Scotchbond Multi-Purpose Research Articles

Spectral Characteristics of Light-curing Units and Dental Adhesives

Most manufacturers do not provide details about the photoinitiators contained in dental adhesives. Therefore, it is difficult to choose an optimal combination of dental adhesive and light-curing unit. The purpose of this study was therefore to investigate the spectral emission characteristics of several commercially available light-curing units and the spectral transmittance characteristics of contemporary dental adhesives. Spectral distributions of emitted lights were determined on a UV-vis-NIR spectrometer for three quartz-tungsten-halogen (QTH) light-curing units (Jetlite 3000, J. Morita; New Light VL-2, GC; D-Lux 2000, Dentrade) and three light-emitting diode (LED) light-curing units (Curenos, Shofu; G-Light Prima, GC; Bluephase, Ivoclar Vivadent). Spectral distributions of light transmittance in contemporary dental adhesives (Scotchbond Multi-Purpose, 3M ESPE; Adper Single Bond, 3M ESPE; One-Step, Bisco; AQ Bond Plus, Sun Medical; OptiBond All-in-One, Kerr; Clearfil S3 Bond, Kuraray Medical; G-Bond, GC; Tokuyama Bond Force, Tokuyama Dental; GBA 300 experimental, GC) were also determined. Each of the three QTH light-curing units had a wide emission range of 380-510 nm. A narrower emission range was observed in the LED light-curing units than in the QTH light-curing units. It was found that 2 LED light-curing units had dual peak wavelengths in both the blue and violet regions of the visible spectrum. There were some variations in light transmittance, and therefore the results suggested that some dental adhesives contain alternative photoinitiators besides camphorquinone. The selection of suitable light-curing units on the basis of the light absorption of dental adhesives and resin composites in dental clinics is of upmost importance.

The effects of total-etch, wet-bonding, and light-curing of adhesive on the apical seal of a resin-based root canal filling system

Objectives: This study evaluated the effects of adhesion variables such as the priming concepts of canal wall and the curing modes of adhesives on the sealing ability of a resin-based root canal filling system. Materials and Methods: Apical microleakage of the Resilon-RealSeal systems filled with 3 different combinations of adhesion variables was compared with the conventional gutta-percha filling using a dye penetration method. Experimental groups were SEDC, Resilon (Resilon Research LLC) filling with self-etch RealSeal (SybronEndo) primer and dual-cure RealSeal sealer; NELC, Resilon filling with no etching, Scotchbond Multi-Purpose (3M ESPE) primer application and light-curing adhesive; and TELC, Resilon filling with Scotchbond Multi-Purpose primer and adhesive used under total etch / wet bonding and lightcure protocols. GPCS, gutta-percha filling with conventional AH26 plus sealer, was the control group. Results: The median longitudinal dye penetration length of TELC was significantly shorter than those of GPCS and SEDC (Kruskal-Wallis test, p

Biomechanical behavior of cavity configuration on micropush-out test: A finite-element-study

The objective of this study was to simulate the micropush-out bond strength test from a biomechanical point of view. For this purpose, stress analysis using finite element (FE) method was performed. Three different occlusal cavity shapes were simulated in disc specimens (model A: 1.5 mm cervical, 2 mm occlusal diameter; model B: 1.5 mm cervical, 1.75 mm occlusal diameter; model C: 1.5 mm cervical, 1.5 mm occlusal diameter). Quarter sizes of 3D FE specimen models of 4.0 x 4.0 x 1.25 mm3 were constructed. In order to avoid quantitative differences in the stress value in the models, models were derived from a single mapping mesh pattern that generated 47.182 elements and 66.853 nodes. The materials that were used were resin composite (Filtek Z250, 3M ESPE), bonding agent (Adper Scotchbond Multi-Purpose, 3M ESPE) and dentin as an isotropic material. Loading conditions consisted of subjecting a press of 4 MPa to the top of the resin composite discs. The postprocessing files allowed the calculation of the maximum principal stress, minimum principal stress and displacement within the disc specimens and stresses at the bonding layer. FE model construction and analysis were performed on PC workstation (Precision Work Station 670, Dell Inc.) using FE analysis program (ANSYS 10 Sp, ANSYS Inc.). Compressive stress concentrations were observed equally in the bottom interface edge of dentin. Tensile stresses were observed on the top area of dentin and at the half of lower side of composite under the loading point in all of the FE models. The FE model revealed differences in displacement and stress between different cavity shaped disc specimens. As the slope of the cavity was increased, the maximum displacement, compressive and tensile stresses also increased.

The effect of plasma polymer coating using atmospheric-pressure glow discharge on the shear bond strength of composite resin to ceramic

If plasma technology can come out of the vacuum chamber and plasma can be extruded through a small pencil-type torch, it can be applied widely to dental practices. For this study, we designed a small pencil-type non-thermal atmospheric-pressure glow discharge plasma torch. The purpose of this study was to determine the effect of plasma polymer coating on the adhesion of composite resin to feldspathic porcelain. The effect of plasma polymer coating was evaluated using shear bond strength (SBS) test. Contact angle measurements and fracture mode analysis were also performed. Among the groups treated with plasma polymer coating, the SBS of the adhesive (Adper Scotchbond Multi-Purpose, 3M ESPE) to the ceramic surface pre-treated sequentially with water plasma and triethyleneglycol dimethacrylate (TEGDMA) plasma in helium gas was significantly higher than that of the adhesive to the untreated surface (p < 0.05). In this group, the predominant fracture mode was mixed fracture, where small cohesively fractured fragments of ceramic were dispersed on the adhesively fractured flat adhesive surface. However, the SBS values of all the plasma polymer-coated groups were lower than those obtained through a routine porcelain bonding procedure with HF acid and silane coupling agent (p < 0.05). The non-thermal atmospheric-pressure plasma polymer coating technique was found to have a potential promoting adhesion to dental materials.

Influence of dental materials used for sealing caries lesions on laser fluorescence measurements

The aim of this study was to determine the influence of thickness and aging on the intrinsic fluorescence of sealing materials and their ability to block fluorescence from the underlying surface as assessed using a laser fluorescence device. Cavities of 0.5 mm and 1 mm depth were drilled into acrylic boards which were placed over two surfaces with different fluorescence properties: a low-fluorescence surface, to assess the intrinsic fluorescence of the sealing materials, and a high-fluorescence surface, to assess the fluorescence-blocking ability of the sealing materials. Ten cavities of each depth were filled with different sealing materials: Adper Scotchbond Multi-Purpose, Adper Single Bond 2, FluroShield, Conseal f and UltraSeal XT Plus. Fluorescence was measured with a DIAGNOdent pen at five different time points: empty cavity, after polymerization, and 1 day, 1 week and 1 month after filling. The individual values after polymerization, as well as the area under the curve for the different periods were submitted to ANOVA and the Tukey test (p < 0.05). At 0.5 mm, Scotchbond, FluroShield and UltraSeal showed insignificant changes in intrinsic fluorescence with aging and lower fluorescence after polymerization than Single Bond and Conseal. At 1 mm, Scotchbond and FluroShield showed the lowest intrinsic fluorescence, but only Scotchbond showed no chagnes in fluorescence with aging. At both depths, Scotchbond blocked significantly less fluorescence. All sealing materials blocked more fluorescence when applied to a depth of 1 mm. At 0.5 mm, fissure sealants blocked more fluorescence than adhesives, and did not show significant changes with aging. Scotchbond had the least affect on the fluorescence from the underlying surface and would probably have the least affect on the monitoring of sealed dental caries by laser fluorescence.

Relationship between Operator Skill and In Vitro Microleakage of Different Adhesive Systems in Class V Restorations

Objectives. The aim of this study was to evaluate the influence of operator skill on microleakage in class V composite restorations. Materials and Methods. A total of 16 dentists and 25 dental students were enrolled, and 123 extracted teeth were allocated according to the adhesive being tested: Scotchbond Multipurpose, Adper Scotchbond 1 XT, and AdheSE. Each operator was asked to restore one tooth from each experimental group: two class V cavities were cut on each tooth and each adhesive was used on the same tooth before and after instructions for its use. After filling cavities with composite (Z100), the teeth were thermocycled. Results. For all of the tested adhesives, the mean microleakage score was lower for the dentists than for the students. The mean scores for the three tested adhesives were statistically similar before and after instructions for use. Conclusion. Our results indicate that the skill of the operator has a significant influence on microleakage.

The effect of curing light and chemical catalyst on the degree of conversion of two dual cured resin luting cements

The aim of this study was to evaluate the influence of different curing lights and chemical catalysts on the degree of conversion of resin luting cements. A total of 60 disk-shaped specimens of RelyX ARC or Panavia F of diameter 5 mm and thickness 0.5 mm were prepared and the respective chemical catalyst (Scotchbond Multi-Purpose Plus or ED Primer) was added. The specimens were light-cured using different curing units (an argon ion laser, an LED or a quartz-tungsten-halogen light) through shade A2 composite disks of diameter 10 mm and thickness 2 mm. After 24 h of dry storage at 37°C, the degree of conversion of the resin luting cements was measured by Fourier-transformed infrared spectroscopy. For statistical analysis, ANOVA and the Tukey test were used, with p ≤ 0.05. Panavia F when used without catalyst and cured using the LED or the argon ion laser showed degree of conversion values significantly lower than RelyX ARC, with and without catalyst, and cured with any of the light sources. Therefore, the degree of conversion of Panavia F with ED Primer cured with the quartz-tungsten-halogen light was significantly different from that of RelyX ARC regardless of the use of the chemical catalyst and light curing source. In conclusion, RelyX ARC can be cured satisfactorily with the argon ion laser, LED or quartz-tungsten-halogen light with or without a chemical catalyst. To obtain a satisfactory degree of conversion, Panavia F luting cement should be used with ED Primer and cured with halogen light.

The Effect of Oxalate Desensitizers on the Microleakage of Resin Composite Restorations Bonded by Etch and Rinse Adhesive Systems

This in vitro study evaluated the effect of an oxalate desensitizer (OX) on the marginal microleakage of resin composite restorations bonded by two three-step and two two-step etch and rinse adhesives. Class V cavities were prepared on the buccal surfaces of 126 extracted premolars at the cementoenamel junction and randomly divided into nine groups of 14 each. In the control groups (1-4), four adhesives were applied, respectively, including Adper Scotchbond Multi-Purpose (SBMP), Optibond FL (OBFL), One-Step Plus (OS) and Excite (EX). In the experimental groups (5-8), the same adhesives, in combination with OX (BisBlock), were applied. And, in one group, OX was applied without any adhesive, as the negative control group (9). All the groups were restored with a resin composite. After 24 hours of storage in distilled water and thermocycling, the samples were placed in 1% methylene blue dye solution. The dye penetration was evaluated using a stereomicroscope. The data were analyzed using non-parametric tests. The OX application, in combination with OBFL and EX, resulted in significantly increasing microleakage at the gingival margins (p < 0.05), while it had no effect on OS and SBMP (p > 0.05). At the occlusal margins, no significant difference in microleakage was observed after OX application for each of four adhesives (p > 0.05).

Effects of immersion time and frequency of water exchange on durability of etch‐and‐rinse adhesive

This study evaluated the immediate and long-term bond strength to dentin (microtensile bond strength, μTBS) and silver nitrate uptake (SNU) of a three- and two-step etch-and-rinse adhesive under different water immersion times and frequency of water exchange. The adhesives and composite resin were applied according to the manufacturer's instructions in a flat occlusal demineralized dentin of 48 molars. Teeth were assigned to four groups of immersion time (immediate and 1, 3, and 6 months), sectioned to obtain resin-dentin beams, and then subdivided into three groups of water exchange (daily, weekly, and monthly) before being tested in tension. Two resin-dentin beams from each tooth were immersed in silver nitrate and analyzed by SEM. Significant difference in μTBS and SNU was detected for both adhesives (p ≤ 0.0001 for the cross-product interaction). For Adper Single Bond 2, the most pronounced reductions of μTBS were observed for the daily exchange groups in all times. For Adper Scotchbond Multi Purpose, 1-month immersion period was not capable to induce degradation of the dentin bonds, except when the water was exchanged daily. For both adhesives, all storage regimens showed increased SNU results only after 6-month water storage; this being more pronounced for daily water exchange groups. For both adhesives, the highest SNU was observed in the daily water exchange group. The daily water exchange is a fast and reliable in vitro aging method for testing the durability of the adhesive interface produced by adhesive systems.

Marginal leakage in permanent teeth after dentin treatment with air abrasion and adhesive systems

Due to doubts related to the application and association of techniques for appropriate adhesion, as the air abrasion system and last generation adhesive systems, the objective of this study was to evaluate the marginal leakage in Class V composite restorations in permanent teeth prepared with rotating instruments and then submitted to air abrasion and adhesive systems. Cavities were prepared with burs in high speed in facial and lingual surfaces of 25 human third molars. The specimens were divided into 5 groups of 10 preparations each: G1 (air abrasion and Scotchbond Multi Purpose), G2 (phosphoric acid and Scotchbond MP), G3 (Clearfil SE Bond self-etching system), G4 (air abrasion, phosphoric acid and Scotchbond MP) G5 (air abrasion and Clearfil SE Bond). All groups were restored with Z100 composite resin. The teeth were subjected to thermal cycling and immerged in 50% silver nitrate solution. After sectioning, the specimens were analyzed with a stereomicroscope for assessment of microleakage according to the degree of dye penetration. The Kruskal-Wallis test followed by Dunn Multiple Comparison test were performed in order to evaluate the differences among the experimental groups. Air abrasion groups demonstrated the greatest leakage. Scotchbond MP with phosphoric acid produced the least leakage, with greater leakage in gingival margins than occlusal margins in all experimental groups. It was concluded that dentin treatment with air abrasion should not be used in permanent teeth to reduce the marginal leakage.

Etching time evaluation on the shear bond strength of two adhesive systems in primary teeth

Purpose: to evaluate the effect of the etching time and adhesive systems on the shear bond strength in primary teeth. Methodology: 48 sound primary teeth (USP teeth bank) were used. They were longitudinally sectioned (mesio-distal direction) and embedded in epoxy resin, leaving the buccal or lingual surface externally. The specimens were ground flat until dentin. They were randomly divided into 3 groups according to the etching time (7, 15 and 20 s) and the adhesive system used (Scotchbond Multipurpose Plus - SBMP and Prime &amp; Bond 2.1 - PB): G1 - 7s + SBMP; G2 - 15 s + SBMP; G3 - 20 s + SBMP; G4 - 7 s + PB; G5 - 15 s + PB; G6 - 20 s + PB. Next the teeth were restored (Z100), on the dentin surface and stored in distilled water (37oC, for 72h). Then, the specimens were submitted to the SBS test in an Instron machine (0.5 mm/min). The fracture sites were analyzed in a Stereomicroscopic and SEM. The values for the SBS test were submitted to ANOVA and Tukey tests (p&lt;0.05). Results: the SBS was higher for the 7s time groups. However, no statistical difference was observed when SBwas used. The PB system showed higher values of SBS at 7 and 15s (p&lt;0.05). The adhesive failure (86.5%) was more frequent. Conclusion: 1 - The interaction material versus time showed that for the SBMP the performance of the system did not vary due to the etching time, while for the PB the best results were found for the lower times of acid etching; 2 - The analysis of fractured sites showed that the most frequently failure type found was the adhesive type (86.5%); 3 - The larger the etching time the lower the shear bond strength values for the PB adhesive system.

Shear resistance evaluation on the enamel surface of deciduous teeth following acid etching with or without previous air abrasion

The purpose of this study was to evaluate the shear resistance of a composite resin to the enamel surface of deciduous teeth after acid etching surface with or without previous air abrasion. Sixteen sound exfoliated deciduous incisors were assigned to 2 groups. Group I was acid etched with 37% phosphoric acid and Group II was air abraded with 50-mm aluminum oxide particles for 15 seconds, at 80 psi and a 5-mm distance from the dental surface. The adhesive system Scotchbond Multi Purpose and Z100 composite resin was applied on both experimental groups. The Student’s t test de­monstrated significant statistical difference between the groups (p=0.0001). The mean shear bond strengths for groups I and II are 10.65 MPa and 6.32 MPa, respectively. The authors concluded that the maximum bond strength was achieved by isolated acid etching, which yielded a significantly larger shear resistance than in combination with air abrasion.

Effect of pretest storage conditions of extracted teeth on their dentin bond strengths

It is becoming increasingly difficult to obtain sufficient freshly extracted human teeth to utilize in in vitro studies, particularly for bonding investigations. The purpose of this study was to investigate the effect of different storage conditions for human extracted teeth prior to their use in microtensile bond strength (microTBS) testing. Thirty incisors were divided into groups according to their storage time and condition. The first group consisted of freshly extracted teeth. Teeth of the second group were stored in chloramine-T at 4 degrees C for 2 years +/-1 month. The last group was stored dry for up to 2 years +/-2 months, after which teeth were rehydrated in distilled water for 2 weeks before use. All teeth were disinfected using 0.5% chloramine-T. Dentin surfaces were exposed and then bonded using Scotchbond Multi-Purpose or Clearfil SE Bond to composite resin foundations (Esthet-X). Following 24-hour storage, bonded teeth (n=30) were sectioned into beams with a cross-section of 0.9 +/-0.1 mm(2) and subjected to microTBS testing using a microtensile testing machine (Micro Tensile Tester). Data were calculated and statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (alpha=.05). Failure modes were determined using a stereomicroscope at x40 magnification. Statistical analysis revealed no significant difference between the different storage conditions nor between the 2 adhesive systems for each storage condition (P>.05). Modes of failure for all tested groups were predominantly adhesive followed by mixed. Within the limitations of this study, it was concluded that aging of teeth and storage conditions had no significant effect on dentin microtensile bond strength to composite resin.

Zirconia nanoparticles prepared by laser vaporization as fillers for dental adhesives

Zirconia nanoparticles prepared by laser vaporization were incorporated into the primer or into the adhesive of a commercial adhesive system in order to evaluate its effect on bond strength to dentin. Zirconia nanoparticles (20-50nm) were prepared using a particular laser vaporization technique and incorporated into the primer (P) or into the adhesive (A) of the Adper Scotchbond Multi-Purpose (SBMP) system at 5, 10, 15 and 20wt.% by means of mechanical mixing (stirring) and ultrasonication. Control (unfilled) and experimental groups (filled) were applied, according to the manufacturer's instructions, onto flat mid-coronal human dentin. Composite crowns were built up, stored in distilled water for 24h at 37°C and cut into 0.65±0.05mm² beams following a non-trimming microtensile technique. Specimens were fractured in tension using a universal testing machine (Zwick) and examined by scanning electron microscopy for fractographic analysis. Microtensile bond strength (μTBS) data were analyzed using a two-way ANOVA and modified LSD test at α=0.05. Analysis of the nanofiller distribution and ultramorphological characterization of the interface were performed by transmission electron microscopy (TEM). Zirconia nanoparticle incorporation into the primer or into the adhesive of SBMP significantly increased μTBS to dentin. Filler concentration only affected μTBS significantly in the P group. Statistically significant differences between groups P and A occurred only at 20wt.% filler content, with a significantly higher μTBS in group P. TEM micrographs revealed nanoparticle deposition on top of a hybrid layer when incorporated into the primer, whereas they remained dispersed through the adhesive layer in group A. Zirconia nanoparticles incorporation into SBMP increased bond strength to dentin by reinforcing the interface adhesive layer. Nanofiller incorporation into the primer solution showed a tendency of increasing bond strength with increasing concentration. At high concentrations (20wt.%) nanofiller incorporation was more efficient in increasing bond strength if incorporated in the primer solution. Adding nanofillers to the primer and to the adhesive solutions resulted in different particle distributions at the interface.

The effect of ageing on the elastic modulus and degree of conversion of two multistep adhesive systems

During the curing reaction, the monomers of dentine bonding systems should cross-link sufficiently to strengthen an adhesive so that it is clinically reliable. This study evaluated how different storage conditions (air vs. water storage) affect the elastic modulus (E-modulus) and degree of conversion (DC) of a three-step etch-and-rinse adhesive and a two-step self-etch adhesive. The biaxial flexural test and Raman microscopy were performed on resin disks made from the bonding agents Adper Scotchbond Multi-Purpose (SBMP; 3M ESPE) and Clearfil Protect Bond (CPB; Kuraray). The measurements were repeated after storage in either air or water for 15 and 30 min and for 1, 24, and 72 h. At time 0, the E-modulus was not affected by the adhesive system, whilst the degree of cure of CPB was higher than that of SBMP. Air storage increased the E-modulus at each ageing interval. Storage in water increased the E-modulus until it reached a maximum at 24 h, after which it decreased significantly at 72 h. No linear correlation between the percentage DC and E-modulus of the two adhesives was found when stored in water. The results of this study indicate that the mechanical properties and polymerization kinetics of SBMP and CPB are affected by storage time and medium.

Flexural strength of glass fibre‐reinforced posts bonded to dual‐cure composite resin cements

The aims of this study were to evaluate the flexural strength of two different types of glass fibre-reinforced posts bonded to dual-cure composite resin cements. Forty glass methacrylate-based fibre posts (GC Fiber Post) and 20 glass fibre inter-polymerizing network posts (everStick POST) were divided into three groups. Group 1 contained 20 GC posts that were bonded to a dual-cure composite cement (UnifilCore). Group 2 contained 20 Stick Tech posts that had adhesive applied (Scotchbond Multipurpose resin) and were bonded to a dual-cure composite resin cement (RelyX Unicem). Group 3 contained 20 GC posts that were pretreated with a silane-coupling agent before being treated with resin and composite, as in group 1. A 4-point bend test was carried out to failure on all of the groups. Failure modes were determined using scanning electron microscopy. Pretreatment of the post surface with the silane-coupling agent did not increase the flexural strength. The flexural strength of the Stick Tech post was significantly lower than the flexural strength of the GC post. The mode of failure for the GC Posts was adhesive, whereas the Stick Tech posts failed cohesively. Different flexural strengths and failure modes were observed among the two fibre post-resin systems.

One-year stability of resin–dentin bonds created with a hydrophobic ethanol-wet bonding technique

Dentin bonding performed with hydrophobic resins using ethanol-wet bonding should be less susceptible to degradation but this hypothesis has never been validated. Objectives This in vitro study evaluated stability of resin–dentin bonds created with an experimental three-step BisGMA/TEGDMA hydrophobic adhesive or a three-step hydrophilic adhesive after one year of accelerated aging in artificial saliva. Methods Flat surfaces in mid-coronal dentin were obtained from 45 sound human molars and randomly divided into three groups ( n = 15): an experimental three-step BisGMA/TEGDMA hydrophobic adhesive applied to ethanol (ethanol-wet bonding—GI) or water-saturated dentin (water-wet bonding—GII) and Adper Scotchbond Multi-Purpose [MP—GIII] applied, according to manufacturer instructions, to water-saturated dentin. Resin composite crowns were incrementally formed and light-cured to approximately 5 mm in height. Bonded specimens were stored in artificial saliva at 37 °C for 24 h and sectioned into sticks. They were subjected to microtensile bond test and TEM analysis immediately and after one year. Data were analyzed with two-way ANOVA and Tukey tests. Results MP exhibited significant reduction in microtensile bond strength after aging (24 h: 40.6 ± 2.5 a; one year: 27.5 ± 3.3 b; in MPa). Hybrid layer degradation was evident in all specimens examined by TEM. The hydrophobic adhesive with ethanol-wet bonding preserved bond strength (24 h: 43.7 ± 7.4 a; one year: 39.8 ± 2.7 a) and hybrid layer integrity, with the latter demonstrating intact collagen fibrils and wide interfibrillar spaces. Significance Coaxing hydrophobic resins into acid-etched dentin using ethanol-wet bonding preserves resin–dentin bond integrity without the adjunctive use of MMPs inhibitors and warrants further biocompatibility and patient safety's studies and clinical testing.

Resin–dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding

Objective To compare resin–dentin bond strengths and the micropermeability of hydrophobic vs. hydrophilic resins bonded to acid-etched or EDTA-treated dentin, using the ethanol wet-bonding technique. Methods Flat dentin surfaces from extracted human third molars were conditioned before bonding with: 37% H 3PO 4 (15 s) or 0.1 M EDTA (60 s). Five experimental resin blends of different hydrophilicities and one commercial adhesive (SBMP: Scotchbond Multi-Purpose) were applied to ethanol wet-dentin (1 min) and light-cured (20 s). The solvated resins were used as primers (50% ethanol/50% comonomers) and their respective neat resins were used as the adhesive. The resin-bonded teeth were stored in distilled water (24 h) and sectioned in beams for microtensile bond strength testing. Modes of failure were examined by stereoscopic light microscopy and SEM. Confocal tandem scanning microscopy (TSM) interfacial characterization and micropermeability were also performed after filling the pulp chamber with 1 wt% aqueous rhodamine-B. Results The most hydrophobic resin 1 gave the lowest bond strength values to acid-etched dentin and all beams failed prematurely when the resin was applied to EDTA-treated dentin. Resins 2 and 3 gave intermediate bond strengths to both conditioned substrates. Resin 4, an acidic hydrophilic resin, gave the highest bond strengths to both EDTA-treated and acid-etched dentin. Resin 5 was the only hydrophilic resin showing poor resin infiltration when applied on acid-etched dentin. Significance The ethanol wet-bonding technique may improve the infiltration of most of the adhesives used in this study into dentin, especially when applied to EDTA-treated dentin. The chemical composition of the resin blends was a determining factor influencing the ability of adhesives to bond to EDTA-treated or 37% H 3PO 4 acid-etched dentin, when using the ethanol wet-bonding technique in a clinically relevant time period.

Real-time measurement of dentinal fluid flow during amalgam and composite restoration

This study examined changes in the dentinal fluid flow (DFF) during restorative procedures and compared permeability after restoration among restorative materials and adhesives. A class 1 cavity was prepared and restored with either amalgam (Bestaloy), or composite (Z-250) with one of two etch-and-rinse adhesives (Scotchbond MultiPurpose: MP and Single Bond 2: SB) or one of two self-etch adhesives (Clearfil SE Bond: CE and Easy Bond: EB) on an extracted human third molar which was connected to a sub-nanoliter fluid flow measuring device (NFMD) under 20 cm water pressure. DFF was measured from the intact tooth state through the restoration procedures to 30 min after restoration, and re-measured at 3 and 7 days post-restoration. Inward flow during cavity preparation was followed by outward flow after preparation. In amalgam restoration, the outward flow changed into an inward flow during amalgam filling, which was followed by a slight outward flow after finishing. In composite restoration, MP and SB showed an inward flow and outward flow for the rinsing and drying steps, respectively. Application of a hydrophobic bonding resin in the MP and CE systems caused a decrease in the flow rate. Air-drying of solvent for the CE and EB systems caused a sudden outward flow, whereas light-curing of the adhesive and composite caused an abrupt inward flow. Each restorative step clearly changed the direction and the rate of the DFF during restoration, which could be well identified with NFMD.

Clinical Evaluation of Bonded Amalgam Restorations in Endodontically Treated Premolar Teeth: A One-Year Evaluation

The aim of this clinical study was to compare the fracture resistance, marginal adaptation, and rate of recurrent caries of bonded and nonbonded amalgam restorations in endodontically treated premolar teeth. A total of 36 patients with endodontically treated maxillary first or second premolars were selected and divided into three groups. The treatments in all groups consisted of lingual cusp coverage and cementation of a prefabricated intracanal post (No. 2 long, Dentatus USA, New York, NY, USA). One type of cavity liner was used for each group as follows: copal varnish (Group A), Amalgambond Plus (Group B), and Scotchbond Multi-Purpose (Group C). The teeth were then restored with Cinalux high-copper spherical amalgam (Cinalux, Sh. Dr Faghihi Dental Co., Tehran, Iran). After one year, fracture resistance, marginal adaptation, and secondary caries were evaluated. Fischer's exact test was used for statistical analysis using a 0.05 percent significance level. There was no significant difference among groups with respect to fracture resistance (p=0.49). However, significant differences in marginal adaptation existed among the three groups (p=0.02) and no recurrent caries were found in any of the restored teeth. Bonding amalgam restorations using Amalgambond Plus and Scotchbond Multi-Purpose Plus did not improve the fracture resistance or affect the resistance to secondary caries in endodontically treated premolar teeth. However, the teeth in both these bonded groups showed significant improvement in marginal adaptation compared with restorations placed with copal varnish (p=0.02). Amalgambond Plus or Scotchbond Multi-Purpose adhesive resins significantly improved marginal adaptation of amalgam compared with copal varnish, but did not enhance fracture resistance or affect the prevention of secondary caries.