Microleakage of adhesively bonded cervical amalgam restorations

Purpose: To evaluate dye penetration in adhesively bonded cervical amalgam restorations. Materials and Methods: the specimens were randomly divided into four groups and the adhesives Prime & Bond 2. 1, Prime & Bond 2.1 Dual Cure, Scotchbond Multi Purpose Plus and Amalgambond Plus were tested. After being restored and polished, the teeth were thermocycled 1,000 times at temperatures varying between 5degreesC +/- 2degreesC and 55degreesC +/- 2degreesC. Statistical analysis was carried out using the Kruskal-Wallis test and multiple comparisons. Results: Scotchbond Multi-Purpose Plus demonstrated lower levels of microleakage in enamel and dentin. The dual adhesives were more effective than the one bottle adhesive.

Human pulpal response to direct pulp capping with an adhesive system

Purpose: To evaluate clinically and microscopically the human pulp response when directly capped with an adhesive system or calcium hydroxide over short (9-12 days) and long (53-204 days) experimental periods. Materials and Methods: Fifty-one sound human premolars scheduled for orthodontic extraction, had their pulp horns gently exposed with a diamond point. Debris in the pulp wound was washed out with a sterile saline solution. The pulps were then capped with either an adhesive system (Scotchbond Multi-Purpose Plus) or calcium hydroxide. All teeth were subsequently restored with resin-based composite (Z-100) according to the manufacturer's instructions. After the experimental periods, the teeth were extracted and processed for light microscopic examination. Results: Short-term: the pulp tissue capped with SBMP-P exhibited dilated and congested blood vessels associated with a mo;derate inflammatory response and blanching of pulp cell nuclei. Long-term: no evidence of healing and bridge formation was observed. A persistent mild inflammatory pulp response was present. Micro-abscesses were detected in three cases associated with bacterial infiltration. Calcium hydroxide stimulated early pulp repair and dentin bridging which extended into the longest period.

Shear Bond Strength of Different Repair Systems to Titanium After Water Aging

This study evaluated the shear bond strength (SBS) and stability of commercially pure titanium (CP Ti)/repair material interfaces promoted by different repair systems. One hundred CP Ti cast discs were divided into five repair system groups: 1) Epricord (EP); 2) Bistite 11 DC (BT); 3) Cojet (CJ); 4) Scotchbond Multi-Purpose Plus (SB) (control group); and 5) Cojet Sand plus Scotchbond Multi-Purpose Plus (CJSB). The specimens were stored in distilled water for 24 hours at 37 degrees C, thermal cycled (5000 cycles, 5 degrees-55 degrees C) and stored under the same conditions for either 24 hours or six months (n=10). SBS was tested and the data were analyzed by two-way analysis of variance (ANOVA) and Tukey test (alpha=.05). Failure mode was determined with a stereomicroscope (20x). The repair system, storage time, and their interaction significantly affected the SBS (p<0.001). At 24 hours, CJSB exhibited the highest SBS value, followed by CJ. At six months, these two groups had similar mean SBS (p>0.05) and higher means in comparison to the other groups. For both storage times, BT presented the lowest SBS, while the EP and SB groups did not differ significantly from one another (p>0.05). There were no significant differences in SBS between the storage times for the groups EP and CJ (p>0.05). The groups BT, SB, and CJSB showed 100% adhesive failure, irrespective of storage time. The CJSB group showed the highest SBS at both storage times. At six months, the CJ group exhibited a similar SBS mean value when compared to the CJSB group. Water storage adversely affected the groups BT, SB (control group), and CJSB. Considering SBS values, stability, and the failure mode simultaneously, the CJ group showed the best CP Ti repair performance.

Evaluation of marginal microleakage in Class II cavities: Effect of microhylolrid, flowable, and compactable resins

Objective: the goal of the present study was to evaluate the microleakage on the cementum/dentin and enamel surfaces in Class 11 restorations, using different kinds of resin composite (microhybrid, flowable, and compactable). Method and materials: Forty human caries-free molars were extracted and selected. Eighty Class 11 standardized cavities were made in the cervical wall at the cementoenamel junction (CEJ) and at the mesial and distal surfaces. The teeth were divided into four groups: G1 - adhesive system + microhybrid resin composite Z100; G2 - adhesive system + compactable resin composite Prodigy Condensable; G3 - adhesive system + flowable resin composite Revolution + Z1 00 resin composite; G4 - adhesive system + Revolution fluid resin + compactable resin composite Prodigy Condensable. The adhesive system used in this study was Scotchbond Multi-Purpose Plus. The specimens were thermocycled in baths of 5degreesC and 55degreesC for 1,000 cycles and immersed in 50% silver nitrate solution. The specimens then were sectioned and evaluated on degree of dye penetration. Results: the results were evaluated using the nonparametric Kruskall-Wallis test, which showed a statistically significant difference between groups G1 and G4, G2 and G4, and G3 and G4. Conclusions: None of the materials was able to eliminate the marginal microleakage at the cervical wall; the application of a low-viscosity resin composite combined with a compactable resin composite significantly decreased the microleakage.

Does Adhesive Resin Application Contribute to Resin Bond Durability on Etched and Silanized Feldspathic Ceramic?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dentin bond strength: Influence of laser irradiation, acid etching, and hypermineralization

Objective: the purpose of the present study was to investigate the effects of ND:YLF laser irradiation (1.31 J/cm(2); 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. Summary Background Data: Previous studies had shown that the pretreatment of the dentin substrate with laser irradiation can influence the SBS, Methods: 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. Results: 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), Conclusion: 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.

Effects of Resinous Monomers Used in Restorative Dental Modeling on the Cohesive Strength of Composite Resin

Purpose: The purpose of this study was to evaluate the cohesive strength of the composite using different resinous monomers to lubricate instruments used in the Restorative Dental Modeling Insertion Technique (RDMIT).Materials and Methods: The composite specimens were made by using a prefabricated Teflon device. Different resinous monomers were used at the interface to lubricate the instruments, for a total of 72 specimens divided into 6 groups: 1. control group, no resinous monomer was used; 2. Composite Wetting Resin; 3. C & B Liquid; 4. Scotchbond Multi-Purpose Adhesive; 4. Adper Single Bond Adhesive; 6. Prime & Bond NT. Specimens were submitted to the circular area tensile test to evaluate the cohesive strength at the composite interfaces. Data were analyzed using ANOVA and Tukey's test (alpha = 0.05).Results: ANOVA showed a value of p < 0.0001, which indicated that there were significant differences among the groups. The means (SD) for the different groups were: Adper Single Bond Adhesive: 26 (12) a; control group: 28 (3) ab; Prime & Bond NT: 32 (12) ab; Composite Wetting Resin: 36 (9) abc; C&B Liquid: 38 (7) bc; Scotchbond Multi-Purpose Adhesive: 46 (10) c. Groups denoted with the same letters were not significantly different. Only Scotchbond Multi-Purpose Adhesive, used for direct restorations, had a statistically significantly higher bond strength than the control group, Adper Single Bond Adhesive, and Prime & Bond NT. Adper Single Bond with Adhesive showed a statistically significantly lower mean value than C & B Liquid.Conclusion: The results of this study indicate that the resinous monomers used for lubricating the instruments in the RDMIT did not alter the mechanical properties of the composite, and therefore did not reduce the cohesive bond strength at the composite interfaces.

Microleakage of hydrophilic adhesive systems in Class V composite restorations

Purpose: To investigate the microleakage of four hydrophilic adhesive systems: one multiple-bottles (Scotchbond Multi-Purpose Plus); two one-bottle (Single Bond, Stae); and one self-etching (Etch & Prime 3.0). Materials and Methods: 120 bovine incisor teeth were divided into four groups (n = 30) and Class V cavities were prepared at the cemento-enamel junction. The cavities were restored with the adhesive systems and with Z100 composite. The teeth were thermocycled 1,000 times between 5 +/- 2 degreesC and 55 +/- 2 degreesC with a dwell time of 1 min, and then placed in a 2% methylene blue dye (pH 7.0) for 4 hrs, washed and sectioned vertically through the center of the restorations. The qualitative evaluation was made by three examiners who distributed pre-established scores (0-4) for each tooth using a stereomicroscope at x30 magnification. Results: In enamel margins little microleakage was observed and the Kruskal-Wallis analysis did not show differences. In dentin margins the KruskaI-Wallis and multiple comparison analyses were applied: microleakage was significantly greater with Stae (median 3) and Scotchbond MP Plus (median 4). Single Bond (median 1) and Etch & Prime 3.0 (median 2) showed the best results in dentin margins, and the statistical analysis did not demonstrate differences in microleakage among these groups.

An In Vitro Comparison of Different Cementation Strategies on the Pull-out Strength of a Glass Fiber Post

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fiber Post Cementation Strategies: Effect of Mechanical Cycling on Push-out Bond Strength and Cement Polymerization Stress

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Microleakage in primary teeth restored by conventional or bonded amalgam technique.

The aim of this in vitro study was to evaluate marginal leakage in class V restorations in primary teeth restored with amalgam, using three different techniques. Thirty maxillary anterior primary teeth, clinically sound and naturally exfoliated, were used. In group 1 (n = 10), two thin layers of a copal varnish (Cavitine) were applied. In group 2 (n = 10), Scotchbond Multi-Purpose Plus, a dual adhesive system, was used according to manufacturer instructions. In group 3 (n = 10), One-Step adhesive system in combination with a low-viscosity resin (Resinomer) were used according to manufacturer instructions. All samples were restored with a high-copper dental amalgam alloy (GS 80, SDI). After restoration, the samples were stored in normal saline at 37 degrees C for 72 h. The specimens were polished, thermocycled (500 cycles, 5 degrees and 55 degrees C, 30-s dwell time) and impermeabilized with fingernail polish to within 1.0 mm of the restoration margins. The teeth were then placed in 0.5% methylene blue for 4 h. Finally, the samples were sectioned and evaluated for marginal leakage. The Kruskal-Wallis test showed that the filled adhesive resin (group 3) had the least microleakage. There was no significant difference between groups 1 and 2.

Evaluation of marginal microleakage in Class II cavities: Effect of microhybrid, flowable, and compactable resins

Objective: The goal of the present study was to evaluate the microleakage on the cementum/dentin and enamel surfaces in Class II restorations, using different kinds of resin composite (microhybrid, flowable, and compactable). Method and materials: Forty human caries-free molars were extracted and selected. Eighty Class II standardized cavities were made in the cervical wall at the cementoenamel junction (CEJ) and at the mesial and distal surfaces. The teeth were divided into four groups: G1 - adhesive system + microhybrid resin composite Z100; G2 - adhesive system + compactable resin composite Prodigy Condensable; G3 - adhesive system + flowable resin composite Revolution + Z100 resin composite; G4 - adhesive system + Revolution fluid resin + compactable resin composite Prodigy Condensable. The adhesive system used in this study was Scotchbond Multi-Purpose Plus. The specimens were thermocycled in baths of 5°C and 55°C for 1,000 cycles and immersed in 50% silver nitrate solution. The specimens then were sectioned and evaluated on degree of dye penetration. Results: The results were evaluated using the nonparametric Kruskall-Wallis test, which showed a statistically significant difference between groups G1 and G4, G2 and G4, and G3 and G4. Conclusions: None of the materials was able to eliminate the marginal microleakage at the cervical wall; the application of a low-viscosity resin composite combined with a compactable resin composite significantly decreased the microleakage.

The effect of adhesive systems on the pullout strength of a fiberglass-reinforced composite post system in bovine teeth

Purpose: To evaluate the pullout strength of a glass fiber-reinforced composite post (glass FRC) cemented with three different adhesive systems and one resin cement. The null hypothesis was that pullout strengths yielded by the adhesive systems are similar. Materials and Methods: Thirty bovine teeth were selected. The size of the specimens was standardized at 16 mm by sectioning off the coronal portion and part of the root. The specimens were divided into three groups, according to the adhesive system, which were applied following the manufacturers' instructions: G1, ScotchBond Multi-Purpose Plus; G2, Single Bond; G3, Tyrian SPE/One-Step Plus. The glass FRCs (Reforpost) were etched with 37% H3PO4 for 1 min and silanized (Porcelain Primer). Thereafter, they were cemented with the dual resin cement En-Force. The specimens were stored for 24 h, attached to an adapted device, and submitted to the pullout test in a universal testing machine (1 mm/min). The data were submitted to the one-way ANOVA and Tukey's test (α = 0.05). Results: G1 (30.2 ± 5.8 Kgf) displayed the highest pullout strength (p < 0.001) when compared to G2 (18.6 ± 5.8 Kgf) and G3 (14.3 ± 5.8 Kgf), which were statistically similar. Analysis of the specimens revealed that all failures occurred between the adhesive system and the root dentin (pullout of the post cement), regardless of group. Conclusion: The multiple-bottle, total-etch adhesive system provided higher pullout strength of the glass FRC when compared to the single-bottle, total-etch, and single-step self-etching adhesive systems. The null hypothesis was rejected (p < 0.001).

Regional hydroclimatic variability and Brazil's 2001 energy crisis

Purpose - This paper seeks to address the issue of persistent and widespread drought conditions during 2000 and 2001, which were the apparent cause of the decline of water levels in the reservoirs of Brazilian hydroelectric power plants. Design/methodology/approach - This issue is addressed here through a case study of the hydroclimatology of the Paraíba river basin, in Southeast Brazil, home to four large multi-purpose operational reservoirs. Findings - The data analysis shows that neither changes in the frequency nor magnitude of extreme hydrological events (droughts and floods) nor in annual rainfall amounts can be detected from the existing climate record. The explanation is consistent with the fact that the terrestrial water and energy cycles are tightly, and non-linearly, coupled through evapotranspiration. Research limitations/implications - Therefore small change in the seasonality of rainfall can have a significant impact on the basin's overall hydrologic regime, and thus on the availability of water resources. Originality/value - Often, adaptation and resilience to climate variability are discussed in the context of catastrophic events such as floods and droughts. This study suggests that a different type of impacts, those associated with subtle, yet persistent changes of seasonality in the terrestrial water cycle, cannot be ignored in studies of long-term sustainability of water resources. © Emerald Group Publishing Limited.

Resin bonding to root canal dentin: Effect of the application of an experimental hydrophobic resin coating after an all-in-one adhesive

Aim: Based on the hypothesis the application of a low-viscosity hydrophobic resin coating improves the bond of all-in-one adhesive, the purpose of the study was to evaluate the bond strength of four adhesive systems to bovine root dentin using the push-out test method. Methods and Materials: The root canals of 32 bovine roots (16 mm) were prepared to a length of 12 mm using a FRC Postec Plus preparation drill. The specimens were allocated into four groups according to the adhesive system used: (Group 1) All-in-one Xeno III; (Group 2) All-in-one Xeno III+ScotchBond Multi-Purpose Plus Adhesive; (Group 3) Simplified Etch & Rinse One Step Plus; and (Group 4) Multi-Bottle Etch & Rinse All-Bond 2. A fiber-reinforced composite retention post was reproduced using an additional silicon impression and fabricated with DuoLink resin cement. The root specimens were treated with the selected adhesive systems, and the resin posts were luted in the canals with DuoLink resin cement. Each root specimen was cross sectioned into four samples (±1.8 mm in thickness), and the post sections were pushed-out to determine the bond strength to dentin. Results: Group 2 (2.9±1.2) was statistically higher than Group 1 (1.1±0.5) and Group 3 (1.1±0.5). Groups 1 and 3 showed no statistically significant difference while Group 4 (2.0±0.7) presented similar values (p>0.05) to Groups 1, 2, and 3 [(one-way analysis of variance (ANOVA)] and Tukey test, α=0.05). Conclusion: The hypothesis was accepted since the application of the additional layer of a low-viscosity bonding resin improved the bond of the all-in-one adhesive. Further studies must be conducted to evaluate the long-term bond.