Adhesive Cement Research Articles

Effect of water glass treatment for zirconia and silane coupling on bond strength of resin cement.

To evaluate the ability of the water glass treatment to penetrate zirconia and improve the bond strength of resin cement. Water glass was applied to zirconia specimens, which were then sintered. The specimens were divided into water-glass-treated and untreated zirconia (control) groups. The surface properties of the water-glass-treated specimens were evaluated using surface roughness and electron probe micro-analyser (EPMA) analysis. A resin cement was used to evaluate the tensile bond strength, with2 and without a silane-containing primer. After 24h in water storage at 37°C and thermal cycling, the bond strengths were statistically evaluated with t-test, and the fracture surfaces were observed using SEM. The water glass treatment slightly increased the surface roughness of the zirconia specimens, and the EPMA analysis detected the water glass penetration to be 50μm below the zirconia surface. The application of primer improved the tensile bond strength in all groups. After 24h, the water-glass-treated zirconia exhibited a tensile strength of 24.8 ± 5.5MPa, which was significantly higher than that of the control zirconia (17.6 ± 3.5MPa) (p < 0.05). After thermal cycling, the water-glass-treated zirconia showed significantly higher tensile strength than the control zirconia. The fracture surface morphology was mainly an adhesive pattern, whereas resin cement residue was occasionally detected on the water-glass-treated zirconia surfaces. The water glass treatment resulted in the formation of a stable silica phase on the zirconia surface. This process enabled silane coupling to the zirconia and improved the adhesion of the resin cement.

Bond Strength of Milled and Printed Zirconia to 10-Methacryloyloxydecyl Dihydrogen Phosphate (10-MDP) Resin Cement as a Function of Ceramic Conditioning, Disinfection and Ageing.

This study aimed to assess the suitability of printed zirconia (ZrO2) for adhesive cementation compared to milled ZrO2. Surface conditioning protocols and disinfection effects on bond strength were also investigated. ZrO2 discs (n = 14/group) underwent either alumina (Al2O3) airborne particle abrasion (APA; 50 µm, 0.10 MPa) or tribochemical silicatisation (TSC; 110 µm Al2O3, 0.28 MPa and 110 µm silica-modified Al2O3, 0.28 MPa), followed by disinfection (1 min immersion in 70% isopropanol, 15 s water spray, 10 s drying with oil-free air) for half of the discs. A resin cement containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) was used for bonding (for TSC specimens after application of a primer containing silane and 10-MDP). Tensile bond strength was measured after storage for 24 h at 100% relative humidity or after 30 days in water, including 7500 thermocycles. Surface conditioning significantly affected bond strength, with higher values for TSC specimens. Ageing and the interaction of conditioning, disinfection and ageing also impacted bond strength. Disinfection combined with APA mitigated ageing-related bond strength decrease but exacerbated it for TSC specimens. Despite these effects, high bond strengths were maintained even after disinfection and ageing. Adhesive cementation of printed ZrO2 restorations exhibited comparable bond strengths to milled ZrO2, highlighting its feasibility in clinical applications.

Enhancing Aesthetic and Structural Integrity in Necrotic Permanent Incisor with Open Apex: A Case Report

Traumatic injuries in immature teeth often lead to complications in endodontic treatment due to difficulty in managing the open apex. Also, the restoration of these teeth poses significant challenges due to thin dentin walls, high configuration factors, and other biomechanical and adhesive issues. Standard fibre posts are often not suited for flared root canal preparations, leaving excessive cement space between the post and the tooth structure. To reduce postoperative complications (e.g. root fracture), reinforcement of radicular dentin becomes mandatory after endodontic treatment. The reinforcement of the canal can be done using a fibre post relined with composite resin. Direct anatomical posts offer a promising alternative that minimises the risk of debonding. This case report details the use of platelet rich fibrin as a internal matrix and how mineral trioxide aggregate can be used to form an immediate apical seal for apexification and a custom fiber post technique for reinforcing an immature maxillary central incisor in an 18-year-old patient. Keywords - Adhesive cement, Apical seal, Dentin reinforcement, Esthetics, Fiberglass, MTA, Post and core technique

Influence of mechanochemical treatment and oxygen inhibited layer on the adhesion of self-adhesive resin cement to bulk-fill composite resin

Influence of mechanochemical treatment and oxygen inhibited layer on the adhesion of self-adhesive resin cement to bulk-fill composite resin

Marginal Leakage in Interfaces Formed by Bovine Dentin and Adhesive Cements Applied with Different Bonding Techniques

Objectives: The aim of this in vitro study was to evaluate the marginal microleakage in interfaces formed by bovine dentin and adhesive cements applied with different bonding techniques. Materials and Methods: Thirty bovine teeth dentin blocks measuring 5 mm x 5 mm x 1 mm were made with one side completely in dentin substract (20 mm2). The dentin blocks were randomly divided into three groups according to the cementation technique used: CTS+RX (conventional 3-step adhesive + dual-activation resin cement), SBS+RX (single-bottle self-etching adhesive + dual-activation resin cement), and SAC (self-adhesive cement). A photopolymerizable composite resin block with the same dimensions was fixed on the dentin block according to the instructions for each adhesive technique. The dentin-composite resin blocks made with each adhesive technique were separated into subgroups (n = 5) for 7 days (control) and for 6 months of water storage. After each period, the blocks were individually immersed in test tubes containing neutral methylene blue dye for 2 hours. The samples were washed, dried, and evaluated with a stereoscopic magnifying glass, and the amount of infiltrated pigment was analyzed using spectrophotometry (Beckman DU 65). The data were submitted to two-way ANOVA and Tukey’s test (5%). Results: Microleakage level for the conventional 3-step or self-etching technique remained similar for 7 days (18 ± 25 and 43 ± 45 μm, respectively) or 6 months (42 ± 55 and 52 ± 87 μm, respectively). The self-adhesive technique showed higher microleakage levels for 7-day (263 ± 98 μm) and 6-month periods (441 ± 226 μm) compared to other adhesive techniques. There was a statistically significant difference between evaluation times only for the self-adhesive technique. Conclusions: Higher microleakage levels by storage in water occurred with the self-adhesive technique in both evaluation periods. Clinical Relevance: The different microleakage levels promoted at the dentin-composite resin interface should be considered in adhesive clinical procedures in relation to long-term use.

Barnacle cement protein as an efficient bioinspired corrosion inhibitor

To prevent corrosion damage in aggressive environments such as seawater, metallic surfaces are coated with corrosion inhibitors usually made of organic molecules. Unfortunately, these inhibitors often exhibit environmental toxicity and are hazardous to natural habitats. Thus, developing greener and effective corrosion inhibitors is desirable. Here, we present an alternative green inhibitor, the recombinant protein rMrCP20 derived from the adhesive cement of the barnacle Megabalanus rosa and show that it efficiently protects mild steel against corrosion under high salt conditions mimicking the marine environment. We reveal that these anti-corrosion properties are linked to the protein’s biophysical properties, namely its strong adsorption to surfaces combined with its interaction with Fe ions released by steel substrates, which forms a stable layer that increases the coating’s impedance and delays corrosion. Our findings highlight the synergistic action of rMrCP20 in preventing corrosion and provide molecular-level guidelines to develop alternative green corrosion inhibitor additives.

Adhesive Cementation of CAD/CAM Silica-based Ceramics: Effect of Adhesive Type and Long-term Aging on the Bond Strength to Composite Cement.

To investigate the effect of adhesive type and long-term aging on the shear bond strength (SBS) between silica-based ceramics and composite cement (CC). Lithium-silicate (LS), feldspathic (FD) and polymer-infiltrated ceramic (PIC) blocks were sectioned (10 x 12 x 2 mm) and divided into 24 groups considering the factors: "ceramics" (LS, FD, and PIC), "adhesive" (Ctrl: without adhesive; 2SC: 2-step conventional; 3SC: 3-step conventional; 1SU: 1-step universal), and "aging" (non-aged or aged [A]). After the surface treatments, CC cylinders (n = 15, Ø = 2 mm; height = 2 mm) were made and half of the samples were subjected to thermocycling (10,000) and stored in water at 37°C for 18 months. The samples were submitted to SBS testing (100 kgf, 1 mm/min) and failure analysis. Extra samples were prepared for microscopic analysis of the adhesive interface. SBS (MPa) data was analyzed by 3-way ANOVA and Tukey's test (5%). Weibull analysis was performed on the SBS data. All factors and interactions were significant for SBS (p<0.05). Before aging, there was no significant difference between the tested groups and the respective control groups. After aging, the LS_1SU (22.18 ± 7.74) and LS_2SC (17.32 ± 5.86) groups exhibited significantly lower SBS than did the LS_Ctrl (30.30 ± 6.11). Only the LS_1SU group showed a significant decrease in SBS after aging vs without aging. The LS_1SU (12.20) group showed the highest Weibull modulus, which was significantly higher than LS_2SC_A (2.82) and LS_1SU_A (3.15) groups. No type of adhesive applied after silane benefitted the long-term adhesion of silica-based ceramics to CC in comparison to the groups without adhesive.

Investigation of adhesive shear strength of universal adhesives for fixing ceramic braces

Relevance. At the present stage, the choice of high-quality adhesive material is an important task of dentistry. The choice of the ideal adhesive material remains an urgent task to this day.The aim of the study was to study in laboratory conditions the adhesive shear strength for fixing ceramic braces of a universal adhesive system containing 3D-SR monomer (Universal Bond II (Tokuyama Dental)) and adhesive cement ESTECEM II PLUS (Tokuyama Dental) before and after thermal cycling, with and without the use of varnish.Materials and methods. For the preparation of samples, removed teeth without carious lesions and large fillings were used. Samples of 60 teeth were divided into 2 groups (n=30) with and without varnish. In each group, the adhesive shear strength was studied before and after thermal cycling (n=15). The following materials were used: two-component self-curing dental adhesive system Universal Bond II (Tokuyama Dental), varnish SHIELD FORCE PLUS (Tokuyama Dental), adhesive fixing cement double curing ESTECEM II PLUS (Tokuyama Dental). Tests of the adhesive shear strength of the prepared samples were carried out on a universal testing machine «SYNTHEZ 5» at a traverse speed of 5 mm/min according to the methodology of GOST R 56924-2016 (р. 7.15).Results. The adhesive strength index of the control group (before thermal cycling) was 4.33±1.28 MPa, in the main subgroup (after thermal cycling) 3.48±0.81 MPa. The presence of varnish on the enamel surface did not affect the adhesive strength of the bonding of the bracket system and tooth tissue and amounted to 4.50±0.25 MPa and 3.14±0.82 MPa, respectively (p= 0.0005).Conclusions. The presence of varnish on the enamel surface did not affect the adhesive strength of the connection of the bracket systems with tooth tissues in the control (before thermal cycling) and the main (after thermal cycling) subgroups (p≤ 0.05). The adhesive strength index in the control subgroups (before thermal cycling) and the main ones (after thermal cycling) of both groups differed slightly. Thermal cycling reduces the adhesive strength of braces with tooth tissues when using universal adhesive Universal Bond II (Tokuyama Dental) (p≤ 0.05).

Is adhesive bonding with high and low viscosity cements able to revert the negative effect of machining on the fatigue behavior of lithium disilicate glass-ceramic?

The aim of this study was to evaluate the fatigue behavior of adhesively cemented machined and polished lithium disilicate discs and compare the influence of the resin cement viscosity used to bond the ceramics to dentin analog substrate. Disc-shaped specimens (n = 15, Ø = 12 mm; thickness = 1.3 mm) of CAD-CAM lithium disilicate (IPS e.max CAD, Ivoclar Vivadent) were prepared and divided according to processing and surface finishing (machining (M) – CEREC inLab; and polishing (P) – control) and cement viscosity (high (H) and low (L)). The specimens were treated with self-etching primer and adhesively cemented (Variolink N Base + High or Low viscosity catalyst, Ivoclar Vivadent) to dentin analog discs (Ø = 12 mm; thickness = 2.2 mm). The cemented assemblies were subjected to fatigue testing using a step-stress approach (500−1500 N; step-size of 100 N; 10,000 cycles per step; 20 Hz). Weibull statistics were conducted on fatigue data (95 % CI). Fractographic and topographic analyzes were also performed on a scanning electron microscope (SEM). Considering the same viscosity, machined groups presented statistically lower characteristic fatigue failure load (N) (FFL0 MH 1192 [1111–1278]; ML 1105 [1077–1134]) than their polished controls (FFL0 PH 1350 [1279–1424]; PL 1333 [1276–1392]). No differences were found between cement viscosities, regardless of surface characteristic. It is well known that CAD-CAM machining impairs mechanical performance of lithium disilicate glass-ceramics. Adhesive cementation was not able to revert this negative impact, regardless of cement viscosity. Cement viscosity did not affect the fatigue results.

Preheated acid associated with silane and electric current in the adhesion of the resin cement to ceramic.

This study verified the effect of the combination of preheated hydrofluoric acid/silane/electric current in the adhesion of the resin cement to ceramic. IPS E.max Press ceramic discs embedded in PVC rigid tubes were divided into four groups associating preheated hydrofluoric acid and silane applied with electrical current (n=10): Ha+S (Heated acid + silane); Ha+S+Ec (Heated acid + silane + electrical current); A+S (Acid + silane) and A+S+Ec (Acid + silano + electrical current). Resin cement/ceramic samples were stored in water at 37°C for 24h. After storage, they were submitted to the microshear test, fracture analysis, and contact angle at 24h or after thermocycling (10,000 cycles/5-55ºC). Bond strength data were evaluated by two-way ANOVA. For comparison between evaluation times (24h or thermocycling) was applied unpaired t-test. A significance post-hoc test of p=0.05 was assumed for analyses and graphs (GraphPad Prism 9.0 software). At 24h, the microshear strength showed similar values between Ha+S, Ha+S+Ec, and A+S+Ec groups, while A+S showed the lowest value with a statistical difference. After thermocycling, Ha+S and Ha+S+Ec were similar, as well as A+S and A+S+Ec. There was a significant difference in all groups comparing 24h (highest value) with after thermocycling (lowest value). Adhesive fracture was predominant in all groups and evaluation times. Ha+S and A+S groups showed higher contact angle values compared to the Ha+S+Ec and A+S+Ec with lower values. In conclusion, the association of preheated hydrofluoric acid/silane applied or not with electric current promoted different microshear strength values, fracture types, and contact angles in the resin cement/ceramic bond.

Shear Bond Strength of Veneering Composite Versus Different Polyetheretherketone Materials after Various Surface Treatments: An In-vitro Study

Introduction: Polyetheretherketone, also known as PEEK, is a semicrystalline thermoplastic material with many advantages. Since its grey material, it has to veneering with composite resin to enhance its aesthetic appeal. Bonding PEEK and composite veneers poses challenges due to its inert surface. Aim: To assess and compare the Shear Bond Strength (SBS) between various polyetheretherketone materials and veneering composites following various surface treatments. Materials and Methods: The in-vitro study was conducted at KSR Dental College and Hospital in Tiruchengode, Tamil Nadu, India, over a period of three months from December 2022 to February 2023. A total of 108 PEEK discs were prepared for the study, divided into three groups: unfilled PEEK, 30% carbon reinforced PEEK, and 10% carbon + 10% graphite + 10% Polytetrafluoroethylene (PTFE) reinforced PEEK. The specimens underwent different surface treatments, including no treatment, sandblasting with 110 um alumina particles, and acid etching with 98% sulphuric acid. Additionally, 108 composite discs were prepared and bonded to the PEEK specimens using adhesive and resin cement. The bonded specimens were immersed in distilled water for 24 hours, and the Shear Bond Strength (SBS) was determined using a universal testing machine. Statistical analysis was performed using one-way ANOVA, and mean values were compared using posthoc tests. Results: The results indicated significant variation in SBS among the three groups without treatment (p=0.011) and after sandblasting with 110 um alumina (p=&lt;0.001). The 30% carbon reinforced PEEK exhibited the highest SBS regardless of the surface treatments. Conclusion: Among the tested materials, 30% carbon reinforced PEEK demonstrated the highest SBS, regardless of the surface treatments. Acid etching yielded the highest SBS among the various surface treatments, irrespective of the type of PEEK material used.

EVALUATION OF BOND STRENGTH BETWEEN DIFFERENT SYSTEMS FOR ADHESIVE CEMENTATION TO FELDSPATHIC PORCELAIN AND ZIRCONIUM OXIDE

Introduction: New systems for adhesive cementation have been increasingly developed and used in daily clinical practice for the cementation of ceramic prostheses. Differences in the chemical composition of various system components can influence the bond strength between the resin cement and the ceramic. Objective: This study aims to evaluate the bond strength between two ceramic systems—feldspathic porcelain and yttria-stabilized zirconium oxide—and three different systems for adhesive cementation: Rely X ARC, Multilink System, and Rely X UCem. Methodology: Thirty discs of Noritake feldspathic porcelain and thirty discs of zirconium oxide ceramic were fabricated, each measuring 7.5 mm in diameter by 3.0 mm in thickness, according to the manufacturers’ instructions. The discs were polished on a mechanical polisher with water sandpaper ranging from 320 to 1500 grit and embedded in ½ inch PVC tubes with self-curing acrylic resin. The feldspathic porcelain discs were conditioned with 10% hydrofluoric acid for 120 seconds, and the zirconium oxide discs were sandblasted with 40 psi alumina for 10 seconds at 10 mm. All discs were then washed and placed in an ultrasonic bath with distilled water for 10 minutes. The cementation systems were applied according to the manufacturers’ instructions (n=10) on an adhesion area of 5.0 mm in diameter, delimited by a tripartite metal matrix. The samples underwent 1,000 thermal cycles ranging from 5°C to 55°C. Shear bond strength tests were performed on an EMIC DL2000 testing machine with a 20 kN load cell and a speed of 0.5 mm/min. The mean values of the groups were as follows (in MPa): Feldspathic with Rely X ARC (G1) 6.21; Feldspathic with Multilink (G2) 8.98; Feldspathic with Rely X UCem (G3) 8.15; Zirconium Oxide with Rely X ARC (G4) 0.53; Zirconium Oxide with Multilink (G5) 9.25; Zirconium Oxide with Rely X UCem (G6) 4.37. Data were subjected to one-way ANOVA and Tukey tests. Results: There was no significant difference among the feldspathic porcelain groups. For zirconium oxide, Multilink showed higher bond strength values. Conclusion: The bond strength between the cements and feldspathic porcelain exceeded the intrinsic strength of this material, and Multilink showed the highest bond strength values regardless of the ceramic material.

Effect of Thermomechanical Fatigue Loading on the Internal and Marginal Adaptation of Endocrowns Utilizing Different CAD/CAM Restorative Materials

To assess the impact of fatigue loading on the internal and marginal fit of CAD/CAM-fabricated endocrowns for restoring endodontically treated molars using different machinable blocks. A total of 72 mandibular first molars were prepared using a standardized method and were divided into four groups (n = 18), each restored with a different CAD/CAM material: group V = polymer-infiltrated ceramic (Vita Enamic); group K = partially stabilized tetragonal zirconia (Katana); group E = lithium disilicate ceramic (IPS e.max CAD; and group B = polyetheretherketone (BioHPP). Endocrowns were subjected to thermomechanical fatigue loading. Internal and marginal adaptation of the endocrowns were examined at 66 points using the sectioning technique and a stereomicroscope. Data were analyzed using one-way ANOVA and Tukey post hoc test (α = .05). Statistical tests showed that adhesive cementation resulted in significantly increased marginal and internal gap values in all regions in all four tested groups (P < .001). After thermomechanical fatigue loading, all regions in groups B and K showed a statistically significant difference, while no significant differences were found in the regions in group V (P > .05). In group E, the marginal (F = 71.00) and pulpal (F = 28.065) regions showed statistically significant differences (P < .001). Polymer-infiltrated ceramics showed the lowest gap even after thermomechanical fatigue loading and may therefore provide enhanced clinical survival of the restored tooth, favoring the use of this material for fabricating endocrown restorations.

Improving the Antibacterial Properties of Dental Bonding Materials Loaded with Silver Compounds.

Biofilm accumulation, the appearance of white spot lesions and the development of secondary caries are the main complications in orthodontic patients. A promising approach to fight this situation is the development of adhesive cements with improved antibacterial properties. The aim of the present study was to evaluate the possibility of improving the antibacterial properties of glass ionomer cements by incorporating different types of antimicrobial compounds without altering their physical and mechanical properties. Different concentrations of silver carbonate (SC) and an inorganic glass with encapsulated silver were added to the glass ionomer cement, as well as chitosan, to achieve synergistic antibacterial activity. Variations in the antibacterial capacity were evaluated using the agar diffusion test; the potential alteration of the physical and mechanical properties of the material was analyzed by the shear bond strength test. SEM characterization and colorimetric evaluation were also conducted. Samples of SC up to 1% and inorganic glass with encapsulated silver up to 5% showed significant improvement in their antibacterial ability without compromising shear strength. The highest antimicrobial activity was observed for Lactobacillus acidophilus, with inhibition zones of 3.8 and 3.1 mm for SC and inorganic glass, respectively. The characterization of the samples did not detect any major structural changes between the different samples. The only group that underwent a noticeable color change was the group with SC. The results show that the incorporation of silver carbonate and inorganic glass with encapsulated silver provided the glass ionomer cement with an antibacterial capacity without compromising the bond strength and without modifying the structure of the material.

Fracture resistance of endodontically treated teeth, restored with two post-core systems in different post space diameters (in vitro study)

BackgroundFracture resistance of post-core restoration depends on the design of the post, post diameter, post length, the type of adhesive cement used along with material of the core. Despite the different studies concerning the effect of post space diameter on the fracture resistance of endodontically treated teeth, more information regarding fracture resistance and the effect of different post space systems/materials and diameters is required.Aim of the studyThis study aimed to evaluate fracture resistance of endodontically treated teeth, restored with two post-core systems in different post space diameters.Materials and methodsTwenty freshly extracted maxillary central incisors were collected for this study. They were randomly divided into four groups according to intracanal post and its diameter. Group GN (glass-fiber post of 10-mm length and 1.3-mm diameter with composite core), group GW (glass-fiber post of 10-mm length and 1.75-mm diameter with composite core), group ZN (custom-made zirconia one-piece post-core of 10-mm length and 1.3-mm diameter) and group ZW(custom-made zirconia one-piece post-core of 10-mm length and 1.75-mm diameter).Fracture resistance for all samples was evaluated using the universal testing machine under a static load. The data was collected and statistically analyzed using One-Way ANOVA test. Modes of failure were assessed using stereomicroscope for each group.ResultsThe highest mean fracture resistance was recorded in group GW (638.7 ± 285.1 N), followed by group ZW (598.5 ± 127.6 N), then GN group (442.8 ± 65.38 N). The lowest mean fracture resistance was recorded in group ZN (435.3 ± 117.3 N). One-Way ANOVA test revealed that there was no statistically significant difference in fracture resistance values among the groups.ConclusionPost space diameter had an impact over the fracture resistance of endodontically treated teeth. Modulus of elasticity of post material had a major effect on the fracture resistance and mode of failure along with the restorability of the restored tooth. However, there was no statistically significant difference among the tested groups.

Effect of surface modification of graphene oxide with a reactive silane coupling agent on the mechanical properties and biocompatibility of acrylic bone cements

Carbon allotrope materials (i.e. carbon nanotubes (CNTs), graphene, graphene oxide (GO)), have been used to reinforce acrylic bone cement. Nevertheless, the intrinsic incompatibility among the above materials produces a deficient interphase. Thus, in this work, the effect of the content of functionalized graphene oxide with a reactive silane on the mechanical properties and cell adhesion of acrylic bone cement was studied. GO was obtained by an oxidative process on natural graphite; subsequently, GO was functionalized with 3-methacryloxypropyltrimethoxysilane (MPS) to enhance the interphase between the graphenic material and acrylic polymeric matrix. Pristine GO and functionalized graphene oxide (GO-MPS) were characterized physicochemically (XPS, XRD, FTIR, and Raman) and morphologically (SEM and TEM). Silanized GO was added into the acrylic bone cement at different concentrations; the resulting materials were characterized mechanically, and their biocompatibility was also evaluated. The physicochemical characterization results showed that graphite was successfully oxidized, and the obtained GO was successfully functionalized with the silane coupling agent (MPS). SEM and TEM images showed that the GO is composed of few stacked layers. Compression testing results indicated a tendency of increasing stiffness and toughness of the acrylic bone cements at low concentration of functionalized GO. Additionally, the bending testing results showed a slightly increase in bone cement strain with the incorporation of GO-MPS. Finally, all samples exhibited cell viability higher than 70%, which means that materials are considered non-cytotoxic, according to the ISO 10993-5 standard.

Attachment discs of the diving bell spider Argyroneta aquatica

To adhere their silk threads for the construction of webs and to fix the dragline, spiders produce attachment discs of piriform silk. Uniquely, the aquatic spider Argyroneta aquatica spends its entire life cycle underwater. Therefore, it has to glue its attachment discs to substrates underwater. Here we show that Argyroneta aquatica applies its thread anchors within an air layer around the spinnerets maintained by superhydrophobic setae. During spinning, symmetric movements of the spinnerets ensure retaining air in the contact area. The flat structure of the attachment discs is thought to facilitate fast curing of the piriform adhesive cement and improves the resistance against drag forces. Pull-off tests on draglines connected with attachment discs on different hydrophilic substrates point to dragline rupture as the failure mode. The Young´s modulus of the dragline (8.3 GPa) is within the range as in terrestrial spiders. The shown structural and behavioral adaptations can be the model for new artificial underwater gluing devices.

Bond Strength of a Novel Universal Resin Cement to Dentin with or without an Adhesive Bonding Agent: An In Vitro Study.

The purpose of this study was to evaluate the bond strength and fracture mode of universal resin cement to dentin compared to self-adhesive and adhesive resin cement with and without an adhesive bonding agent. Seventy-two molar teeth were sectioned to expose coronal dentin, divided into three groups, and assigned to RelyX Universal (universal), RelyX Ultimate (adhesive), or RelyX Unicem 2 (self-adhesive) cements from 3M. The 3 groups were further subdivided into 2 subgroups of 12 specimens each, with or without the use of an adhesive bonding agent. Lithium-disilicate discs were bonded to the dentin surface using the cements, stored for 24 hours in distilled water, and subjected to 2,000 thermocycles before shear bond strength testing and fracture mode analysis. Significant differences in bond strength and fracture mode were found between groups based on cement or the use of a bonding agent. Both the universal and adhesive cements had significantly greater bond strengths to dentin with the use of a bonding agent versus no bonding agent. With the self-adhesive cement, there was no significant increase in bond strength to dentin with the use of a bonding agent. The novel universal resin cement had similar bond strengths to dentin as the adhesive cement with the use of a bonding agent, and similar bond strengths as the self-adhesive cement without the use of a bonding agent. The adhesively bonded universal cement had the greatest percentage of mixed and cohesive fractures. When greater adhesion is needed clinically, the novel universal resin cement may be used with an adhesive bonding agent. However, when less adhesion is needed, it could be used without a bonding agent in self-adhesive mode.

Adhesive bond strength of monolithic zirconia ceramic finished with various surface treatments.

This study aimed to investigate different surface treatments thought to increase the bond strength between zirconia ceramic and adhesive resin cement. The samples were prepared in 15 × 10 × 2mm dimensions by cutting off monolithic zirconia ceramic blocks (Incoris TZI; Sirona, Germany). Surface roughness measurements were made with a profilometer, the average surface roughness (Ra1) was recorded, and five different surface treatments were applied. Group 1: Control group. No surface treatment was applied. Group 2: Sandblasted with Al2O3 under pressure of 50μm. Group 3: Sandblasted with 30μm Al2O3 - SiOx under pressure, then tribochemical silica coating, silane bonding agent, and ceramic primer were applied. Group 4: Samples were etched in a hot acid solution containing methanol, HCl, and chloride at 100°C. Group 5: Samples were coated in a solution containing Grade C Aluminum Nitrite at 75°C for 15 Sects.12,000 thermal aging was carried out to all samples. Then, samples were bonded to a composite surface (Filtek Z250) with two different types of adhesive cement (Panavia F 2.0, Rely X U200) (n = 10). A load was applied to the samples attached to the Universal Test Device for the SBS, and the SBS was recorded. The surface roughness measurements of all samples were made again, and the average surface roughness Ra2 was recorded. The data was analyzed with a two-way ANOVA test. Bonferroni correction was used for multiple comparisons of the groups. p = 0.005 was accepted as the statistically significant value. There was no statistically significant difference between the groups in the Ra1 measurements (p = 0.031). There was a statistically significant difference between the Ra2 values of Groups 4 and 5 and the Ra2 values of Groups 1,2 and 3 in the Ra2 measurements (p < 0.001). There was no statistically significant difference between the SBS values of the groups (p > 0.005). Also, there was no statistically significant difference in the SBS values of all groups for the two different cements tested (p > 0.005). None of the surface treatments applied to monolithic zirconia ceramic samples increased the SBS between ceramic and adhesive resin cement.

Clinical Performance of Minimally Invasive Monolithic Ultratranslucent Zirconia Veneers: A Case Series up to Five Years of Follow-up

SUMMARY There is a lack of reports in the literature on the long-term clinical performance of ultratranslucent zirconia, especially considering its use in manufacturing monolithic veneers. The purpose of this case series is to describe the aesthetic treatment steps of three patients with minimally invasive ultratranslucent zirconia veneers and to report the clinical findings up to five years. Three patients (woman: 2, man: 1; mean age: 30 years) unsatisfied with their dental aesthetics sought dental treatment. The treatment plan involved cementing ultratranslucent zirconia veneers. Air-abrasion was performed on the internal surface of zirconia with alumina particles coated by silica (silicatization), followed by silane and adhesive applications for the adhesive cementation. All veneers were adhesively cemented to enamel with resin cement (Variolink Esthetic, Ivoclar). The patients were clinically evaluated annually considering the Ryge modified/ California Dental Association criteria. After a mean follow-up of 4.33 years (4-5 years), a survival rate of 100% was detected for the 28 minimally invasive ultratranslucent zirconia veneers cemented in the 3 patients. There were no absolute failures such as debonding, veneer fracture, or secondary caries. Superficial marginal discoloration was observed in one element (maxillary left lateral incisor) of one patient. Ultratranslucent zirconia is a viable option for manufacturing veneers due to its excellent clinical performance and longevity. However, further long-term clinical studies are essential to consolidate this material as an option for esthetic restorations.