaptation of resin-based composite restorations. METHODS: Cylindrical cavities, 1 mm deep and 3 mm in diameter (C-factor = 2.3) were prepared on flat superficial bovine dentin surfaces. The teeth were restored with Clearfil Photo Bond, Clearfil Liner Bond 2 or Super-Bond D-Liner adhesive systems followed by Photo Clearfil Bright resin-based composite. The resins were cured using a conventional method at an output of 600 mW/cm2 for 60 s, or 600 mW/cm2 for 30 s, or the slow-start curing method at an output of 270 mW/cm2 for 10 s + 5 s (interval) + 600 mW/cm2 for 50 s or 270 mW/cm2 for 10 s + 5 s (interval) + 600 mW/cm2 for 20 s. After thermocycling, a dye penetration test was carried out. The dye penetration length was calculated as a percentage of the total cavity wall length. RESULTS: Slow-start curing method; 270 mW/cm2 10 s + 5 s (interval) + 600 mW/cm2 for 50 s showed the best marginal sealing and cavity wall adaptation. A shorter irradiation time increased cavity wall adaptation when the conventional curing method was used. Super-Bond D-Liner showed good marginal sealing and resin composite adaptation to the cavity wall regardless of the light-curing method.

Animals↗

PubMed2003

The resin-coating technique. Effect of a single-step bonding system on dentin bond strengths.

PURPOSE: An experimental single-step bonding system, RZ-II, has been developed as a resin coating material for crown preparation. The purpose of this study was to compare the dentin microtensile bond strengths (MTBSs) of RZ-II in direct and indirect use. MATERIALS AND METHODS: Human molar dentin was used. The specimens were divided into three groups of n = 20 each. Group 1: RZ-II was applied to the dentin surface once or twice, and built up with a direct composite. Group 2: The dentin surface was provisionally covered and stored in water for 1 day. The provisional material was removed and an indirect composite was then bonded to the dentin surface. Group 3: RZ-II was applied to the dentin surface once or twice for "resin coating" before the placement and removal of provisional material. An indirect composite was then bonded to the coated dentin. After 1 day, MTBSs were measured at a crosshead speed of 1 mm/min. The data were analyzed using one-way ANOVA and Fisher's PLSD test (p < 0.05). The interface between the indirect composite and resin-coated dentin was also observed using a SEM. RESULTS: The MTBSs of RZ-II in Groups 1 and 3 were significantly higher than those of Group 2 (p < 0.05). The thickness of the resin-coating layer and the hybrid layer were 5 to 6 microm and less than 1 microm, respectively. CONCLUSION: The single-step bonding system, RZ-II, could be useful as a resin coating material for crown preparation.

Adhesiveness↗

PubMed2002

The effects of luting resin bond to dentin on the strength of dentin supported by indirect resin composite.

OBJECTIVES: The purpose of this study was to evaluate the effects of thickness and adhesion of three resin cements on the fracture resistance of indirect resin composite bonded to dentin. METHODS: A disk of resin composite used for indirect restorations was bonded to a disk of bovine dentin using three kinds of resin cements with various bonding procedures. The bonding procedures were planned into five groups according to the materials and methods, and subsequently subdivided into three groups according to the cement thickness (50, 150 and 500 microm) in each bonding procedure. The thickness of the resin cement and that of the resin composite disk was changed simultaneously while maintaining a total specimen thickness of 2 mm. The prepared specimens were then stored in water at 37 degrees C for 24h at which time they were trimmed to a size of 2 x 2 x 8 mm. The trimmed specimens were subjected to a three point bending test and the fracture load determined. The tensile bond strength of each bonding procedure was measured and the correlation to the fracture load evaluated. RESULTS: The fracture load was affected by the dentin bond strength. The effect of cement film thickness on the fracture load was negligible. SIGNIFICANCE: When an indirect restoration is adhered to the tooth substrate, the adhesion of the luting cement to the tooth substrate is very important for the fracture resistance of indirect resin composite.

Acid Etching, Dental↗

PubMed2002

Micro-shear bond strength of dual-cured resin cement to glass ceramics.

OBJECTIVES: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-cured resin cement to bond to glass ceramics designed for in indirect adhesive restoration. METHODS: A cast glass ceramic (Olympus Castable Ceramics) with a crystalline phase consisting of mica and beta-spondumene was selected as the substrate material. The glass surfaces, which were sandblasted, polished, or etched with phosphoric acid or hydrofluoric acid (HF), were bonded with a dual-cured resin cement (Panavia Fluoro Cement) using a dentin adhesive system (Clearfil SE Bond), both with and without a silane coupling agent. A micro-shear bond test was carried out to measure the bond strength of the resin cement to the glass surface. Each glass surface was bonded and tested using the shear test. In addition, surfaces with the bonding removed after the shear bond test, the adhesive interface between the glass and cement, and an etched glass surface without any bonding, were studied morphologically using scanning electron microscopy or field emission scanning electron microscopy. RESULTS: Usage of a silane coupling agent effectively raised the bond-strength values of resin cement (Fisher's PLSD, P<0.01). The effectiveness of using phosphoric acid etching to improve bonding was not clear (Fisher's PLSD, P>0.01). HF-etching for 30s seemed to over-etch the glass surface, resulting in adverse effects on bonding (Fisher's PLSD, P<0.01). SIGNIFICANCE: The micro-shear bond strength between Olympus Castable Ceramics and resin cement can be increased by the silane coupling agent used along with an acidic primer.

Acid Etching, Dental↗

PubMed2002

Effect of resin-coating technique on dentin tensile bond strengths over 3 years.

PURPOSE: The resin-coating technique has been developed to protect prepared dentin and underlying pulp tissue. The purpose of this study was to evaluate the resin-coated dentin bond durability over a period of 3 years of a resin cement and to compare it with two representative resin cements. MATERIALS AND METHODS: Ten bovine dentin specimens were tested for tensile bond strengths with each of the following three materials: CLAPEARL DC with a resin-coating technique (CDRC), Panavia 21 (PA21), and Super Bond C&B (SBCB) at 1 day, 6 months, 1 year, and 3 years. Mean bond strengths were compared statistically by two-way analysis of variance and Fisher's PLSD test (p < .05). The mode of failure was classified by scanning electron microscope observation and analyzed using the Mann-Whitney U-test. RESULTS: The 3-year bond strengths of all resin cements were significantly lower than those at the other experimental periods except for 1 year (p < .05). There was no significant difference in mean bond strength between CDRC and SBCB (p > .05). Regarding the fracture modes, in the case of CDRC, an increase in adhesive failure at the resin-dentin interface was observed as the time period lengthened. Statistical differences were observed between SBCB and the other materials at 1 year (p < .05) and between PA21 and the other materials at 3 years (p < .05). CLINICAL SIGNIFICANCE: The mean tensile bond strengths of the three resin cements to dentin decreased at different rates during the study; the rate at which the bond decreases is likely to affect the long-term durability of restorations.

Acid Etching, Dental↗

PubMed2002

The in vitro dentin bond strengths of two adhesive systems in class I cavities of human molars.

PURPOSE: The purpose of this study was to evaluate the in vitro dentin bond strengths of two dentin bonding systems in Class I cavities following fatigue load cycling (FLC) with thermal cycling (TC). MATERIALS AND METHODS: Class I cavities were prepared in 12 human molars and restored with either Clearfil SE Bond (SE) and Clearfil AP-X resin composite (AP-X) or Single Bond (SB)/AP-X according to the manufacturers' instructions. After water storage for 1 week, untreated controls and test samples were subjected to 50,000 FLC with TC from 5 degrees C to 55 degrees C for 625 cycles and stored in water for 1 week. Microtensile bond strength (MTBS) tests were measured on the floor of the cavities at a crosshead speed of 1 mm/min. Data were statistically analyzed using one- and two-way ANOVA and Fisher's PLSD test at a 5% level of significance. RESULTS: The MPa results were: SE 30.5+/-12.8 (control) and 23.2+/-10.8 (50,000 FLC); SB 5.1+/-9.2 (control) and 4.7+/-5.7 (50,000 FLC). Bond strengths were not statistically significantly affected by FLC (p > 0.05); however, they were influenced by the bonding system (p < 0.05). The MTBS of SE was significantly higher than that of SB (p < 0.05) under FLC and TC test conditions. Over half of the SB specimens debonded during sample preparation, showing blister-like structures, suggesting that an over-wet phenomenon occurred on the cavity floor. CONCLUSION: SE produced excellent dentin bonds that were much stronger than those produced by SB, which was shown to be a technique-sensitive bonding system.

Acid Etching, Dental↗

PubMed2002

Durability of the dual-cure resin cement/ceramic bond with different curing strategies.

PURPOSE: To evaluate the effects of different curing strategies on the durability of the dual-cure resin cement/ceramic bond. MATERIALS AND METHODS: Machinable ceramic blanks were cut into pairs of 3-mm-thick slices, which were then polished using wet 600-grit SiC paper. The slices were silanated using one of two ceramic priming systems: (1) Tokuso Ceramic Primer (TCP), and (2) K-etchant/Clearfil Liner Bond 2V Primer (LB2V)/Porcelain Bond Activator (PBA), and bonded with one of two dual-cure resin cements (Bistite II, Panavia F), to make four experimental groups. Each group was subjected to one of three curing strategies: (1) no light, (2) 20 s light exposure from one direction, and (3) 20 s light exposure from each of six directions. After 24 h water storage at 37 degrees C, 0.7-mm-thick slabs were produced by serially sectioning perpendicular to the bonded interface. Immediately thereafter, and after one and six weeks of water storage, two slabs were randomly selected and sliced into beams for the microtensile bond strength (microTBS) test. Data were evaluated using Kruskal-Wallis and Wilcoxon rank tests (p < 0.05), and failure modes determined using a laser-scanning confocal microscope. RESULTS: After priming with TCP, microTBS of Bistite II significantly increased over time when exposed to light, whereas the microTBS of the no-light group significantly decreased over time (p < 0.05). After priming with TCP, microTBS of Panavia F increased over time, and after 6 weeks water storage, there were no significant differences in microTBS between the no-light and light-exposed groups (p > 0.05). Increases in microTBS were associated with increases in the number of cohesive failures in resin cement. After phosphoric acid treatment, priming with LB2V/PBA, and light exposure, microTBS of Bistite II remained stable, whereas that of Panavia F significantly reduced over time (p < 0.05). The microTBS of no-light LB2V/PBA groups reduced significantly over time (p < 0.05). CONCLUSION: The durability of the dual-cure resin cement/ceramic bond depends upon the multicomponent ceramic primer and the amount of light received by the resin cement.

Acid Etching, Dental↗

PubMed2002

Long-term durability of the dual-cure resin cement/silicon oxide ceramic bond.

PURPOSE: To determine the effects of using a ceramic primer, ceramic bonding agent, or a combination of primer/bonding agent on the long-term durability of the dual-cure resin cement/silicon oxide ceramic bond. MATERIALS AND METHODS: Ceramic blocks (Vita Celay Blanks), A2M, were cut into 1-, 2-, and 3-mm-thick slices and polished using 600-grit SiC paper. Group 1 consisted of pairs of 1- and 3-mm-thick slices, and Group 2 of pairs of 2- and 3-mm-thick slices. Ceramic surfaces were treated with 40% phosphoric acid and silanated using one of three treatments: (1) Clearfil Liner Bond 2V Primer (2V Pr) and Porcelain Bond Activator (PBA), (2) Liner Bond 2V Primer/PBA and Liner Bond 2V Bond (2V Pr + Bd), and (3) Clearfil Photo Bond/PBA (P Bd). They were then bonded with a dual-cure resin cement (Panavia F) and light-cured for 20 s from each of six directions. After 24 h water storage at 37 degrees C, 0.7-mm-thick slabs were serially sectioned. Immediately thereafter, after one and six weeks, and after one year of water storage, two slabs were randomly selected from each subgroup and sliced into beams for the microtensile bond strength (microTBS) test. Data were evaluated with three-way ANOVA and Fisher's PLSD test (p < 0.05) and failure modes determined using a laser-scanning confocal microscope. RESULTS: After 1 day, there were no significant differences between 2V Pr, 2V Pr + Bd, and P Bd (p > 0.05), whereas after one year, significant differences were found (p < 0.05). For Group 1, the micriTBS of P Bd after one year of water storage was similar to that after one day. In both groups, microTBS of 2V Pr and 2V Pr + Bd significantly decreased over time (p < 0.05), which was accompanied by an increase in the percentage of complete adhesive failures. CONCLUSION: The chemical composition of the multicomponent ceramic primer/bonding agent significantly affects the long-term durability of the dual-cure resin cement/silicon oxide ceramic bond. The presence of water in a ceramic primer has a significant detrimental effect on resin-ceramic bond durability. In addition, the thickness of the ceramic restoration influences dual-cure resin cement/ceramic bond durability.

Analysis of Variance↗

PubMed2002

Histomorphometric analysis of dentinal bridge formation and pulpal inflammation.

OBJECTIVE: The purpose of this study was to evaluate pulpal responses to the use of four resin composite materials as direct pulp capping agents. The importance and effects of individual pulp capping variables are not well understood; consequently histomorphometric analysis was used to analyze these variables. METHOD AND MATERIALS: Two hundred fifty standardized pulp-exposed cavities were prepared in nonhuman primate teeth. Exposed pulps were capped with calcium hydroxide and multistep and self-etching primer resin composites. Teeth were collected from 3 to 60 days to observe pulpal reactions. Following perfusion fixation, tissues were demineralized, sectioned, stained, and histomorphometrically measured. Bridge area, diameter of pulpal exposure, and cavity floor width were measured. Tunnel defects, operative debris, and pulpal inflammation were graded according to defined criteria. RESULTS: The variables correlated to dentinal bridge area were, in decreasing order of significance, time elapsed since exposure, diameter of pulpal exposure, pulp capping material, and tunnel defects. The variables correlated to pulpal inflammation were the type and curing of pulp capping material. Other variables were not statistically significant. CONCLUSION: Pulp capping with resin composite materials provided acceptable pulpal inflammatory and dentinal bridge repair responses, comparable with those of calcium hydroxide. Although resin composites are promising as direct pulp capping agents, further investigations are required to optimize their application protocols to reduce the penetration of potentially cytotoxic monomers into pulpal tissue.

Acid Etching, Dental↗

PubMed2002

Enhanced bond strengths of compomers using two dentin bonding systems.

PURPOSE: To measure bond strengths of three commercial compomers using recent dentin bonding systems, and to observe the micromorphology of the cross-sectional interface of the bonded specimens. MATERIALS AND METHODS: One hundred and ten bovine teeth stored frozen were used. The dentin surfaces were ground flat with #600-grit silicon carbide paper, and divided into three groups for bonding: original bonding system group (Xeno Bond/Xeno, Prime&Bond 2.1/Dyract AP, and F2000 Primer/Adhesive/F2000 compomer), Clearfil Liner Bond 2V group (LB 2V/Xeno, LB2V/Dyract AP, LB2V/F2000 compomer, LB2V/AP-X), and Single Bond group (SB/Xeno, SB/Dyract AP, F2000 compomer, SB/Z100). After the bonding procedures had been performed, the bonded assemblies were stored in water for 24 hours at 37 degrees C. Then, tensile bond strengths were measured using a universal testing machine at a crosshead speed of 2 mm/minute. All data were statistically analyzed using one-way ANOVA and Fisher's PLSD at 95% of confidence. Specimens for SEM observations were bonded in the same manner as for the tensile bond test, cut in half, and embedded in epoxy resin. These were then polished to high gloss, gold sputter-coated, and observed with the SEM. RESULTS: Compomers bonded to dentin with recent dentin bonding systems showed significantly higher bond strengths than those with the original bonding systems (P< 0.05). Tensile bond strength of Clearfil Liner Bond 2V was also significantly higher than that of Single Bond (P< 0.05). SEM observations showed good interaction between the compomers, adhesive systems, and dentin with any restorative material used. For Xeno Bond/Xeno, Prime & Bond 2.1/Dyract AP, and Primer/Adhesive/F2000 compomer, the thicknesses of the hybrid layer were approximately 0.8-1.1 microm, 0.3-0.5 microm, and 0.7-1.5 microm respectively. On the other hand, the hybrid layer produced by LB2V was approximately 0.5 to 1.0 microm, whereas for SB was approximately 3.1 to 4.1 microm thick. The thickness of the hybrid layers created in each bonded sample depended on the adhesive material used.

Analysis of Variance↗

PubMed2002

Micro-shear bond strength of resin-bonding systems to cervical enamel.

PURPOSE: To evaluate the micro-shear bond strength of current adhesive systems to cervical and mid-coronal enamel. MATERIALS AND METHODS: Two commercially available resin adhesives were investigated; a self-etching primer system (Clearfil SE Bond) and a one-bottle adhesive system (Single Bond) intended for use with the total-etch wet-bonding technique were employed. Two regions of enamel, cervical and mid-coronal regions, were chosen from the buccal surface of extracted molars and were then bonded with each adhesive system and submitted to the micro-shear bond test. In addition, the conditioned enamel surfaces without any bond and the enamel-resin adhesive interfaces were studied morphologically using scanning electron microscopy (SEM). RESULTS: No significant differences were found between the adhesive systems used (P > 0.05). However, for both bonding systems, cervical enamel showed significantly lower bonding than mid-coronal enamel (P < 0.05). The relatively lower bond strengths obtained from cervical enamel probably resulted from its aprismatic structure, which appears to be more resistant to dissolving in acids than prismatic mid-coronal enamel.

Analysis of Variance↗

PubMed2002

Shear bond strengths to coronal and pulp chamber floor dentin.

PURPOSE: To evaluate the bond strengths of two different types of resin bonding systems to coronal dentin and dentin of the pulp chamber floor. MATERIALS AND METHODS: 20 extracted human molars were sectioned into three regions; superficial coronal dentin, deep coronal dentin and floor of pulp chamber dentin. The dentin surface of each region was bonded with Single Bond or Clearfil Liner Bond 2V. A core build-up light-cured resin composite, Clearfil Photocore, was placed and light-cured for 40 seconds. After storage in 37 degrees C water for 24 hours, shear bond strengths were measured using a single plane shear test assembly at a crosshead speed of 2.0 mm/minute. Morphological changes of the conditioned dentin and hybrid layer formation were observed by SEM. RESULTS: For Single Bond, the bond strengths to superficial dentin were within anticipated bounds (23 MPa), whereas the bond strengths to deep dentin (15 MPa) and floor of pulp chamber dentin (13 MPa) were significantly lower (P < 0.05). For Clearfil Liner Bond 2V, higher bond strengths (approximately 30 MPa) were obtained for each region. The data were analyzed by one- and two-way ANOVA, and Fisher's PLSD (P < 0.05). The appearance of the conditioned dentin varied according to dentin region and conditioner. For Single Bond, thick hybrid layers (3-4 microm) were observed, while thin hybrid layers (less than 0.5 microm) were observed in Clearfil Liner Bond 2V for all regions.

Analysis of Variance↗

PubMedDate not supplied

Morphological and mechanical characterization of the acid-base resistant zone at the adhesive-dentin interface of intact and caries-affected dentin.

This study examined the ultrastructure of both intact and caries affected dentin-adhesive interface after artificial secondary caries formation, using scanning electron microscopy and nanoindentation testing. Half of the prepared specimens were bonded with Clearfil SE Bond (Kuraray Medical, Japan) and a resin composite (Metafil Flo, Sun Medical, Japan) for the nanoindentation test. The other specimens were stored in a buffered demineralizing solution for 90 minutes, then observed using SEM. An acid-base resistant zone (ABRZ) was observed beneath the hybrid layer, distinguished by argon-ion etching. The ABRZ of caries-affected dentin was thicker than that of normal dentin, while its nanohardess was lower than normal dentin (p<0.05). It is suggested that the monomer of Clearfil SE Bond penetrated deeper than previously reported, creating a so-called "hybrid layer." However, its physical properties depended on the condition of the dentin.

Acids↗

PubMedDate not supplied

Pulpal response to a fluoride-releasing all-in-one resin bonding system.

Pulp tissue reactions to a fluoride-releasing all-in-one resin bonding system (Reactmer Bond and Reactmer Paste) in non-exposed monkey teeth were histopathologically evaluated at three, 30, and 90 days after restoration. No serious inflammatory reactions of the pulp, such as necrosis or abscess formation, were observed. At 90 days in the Reactmer group, odontoblastic change and inflammatory cell infiltration were not observed, and slight irritation dentin formation was formed. The pulpal response of the Reactmer group was minimally different from that of the control group. Consequently, the Reactmer system was determined as being biologically compatible with vital pulps.

Abscess↗

PubMedDate not supplied

Long-term durability of resin dentin interface: nanoleakage vs. microtensile bond strength.

This study tested the hypothesis that long-term durability of resin bonds to dentin is directly related to the nanoleakage of dentin bonding systems. Extracted human third molars were ground flat with 600-grit SiC paper under running water to expose middle dentin. Clearfil Liner Bond 2V (LB2V) or Fluoro Bond (FB) was applied to dentin surfaces according to the manufacturer's instructions. 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 vertically sectioned into approximately 0.7 mm thick slabs and trimmed for microtensile bond test. All slabs were immersed in individual bottles of water at 37 degrees C, which was changed every day. Specimens were incubated for one day, and three, six, and nine months, and at the specified time period, they were randomly divided to two subgroups: 50% AgNO3 and the control. In the 50% AgNO3 subgroup, the slabs were 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 debonding. Then, all specimens were subjected to microtensile bond testing. The debonded specimens of the AgNO3 subgroup had micrographs subjected to image analysis by NIH Image PC (Scion, Fredrick, MD, USA), and the area of silver penetration was quantitated. The bond strength data and 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 penetration area at each time period. For both adhesive systems, the bond strengths gradually decreased over time, although there were no statistically significant differences in the FB bond strength among the four time periods tested (p>0.05). Silver penetration in specimens bonded with LB2V and FB gradually increased over time. Regression analysis showed a higher correlation between bond strength and silver penetration at 9 months for specimens bonded with LB2V (R2=0.844) than at shorter time periods. The authors speculate that hydrolytic degradation within the hybrid layer gradually increased due to water penetration through nanoleakage channels, resulting in lower bond strengths and interfacial failure after as little as nine months.

Analysis of Variance↗

PubMedDate not supplied

Bond strength of two adhesive systems to primary and permanent enamel.

The bonding performance of current adhesive systems to primary enamel has not been thoroughly researched. This study compared the micro-shear bond strength of two adhesive systems to primary and permanent tooth enamel. Two commercially available resin adhesives, a self-etching primer system (Clearfil SE Bond) and a single-bottle adhesive system (Single Bond) used with a total-etch wet bonding technique were tested. A micro-shear bond test was used to examine the adhesive systems on mid-coronal buccal enamel of extracted primary or permanent teeth. In addition, etched enamel surfaces and etched-bonded enamel interfaces were examined using scanning electron microscopy (SEM). No statistically significant differences of shear bond strength values were found between the primary and permanent enamel or the adhesive systems used (p>0.01). The SEM observations showed that both adhesive systems etched the primary enamel deeper than the permanent enamel, suggesting that the action of acid etch seemed to be more intense on primary enamel than on permanent enamel. Bonding of the adhesive systems to primary enamel was almost identical to permanent enamel.

Acid Etching, Dental↗

PubMedDate not supplied

Effect of residual water on dentin bond strength and hybridization of a one-bottle adhesive system.

This research investigated the effects of wet and dry conditions of phosphoric acid etched dentin on resin bonding and determined the optimum moisture condition for resin bonding using an ethanol-based one-bottle adhesive system. Bovine dentin surfaces were etched with 35% phosphoric acid and rinsed with water. Under four wet and dry conditions (overwet, blot dry, one-second dry and desiccated), resin composite was bonded using Single Bond. Tensile bond strength was measured and the results analyzed by one-way ANOVA and Fisher's PLSD test at the 5% level. The resin-dentin interfaces of bonded specimens were observed with SEM. The bond strength of overwet, blot dry, one-second dry and desiccated groups were 5.2 MPa, 12.6 MPa, 11.9 MPa and 4.4 Mpa, respectively. The blot dry group and one-second dry groups revealed significantly higher bond strengths than the desiccated and overwet groups (p < 0.05). The formation of hybrid layers approximately 5 microm thick (overwet and blot dry), 2 microm (one-second dry) and 3 microm (desiccated) were observed. The coefficient of variation in the blot dry group was very high, even though a higher mean was observed. In the one-second dry group, the moisture content of the collagen network was possibly too low, such that hybrid layer formation was not as good even though the bond strength was high.

Acid Etching, Dental↗