Zirconia is widely used in the field of dentistry because of its superior mechanical and esthetic characteristics. However, the tetragonal zirconia polycrystal restorations commonly used in clinics will degrade at low temperatures in the oral environment, resulting in increased surface roughness, microcracks, and decreased mechanical properties. Low-temperature degradation of zirconia can be affected by grain size, stress, stabilizer content and type, surface treatment, sintering conditions, and other factors. Through a literature review and analysis, this review summarizes the research progress on the low-temperature degradation of zirconia in prosthetic dentistry to provide references for the improvement of zirconia in clinical and research applications.
Ceramics ; Dental Materials ; Esthetics, Dental ; Materials Testing ; Prosthodontics ; Surface Properties ; Temperature ; Yttrium/chemistry* ; Zirconium

Objective: To evaluate the effects of pre-sintering heating rate and powder size on dental recycled zirconia. Methods: Recycled zirconia powders were sieved to obtain the large (50 μm With the same particle size, the recycled zirconia pre-sintered at different heating rates showed no significant differences in the relative densities, and the open porosities (P>0.05). When the pre-sintering heating rates were 2 ℃/min, 5 ℃/min, and 8 ℃/min, the flexural strengths of the large-particle recycled zirconia were (421.2±54.7), (444.2±70.1) and (427.5±68.4) MPa, the flexural strengths of the small-particle recycled zirconia were (750.1±74.1), (777.2±95.5) and (746.7±73.0) MPa, respectively. The flexural strength of commercial zirconia was (988.4±129.8) MPa. The flexural strengths of the recycled zirconia were significantly lower than that of the commercial zirconia (P<0.05). At the same pre-sintering heating rate, the flexural strengths of the small-particle recycled zirconia were significantly higher than that of the large-particle recycled zirconia (P<0.05). Conclusions: Compared with the large particles, small-particle recycled zirconia powders can effectively improve the properties of recycled zirconia, while the pre-sintering heating rate has no effect on the properties of the recycled zirconia.
Ceramics ; Dental Materials/chemistry* ; Heating ; Materials Testing ; Powders ; Surface Properties ; Yttrium ; Zirconium

OBJECTIVE: To evaluate the effects of femtosecond laser treated microgrooved surface on microscopic topography, phase transformation, and three-points flexural strength of zirconia, and to provide reference for surface microstructure optimization of zirconia implant. METHODS: According to different surface treatment methods, 57 computer aided design/computer aided manufacture (CAD/CAM) zirconia bars (20.0 mm×4.0 mm×1.4 mm) were evenly divided into three groups: sintered group, no treatment after sintering, taken as control; sandblasted group, sandblasted with 110 μm aluminium oxide (Al₂O₃) after sintering; microgrooved group, femtosecond laser fabricated microgrooves with 50 μm width, 30 μm depth, and 100 μm pitch. Surface microscopic topography was observed with scanning electron microscope (SEM) and 3D laser microscope. Further, surface roughness in each group and microgroove size were measured. Crystal phase was analyzed with X-ray diffraction. Specimens were subjected to three- points flexural strength test, and Weibull distribution was used to analyze their strength characteristics. RESULTS: SEM showed that sintered surface was flat with clear grain structure; sandblasted surface exihibited bumps and holes with sharp margins and irregular shape; microgrooves were regularly aligned without evident defect, and nano-scale particles were observed on the surface inside of the microgrooves. Ra value of microgrooved group [(9.42±0.28)] μm was significantly higher than that of sandblasted group [(1.04±0.03) μm] and sintered group [(0.60±0.04) μm], and there was statistical difference between sandblasted group and sintered group (P < 0.001). The microgroove size was precise with (49.75±1.24) μm width, (30.85±1.02) μm depth, and (100.58±1.94) μm pitch. Crystal phase analysis showed that monoclinic volume fraction of sandblasted group (18.17%) was much higher than that of sintered group (1.55%), while microgrooved group (2.21%) was similar with sintered group. The flexural strength of sandblasted group (986.22±163.25) MPa had no statistical difference with that of sintered group (946.46±134.15) MPa (P=0.847), but the strength in microgrooved group (547.92±30.89) MPa dropped significantly compared with the other two groups (P < 0.001). Weibull modulus of sintered, sandblasted, microgrooved groups were 7.89, 6.98, and 23.46, respectively. CONCLUSION Femtosecond laser was able to form micro/nanostructured microgrooves on zirconia surface, which deleteriously affected the flexural strength of zirconia.
Ceramics ; Dental Materials ; Flexural Strength ; Humans ; Lasers ; Materials Testing ; Microscopy, Electron, Scanning ; Surface Properties ; Yttrium ; Zirconium

Liver malignant tumors are one of the most common causes of cancer-related deaths in China. Selective internal yttrium-90 radioembolization therapy ((90)Y-SIRT) is a kind of promising local minimally invasive method, and its effectiveness and safety has been confirmed in clinical application over the past two decades. Moreover, it has been approved by the U.S. National Comprehensive Cancer Network and other international guidelines for the topical treatment of patients with liver malignancies. Taking into account the complexity of the (90)Y-SIRT and the need for multidisciplinary collaboration to improve the safety and success rate of treatment, the Nuclear Medicine Expert Committee of the Chinese society of Clinical Oncology, along with Beijing Nuclear Medicine Quality Control and Improvement Center invited experts from surgical oncology, interventional medicine, nuclear medicine, and other related fields to discuss and form a consensus on the clinical diagnosis, treatment and management, which mainly included definition, indications and contraindications, treatment procedures, postoperative follow-up, adverse reactions and complications, radiation safety management, etc. Herein, we provide the reference guidance to establish (90)Y-SIRT standardized management and treatment system various units for relevant practitioners.
Carcinoma, Hepatocellular/radiotherapy* ; China ; Consensus ; Humans ; Liver Neoplasms/radiotherapy* ; Microspheres ; Yttrium Radioisotopes

OBJECTIVE: To identify an imaging predictor for the assessment of early treatment response to yttrium-90 transarterial radioembolization (TARE) in patients with hepatocellular carcinoma (HCC), using a quantitative assessment of dynamic computed tomography (CT) images. MATERIALS AND METHODS: Dynamic contrast-enhanced CT was obtained pre- and 4 weeks post-TARE in 44 patients (34 men, 10 women; mean age, 60 years) with HCC. Computer software was developed for measuring the percentage increase in the combined delayed-enhancing area and necrotic area (pD + N) and the percentage increase in the necrotic area (pNI) in the tumor-containing segments pre- and post-TARE. Local progression-free survival (PFS) was compared between patient groups using Cox regression and Kaplan-Meier analyses. RESULTS: Post-TARE HCC with pD + N ≥ 35.5% showed significantly longer PFS than those with pD + N < 35.5% (p = 0.001). The local tumor progression hazard ratio was 17.3 (p = 0.009) for pD + N < 35.5% versus pD + N ≥ 35.5% groups. HCCs with a high pNI tended to have longer PFS, although this difference did not reach statistical significance. CONCLUSION: HCCs with a larger pD + N are less likely to develop local progression after TARE.
Carcinoma, Hepatocellular ; Disease-Free Survival ; Female ; Humans ; Male ; Tomography, X-Ray Computed ; Treatment Outcome ; Yttrium Radioisotopes

PURPOSE: The purpose of this study was to evaluate the shear bond strength (SBS) of an indirect resin composite (IRC) to the various resin matrix ceramic (RMC) blocks using different surface treatments. MATERIALS AND METHODS: Ninety-nine cubic RMC specimens consisting of a resin nanoceramic (RNC), a polymer-infiltrated hybrid ceramic (PIHC), and a flexible hybrid ceramic (FHC) were divided randomly into three surface treatment subgroups (n = 11). In the experimental groups, untreated (Cnt), tribochemical silica coating (Tbc), and Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) laser irradiation (Lsr) with 3 W (150 mJ/pulse, 20 Hz for 20 sec.) were used as surface treatments. An indirect composite resin (IRC) was layered with a disc-shape mold (2 × 3 mm) onto the treated-ceramic surfaces and the specimens submitted to thermal cycling (6000 cycles, 5 – 55℃). The SBS test of specimens was performed using a universal testing machine and the specimens were examined with a scanning electron microscope to determine the failure mode. Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tukey HSD test (α=.05). RESULTS: According to the two-way ANOVA, only the surface treatment parameter was statistically significant (P<.05) on the SBS of IRC to RMC. The SBS values of Lsr-applied RMC groups were significantly higher than Cnt groups for each RMC material, (P<.05). Significant differences were also determined between Tbc surface treatment applied and untreated (Cnt) PIHC materials (P=.039). CONCLUSION: For promoting a reliable bond strength during characterization of RMC with IRC, Nd:YAG laser or Tbc surface treatment technique should be used, putting in consideration the microstructure and composition of RMC materials and appropriate parameters for each material.
Aluminum ; Ceramics ; Composite Resins ; Fungi ; Shear Strength ; Silicon Dioxide ; Yttrium

PURPOSE: To investigate the rate of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy in the hydroimplantation intraocular lens (IOL) technique. METHODS: This retrospective study was comprised of 6,192 eyes in 3,790 patients who underwent surgery from January 2013 to September 2017 and then were followed up for at least 1 year. The eyes of these patients were divided into two groups: either viscoimplantation or hydroimplantation. The follow-up examinations were carried out on the 1st day, 4th day, 1st month, and 3 months to 1 year postoperatively. The Nd:YAG capsulotomy rates were evaluated by the different IOL implantation techniques and IOL materials. RESULTS: The mean follow-up duration of the patients was in the viscoimplantation group 14.85 ± 2.43 and 15.05 ± 1.93 months in the hydroimplantation group. The Nd:YAG capsulotomy rate was significantly lower in the hydroimplantation group compared with the viscoimplantation group for the entire hydrophilic IOL model (p < 0.001). In addition, the Nd:YAG rate was lower in the hydroimplantation group that used a hydrophilic IOL than it was in the viscoimplantation group, which used a hydrophobic IOL. CONCLUSIONS: The hydroimplantation technique reduced the Nd:YAG capsulotomy rate.
Aluminum ; Capsule Opacification ; Follow-Up Studies ; Humans ; Lens Implantation, Intraocular ; Lenses, Intraocular ; Posterior Capsulotomy ; Retrospective Studies ; Yttrium

Adolescent ; Ciliary Body ; pathology ; surgery ; Cysts ; surgery ; Glare ; Humans ; Male ; Neodymium ; chemistry ; Yttrium ; chemistry

The concept of theranostics, where individual patient-level biological information is used to choose the optimal therapy for that individual, has become more popular in the modern era of ‘personalised’ medicine. With the growth of theranostics, nuclear medicine as a specialty is uniquely poised to grow along with the ever-increasing number of concepts combining imaging and therapy. This special report summarises the status and growth of Theranostic Nuclear Medicine in Singapore.We will cover our experience with the use of radioiodine, radioiodinated metaiodobenzylguanidine, peptide receptor radionuclide therapy, prostate specific membrane antigen radioligand therapy, radium-223 and yttrium-90 selective internal radiation therapy.We also include a section on our radiopharmacy laboratory, crucial to our implementation of theranostic principles. Radionuclide theranostics has seen tremendous growth and we hope to be able to grow alongside to continue to serve the patients in Singapore and in the region.
Hope ; Humans ; Lutetium ; Membranes ; Nuclear Medicine ; Prostate ; Radium ; Receptors, Peptide ; Singapore ; Theranostic Nanomedicine ; Yttrium

PURPOSE: We report a case of late-onset capsular block syndrome, which resulted in a misdiagnosis of intraocular lens (IOL) opacity. CASE SUMMARY: A 59-year-old man visited our clinic with reduced visual acuity in the right eye from 1 year prior. He had undergone uncomplicated bilateral cataract surgery by phacoemulsification with IOL implants at another hospital 10 years before. There was no specific history with the exception of hypertension. After being diagnosed in the ophthalmology clinic with IOL degeneration and opacity in the right eye, he was referred to our hospital for IOL replacement. Upon examination, his right uncorrected visual acuity was 0.06 and intraocular pressure was 22 mmHg. The refractive error could not be checked due to IOL opacity. Slit-lamp microscopy revealed a cloudy, milky IOL. Anterior-segment optical coherence tomography of the right eye showed retention of a highly reflective material in the lens capsule behind the IOL. Posterior capsule enlargement of the right eye was confirmed on ultrasound biomicroscopy. After neodymium-doped yttrium aluminium garnet (Nd:YAG) laser capsulotomy was performed, the homogeneous space disappeared and the eye recovered normal visual acuity. CONCLUSIONS: Capsular block syndrome is a rare complication that can occur shortly (1 day to 2 days) after cataract surgery. Late-onset capsular block syndrome, which occurs 10 years after surgery differs from typical clinical manifestations. Thus, capsular block syndrome is an important consideration upon the presentation of opacification due to IOL degeneration.
Cataract ; Diagnostic Errors ; Humans ; Hypertension ; Intraocular Pressure ; Lenses, Intraocular ; Microscopy ; Microscopy, Acoustic ; Middle Aged ; Ophthalmology ; Phacoemulsification ; Refractive Errors ; Tomography, Optical Coherence ; Visual Acuity ; Yttrium