СРАВНИТЕЛЬНЫЙ АНАЛИЗ ЭЛЕМЕНТНОГО СОСТАВА ЗОНЫ АДГЕЗИОННОГО СОЕДИНЕНИЯ АДГЕЗИВНЫХ СИСТЕМ IV ПОКОЛЕНИЯ С КЕРАМИЧЕСКИМИ КОНСТРУКЦИЯМИ МЕТОДОМ РЕНТГЕНОВСКОГО МИКРОЗОНДОВОГО АНАЛИЗА

This study assessed the bond strength of resin-based restorative materials to fast-setting calcium silicate cement (Aarhus Uinversity, Denmark) when treated with each of two one-bottle universal adhesive systems. The cement surface (N=256) was treated with a self-priming adhesive and a self-etch phosphate monomer-containing adhesive with and without etching of the cement surface. Specimens then received either resin composite or compomer restorative materials (n=32). The bond strength was measured after 1 day and 1500 thermocycles (n=16). The failure type was visually inspected. The cement-adhesive-restorative material interface was visualized using scanning electron microscopy (SEM). The data were analyzed using multiple linear regression. Restorative material type, resin adhesive system, and thermocycling had a statistically significant effect on the bond strength. Compomer restorative material and self-etch universal adhesive system demonstrated statistically significantly higher bond strength values to fast-setting calcium silicate cement, predominantly exhibiting cement cohesive failure. Etching the cement surface enhanced the bond strength of the self-priming universal adhesive. Thermocycling significantly reduced the bond strength. SEM showed self-etch universal adhesive seemingly diffused over the etched cement surface compared to other groups. Self-etch phosphate monomer-containing universal adhesive and compomer resulted in the highest bond strength to fast-setting calcium silicate cement.

The information regarding the cytotoxicity of ceramic and resin-matrix ceramic materials subjected to over-the-counter bleaching agents is limited in the literature. The aim of the present study was to investigate the cytotoxic effects of lithium disilicate ceramic (LDC), resin nano-ceramic (RNC) and nano-hybrid composite (NHC) computer-aided design/ computer-aided manufacturing (CAD-CAM) block materials subjected to a home bleaching agent and artificial saliva. A total of 432 specimens were prepared from 3 different CAD-CAM materials. Each material group was divided into 4 groups according to the storage medium (phosphate-buffered saline (PBS) or artificial saliva), and whether the specimens were subjected to a bleaching agent or not. For the bleached groups, hydrogen peroxide (10%) was applied to the specimens for 30 min/day for 15 days, and the specimens were immersed in PBS or saliva after bleaching. The viability of epithelial cells was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay at the end of the 5th, 10th and 15th day of the study. The data was statistically analyzed. Regardless of the storage medium and the time period, all restorative materials decreased the viability of cells. The highest cytotoxicity levels were determined on the 15th day of the study. The application of a bleaching agent increased the cytotoxicity of the LDC specimens stored in artificial saliva. The RNC material stored in PBS demonstrated significantly higher cell viability than the LDC and NHC groups. The LDC and RNC specimens stored in artificial saliva did not show any significant difference in cytotoxicity. When the materials were subjected to bleaching, NHC demonstrated the highest cytotoxicity during all periods. No significant difference was found between the LDC and RNC specimens subjected to both artificial saliva and bleaching in terms of cytotoxicity. The type of restorative material, the immersion medium, the application of a bleaching agent, and the application period affected the cytotoxicity of the materials. Over-the-counter home bleaching agents may induce cellular cytotoxicity due to the existing restorations, and patients should be informed about this potential biological response.

New technologies are changing the therapeutical options to do indirect restorations and new adhesive systems are continuously introduced to be used by clinicians. Different interactions between restorations, adhesive systems components, enamel and dentin require having criteria based on the selection of the adhesive system, ensuring the longevity of the restorations and the preservation of the biological remnant. The adhesion force to the dental tissue is one of the indicatives of the behavior of the adhesive systems and influences the behavior of the treatments with direct and indirect restorations. The objective of this search was to find the adhesive systems with the best results in terms of the adhesion strength of indirect restorations on the dental tissues. The search was conducted in two MEDLINE digital databases (PubMed), and the Cochrane Library with a search strategy based on the combination of MeSH (Medical Subject Headings) keywords. This systematic review used the PRISMA guide (Preferred Reporting Items for Systematic Reviews and Meta-Analysis). According to this review, the 3-step adhesive systems were the best performing and still are the gold standard for the cementing of indirect restorations. In addition, it can be concluded that self-etched adhesive systems reduce the time spent in clinical practice, however at the interface level they behave as permeable membranes more susceptible to degradation.

Background: The aim of this research was to study the effect of air-abrasive treatment of dentin on the chemical composition of its surface and the adhesion strength of 2 self-etching adhesive systems (AS). Methods and Results: Powders based on aluminum oxide (Al2O3) (27µm) (KaVo, Biberach, Germany), sodium bicarbonate (NaHCO3) (40µm) (AIR-FlOW Classic Comfort, EMS, Nyon, Switzerland), and erythritol (14µm) (AIR-FLOW Plus, EMS, Nyon, Switzerland) were used for the air-abrasive treatment of adhesive surfaces. Bonding steps were carried out with Single Bond Universal (SBU) (3M ESPE, USA) and Bond Force 2 (BF2) (Toquyama, Japan). The adhesion strength of composite to dentin was evaluated on 80 samples prepared in accordance with the Ultradent Shear Bond Strength test. All samples were divided into 4 groups depending on the method of dentin surface processing. In the samples of Group 1 (n=20), aluminum oxide was used for the air-abrasive treatment of dentin. In Group 2 (n=20) and Group 3 (n=20), samples were treated using powders based on sodium bicarbonate and erythritol, respectively. Group 4 (control, n=20) included tooth samples in which the dentin surface was not air-abraded after preparation with carbide burs. Then, each group was divided into 2 subgroups (Sub-A and Sub-B) depending on the type of adhesive system used. Adhesive resin was applied and polymerized in accordance with the manufacturer’s instructions. Single Bond Universal (SBU) was used for the samples of Sub-A, and Bond Force 2 (BF2) (Toquyama, Japan) was used for the samples of Sub-B. Scanning electron microscopy and determining the surface elemental composition of samples were carried out on an SEM-EVO MA 10 (Carl Zeiss) and energy dispersive X-ray spectrometer with EDS Aztec Energy Advanced X-Act (Oxford Instruments). It was concluded that air-abrasive treatment of the dentin surface does not enhance the adhesion strength of composite material when using self-etch AS. Also, it was noted that the pH level of self-etch AS is not a crucial feature in determining the strength of the filling-tooth interface. The resulting variations in the elemental composition of dentin surface after air-abrasion with various mixtures and their effect on the efficacy of the different AS require further in vitro studies.

To evaluate the bonding of simplified adhesive systems to sound and caries-affected dentin of primary teeth with microtensile (µTBS) and nanoleakage (NL) tests. Occlusal cavities were prepared in 36 sound second primary molars. Half of the specimens were submitted to pH cycling to simulate caries-affected dentin. Teeth were randomly restored with one of three materials: the etch-and-rinse adhesive system Adper Single Bond 2 (SB), the two-step self-etching adhesive system Adper SE Plus (SE), and the one-step self-etching adhesive system Adper Easy One (EASY). After storage for 24 h, specimens with cross-sectional areas of 0.8 mm2 were prepared for microtensile testing (1 mm/min). One stick from each tooth was immersed in silver nitrate solution (24 h) and allowed to develop for 8 h in order to score the nano leakage with SEM. The fracture pattern was evaluated using a stereomicroscope (400X). The µTBS means were analyzed by two-way ANOVA and Tukey's post-hoc test. For NL, the Kruskal- Wallis and Mann-Whitney tests were used (α < 0.05). SB (35.5 ± 3.5) showed the highest µTBS value to sound dentin, followed by EASY (26.3 ± 1.9) and SE (18.2 ± 6.5) (p < 0.05). No difference among materials was observed for caries-affected dentin (SB: 17.8 ± 4.2; SE: 13.9 ± 3.2; EASY: 14.4 ± 4.2, p > 0.05). For all groups, adhesive/mixed fracture prevailed. Caries affected dentin promoted silver nitrate uptake into the adhesive interface; however, with SE, the nano leakage was more pronounced than in the other adhesive systems, even in sound dentin. Caries-affected dentin negatively influences the bond strength and nano leakage of the two-step etch-and-rinse and one-step self-etching adhesive systems tested in primary teeth.

Effect of resins sealing of dentin on the bond strength of ceramic restorations

This study evaluated how a matrix metalloproteinase (MMP) inhibitor (EGCG) incorporated into an etch-and-rinse adhesive system (AS) affects the long-term microtensile bond strength (MTBS) to caries affected dentin (CAD) and flexural strength (FS) of AS. Forty CAD surfaces received acid conditioning and were randomly divided into four groups (n = 10): EGCG-PRE – dentin treatment with 200 μg/mL EGCG solution; EGCG-INC – 200 μg/mL EGCG solution incorporated into SA; CHX-PRE – dentin treatment with 2% digluconate solution; NT – no treatment. The AS (Adper Single Bond 2, 3M ESPE) was applied and resin composite blocks were built on the dentin. Beam-shaped specimens (0.8 mm2) were obtained submitted to MTBS testing following 24 h, 6 months or 1 year of water storage (WS). Adhesive interface was analyzed by SEM. FS testing was performed by preparing specimens with the adhesive system, with or without the EGCG solution (200 μg/mL) (n = 10). Tests were carried out in a universal machine (0.5 mm/min). MTBS data were submitted to two-way ANOVA and Tukey’s test, whereas FS data, to the Student’s t-test (α = 0.05). MTBS values were not affected by EGCG application, either incorporated or used as a dentin treatment agent, regardless of the WS period; however, CHX negatively affected MTBS to CAD (p < 0.001). WS significantly reduced MTBS values (p < 0.001) from the 6-months time point. FS was not affected by EGCG incorporation into the SA (p = 0.2527). EGCG incorporation into AS was unable to maintain bond stability to CAD over time, whereas it did not compromise adhesive’s property.

Establishing a strong bond between the pulp capping agent and the restorative material is crucial to the success of the procedure. Without this bond, there is a risk of bacterial infiltration into the pulp, leading to treatment failure. In the past, calcium hydroxide was commonly used for such treatments, but it faced challenges, including poor adhesion to dentin, dissolution over time, and the development of multiple tunnel defects. Mineral trioxide aggregate (MTA), introduced to dentistry in 1993, offered an alternative but came with drawbacks like challenging handling and extended setting times. However, in recent times, several new calcium silicate-based materials have emerged to address MTA's limitations. Two notable examples are Biodentine and MTA Plus. Biodentine, for instance, exhibits excellent sealing ability, while MTA Plus distinguishes itself with a finer particle size compared to traditional MTA. These innovative materials offer promising solutions to enhance the efficacy of pulp capping procedures. Therefore, in this research, we conducted a comparative analysis of the shear bond strength (SBS) between composite resin and three materials-MTA, MTA Plus, and Biodentine. We examined the effects of applying two distinct adhesive systems in order to evaluate their influence on the bond strength. A total of 60 acrylic blocks were evenly distributed into three groups, each containing 20 blocks-group I received Biodentine, group II was assigned MTA, and group III received MTA Plus. The respective test materials were compacted into the holes within the blocks. Following this, the samples were incubated for a period of 72 hours. Subsequently, the samples were divided into two subgroups, each consisting of 10 blocks-the self-etch and the total-etch subgroup. The SBS values were then carefully measured for analysis. The SBS of the Biodentine group demonstrated a significantly higher value when compared to the other groups. It's worth noting that when the self-etch adhesive system was employed, the SBS of all the groups experienced a significant reduction. Biodentine cement proves to be an effective choice for pulp capping procedures, regardless of the specific adhesive system employed. Notably, the total-etch adhesive system consistently yields higher bond strength when compared to the self-etch adhesive system. Kumar V, Showkat I, Manuja N, et al. Comparative Evaluation of Shear Bond Strength of Tricalcium Silicate-based Materials to Composite Resin with Two Different Adhesive Systems: An In Vitro Study. Int J Clin Pediatr Dent 2023;16(S-3):S272-S277.

Important direction of technological progress is creation of substances, materials, and articles with controlled properties. Development of nanotechnologies will result in mass production of substances, materials, and articles containing nanoparticles. This poses new problems to forensics: identification and differentiation of nanomaterials by their properties. Determination of specific features of structure, composition, and other physicochemical properties of objects produced by nanotechnologies may form the basis for solving diagnostic and identification problems by forensic experts. The purpose of this work was to test a number of methods for studying nanostructures for forensic examination by the example of identification of signs of difference between documents printed by xerography. Such an expert problem takes place if it is necessary to establish the fact of substitution of pages of a contract or insertion of a text into a ready document. The objects of investigation were magnetic toners used in laser and multifunction printers (more than 50% sales in the market). Modern magnetic toners are sophisticated composites the base of which is ~5- µ m particles of a thermoplastic (e.g., a styrene‐acrylate copolymer). The particle surface is modified by aerosil, alumina, or titanium dioxide particles [1] to impart fluidity to toner powders. Among other compounds that are in the bulk of the particles and determine the stability of electrostatic, magnetic, and other properties of toner are magnetite nanoparticles (10‐15 vol %). In making a print, toner from a hopper is attracted to the surface of a roller under the action of a magnet from which the roller core is made. As the roller rotates, the toner on its surface passes through a narrow slit between a metering blade and the roller, contacts a photoconductive drum, and is attracted to the drum surface at places where a negative charge was neutralized by a scanning laser beam. Toner particles are transferred as an image from the photoconductive drum to paper because of electrostatic interaction between the drum and the charged paper surface and stuck to the paper owing to the thermoplastic properties of the polymer base of toner particles. Thus, a text made by xerography is small amounts (micrograms) of toner affixed by heat treatment to paper as printed characters. Modern printers use several hundreds of types of toners of similar compositions. In this work, we studied mainly toners produced by Hewlett-Packard (HP) and Canon and also samples of characters printed by printers of these companies. The samples were the characters “n” of font size 14 that were cut off from the body text as 3 × 3-mm paper squares. Morphological features of the surface of the text characters were investigated by electron microscopy with a Leo Supra 50 VP scanning electron microscope (Carl Zeiss, Germany) with a field-emission source at an accelerating voltage of 3‐10 kV using an InLens secondary electron detector. The chemical composition of toners and the element distribution over the character surface was were found by electron probe X-ray microanalysis with the same instrument using an INCA Energy+ energy-dispersive X-ray spectrometer (Oxford Instruments, UK) at an accelerating voltage of 20 kV within a selected range.

Normal 0 21 false false false TR X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:Normal Tablo; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Times New Roman; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;} Objectives : T he objective of this study was to evaluate the effect of thermal cycling on microtensile bond strengths (MTBS) of various adhesives to dentin. Methods: Three adhesive systems including a 1-step self-etch adhesive system (G-Bond), a 2-step self-etch adhesive system (AdheSE), and an e tch&rinse adhesive system ( Prime & Bond NT) were evaluated. Twenty-four extracted molars were used. After grinding the coronal enamel surface, the teeth were randomly divided into 6 groups ( n =4) (G-Bond, G-Bond+thermal cycling, AdheSE, AdheSE+thermal cycling, Prime & Bond NT, and Prime & Bond NT+thermal cycling). Adhesives were applied according to each manufacturer’s instructions followed by resin composite polymerization. Groups without thermal cycling were stored in distilled water at 37 0 C for 24 hours and used for immediate testing of the MTBS. Groups with thermal cycling were subjected to thermocycling (10.000 cycles between 5 0 C and 55 0 C, for a dwell time of 30 seconds). For MTBS test, teeth were sectioned occluso-gingivally into a serial slabs and further sectioned into composite-dentin sticks. Testing was performed on a universal testing machine at a crosshead speed of 1.0 mm/min. One-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests ( α =0.05) were performed on all data. Results: The results of the MTBS test showed that the highest bond strengths were observed in e tch&rinse adhesive groups (3 and 3T). A statistically significant difference in MTBS was found between group 1 and group 1T ( p p =1.000). Conclusions: Contrary to result with 1 -step self-etch adhesive , thermal cycling was found ineffective on the MTBS of the 2 -step self-etch and e tch&rinse adhesive systems. Keywords: Adhesive, thermal cycling, microtensile bond strength.

Using nanotechnology to produce composite materials it has been possible to obtain materials with similar or better mechanical properties than previous generation of microhybrids, and with exceptional aesthetics and chandelier due to the particularities of nanomaterials. At the same time, the improvement of adhesive techniques to enamel and dentin allowed the expansion of the area of direct composite restorations with a better prognostic over time.Eight carie-free molars were used and each of them was prepared with two class II cavities, which were filled using the C13 and C20 nanocomposites and the A1 and A2 experimental adhesive systems prepared at the Raluca Ripan Chemistry Research Institute. The teeth were divided into four groups of two teeth each, depending on the adhesive system and the composite material used. Scanning electron microscopy images (SEM) have described the adhesive interface and structure characteristics for the two nanocomposite materials and for the two studied adhesive systems.The studied nanocomposites have a variable number of porosities and air bubbles, with a clinical importance which is yet hard to establish.The experimental adhesives used produce a good interface and infiltration of the smear-layer but have not been visualized inside the dentinal canals.In vitro studies are necessary to evaluate the durability of adhesion in the case of self-etch adhesives in one or two steps.

The mechanisms of experimental external contamination which was obtained by immersing hair specimens in solution, especially the contamination through the airsac in medulla on cross section of hair was studied.The hair specimens which have medulla and obtained from one person were cut into the sections of 2cm in length. Untreated hair, the hair covered with Araldite on one end and the hair covered with Araldite on both ends were prepared. These hairs were contaminated externally by immersing them in NaCl solutions with sodium concentration of 9.4×104ppm and pH values of 7 and 11.1 for 1 hour and 24 hours. These contaminated hairs were cut into three portions along the major axis and sodium contents were determined by atomic absorption spectrometry. The distribution of sodium on the cross sections of other parts of the above specimens was determined by electron probe X-ray microanalyzer (XMA).XMA used was a JEOL SMU3-SDS. The operating conditions were 20KV acceleration voltage, 7.5-9.5×10-9A specimen current, RAP for Na-Kα as crystal and×500 magnification.The higher the pH value in immersing solution and the longer the immersing time, the higher the sodium contents in contaminated hair. One difference in sodium content was observed in the means of the three portions of untreated hair and the hair covered with Araldite on both ends which were immersed in the solution with pH value of 11 for 24 hours.As a result of XMA, gradual impregnations of sodium into the inner part of hair from outer layer were observed in the samples immersed in the solutions with pH value of 7 and 11 for 1 hour and all samples were impregnated with sodium into the medulla by the immersion for 24 hours. The higher the pH value, the faster the permeance. Especially higher sodium concentrations in medulla were observed in the samples immersed in the solution with pH value of 11 for 24 hours, regardless of the treatment with Araldite.It was thought that the higher sodium observed in the medulla of the hair covered with Araldite on both ends penetrated from cuticle of hair, because Araldite did not permeate NaCl solution. In addition, it was demonstrated that sodium penetrated also in the direction of hair axis, from the fact that in the hair covered with Araldite on both ends, sodium was detected also in the part of the hair covered entirely with Araldite.

Electron microprobe X-ray analysis was used to determine the transversal microdistribution of P, K, Mg, Ca, Fe, and Mn, with special attention to the outer layers of rice and wheat grains. P, K, Mg, Fe, and Mn were concentrated in the aleurone layer in each case. In particular, P, Mg, and K were highly concentrated in the subcellular particles of the aleurone layer, and had very similar distribution patterns in the outer layers of the matured grain of rice and wheat. By contrast, Ca was abundant in the pericarp.

Background and Objective The potential benefits of the effects of lasers on dental tissues have yet to be realized but may be brought closer through the availability of a suitable laser. The objective of this project is to examine the surface morphological changes resulting from hydrogen fluoride (HF) laser radiation on tooth and restorative material surfaces. Study design/Materials and Methods: A hydrogen fluoride laser emitting at 2.9 μm is used to interact with a range of dental hard tissue and restorative materials. The surface morphological changes induced by 100 mJ pulses of <1 μs duration is studied using a SEM. Results The irradiated surfaces displayed microstructures similar to those of a mechanically fractured surface with no evidence of melting. Conclusion This study suggests that tissue is removed by micro-explosion, leaving a surface free from thermal damage with surface characteristics that would appear to facilitate the adhesion of restorative materials. Lasers Surg. Med. 21:1–6, 1997 © 1997 Wiley-Liss, Inc.

The main purpose was to evaluate the in vitro adhesion strength of direct and semi-direct composite resin restorations in dentin, when the same adhesive system is applied, using microtensile testing (μTBS) and to observe the most recurrent types of failure in the different groups. For this study, 16 intact human mandibular molars without microscopic evidence of lesions were randomly divided into two test groups, according to the restoration strategy: direct restoration (DR) and semi-direct restoration (SR). For both restorative strategies, the same adhesive system (Clearfil SE Bond 2, Kuraray, Tokyo, Japan) was applied to the dentin surface using a two-step self-etching approach with no prior conditioning of the dentin, and the same composite resin (Ceram. x Sepctra ST HV, Dentsply Sirona, Charlotte, NC, USA) was used as a restorative material. The indirect restoration was cemented using resin cement (Variolink Esthetic LC, Ivoclar Vivadent, Schaan, Liechtenstein) within the interior side of the restoration. Each specimen was sliced into sections measuring approximately 1 mm2. The rods were then subjected to a microtensile bond strength test and the statistical analysis on the differences in μTBS between the groups were determined with the Mann–Whitney test. The surfaces were examined to determine the failure mode. The Chi-Square test was used to determine the association between the type of restoration and the failure mode. The DR group presented with a mean μTBS of 38.15 ± 10.75 MPa and a predominance of cohesive failures in the composite resin (69.5%). The SR group showed a mean μTBS of 25.45 ± 10.19 MPa and a predominance of adhesive failures (92.3%). There was not only a statistically significant difference in the adhesive strength of the DR and SR groups (p &lt; 0.001), but also a statistically significant association between the type of restorative strategy and failure mode (p &lt; 0.001). Even though Clearfil SE Bond 2 provided acceptable adhesion to the dentin, using the same two-step self-etch adhesive system, lower adhesive strength and more adhesive failures are expected in semi-direct restorations when compared to direct restorations.