Ultrasensitive Photochromic Iodocuprate(I) Hybrid.

By employing in situ methylnicotinohydrazide dication (MNH(2+)) as an electron acceptor, we have constructed an iodocuprate(I) hybrid {[MNH][Cu2I3]2}n (1), which exhibits charge transfer (CT) thermochromism due to the intense absorption of CT and electron transfer (ET) photochromism with high photocoloration contrast and fast response to UV irradiation due to the synergetic effect of valence change of copper ions.

Clinical performance of anterior resin-bonded fixed dental prostheses with different framework designs: A systematic review and meta-analysis.

OBJECTIVES: To systematically review the failure rate and complications of different framework designs of resin-bonded fixed dental prostheses (RBFDPs) in the anterior region. METHODS: A systematic search for clinical studies on RBFDPs published prior to December 2014 in Medline/PubMed, EMBASE, and Cochrane Library databases was conducted and complemented by a manual search. Randomized controlled trials (RCTs) as well as prospective and retrospective cohort studies that compared at least two RBFDP framework designs with a minimum of 2 years follow up were included in this review. The quality of the included studies were assessed using the Newcastle-Ottawa scale for cohort studies and Cochrane Handbook for RCT. Prostheses-based data on reported failure rate/survival rate, debonding, and fractures were analyzed by meta-analysis. RESULTS: Of 1010 screened articles, one RCT and 4 cohort studies fit the inclusion criteria and were included in the meta-analysis. All included articles have a high risk of bias. Failure rates of single-retainer cantilever RBFDPs were lower than two-retainer fixed-fixed RBFDPs (OR 0.42, 95% CI 0.19-0.94, P=0.04). Metal-ceramic RBFDPs showed no difference of failure rates between cantilever RBFDPs and two-retainer fixed-fixed RBFDPs (OR 0.93, 95% CI 0.33-2.63, P=0.89). Debonding was not significantly different between cantilever RBFDPs and two-retainer fixed-fixed RBFDPs (OR 0.61, 95% CI 0.23-1.60, P=0.32). Metal-ceramic RBFDPs showed no difference of debonding between cantilever RBFDPs and two-retainer fixed-fixed RBFDPs (OR 0.81, 95% CI 0.28-2.34, P=0.70,). CONCLUSIONS: Within the limitations of the present study, cantilever RBFDPs demonstrate lower clinical failure than two-retainer RBFDPs in the anterior region. The failure of metal-ceramic RBFDPs is independent of the framework design, while the failure of all-ceramic RBFDPs with different designs has not been clear yet. CLINICAL SIGNIFICANCE: Based on the principle of minimally invasive treatment, less number of retainers is recommended for RBFDPs.

Topology adaptive vessel network skeleton extraction with novel medialness measuring function.

Vessel tree skeleton extraction is widely applied in vascular structure segmentation, however, conventional approaches often suffer from the adjacent interferences and poor topological adaptability. To avoid these problems, a robust, topology adaptive tree-like structure skeleton extraction framework is proposed in this paper. Specifically, to avoid the adjacent interferences, a local message passing procedure called Gaussian affinity voting (GAV) is proposed to realize adaptive scale-growing of vessel voxels. Then the medialness measuring function (MMF) based on GAV, namely GAV-MMF, is constructed to extract medialness patterns robustly. In order to improve topological adaptability, a level-set graph embedded with GAV-MMF is employed to build initial curve skeletons without any user interaction. Furthermore, the GAV-MMF is embedded in stretching open active contours (SOAC) to drive the initial curves to the expected location, maintaining smoothness and continuity. In addition, to provide an accurate and smooth final skeleton tree topology, topological checks and skeleton network reconfiguration is proposed. The continuity and scalability of this method is validated experimentally on synthetic and clinical images for multi-scale vessels. Experimental results show that the proposed method achieves acceptable topological adaptability for skeleton extraction of vessel trees.

[Investigation on relationship between wedge-shaped defects and occlusal interference].

OBJECTIVE: To investigate the relationship between wedge-shaped defects and occlusal interference. METHODS: Following examination from 46 patients, a total of 157 teeth were identified to have the criteria set for wedge-shaped defects and regarded as the experiment group. Also, 157 adjacent teeth exhibiting no such noncarious cervical lesions were randomly selected from the same group of patients and regarded as the control group. The distribution of occlusal force and time were examined with T-Scan II system in 46 patients with wedge-shaped defects in intercuspal occlusion position, protrusive movement and lateral movement. Occlusal interference and premature contact were evaluated and compared between the two groups. RESULTS: The proportion of the teeth with premature contact in experiment group was 6.37%, while the control group was 2.55%, there was no significant difference between the two groups (P > 0.05). The total proportion with occlusal interferences in experiment group was 23.57%, which was significantly higher than that of the control group (10.19%, P < 0.05), in experiment group the proportion with working side interferences was 15.92%, and in control group, the proportion was 3.82%, there was significant difference between the two groups (P < 0.01). At the same time, the teeth with occlusal interferences had more serious degree of the wedge-shape defects than those with no occlusal interference. CONCLUSION: The increased occlusal force has relation to the formation as well as severity of wedge-shaped defects.

[Effect of zirconia content on flexural strength and fracture toughness of dental zirconia toughened composite alumina ceramic].

OBJECTIVE: To evaluate mechanical properties of zirconia toughened composite alumina (ZTCA) ceramic used for dental application, characterize the effect of different zirconia contents on mechanical properties of ZTCA. METHODS: Dental alumina ceramic powder was prepared by sol-gel method, and four groups of ZTCA powders with different zirconia contents were prepared via surface-induced precipitation method. All five groups of powders were dry-pressed and then sintered to make standard specimens for mechanical tests. The flexural strength and fracture toughness of these specimens were evaluated, and the fractography was characterized by scanning electronic microscope (SEM). Phases of ZTCA were also determined using X-ray diffraction (XRD). RESULTS: It was found that the flexural strength of ZTCA ceramics increases with ZrO2 content up to 30%, and decreases thereafter. ZTCA specimens containing 30% ZrO2 show the highest flexural strength, and the corresponding fracture toughness was 1.85 MPa x m(1/2). The XRD results of ZTCA ceramics showed the phase constituents of alpha-Al2O3, t-ZrO2 and a small amount of m-ZrO2. CONCLUSION: The strengthening and toughening mechanisms of ZTCA depend on ZrO2 content. In the range of 15%-30% ZrO2, the stress-induced phase transformation toughening mechanism is dominant, while microcrack and deflection exist as the additional toughening mechanism when ZrO2 addition amount is above 30%.