Sandblasting increases the microtensile bond strength between resin and sclerotic dentin in noncarious cervical lesions.

PURPOSE: To evaluate the effect of sandblasting on the microtensile strength between sclerotic dentin and resin composite. METHODS: 32 premolars with noncarious cervical lesions (NCCLs) were collected, and the teeth were randomly assigned to the control group (C group) and the sandblasted group (S group). Teeth in the S group were sandblasted with 110 µm Al2O3 particles at a pressure of 75 psi, while those in the C group received no further treatment. The characteristics of the tooth surface were observed by scanning electron microscopy (SEM), and the relative area of open dentin tubules (OTs) was calculated by IPP6.0 software. Surface roughness (Ra) was also assessed. The noncarious cervical lesions of all teeth were restored with a resin composite and subsequently sectioned into sticks to measure the microtensile bond strength (µTBS). RESULTS: The mean ± SD µTBS (in MPa) of the sandblasted group was 17.9 ± 0.69 and 14.23 ± 0.44 in the control group (P< 0.05). The relative area of OTs at the gingival wall of the sandblasted group was 69.74 ± 5.23%, and 47.24 ± 7.67% in the control group (P< 0.05). The average surface roughness (µm) was 1.01 ± 0.05 in the sandblasted group and 0.16 ± 0.03 in the control group. Sandblasting could increase the bond strength of sclerotic dentin and resin restorations. CLINICAL SIGNIFICANCE: After sandblasting, the microtensile strength of sclerotic dentin on the surface of noncarious cervical lesions increased, prolonging the resin adhesion longevity. Sandblasting could also alleviate the pain of patients during the treatment process and achieve a minimally invasive treatment.

Effect of phosphoric acid containing polyvinylpyrrolidone as protective etchant for dentin bonding.

STATEMENT OF PROBLEM: Phosphoric acid is commonly used in dentistry as an etchant but can result in excessive demineralization of dentin, a major contributor to the instability of dentin-bonded restorations. Nevertheless, research on the development of etchants that can reduce acid damage is sparse. PURPOSE: The purpose of this in vitro study was to investigate the effects of polyvinylpyrrolidone-modified phosphoric acid on the dentin bonding of an etch-and-rinse adhesive. MATERIAL AND METHODS: Protective etchants were prepared by adding polyvinylpyrrolidone to 35% phosphoric acid aqueous solutions: the 3 concentrations were 0.5% (P0.5% group), 1% (P1% group), and 2% (P2% group) w/v. The treatment agent of the control group (C) was 35% phosphoric acid gel. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), microhardness, microtensile bonding strength (µTBS), nanoleakage, and in situ zymography were used to evaluate the appearance of the protective etchant on dentin bonding. The results were analyzed with a 1-way ANOVA test (α=.05). RESULTS: SEM showed no obviously exposed collagen fiber in the P1% and P2% groups. FTIR showed less demineralization of the dentin surface, and microhardness was higher after treatment with the protective etchant (P<.05). The µTBS of P1% (70 ±9.2 MPa) was the highest, and group C (44 ±5.8 MPa) was the lowest in all groups (P<.05). Moreover, there was weaker MMP activity in the P1% and P2% groups (P<.05). CONCLUSIONS: This study demonstrated that the protective etchant effectively reduced demineralization, enhanced bond strength, and reduced nanoleakage and enzyme activity within the hybrid layer.

Porous polyelectrolyte frameworks: synthesis, post-ionization and advanced applications.

Porous organic polymers (POPs), which feature high surface areas, robust skeletons, tunable pores, adjustable functionality and versatile applicability, have constituted a designable platform to develop advanced organic materials. Endowing polyelectrolytes with the distinct characteristics of POPs will attract mounting interest as the structural diversity of polyelectrolytes will bring the new hope of intriguing applications and potential benefits. In this review, the striking progress in ionized POPs (i-POPs) has been systematically summarized with regard to their synthetic strategies and applications. In the synthesis of i-POPs, we illustrate the representative ionic building blocks and charged functional groups capable of constructing the polyelectrolyte frameworks. The synthetic methods, including direct synthesis and post-modification, are detailed for the i-POPs with amorphous or crystalline structures, respectively. Subsequently, we outline the distinctive performances of i-POPs in adsorption, separation, catalysis, sensing, ion conduction and biomedical applications. The survey concerns the interplay between the surface chemistry, ionic interaction and pore confinement that cooperatively promote the performance of i-POPs. Finally, we conclude with the remaining challenges and promising opportunities for the on-going development of i-POPs.

Formulating an altered dentin substrate to improve dentin bonding.

STATEMENT OF PROBLEM: Secondary caries is a major factor in the failure of dental restorations. However, studies on the fabrication of acid-resistant and antibacterial dentin to improve dentin bonding are sparse. PURPOSE: The purpose of this in vitro study was to compare the effects of 2 types of fluoride-containing etchants on dentin bonding and explore the feasibility of formulating an altered dentin substrate to improve dentin bonding. MATERIAL AND METHODS: NaF-containing and SnF2-containing etchants were developed by adding sodium fluoride and stannous fluoride to a 35% phosphoric acid aqueous solution. Two groups (N1 and N2) containing NaF, 10 and 30 mg/mL respectively, and 2 groups (S1 and S2) containing SnF2, 18.6 and 55.8 mg/mL respectively, were formulated. The etchant of the control group (C) was 35% phosphoric acid gel. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), Fourier transform infrared spectroscopy (FTIR), microhardness, antierosion, and antibacterial tests were performed on the treated dentin. Moreover, the microtensile bond strength (µTBS) of each group was tested, and the fracture mode was determined after testing. Statistical analysis was performed with the 2-way ANOVA test (α=.05). RESULTS: The exposed collagen fiber was observed in group C, and minerals were formed on the dentin in the experimental groups. SEM, FTIR, and the microhardness test indicated more remineralization in the SnF2-containing etchant groups. The µTBS of S1 (77.5 ±10.36 MPa) was the highest in all groups, and group C (38.5 ±9.01 MPa) was the lowest. Moreover, the antierosion and antibacterial properties of the S2 group were the best among all groups (P<.05). CONCLUSIONS: Compared with NaF-containing etchant, SnF2-containing etchant could improve the dentin substrate, increase remineralization, improve bonding strength, and enhance antibacterial ability, especially by increasing resistance to acid erosion.

Bonding effect of a Zr/Si coating prepared on zirconia using a sol-gel method.

STATEMENT OF PROBLEM: Zirconia has been widely used as a dental prosthetic material. However, bonding to zirconia is challenging, and whether a Zr/Si coating would improve bonding is unclear. PURPOSE: The purpose of this in vitro study was to prepare a Zr/Si coating on zirconia ceramics using a sol-gel method and to determine whether the bonding to resin is improved. MATERIAL AND METHODS: Presintered zirconia specimens were prepared and divided into 5 groups: 4 experimental groups with ratios of the binary sol-gel precursor (zirconium oxychloride/tetraethoxysilane) set as 2:1 (Z2), 1:1 (Z1), 0.5:1 (Z0.5), and 0.25:1 (Z0.25) and Group C as the control group. In addition to surface roughness measurements, scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD) were carried out to characterize the surface. Each group was divided into 2 subgroups according to whether a silane coupling agent was applied. Half of the bond specimens were stored in deionized water for 24 hours; the remaining half were aged using 5000 thermocycles. The shear bond strength (SBS) of resin bonded to specimens was tested for the initial and durable bond strength, and the bonding interface was also observed by SEM after debonding. Data were subjected to 1-way ANOVA and the post hoc Tukey honestly significant difference test (α=.05). RESULTS: The Zr/Si coating formed on zirconia ceramics. Z0.5 had the greatest mean ±standard deviation roughness (2.13 ±0.15 µm) and had the highest silicon content (21.7 ±0.21%). t-ZrO2, m-ZrO2, c-SiO2, and ZrSiO4 were detected by XRD in Z1. The SBS values were decreased by aging but were significantly increased by Zr/Si coating, especially for Z0.5, with the application of silane (initial: 22.92 ±2.79 MPa; aged: 9.91 ±0.92 MPa). CONCLUSIONS: The Zr/Si coating significantly improved the initial and aged bond strength, and the optimal Zr/Si ratio of the sol-gel appeared to be 0.5:1.

Use of the Hall Technique by dentists in East China: A questionnaire-based cross-sectional survey.

BACKGROUND: The Hall Technique (HT) is now regarded as one of the biological management options for carious primary molars and has shown significant clinical success. AIM: To investigate the perception and the use of the HT among dentists engaging in paediatric dentistry in East China. DESIGN: This was an electronic questionnaire-based cross-sectional study. A quick response code of the questionnaire via WeChat, a common communication tool in China, was sent to dentists in East China. RESULTS: A total of 313 dentists participated in this study. Most surveyed clinicians had heard about the HT (n = 286, 91.4%). Of them, 40.2% (n = 115) reported having used the HT. Of 67 dentists working in private clinics, 34 (50.7%) had used the HT, whereas only 37% of dentists from public hospitals had used the HT. Of 115 dentists having used the HT, 91.3% (n = 105) would consider using the HT for Class II cavitated molars; 23.5% (n = 27) would consider using the HT for Class I cavitated molars. Most dentists who had not used the HT were concerned about complications such as pulp inflammation or necrosis after applying the HT. CONCLUSION: The HT is well known in East China; the lack of systematic training or courses, however, may decrease its utilization.

Mechanical and antibacterial properties of polymethyl methacrylate modified with zinc dimethacrylate.

STATEMENT OF PROBLEM: Polymethyl methacrylate (PMMA) has been widely used for denture base resin. However, concerns associated with PMMA, such as poor mechanical strength, high roughness, and porosity promoting microbial adhesion have been voiced; appropriate modification of PMMA denture base resin may improve its clinical application. PURPOSE: The purpose of this in vitro study was to investigate the effect of zinc dimethacrylate (ZDMA) modification on the mechanical and antibacterial properties of PMMA. MATERIAL AND METHODS: ZDMA at different mass fractions was mixed into PMMA as the experimental group, and unmodified PMMA was the control group. X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and the degree of conversion (DC%) were applied for characterization. Mechanical properties were measured with the 3-point bend test (n=10). The Streptococcus mutans biofilm model was used to investigate the antibacterial property by using colony-forming unit counts, metabolic activity, live/dead staining, quantitative real-time PCR (qRT-PCR), and SEM (n=5). The cell counting kit (CCK)-8 test was used to evaluate cytotoxicity. Data were subjected to analysis of variance and the post hoc Tukey honestly significant difference test (α=.05). RESULTS: SEM-EDS and XRD analysis revealed successful ZDMA incorporation into the PMMA matrix. DC% increased with the mass fraction of ZDMA, and no significant differences in DC% values were found among each tested group (P=.554). ZDMA mass fraction at 1 wt%, 2.5 wt%, and 5 wt% enhanced its mechanical properties, but those at 7.5 wt% and 10 wt% were reduced. The results of antibacterial experiments showed that ZDMA-modified PMMA displayed antibiofilm capabilities. Quantitative real-time PCR indicated that the expression levels of tested genes were significantly suppressed and that CCK-8 test indicated no cytotoxicity. CONCLUSIONS: ZDMA-modified PMMA exhibited antibacterial properties without its mechanical properties being affected. ZDMA is a potential metal crosslinking monomer for the modification of PMMA denture base resin.

Co-delivery of gemcitabine and cisplatin via Poly (L-glutamic acid)-g-methoxy poly (ethylene glycol) micelle to improve the in vivo stability and antitumor effect.

PURPOSE: The intention of the study was to co-delivery gemcitabine and cisplatin with totally different nature by prodrug and micelle strategy to improve its in vivo stability and antitumor effect. METHODS: A prodrug of gemcitabine (mPEG-PLG-GEM) was synthesized through the covalent conjugation between the primary amino group of gemcitabine and the carboxylic group of poly (L-glutamic acid)-g-methoxy poly (ethylene glycol) (mPEG-PLG). It was prepared into micelles by a solvent diffusion method, and then combined with cisplatin through chelation to prepare gemcitabine and cisplatin co-loaded mPEG-PLG micelles (mPEG-PLG-GEM@CDDP micelles). RESULTS: Gemcitabine and cisplatin in each micelle group were released more slowly than in solutions. In addition, pharmacokinetics behaviors of them were improved after encapsulated in prodrug micelles. T1/2z of gemcitabine and cisplatin encapsulated in micelles were prolonged to 6.357 h (mPEG-PLG-GEM), 10.490 h (mPEG-PLG@CDDP), 5.463 h and 12.540 h (mPEG-PLG-GEM@CDDP) compared with GEM@CDDP solutions (T1/2z = 1.445 h and 7.740 h). The ratio of synergy between gemcitabine and cisplatin (3:1 ~ 1:1(n/n)) was guaranteed in the systemic circulation, thus improving its antitumor effect. The results of biochemical analysis showed that GEM@CDDP-Sol was more toxic to kidneys and marrow compared with mPEG-PLG-GEM@CDDP micelles. CONCLUSIONS: By prodrug strategy, gemcitabine and cisplatin with totally different nature were prepared into micelles and obtained a better pharmacokinetic behavior. And the dual drug delivery system performed a better in vivo stability and antitumor effect compared with each single drug delivery system in the experiment. Scheme. Schematic of mPEG-PLG-GEM@CDDP micelles' formation and action process.

Simulation of the In Vivo Fate of Polymeric Nanoparticles Traced by Environment-Responsive Near-Infrared Dye: A Physiologically Based Pharmacokinetic Modelling Approach.

The application of physiologically based pharmacokinetic models to nanoparticles is still very restricted and challenging, owing to the complicated in vivo transport mechanisms involving nanoparticles, including phagocytosis, enhanced permeability and retention effects, cellular recognition, and internalisation, enzymatic degradation, lymphatic transport, and changes in physical properties. In our study, five nanoparticle formulations were synthesised using polycaprolactone as a framework material and methoxy poly (ethylene glycol)-poly(ε-caprolactone) as a long-circulating decorating material, as well as types of environmentally responsive near-infrared aza-boron-dipyrromethene dyes. According to quantification data and direct visualisation involving specific organs, a phagocytosis physiologically based pharmacokinetic model was developed to describe the dynamics of nanoparticles within and between organs in mice, considering cellular mechanisms involving phagocytosis and enhanced permeability and retention effects. Our results offer a better understanding of the in vivo fate of polymeric nanoparticles.

Enhanced Delivery of Radiolabeled Polyoxazoline into Tumors via Self-Aggregation under Hyperthermic Conditions.

In order to develop a radiopharmaceutical for internal radiotherapy that had a high anticancer effect while exposing normal tissues to low radiation levels, we synthesized a radiolabeled polyoxazoline (POZ), a thermoresponsive polymer, and established a novel drug delivery system for targeting tumors by accelerating the accumulation of the radiolabeled POZ via self-aggregation under hyperthermic (42-43 °C) conditions. By living-cationic polymerization using 2-ethyl-2-oxazoline and 2-isopropyl-2-oxazoline, POZ derivatives (Et-IspPOZ) (10, 20, and 30 kDa) with lower critical solution temperatures (LCSTs) of 37-38 °C were synthesized; the POZ derivatives were soluble at the body temperature but self-aggregated upon heat treatment (42-43 °C). Next, the indium-111 (111In)-labeled Et-IspPOZ was prepared, and the effect of molecular weight and injected POZ dose on the accumulation of radioactivity in the tumors was investigated upon intravenous injection of probes under hyperthermic conditions in colon 26-bearing mice. The uptake of radioactivity in tumors was increased when the molecular weight of POZ was greater than 20 kDa, while it was independent of the injected POZ dose (4-40 nmol). The amount of radioactivity retained in the tumor did not change for up to 3 h after exposure to heat treatment was stopped. Furthermore, the tumor uptake of the Et-IspPOZ derivative with an LCST greater than 42 °C was significantly lower than that of Et-IspPOZ, which had an LCST of 37-38 °C, suggesting the involvement of the self-aggregation of POZ on tumor uptake. Finally, the intratumoral localization of fluorescence-labeled Et-IspPOZ was evaluated using in vivo confocal laser microscopy. Many bright fluorescence spots were observed in the heat-treated tumors nearby and within blood vessels. In conclusion, the high tumor uptake of radiolabeled Et-IspPOZ was elucidated under hyperthermic conditions; thereby, the possibility of developing a novel internal radiotherapy using radiolabeled POZ derivatives was demonstrated.

Improving Plasma Stability and Bioavailability In Vivo of Gemcitabine Via Nanoparticles of mPEG-PLG-GEM Complexed with Calcium Phosphate.

PURPOSE: Despite being widely used for the treatment of several solid tumors, Gemcitabine (GEM) exhibits several suboptimal pharmacokinetic properties. Therefore, the design of nanoparticle delivery systems is a promising strategy to enhance GEM pharmacokinetic properties. METHODS: In this work, the polymeric material methoxy poly(ethylene glycol)-block-poly(L-glutamic acid)-graft-gemcitabine (mPEG-b-PLG-g-GEM) was synthesized through the covalent conjugation of GEM with the carboxylic group of methoxy poly(ethylene glycol)-block-poly (L-glutamic acid) (mPEG-b-PLG) (mPEG113, Mn = 5000). mPEG-PLG-GEM/CaP nanoparticles were prepared through the simple mixing of calcium and phosphate/mPEG-PLG-GEM solutions. mPEG-PLG-GEM was embedded in the calcium phophate (CaP) backbone via electrostatic interactions. RESULTS: After incubation in plasma at 37°C for 24 h, gemcitabine was degraded by 24.6% for the mPEG-PLG-GEM, 14.7% for the mPEG-PLG-GEM/CaP nanoparticles, and 90% for the free gemcitabine solution. It was observed that mPEG-PLG-GEM and mPEG-PLG-GEM/CaP improved the area-under-curve (AUC) values by 5.26-fold and 6.33-fold compared to free drug, respectively. CONCLUSION: The amide bond linked gemcitabine polymers was able to protect GEM from cytidine deaminase degradation in vivo, and the skeleton formed by the calcium phosphate enhanced the stability and prolonged the half-life of GEM. Importantly, mPEG-PLG-GEM/CaP nanoparticles elevated the GEM plasma concentration in an animal model.

Label-Free LSPR Detection of Trace Lead(II) Ions in Drinking Water by Synthetic Poly(mPD-co-ASA) Nanoparticles on Gold Nanoislands.

Using self-assembly gold nanoislands (SAM-AuNIs) functionalized by poly(m-phenylenediamine-co-aniline-2-sulfonic acid) (poly(mPD-co-ASA)) copolymer nanoparticles as specific receptors, a highly sensitive localized surface plasmon resonance (LSPR) optochemical sensor is demonstrated for detection of trace lead cation (Pb(II)) in drinking water. The copolymer receptor is optimized in three aspects: (1) mole ratio of mPD:ASA monomers, (2) size of copolymer nanoparticles, and (3) surface density of the copolymer. It is shown that the 95:5 (mPD:ASA mole ratio) copolymer with size less than 100 nm exhibits the best Pb(II)-sensing performance, and the 200 times diluted standard copolymer solution contributes to the most effective functionalization protocol. The resulting poly(mPD-co-ASA)-functionalized LSPR sensor attains the detection limit to 0.011 ppb toward Pb(II) in drinking water, and the linear dynamic range covers 0.011 to 5000 ppb (i.e., 6 orders of magnitude). In addition, the sensing system exhibits robust selectivity to Pb(II) in the presence of other metallic cations as well as common anions. The proposed functional copolymer functionalized on AuNIs is found to provide excellent Pb(II)-sensing performance using simple LSPR instrumentation for rapid drinking-water inspection.

Effect of airborne-particle abrasion of presintered zirconia on surface roughness and bacterial adhesion.

STATEMENT OF PROBLEM: Factors associated with implant periodontal disease of zirconia restorations such as surface roughness remain largely unknown. PURPOSE: The purpose of this study was to investigate how airborne-particle abrasion before sintering affects roughness and bacterial adhesion on the surface of zirconia. MATERIAL AND METHODS: Thirty presintered zirconia specimens were divided into 6 groups of 5 after being polished with silicon carbide paper (1200 grit). A different surface treatment was applied to each group (no treatment [group Ct] and 120-µm alumina abrasion for 5, 8, 10, 12, and 15 seconds [A5s, A8s, A10s, A12s, and A15s]), and the specimens were then densely sintered. The mean centric linear roughness (Ra) was measured, and the 3D measurement of surface roughness (3D roughness) was determined. The number of colony forming units (CFUs) of Streptococcus mutans adhering to the surface was also examined. One-way ANOVA was used for data analysis (α=.05). RESULTS: Airborne-particle abrasion before sintering significantly increased surface roughness. Group A8s, A10s, A12s, and A15s showed statistically significant higher CFU/mL than did group A5s (P<.05). No difference was found in CFU/mL between group Ct and A5s (P=.230). CONCLUSIONS: Airborne-particle abrasion before sintering is a useful method of increasing the surface roughness of zirconia. Ra < 0.58 µm is necessary to inhibit the adherence of S. mutans to zirconia.

Safety and efficacy of bevacizumab combined with R-CHOP regimen in seven Chinese patients with untreated diffuse large B-cell lymphoma.

BACKGROUND: Rituximab plus CHOP (R-CHOP) significantly improved the outcome of diffuse large B cell lymphoma (DLBCL), a common sub-type of non-Hodgkin lymphoma. But 40% - 50% of DLBCL patients cannot be cured by this regimen. Some clinical trials showed that bevacizumab might be useful in the treatment of DLBCL. This study evaluated the safety and efficacy of bevacizumab combined with the R-CHOP (A-R-CHOP) regimen in Chinese patients with previously untreated DLBCL. METHODS: Patients with previously untreated DLBCL received A-R-CHOP regimen therapy. All patients with complete response (CR)/ unconfirmed complete response(CRu) after 8 cycles of A-R-CHOP received the bevacizumab maintenance therapy once every 3 weeks. The remained bulky disease was treated with radiotherapy. RESULTS: Seven Chinese patients were treated. All of them had bulky diseases. One patient had progressive disease after 4 cycles of A-R-CHOP therapy. The rest six patients completed 8 cycles of A-R-CHOP treatment. All of these six patients reached CR/CRu (5 CR, 1 CRu). Bevacizumab maintenance therapy was given to 4 CR patients. All 7 patients experienced Grade 3/4 hematologic adverse events; additionally, one had Grade 3 gastrointestinal toxicity and one had Grade 1 epistaxis. During bevacizumab maintenance therapy, one patient had Grade 1 gingival bleeding, another experienced Grade 1 proteinuria and then Grade 3 congestive heart failure 4 months after completion of maintenance therapy. At the end of July 2013, the patient who had progressive disease after 4 cycles of A-R-CHOP died of progressive disease, the other six remained CR response. CONCLUSIONS: The A-R-CHOP regimen is effective for untreated DLBCL, but may cause bevacizumab-specific toxicities, which should be monitored.

Effect of microplastics on sodium hypochlorite disinfection and changes in its toxicity on zebrafish.

The presence of microplastics (MPs) in water may affect the efficacy of the disinfection process and induce toxicity changes to MPs themselves during disinfection. Therefore, this study evaluated the two-way effects of polyethylene microplastic (MP) particles in water and wastewater during sodium hypochlorite (NaClO) disinfection. On the one hand, it has been confirmed that the presence of MPs reduced the disinfection efficiency of NaClO. The required CT (concentration of the disinfection × contact time) for a 2-4-log inactivation of Escherichia coli (E. coli) in different water samples was in the order of deionized water < turbid water (1 NTU) < water with MPs (1 mg/L) < turbid water (10 NTU). On the other hand, although exposure to MPs did induce significant changes in the activities of superoxide dismutase and glutathione, compared to pristine MPs, the MPs treated by NaClO at current conditions (0.3 and 3.0 mg/L for 30 min) did not show significant changes in their toxicity on zebrafish, at an MP exposure concentration of 1 mg/L. There was no significant difference in the survival rate and weight growth rate, neither as in the activities of the oxidative stress-related enzymes (superoxide dismutase, catalase, glutathione, glutathione peroxidase, and glutathione s-transferase) in both gut and muscle tissues of the zebrafish, between exposure to the pristine and NaClO-treated MPs. It is indicated that NaClO disinfection commonly applied for water and wastewater treatment would not pose a serious concern to effluent safety in the presence of mild levels of MPs.

Polyvinylpyrrolidone as a primer for resin-dentin bonding.

OBJECTIVE: This study aimed to investigate the effects of polyvinylpyrrolidone (PVP)-containing primer (PCP) on dentin bonding. METHODS: PVP and anhydrous ethanol were used to prepare the PCPs, which were prepared at concentrations of 0.5%, 1%, and 2% (w/v). These PCPs were subsequently applied to the dentin surface, denoted as E1, E2, and E3, respectively. In the control group, no primer was applied. Following the treatment, the dentin surfaces were subjected to analysis using Fourier-transform infrared spectroscopy (FTIR), and the micro-tensile bond strength (MTBS) was evaluated. The failure mode, nanoleakage, and bonding longitudinal section were observed utilizing scanning electron microscopy (SEM). Additionally, the effect of PCPs on matrix metalloproteinases (MMPs) activity was analyzed through an in situ zymography test. Data were subjected to statistical analysis using ANOVA tests (α = 0.05). RESULTS: Significant alterations in the infrared resonances associated with collagen cross-linking within the collagen matrix were observed across all PCP groups. The application of PCP demonstrated a noteworthy enhancement in micro-tensile bond strength (MTBS) compared to group C (p < 0.05). Notably, group C exhibited the lowest MTBS (41 ± 7.7 MPa), whereas group E2 demonstrated the highest MTBS (66 ± 11.9 MPa). Even after undergoing aging, the MTBS of the PCP groups remained superior to that of group C (p < 0.05). The resin tag length in the PCP groups was found to be greater than that of group C, and the occurrence of nanoleakage was comparatively lower in the PCP groups, both before and after aging. Additionally, PCP exhibited a dose-dependent inhibition of matrix metalloproteinases (MMPs) activity, which was statistically significant (p < 0.05). CONCLUSIONS: The utilization of PCP Primer exhibits notable enhancements in bond strength, mitigates nano-leakage, and suppresses enzyme activity within the hybrid layer.

Photothermal modulation of gingival fibroblasts via polydopamine-coated zirconia: A novel approach for promoting peri-implant soft tissue integration.

Achieving robust soft tissue integration around dental implants is crucial for long-term clinical success, as it forms a protective biological seal against bacterial invasion. However, the soft tissue attachment to implants is relatively deficient compared to natural teeth, particularly in the connective tissue region lacking sufficient gingival fibroblasts and collagen fiber alignment. This study proposed an innovative strategy to enhance peri­implant soft tissue integration by modulating gingival fibroblast behavior via photothermal conversion. Zirconia surfaces were coated with polydopamine (PDA), a melanin-like polymer exhibiting near-infrared (NIR) absorption for photothermal conversion. Under NIR irradiation, the PDA coating enabled mild hyperthermia (42-43 °C) on the zirconia surface. Remarkably, this mild photothermal stimulation significantly promoted human gingival fibroblast proliferation, adhesion, and collagen production compared to unmodified zirconia in vitro. By utilizing the photothermal properties of PDA coatings to modulate cellular behaviors beneficial for connective tissue formation, this approach provides a promising avenue to achieve improved soft tissue integration and long-term stability of dental implants. The findings highlight the innovative potential of combining biomaterial surface engineering with photothermal therapy for applications in implant dentistry.

[Detection of oral fungal flora in patients with primary Sjogren's syndrome by real-time PCR].

OBJECTIVE: To compare the quantity of the main important Candida species in the oral cavity between the patients with primary Sjogren's syndrome (pSS) and no dry mouth healthy controls,and to explore the discriminative species of fungi between the two groups. METHODS: In this study, 25 pSS patients from Department of Oral Medicine of Peking University School and Hospital of Stomatology were enrolled, with 25 residents from a community in Beijing as the control group. All the participants were examined for the oral mucosa status, and 5 Candida DNA loads were compared between the two groups by use of the FQ-PCR technique. RESULTS: Candida albicans was the dominant Candida in both of the groups. In addition, we found that the species of Candida tropicalis and Parapsilosis were more detected in the pSS group by use of the FQ-PCR technique. Quantitative of Candida tropicalis and Candida parapsilosis in pSS group (10.6 ± 1.07, 9.47 ± 4.86) was significantly higher than that in healthy controls group (8.30 ± 3.82, 5.24 ± 6.05), the difference was statistically significant (P <0.05). Quantitative of fluconazole-sensitive strains in pSS group (12.21 ± 0.82) compared with which in healthy controls group (11.53 ± 0.81) was significantly increased (P <0.01). CONCLUSION: Candida albicans was the dominant Candida in both of the groups. Candida tropicalis and Candida parapsilosis were more detected in the pSS group.

Polycrystalline particulates synthesized on zirconia for enhanced bioactivity: An in vitro study.

Zirconia is a promising material for dental implant with its excellent biocompatibility, good mechanical properties, and esthetic effect similar to natural teeth. To improve the bioactivity and osteogenic properties of zirconia, pre-sintered zirconia discs were divided into C, T3 , T5 , and T7 group. Group C was as control. T3 , T5 , and T7 groups were soaked in hydrofluoric acid (HF) for 30, 50, and 70 s, respectively. Then, they were placed into CaCl2 solution and heated in NaOH solution. After sintering, the samples were characterized by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction, which confirmed the ZrO2 polycrystalline particulates in situ synthesized on the treated sample discs. The surface roughness of the treated samples was increased with the prolonged of acid treatment time (p < .05), while the three-point bending strength did not decrease significantly (p > .05). MC3T3-E1 cells were cultured on zirconia discs to evaluate the bioactivity and osteogenic effect of modified zirconia. The living&dead fluorescence staining and CCK-8 assay showed that the specimens were non-toxic and significantly promoted cell proliferation. In addition, the cell proliferation was enhanced with the increase of zirconia surface roughness. Polycrystalline particles modified zirconia were beneficial to cell spreading. After osteogenic induction, MC3T3-E1 cells inoculated on modified zirconia exhibited higher alkaline phosphatase activity, mineralization activity and up-regulated osteogenesis-related gene expression. Above all, in situ synthesized polycrystalline particulates significantly improve the biological activity of zirconia, which will promote the widespread application of zirconia implants.

Biological properties of hydroxyapatite coatings on titanium dioxide nanotube surfaces using negative pressure method.

Titanium (Ti) exhibits superior biocompatibility and mechanical properties but is bioinert, while hydroxyapatite (HA) possesses excellent osteogenesis and is widely used for the modification of Ti surface coatings. However, the synthesis of homogeneous and stable HA on metallic materials is still a major challenge. In this study, porous titanium dioxide nanotube arrays were prepared on Ti surface by anodic oxidation, loaded with calcium and phosphorus precursors by negative pressure immersion, and HA coating was formed by in situ crystallization of calcium and phosphorus on the surface by hydrothermal heating. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and bonding strength were conducted to confirm the surface characteristics of each group. The cell proliferation, mineralization degree, and alkaline phosphatase (ALP) activity of MC3T3-E1 cells on samples were calculated and compared in vitro experiments. Cylindrical samples were implanted into rat femurs to evaluate biocompatibility and osteogenesis in vivo. The results showed that HA crystals successfully synthesized in TiO2 nanotubes, enhancing the bonding strength of HA coating and Ti substrate under negative pressure. Moreover, HA coating on Ti substrate remarkably enhanced cell proliferation and osteogenic differentiation activity in vitro, and improved new bone formation as well as osseointegration in vivo.