Scotchbond Multi-Purpose Research Articles

Torsional resistance of crowns cemented to composite cores involving three stainless steel endodontic post designs

Statement of Problem: There are no studies analyzing the effects of a crown in relationship to torsional resistance for a titanium-reinforced core material supported by a post. Purpose: This study investigated the effects of post design on the torsional resistance of a crown supported by a titanium-reinforced composite core material (Ti-Core) and 3 endodontic posts (AccessPost, Flexi-Post, and ParaPost). Material and Method: Three groups of 10 specimens per group were studied. A total of 30 recently extracted human single-rooted (incisors) teeth with their crowns removed were used. Post holes preparations were created according to manufacturer’s instructions. All posts were cemented using Flexi-Flow with titanium cement. Scotchbond Multi-Purpose bonding system was used as the bonding system for all groups. All cores were fabricated with Ti-Core with titanium core material with hard copper bands as the matrix. The Ti-Core core material was allowed to set for 1 hour. Metal crowns were fabricated and cemented with zinc phosphate cement. Specimens were placed in a special jig and a clockwise torsional force was applied. Torsional force was measured on a Lebow 1102-200 torque transducer and recorded on a Hewlett Packard 7015B X-Y recorder in inch × ounce. A 1-way analysis of variance (ANOVA) was used to test for statistical significance (P <.00l). Results: The torsional values (inch × ounce) were AccessPost 77.2 ± 30.3, Flexi-Post 162.2 ± 51.2, and ParaPost 60.9 ± 28.4. SNK and Scheffé comparison tests revealed that the Flexi-Post group had significantly greater resistance to torque loading than the AccessPost and ParaPost groups, which were statistically similar to each other. Conclusion: Post design has an effect on torsional resistance of a crown supported by titanium-reinforced core build-up and post. The threaded split-shank design of the Flexi-Post dowel offers significantly greater resistance to torsional loading than the passive posts studied. (J Prosthet Dent 2000;84:38-42.)

Evaporation of solvent in one-bottle adhesives

Objective: To compare the evaporation of vehicles included in different single-bottle adhesives as a function of time. Methods: The following adhesives were used: Prime and Bond 2.1 (Dentsply); Single Bond (3M); PrimaBond 97' (BJM); Syntac Sprint (Vivadent); Optibond Solo (Kerr) and Syntac Single Component (Vivadent). Two primers that are used in multiple-component adhesives (PermaQuick Primer, Ultradent and Scotchbond Multipurpose Primer, 3M) as well as distilled water, 96% ethanol and acetone were also included in the experiment. Samples of these products were stored in small glass containers under controlled temperature and humidity conditions. Initials mass and mass after different periods of time were registered to calculate the percentage loss of mass. Results: The analysis of variance of the results followed by orthogonal contrast comparisons revealed a significantly higher loss of mass in the single-bottle adhesives that contain organic vehicles (especially in those in which the vehicle was acetone). A somewhat lower loss of mass was found in a water-based product. Conclusion: There is a relationship among the evaporation possibilities of the vehicles used in single-bottle adhesive systems and their loss of mass during storage.

Influence of disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent

The purpose of the present study was to evaluate the influence of different disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent. Forty non carious human molars were selected. Teeth were embedded in acrylic resin and ground until the exposure of a flat superficial dentin surface. Teeth were randomly divided in 4 groups and treated as follows: Group 1 - 2.5% NaOCl for 40 seconds; Group 2 - 2% chlorhexidine for 40 seconds; Group 3 - 1.23% acidulated fluoride for 4 minutes; and Group 4 - control (without disinfectant solution). Following treatments, Scotchbond Multipurpose Plus® (3M) was used according to the manufacturer’s instructions. After that, the test specimens were built with composite resin (Z100®-3M), using a standard Teflon matrix. The specimens were stored in distilled water for 24 hours at a temperature of 37ºC. The tensile strength test was performed using a Mini Instrom testing machine. The mean values obtained for each group, in MPa, were: Group 1 - 7.37 (± 2.51); Group 2 - 11.25 (± 4.65); Group 3 - 9.80 (± 3.11); and Group 4 - 10.96 (± 3.37). The results were submitted to statistical analysis using the ANOVA test, and no statistical significant differences among the groups were found. It can be concluded that the different disinfectant substances used in this research do not adversely affect dentin adhesion.

Human pulp reaction to dentine bonded amalgam restorations: a histologic study

Objective: The aim of this study was to investigate the human pulp response to Scotchbond Multi Purpose Plus (SMPP) bonding agent in non-exposed Class V cavities. Methods: SMPP was placed in 24 of 40 cavites according to manufacturer's instructions and the cavities were restored with amalgam. The remaining 16 cavities were capped with a calcium hydroxide formulation (Dycal) sealed with zinc-oxide eugenol, and restored with the amalgam. After extraction at 10 and 35 days, the teeth were fixed, sectioned and stained for light microscopy. Results: All Dycal-capped teeth, at both 10 and 35 days, exhibited no pulp inflammation and no demonstrable bacteria. Six cases sealed with SMPP at 10 days showed no pulp inflammation or stained bacterial profiles. The remaining six teeth demonstrated mild to moderate inflammatory pulpal responses and five out of these six cases exhibited stained bacterial profiles. Nine out of 12 teeth showed no inflammatory pulp responses at 35 days, the remaining three cases exhibited mild to moderate pulp inflammation without stained bacteria. Conclusions: None of the teeth sealed with SMPP presented severe inflammatory pulpal reactions histologically. SMPP did not exhibit significant deleterious effects on the human pulp tissue during the test periods.

Fluoride release from glass ionomer cements and resin composites coated with a dentin adhesive

Objectives: This laboratory study compared the effect of surface coatings on patterns and amounts of fluoride released from four glass ionomer cements and two fluoride-containing resin composites. Methods: Twelve cylinders of each material were prepared in a polyethylene mold. The experimental groups ( n=6) were coated with one layer of an adhesive resin (3M Scotchbond Multipurpose Adhesive), while the control groups ( n=6) remained uncoated. Cumulative fluoride release into deionized water was measured on days 1, 2, 3, 7, 14, 21 and 28 using an ion analyzer. Total fluoride release after 28 days was analyzed for significant differences among materials using one-way ANOVA and Student–Newman–Keuls test ( p<0.05). Results: The total amounts of fluoride release from the coated samples were found to be significantly less than the uncoated samples for all materials, except Solitaire. The uncoated samples released a total amount of fluoride of between 2.3 and 85.4 ppm, while the coated samples released a total amount of fluoride of between <0.2 and 24.1 ppm. Similar patterns of fluoride release were found in coated and uncoated samples. Significance: The results indicated that the application of a dentin adhesive coating did not completely prevent fluoride release from glass ionomer cements and fluoridated resin composites, although the amounts were significantly less. Clinically, it suggests that a continued release of fluoride from glass ionomer cements and fluoridated resin composites is possible after placing a thin layer of resin adhesive. The clinical significance of these findings is not known.

Pulpal response of dogs primary teeth to an adhesive system or to a calcium hydroxide cement

The aim of this study was to evaluate the pulpal response of dogs primary teeth to an adhesive system or to a calcium hidroxide cement after mechanic exposure of the pulp. Three mongrel dogs were used and ten class V cavities were prepared on their teeth. A mechanic pulp exposure was produced with a sterile exploratory probe in the central portion of each cavity and bleeding was controlled with dry sterile cotton pellets. Enamel, dentin and the site of the pulp exposure of five teeth were etched with 35% phosphoric acid followed by the application of an adhesive system (Scotchbond Multi-Purpose - 3M). In the other five teeth, calcium hydroxide cement (Hydro C - Dentsply) was applied on the site of the pulp exposition before application of the adhesive system (Scotchbond Multi-Purpose - 3M). All teeth were restored with a resin composite (Z-100 - 3M). After 7, 30 or 45 days the dogs were anesthetized and perfused with saline followed by a solution of neutral buffered formalin. Maxilla and mandible were sectioned into three parts and placed in a solution for demineralization. Following bone demineralization, all teeth were cut, trimmed, embedded in paraffin and longitudinally cut. Then, the teeth were stained with hematoxilin and eosin and observed under a light microscope. The results obtained with the treatments proposed in this study showed the presence and persistence of an inflammatory response of different intensities at the three experimental periods. There was no variation in the inflammatory response regarding the different treatments performed.

Avaliação da infiltração marginal de restaurações de amálgama: mercúrio versus gálio

As restaurações de amálgama sofrem hoje uma série de questionamentos em relação a presença de mercúrio na sua composição e ligas alternativas foram desenvolvidas para a substituição desse material. Neste estudo avaliamos a infiltração marginal de duas ligas de amálgama (com mercúrio e com gálio) conjuntamente com dois sistemas adesivos (PAAMA e Scotchbond Multi-Uso Plus) em cavidades de classe V (margens em esmalte e cemento). Foram utilizados dentes humanos que após serem restaurados foram termociclados (500 ciclos, 5ºC-55ºC, 15 s em cada banho) e inseridos em corante (azul de metileno) e então desgastados e avaliados. Os escores foram compilados e submetidos a análise estatística (teste de Kruskal-Wallis com significância de 1%). Baseados nos resultados encontrados, pode-se concluir que houve diferença significante entre os adesivos utilizados, sendo melhor o sistema Scotchbond Multi-Uso Plus, não havendo diferença estatística entre as ligas de amálgama e nem entre as paredes.

Tooth wear treated with direct composite restorations at an increased vertical dimension: Results at 30 months

Statement of problem. Severe tooth wear localized to the anterior maxillary or mandibular teeth with loss of interocclusal space is difficult to manage. Purpose. This study evaluated the outcome of composite restorations placed at an increased vertical dimension of occlusion in such patients. Methods and material. Sixteen patients were restored with 104 restorations in 2 groups. In group A, Durafill composite and Scotchbond Multipurpose dentine adhesive system were used to place direct anterior restorations (N = 52). In group B, Herculite XRV composite and Optibond dentine bonding agent was used (N = 52). The restorations were placed at an increased vertical dimension of occlusion creating a posterior disclusion of 1 to 4 mm. Results. Clinical follow-up showed that the posterior occlusion remained satisfactorily restored after a mean duration of 4.6 months (range 1 to 11 months). Mean follow-up of 30 months has shown a combined success rate of 89.4% for both groups with 93 of the restorations remaining in service. Maintenance in group A was high with 33 failures, but low in group B with 6 failures. Patient satisfaction was reported as good. Conclusion. Direct composite restorations may be a treatment option for localized anterior tooth wear. (J Prosthet Dent 2000;83:287-93.)

Resin shear bond strength to porcelain and a base metal alloy using two polymerization schemes

Statement of problem. Fractures in ceramometal restorations can occur and need to be repaired because replacements are not an economic solution.Purpose. This study evaluated the shear bond strengths of 4 porcelain repair systems (Metabond C&B [ME], Silistor [SI], Clearfil Lustre [CL], and Scotchbond Multipurpose Plus [SQ]) to a base metal alloy and porcelain in relation with the polymerization shrinkage of a visible light-cured composite superstructure and compared with the ceramometal bond strength (Vita VMK 68).Material and methods. Thirty-two samples were prepared for each bonding system: 16 for resin-metal bond strength test, and 16 for resin-porcelain bond strength test. For each group, bonding agent was applied to 8 substructures and the resin superstructure was polymerized onto the bonding agent; and for the remaining 8 specimens, prepolymerized resin superstructures were bonded with bonding agent. All specimens were subjected to 500 cycles between 5°C and 55°C with 20 seconds dwell time. Tests were performed in a mechanical testing machine with a 0.5 mm/min crosshead speed.Results. All materials showed an increase in shear bond strength when prepolymerized resin superstructures were used. However, the effect of polymerization shrinkage of resin superstructure was statistically significant only for CL group (P<.05). The highest metal-resin bond was obtained from ME group with prepolymerized resin superstructures (35.27 ± 2.40 MPa), and the lowest value was obtained for the SI group in which resin superstructures were polymerized in situ (8.71 ± 1.03 MPa). The highest porcelain-resin bond was obtained from SC group with prepolymerized resin superstructures (20.71 ± 1.13 MPa) and the lowest was obtained from SI group (9.99 ± 1.52 MPa).Conclusion. Higher bond strength values were obtained with prepolymerized resin superstructures compared to in situ polymerized superstructures. Metabond C&B provided the best results for both prepolymerized and in situ polymerized resin superstructure preparation techniques at the failures where metal was exposed. The best results in situations in which the fracture is limited into porcelain were obtained with the use of Scotchbond Multipurpose Plus material. However, a variety of in vivo and in vitro tests are required before a final judgment is made.

Dentin shear bond strength of compomers and composites

Objective: The aim of this study was to compare the shear bond strengths and fracture characteristics of two compomers bonded with a single step bonding agent with two modern composites, a microfil and hybrid, bonded with a fourth generation bonding agent. Methods: Freshly extracted human third molars were sectioned parallel to the occlusal surface to expose midcoronal dentin, prepared with 320-grit surface finish, and bonded (N=11 samples/group) following manufacturer's directions with the compomers (Dyract, DeTrey Konstanz, Germany or Compoglass, Vivadent, Schaan Liechtenstein) or the dentin bonding agent SMP+ (Scotchbond Multi-Purpose Plus, 3M Dental Products, St. Paul MN) with Silux Plus or Z100 (3M Dental Products, St. Paul, MN). The samples were tested using a single plane lap shear bond strength test at 5 mm/min until failure. Statistical analysis was performed using ANOVA with Scheffe multiple comparison testing. Fracture surfaces of the debonded surfaces were examined using SEM to determine the failure mode of each specimen. Results: Bond strengths for the compomers were 12.7±2.9 MPa for Dyract and 8.9±4.1 MPa for Compoglass and were not significantly different. Bond strengths for the dentin bonded composites were significantly stronger than the compomer Compoglass, but were not different from one another, despite the use of different composites. The averages values for SMP+/Silux Plus and SMP+/Z100 were 15.7± 4.5 MPa and 15.2±5.6 MPa, respectively. SEM analysis showed that all materials exhibited mixed failure patterns. Compoglass specimens exhibited 5 of 11 failures classified as adhesive, while each of the other materials showed only 1 of 11 adhesive failures. Significance: Compomers have undergone rapid development over the last several years, but their bond strengths have not yet reached the same level as modern dentin bonded composites. Difference in composite filler type and amount had little influence on the bond strength determined in this work.

Pilot study of the effects of three bonding systems on the torsional resistance of a titanium-reinforced composite core

Statement of problem. There are no studies analyzing the effects of a bonding agent on torsional resistance for a titanium-reinforced core material bonded with a multistep bonding system. Purpose. This pilot study investigated the effects of multistep bonding agents on torsional resistance of a titanium-reinforced composite core material (Ti-Core core material). Material and methods. A total of 40 recently extracted human molars with their crowns removed were placed into acrylic resin blocks and divided into 4 groups of 10 specimens. Only multistep bonding systems were used (AllBond-2, ScotchBond Multi-Purpose, Tenure A&B, and the control without bonding agent). Specimens were prepared according to manufacturer’s instructions. The control group was etched with a 37.5% phosphate acid. All cores were fabricated with Ti-Core titanium core material with No. 1 hard copper bands as the matrix. Ti-Core core material was applied and allowed to cure for 1 hour, then the cores were placed in 100% humidity (water) for 1 week. Test specimens were placed in a special jig and a clockwise torsional force applied. Torsional force was measured on a Lebow 1102-200 torque transducer and recorded on a Hewlett Packard 7015B X-Y recorder in inch × ounce then converted into Newton-meter. One-way analysis of variance (ANOVA) was used to test for statistical significance ( P <.05). Results. Torsional values (Newton-meter) were AllBond-2, 0.1980, ScotchBond Multi-Purpose, 0.1890, Tenure A&B, 0.2142; the control group recorded a value of zero. Statistical analysis revealed that bonding systems did not differ from one another. Conclusion. Use of a bonding agent increased the core’s resistance to torsional forces. Lack of a bonding agent dramatically reduced the resistance to torque. (J Prosthet Dent 1999;82:277-80.)

Effect of dentin primers on the morphology, molecular composition and collagen conformation of acid-demineralized dentin in situ

Objectives: The purpose of this study was to assess the effect of two commercial primers and distilled water on the morphology, molecular composition and collagen conformation of acid-demineralized dentin in situ. Methods: Dentin specimens etched with Scotchbond Etchant were imaged by tapping mode AFM and analyzed by MIR-FTIR spectroscopy. They were then primed with Scotchbond Multi-Purpose Plus Primer, Scotchbond 1 Adhesive or distilled water and imaged and analyzed again. The chemical modifications induced on the uppermost 2 μm of primed dentin were studied after water and original primer subtraction. The conformational changes of type I collagen at this region were evaluated by deconvoluting the amide I band components. The absorbance ratio A n(1655/1627) was used to semiquantitatively assess, on a relative basis, the extent of collagen denaturation. Results: All the priming treatments swelled the collapsed dentin collagen left after etching. No evidence of primary bonding was found after priming treatments, while approximately 50% of the conditioned dentin collagen appeared denatured. Treatment with distilled water did not change the status of denatured collagen, however, application of the commercial primers refolded the α-helix to ≈95% of the extent found on the native reference dentin. Significance: The dynamic response of dentin collagen to demineralization and priming treatments reveals the critical role of some primers in rapidly restoring the conformational status of acid-denatured collagen. Implementation of reactive adhesive groups in α-helix recovery may provide an associative means of modifying the mechanical properties of the demineralized collagen based on the extent of their intermolecular bonding.

In vitro permeability and scanning electron microscopy study of acid-etched and ground enamel surfaces protected with dental adhesive coating.

Clinical procedures, such as acid etching and reshaping of the teeth supporting removable partial dentures by grinding off some enamel surface, increase the permeability of dental enamel. Teeth take several months in vivo to partially recover from such damage. In the meantime, the tooth is more susceptible to carious decay. To prevent this the ground or etched enamel should be effectively protected. Using electron paramagnetic resonance (EPR) and a two-chamber diffusion cell the authors studied the influence of adhesive resin applied to the ground and acid-etched enamel surfaces on the diffusion of spin label TMAPO (2,2,6-6 tetramethyl-4-acetamido-piperidine-1-oxyl) molecules through the enamel. The enamel permeability was measured in samples exposed to 1-min etching with 37% phosphoric acid, in samples etched for 5 min, and in samples ground with a diamond bur. Next, all the treated enamel surfaces were coated with Scotchbond Multi-Purpose Plus(R) dental adhesive system and the permeability measurements repeated. Scanning electron microscopy (SEM) was used to study the porosity of enamel surfaces. The adhesive resin film covering the etched or ground enamel surfaces was found to decrease significantly the diffusion through dental enamel. This finding confirms the clinical value of dental adhesives used to protect ground or accidentally acid-etched enamel surfaces. SEM analysis showed that adhesive resin covers the porous surface of the acid-etched and ground enamel tightly.

Comparative In Vitro Study of the Bond Strength of Composite to Enamel and Dentine Obtained with Laser Irradiation or Acid-etch

. The shear bond strength of composite resin on enamel and dentine was compared after acid-etch or irradiation by Er:YAG and Nd:YAP lasers. Forty-eight extracted molars were selected. Dentine and enamel samples were prepared by buccal and lingual surface sectioning to expose a plane enamel or dentine surface. Samples (n=12) were randomly assigned to eight groups. In groups 1 and 5, enamel and dentine surfaces were etched with a 37% phosphoric acid solution. In groups 2 and 6, surfaces were irradiated by Er:YAG laser at an energy of 200 mJ and 4 Hz for enamel and 140 mJ and 4 Hz for dentine. In groups 3 and 7, irradiation was performed by Nd:YAP laser at 310 mJ and 10 Hz for enamel and 240 mJ and 10 Hz for dentine. Groups 4 and 8 served as controls. A cone of composite was bonded perpendicularly onto the prepared surfaces using the Scotch Bond Multipurpose adhesive system. Each sample was then stored in physiological serum at 37°C for one week and thermocycled. Shear bond strength was determined on a universal testing machine. Composite–enamel and composite–dentine interfaces were examined by scanning electron microscopy and microanalysis. Shear bond strength was greater on dentine and enamel after acid-etch than laser radiation. These treatments could be ranged in the following order: acid-etch, laser Er:YAG and laser Nd:YAP. Differences between groups were significant for enamel, whereas no significant differences were found for dentine between acid-etch and Er:YAG laser-irradiation (Kruskal–Wallis test). Thus, laser preparation did not improve bonding to enamel and dentine.

Comparison of microleakage for three one-bottle and three multiple-step dentin bonding agents

Purpose. This in vitro study compared the ability of several recently introduced 1-bottle adhesives to their preceding multiple-step dentin bonding agents in reducing microleakage around Class V composite restorations. Material and methods. Facial and lingual Class V cavities were prepared in 48 molar teeth, which were randomly divided into 6 equal groups. Three groups used the fourth-generation multiple-step systems, and 3 used the fifth-generation single-bottle adhesives. All cavities were restored by composite and subjected to thermocycling and intermittent occlusal loading. After immersion in 0.5% basic fuchsin, the teeth were cut faciolingually in 5 consecutive sections and evaluated for dye penetration using a binocular stereomicroscope. Results. There was no statistically significant difference in the degree of microleakage comparing the adhesive’s generation and manufacturer and the location of the cavity margins. A significant interaction was found between margin location and manufacturer, which implied that the sealing capacity at the enamel and cementum margins was material-specific. Conclusion. Scotchbond Multi-Purpose and Single Bond adhesives provided the best seal for enamel margins, and One-Step and Optibond FL adhesives were best for cementum margins. (J Prosthet Dent 1999;82:209-13.)

Effect of moist vs. dry bonding to normal vs. caries-affected dentin with Scotchbond Multi-Purpose Plus.

Recent research in dentin bonding demonstrated the superiority of moist bonding over dry bonding on normal dentin, but it is unclear if this technique is also superior in bonding to caries-affected dentin. The purpose of this study was to evaluate the SEM appearance and bond strength of Scotchbond Multi-Purpose Plus (SMPP) to normal vs. caries-affected dentin bonded under moist vs. dry conditions, with and without polyalkenoic acid in the primer. Extracted carious human third molars were ground down by means of 600-grit SiC paper until the carious dentin no longer stained with caries detector solution. The flat surfaces were then primed, bonded, and built up with resin composite. After soaking in water for 1 day, the teeth were serially sectioned vertically into 5 or 6 slabs 0.7 mm thick. The bonded caries-affected areas were isolated by means of an ultrafine diamond bur to create an hourglass configuration with a cross-sectional area of 0.9 mm2. Bonded normal dentin was isolated the same way. Each specimen was attached to a Bencor device and tested in tension to failure. SMPP bonds to dry, normal dentin were only half as strong (21+/-10 MPa, x +/- SD) as those made to moist, normal dentin (42+/-9 MPa, p<0.01). There was no significant difference between bonds made to normal vs. caries-affected dentin by means of the moist technique (42+/-9 vs. 48+/-4 MPa, respectively). Removal of the polyalkenoic acid from the primer lowered (p<0.05) the bond strength of SMPP to caries-affected dentin (38+/-8 MPa). The benefits of moist bonding extend to caries-affected dentin. The polyalkenoic acid in the SMPP primer contributes to the high bond strength that can be achieved to caries-affected dentin.

Avaliação in vitro da força de união, através de teste de tração, de porcelana feldspática com diversos tratamentos superficiais à resina composta

Na busca da reprodução do aspecto dental, a porcelana se destaca entre os materiais restauradores. Desse modo, a utilização do material vem atualmente crescendo cada vez mais, e, com ela, a probabilidade de fraturas. Porém, uma falha nem sempre exige a troca da restauração: existe a possibilidade de um reparo com resina composta. Este trabalho se propôs a avaliar, in vitro, a força de união da resina composta à porcelana feldspática, quando efetuados os seguintes tratamentos superficiais na porcelana: asperização com instrumento cortante rotatório diamantado ou jateamento com óxido de alumínio de 50 micra, em aplicação isolada ou associada a condicionamento com ácido fosfórico, por 15 segundos, ou com ácido fluorídrico, por 1 ou por 4 minutos. Todos os espécimes foram previamente regularizados com lixa nº 220. Após os tratamentos superficiais, receberam o sistema de união adesivo para porcelana Scotchbond Multi-Purpose Plus Dental Adhesive System (3M). Feita a união com a resina composta (Restaurador Z100, 3M), foram armazenados em água destilada a 37ºC, em estufa, por 7 dias, e termociclados (600 ciclos de 1 minuto, entre 5 e 55ºC), sendo então submetidos a teste de tração. Pelos resultados obtidos, pôde-se concluir que ocorreu melhora na resistência à tração com todos os tratamentos propostos (em comparação ao observado no grupo controle, sem nenhum tratamento superficial). O jateamento produziu maior resistência de união que a asperização com instrumento cortante rotatório diamantado; mas, quando associados ao condicionamento com qualquer dos ácidos selecionados, independente do tempo de aplicação, não houve diferença estatística entre esses tratamentos.

Effects of three bonding systems on the torsional resistance of titanium-reinforced composite cores supported by two post designs

Statement of problem. There are no studies that have investigated the effects of bonding agents on the resistance to torque of a composite core supported by a prefabricated post. Purpose. This study investigated the ability of bonding agents to resist rational forces applied to titanium-reinforced composite cores supported by 2 post designs. Material and methods. Two post designs (AccessPost and ParaPost dowels) with titanium-reinforced core material and 4 bonding conditions (AllBond-2, ScotchBond Multi-Purpose, Tenure A&B, and without a bonding agent) were studied. A total of 80 specimens in 8 experimental groups were prepared and subjected to clockwise torsional forces until failure. Results. Torsional values ranged from 53.31 in. × oz (ParaPost/ScotchBond Multi-Purpose) to 72.31 in. × oz (AccessPost/ScotchBond Multi-Purpose). Two-way of analysis of variance failed to demonstrate a significant difference among posts or type of bonding system. Conclusion. The use of a multistep bonding agent had no significant effect on the torsional resistance of a core supported by a passive endodontic post. (J Prosthet Dent 1999;81:678-83.)

Dentin Bond Strength: Influence of Laser Irradiation, Acid Etching, and Hypermineralization

The purpose of the present study was to investigate the effects of ND:YLF laser irradiation (1.31 J/cm2; 250 mJ per pulse), acid etching, and hypermineralization on the shear bond strength (SBS) of the Scotchbond Multi-Purpose Plus (3M Dental Products) bonding system. Previous studies had shown that the pretreatment of the dentin substrate with laser irradiation can influence the SBS. Sixty bovine incisors were selected and stored at -18 degrees C. Dentinal buccal surface was exposed and radiographs were taken to control dentin thickness. The specimens were separated into 2 groups: (1) the control, which was kept in distilled water at 4 degrees C; (2) the hypermineralized, which was kept in hypermineralizing solution at 4 degrees C for 14 days. Each group was divided into 3 subgroups according to the type of dentin pretreatment used: M (acid etching + primer + bond); AL (acid etching + primer + bond + laser); and LA (laser + acid etching + primer + bond). A standard composite resin cylinder (Z100-3M) was bonded to the dentinal surface and the SBS performed on an Instron machine (500 Kg load cell at 0.5 mm/min), followed by scanning electron microscopy (SEM) and x-ray diffraction analysis. Analysis of variance (ANOVA) determined that the pretreatments influenced the SBS values (p < 0.05): AL (9.96 MPa), M (7.28 MPa), and LA (4.87 MPa). The interaction between the group and pretreatment factors also influenced the SBS (p < 0.05). The highest values were obtained for the interaction control/AL (11.64 MPa). The results suggested that dentin treatment with laser after the application of the adhesive system is efficient in achieving higher bond strength and is promising as a possible new adhesive substrate.

Influence of eugenol-containing temporary cement on efficacy of dentin-bonding systems.

Zinc oxide-eugenol (ZOE) cements are widely used as temporary filling materials. However, eugenol has earlier been shown to have a detrimental effect on both resin composites and dentin-bonding systems. The aim of the present in vitro study was to examine whether ZOE cement would also reduce the efficacy of relatively new dentin-bonding systems. This was done by determination of gap formation around resin composite fillings in dentin cavities and of bond strength of resin composite to enamel and dentin. The tooth surfaces involved were either freshly cut, or had been exposed to a ZOE cement (IRM) or to a non-ZOE cement (Cavit) for 7 d before application of a dentin-bonding system (Gluma CPS or Scotchbond Multi-Purpose Plus) and a resin composite (Z100). Gap formation was assessed in a light microscope on 20-min-old fillings and expressed as wall-to-wall contraction (the width of the maximum marginal gap in % of the cavity diameter). Bond strength was measured in shear on 1-d-old specimens. The mean values of wall-to-wall contraction were 0.06-0.09% with Scotchbond Multi-Purpose Plus and 0.20-0.24% with Gluma CPS. The mean values of bond strength to enamel were 22-25 MPa for Scotchbond Multi-Purpose Plus and 20-23 MPa for Gluma CPS, and to dentin were 20-22 MPa for Scotchbond Multi-Purpose Plus and 13-14 MPa for Gluma CPS. The use of Scotchbond Multi-Purpose Plus resulted in higher bond strength to dentin and less wall-to-wall contraction than did Gluma CPS. No differences were found in either wall-to-wall contraction or in bond strength between the three groups for either dentin-bonding system. Thus, the ZOE cement did not influence the efficacy of two relatively new dentin-bonding systems.