Self-adhesive Materials Research Articles

Application of Olivine Powder as a Filler for Silicone Pressure-Sensitive Adhesives

In this work, new self-adhesive materials were obtained based on cross-linked silicone self-adhesives obtained by modifying the composition with the addition of a silicon filler, olivine. Silicone pressure-sensitive resin DOWSIL 7358 was used as a basis and modified with various amounts of olivine. New materials (self-adhesive tape samples) were characterized in terms of peel adhesion, tack, cohesion at room and elevated temperatures, SAFT test (shear adhesion failure temperature), pot life (storage stability), and shrinkage (dimensional stability). During the tests, an increase in thermal resistance (>225 °C) and a drastic reduction in shrinkage values (below 0.5%) were noted for all modified samples tested. All tests were performed in compliance with international standards, e.g., FINAT FTM 1, FINAT FTM 8, FINAT FTM 9, FINAT FTM 14, and GTF 6001. This allows us to conclude that the new material has significant application potential due to the good performance results. The results of adhesion and tack were in ranges accepted in the PSA industry, cohesion was kept at an unchanged level (above 72 h), and a great increase in the thermal resistance was observed (from 147 °C for pure resin to high above 225 °C for even the smallest additions of the olivine powder. Moreover, the shrinkage of prepared adhesive films was reduced significantly. In the available literature, there are no references to the modification of adhesives using powdered silicon minerals of natural origin, which is a novelty due to their higher bulk density compared to commercial powdered silicon fillers.

Influence of Talc on the Properties of Silicone Pressure-Sensitive Adhesives.

The article describes new silicone self-adhesive adhesives modified with the addition of talc. The obtained self-adhesive materials were characterized to determine their adhesive properties (adhesion, cohesion, and adhesion) and functional properties (pot life of the composition, shrinkage, and thermal properties of adhesives). Novel materials exhibited high thermal resistance above 225 °C while maintaining or slightly reducing other values (adhesion, cohesion, shrinkage, and tack). Selected composition: T 0.1 was used to prepare self-adhesives in industrial-scale production. Moreover, conducted test results revealed that the addition of talc delayed the thermal decomposition of the adhesive and provided reduced intensity of smoke emissions during combustion as well as the flammability of the adhesive layer.

Peeling-Stiffening Self-Adhesive Ionogel with Superhigh Interfacial Toughness.

Self-adhesive materials that can directly adhere to diverse solid surfaces are indispensable in modern life and technologies. However, it remains a challenge to develop self-adhesive materials with strong adhesion while maintaining its intrinsic softness for efficient tackiness. Here, a peeling-stiffening self-adhesive ionogel that reconciles the seemingly contradictory properties of softness and strong adhesion is reported. The ionogel contains two ionophilic repeating units with distinct associating affinities, which allows to adaptively wet rough surface in the soft dissipating state for adhering, and to dramatically stiffen to the glassy state upon peeling. The corresponding modulus increases by 117 times driven by strain-rate-induced phase separation, which greatly suppresses crack propagation and results in a super high interfacial toughness of 8046 J m-2 . The self-adhesive ionogel is also transparent, self-healable, recyclable, and can be easily removed by simple moisture treatment. This strategy provides a new way to design high-performance self-adhesive materials for intelligent soft devices.

Green, recyclable, mechanically robust, wet-adhesive and ionically conductive cellulose-based bioplastics enabled by supramolecular covalent hydrophobic eutectic networks

The development of novel cellulose-based bioplastics (CBPs) is highly desirable because CBPs are green, rationally use resources, and lead to a reduction in environmental pollution compared to alternative materials. However, incorporating high transparency, water resistance, mechanical robustness, wet-adhesion, ionic conductivity and recyclability into CBP remains a challenge. In this paper, novel CBPs with supramolecular covalent networks are fabricated by introducing polymerizable hydrophobic deep eutectic solvents (HDES) into ethylcellulose (EC) networks through in situ plasticization followed by a rapid photopolymerization process. The excellent molecular interfacial compatibility enables EC to be loaded with a high content of poly(HDES), while allowing high transparency (more than 90 %) of the prepared CBPs. Multiple intermolecular interactions provide CBPs with mechanical robustness, water resistance, and underwater adhesion, and CBPs can be readily recovered by the solvent in a closed loop. Moreover, CBPs possess inherent ionic conductivities, and using them as green substrates, personalized electroluminescent devices can be successfully constructed. The method proposed in this paper provides a new strategy for the preparation of multifunctional CBPs, which will greatly enrich their applications in self-adhesive materials, green flexible electronics and other package materials.

12-Month flexural mechanical properties of conventional and self-adhesive flowable resin composite materials.

The aim of this study was to investigate the 12-month flexural mechanical properties of 23 flowable resin-based composites (FRBC) that included 5 self-adhesive FRBC materials. Specimens were evaluated following ISO 4049:2019 guidelines, but additionally stored in physiologic 0.2M phosphate buffered saline solution being tested at 24 h, 1 week, 1 month, and at 3-, 6-, 9-, and 12-months. While some deviation and degradation were noted at testing intervals, conventional FRBC materials overall demonstrated greater flexural strength than the self-adhesive and compomer materials. Three self-adhesive materials and the compomer were below recommended ISO 4049:2019 flexural strength values at 24 h with another after 6 months storage. Conventional FRBC materials, except at 1 month, overall demonstrated increased flexural modulus than the self-adhesive FRBC materials. Although results were material dependent, conventional FRBC materials demonstrated overall greater flexural mechanical properties as compared to the self-adhesive FRBC materials and the compomer evaluated.

Removable Pressure-Sensitive Adhesives Based on Acrylic Telomer Syrups

Removable pressure-sensitive adhesives (PSAs) are used in the production of self-adhesive materials such as protective films, masking tapes or biomedical electrodes. This work presents a new and environmentally friendly method of obtaining this type of adhesive materials, i.e., photochemically induced free radical telomerization. Adhesive binders to removable PSAs, i.e., the photoreactive acrylic telomer syrups (ATS) were prepared from n-butyl acrylate, acrylic acid, and 4-acrylooxybenzophenone. Tetrabromomethane (CBr4) or bromotrichloromethane (CBrCl3) were used as the telogens. ATS was modified with unsaturated polybutadiene resin and a radical photoinitiator. Adhesive compositions were coated onto a carrier and UV cross-linked. The effects of the chemical nature of telomers (i.e., terminal Br or Cl atoms) and their molecular weight (K-value), as well as the cross-linking degree on adhesive properties of PSAs, were studied. It was found that with the increase in telogen content in the system, the dynamic viscosity of ATS and K-value of acrylic telomers decrease, and the conversion of monomers increases. CBr4 turned out to be a more effective chain transfer agent than CBrCl3. Moreover, telomers with terminal Br-atoms (7.5 mmol of CBr4), due to slightly lower molecular weights and viscosity, showed a higher photocrosslinking ability (which was confirmed by high cohesion results at 20 and 70 °C, i.e., >72 h). Generally, higher values of the temperature at which adhesive failure occurred were noted for PSAs based on ATS with lower telogen content (7.5 mmol), both CBr4 and CBrCl3. The excellent result for removable PSA was obtained in the case of telomer syrup Br-7.5 crosslinked with a 5 J/cm2 dose of UV-radiation (adhesion ca.1.3 N/25 mm, and cohesion > 72 h).

Study of Applying Naturally Occurring Mineral Materials for Silicone Pressure-Sensitive Adhesives

Silicones are commonly used as adhesives when high-quality materials are required due to harsh environmental conditions such as high temperature, humidity, etc. To ensure high resistance to environmental conditions, including high temperatures, modifications of silicone adhesives are made using fillers. The characteristics of a modified silicone-based pressure-sensitive adhesive with filler are the focus of this work. Functionalized palygorskite was prepared in this investigation by grafting 3-mercaptopropyltrimethoxysilane (MPTMS) onto palygorskite (palygorskite-MPTMS). The palygorskite was functionalized using MPTMS under dried conditions. FTIR/ATR spectroscopy, thermogravimetric analysis, and elemental analysis were all used to characterize the obtained palygorskite-MPTMS. MPTMS loading onto palygorskite was also proposed. The results demonstrated that palygorskite's initial calcination favors the grafting of functional groups on its surface. New self-adhesive tapes based on palygorskite-modified silicone resins have been obtained. This functionalized filler allows for the improvement of the compatibility of palygorskite with specific resins for application in heat-resistant silicone pressure-sensitive adhesives. The new self-adhesive materials showed increased thermal resistance while maintaining good self-adhesive properties.

Influence of Acid-Modified Clinoptilolite on the Self-Adhesive Properties of Silicone Pressure-Sensitive Adhesives.

The preparation of a new "eternally alive adhesive" based on silicone pressure-sensitive adhesives with clinoptilolite is presented. Neat and acid-modified (i.e., treated with sulfuric acid (VI)) clinoptilolite was used. The effect of clinoptilolite acid treatment on the adhesive properties of pressure-sensitive adhesive tapes was tested. The obtained tapes exhibited increased thermal resistance when compared to the reference tapes. Despite introducing the filler, the pressure-sensitive adhesive tapes maintained good functional properties. The new self-adhesive materials show promising implementation potential where increased thermal resistance is required.

Organophilized Montmorillonites as Fillers for Silicone Pressure-Sensitive Adhesives.

In the presented work, organophilized montmorillonites (OMMT) with selected quaternary ammonium compounds (QAC) with different chemical structure ((trioctylmethylammonium chloride-A336, dimethyloctadecyl[3-trimethoxysilyl)propyl]ammonium chloride-D, cetyltrimethylammonium bromide-CTAB, 2-methacryloxyethyltrimethylammonium chloride-MOA) were obtained and used as fillers for physically modified silicone pressure-sensitive adhesives (Si-PSA). Before OMMT addition into Si-PSA matrix, they were analyzed via TGA and XRD techniques. Type of chemical structure of QAC affected d-spacing of OMMT. New self-adhesive materials were obtained based on prepared Si-PSA compositions by adding the obtained fillers to the polymer matrix. New tapes exhibit a good level of useful properties as adhesion, cohesion, and tack-the values did not change or slightly decreased; in addition, the tapes with addition of OMMT showed high thermal resistance reaching the measuring limit of the test equipment-to 225 °C.

Mechanical Stability of Self-Adhesive/Ion-Releasing Resin Composites

The purpose of this study was to assess the effects of water storage on the surface microhardness (VHN) and fracture toughness (K1C) of two self-adhesive restorative materials compared to traditional resin composite and resin-modified glass ionomer cement (RMGIC) restorative materials. Methods: Two self-adhesive materials (Activa and Vertise Flow), a nonflowable composite (Filtek Z250), and an RMGIC (Fuji II) were evaluated. Hardness measurements (n = 12) were recorded at three time intervals: (i) one-hour post-irradiation; (ii) after one day of storage in water at 37 °C; and (iii) after 90 days of storage in water at 37 °C. Fracture toughness (K1C) measurements (n = 12) were conducted after one day of storage in water at 37 °C and 90 days of storage in water at 37 °C. ANOVA and Tukey post hoc tests were used for statistical analysis. Results: Baseline VHN data were 38.2–58.3, decreasing significantly to 28.8–55.6 following 90 days of water storage. The Filtek Z250 had the highest VHN before and after storage, while the Activa had the lowest. KIC values varied between 0.98–1.32 MPa·m0.5. The highest value was for the Filtek Z250 while the Fuji II showed the lowest value (after both 1 and 90 days of storage in water). However, KIC values decreased significantly after storage, except for the Fuji II. Conclusion: Self-adhesive/ion-releasing resin composites were negatively affected by water storage. Material reinforcements are possible future areas to explore.

Alternatives to amalgam: Is pretreatment necessary for effective bonding to dentin?

The aim of this study was to determine whether pretreatment of the dentin surface is beneficial or not by analysis of the bond strengths of four self-adhesive restoratives and four restoration materials where pretreatment of dentin was necessary. Bovine incisors (n=160) were ground flat on the labial surfaces to expose dentin using a grinder and silicon carbide (SiC) abrasive papers under running water. Between preparation and bonding procedures, the crowns were stored in Chloramine-T solution at 4°C. Eight different restorative materials were studied: Activa BioActive (ABA), Cention Forte (CNF), Ceram.x Spectra ST (CXS), Riva self-cure (RSC), Equia Forte (EQF), Fuji II LC (FJI), Ketac Molar (KTM), Surefil one (SFO). Four materials required pretreatment of the dental hard tissue before placement, whereas the other four were self-adhesive (no pretreatment). The specimens were mounted vertically in plaster. A preload of 5N was applied and the subsequent cross-head speed was 0.8mm/min. Shear bond strengths (MPa) were calculated as the failure load divided by the bonding area. Failure modes were recorded as adhesive, cohesive or pretest. Data were statistically analyzed via ordinal regression for inference and Tukey's method to adjust for multiple comparisons. All computations were done using R version 4.1.2 (R Core Team 2021). Smax (failure stress in MPa) of the combined groups with pretreatment were significantly higher than the self-adhesive materials. The highest frequency of pretest-failure was seen with FJI. Glass-ionomer cements without pretreatment were the only restoratives with pretest failures. Amongst materials without pretreatment, SFO had the highest bond strengths. The further reduction of the placement steps for materials used as an amalgam alternative, namely the omission of pretreatment of the dentin, results in these self-adhesive materials having lower bond strengths than materials that require pretreatment of the dentin.

Influence of Nanoclay on the Thermo-Mechanical Properties of Silicone Pressure-Sensitive Adhesives.

This research was carried on newly obtained innovative materials-self-adhesive one-sided tapes based on silicone pressure-sensitive adhesives. In order to obtain tapes, the stable adhesive composition was subjected to physical modification by incorporating into it various amounts of selected silicon fillers. The produced pressure-sensitive adhesives were tested for viscosity and thermogravimetric analysis, as well as the manufactured tapes; i.e., peel adhesion, tack, cohesion at room and elevated temperature, SAFT test (shear adhesive failure temperature), and shrinkage. The prepared self-adhesive tapes retained their self-adhesive properties at a level close to the initial level while increasing the thermal resistance by 70-75 °C, reaching the level of 220-225 °C. The new self-adhesive materials have application potential and can be used as a material for special applications in the field of electrical engineering and heavy industry.

Influence of cleaned granite dust on the properties of silicone pressure-sensitive adhesives

The influence of addition cleaned granite dust on self-adhesive products, such as self-adhesive tapes based on silicone pressure-sensitive adhesives was presented. The new way of waste management, is a very important issue in the modern world. The obtained self-adhesive materials were tested both in terms of the properties of adhesive compositions (pot-life test) as well as the influence on the operational parameters of the obtained self-adhesive tapes, such as adhesion, cohesion, stickiness or shrinkage. The obtained results are presented in the paper below.

Fracture and viscoelastic behavior of novel self-adhesive materials for simplified restoration concepts

ObjectiveThe aim of the study was to offer a comparative perspective on the mechanical and viscoelastic behavior of currently developed materials for simplified restoration concepts. These materials have not yet been clearly assigned whether they are complex hybrids of already known material categories or new material classes. MethodsA dual-cured, bulk-fill, bioactive resin-based composite (alkasite), a resin-modified glass ionomer cements (RM-GIC) with novel polymerizable acid polymers, and a glass ionomer cement (GIC) with improved adaptation to an acidic environment were compared with regard to their macro-mechanical parameters (3-point bending test, 3-PBT), fracture mechanism, quasi-static and viscoelastic behaviour (instrumented indentation test, IIT), morphology and structural appearance of the filler system (SEM analysis). The influence of surface finishing was quantified on the outcome of the 3-PBT, while the influence of aging and frequency was monitored on the outcome of the IIT. One and multiple-way analysis of variance (ANOVA) with Tukey honestly significant difference (HSD) post-hoc tests (α = 0.05) and Weibull analysis were applied. ResultsSurface finishing strongly influenced the outcome of the 3-PBT for RM-GIC and GIC but not of the alkasite. The highest material reliability (Weibull parameter m) was found with the alkasite, irrespective of the curing mode. Ground specimens showed decrease reliability, except for the alkasite in the light-cured mode. The predominant failure mode originated from sub-surface defects (52.5%), followed by corner (25%), edge (18.1%), and crack arrest (4.4%). The effect of the parameter material on the quasi-static outcome of the IIT was highest on elastic/plastic parameters (p < 0.001; e.g. elastic indentation work, ηP2 = 0.875), was moderate on the Martens Hardness (ηP2 = 0.420), and was low on the Vickers hardness (ηP2 = 0.218). The viscoelastic parameters, in particular the loss factor (tan δ) allow a clear documentation of the ongoing acid-base setting reaction during aging of one month, which was more pronounced in the GIC than in the RM-GIC. The decrease in tan δ with aging for GIC and RM-GIC reflects the maturation process and increased brittleness, while the increase in tan δ with aging reflects the polymer plasticization in the polymer-based alkasite. ConclusionsThe mechanical and viscoelastic behavior depending on surface refinement, aging and frequency clearly allow to classify the currently developed materials for simplified restoration concepts into known material categories such as RBCs (alkasite), RM-GIC or GIC.

Evaluation of the Water Sorption and Solubility Behavior of Different Polymeric Luting Materials.

Objective: The study evaluated the water sorption (WSP) and water solubility (WSL) characteristics of different luting agents over a 180-day water storage period. Materials and Methods: Nine luting materials, i.e., conventional resin cement: Panavia F (PF), Rely X ARC (RA), self-adhesive resin cement: Rely X Unicem (RU), Breez (BZ), Maxcem Elite (MX), BisCem (BC) and resin-modified glass ionomer cement: FujiCem (FC), FujiPlus (FP) Rely X luting plus (RL) were assessed and fifty-two-disc specimens of each material were fabricated. All specimens were desiccated until a constant weight (W0) was reached. Thirteen specimens for each luting material were then randomly assigned to one of the four water immersion periods (7, 30, 90, and 180 days). After each period, the specimens were removed from the water and weighed to get W1. The samples were again desiccated for a second time and W2 was measured. Both WSP and WSL were determined by the following equations: WSP (%) = (W1 − W2) × 100/W0 and WSL (%) = (W0 − W2) × 100/W0. Assessments were performed following ISO standards. ANOVA was used to assess the effect of luting agent and time period on water sorption and solubility. Pair-wise comparisons were adjusted using Tukey’s multiple comparison procedure. A significance level of 0.05 was used for all statistical tests. Results: The highest mean WSP and WSL (WSP/WSL) were demonstrated by resin-modified glass-ionomers (RL 18.32/3.25, FC 17.08/4.83, and FP 14.14/1.99), while resin luting agents showed lower WSP and WSL results (PF 1.6/0.67 and RA 1.76/0.46), respectively. The self-adhesive agents exhibited a wide range of WSP and WSL values (RU 1.86/0.13, BZ 4.66/0.93, and MX 3.68/1.11). Self-adhesive cement showed lower WSP and WSL compared with the resin-modified glass-ionomers (p < 0.05). All the materials reached equilibrium after 90-days. Conclusions: Resin-based luting materials have the lowest sorption and solubility. Rely X Unicem self-adhesive luting materials were comparable to resin luting materials for WSL and WSP. Resin-modified glass-ionomer showed the highest water sorption and solubility compared with both resin and self-adhesive materials.

Effect of Water Storage on Hardness and Interfacial Strength of Resin Composite Luting Agents Bonded to Surface-Treated Monolithic Zirconia.

Background: Durable bonding between resin composite luting agents (CLA) and zirconia is still a matter of controversy. The purpose of this study was to evaluate the effect of water storage on hardness and interfacial strength of three CLA, a non-adhesive (Multilink Automix/ML), an adhesive (Panavia F 2.0/PF) and a self-adhesive (PermaCem 2.0/PC), bonded to polished (CL) and grit-blasted (AL: 50 μm alumina, SJ: Sil-Jet + Monobond Plus silane) monolithic zirconia surfaces. Methods: CLA specimens (n = 5/cement, condition) were prepared, stored under dry conditions or immersed in water, and Vickers hardness (VH) measurements were obtained at 1 h, 24 h, 1 week and 3 weeks intervals. Optical profilometry was used to determine the roughness parameters (Sa, Sz, Sdr, Sci) of zirconia surfaces (n = 5/treatment). A shear strength test (SBS, n = 10 × 2/cement) was performed to assess the strength and fractography of the cements bonded to zirconia after isothermal water storage and thermal-cycling (TC). Results: PF demonstrated significantly lower VHN after water storage at all time intervals, PC at 1 w, 3 w and ML at 3 w. SJ and AL showed significantly higher values from CL in all roughness parameters. Weibull analysis revealed the following significance in σο ranking within the same material: AL, SJ, ALTC > SJTC, CL > CLTC (PF); SJ, SJTC, AL, ALTC > CL, CLTC (PC) and SJ, SJTC > AL > ALTC > CL, CLTC (ML). Within the same surface treatment subgroups, the significance in σo ranking was PC, ML > PF (before/after TC) for SJ; PC > PF > ML (before TC), PC, PF > ML (after TC) for AL, and PC > PF > ML (before/after TC) for CL. For the m ranking, the only significant difference within each material group was found in PC (AL > ALTC) and for the same surface treatment in AL (PC > ML). Conclusion: There are significant differences in the water plasticization susceptibility of the CLA tested; the materials with adhesive monomers were the most affected. Tribo-chemical silica coating combined with a silane coupling agent was the most efficient bonding treatment for the non-adhesive and the self-adhesive materials. The adhesive CLA performed better on alumina-blasted than on tribo-chemically coated surfaces.

Ocena laboratoryjna materiałów używanych do uszczelniania zagłębień anatomicznych w zębach stałych niedojrzałych

Introduction. Pit and fissure sealing is highly efficient in caries prevention. New types of composite materials – self-adhesive and bulk fill materials – are interesting alternatives to standard resin-based sealants. Their specific features may contribute to the clinical success of the sealing procedure. The requirement for a successful procedure is an adequate seal of the material to prevent bacterial microleakage. Aim. The aim of this study is the laboratory evaluation of the degree of filling of fissures by the tested materials and the occurrence of gaps between the materials and enamel. Material and methods. Fissures of 15 permanent third molars were sealed with the following materials: Helioseal F (Ivoclar Vivadent), Vertise Flow (Kerr) and SDR (Dentsply Sirona) with XP Bond (Dentsply Sirona). The specimens were embedded in epoxy resin and cut. Images were taken using a scanning electron microscope. An evaluation of the degree of fissure filling and material adaptation was performed in a graphic software. Statistical analysis was performed. Results. A total of 22 samples were evaluated: 7 Helioseal F, 7 Vertise Flow and 8 SDR. SDR had the highest percentage of fissure filling depth (0.808), followed by Vertise Flow (0.614) and Helioseal F (0.602). The highest percentage of fissure fill area was characterized by SDR at 0.938, followed by Helioseal F at 0.872 and Vertise Flow at 0.799. No statistically significant differences were observed between the results. The percentage of inadequate material adaptation was 0 for SDR, 0.069 for Vertise Flow and 0.149 for Helioseal F. There was a statistically significant difference between Helioseal F and SDR material. Conclusions. The degree of fissure filling by all tested materials is comparable, while the degree of adaptation of the materials to the enamel surface is statistically different when comparing SDR to Helioseal F, in favor of SDR.

Surface degradation evaluation of different self-adhesive restorative materials after prolonged energy drinks exposure.

To evaluate the effects of energy drinks and soft beverages on the surface degradation of different self-adhesive materials. A 156 disc shaped specimens of each of the following materials were prepared: Alkasite (Cention N, CN), High viscozity glass ionomer (Equia Forte, EF), Glass Carbomer (GCP Fill, GC) (n = 52). After specimen preparations, baseline surface roughness measurements were done using a 3D non-contact optical profilometer. Then, specimens were subdivided into 4 subgroups (n = 13) and stored in petri dish containing Red Bull; Burn; Coca-Cola and Distilled water. The surface roughness of the specimens were measured after 1-day, 1-week, and 1-month of immersion in beverages. It was observed that 1-month Red Bull immersion revealed the highest roughness difference (ΔRa) for each self-adhesive restorative material and this was followed by Burn. Whereas, the lowest ΔRa values were observed after 1-day coke and distilled water immersion in all tested material groups (P < 0.05). Coke and distilled water presented the energy drinks' 1-day immersion affect, after 1-week immersion (P < 0.05). The energy drinks have a substantially damaging effect on roughness of self adhesive materials compared with soft drinks and distilled water; and this effect is increasing with exposure duration.

Editorial: On our way to Self-Adhesive Restorative Materials 2.0.

Editorial: On our way to Self-Adhesive Restorative Materials 2.0.

Bond Strength of Self-Adhesive Restorative Materials Affected by Smear Layer Thickness but not Dentin Desiccation.

To use shear bond strength (SBS) testing to determine the effect of surface moisture and smear layer thickness on the adhesion of self-adhesive restorative materials and a universal adhesive. One single-step self-etch universal adhesive, Prime & Bond Active (PA), was used to bond Ceram.x Spectra ST HV composite resin to dentin and enamel using the self-etching technique. Three commercially available restorative materials and one newly developed material with self-adhesive properties, Activa (A), Fuji II LC(F), Equia Forte (E), and ASAR-MP4 (S), respectively, were also bonded to enamel and dentin prepared moist and dry and to dentin prepared with a thick smear layer. Shear bond testing was performed using an Ultradent bonding apparatus. The universal adhesive generated the highest SBS to dentin and enamel, followed by the newly developed material. None of the materials tested were significantly affected by the moisture conditions on enamel or dentin. The thickness of smear layer significantly affected SBS to dentin for S, F, and E. However, S and F still exhibited higher shear bond strength to dentin with the thicker smear layer compared to the other self-adhesive materials. Only the universal adhesive in self-etch mode was not affected by the thicker smear layer and maintained significantly higher SBS. None of the materials tested were affected by bonding to overdried dentin or enamel. All of the self-adhesive materials exhibited lower SBS to specimens with a thicker smear layer. The newly developed material ASAR-MP4 compared favorably to the other self-adhesive materials tested under all test conditions.