Proanthocyanidin, a natural phytochemical bioactive agent, simultaneously can silence the activity of dentinal proteases and crosslink the collagen matrix; both of these phenomena would be the fundamentals for bio-stability of resin-dentin interface which is essential for a promising adhesive dentistry. This review provides an overview of the data developed by different groups of researchers and highlighted topics are proanthocyanidin chemistry, natural resources and the unique interactions between proanthocyanidincollagen and proanthocyanidin-MMPs in dentin. Besides, clinical applications of proanthocyanidin in the form of proanthocyanidin-containing adhesives, preconditioners and etchants have been reviewed. One hundred and twelve studies have been published in peer-reviewed journals from 1981 to 2017, all were comprised in this review, some of them have been actually proven to be promising from clinical point of view and others need further assessment before their adoption as clinically practicable protocols.

Quaternary ammonium compounds (QACs) have been used widely in medicine, owing to their antimicrobial properties. They also have strong permeability, stable performance, low skin irritation, low toxicity, low corrosion, lasting biological effects and so on, comparing with other antimicrobial agents. At the end of last century, polymerizable quaternary ammonium antimicrobial monomers had been synthesized and applied in dentistry, in order to reduce or prevent microbial biofilm formation on dental materials surfaces. This review aims to discuss the current progress of QACs applied in composite resin, adhesive systems, acrylic resin, glass ionomer cement and endodontic materials, regarding to their antimicrobial potential, mechanical properties, and biocompatibility.

The resin-coating technique is one of the successful bonding techniques used for the indirect restorations. The dentin surfaces exposed after cavity preparation are coated with a thin film of a coating material or a dentin bonding system combined with a flowable composite resin. Resin coating can minimize pulp irritation and improve the bond strength between a resin cement and tooth structures. The technique can also be applied to endodontically treated teeth, resulting in prevention of coronal leakage of the restorations. Application of a resin coating to root surface provides the additional benefit of preventing root caries in elderly patients. Therefore, the coating materials have the potential to reinforce sound tooth (“Super Tooth” formation), leading to preservation of maximum tooth structures.

Titanium surface modification is critical for dental implant success. Our aim was to determine surfaces influence on dental pulp stem cells (DPSCs) viability and differentiation. Implants were divided into sandblasted/acid-etched (control) and sandblasted/acid-etched coated with calcium and magnesium ions (CaMg), supplied as composite (test). Proliferation was evaluated by MTT, differentiation checking osteoblastic gene expression, PGE2 secretion and matrix formation, inflammation by Interleukin 6 (IL-6) detection. MTT and IL-6 do not modify on test. A PGE2 increase on test is recorded. BMP2 is higher on test at early experimental points, Osterix and RUNX2 augment later. Alizarin-red S reveals higher matrix production on test. These results suggest that test surface is more osteoinductive, representing a start point for in vivo studies aiming at the construction of more biocompatible dental implants, whose integration and clinical performance are improved and some undesired effects, such as implant stability loss and further surgical procedures, are reduced.

Determining the energy transferred at the bottom of eleven bulk-fill resin composites, comparing top and bottom microhardness’s and evaluating the correlation between microhardness and radiant energy were aimed. Samples were placed over the bottom sensor of a visible light transmission spectrophotometer and polymerized for 20 s. The bottom and top Knoop microhardness were measured. Paired t-test and correlation analysis were used for statistics (p≤0.05). In all groups, the bottom radiant energy decreased significantly with increasing thickness. For groups of Aura 2 mm, X-tra Fil 2 and 4 mm, SDR 2 and 4 mm, X-tra Base 2 mm no significant difference was found between top and bottom microhardness. For the bottom levels of Aura, X-tra Fil, Filtek Bulk-Fill Posterior, SDR, X-tra Base groups no significant difference was found between the microhardness’s of 2 and 4 mm thicknesses. For X-tra Fil, Tetric Evo Ceram Bulk-Fill, Filtek Bulk-Fill Flowable and Z100 groups radiant energy affected positively the microhardness.

The objectives were to analyze the oxide layer generated between titanium and porcelain during firing and compare it in different manufacturing techniques: cast, milled and EBM-technique. Seventy two specimens were manufactured, subdivided according to surface treatment: time of passivation (P) and no time of passivation (NP) before porcelain firing. Specimens from each group were analyzed with scanning electron microscopy: one only fired once, and one subjected to six firings. Remaining specimens were subjected to shear bond strength test. The EBM-produced NP-group had highest mean value (25.0 MPa) and the milled P-group showed lowest mean value (18.5 MPa) when all factors were compared. No significant difference was detected according to time of passivation. SEM showed consistent and well-defined boundary between the different layers. Time of passivation and impact on oxide growth was not detected. The bond strength of porcelain to milled titanium is lower when compared to cast titanium and EBM-produced titanium.

Zirconia implants that were restored with veneered zirconia displayed severe chipping rates of the restorations in clinical studies. Purpose of this study was to evaluate the fracture load of different zirconia implant supported monolithic crown materials (zirconia, alumina, lithium disilicate, feldspar ceramic and polymer-infiltrated ceramic) cemented with various cements (Harvard LuteCem SE, Harvard Implant Semi-permanent, Multilink Automix, VITA Adiva F-Cem). Flexural strength and fracture toughness of crown materials and compressive strength of the cements were measured. Fracture load values of crowns fabricated from lithium disilicate, feldspar ceramic and polymer-infiltrated ceramic were increased when cement with high compressive strength was used. Fracture loads for zirconia and alumina crowns were not influenced by the cement. Flexural strength and fracture toughness of the ceramics correlated linearly with the respective fracture load when using adhesive cement with high compressive strength. To achieve sufficient fracture load values, cementation with adhesive cement is essential for feldspar and polymer-infiltrated ceramic.

This study developed carbon nanotube coatings for the dentin surface and investigated the bonding strength and the in vitro antibacterial properties of carbon nanotube-coated dentin. Single-walled carbon nanotubes and multi-walled carbon nanotubes were first modified and then characterized using Fourier-transform infrared spectroscopy, scanning electron microscope, and transmission electron microscopy. Second, dentin samples were coated using either single-walled carbon nanotubes or multi-walled carbon nanotubes and observed under a scanning electron microscope. Then, the shear bonding strength and antibacterial properties of the dentin samples were tested. The results showed that both modified single-walled carbon nanotubes and multi-walled carbon nanotubes formed a stable coating on the dentin surface without affecting the shear bonding strength. Moreover, the antibacterial properties of the single-walled carbon nanotube-coated samples was obviously superior to those of the multi-walled carbon nanotube-coated samples. Consequently, single-walled carbon nanotube coating may be an antibacterial agent for potential application in the dental bonding field.

Zirconia exhibits good tissue compatibility and nontoxicity, making it a widely used esthetic replacement material for implant abutments. To avoid abutment-fracture, the parts composed of zirconia with a bonded metal component connected to the implant can be used. The purpose of this study was to design titanium and zirconia components with high fracture resistance at the zirconia component’s edge line. Three edge line designs of the titanium base and zirconia sleeve were made: chamfer, shoulder, and back-taper. To assess the strength of the abutment design, static loads were applied vertically and 30 degrees from the vertical axis. A test of tensile strength was also performed after chewing simulation. Conventional zirconia components mounted on a chamfer-type titanium base showed significantly lower fracture resistance than shoulder and back-taper types. This study suggests that to improve the durability of zirconia abutments with a titanium base, a back-tapered edge design is recommended.

The effect of phosphoric acid pre-etching on enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives was investigated. Four universal adhesives and three two-step self-etch adhesives were used. The initial shear bond strengths and shear fatigue strengths to enamel with and without phosphoric acid pre-etching using the adhesives were determined. SEM observations were also conducted. Phosphoric acid pre-etching of enamel was found to increase the bond fatigue durability of universal adhesives, but its effect on two-step self-etch adhesives was material-dependent. In addition, some universal adhesives with phosphoric acid pre-etching showed similar bond fatigue durability to the two-step self-etch adhesives, although the bond fatigue durability of universal adhesives in self-etch mode was lower than that of the two-step self-etch adhesives. Phosphoric acid pre-etching enhances enamel bond fatigue durability of universal adhesives, but the effect of phosphoric acid pre-etching on the bond fatigue durability of two-step self-etch adhesives was material-dependent.

The objectives of this study were to compare the fracture strength of endocrown restorations fabricated with different preparation depth and various CAD/CAM ceramics, and to assess the fracture types. Endodontically treated 100 extracted human permanent maxillary centrals were divided into two preparation depth groups as short (S: 3-mm-deep) and long (L: 6-mm-deep), then five ceramic subgroups, namely: feldspathic-ceramic (Vita Mark II-VM2), lithium-disilicate glass-ceramic (IPS e.max CAD-E.max), resin-ceramic (LAVA Ultimate-LU), polymer infiltrated ceramic (Vita Enamic-VE) and monoblock zirconia (inCoris TZI-TZI) (n=10/subgroup). The endocrowns were fabricated by CAD/CAM and were cemented with resin cement (RelyX U200). The teeth were thermally cycled (5,000cycles) and fracture tests were performed at 45º angle to the teeth. The data were statistically analyzed (Kruskal-Wallis, Mann Whitney U), failure modes were evaluated with stereomicroscopy. Zirconia group provided the statistically highest fracture strength, but also exhibited non-repairable failures. Preparation depth has an effect on the fracture strength only for feldspathic ceramic.

This study aimed to evaluate the shear bond strength (SBS) and microleakage of a new self-etch adhesive-based fissure sealant (EG) on aprismatic enamel in comparison to conventional fissure sealing with 30 s acid etching (CG). The fissures were sealed according to the manufacturer’s instructions. Each group was divided into 3 subgroups: 1-day water storage, 3-month water storage, and 5,000× thermocycling. After measuring SBS using the Ultradent method, failure mode was analyzed. In additional 16 teeth, microleakage was tested using dye penetration method. Pairwise comparisons were analyzed using Mann-Whitney U-Test. Multiple linear regression was performed to assess the factors influencing on SBS. EG had significantly lower mean SBS (4.1 MPa±2.1) than the CG (17.6 MPa±6.4). CG (1.1%) performed significantly better than the EG (12.8%) in microleakage analysis. The tested EG yielded significantly inferior results and its clinical use should be decided after weighing its pros and cons.

The surface topography of implant fixture is an important factor affecting the osseointegration. We herein demonstrated the effects of surface microtopography of titanium disks on proliferation and differentiation of osteoblast-like cells isolated from rat calvariae. Titanium disks with machine surface (MS), rough surface (R1) and rough surface combined with small cavities (R2) were used in an in vitro culture system. Rough surfaces (R1 and R2 disks) induced stronger osteoblast proliferation and differentiation (BGP and sclerostin mRNA expressions and calcium content) than the smooth surface (MS disk). Furthermore, surface microtopography of R2 disk, which was rough with small cavities, more strongly induced cell proliferation and mineralized bone matrix production than R1 disk. Our results suggest that surface microtopography influences osteoblast proliferation and differentiation. R2 disk, which is rough with small cavities, may be used in implant fixtures to increase osseointegration.

The aim of the study was to investigate cell adhesion to micro-structured titanium. Osteoblastic MC3T3 cells were cultured on smooth (P) or sand-blasted/acid-etched (SLA) titanium discs and were observed at scanning electron microscope/focused ion beam (SEM/FIB). Myosin II and actin microfilaments were labelled for epifluorescence microscopy. FIB revealed that cell adhesion initiated centrally and expanded to the cell periphery and that cells attached on the substrate by bridging over the titanium irregularities and adhering mostly on surface peaks. Gaps were visible between concave areas and cytoplasm and areas around ridges represented preferred attachment points for cells. A different myosin distribution was observed between samples and myosin inhibition affected cell responses. Taken together our data indicate that cells attach on micro-rough titanium by bridging over its irregularities. This is likely mediated by myosin II, whose distribution is altered in cells on SLA discs.

Titanium nitride (TiN) coating by ion plating has properties such as high hardness, wear resistance, corrosion resistance, and surface lubricity, therefore TiN coating is often used in various dental appliances and materials. In this study, we evaluated the corrosion behaviors and mechanical properties of TiN coated stainless steel (SS) and nickel titanium (Ni-Ti) orthodontic wires prepared by ion plating. TiN coating by ion plating improves the corrosion resistance of orthodontic wires. The corrosion pitting of the TiN coated wire surface become small. The tensile strength and stiffness of SS wire were increased after TiN coating. In contrast, its elastic force, which is a property for Ni-Ti wire, was decreased. In addition, TiN coating provided small friction forces. The low level of friction may increase tooth movement efficiently. Therefore, TiN coated SS wire could be useful for orthodontics treatment.

This study aimed to evaluate and compare certain mechanical properties, Vickers-hardness, water sorption, fluoride-release, shrinkage-stress and wear of five commercial fluoride-releasing restorative materials (Dyract, CompGlass, BEAUTIFIL II, ACTIVA-Restorative, and GC Fuji II LC), in relation to their microstructural characteristics. Mechanical properties were determined for each material following ISO standards. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Daily fluoride-release was measured during the first 10 days by using a fluoride ion selective electrode. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Results were statistically analysed using ANOVA followed by post hoc Tukey’s test. ACTIVA-Restorative exhibited the highest fracture toughness (1.1 MPa m^1/2) among the materials tested. BEAUTIFIL II presented the highest flexural strength (145 MPa) which was not significantly different (p>0.05) from CompGlass and Dyract. Highest fluoride-release measurement was located for GC Fuji II LC among other tested materials.

The aim of this study was to investigate the effect of three metal priming agents on the bond strength of adhesive resin cement to Silver-Zinc-Tin-Indium (Ag-Zn-Sn-In) alloy and pure Ag, Zn, Sn, and In. The specimens were air-abraded with alumina and then primed with one of three metal priming agents: V-Primer, Estenia Opaque Primer, or Alloy Primer. The metal disks were bonded with adhesive resin cement (Super-Bond Bulk-mix technique). Shear bond strengths (n=10/group) were determined before and after 50,000 thermocycles for Ag-Zn-Sn-In alloy as well as after 5,000 thermocycles for pure Ag, Zn, Sn and In. For Ag-Zn-Sn-In alloy, the post-thermocycling bond strength of the Alloy Primer group was significantly higher than that of the other primers. It can be concluded that Alloy Primer containing both the vinyl-thione monomer (VBATDT) and hydrophobic phosphate monomer (MDP) is effective for bonding Ag-Zn-Sn-In alloy and pure Ag, Zn and Sn.

The objective was to investigate the influence of grade and surface topography of commercially pure titanium (Cp-Ti) on fatigue properties evaluated via staircase method. Cp-Ti grades 2 and 4 were roughened by shot blasting and acid etching, and compared with machined specimens. Yield force under static loading for Cp-Ti grades 2 and 4 were 672±51 and 1,088±93 N for machined and 724±99 and 1,118±96 N for roughened group. Yield force under cyclic loading for Cp-Ti grades 2 and 4 decreased 27 and 40% compared to static loading. Cp-Ti grade 4 demonstrated significantly greater decrease in yield force after cyclic loading; however surface topography had no effect.

The present study was to evaluate fiber mesh loaded with naringin via electrospinning to guide bone regeneration in vitro. The naringin-loaded fiber mesh was prepared via elctrospinning of PLGA, PLLA, PDLLA blending solution with naringin. SEM showed that naringin decreased the fiber’s diameter according to the concentration of naringin. After 20 days’ degradation in PBS, the drug-loaded fiber meshes still kept their stability with about 10% decrease in tensile strength. In vitro release experiments showed a sustained and steady naringin releasing profile with little initial burst releasing. Compared to the mats without naringin, the fiber mats loaded with naringin showed the most pronounced enhancement of cell growth when MC3T3-E1 cells were cultured on the fiber mats. The blend fiber loaded with naringin has optimized physical properties and sustained release profile in vitro. The study presents a promising fibrous mesh material for guided bone regeneration therapy.

This study was to ascertain if grape seed extract (GSE) can restore the shear bond strength (SBS) of total-etching adhesive to enamel immediately after bleaching. Immediately after bleaching with Beyond gel, different concentrations of GSE were applied to the surface of bovine enamel for 1 min before bonding of resin composite with Adper single bond 2 or All-Bond 3 adhesive. SBS values and debonding modes were recorded. Structure of the bonding interface and elements on enamel surface were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). SBS was found to be compromised significantly in 0 and 2.5% GSE groups. GSE (≥5%) could restore the SBS to the level of control. Failure in the adhesive joint was always the major debonding mode. No significant difference was found by XPS. Thus, GSE can restore the SBS compromised after bleaching in 1 min if the concentration is ≥5%.

The aim of the present study was to evaluate the physiochemical properties and resorption progress of two cross-linked, porcine skin-derived collagen membranes and compare their features with those of a membrane without cross-linking (Bio-Gide^® [BG], Geistlich Biomaterials, Wolhusen, Switzerland). Three porcine skin-derived collagen membranes, dehydrothermally (DHT) cross-linked (experimental), DHT and 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide (DHT/EDC) cross-linked (experimental) and BG were investigated for their morphology, enzyme resistance, and tensile strength in vitro and biodegradation in vivo. DHT and DHT/EDC membranes exhibited irregular, interconnected macro- and micropores that formed a 3D mesh, whereas BG exhibited individual collagen fibrils interlaced to form coarse collagen strands. In enzyme resistance and tensile strength tests, DHT and DHT/EDC membranes demonstrated good resistance and mechanical properties compared with BG. In vivo, all three membranes were well integrated into the surrounding connective tissue. Thus, the DHT membrane exhibited its potential as a barrier membrane for guided bone and tissue regeneration.

This study aimed to investigate the influence of enamel prism orientations on color adjustment of resin composite restoration. The color measurements (L*, C*, or h* values) at the restored bovine enamel disk (1.0 mm-thick) with resin composite (Estelite Asteria, Estelite Pro, Kalore, Clearfil Majesty) were performed using a CIE XYZ camera (RC500). The color shifting rate and range at the coronal and cervical border were calculated. The coronal border was significantly lower L* and C* color shifting rate than the cervical border (p<0.05). The L* color shifting range was significantly affected by regions in the 3-mm cavity group (p<0.05), but not in the 1-mm cavity group (p>0.05), while the C* color shifting range was not significantly affected by regions (p>0.05). The coronal enamel border with diagonal-cut of enamel prisms would have an advantage for color adjustment of resin composite restorations compared to the cervical border with longitudinal-cut of enamel prisms.

This study evaluated low-viscosity resin potential as enamel marginal gap sealant for existing composite restoration. Standard restorations with marginal gaps were created in bovine teeth; gaps were resealed using G-Bond Plus (GB, GC, Tokyo, Japan) or Icon (ICN, DMG, Hamburg, Germany) with or without HCl pretreatment (n=8). Swept-source optical coherence tomography (SS-OCT) images were taken before and after resealing of the margin and thermal cycling to calculate enamel marginal gap extent. Cross-sectional microscopy was performed to confirm SS-OCT findings. SS-OCT showed remarkable reduction of backscatter signal at enamel margins after application of the low-viscosity resin. Enamel margin resealing significantly decreased gap and there was a significant difference between ICN (regardless of HCl pretreatment) and GB, while thermal cycling increased gaps (p<0.05). The low-viscosity resin could effectively infiltrate micro-gaps at enamel margins and improve sealing of an existing composite restoration. Resin infiltration is a viable option for resealing intact restorations with open margins.