Doctor-patient care relationship in genetic cardiomyopathies: An exploratory study on clinical consultations.

BACKGROUND: The present study aims to explore the setting of consultation and communication between physicians and patients affected by genetic cardiomyopathies, investigating how the two parts of the therapeutic relationship participate and share information. METHODS AND RESULTS: 45 adult patients affected by various cardiomyopathies took part in a prospective case study while attending consultations at a cardiologic outpatient clinic constituting an Italian referral centre for cardiomyopathies. A researcher observed the consultations, which were audio-recorded and transcribed. Transcripts were coded and an analysis of setting, type of communication implemented and participation of doctors and patients in terms of word-count and type of questions/answers was carried out. Overall word-count was significantly higher for physicians than for patients (t(44) = 9,506; p<0.001). Doctors were prone to ask closed questions (t(44) = -11,90; p<0.001) while patients preferred open answers (t(44) = 5.58; p<0.001), enriched with subjective issues related to their illness experience. Partial correlation highlights a significant positive relation between doctors' closed question and patients' open answers (r = .838; p<0.001). CONCLUSIONS: Findings emphasize patients' need for adequate time and space to share their subjective illness experience with the physician, within an approach informed by the insights and recommendations of Narrative Medicine. These findings are instrumental to improving the specific clinical setting for individuals with genetic cardiomyopathies.

Pathogens of wild maned wolves (Chrysocyon brachyurus) in Brazil.

The maned wolf, Chrysocyon brachyurus, is an endangered Neotropical canid that survives at low population densities. Diseases are a potential threat for its conservation but to date have been poorly studied. We performed clinical evaluations and investigated the presence of infectious diseases through serology and coprologic tests on maned wolves from Galheiro Natural Private Reserve, Perdizes City, Minas Gerais State, southeastern Brazil. Fifteen wolves were captured between 2003 and 2008. We found high prevalences of antibody to canine distemper virus (CDV; 13/14), canine parvovirus (CPV; 4/14), canine adenovirus type 2 (13/14), canine coronavirus (5/11), canine parainfluenza virus (5/5), and Toxoplasma gondii (6/8), along with Ancylostomidae eggs in all feces samples. Antibodies against Leishmania sp. were found in one of 10 maned wolves, and all samples were negative for Neospora caninum. Evidence of high exposure to these viral agents was also observed in unvaccinated domestic dogs from neighboring farms. High prevalence of viral agents and parasites such as CDV, CPV, and Ancylostomidae indicates that this population faces considerable risk of outbreaks and chronic debilitating parasites. This is the first report of exposure to canine parainfluenza virus in Neotropical free-ranging wild canids. Our findings highlight that canine pathogens pose a serious hazard to the viability of maned wolves and other wild carnivore populations in the area and emphasize the need for monitoring and protecting wildlife health in remaining fragments of the Cerrado biome.

Push-out bond strength of circular and oval-shaped fiber posts.

This study aimed at evaluating the post-root dentin push-out bond strength of circular and oval posts luted in oval-shaped canals with two different resin cements. Twenty extracted premolars with oval-shaped canals were selected, endodontically instrumented and obturated. The teeth were divided into two groups according to the drill used for post-space preparation and to the post shape (Ellipson oval tip + post and MTwoPF + DT Light-Post). Each group was then subdivided into two subgroups according to the cement (Gradia Core and Corecem Automix). The post-dentin bond strength was evaluated with the thin-slice push-out test. The bonded surface area was calculated for each post shape with an appropriate geometric formula in order to express the retentive strength in megapascal. Push-out strength data were analyzed with the Kruskal-Wallis ANOVA. The results showed that neither the drill-post system nor the cement significantly affected the push-out strength. The means (SD) of the push-out bond strengths in the experimental subgroups were the following: 11.79 MPa (4.77) for Gradia Core/Ellipson tip and post, 13.36 MPa (5.16) for Gradia Core/MtwoPF and DT Light-Post, 11.18 MPa (2.58) for Corecem Automix/Ellipson tip and post, and 10.91 MPa (3.89) for Corecem Automix/MtwoPF and DT Light-Post. In conclusion, circular and oval posts achieved similar retentive strengths in oval canals.

Influence of ultrasound application on inlays luting with self-adhesive resin cements.

The study was aimed at assessing the influence of the cement manipulation and ultrasounds application on the bonding potential of self-adhesive resin cements to dentin by microtensile bond strength testing and microscopic observations of the interface. Fifty-six standardized mesio-occlusal class II cavities were prepared in extracted third molars. Class II inlays were made using the nano-hybrid resin composite Gradia Forte (GC Corp, Tokyo, Japan), following the manufacturer's instruction. The sample was randomly divided into two groups (n = 28) according to the luting technique. Half of the specimens were luted under a static seating pressure (P), while the other ones were cemented under vibration (V). The inlays were luted using the following self-adhesive resin cements: G-Cem (G, GC Corp., Tokyo, Japan) Automix (GA) and Capsule (GC); RelyX Unicem (RU, 3 M ESPE, Seefeld, Germany) Clicker (RUC) and Aplicap (RUA). Microtensile sticks and specimens for scanning electron microscope (SEM) observations were obtained from the luted teeth. The interfacial strengths measured for the cements under static pressure or ultrasonic vibration were [median (interquartile range)]: GC/V 4 (2.3-7.9); GC/P 6.8 (4.1-10.1); GA/V 3 (1.9-6.7); GA/P 1.9 (0-5.1); RUC/V 6.6 (4.6-9.8); RUC/P 4.1 (1.8-6.4); RUA/V 6.2 (2.4-10.4); RUA/P 3.4 (0-5.4). The cement formulation influenced dentin bond strength of G. RU bond strength was affected by the luting technique. SEM analysis revealed a homogeneous structure and reduced porosities for both cements as a result of ultrasonic vibration. RU benefited from the application of ultrasounds, while GC achieved higher bond strengths than GA.

Influence of resin composite mechanical properties on adhesive microtensile bond strength to dentin.

PURPOSE: To determine the influence of mechanical properties of resin-based composites on the microtensile bond strength to dentin of all-in-one adhesives. MATERIALS AND METHODS: Microtensile bond strengths were measured with the non-trimming technique for the experimental groups: 1) Bond Force/Estelite Σ (Tokuyama); 2) G-Bond Plus (GC)/Estelite Σ; 3) Bond Force/Gradia Direct Anterior (GC);4) G-Bond Plus/Gradia Direct Anterior; 5) Bond Force/Gradia Direct LoFlo (GC); 6) G-Bond Plus/Gradia Direct LoFlo. The following mechanical properties of the resin-based composites were assessed: tensile strength, flexural strength, tensile elastic modulus, shear elastic modulus, Poisson's ratio, Vicker's hardness, contraction stress. Three-dimensional models of microtensile beams were created for finite element analysis of the first principal stress values and distribution in the adhesive layer during microtensile testing. Statistical tests were applied to microtensile bond strength values (two-way ANOVA) and to data from mechanical tests (one-way ANOVA). In all the analyses, the level of significance was set at p < 0.05. RESULTS: While the adhesive did not significantly influence microtensile bond strength, the composite was a significant factor. Regardless of the adhesive, Estelite Σ yielded significantly higher bond strengths than Gradia Direct Anterior and Gradia Direct LoFlo, that were comparable. Adhesive-composite interactions were not statistically significant. Estelite Σ had the highest Vicker's hardness, the highest tensile and shear elastic moduli, the lowest and closest to dentin Poisson's ratio. A more favorable stress distribution in the adhesive layer occurred in the Estelite Σ model. CONCLUSIONS: When comparing the bonding potential of several adhesives with the microtensile technique, the same resin composite should be used in all the experimental groups for building up the coronal portion.

Influence of ozone on the composite-to-composite bond.

The study evaluated the effect of ozone application on the composite-to-composite bond. Three hundred and twenty cylindrical composite specimens were divided into two groups: group 1 was subjected to a 60 s ozone application, whereas group 2 remained untreated. Four subgroups were obtained from each group according to the intermediate repair agent: an adhesive, a silane, silane/adhesive combination, or flowable composite. Repair composite cylinders were built-up. The composite repair strength was tested after 24 h and after thermocycling with a shear test. Additionally, 4 mm × 4 mm × 2 mm composite specimens were prepared and stored 24 h in deionized water. Half of the specimens were subjected to ozone application and the other served as control. The elastic modulus (E) and the Vicker's hardness (VH) of the composite surfaces were tested immediately and after thermocycling. Significant differences among the experimental groups were detected (p < 0.001). The composite repair strength was affected by the pretreatment and by the intermediate agent, whereas, the thermocycling was not significant. The partial eta-squared statistics showed that the intermediate agent was the main factor affecting the composite repair strength, whereas the pretreatment played a minor role. No differences were observed between ozone and control groups when the same intermediate agent and the same aging conditions were applied. Repairing with flowable composite tended to achieve higher bond strengths (20.7 and 26.5 MPa in ozone and control groups, respectively, after 24 h). The use of silane coupling agent showed the lowest composite repair strengths. Ozone did not affect E and VH (p > 0.05) and the thermocycling affected only E (p < 0.05). In conclusion, the application of ozone does not impair the composite-to-composite bond.

Influence of ozone application on the repair strength of silorane-based and ormocer-based composites.

PURPOSE: To evaluate the effect of gasiform ozone on the repair strength of ormocer-based and silorane-based composites. METHODS: 160 cavities were created in methacrylate cylinders. Half of the cavities were filled with a silorane-based composite, whereas the other half was filled with an ormocer-based composite. After storage (1 week, deionized water, 37 degrees C) the specimens of each restorative material were divided into two main experimental groups: in Group 1 the specimens were subjected to a 60-second ozone gas application; in Group 2 no pretreatment was performed (control). The corresponding adhesive of each restorative material was applied as the intermediate repair agent in both groups. Repair cylinders were then built up with the homologous material. Half of the specimens in each group were subjected to thermocycling (5,000 cycles, 5 degrees C-55 degrees C, dwell time 30 seconds, transfer time 5 seconds) prior to testing, whereas the other specimens were immediately tested. The repair strength was assessed with a shear test. The two-way ANOVA with pretreatment and thermocycling as the main factors was used to analyze the shear bond strength data within each restorative material. RESULTS: The pretreatment, the thermocycling and their interaction did not significantly affect the repair strength of either tested materials (P > 0.05). The ozone treatment did not significantly affect the repair strength. The silorane-based composite showed lower repair strengths compared to those of the ormocer-based composite. The immediate repair strengths in the ozone-treated and control groups were respectively, 28.1 (13.8) MPa and 28.8 (8.8) MPa for the silorane-based composite and 31.5 (9.3) MPa and 35.6 (10.6) MPa for the ormocer-based composite. After thermocycling, the repair strengths in the ozone-treated and control groups were 27.7 (9.7) MPa and 29.5 (11.1 ) MPa for the silorane-based composite and 31.4 (6.0) MPa and 34.2 (4.5) MPa for the ormocer-based composite. Mixed failures occurred most frequently in all experimental groups. In conclusion, ozone did not affect the repair strength of the tested silorane-based and ormocer-based composites.

Evaluation of the mechanical properties of dental adhesives and glass-ionomer cements.

Adhesives and lining/base materials should relieve the stresses concentrated at the tooth/restoration interface. The study aimed at comparing the mechanical properties of eight adhesives and six glass-ionomer cements (GICs). The adhesives were applied on dentin disks, whereas 2 mm x 3 mm x 2 mm GICs specimens were prepared in a teflon mold. Vicker's hardness (VH), elastic modulus (E), creep (Cr) and elastic work (We/Wtot) were measured with a micro hardness indenter. One-way ANOVA and Tukey's test were used to compare the mechanical properties within each materials' type and among the materials' classes. Enamel and dentin were used as references. Significant differences were detected within each materials' type and among the materials' classes and enamel and dentin. GICs were superior to adhesives in VH and E and showed a VH similar to dentin. GICs presented mechanical properties more similar to enamel and dentin than adhesives.

First observations of nest attendance behavior by wild maned wolves, Chrysocyon brachyurus.

In many species of canids the male's role in reproduction extends to providing extensive or some parental care to his offspring. Maned wolves are a monogamous canid species whose males have been observed providing parental care to their offspring in captivity, but no field observations exist. We observed a wild pair of maned wolves at their nest site in a period soon after the female had given birth for a total period of 65 days. We made five observation sessions with an average of 3-4 days each separated by approximately 2 weeks. Direct visual observations of maned wolves were made each 30 min during the hours of darkness (17:00-07:00) using night-vision binoculars and confirmed by VHF radiotelemetry. During observations we recorded the location of the male and the female in relation to the nest (i.e., in the nest, nearby or long way from the nest). The results showed that the female spent more than 60.44% of her time in or near the nest. The male spent 28.90% of his time in or near the nest. There was a positive significant correlation between the female and the male in terms of the amount of time spent in or near the nest (P<0.01). The maned wolves showed a strong temporal variation in time spent in or near the nest. In conclusion, our data show that wild male maned wolves--probably--provide parental care through provision of food to their female and presumed offspring rather than "babysitting."

Light transmission through fiber post: the effect on adhesion, elastic modulus and hardness of dual-cure resin cement.

OBJECTIVES: The aim of this study was to investigate the effect of fiber post light transmitting ability to the continuity of resin cement-root dentin (C-RD) and resin cement-fiber post (C-FP) interface, elastic modulus and hardness of a dual-cure resin cement. METHODS: Spectrophotometric measurements were applied for the determination of light transmission at coronal, middle and apical level as well as at the apical tip through Tech 21 X-OP (TECH) and DT Light Post (DT). Posts were cemented using dual-cured resin cement (Calibra). Roots were sectioned longitudinally through the post. Epoxy resin replicas were made and used to evaluate C-RD and C-FP interface under SEM. Modulus of elasticity (E) and Vicker's hardness (VH) of the cement layer were assessed. RESULTS: No light transmission was detected through TECH. Light transmission through DT decreased from coronal to apical and rose at the apical tip. TECH presented a significantly lower percentage of continuous C-RD and C-FP interface in comparison to DT. Coronal third of C-RD interface in TECH specimens had a significantly higher percentage of continuity than apical third. No regional differences in continuity of C-RD interface were found in DT specimens. E and VH were significantly lower when TECH was used, and decreased from coronal to apical for both posts. SIGNIFICANCE: Cementation of fiber post with no light transmitting ability using a dual-cured resin cement resulted in lower E and VH of the cement layer, and lower percentage of continuous C-RD and C-FP interface in comparison to cementation of light transmitting fiber post.

Resin cement thickness in oval-shaped canals: oval vs. circular fiber posts in combination with different tips/drills for post space preparation.

PURPOSE: To evaluate the cement thickness around oval and circular posts luted in oval post spaces prepared with different drills/tips. METHODS: Extracted premolars were endodontically treated and obturated, then randomly divided into three groups (n = 5) according to the tips/drills used for post-space preparation and to the type of fiber post luted: medium grit oval tip + oval posts, fine grit oval tip + oval posts, Mtwo Post File drill + circular posts. The specimens were sectioned in horizontal slices; one slice per canal third was chosen for each post-space, resulting in three slices for each specimen. The distances between the canal wall and the post perimeter were measured on SEM images of each slice. RESULTS: The fine grit tip + oval post group obtained statistically significant lower cement thicknesses than the other groups (P < 0.05), in particular in the apical third. The MtwoPF + circular post group showed the highest cement thickness, comparable to that of the medium tip + oval post group. A good post fitting in oval-shaped canals can be obtained using a fine grit oval tip combined with oval posts.

SEM and microleakage evaluation of the marginal integrity of two types of class V restorations with or without the use of a light-curable coating material and of polishing.

OBJECTIVES: To evaluate the marginal integrity of class V restorations through an SEM observation and a microleakage test. METHODS: Teeth with class V cavities were restored with either a flowable composite (n=20) or a glass ionomer cement (GIC) (n=20). Ten restorations in each group were immediately polished. A coating agent was applied on five polished and five non-polished restorations of each group. No coating was used on the remaining specimens. Epoxy resin replicas of the restorations were observed under a SEM and the percentage of marginal gaps was calculated. After immersion in a 2% methylene blue solution, three sections were obtained from each specimen and observed under a stereomicroscope. Occlusal and gingival microleakage were evaluated with a four-steps scoring system. The percentages of marginal gaps and the microleakage scores were analyzed with the Kruskal-Wallis ANOVA and the Mann-Whitney test with Bonferroni's correction. Occlusal and gingival microleakage were compared with the Wilcoxon test. RESULTS: No gaps were detected after coating. The restorative materials did not differ in interfacial gaps. Immediate polishing increased the gaps of uncoated restorations (p<0.05). The microleakage decreased with coating, except for occlusal wall of polished flowable composite restorations. After coating, the occlusal microleakage was higher than the gingival (p<0.05), except for non-polished flowable composite restorations. After polishing and coating, the flowable composite showed higher occlusal microleakage than the GIC. The polishing increased the occlusal microleakage of coated flowable composite restorations. CONCLUSIONS: The coating procedure is advisable for restoring marginal integrity and reducing gingival microleakage in class V restorations.

How can droplet formation occur in endodontically treated teeth during bonding procedures?

PURPOSE: The aim of this in vivo study was to clarify how blistering formation occurs along intraradicular dentin bonded interfaces. MATERIALS AND METHODS: Patients were selected and post space was prepared in vivo in endodontically treated teeth. Post space was etched, dried with ethanol, and bonded with one of the following adhesive systems: All Bond 2, XP-Bond, Clearfil SE Bond, Xeno III. The four adhesives were considered as representative of each bonding system class. An additional group was prepared with phosphoric acid treatment + application of Pre-Bond unfilled resin of All Bond 2, without the use of the primer agent. Etching was avoided for self-etching materials. Replicas of the post space were taken (1) after post space preparation; (2) after etching, rinsing, and drying; (3) after ethanol drying, and (4) after adhesive application. Replicas were analyzed with SEM and blisters were counted by independent observers. Statistical analysis was performed with Kruskal-Wallis ANOVA and Dunn's multiple comparison tests at p = 0.05. RESULTS: No blister formation occurred on replicas taken prior to adhesive application, while blister formation was evident in all replicas of bonded interfaces, irrespective of the adhesive system. No statistical difference in the number of droplets was found between All Bond 2, XP-Bond, and Clearfil SE Bond. Xeno III exhibited the highest number of blisters. Specimens bonded with Pre-Bond unfilled resin of All Bond 2 without primer application showed no blister formation. CONCLUSION: This study revealed that blister formation occurs only if the priming agent of the adhesive system was applied, thus supporting the hypothesis that blistering occurs due to adhesive phase separation or insufficient solvent evaporation.

Effect of curing modes of dual-curing luting systems and root regions on retention of translucent fiber posts in root canals.

PURPOSE: To evaluate the effect of different curing modes of dual-curing luting systems and root regions on the push-out strength of fiber posts to intraradicular dentin. MATERIALS AND METHODS: Forty-two extracted premolars with a single root canal were sectioned at the cementoenamel junction and the roots were endodontically treated. The roots were divided into two groups according to two dual-curing luting systems: (1) XP BOND-Dual Cure/Calibra resin cement; (2) XP BOND-Dual Cure/FluoroCore 2. For each luting system, three different curing modes were applied to the dentin adhesive and resin cement: "Self-cure and Self-cure (SC&SC)", "Self-cure and Dual-cure (SC&DC)", and "Dual-cure and Dual-cure (DC&DC)". Translucent Easy fiber posts (Dentsply Maillefer) were luted in the roots. A thin-slice push-out test was performed, and the data of push-out strength were analyzed using three-way ANOVA with luting system, curing mode, and root region (apical, middle and coronal) as factors. Tukey's test was used for post-hoc comparisons. RESULTS: The push-out strength of XP BOND-Dual Cure/Calibra was significantly lower when Calibra resin cement was self-cured than when it was dual-cured (SC&SC: 6.04 +/- 2.65 MPa; SC&DC: 10.69 +/- 3.01 MPa; DC&DC: 10.72 +/- 3.63 MPa; p < 0.05). The curing modes did not affect the push-out strength of XP BOND-Dual Cure/FluoroCore 2 (SC&SC: 7.90 +/- 3.94 MPa; SC&DC: 8.32 +/- 2.73 MPa; DC&DC: 9.27 +/- 4.12 MPa; p > 0.05). The coronal push-out strength was significantly higher than the apical push-out strength (p < 0.05). CONCLUSION: Retention of fiber posts in root canals was affected by the curing modes of dual-curing luting system and root regions.

Effect of ozone gas application on the mechanical properties of dental adhesives bonded to dentin.

OBJECTIVES: To assess the effect of ozone gas on the mechanical properties of different classes of dental adhesives. METHODS: Extracted molars were sectioned perpendicularly to their long axis for obtaining dentin slices to be bonded with one of the following adhesives: Prime&Bond NT (Dentsply), Excite (Ivoclar-Vivadent), Syntac/Heliobond (Ivoclar-Vivadent) and Silorane System Adhesive (3 M-ESPE). Prior to bonding, the slices were sectioned in two halves: one was treated with ozone gas for 120 s (4.2g/m3; HealOzone, KaVo) and the other served as control. The Vicker's hardness (VH), elastic modulus (E), elastic work (We/Wtot) and the creep (Cr) of the materials were measured with an automatic micro hardness indenter (Fischer) 30 min and 24 h after bonding procedure. Data were analyzed with the multivariate ANOVA followed by the Tukey's test and partial eta-squared statistics. RESULTS: The adhesive and the time of testing were significant factors affecting the investigated parameters (p<0.001; etap2>or=0.06). Dentin treatment, though significant, exerted a minimal effect on mechanical properties (etap2

Post space debridement in oval-shaped canals: the use of a new ultrasonic tip with oval section.

This study evaluates the effect on post space debridement in oval-shaped canals of an experimental ultrasonic tip with oval section (Satelec) compared with a circular ultrasonic tip (KaVo). Thirty teeth with an oval-shaped canal were endodontically treated and obturated and then randomly divided into 3 groups (n = 10) according to the procedure used for post space debridement: Satelec tip, Largo #2 drill + KaVo file, and Largo #2 drill + water. Debris and dentin tubules were evaluated by assigning scores to scanning electron microscope post spaces images; lower scores corresponded to fewer debris and higher number of open tubules. The Satelec group showed significantly lower debris and open tubules scores than KaVo group (p < .05) and control group (p < .05), which differed significantly between each other (p < .05). Also the debris and open tubules scores in different post space regions differed significantly among the experimental groups (p < .001). The oval ultrasonic tip resulted in a better post space debridement than a circular ultrasonic tip in oval-shaped canals.

Flowable composites as intermediate agents without adhesive application in resin composite repair.

PURPOSE: To evaluate the effect of different intermediate resin agents on composite-to-composite microtensile bond strength (microTBS). METHODS: Composite disks (8 x 4 mm) of Gradia Direct Anterior (N = 15) and Filtek Supreme XT (N = 15), stored in a saline solution at 37 degrees C for 1 month, were sandblasted (Microetcher, 50 microm-Al2O3), cleaned (35% H3PO4), and randomly divided into five groups (N = 3) according to the intermediate agent applied. Two flowable composites (Gradia LoFlo; Filtek Supreme XT Flow) and two adhesives (Adper Scotchbond 1XT, Scotchbond Multi-Purpose) were used. As a control, no intermediate agent was applied. Each disk was incrementally repaired (8x8 mm) with the same resin as the respective substrate. By serially cutting each repaired specimen, multiple sticks of about 0.8 mm2 in cross-section were obtained and loaded in tension until failure at a cross-head speed of 0.5 mm/minute. Data were statistically analyzed. Failure mode was examined by stereo- and scanning electron-microscopy (SEM). Additional specimens were prepared to morphologically evaluate the composite-to-composite interfacial quality by SEM analysis. RESULTS: Composite substrate and intermediate agent were significant factors (Two-way ANOVA, P < 0.001). Bond strengths achieved with Gradia Direct Anterior were higher than Filtek Supreme XT. The application of flowable composites resulted in statistically superior microTBS than adhesives and control (Tukey test, P < 0.001). Failure mode was predominantly cohesive (flowable composites), cohesive/adhesive (adhesives) and adhesive (no treatment). Flowable composites and adhesives showed a good interfacial quality.

Post space cleaning using a new nickel titanium endodontic drill combined with different cleaning regimens.

This study compared the effect of two drills and five cleaning regimens on post space debridement. One hundred extracted premolars were instrumented and obturated with warm vertical compaction of gutta percha. The teeth were divided into two groups according to the drill used to remove gutta percha/sealer and for post space preparation: a Largo drill (Largo; Dentsply, St Quentin en Yvelines, France) or a MTwo-PF drill (Sweden&Martina, Due Carrare, Padova, Italy). The following cleaning regimens were used: EDTA, ultrasonics, ultrasonics + EDTA, phosphoric acid, and distilled water. Scanning electron microscopic images of the post spaces were taken, and the presence of debris and of open dentin tubules were evaluated. The ultrasonics + EDTA, phosphoric acid, and EDTA groups were comparable in open tubules scores for both drills and in debris scores after the use of MTwo-PF (p > 0.05). The ultrasonics and control groups performed significantly worse (p < 0.05). The MTwo-PF drill resulted as effective as the Largo drill in obtaining a good post space cleaning, especially when followed by ultrasonics + EDTA irrigant regimen.

Effect of intermediate agents and pre-heating of repairing resin on composite-repair bonds.

This study investigated the composite-to-composite microtensile bond strength and interfacial quality after using different combinations of intermediate agents and pre-curing temperatures of repairing resin. Forty-five composite discs (8x4 mm) of Gradia Direct Anterior (GC Corp), stored in a saline solution at 37 degrees C for one month, were sandblasted (50 microm aluminum oxide), cleaned (35% phosphoric acid) and randomly divided into three groups (n=15) according to the intermediate agent applied: (1) no treatment; (2) unfilled resin (Scotchbond Multi-Purpose Adhesive, 3M ESPE); (3) flowable composite (Gradia LoFlo, GC Corp). Each disc was incrementally repaired (8x8 mm) with the same resin as the substrate. For each group, three subgroups (n=5) were created, depending on the pre-curing temperature of the repairing resin-4 degrees C, 23 degrees C or 37 degrees C. Two bonded specimens per group were prepared to evaluate the composite-to-composite interfacial quality via scanning electron microscope. Microtensile bond strength measurements were performed with the remaining three specimens and failure mode was examined by stereomicroscopy. Two-way ANOVA revealed that temperature (p < 0.001), intermediate agent (p < 0.001) and the interaction (p = 0.002) significantly affected the repair strength. Post-hoc comparisons revealed that bond strengths were significantly lower using a 4 degrees C repairing resin in groups where intermediate agents were used. The highest bond strengths were recorded when flowable composite was used as an intermediate agent under each of the three temperature conditions. Interfacial quality improved by raising the resin temperature from 4 degrees C to 37 degrees C.

Accelerated aging of adhesive-mediated fiber post-resin composite bonds: A modeling approach.

OBJECTIVES: Although fiber posts luted in root canals are not directly exposed to oral fluids, water storage is considered as in vitro accelerated aging test for bonded interfaces. The aim of the study was to evaluate the influence of accelerated water aging on fiber post-resin composite adhesion. METHODS: Forty fiber posts (DT Light Post, RTD) were randomly divided into two main groups, according to the surface treatment performed. Group I: XPBond adhesive (Dentsply Caulk); Group II: sandblasting (Rocatec-Pre, 3M ESPE) and XPBond. Dual-cured resin cement (Calibra, Dentsply Caulk) and flowable composite (X-Flow, Dentsply Caulk) were applied on the posts to produce cylindrical specimens. The bond strength at the interface between post and cement/composite was measured with the microtensile test according to the non-trimming technique. Half of the sticks were tested immediately for bond strength, while in the other half testing was performed after 1 month of water storage at 37 degrees C. Post-cement/composite interfaces were evaluated under SEM prior and after water aging. Statistical analysis was performed using the Kruskal-Wallis ANOVA followed by Dunn's multiple range test (p<0.05). RESULTS: Immediate bond strength was higher on sandblasted posts. After water aging the two post surface treatments resulted comparable in bond strength. Resin cement achieved higher bond strength to fiber posts than flowable composite. Water aging significantly reduced bond strength. CONCLUSIONS: Sandblasting followed by adhesive coating may improve immediate post-resin bond strength in comparison to adhesive alone. However, fiber post-resin bond strength mediated by hydrophilic adhesive tends to decrease after water aging.