Comparative In Vitro Evaluation of Residual Fiber Contamination from Applicators in the Adhesive Interface

Diffusion tensor tractography of residual fibers in traumatic spinal cord injury: A pilot study

Adhesive analysis of voids in class II composite resin restorations at the axial and gingival cavity walls restored under in vivo versus in vitro conditions

Photoelastic analysis of polymerization contraction stresses in resin composite restorations

Background Repair of resin composite restorations consists in a more conservative solution compared to complete replacement. The objective of the present study was to evaluate different surface treatment protocols and their effects on the adhesive interface between the base and the repair resin composite, considering both new and aged restorations.Material and Methods This study evaluated six resin composites (Admira Fusion Xtra/ADM, Filtek Supreme Flowable/FSF, Filtek One/FO, Vitra/VIT, Filtek Supreme/FS, Filtek Bulk Fill Flowable/FBF), five surface treatments (Hydrofluoric acid 120s+silane/HFs, Phosphoric acid 30s/P30, Phosphoric acid 30s+silane/P30s, Sof-lex+phosphoric acid 30s/SP30, Sof-lex+phosphoric acid 30s+silane/SP30s), and two repair timepoints (immediate and after 1 year simulated aging aged). Forty disks for each resin were divided into 10 groups according to surface treatment and repair timepoints (n=4 disks per subgroup). Surface treatments were performed, followed by application of a universal bonding agent (Scotchbond Universal). Filtek Supreme/FS was used as the repairing resin, and three cylinders of material were cemented on each resin disk. Notched shear bond strength test was performed using a universal testing machine, contact angle tests were performed using a goniometer, and fracture mode analysis was performed using a stereomicroscope.Results All factors and their interactions were significant for both shear bond and contact angle tests (p<.001 for all criteria). Overall results for shear bond strength showed SP30=SP30s>P30=P30s>HFs; immediate<aged; and FS=FO>VIT>FBF=FSF>ADM. Similarly, overall results for contact angle showed P30>HFs>SP30; aged>immediate; and FSF>VIT=FBF>FS=FO>ADM. Immediate resin samples treated with mechanical roughening exhibited lower number of adhesive failures compared to other treatments. In aged samples, groups treated with mechanical roughening and/or silane agent showed a predominance of cohesive and/or mixed failure modes. Shear bond strength is influenced by the type and age of the base resin composite, as well as the surface treatment applied.Conclusions Despite a tendency for higher results when mechanical roughening is associated with Scotchbond Universal, there is not a clear difference to justify its use in most of the resin composites. Furthermore, most of the surface treatments performed similarly, regardless of the base resin composite. Key words:Resin composite, resin repair, surface treatments, bulk-fill composite, adhesive interface.

OBJECT Hemispherectomy for unilateral, medically refractory epilepsy is associated with excellent long-term seizure control. However, for patients with recurrent seizures following disconnection, workup and investigation can be challenging, and surgical options may be limited. Few studies have examined the role of repeat hemispherotomy in these patients. The authors hypothesized that residual fiber connections between the hemispheres could be the underlying cause of recurrent epilepsy in these patients. Diffusion tensor imaging (DTI) was used to test this hypothesis, and to target residual connections at reoperation using neuronavigation. METHODS The authors identified 8 patients with recurrent seizures following hemispherectomy who underwent surgery between 1995 and 2012. Prolonged video electroencephalography recordings documented persistent seizures arising from the affected hemisphere. In all patients, DTI demonstrated residual white matter association fibers connecting the hemispheres. A repeat craniotomy and neuronavigation-guided targeted disconnection of these residual fibers was performed. Engel class was used to determine outcome after surgery at a minimum of 2 years of follow-up. RESULTS Two patients underwent initial hemidecortication and 6 had periinsular hemispherotomy as their first procedures at a median age of 9.7 months. Initial pathologies included hemimegalencephaly (n = 4), multilobar cortical dysplasia (n = 3), and Rasmussen's encephalitis (n = 1). The mean duration of seizure freedom for the group after the initial procedure was 32.5 months (range 6-77 months). In all patients, DTI showed limited but definite residual connections between the 2 hemispheres, primarily across the rostrum/genu of the corpus callosum. The median age at reoperation was 6.8 years (range 1.3-14 years). The average time taken for reoperation was 3 hours (range 1.8-4.3 hours), with a mean blood loss of 150 ml (range 50-250 ml). One patient required a blood transfusion. Five patients are seizure free, and the remaining 3 patients are Engel Class II, with a minimum follow-up of 24 months for the group. CONCLUSIONS Repeat hemispherotomy is an option for consideration in patients with recurrent intractable epilepsy following failed surgery for catastrophic epilepsy. In conjunction with other modalities to establish seizure onset zones, advanced MRI and DTI sequences may be of value in identifying patients with residual connectivity between the affected and unaffected hemispheres. Targeted disconnection of these residual areas of connectivity using neuronavigation may result in improved seizure outcomes, with minimal and acceptable morbidity.

Introduction: For adhesive systems to be considered efficient they should maintain restorations stable and with adherence. They also should be capable to seal restorations margins against oral fluids and microorganisms for a long period [1,2]. Adhesive interface permeability to water and other oral fluids is possible even in restorations without detectable pores since their entry can be done through nanometric defects [2,3]. This adhesive interface degradation by hydrolysis can negatively affect adhesion durability leading to an adhesive interface degradation, process that Sano in 1995, called nanoleakage [4,5]. The aim of this study was the nanoleakage evaluation of universal adhesive systems, by SEM-EDS with Etch-and-rinse and Self-Etch approach. Materials and methods: This work was approved by the IUEM Ethics Committee. 24 intact human molars extracted for orthodontic or periodontal reasons were randomly divided into 12 groups (n = 2), 6 control and 6 experimental. Three universal adhesive systems, Futurabond® U, Prime & Bond® Active™ and Scotchbond™ Universal, were tested in their etch-and-rinse and self-etch approaches. Teeth were cut in a hard tissues microtome to expose superficial dentin and were polished with a 400 grit SiC paper. Adhesives were applied according to manufacturer’s instructions and resin build-ups were obtained with Filtek Z250 resin (colour A2) with 2 mm increments up to a maximum of 6–8 mm. Samples were sectioned in the X direction on a hard tissue microtome in order to obtain slices of 0.7 mm. 10 slices were selected for each group. In the control groups samples were stored in 5 ml of oil (VV Lubricant) for 3 months in an oven at 37 °C in order to avoid the hydrolytic degradation process and the experimental groups were stored in 5 ml of deionized water for 3 months in an oven at 37 °C so that it was possible to observe the hydrolytic degradation. After the incubation period samples were prepared and subjected to SEM-EDS nanoleakage tests. Statistical analyses with a Mixed Linear Model (MM), with Akaike (AIC), Hurvich andTsai (AICC), Bozdogan (CAIC) and the Bayes and Schwarz (BIC) information criteria were done. Results: No significant differences were found between universal adhesives. However, there was a significant difference concerning the adhesion strategy. The previous acid conditioning caused a greater expression of the nanoleakage. Discussion and conclusions: In our study we verify that when universal adhesives were applied with the etch-and-rinse approach the adhesive interface percentage infiltrated with silver nitrate is significantly higher that when adhesives were applied in the self-etch approach. These results are in accordance with other studies found in literature. Marchesi et al. [6] observed that nanoinfiltration was significantly reduced when Scotchbond Universal adhesive was applied as self-etch. In another study Luque-Martinez et al. [7] studied three universal adhesives: Scotchbond Universal, All-Bond Universal e Prime&Bond Elect and found that all presented significantly higher nanoinfiltration when applied as etch & rinse. The same results were found by Muñoz et al. [8] for the All-Bond Universal and G-Bond adhesives. The self-etch application of these universal adhesives seemed to contribute to the stability and durability of the adhesive interface.

To investigate the shrinkage-induced damage at the composite-tooth interface by finite element analysis (FEA) using the cohesive zone model (CZM). Axisymmetric models of Class I restorations were created to illustrate the interfacial damage around composite resin restorations of different dimensions, with polymerization shrinkage modeled analogously to thermal shrinkage. The damage to the adhesive interface was determined using a CZM based on the fracture strength and fracture energy. To show the effects of damage, conventional models with perfectly bonded composite resin restorations were created as controls. The results indicated interfacial damage at the butt-joint cavosurface margin, dentinoenamel junction, and internal line angle. The percentage of damaged interfacial area was found to increase with decreasing diameter for restorations of the same height. For a given diameter, the damage was more severe for restorations of greater depth. The effects of the damage were further illustrated in the model with a restoration of 2-mm diameter and height. The interfacial damage occurred primarily at the internal line angle (83.3% of all the damaged interfacial area), leading to local stress relief (from 18.3MPa to 12.8MPa), but also higher stress at the damage fronts. Greater local shrinkage was found in composites adjacent to the damage. The damage mechanics-based CZM is an essential refinement of the FEA to predict interfacial damage and its implications. The extent of damage was found to be greater around restorations with smaller diameters and greater depths. The entire simulation is available via an open-source platform to facilitate further applications in adhesive dentistry.

In the context of climate change, a special interest has been aroused by thermal insulator materials from natural fibers, which can promote sustainable construction in the sector. The objective of this research was to evaluate the potential of the residual fibers of Pisum Sativum (PS), for their future use in the development of a thermal insulator material with low environmental impact. The physical, chemical and thermal properties of the fiber were determined. The results shows that the residual fiber has a great potential with an extraction of raw material of 11.6%. It shows a good proportion in the length of its fibers and roughness and significant number of grooves, which is verified using a scanning electron microscope and after thermal conductivity tests that indicate a best value of 0.033 W/mK. It is therefore concluded that from the residual fibers of PS, an opportunity is generated for the food residual fibers within the sustainable construction industry, given the proposed innovation and its interesting results, which could contribute with its low environmental impact throughout the life cycle of buildings.

Relationship of wall orientation to proximal ☐ design in inlay preparations

Effect of low-elastic modulus liner and base as stress-absorbing layer in composite resin restorations

Variation and mechanism of asphalt-aggregate interface features under ultraviolet aging based on meso- and micro-observations

Clinical evaluation of internal axial wall divergence in inlays and casting post-and-core fabrication

HPLC analysis of bisphenol-A elution from resin composites after aging

Objective:The aim of the study was to evaluate the microtensile bond strength (µTBS) of Scotchbond Universal to dentin using the etch-and-rinse or the self-etch technique after 24 h and 6 months of storage.Materials and Methods:Flat dentin surfaces were obtained in 24 third molars. The teeth were divided into four groups: G1 – Scotchbond Universal applied in the etch-and-rinse mode; G2 – Scotchbond Universal applied in the self-etch mode; G3 – Scotchbond Multi-Purpose; G4 – Clearfil SE Bond. A block of composite was built on the adhesive area. The tooth/resin sets were cut parallel to the long axis to obtain 40 beams (~0.8 mm2) for each group. Twenty specimens were immediately submitted to the µTBS test, and the remaining 20 were stored in water for 6 months. Failures and the adhesive interface were analyzed by SEM.Results:According to two-way ANOVA, the interaction between adhesive and storage time was significant (p=0.015).The µTBS (MPa) means were the following: 24 h – G1 (39.37±10.82), G2 (31.02±13.76), G3 (35.09±14.03) and G4 (35.84±11.06); 6 months – G1 (36.99±8.78), G2 (40.58±8.07), G3 (32.44±6.07) and G4 (41.75±8.25). Most failures were mixed. Evidence of hybrid layer and numerous resin tags were noted for Scotchbond Universal applied with the etch-and-rinse mode and Scotchbond Multi-Purpose. A thinner hybrid layer and fewer resin tags were noted for Scotchbond Universal applied in the self-etch mode and Clearfil SE Bond.Conclusion:The results indicate that the µTBS for Scotchbond Universal is comparable to the gold-standard adhesives. Scotchbond Universal applied in the self-etch mode and Clearfil SE Bond revealed higher bond stability compared to the etch-and-rinse mode.

Adhesive system properties and its behavior under simulated pulpal pressure in sound and caries-affected dentin and aging