OBJECTIVE: To explore the influence of the thickness of mixed cardboard on the compressive strength of glass ionomer cement and the associated factors. METHODS: Three different types of glass ionomer cements were mixed on the top of 60, 40, 20 and 1 pieces of paper (P60, P40, P20 and P1), respectively. The compressive strength of the materials was tested after solidification, and the bubble rate was calculated with the assistance of scanning electron microscope. RESULTS: (1) Compressive strength: ① ChemFil Superior glass ionomer (CF): The average compressive strength of P1 group was the highest, which was significantly different from that of P40 and P60 groups (P values were 0.041 and 0.032 respectively); ② To Fuji IX GP glass ionomer (IX): The average compressive strength of P1 group was the highest, which was statistically different from that of P40 and P60 groups (P values were 0.042 and 0.038 respectively); ③ Glaslonomer FX-Ⅱ glass ionomer cement (FX): The average compressive strength of P1 group was the highest, which was statistically different from that of P20, P40 and P60 groups (P values were 0.031, 0.040 and 0.041 respectively), but there was no statistical difference among the other groups. All the three materials showed that the compressive strength of glass ions gradually increased with the decrease of the thickness of the blended paperboard, and the two materials had a highly linear negative correlation, the correlation coefficients of which were CF-0.927, IX-0.989, FX-0.892, respectively. (2) Scanning electron microscope: P1 group had the least bubbles among the three materials. CONCLUSION It indicates that the thickness of mixed cardboard has a negative correlation with the compressive strength of glass ions. The thicker the mixed cardboard is, the greater the elasticity is. Excessive elasticity will accelerate the mixing speed when the grinding glass ions. Studies have shown that the faster the speed of artificial mixing is, the more bubbles is produced.The thicker ther mixed cardboard is, the more bubblesn are generated by glass ionomer cement, and the higher the compressive strength is. Using one piece of paper board to mix glass ionomer cement has the least bubbles and can obtain higher compressive strength.
Compressive Strength ; Materials Testing ; Glass Ionomer Cements ; Silicon Dioxide

Bioactive glass (BG) has been widely used in the preparation of artificial bone scaffolds due to its excellent biological properties and non-cytotoxicity, which can promote bone and soft tissue regeneration. However, due to the brittleness, poor mechanical strength, easy agglomeration and uncontrollable structure of glass material, its application in various fields is limited. In this regard, most current researches mainly focus on mixing BG with organic or inorganic materials by freeze-drying method, sol-gel method, etc., to improve its mechanical properties and brittleness, so as to increase its clinical application and expand its application field. This review introduces the combination of BG with natural organic materials, metallic materials and non-metallic materials, and demonstrates the latest technology and future prospects of BG composite materials through the development of scaffolds, injectable fillers, membranes, hydrogels and coatings. The previous studies show that the addition of BG improves the mechanical properties, biological activity and regeneration potential of the composites, and broadens the application of BG in the field of bone tissue engineering. By reviewing the recent BG researches on bone regeneration, the research potential of new materials is demonstrated, in order to provide a reference for future related research.
Bone Regeneration ; Bone and Bones ; Freeze Drying ; Glass ; Hydrogels

ABSTRACT High viscous glass ionomer cement (HVGIC) was recently developed for atraumatic restorative treatment (ART). However, its moisture sensitivity remains a limitation thus protective coating application is recommended. This study investigated the effect of resin coating on the surface roughness and microhardness of two HVGICs (Riva Self Cure HVGIC [RV] and Equia® Forte Fil [EQ]) conditioned in food-simulating liquids (FSLs). Fifty standard disc-shaped samples were fabricated using customised stainless-steel mould (10 × 2 mm). Coating was applied on top surface of all samples and subsequently divided into five groups: air (control), distilled water, 0.02 N citric acid, heptane and 50% ethanol-water solution. The samples were conditioned in FSLs at 37°C for seven days. Subsequently, the surface roughness and microhardness of samples were measured using optical profilometry and microhardness tester, respectively. SEM analysis was done for qualitative observation of surface morphological changes. Data were analysed using one-way ANOVA, two-way ANOVA and posthoc Tukey’s test (α = 0.05). Interestingly, the results revealed that surface roughness was significantly influenced by FSLs immersion, presence of coating and the materials itself (p < 0.001). The lowest surface roughness was found on control coated samples: RV (50.98±4.25) nm and EQ (62.77±3.92) nm, while the highest values seen on uncoated surfaces in citric acid: RV (505.26±31.10) nm and EQ (350.33±15.36) nm. RV samples had the lowest microhardness of 54.97±2.48 Vickers hardness number (VHN) post-immersion in citric acid. In conclusion, with the exception of RV conditioned in heptane and ethanol, the uncoated HVGICs generally had higher surface roughness than the coated HVGICs. HVGICs conditioned in citric acid showed the most significant increase in surface roughness and reduction in microhardness.
Glass Ionomer Cements--adverse effects

PURPOSE: We used a questionnaire to explore perceptions and clinical practice patterns of Korean pediatric ophthalmologists in terms of amblyopia.METHODS: From September to November 2018, we conducted a web-based questionnaire survey of 99 specialists of the Korean Association for Pediatric Ophthalmology and Strabismus who operated ophthalmology clinics in Korea. We received 56 responses (56.57%) and retrospectively analyzed the data.RESULTS: The average specialist age was 44.0 ± 9.7 years. The mean age of treated amblyopia patients was 3 to 5 years (69.6%); the most common amblyopia was refractive anisometropic amblyopia (75.0%). On average, treatment commenced at 4 years of age (53.6%); child and parent co-operation most significantly influenced treatment success (46.4%). The preferred test was cycloplegic refraction (96.4%) and the preferred treatment occlusion therapy (100%) with glasses correction (98.2%). Occlusion therapy was most commonly performed for 2 hours/day (69.6%); the minimum age for eyeglasses prescription was 2.10 ± 1.18 years. Only three respondents (5.36%) prescribed contact lenses and only one (1.79%) performed refractive surgery.CONCLUSIONS: In Korea, amblyopia treatment is based on occlusion therapy and glasses correction. However, the time of treatment commencement, the duration of occlusion therapy, and the glasses used for correction varied. It is necessary to develop guidelines for amblyopia treatment; these should reflect current medical conditions.
Amblyopia ; Child ; Contact Lenses ; Eyeglasses ; Glass ; Humans ; Korea ; Ophthalmology ; Parents ; Practice Patterns, Physicians' ; Prescriptions ; Refractive Surgical Procedures ; Retrospective Studies ; Specialization ; Strabismus ; Surveys and Questionnaires

PURPOSE: We developed a novel method for measurement of hyperacuity and verified the utility thereof.METHODS: We developed a three-dimensional (3D) hyperacuity test using a 3D liquid crystal flat screen, a left- and right-image polarized display, and liquid crystal shutter glasses. We tested the technique in three groups: normal (n = 48), with cataracts (n = 14), and with macular disease (n = 35). We used a chart consisting of five dots and a reference line. Of the five dots, one was variably shifted from the other dots. A chart was presented to one eye and the reference line or blank image to the other eye; a subject scored positive when the dot in the unusual position was recognized.RESULTS: Hyperacuity was measured in terms of the reference line seen by the reference eye (RR), a blank image seen by the reference eye (RB), the reference line seen by the contralateral eye (CR), and a blank image seen by the contralateral eye (CB). All test scores were significantly lower when the reference line was seen than not (RR vs. RB and CR vs. CB; p < 0.01, respectively). For the RR and CR tests, no significant difference was apparent between the normal and cataracts group (p = 0.553, p = 0.494) but such differences were evident between the normal and macular disease groups (p = 0.028, p = 0.002). Also, visualization of the reference line by the reference and contralateral eyes did not differ (p > 0.05).CONCLUSIONS: Measurement of hyperacuity using our new method was not affected by media opacity but was significantly affected by macular disease. Presentation of a reference line facilitated hyperacuity assessment.
Cataract ; Eyeglasses ; Glass ; Liquid Crystals ; Methods

OBJECTIVE: To study the effect of bioactive glass (BG) on the dentin bond strength and the microleakage of hybrid layer. METHODS: In the study, 30 dentin planes were prepared from the third molars with no caries and equally assigned to the control group, BG group, and sodium trimetaphosphate (STMP)-polyacrylic acid (PAA)-BG group (S-P-BG group), randomly. After etched with 35% phosphoric acid, the dentin planes of BG group were pretreated with 0.5 g/L BG, and the dentin planes of S-P-BG group were pretreated with 5% STMP, 5% PAA and 0.5 g/L BG. No additional pretreatment was done to the dentin planes of control group. Then the dentin planes were bonded using 3M Single Bond 2 adhesive to 3M Z350XT composite resin, and cut into 0.9 mm×0.9 mm column samples, which were stored at 37 ℃ artificial saliva (AS). After 24 hours, 1 month, and 3 months, the microtensile bond strength test was performed. The data were analyzed using one-way ANOVA and LSD method. The morphology of the bond fracture interface was observed with scanning electron microscope. Other 27 teeth were collected and the enamel layer and roots cut off, with the pulp chamber exposed. 0.1% rhodamine B was added to the 3M Single Bond 2 adhesive, and then the adhesive was applied to complete the bonding procedures as above. The teeth were stored in 37 ℃ AS for 24 hours, 1 month, 3 months, and then 0.1% sodium fluorescein solution was placed in the chambers and stained for 1 hour. Confocal laser scanning microscopy was used to observe the interface morphology and microleakage of the hybrid layer. RESULTS: At the end of 24 hours and 1 month, there was no significant difference in the microtensile bond strength among the three groups (P>0.05). After 3 months of soaking, the S-P-BG group [(36.91±7.07) MPa] had significantly higher microtensile bond strength than the control group [(32.73±8.06) MPa] (P=0.026); For the control group and the BG group, the microtensile bond strength significantly decreased at the end of 3 months compared with 24 hours (control group: P=0.017, BG group: P=0.01); The microtensile bond strength of S-P-BG group af the end of 3 months had no significant difference in compared with 24 hours [(37.99±7.98) MPa] (P>0.05). Observation of the fracture surface at the 24 hours showed no obvious mineralization in all the three groups. After 1 and 3 months, mineral formation was observed in BG group and S-P-BG group, and no obvious collagen exposure was observed in S-P-BG group. Confocal laser scanning microscopy revealed no obvious differences in the morphology and quantity of the resin tag in the control group, BG group and S-P-BG group. At the end of 24 hours, leakage was found in all the three groups. The microleakage of the control group increased at the end of 3 months, while the microleakage of the BG and S-P-BG groups decreased. CONCLUSION BG pretreatment of dentin bonding interface can induce mineralization at the bonding interface and reduce the microleakage of the hybrid layer; pretreating the dentin bonding interface with STMP, PAA and BG may enhance the maintaining of the dentin bonding durability.
Dentin ; Dentin-Bonding Agents ; Glass ; Resin Cements ; Tensile Strength

OBJECTIVE: To compare the residual cement between computer aided design/computer aided manufacturing customized abutments (CCA) and stock abutments (SA), and to evaluate the feasibility of digital measurement for residual cement volume by three-dimensional scanning. METHODS: Twenty master models needed in this study were all taken from one 47-year-old patient with arrested periodontitis, who had already had an implant placed at his right upper central incisor site in the Department of Periodonto-logy, Peking University School and Hospital of Stomatology. After 4 weeks of soft tissue conditioning by means of customized healing abutment, the height of peri-implant soft tissue was measured, from the implant platform to mucosal margin, as 5 mm. Using customized impression coping, the impression was taken and twenty models were fabricated and allocated to 4 groups according to the type of abutments: CCA1 (5 mm transmucosal height CCA, with margin at tissue level), CCA2 (4 mm transmucosal height CCA, with 1 mm submucosal margin), SA1 (3 mm transmucosal height SA, with 2 mm submucosal margin) and SA2 (1 mm transmucosal height SA, with 4 mm submucosal margin). Crowns were cemented to the abutments, which were seated on the working models. Excess cement was removed by a prosthodontic specialist. Thereafter, the volume of residual cement was evaluated by using three-dimensional scanning technique. The area proportion of residual cement was calculated on photographs taken by a single lens reflex camera. The weight of residual cement was weighed by an analytical balance. And the correlation of residual cement volume data with residual cement area proportion or weight of residual cement acquired by traditional methods was analyzed. RESULTS: Residual cement was observed on all the experiment samples. The residual cement volume of CCA was significantly less than that of SA [(0.635 3±0.535 4) mm³ vs. (2.293 8±0.943 8) mm³, P < 0.001]. Consistently, CCA had less residual cement area proportion and weight than those of SA [area proportion: 7.57%±2.99% vs. 22.68%±10.06%, P < 0.001; weight: (0.001 5±0.001 0) g vs. (0.003 7±0.001 4) g, P < 0.001]. The residual cement volume was strongly correlated with the residual cement area proportion and residual cement weight (r>0.75, P < 0.001). CONCLUSION These in vitro results suggest that CCA minimized the residual cement more effectively than SA. The method to digitally evaluate the residual cement volume is feasible, but its validity and reliability need to be further studied.
Aged, 80 and over ; Bone Cements ; Computer-Aided Design ; Crowns ; Dental Abutments ; Dental Prosthesis, Implant-Supported ; Glass Ionomer Cements ; Humans ; Reproducibility of Results

Fiber-reinforced resin composite posts (fiber posts) are used extensively for the restoration of root-treated teeth with excessive loss of coronal structure. However, the longevity of a fiber post restoration still needs to be improved because of the various confounding factors that affect bonding procedures. Operational specification for clinical use of dental intraradicular fiber post was established based on the in-depth discussions by a panel of experts from Society of Prosthodontics, Chinese Stomatological Association. This specification should be helpful in standardizing the clinical technique of fiber post placement and improving the clinical longevity of a fiber post restoration.
Cementation ; Composite Resins ; Dental Bonding ; Dental Stress Analysis ; Glass ; Materials Testing ; Post and Core Technique ; Resin Cements ; Tooth Root

PURPOSE: Allergic rhinitis is the most common atopic disease and the most common chronic disease of children. Eosinophil count and percentage in nasal smear are useful for differential diagnosis of allergic rhinitis. The aim of this study is to investigate the correlation between nasal eosinophil count and percentage.METHODS: Between January 2017 and August 2018, 221 children patients with a clinical history of rhinitis were tested at the outpatient respiratory and allergy unit of the Department of Pediatrics, School of Medicine, The Catholic University of Korea. Nasal secretion was collected by swabbing a children's nasal inferior turbinate 3–4 times with a cotton swab and then placed on to a glass slide. Later, the smear was stained by Giemsa stain.RESULTS: This is the first study to assess the comparison of nasal eosinophil count and percent. There is a positive correlation between nasal eosinophil count and percent Y=1.02 X+2.82 (Y=Eosinophil count, X=Eosinophil percentage). To determine the usefulness of nasal eosinophil count and percentage in the diagnosis of allergic rhinitis, we analyzed receiver operating characteristic curves. The cutoff value of the nasal eosinophil count was 6.5/high-power field, and that of the nasal eosinophil ratio was 3% for the diagnosis of allergic rhinitis.CONCLUSION: In patients with suspected rhinitis, one of the values of nasal eosinophil count or percentage can be used in clinical practice.
Azure Stains ; Child ; Chronic Disease ; Diagnosis ; Diagnosis, Differential ; Eosinophils ; Glass ; Humans ; Hypersensitivity ; Korea ; Outpatients ; Pediatrics ; Rhinitis ; Rhinitis, Allergic ; ROC Curve ; Turbinates

A diblock copolymer, poly(ethylene glycol) methacrylate-block-glycidyl methacrylate (PEGMA-GMA), was prepared on glass substrate by surface-initiated atom transfer radical polymerization (SI-ATRP), and endothelial specific peptide Arg-Glu-Asp-Val (REDV) was immobilized at the end of the PEGMA-GMA polymer brush by ring opening reaction through the rich epoxy groups in the GMA. The structure and hydrophilicity of the polymer brushes were characterized by static water contact angle, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results showed that the REDV modified copolymer brushes were successfully constructed on the glass substrates. The REDV peptide immobilized onto surface was quantitatively characterized by ultraviolet-visible spectroscopy (UV-VIS). The blood compatibility of the coating was characterized by recalcification time and platelet adhesion assay. The results showed that the polymer coating had good blood compatibility. The multifunctional active polymer coating with PEGMA and peptide produced an excellent prospect in surface construction with endothelial cells selectivity.
Biocompatible Materials ; Cells, Cultured ; Endothelial Cells ; Glass ; Humans ; Immobilized Proteins ; Methacrylates ; Oligopeptides ; Platelet Adhesiveness ; Polyethylene Glycols ; Polymers ; Surface Properties