Theranostic doxorubicin encapsulated FeAu alloy@metal-organic framework nanostructures enable magnetic hyperthermia and medical imaging in oral carcinoma.

Metal-organic frameworks (MOFs) have emerged as attractive candidates in cancer theranostics due to their ability to envelop magnetic nanoparticles, resulting in reduced cytotoxicity and high porosity, enabling chemodrug encapsulation. Here, FeAu alloy nanoparticles (FeAu NPs) are synthesized and coated with MIL-100(Fe) MOFs to fabricate FeAu@MOF nanostructures. We encapsulated Doxorubicin within the nanostructures and evaluated the suitability of this platform for medical imaging and cancer theranostics. FeAu@MOF nanostructures (FeAu@MIL-100(Fe)) exhibited superparamagnetism, magnetic hyperthermia behavior and displayed DOX encapsulation and release efficiency of 69.95 % and 97.19 %, respectively, when stimulated with alternating magnetic field (AMF). In-vitro experiments showed that AMF-induced hyperthermia resulted in 90 % HSC-3 oral squamous carcinoma cell death, indicating application in cancer theranostics. Finally, in an in-vivo mouse model, FeAu@MOF nanostructures improved image contrast, reduced tumor volume by 30-fold and tumor weight by 10-fold, which translated to enhancement in cumulative survival, highlighting the prospect of this platform for oral cancer treatment.

EFFECT OF FRAMEWORK MATERIAL ON THE CLINICAL OUTCOMES OF FULL ARCH IMPLANT SUPPORTED PROSTHESES REMAINS UNQUANTIFIABLE.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Delucchi, F.; De Giovanni, E.; Pesce, P.; Bagnasco, F.; Pera, F.; Baldi, D.; Menini, M. Framework Materials for Full-Arch Implant-Supported Rehabilitations: A Systematic Review of Clinical Studies. Materials 2021, 14, 3251. https:// doi.org/10.3390/ma14123251 SOURCE OF FUNDING: This research received no funding. TYPE OF STUDY/DESIGN: Systematic Review (SR).

Restoration of 1325 teeth with partial-coverage crowns manufactured from high noble metal alloys: a retrospective case series 18.8 years after prosthetic delivery.

OBJECTIVES: To evaluate long-term survival and success rates of conventionally cemented partial-coverage crowns (PCCs) manufactured from high noble metal alloys (hn). MATERIAL AND METHODS: Restoration-, periodontal- and tooth-related criteria on patients, restored with a single or multiple conventionally cemented hnPCCs in a private dental office were collected from existing patient records. With regard to semi-annual follow-ups, data of the most recent clinical evaluations were considered. Kaplan-Meier and log-rank tests were used for statistical analyses. Level of significance was set at p ≤ .05. RESULTS: Between 09/1983 and 09/2009, 1325 hnPCCs were conventionally cemented on 1325 teeth in 266 patients (mean age: 44.5 ± 10.7 years). Due to various reasons, 81 hnPCCs showed complications, documenting a success rate of 93.9% after a mean observation period of 18.8 ± 5.7 years. Of these, additional 14 restorations were counted as survival, resulting in a survival rate of 94.9%. Most frequent complications were periodontal issues (n = 29, 35.8%). Significantly higher success rates were documented for hnPCCs of patients aged between 37 and 51 years (p = .012). CONCLUSION: Partial-coverage crowns from high noble metal alloys showed excellent survival and success rates after a mean observation period of 18.8 ± 5.7 years. Higher patient age was one of the risk factors. CLINICAL RELEVANCE: According to the results of this study, hnPCCs still represent an excellent therapeutic option-even in modern dentistry.

Fracture Strength of Endodontically treated Maxillary Central Incisors restored with Nickel Chromium and Nonprecious Gold Alloy Casting Post and Cores.

AIM: Since fiber posts are not recommended for teeth under lateral loads, a new alloy containing >80% copper (nonprecious gold or NPG) was introduced with a modulus of elasticity closer to that of dentin and easier preparation. This study aimed to compare the fracture strength of endodontically treated maxillary central incisors restored with nickel chromium (Ni-Cr) and NPG alloys. MATERIALS AND METHODS: Casting post and cores were fabricated of Ni-Cr and NPG alloys for 24 maxillary central incisors (n = 12). Full-metal crowns were also fabricated and placed under cyclin loading in 30 N load and 45° angle, for 250,000 cycles with 2.6 Hz frequency. The fracture strength was measured at a crosshead speed of 0.5 mm/min and 135° angle in a universal testing machine. Data were analyzed using independent t-test. RESULTS: The mean fracture strength was 731.179 ± 327.47 and 1411.89 ± 313.56 N in the Ni-Cr and NPG groups respectively; this difference was statistically significant (p < 0.001). The fracture was irreparable in all teeth since the fracture line was below the cementoenamel junction (CEJ). CONCLUSION: The fracture strength of teeth restored with cast NPG post and cores was significantly higher than that of teeth restored with cast Ni-Cr post and cores. CLINICAL SIGNIFICANCE: Due to proper mechanical properties, NPG post and cores seem to be a suitable choice for restoration of severely damaged anterior teeth, provided that other properties are proven to be acceptable.

Three-dimensional finite element analysis of zirconia all-ceramic cantilevered fixed partial dentures with different framework designs.

The purpose of this study were: to perform stress analyses using three-dimensional finite element analysis methods; to analyze the mechanical stress of different framework designs; and to investigate framework designs that will provide for the long-term stability of both cantilevered fixed partial dentures (FPDs) and abutment teeth. An analysis model was prepared for three units of cantilevered FPDs that assume a missing mandibular first molar. Four types of framework design (Design 1, basic type; Design 2, framework width expanded buccolingually by 2 mm; Design 3, framework height expanded by 0.5 mm to the occlusal surface side from the end abutment to the connector area; and Design 4, a combination of Designs 2 and 3) were created. Two types of framework material (yttrium-oxide partially stabilized zirconia and a high precious noble metal gold alloy) and two types of abutment material (dentin and brass) were used. In the framework designs, Design 1 exhibited the highest maximum principal stress value for both zirconia and gold alloy. In the abutment tooth, Design 3 exhibited the highest maximum principal stress value for all abutment teeth. In the present study, Design 4 (the design with expanded framework height and framework width) could contribute to preventing the concentration of stress and protecting abutment teeth.

Effect of Cold Deformation and Heat Treatment on the Microstructures and Mechanical Properties of Au-15Ag-12Cu-6Ni Alloy Sheets.

The evolution of the microstructure and hardness changes in the Au-15Ag-12Cu-6Ni alloy during the processes of cold rolling and annealing were investigated and the heat treatment regimen for the alloy was optimized in this article. The hardness of the alloy continuously increases with the cold rolling reductions, leading to continuous deformation of the grains during the cold rolling process, ultimately resulting in smaller grain sizes. Subsequent annealing induces recovery and recrystallization, achieving complete recrystallization at 700 °C. An intriguing softening effect is observed after annealing at 700 °C, manifesting in a significant reduction in hardness to 238 (Hv0.5). The cold deformation texture of the alloy aligns with the recrystallization texture type, exhibiting only a certain degree of angular deviation. This is primarily characterized by <111>//RD texture and a texture deviating 60° from RD towards TD. The performance of the finished sheet improves with the precipitation of ordered phases AuCu after a 300 °C heat treatment for 0.5 h, resulting in a remarkable hardness of 380 (Hv0.5).

Gold-Nanolayer-Derived Zincophilicity Suppressing Metallic Zinc Dendrites and Its Efficacy in Improving Electrochemical Stability of Aqueous Zinc-Ion Batteries.

Herein, an Au-coating layer adjusted on the surface of a Zn metal electrode that effectively suppresses the dendrite growth as well as the mechanisms underlying the dendrite suppression as a result of the zincophilic character of Au is introduced. For the Au-coated Zn metal symmetric cell, uniform deposition of Zn-derived compounds was revealed by operando synchrotron tomography. Microscopic studies demonstrate that the Au-coating layer is induced to form a new Zn-Au alloy during the initial Zn deposition, resulting in stabilized long-term stripping/plating of Zn via the 'embracing effect' that intimately accommodates Zn deposition for further cycles. This property supports the successful operation of symmetrical cells up to 50 mA cm-2 . According to Zn electrodeposition simulation, it is verified that the suppression of dendrite growth is responsible for the electro-conducting Au nanolayer that uniformly distributes the electric field and protects the Zn electrode from corrosion, ultimately promoting uniform Zn growth. The compatibility of the Au-coating layer for full cell configuration is verified using NaV3 O8 as a cathode material over 1 000 cycles. This finding provides a new pathway for the enhancement of the electrochemical performance of ZIBs by suppressing the dendritic growth of Zn by means of a zincophilic Au nanolayer.

Effect of multi-purpose primer on bonding of acrylic resin to cast titanium and gold alloy after airborne-particle abrasion.

PURPOSE: To clarify the effect of a multi-purpose primer combining several functional monomers on two prosthodontic materials (cast titanium and a gold alloy) after airborne-particle abrasion. METHODS: Disk-shaped adherends were prepared from cast titanium (CP Titanium JIS2) and a gold alloy (Casting Gold M.C. Type IV). A silane-containing two-liquid primer (M&C primer (MC)) and two silane-free single-liquid primers (Alloy Primer (AP) and V-Primer (VP)) were used as surface-treatment agents. The shear bond strengths were determined before and after thermocycling to evaluate the adhesive durability, and the results were compared using a non-parametric statistical analysis. The effect of airborne-particle abrasion with alumina on the titanium surface was analyzed by X-ray photoelectron spectroscopy (XPS). RESULTS: There was no significant difference in bond strength between the MC and AP before and after thermocycling, whereas VP showed significantly lower values. XPS revealed that the titanium acquired hydrophilic properties after the airborne-particle abrasion. CONCLUSIONS: The novelty of this study is that it shows that the presence/absence of the silane had no effect on the bonding of cast titanium with an acrylic resin. The study also showed that the multi-purpose primer can be used without any problems with both cast titanium and gold alloy, in combination with airborne-particle abrasion with alumina.

Host Responses in Peri-implant Tissue in Comparison to Periodontal Tissue: A Retrospective Study.

PURPOSE: To investigate inflammatory responses in peri-implant crevicular fluid (PICF) in comparison to periodontal tissue. MATERIALS AND METHODS: Nineteen participants with healthy implants restored with titanium or gold-casting abutment were included. PICF and gingival crevicular fluid (GCF) were collected for inflammatory cytokine detection by ELISA. Cytokine levels in PICF or GCF of the same individual were compared using the paired t-test, and those from titanium or gold-casting (UCLA) abutment were compared using the independent t-test. Human gingival fibroblast responses to PICF and GCF were then evaluated with one-way ANOVA. RESULTS: The results demonstrated that IL-6, IL-8, TNFα, and IFNγ expressed in PICF are similar to GCF in the same individual. However, IL-1ß (p = 0.032) and IL-1α (p = 0.030) was statistically significantly higher in PICF than in GCF. IL-8 level was statistically significantly higher with gold-casting than with titanium abutments (p = 0.003). PICF statistically significantly stimulated higher expression of RANKL, IL-1ß, IL-6, and IL-8 mRNA in human gingival fibroblasts (HGF), while focal adhesion kinase (FAK) suppressed mRNA. CONCLUSION: The inflammatory cytokines, including IL-1α and IL-1ß, are higher in healthy peri-implant tissues. Abutment materials may also influence the level of inflammatory cytokines in PICF. Inflammatory mediators in crevicular fluid may affect HGF inflammatory responses and peri-implant tissue integration.

Wear Properties of Conventional and High-Translucent Zirconia-Based Materials.

This study investigated the two-body wear resistance of a first generation 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP), a second generation 3Y-TZP, a third generation 4 mol% yttria partially stabilized zirconia (4Y-PSZ), a 5 mol% yttria partially stabilized zirconia (5Y-PSZ), and a type III gold alloy (Aurocast 8), performed using opposing antagonistic cusps made out of the same material. Eight cylindrical specimens were prepared for each material (n = 8) for a total of forty specimens (N = 40). Conical cusps were fabricated for each material. Each cylinder−cusp pair was arranged inside a two-axis chewing simulator over up to 360,000 loading cycles. The wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm3). The antagonist wear (mm) was recorded before and after the wear test to evaluate the linear difference. Statistical analysis was performed using one-way analysis of variance (ANOVA); multiple comparisons were performed according to Tukey's method. No statistically significant differences (p > 0.05) among the first generation 3Y-TZP, second generation 3Y-TZP, and 4Y-PSZ wear were found. 5Y-PSZ showed statistically significant higher wear compared to other the zirconias. Aurocast 8 displayed the highest values in terms of vertical wear, antagonist cusp wear, and volumetric loss. Although still not statistically comparable, the wear behavior of the latest 5Y-PSZ was the closest to the widely recognized gold standard represented by the type III gold alloy.

Comparison of retentive forces between telescopic crowns made of poly(ether ether ketone) and type 4 gold alloy.

In this study, retentive forces were compared between telescopic crowns (TSC) made with poly(ether ether ketone) (PEEK) using computer-aided design and manufacturing and type 4 gold alloy using the conventional method. The retentive forces of TSCs were evaluated by performing a pull-out test with primary and secondary crowns. Initial retentive force was approximately 12 N for both PEEK and gold alloy TSCs. The retentive force of PEEK TSC was approximately 6.5 N after 10,000 cycles of insertion and removal. The reduction rate in retentive force was smaller for gold alloy TSC. PEEK TSC displayed greater surface roughness on the primary crown compared to the gold alloy TSC. Surface roughness slightly increased at the cervical margin after repetitive insertion and removal. The retentive force of PEEK TSC was smaller than gold alloy TSC, however the retentive force of PEEK TSC was adequate for stabilizing dental prostheses even after 10,000 cycles.

Evaluation of the effects of three pretreatment conditioners and a surface preparation system on the bonding durability of composite resin adhesive to a gold alloy.

This study aimed to evaluate the effect of three pretreatment conditioners and surface preparations on a composite resin adhesive for a gold alloy. Cast disk specimens were made and bonded with RelyX Unicem luting agent under six surface conditions: 1) polished with No.600 carbide paper, 2) air-abraded with alumina, 3) Alloy Primer metal conditioner was applied after alumina-abrasion, 4) Monobond Plus multipurpose conditioner was applied after alumina-abrasion, 5) M. L. Primer metal conditioner was applied after alumina-abrasion, and 6) Rocatec multipurpose silica-coating system was applied. The bond strengths were determined before and after thermocycling (50,000 cycles). The bond strengths of the alumina-abrasion group were significantly decreased after thermocycling. The Rocatec and M. L. Primer exhibited higher bond strengths than other treatments. The application of metal conditioners and multipurpose surface preparations was recommended for improved bonding between the evaluated adhesive resin and gold alloy.

The Technology Transfer from Europe to China in the 17th-18th Centuries: Non-Invasive On-Site XRF and Raman Analyses of Chinese Qing Dynasty Enameled Masterpieces Made Using European Ingredients/Recipes.

Two masterpieces of the Qing Dynasty (1644-1912 CE), one in gilded brass (incense burner) decorated with cloisonné enamels stylistically attributed to the end of the Kangxi Emperor's reign, the other in gold (ewer offered by Napoleon III to the Empress as a birthday present), decorated with both cloisonné and painted enamels bearing the mark of the Qianlong Emperor, were non-invasively studied by optical microscopy, Raman microspectroscopy and X-ray microfluorescence spectroscopy (point measurements and mapping) implemented on-site with mobile instruments. The elemental compositions of the metal substrates and enamels are compared. XRF point measurements and mappings support the identification of the coloring phases and elements obtained by Raman microspectroscopy. Attention was paid to the white (opacifier), blue, yellow, green, and red areas. The demonstration of arsenic-based phases (e.g., lead arsenate apatite) in the blue areas of the ewer, free of manganese, proves the use of cobalt imported from Europe. The high level of potassium confirms the use of smalt as the cobalt source. On the other hand, the significant manganese level indicates the use of Asian cobalt ores for the enamels of the incense burner. The very limited use of the lead pyrochlore pigment (European Naples yellow recipes) in the yellow and soft green cloisonné enamels of the Kangxi incense burner, as well as the use of traditional Chinese recipes for other colors (white, turquoise, dark green, red), reinforces the pioneering character of this object in technical terms at the 17th-18th century turn. The low level of lead in the cloisonné enamels of the incense burner may also be related to the use of European recipes. On the contrary, the Qianlong ewer displays all the enameling techniques imported from Europe to obtain a painted decoration of exceptional quality with the use of complex lead pyrochlore pigments, with or without addition of zinc, as well as cassiterite opacifier.

Soft Tissue Interface with Various Kinds of Implant Abutment Materials.

Various materials, such as titanium, zirconia and platinum-gold (Pt-Au) alloy, have been utilized for dental implant trans-mucosal parts. However, biological understanding of soft tissue reaction toward these materials is limited. The aim of this study was to compare the response of cell lines and soft tissue to titanium, zirconia and Pt-Au substrata. The surface hydroxyl groups and protein adsorption capacities of the substrata were measured. Next, gingival epithelial-like cells (Sa3) and fibroblastic cells (NIH3T3) were cultured on the materials, and initial cell attachment was measured. Immuno-fluorescent staining of cell adhesion molecules and cytoskeletal proteins was also performed. In the rat model, experimental implants constructed from various materials were inserted into the maxillary tooth extraction socket and the soft tissue was examined histologically and immunohistochemically. No significant differences among the materials were observed regarding the amount of surface hydroxyl groups and protein adsorption capacity. Significantly fewer cells of Sa3 and NIH3T3 adhered to the Pt-Au alloy compared to the other materials. The expression of cell adhesion molecules and a well-developed cytoskeleton was observed, both Sa3 and NIH3T3 on each material. In an animal model, soft tissue with supracrestal tissue attachment was observed around each material. Laminin-5 immuno-reactivity was seen in epithelia on both titanium and zirconia, but only in the bottom of epithelia on Pt-Au alloy. In conclusion, both titanium and zirconia, but not Pt-Au alloy, displayed excellent cell adhesion properties.

Fracture Resistance of Titanium, Chrome-Cobalt, and Gold Alloy as Post and Core Materials: A Comparative Evaluation.

AIM: This study aimed to comparatively evaluate the fracture resistance of different metallic post and core materials. MATERIALS AND METHODS: Twenty-four maxillary-central incisors were selected, standardized, and segregated into three groups (GP I-III) (n = 8) based on the type of alloy used for post and core preparation. GP I (gold alloy [Au]), GP II (chrome-cobalt alloy [Co-Cr]), and GP III (titanium alloy [Ti]) were comparatively evaluated for use as post and core materials. The teeth were endodontically treated and tooth preparation for post core was done.Metal post and cores were fabricated using indirect wax pattern and luted. Teeth were mounted on resin bases, fracture testing was done, and type of fractures were analyzed. RESULTS: Mesiodistal type of fracture was the most common among experimental groups with a percentage incidence of 54.20%. The comminuted type of fracture was the next most common with a percentage incidence of 29.2%. The incidence of buccolingual, transverse, and other type of fracture was not common and had a percentage incidence of 29.2%, 4.2%, 8.3% and 4.2% respectively. Group II had the highest fracture resistance with a mean value of 742.89N. Group III and Group I had mean values of 482.33 and 361.1123N. Statistically significant difference between experimental groups (I and II) and (II and III) was observed in load values of root fracture (P < 0.05). CONCLUSION: On the basis of the protocols used and limitations of this study, among metallic post and core materials tested, GP II had the highest fracture resistance values. Further evaluation of these different post and core systems, new alloy formulations designed specifically for use as post and core materials, and assessment in a clinical setting is recommended.

Silver-gold alloy nanoparticles biofabricated by fungal xylanases exhibited potent biomedical and catalytic activities.

The search for biocompatible nanoparticles with vast applicability has impacted on exploration of various biomaterials for the synthesis of mono and bimetallic nanoparticles. Xylanase is widely regarded as an industrially important enzyme but its potentials in nanotechnological applications are yet to be fully explored. The current study investigates the exploit of xylanases of Aspergillus niger L3 (NE) and Trichoderma longibrachiatum L2 (TE) produced through valorization of corn-cob, to synthesize silver-gold alloy nanoparticles (Ag-AuNPs). Characterization of the Ag-AuNPs involved UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy and transmission electron microscopy, while their prospective use as antimicrobial, antioxidant, catalytic, anticoagulant, and thrombolytic agents were studied. The biosynthesized Ag-AuNPs were ruby red and light purple with surface plasmon resonance at 520 and 534 nm for NEAg-AuNPs and TEAg-AuNPs, respectively; while FTIR showed that protein molecules capped and stabilized the nanoparticles. The Ag-AuNPs were anisotropic with spherical, oval, and irregular shapes having sizes ranging from 6.98 to 52.51 nm. The nanoparticles appreciably inhibited the growth of tested clinical bacteria (23.40-90.70%) and fungi (70.10-89.05%), and also scavenged 2,2-diphenyl-1-picrylhydrazyl (48.51-53.79%) and hydrogen peroxide (80.5-95.50%). Furthermore, the Ag-AuNPs degraded malachite green (91.39%) and methylene blue (47.10%). Moreover, the Ag-AuNPs displayed outstanding anticoagulant and thrombolytic activities using human blood. This study further emphasizes the significance of xylanases in nanobiotechnology as it has established the potential of xylanases to synthesize Ag-AuNPs, which is being reported for the first time.

Effect of multi-purpose primers on the bond durability between tri-n-butylborane initiated resin and gold alloy.

PURPOSE: This study investigated the influence of an interaction between sulfur-containing monomers and other monomers in multipurpose primers on the bond durability of a tri-n-butylborane (TBB)-initiated acrylic resin to a gold alloy. METHODS: The disk-shaped adherend materials were prepared from a gold alloy (Casting Gold M.C. Type IV). Two multipurpose-primers (Universal Primer, Monobond Plus), four metal primers containing an organic sulfur compound (M.L. Primer, Alloy Primer, Metaltite, and V-Primer), and three acidic primers (Estenia Opaque Primer, Acryl Bond, and Super-Bond Liquid) were used. The shear bond strengths were determined pre- and post-thermocycling to evaluate the bond durability. A statistical analysis of the results was performed using a non-parametric procedure, and the cohesive failure ratios of the debonded surfaces were compared. RESULTS: Among the pre-thermocycling groups, M.L. Primer, Metaltite, Monobond Plus, Universal Primer, and Alloy Primer showed the greatest bond strengths. Among the post-thermocycling groups, M.L. Primer, Metaltite, Monobond Plus, and Universal Primer showed the greatest bond strengths, whereas Acryl Bond, Super-Bond Liquid, Estenia Opaque Primer, and the unprimed control showed the lowest. Similarly, the primers that did not contain either a sulfur compound showed an obvious reduction in the cohesive failure ratio. CONCLUSIONS: Multi-purpose primers containing a sulfur-containing monomer increased the bond strength of a TBB-initiated acrylic resin to a gold alloy. The proportion of the area of cohesive failure to the bonded area showed an interrelationship with the shear bond strength testing results.

Effect of silane coupling treatment and airborne-particle abrasion on shear bond strength between photo-cured bulk-fill flowable composite resin and silverpalladium-copper-gold alloy using self-adhesive resin cement.

The purpose of the present study was to examine the effects of silane coupling treatment and airborne-particle abrasion (APA) on shear bond strength (SBS) between photo-cured bulk-fill flowable composite resin and 12% silver-palladium-copper-gold (Ag-Pd-CuAu) alloy using self-adhesive resin cement. The six experimental groups were compared using two-way analysis of variance (ANOVA) followed by Tukey Kramer's post-hoc test to compare SBS values among the six groups at a 95% confidence level. The SBS of APA groups was significantly higher than non-APA groups. The SBS of the specimens with silane coupling treatment increased slightly compared with specimens without silane coupling treatment. The combination of resin coating with bulk-fill resin and self-adhesive resin cement could be clinically useful when restoring a cavity with a noble metal.

Histological evaluations and inflammatory responses of different dental implant abutment materials: A human histology pilot study.

BACKGROUND: Improvements of soft tissue to the abutment surface results in more stable peri-implant conditions, however, few human histological studies have compared soft tissue responses around different abutment materials. PURPOSE: To describe the peri-implant tissue around 3 abutment materials; titanium, zirconia, and gold alloy, over an 8-week healing period. MATERIALS AND METHODS: Fifteen edentulous sites were treated with implants. Eight weeks later, peri-implant tissue was harvested and processed using a nonseparation resin embedded technique. The tissue attachment characteristics were assessed at clinical stages using the gingival index (GI) score, surgical stage (surgical score), and histological stage (histological attachment percentage). Additionally, the inflammatory responses were evaluated using inflammatory extent and inflammatory cellularity grades. Nonparametrical statistics were used to describe the GI and surgical scores, and analytical statistics were used to analyze the histological attachment percentages as well as the inflammatory extent and cellularity grades amongst the 3 groups. RESULTS: There were no statistically significant differences among the groups for GI score (P = .071) and surgical score (P = .262). Titanium and zirconia exhibited nearly similar mean histological attachment percentages while gold alloy had a significantly lower percentage (P = .004). For the inflammatory extent and cellularity grades, the odds of being one grade higher for gold alloy abutment was 5.18 and 17.8 times that of titanium abutment, respectively. However, for the zirconia abutment, the odds were 0.87 and 7.5 times higher than the titanium group. CONCLUSIONS: The tissue around the gold alloy abutments resulted in worse attachment conditions compared with the titanium and zirconia abutments. Inflammation tended to be higher in the tissue around the gold alloy abutments than the titanium and zirconia abutments.

Trace of organic sulfur compounds detected from debonded interface between transparent acrylic resin and gold alloy.

The purpose of the current study was to evaluate the bonding performance of two single-liquid primers, which contained 6-(4-vinylbenzyl-n-propyl) amino-1,3,5-triazine-2,4-dithione (VTD) or 6-methacryloyloxyhexyl 2-thiouracil 5-carboxylate (MTU-6), used for bonding between metals and an acrylic resin. A gold alloy and high-purity titanium were used as adherend materials, and a transparent acrylic resin initiated with tri-n-butylborane derivative was selected as the luting material. Both adherends were treated with one of the primers and bonded with the luting material, after which shear bond strength was determined. Fourier transform infrared spectroscopy was used to analyze debonded resin specimens. Shear bond strength to gold alloy was significantly greater than that to titanium for both the VTD and MTU-6 primers. A trace of thiol structure, probably derived from VTD and MTU-6, was detected on resin surfaces debonded from gold alloy. These results indicate that the two organic sulfur compounds, which are stable in an atmospheric environment, are tautomerized into a thiol structure, thus allowing adsorption onto noble metals. In addition, the adsorbed thiol compounds contribute to chemical bonding between the acrylic resin and noble metal alloy, as polymerizable adhesive functional monomers.