In Situ Regeneration of Silicon Microring Biosensors Coated with Parylene C.

Optical biosensors support disease diagnostic applications, offering high accuracy and sensitivity due to label-free detection and their optical resonance enhancement. However, optical biosensors based on noble metal nanoparticles and precise micro-electromechanical system technology are costly, which is an obstacle for their applications. Here, we proposed a biosensor reuse method with nanoscale parylene C film, taking the silicon-on-insulator microring resonator biosensor as an example. Parylene C can efficiently adsorb antibody by one-step modification without any surface treatment, which simplifies the antibody modification process of sensors. Parylene C (20 nm thick) was successfully coated on the surface of the microring to modify anti-carcinoembryonic antigen (anti-CEA) and specifically detect CEA. After sensing, parylene C was successfully removed without damaging the sensing surface for the sensor reusing. The experimental results demonstrate that the sensing response did not change significantly after the sensor was reused more than five times, which verifies the repeatability and reliability of the reusable method by using parylene C. This framework can potentially reduce the cost of biosensors and promote their further applications.

Recent advances and applications of molecularly imprinted polymers in solid-phase extraction for real sample analysis.

Sample pretreatment is essential for the analysis of complicated real samples due to their complex matrices and low analyte concentrations. Among all sample pretreatment methods, solid-phase extraction is arguably the most frequently used one. However, the majority of available solid-phase extraction adsorbents suffer from limited selectivity. Molecularly imprinted polymers are a type of tailor-made artificial antibodies and receptors with specific recognition sites for target molecules. Using molecularly imprinted polymers instead of conventional adsorbents can greatly improve the selectivity of solid-phase extraction, and therefore molecularly imprinted polymer-based solid-phase extraction has been widely applied to separation, clean up and/or preconcentration of target analytes in various kinds of real samples. In this article, after a brief introduction, the recent developments and applications of molecularly imprinted polymer-based solid-phase extraction for determination of different analytes in complicated real samples during the 2015-2020 are reviewed systematically, including the solid-phase extraction modes, molecularly imprinted adsorbent types and their preparations, and the practical applications of solid-phase extraction to various real samples (environmental, food, biological, and pharmaceutical samples). Finally, the challenges and opportunities of using molecularly imprinted polymer-based solid-phase extraction for real sample analysis are discussed.

Er:YAG laser settings for debonding zirconia restorations: An in vitro study.

This in vitro study aimed to determine the optimal frequency and energy settings for debonding zirconia restorations using an erbium-doped yttrium aluminum garnet (Er:YAG) laser. A total of 200 zirconia specimens (5 mm × 5 mm × 1.5 mm) were fabricated from two types of materials: (1) 3 mol% yttria oxide stabilized tetragonal zirconia polycrystalline (3Y-TZP) and (2) 5 mol% yttria oxide stabilized tetragonal zirconia polycrystalline (5Y-TZP). The zirconia specimens were bonded to dentin using resin cement (RelyX Ultimate, 3 M) and divided into 20 groups based on their laser treatments (n = 5). Er:YAG laser treatment was applied at various frequencies (10 Hz and 20 Hz) and energies (80 mJ, 100 mJ, 120 mJ, 140 mJ, 160 mJ, 180 mJ, 200 mJ, 220 mJ, 240 mJ, and 260 mJ). The time required to debond the specimens and the temperature changes that dentin underwent during the laser treatment were recorded. The surface morphologies of the debonded dentin and zirconia specimens were observed using scanning electron microscopy (SEM). Additional zirconia specimens were fabricated for 4-point flexural strength testing and surface roughness measurements. Statistical analyses were conducted using three-way analysis of variance (ANOVA) and Student-Newman-Keuls (SNK)-q tests (α = 0.05). The debonding time of each specimen varied between 4.8 and 160.4 s, with an average value of 59.2 s. The dentin temperature change for each specimen ranged from 2.3 to 3.6 °C, with an average value of 2.7 °C. The debonding time was significantly influenced by the zirconia material type and laser energy, but it was not affected by the laser frequency. Among the specimens, those made of 3Y-TZP needed significantly more time for debonding than 5Y-TZP. The optimal energies were 220 mJ for 3Y-TZP and 200 mJ for 5Y-TZP. The laser frequency, laser energy, and type of zirconia material had no effect on the dentin temperature change. Additionally, no surface alternations were observed on the dentin or zirconia materials after laser treatment. The surface roughness and flexural strength of the zirconia materials remained unchanged after laser treatment. In summary, Er:YAG laser treatment effectively and safely removes zirconia restorations without impacting their mechanical properties, with a safe temperature change of less than 5.6 °C. The optimum frequency and energy settings for debonding 3Y-TZP and 5Y-TZP restorations were found to be 10/20 Hz and 220 mJ and 10/20 Hz and 200 mJ, respectively.

Repolishing in situ eroded CAD/CAM restorative materials and human enamel.

This study aimed to evaluate the effects of repolishing on the surface microhardness (SMH), color change (ΔE), and translucency parameter (TP) of previously in situ eroded computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials and human enamel. Each of 8 volunteers wore an intraoral appliance containing 3 CAD/CAM restorative material specimens (IPS e.max CAD lithium disilicate ceramic, Lava Ultimate hybrid ceramic, and poly (methyl methacrylate) (PMMA) block) and 1 human enamel specimen. The specimens were subjected to in situ erosion cycles by rinsing with a cola drink (4 × 5 min/day) for 14 days. After erosion, the specimens were polished with a silicone polishing system (Ceramister, Shofu Inc, Kyoto, Japan). The SMH and color of the specimens were determined at baseline (T1), after erosion (T2), and after repolishing (T3). The ΔE and TP values of the specimens were further calculated. The data were statistically analyzed using repeated-measures analysis of variance (ANOVA) and Bonferroni's test (α = 0.05). After erosion, a decrease in the SMH of the restorative materials and enamel was observed (all P < 0.001), and a decrease in the TP of the enamel was observed (P = 0.016). The ΔE values of the enamel (ΔE = 7.32) and Lava Ultimate (ΔE = 3.19) exceeded the clinically unacceptable threshold after erosion. After repolishing, the SMH of the restorative materials and enamel at T3 was significantly higher than that at T2 (all P < 0.001). No significant difference was found in the TP and ΔE values of the restorative materials and enamel between T2 and T3. In conclusion, erosion negatively affected the surface properties and appearance of the CAD/CAM restorative materials and human enamel. Repolishing contributed to restoring the compromised SMH of the eroded restorative materials and enamel to a certain extent. However, repolishing did not restore the color of the eroded restorative materials and enamel.

[Effect of modified root directional flap applied for implant surgery in the secondary implantation of maxillary posterior teeth].

PURPOSE: To explore the reconstruction method of buccal keratinized gingiva around implant in posterior maxillary area, and to evaluate its clinical effects and periodontal condition around the implants. METHODS: A total of 11 implants were selected by screening from 11 patients who had inadequate keratinized gingiva and needed to undergo secondary operation. An optimized root directional flap technique was applied to reconstruct keratinized gingiva in the stage of secondary operation. Crown restoration was finished 6 weeks after surgery and the patients were recalled 3 months after dental restoration. Effective keratinized mucosal width was recorded separately before the operation, crown restoration and 3 months after restoration. Clinical periodontal examination was conducted 3 months after restoration including probing depth (PD), bleeding on probing (BOP) and periapical film. SPSS19.0 software package was used for paired t test. RESULTS: The average keratinized mucosal width was (1.44±0.34) mm and (3.30±0.36) mm before operation and after crown restoration, respectively.There was an average increase of 1.86 mm in effective keratinized mucosal width compared with preoperative value (P<0.05). Three months after restoration, the newly health keratinized gingiva remained stable without obvious inflammation. The mean width was (3.34±0.33) mm (P=0.58). Clinical periodontal examinations showed a mean PD of 2.83±1.20 and the mean BOP of 18.2%. CONCLUSIONS: By using modified root directional flap technique in the secondary implant operation, the buccal keratinized gingiva around the implants can be effectively reconstructed. The short-term outcomes are satisfactory.

Soft tissue release combined with joint-sparing osteotomy for treatment of cavovarus foot deformity in older children: Analysis of 21 cases.

BACKGROUND: Cavovarus foot is a common form of foot deformity in children, which is clinically characterized by an abnormal increase of the longitudinal arch of the foot, and it can be simultaneously complicated with forefoot pronation and varus, rearfoot varus, Achilles tendon contracture, or cock-up toe deformity. Muscle force imbalance is the primary cause of such deformity. Many diseases can lead to muscle force imbalance, such as tethered cord syndrome, cerebral palsy, Charcot-Marie-Tooth disease, and trauma. At present, many surgical treatments are available for cavovarus foot. For older children, priority should be given to midfoot osteotomy and fusion. Since complications such as abnormal foot length, foot stiffness, and abnormal gait tend to develop postoperatively, it is important to preserve the joints and correct the deformity as much as possible. Adequate soft tissue release and muscle balance are the keys to correcting the deformity and avoiding its postoperative recurrence. AIM: To assess the efficacy of soft tissue release combined with joint-sparing osteotomy in the treatment of cavovarus foot deformity in older children. METHODS: The clinical data of 21 older children with cavovarus foot deformity (28 feet) who were treated surgically at the Ninth Department of Orthopedics of Jizhong Energy Xingtai Mining Group General Hospital from November 2014 to July 2017 were retrospectively analyzed. The patients ranged in age from 10 to 14 years old, with an average age of 12.46 ± 1.20 years. Their main clinical manifestations were deformity, pain, and gait abnormality. The patients underwent magnetic resonance imaging of the lumbar spine, electromyographic examination, weight-bearing anteroposterior and lateral X-rays of the feet, and the Coleman block test. Surgical procedures including metatarsal fascia release, Achilles tendon or medial gastrocnemius lengthening, "V"-shaped osteotomy on the dorsal side of the metatarsal base, opening medial cuneiform wedge osteotomy, closing cuboid osteotomy, anterior transfer of the posterior tibial tendon, peroneus longus-to-brevis transfer, and calcaneal sliding osteotomy to correct hindfoot varus deformity were performed. After surgery, long leg plaster casts were applied, the plaster casts were removed 6 wk later, Kirschner wires were removed, and functional exercise was initiated. The patients began weight-bearing walk 3 mo after surgery. Therapeutic effects were evaluated using the Wicart grading system, and Meary's angles and Hibbs' angles were measured based on X-ray images obtained preoperatively and at last follow-up to assess their changes. RESULTS: The patients were followed for 6 to 32 mo, with an average follow-up period of 17.68 ± 6.290 mo. Bone healing at the osteotomy site was achieved at 3 mo in all cases. According to the Wicart grading system, very good results were achieved in 18 feet, good in 7, and fair in 3, with a very good/good rate of 89.3%. At last follow-up, mean Meary's angle was 6.36° ± 1.810°, and mean Hibbs' angle was 160.21° ± 4.167°, both of which were significantly improved compared with preoperative values (24.11° ± 2.948° and 135.86° ± 5.345°, respectively; P < 0.001 for both). No complications such as infection, skin necrosis, or bone nonunion occurred. CONCLUSION: Soft tissue release combined with joint-sparing osteotomy has appreciated efficacy in the treatment of cavovarus foot deformity in older children.

Determination of the content of alkyl ketene dimer in its latex by an ionic-liquid assisted headspace gas chromatography.

This paper reports on an ionic-liquid assisted headspace gas chromatographic (HS-GC) for the determination of the content of alkyl ketene dimer (AKD) in its latex samples, in which the GC system was equipped with a thermal conductivity detector (TCD). The method was based on the AKD hydrolysis conducted in 1-butyl-3-methylimidazolium chloride (ionic-liquid) added medium at 100°C for 10min in a closed headspace sample vial, and the measured CO2 (the resulting product of the hydrolysis) by HS-GC. The results showed that the present method has a good measurement precision (RSD <2.3%) and accuracy (recoveries from 96 - 105%), and the limit of quantitation (LOQ) is 0.9%. The present method is very suitable to be used for the routine check of AKD content in its latex sample in mill applications. The study also showed that the content of AKD in the tested commercial latex samples were in the range of 3.5-12%.

Proper selection of contemporary dental cements.

Today proper selection of dental cements is a key factor to achieve a successful restoration and will greatly increase the chances of long-term success of the restoration. In recent years, many newly formulated dental cements have been developed with the claim of better performance compared to the traditional materials. Unfortunately, selection of suitable dental cement for a specific clinical application has become increasingly complicated, even for the most experienced dentists. The purpose of this article is to review the currently existing dental cements and to help the dentists choose the most suitable materials for clinical applications.

[The relationship between dietary factors and susceptibility of periodontal disease].

PURPOSE: A clinical survey was made on the life style and dietary behaviors of people with non-periodontal disease and people with periodontal disease for prevention and treatment of periodontal diseases. METHODS: 72-hour diet analysis and frequency analysis of dietary intake were performed in 60 patients with moderate-to-severe periodontal disease and 60 patients with healthy periodontal tissues randomly selected in the Ninth People's Hospital for dental treatment. The data was analyzed by Student's t test and Chi-square test with SPSS13.0 software package. RESULTS: There was significant difference (P<0.05) in vitamin C, flavonoids and ß-carotene dietary intake between control group and periodontal disease group; In periodontal disease group, dietary intake of selenium and zinc intake was different from the normal control, but the difference was not statistically significant (P>0.05). CONCLUSIONS: There is a close relationship between oral health and antioxidant nutrients. Lower dietary vitamin C content, flavonoid content and ß-carotene intake lead to destruction of periodontal tissue and higher incidence of periodontal disease.

[Study of the relative factors of the biological behavior of pleomorphic adenoma in parotid].

OBJECTIVE: To study the growth way of parotid pleomorphic adenoma and the relative factors. METHODS: The histological slides of 97 cases of the primary parotid pleomorphic adenoma were examined for the state of intra-capsule infiltration and extra-infiltration. The relative relationships between the infiltration state and the histological type, relative amount of various components, size and course of the tumor were analysed to investigate the growth way and relative factors. RESULTS: 1. There were more chances to develop infiltration of tumor in which the major content was epithelium. The tumor was severer with the increasing of epithelium, and decreasing of mucous content and elongation of course of the disease. 2. The limitation of the extra-envelop infiltration and budding was 0.085 - 0.210 mm, so, the boundary of partial parotidectomy should be away from the 1 cm envelop. CONCLUSION: The growth way of parotid pleomorphic adenoma is related to the histological types and characters, relative amount of various components and the course of the tumor.