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PubMed2006

Effect of thermal cycling on bond strengths of single-step self-etch adhesives to bovine dentin.

The purpose of this study was to clarify the effect of thermal cycling on dentin bond strengths of single-step self-etch adhesives. Five commercially available single-step self-etch systems were used. The adhesives were applied to the dentin surfaces of bovine incisors, and then light-irradiated. Resin composites were condensed into a mold and light-irradiated. Bonded specimens were divided into two groups and stored in water at 37 degrees C for 24 h without thermal cycling, or in water at 37 degrees C for 24 h followed by 10,000 thermal cycles between 5 degrees C and 60 degrees C. Ten samples per group were tested for shear strength at a crosshead speed of 1.0 mm/min. The data were analyzed by Student's t test and Tukey HSD test at a probability level of 0.05. After 24 h of storage in water, the mean dentin bond strengths ranged from 9.3 MPa to 14.0 MPa. After 10,000 thermal cycles, the mean bond strengths remained unchanged. Failure after the test was commonly due to adhesive breakdown associated with partial cohesive failure of the resin. The present results suggest that the benefit of using single-step self-etch systems, in terms of simplifying the clinical procedure, might be acceptable even after thermal stresses.

Acid Etching, Dental↗
PubMedDate not supplied

Bond strengths of a 1-step self-etching system to caries-affected and normal dentin.

This study was designed to evaluate the bond strengths of a 1-step self-etching system and a 2-step "etch and rinse" adhesive system to caries-affected dentin and normal dentin. In addition, the micromorphology of the adhesive interfaces was analyzed using scanning electron microscopy (SEM). Extracted human molars with occlusal caries that had been stored frozen were ground in order to expose the caries-affected dentin and surrounding normal dentin. The teeth were then bonded using either Adper Prompt L-Pop or Single Bond (3M ESPE) and restored with Filtek Z250 (3MESPE). After storage in water for 24 hours at 37 degrees C, the teeth were sectioned, prepared for microtensile bond strength test and tested in tension at a crosshead speed of 1-mm/minute. After debonding of the interfaces, microhardness of the dentin underlying the interface of all specimens was measured. The thickness of the hybrid layers was observed under SEM. The results of this study indicate that the bond strength of Adper Prompt L-Pop adhesive was significantly higher to normal dentin than to caries-affected dentin (p<0.05) and that the bond strength of Single Bond to both normal and caries-affected dentin was not significantly different (p>0.05). Additionally, the thickness of the hybrid layers produced by both adhesive systems was thicker for caries-affected dentin.

Acid Etching, Dental↗
PubMedDate not supplied

Morphological evaluation of 2- and 1-step self-etching system interfaces with dentin.

This in vitro study evaluated the resin-dentin interface formed by two 2-step and two 1-step self-etching adhesive systems under SEM. Class V cavities (4 x 2.5 x 1.5 mm) were prepared on the buccal surfaces of 25 extracted intact human third molars using a carbide bur in a high-speed handpiece. Four self-etching systems with corresponding resins were used: two 2-step systems, AdheSE (Ivoclar Vivadent) and Contax (DMG Hamburg), one 1-step/2 components system Futurabond NR (Voco) and a 1-step/1 component adhesive G-Bond (GC Corp). An etch and rinse system, PQ Clear (Ultradent), was used as a control. The teeth were thermocycled (500 cycles, 5 degrees /55 degrees C, 30 seconds dwell time), and 2 sections were made longitudinally through the restorations with a low-speed diamond saw, producing approximately 1-mm wide samples. The samples were polished with silicon carbide paper of increasing grit (400-1000), demineralized (6N HCl, 30 seconds), deproteinized (2.5% NaOC1, 10 minutes), left to air dry for 24 hours in a desiccator under low vacuum pressure, gold sputtered and viewed under SEM (JEOL-JSM-6460LV). In the AdheSE, Contax and Futurabond NR specimens, resin tag penetration into the tubules and lateral tags could be seen. G-Bond showed different interface morphology, with a tight, thin continuous junction and almost no resin penetration into tubules. PQ Clear samples exhibited the highest number of resin tags with numerous lateral tags. A clearly defined hybrid layer was seen in the Contax and PQ Clear specimens. Investigated self-etching systems showed similar interfacial morphology with dentin, except for the 1 step/1 component adhesive G-Bond. The degree of demineralization and interaction with dentin correlated with the acidity of the self-etching primers/adhesives. Fewer resin tags were formed with self-etching primers/adhesives than with the etch and rinse system.

Acid Etching, Dental↗
PubMed2000

The effects of alcoholic compounds on the stability of type I collagen studied by differential scanning calorimetry.

The interaction between bovine tendon collagen and a series of homologous alcohols were investigated using a differential scanning calorimetry. For all alcoholic substances, as well as 2-hydroxyethyl methacrylate (HEMA), the concentration dependence of the denaturation temperature of collagen was observed, which showed a minimum at 30%. Clearly there are two opposing actions on the stabilization of the collagen structure; destabilization dominates over stabilization at lower concentrations, and vice versa at higher concentrations. The concentration dependence became greater for longer chain alcohols, while it was suppressed by the increased number of OH groups. The chain length-dependent surface tension may be related, which controls the permeation of the additives through the collagen fibers. Overall hydrophobicity, indicated by the hydrophile-lipophile balance (HLB) numbers, suggests the importance of the hydrophobic effect in the interaction of collagen and alcoholic substances, including adhesive monomers such as HEMA.

Alcohols↗
PubMed2000

WDX study of resin-dentin interface on wet vs. dry dentin.

The purpose of the present study was to determine the resin-dentin Interface conditions in Wet vs. Dry Dentin. Dentin disks were prepared from extracted human premolars. Sectioned dentin surfaces were used for SEM studies of wet vs. dried acid-etched dentin. These specimens were cut perpendicular to the surface into two equal halves. One-half of the sectioned specimen was observed by SEM in three treatment groups and the other half was observed for micromorphological differences in the resin-dentin interface using Wavelength Dispersive X-ray Spectrometer (WDX). SEM photomicrographs of the dentin surface showed the collapse of collagen fibrils in the demineralized layer and enlargement of the tubule orifices. A collagen rich layer approximately 8-10 microns thick (WDX) was observed at the resin-dentin interface when treated with the conventional dry-bonding technique. Dentin surfaces treated by the wet-bonding technique (SB), as observed by SEM, showed an uncollapsed collagen layer, while the collagen-rich layer was approximately 1-2 microns thick (WDX). The present findings suggest that moist bonding is required for optimum infiltration of adhesive resin into the demineralized layer.

Acid Etching, Dental↗
PubMed2004

Determination of elastic modulus of the components at dentin-resin interface using the ultrasonic device.

The purpose of this study was to determine the elastic moduli of the components at resin-dentin interface with the use of an ultrasonic device. Dentin plates were obtained from freshly extracted bovine incisors with a shape in rectangular form. Resin composites and bonding agents were polymerized and trimmed in the same shape as the dentin specimens. The ultrasonic equipment employed in this study was comprised of a Pulser-Receiver, transducers, and an oscilloscope. Each elastic modulus was determined by measuring the longitudinal and shear wave sound velocities. The mean elastic modulus of mineralized dentin was 17.4 GPa, while that of demineralized dentin was 1.4 GPa. When the demineralized dentin was immersed in bonding agents, the elastic modulus changed to 3.7-4.7 GPa, and these values were significantly higher than those of demineralized dentin. A gradient in elastic modulus was detected as the analysis shifted from the dentin side to the resin composite.

Analysis of Variance↗
PubMed2005

Micro-shear bond strength of five single-step adhesives to dentin.

The micro-shear bond strengths (MSBSs) of five single-step self-etch adhesives (Adper Prompt L-Pop [APL], AQ Bond plus [AQP], OBF-2 [OB2], Reactmer Bond [RB], and Xeno III [XIII]) were compared with that of a two-step self-etch adhesive, Clearfil SE Bond [SE]. The adhesives were applied on dentin surfaces, according to manufacturers' instructions, for bonding of resin composite to dentin. After 24 hours, a micro-shear bond test was carried out and the data were analyzed by one-way ANOVA and Bonferroni test (p<0.05). The mean MSBSs in MPa were APL: 22.8, AQP: 37.4, OB2: 34.7, RB: 28.3, XIII: 30.3, and SE: 47.2. Among the single-step adhesives, the MSBS of AQP and OB2 were significantly higher than APL (p<0.05). In conclusion, the single-step adhesives used in this study, apart from AQP, produced significantly lower MSBS than the two-step adhesive (p<0.05).

Acid Etching, Dental↗
PubMed2006

Effects of smear layer and surface moisture on dentin bond strength of a waterless all-in-one adhesive.

The purpose of this study was to evaluate the microtensile bond strength (MTBS) of a waterless all-in-one adhesive system, Absolute, to dentin. Eighteen human molars were either ground with 600-grit SiC paper or cut with a diamond bur. The following dentin bonding procedures were then performed: dentin surface was kept moist; dentin surface was dried; or dentin surface was dried but equivalent amount of water was added to the adhesive (1:1 by volume). After adhesive curing, a resin composite was incrementally built up. After the specimens were kept in water for one day, MTBSs were measured at a cross-head speed of 1 mm/min. Two-way ANOVA (p = 0.05) indicated that the MTBS of the adhesive system was not influenced by surface texture, but enhanced by the presence of water on tooth surface. It was concluded that water is essential to obtaining good dentin bonding for this adhesive system.

Analysis of Variance↗
PubMed1997

Dentinal adhesion and histomorphology of two dentinal bonding agents under the influence of eugenol.

This study examined the influence of eugenol on the dentinal adhesion of an enamel-dentin bonding agent that removes the smear layer (total-etch technique) and a system that partially dissolves the smear layer (self-conditioning adhesive system). The tensile bond strength was measured on flat, dentinal surfaces after application and removal of pure eugenol for 15 minutes and a eugenol-containing temporary luting agent for 24 hours. In addition, the resin-dentin interface was evaluated with confocal laser scanning microscopy. Dentinal adhesion was found to be significantly reduced after the application of eugenol when a dentin bonding agent that dissolves the smear layer was used. Under confocal laser scanning microscopy, the resin-dentin interdiffusion zone of both adhesive was found to be changed, not only after application of eugenol but also after application of a eugenol-containing temporary luting agent.

Adhesiveness↗
PubMed1999

In vitro comparison of 10-minute versus 24-hour shear bond strengths of six dentin bonding systems.

OBJECTIVE: Early bond strengths produced by dentin bonding systems should be sufficient to resist the polymerization shrinkage of resin composite. This study compared the 10-minute and 24-hour shear bond strengths of six dentin bonding systems: One-Step (OS), PermaQuik (PQ), Prime & Bond 2.1 (PB), Scotchbond Multi-Purpose (SBMP), Single Bond (SB), and Tenure Quik with Fluoride (TQ). METHOD AND MATERIALS: Each bonding system was used to bond composite to visibly moist dentin at 34 degrees C +/- 2 degrees C. The specimens were debonded at 37 degrees C +/- 1 degree C 10 minutes after the start of light curing of the bonding system, and the results were compared with the 24-hour bond strengths. The mode of failure was recorded. RESULTS: The 10-minute mean shear bond strengths were: OS, 16.4; PQ, 14.3; SB, 14.0; PB, 12.7; TQ, 10.7; and SBMP, 9.3 MPa. The 24-hour mean shear bond strengths were OS, 23.3; PB, 20.8; SB, 20.3; PQ, 19.4; TQ, 11.2; and SBMP, 10.0 MPa. The 10-minute mean shear bond strengths of OS, PQ, PB, and SB bonding systems were significantly less than the 24-hour values. More dentinal fractures and mixed failures were observed with OS, PQ, and PB. Systems with higher bond strengths had more resin penetration into the lateral dentinal branches. CONCLUSION: The 10-minute mean shear bond strengths were all less than 17 MPa, and the 10-minute bond strengths were less than the 24-hour values.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1999

An ultra-morphological characterization of collagen-depleted etched dentin.

PURPOSE: To evaluate the ultramorphology of superficial and deep dentin after etching with 35% phosphoric acid (H3PO4) and after etching with 35% H3PO4 followed by deproteinization with 5% sodium hypochlorite (NaOCl). MATERIALS AND METHODS: Two dentin disks (superficial and deep dentin) were obtained from each of 10 extracted human third molars by slow-speed sectioning. Dentin was polished with wet 600-grit SiC abrasive paper for 1 min to provide smooth surfaces. The occlusal surface of each disk was etched with 35% H3PO4 for 15 s and thoroughly rinsed. The specimens were kept moist and analyzed using Atomic Force Microscopy (AFM). Half of the specimens were deproteinized by rubbing with 5% NaOCl for 2 min, followed by a 30 s rinse with deionized water. After AFM analysis of the deproteinized specimens, all disks were fixed in a solution of glutaraldehyde and paraformaldehyde, dehydrated in ethanol and dried in hexamethyldisilazane. The dentin disks were then mounted on aluminum stubs for field-emission scanning electron microscope (FESEM) observation. RESULTS: The surface of etched dentin displayed a granular layer of silica, which did not reach the peritubular collagen area. The silica was more uniformly distributed in superficial dentin than in deep dentin. In spite of the silica deposition, the intertubular porosity remained unobstructed when observed at high magnification. Under a lateral view, intertubular dentin was demineralized to a depth of 2.0 to 2.5 microns for superficial dentin, and 2.5 to 3.0 microns for deep dentin. Deproteinization with 5% NaOCl removed the exposed collagen both for superficial and deep dentin. The number of open tubules was greater for deep dentin. Deproteinization of superficial dentin revealed an extensive labyrinth of lateral secondary tubules and anastomoses, which opened on the intertubular region and on the peritubular area close to the surface. This phenomenon decreased the area of exposed intertubular dentin as compared to etched specimens. In deproteinized deep dentin, the lateral anastomotic tubules were not consistently observed on the intertubular area, but were easily depicted on the peritubular area.

Acid Etching, Dental↗
PubMed1999

Saliva contamination and resin micromorphological adaptation to cavity walls using single-bottle adhesives.

PURPOSE: To examine and compare the effect of saliva contamination on the resin micromorphologic adaptation of four single-bottle adhesives. MATERIALS AND METHODS: Prime & Bond 2.1, One-Step, Tenure Quik with fluoride and Syntac Single Component adhesives were evaluated. Sixty sound molars were divided into three subgroups for each of the four adhesives; Class V cavities were prepared with gingival margins at cementum. Each adhesive was tested under: Normal conditions (Group 1), contamination of the cavity with fresh whole saliva for 20 seconds and removing the excess (Group 2), and contamination of the cavity with fresh whole saliva for 20 seconds and rinsing the saliva for 20 seconds before adhesive application (Group 3). After curing the adhesive, the cavities were filled with Z100 composite, fixed in 2.0% glutaraldehyde and sectioned into two halves. The sectioned halves were fixed again and rinsed with 0.2 M sodium cacodylate buffer. The cut surfaces were wet ground, polished and sonicated in distilled water. The specimens were immersed in decalcifying solution, deprotenized, serially dehydrated, mounted on aluminum stubs, sputter coated and examined under the SEM. RESULTS: The four adhesives formed hybrid layer with resin tags penetration into the dentin. P & B 2.1 showed usually funnel-shaped resin tags; One-Step, cylindrical shape; Tenure Quick and Syntac SC, variable shapes. Saliva contamination did not prevent hybrid layer formation or resin penetration into the dentin tubules. Only Syntac SC displayed a relatively thin hybrid layer with the unwashed saliva-contaminated group.

Bisphenol A-Glycidyl Methacrylate↗
PubMedDate not supplied

Effect of bonded amalgam restorations on microleakage.

The purpose of this study was to evaluate quantitatively the effectiveness of adhesive dentin bonding systems in decreasing microleakage at the tooth-amalgam restoration interface. The results indicated that microleakage was significantly reduced when Amalgambond Plus or All-Bond 2 was used as liners in comparison to either Copalite varnish or no linear under amalgam restorations. No significant difference was found between the two dentin bonding systems at all time periods studied.

Analysis of Variance↗
PubMedDate not supplied

Quantitative microleakage evaluation around amalgam restorations with different treatments on cavity walls.

The purpose of this in vitro study was to evaluate the dye penetration around amalgam restorations in dentin cavities by a quantitative test. Standardized circular cavities were prepared on the facial surface of 75 extracted human single-rooted teeth, and restored with dental amalgam. Different bonding/sealing treatments were used on the cavity walls before the restorations were placed. The specimens were thermo-cycled between 5 +/- 2 degrees C and 55 +/- 2 degrees C for 500 cycles with 1-minute dwell times, followed by immersion in a 2% methylene blue solution for 12 hours at 37 degrees C. The quantitative microleakage was evaluated by spectrophotometry and was expressed by microgram dye per tooth structure. The results showed that the use of bonded amalgam restorations was more effective in reducing microleakage.

Dental Amalgam↗
PubMed1999

Dentin bonding--state of the art 1999.

The adhesion of restorative materials to the hard components of tooth structure has been a goal pursued by many researchers ever since Buonocore established the foundation for adhesive and preventive dentistry. Based on the industrial use of phosphoric acid to obtain better adhesion of paints and resin coatings to metal surfaces, Buonocore proposed that phosphoric acid could be used to transform the surface of enamel to "render it more receptive to adhesion." Subsequent research indicated that the formation of taglike resin prolongations into the enamel microporosities was the leading bonding mechanism of resin to phosphoric acid-etched enamel. The enamel bonding agents of the 1960s and 1970s progressively evolved into complex multibottle or universal adhesives in the early 1990s, which were designed to bond to enamel, dentin, composite, amalgam, porcelain, and non-precious metal. Although bonding to enamel has been a dependable technique, bonding to dentin still represents an overwhelming task because dentin is a naturally wet organic tissue penetrated by a tubular maze containing the odontoblastic process, which communicates with the pulp. This intrinsic moisture may actually benefit the chemistry of the newest adhesive systems, which must be applied on moist dentin to be effective. In fact, the collapse of the collagen that occurs on air-drying may prevent the adhesive monomers from penetrating the network of nano-channels formed by the dissolution of hydroxyapatite crystals between collagen fibrils. In view of the complexity of the mechanisms associated with these mechanisms, the objective of this review article is to summarize the most recent concepts in dentin bonding.

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

Dentin bond strength and marginal adaption after NaOCl pre-treatment.

The aim of this in vitro study was to compare the dentin bond strength and marginal adaptation of direct composite resins with and without additional NaOCl treatment after the etching process. A total of 150 cavities were prepared into disks of freshly extracted human third molars and filled with direct composite resins. Dentin adhesives of the fourth (with total etching: Scotchbond Multi-Purpose Plus, EBS, and Solid Bond), and fifth generation (one-bottle adhesives: Prime&Bond 2.1, Syntac Sprint) were used in combination with corresponding composite resin materials. Dentin disks without cavity preparation treatment served as controls. After 24 hours of storage and 24 hours of thermocycling (1150 cycles), replicas were made and push-out testing was performed. Replicas were examined regarding marginal adaptation using SEM (X200 magnification). In general, fourth-generation dentin adhesives produced better results in bond strength and marginal adaptation than fifth-generation one-bottle systems (P < 0.05). Within the fourth generation, Scotchbond Multi-Purpose Plus and EBS achieved significantly higher push-out values and percentages of gap-free margins than Solid Bond (P < 0.05). After hypochlorite treatment, dentin bond strength (-25%) and marginal adaptation (-30%) decreased significantly (P < 0.05) in all groups.

Acetone↗
PubMedDate not supplied

Pulpal inflammatory responses following non-carious class V restorations.

The effects of inflammatory activity following surgical intervention can injure pulp tissues; in severe cases it can lead to pulpal complications. With this article, the authors report on the effects of cavity preparation and restoration events and how they can interact together to reduce or increase the severity of pulpal inflammatory activity in 202 restored Class V cavities. Although some inflammatory activity was observed in the absence of bacteria, the severity of pulpal inflammatory activity was increased when cavity restorations became infected. Zinc oxide eugenol and resin-modified glass ionomer cement prevented bacterial microleakage in cavity restorations, with no severe inflammatory activity observed with these materials. Bacteria were observed in cavities restored with enamel bonding resin and adhesive bonded composites and were associated with severe grades of inflammatory activity. The cavity remaining dentin thickness influenced the grade of inflammatory activity. In the absence of infection, the grade of inflammatory activity decreased after 20 weeks post-operatively. In the presence of infection, the grade of pulpal inflammation remained stable until a minimum of 30 weeks had elapsed.

Adolescent↗