Three-dimensional inlay-guided endodontics applied in variant root canals: A case report and review of literature

BACKGROUND Root canal retreatment is common after root canal therapy in clinical situations.Especially,completing the retreatment of variant root canals can be challenging.This is particularly true for the molars located at the end of the dental arch.However,advancements in digital dental diagnosis and treatment techniques can solve these problems.Here,we describe a case of a maxillary second molar with a variant distobuccal root canal treated via a novel“inlay-guided endodontics”technique based on improved computer-generated programs.CASE SUMMARY A 63-year-old man complained of a defect in the maxillary left second molar.The tooth,diagnosed with post-treatment endodontic disease,was initially treated by conventional methods,which were ineffective.Our“inlay-guided endodontics”technique was subsequently adopted,with the establishment of a precise integrated three-dimensional(3D)plate model of cone-beam computed tomography data and a digital impression of the dentition.An optimal root canal approach was generated for the“virtual file”in the 3D model.The plate data were imported into a 3D printer and printed.With the help of the guide plate,the file was accurately placed into the cervical third of the distal root canal.The root canal and prosthodontic treatments successfully proceeded subsequently.CONCLUSION Our newly developed inlay guide plates may facilitate individualized and minimally invasive root canal treatment.

Processing Mechanism of Chinese Verbal Jokes:Evidence from ERP and Neural Oscillations

The cognitive processing mechanism of humor refers to how the system of neural circuitry and pathways in the brain deals with the incongruity in a humorous manner. The past research has revealed different stages and corresponding functional brain activities involved in humor-processing in terms of time and space dimensions, highlighting the effects of the time windows of about 400 ms, 600 ms, and 900 ms. However, much less is known about humor processing in light of the frequency dimension. A total of 36 Chinese participants were recruited in this experiment, with Chinese jokes, nonjokes, and nonsensical sentences used as the stimuli. The experimental results showed that there were significant differences among conditions in the P200 effect, which signified that the incongruity detection had already been integrated and perceived at about 200 ms, prior to the semantic integration at about 400 ms. This pre-processing is specific to Chinese verbal jokes due to the simultaneous involvement of both orthographic and phonologic parts in processing Chinese characters. The analysis on the frequency dimension indicated that beta’s power particularly reflected the characteristics of different stages in Chinese verbal humor processing. Jokes’ and nonsensical sentences’ relative power changes on the beta band ranked significantly higher than that of nonjokes at about 200 ms, which suggested the existence of more difficulties in meaning construction in pre-processing the incongruities. This indicated a continuity between the analysis of event related potential (ERP) components and neural oscillations and revealed the key role of the beta frequency band in Chinese verbal joke processing.

An ERP Study of the Object Preference in Processing Chinese Relative Clauses

Through an event-related potential（ERP）study, we examined the processing mechanisms of four types of Chinese（Mandarin） relative clauses（RCs）,namely subject subject-extracted relative clause（SSR）,subject object-extracted relative clause（SOR）, object subject-extracted relative clause（OSR）, and object object-extracted relative clause（OOR） to test the universality and language specificity of RC comprehension processes. The results of this study support a preference for object-extracted RCs modifying both the subject and object of a sentence, i.e.,SORs and OORs. In particular, ERP results showed stronger P600 effects in the RC region for SSRs compared with SORs, which we argue reflects a canonical word order theory. Stronger N400 effects were observed for verbs compared with nouns, reflecting easier understanding for nouns. ERP results from the matrix clause object and the relativizer “de” showed stronger P600 effects in SSRs compared with SORs,suggesting thematic structure effects on syntactic construction and the processing preference of the whole sentence.

Epitaxial growth of highly strained antimonene on Ag（111）

The synthesis of antimonene, which is a promising group-V 2D material for both fundamental studies and technological applications, remains highly challenging. Thus far, it has been synthesized only by exfoliation or growth on a few substrates. In this study, we show that thin layers of antimonene can be grown on Ag（111） by molecular beam epitaxy. High-resolution scanning tunneling microscopy combined with theoretical calculations revealed that the submonolayer Sb deposited on a Ag（111） surface forms a layer of AgSb2 surface alloy upon annealing. Further deposition of Sb on the AgSb2 surface alloy causes an epitaxial layer of Sb to form, which is identified as antimonene with a buckled honeycomb structure. More interestingly, the lattice constant of the epitaxial antimonene （5 /-） is much larger than that of freestanding antimonene, indicating a high tensile strain of more than 20%. This kind of large strain is expected to make the antimonene a highly promising candidate for room- temperature quantum spin Hall material.

Dissociation of liquid water on defective rutile TiO2 （110） surfaces using ab initio molecular dynamics simulations

In order to obtain a comprehensive understanding of both thermodynamics and kinetics of water dissociation on TiO2, the reactions between liquid water and perfect and defective rutile TiO2 （110） surfaces were investigated using ab initio molecular dynamics simulations. The results showed that the free-energy barrier （-4.4 kcal/mol） is too high for a spontaneous dissociation of water on the perfect rutile （110） surface at a low temperature. The most stable oxygen vacancy （VOl） on the rutile （110） surface cannot promote the dissociation of water, while other unstable oxygen vacancies can significantly enhance the water dissociation rate. This is opposite to the general understanding that Vol defects are active sites for water dissociation. Furthermore, we reveal that water dissociation is an exothermic reaction, which demonstrates that the dissociated state of the adsorbed water is thermodynamically favorable for both perfect and defective futile （110） surfaces. The dissociation adsorption of water can also increase the hydrophilicity of TiO2.

Computational study on the half-metallicity in transition metal-oxide-incorporated 2D g-C3N4 nanosheets

In this study, based on the first-principles calculations, we systematically investigated the electronic and magnetic properties of the transition metal-oxide-incorporated 2D g-C3N4 nanosheet （labeled C3N4- TM-O, TM - Sc-Mn）. The results suggest that the TM-O binds to g-CaN4 nanosheets strongly for all systems. We found that the 2D C3N4-TM-O framework is ferromagnetic for TM = Sc, Ti, V, Cr, while it is antiferromagnetic for TM = Mn. All the ferromagnetic systems exhibit the half-metallic property. Furthermore, Monte Carlo simulations based on the Heisenberg model suggest that the Curie temperatures （To） of the CaN4-TM-O （TM --- Sc, Ti, V, Cr） framework are 169 K, 68 K, 203 K, and 190 K, respectively. Based on Bader charge analysis, we found that the origin of the half-metallicity at Fermi energy can be partially attributed to the transfer of electrons from TM atoms to the g-C3N4 nanosheet. In addition, we found that not only electrons but also holes can induce half-metallicity for 2D g-C3N4 nanosheets, which may help to understand the origin of half-metallicity for graphitic carbon nitride.