Disposal of drilling waste in salt mines in China.

A lot of drilling wastes are produced during oil/gas exploration and exploitation in China. Many countries have built and successfully run projects to dispose of wastes in salt mines, which fully demonstrates the feasibility and superiority of this technology. The application prospects of using salt mines to dispose of drilling wastes is comprehensively evaluated from many aspects. It is concluded that this technology has broad application prospects in China. The scientific and technical problems that need to be solved in order to successfully use this technology are systematically summarized, and some practical suggestions are put forward to improve relevant laws and policies. Considering the geological conditions of salt mines and the requirements of laws and regulations in China, a set of perfect and more advanced Chinese schemes has been proposed.

Direct resin composite restoration of maxillary central incisors using a 3D-printed template: two clinical cases.

BACKGROUND: Three-dimensional (3D) printing technology is used widely in dentistry for applications including implant surgery, oral and maxillofacial surgery, orthognathic surgery, endodontics and prosthodontics. Using a 3D-printed template makes performing the repair procedure faster and more convenient. The aesthetic restoration of anterior teeth can recover facial beauty, enhance speaking and chewing functions and improve the quality of life of the patient. CASE PRESENTATION: This article describes two kinds of clinical cases including fractured teeth and dental caries. In both, a 3D-printed template was used for direct resin composite restoration of maxillary central incisors. A 3D-printed template was built using the following 3-step process: data acquisition was conducted via intra-oral scanning, virtual modeling was performed using an imaging process, and manufacturing was performed using a 3D printer. Aesthetically restoring the maxillary incisors with the assistance of the 3D-printed template achieved the anticipated results, and the patients were very satisfied with the effect. CONCLUSIONS: The direct resin composite restoration of maxillary central incisors using a 3D-printed template represents a rapid, convenient, aesthetic and functional option for treating maxillary central incisors. A 3D-printed template is therefore an acceptable and reliable alternative to traditional direct composite restoration of maxillary central incisors including fractured teeth and dental caries.

Mathematical model of salt cavern leaching for gas storage in high-insoluble salt formations.

A mathematical model is established to predict the salt cavern development during leaching in high-insoluble salt formations. The salt-brine mass transfer rate is introduced, and the effects of the insoluble sediments on the development of the cavern are included. Considering the salt mass conservation in the cavern, the couple equations of the cavern shape, brine concentration and brine velocity are derived. According to the falling and accumulating rules of the insoluble particles, the governing equations of the insoluble sediments are deduced. A computer program using VC++ language is developed to obtain the numerical solution of these equations. To verify the proposed model, the leaching processes of two salt caverns of Jintan underground gas storage are simulated by the program, using the actual geological and technological parameters. The same simulation is performed by the current mainstream leaching software in China. The simulation results of the two programs are compared with the available field data. It shows that the proposed software is more accurate on the shape prediction of the cavern bottom and roof, which demonstrates the reliability and applicability of the model.

Novel navigation technique for the endodontic treatment of a molar with pulp canal calcification and apical pathology.

Apical periodontitis, the inflammation of periapical tissue, commonly requires root canal treatment to achieve apical healing. However, if it is accompanied by pulp canal calcification, the treatment becomes complicated, and locating the root canal can be challenging. This case report describes a novel approach for treating a molar with pulp canal calcification and apical pathology. Due to the risk of perforation during treatment, a digitally printed template was used to assist in accurately locating the root canal. After six months, the patient was asymptomatic and the periradicular radiolucency was gradually reducing in size.

Effect of different dental burs for experimental induction of pulpitis in mice.

OBJECTIVE: To evaluate the effect of using different dental burs on the development of pulpal inflammation after pulpal exposure in mice. DESIGN: Eighty-eight C57BL/6 mice were randomly assigned to group A (n=40), group B (n=40) and control group (n=8). The pulps of the maxillary first molars were occlusally exposed using » round burs and polishing burs in group A and B respectively. Animals were sacrificed randomly at 0h, 4h, 8h, 12h and 24h after pulpal exposure. Micro-CT scanning was used to determine the success rate of sample preparation. Pulpal tissue changes were evaluated by histopathologic and immunohistochemical analyses. RESULTS: The success rates of sample preparations were 85% in group A and 90% in group B. The mean maximum diameter of pulpal exposure area was 625.6±30.6µm in group A and 402.7±18.0µm in group B (p<0.05). In addition, the mean of the minimum remaining dentine thickness at the marked region of interest was 133.2±29.9µm in group A and 261.4±16.3µm in group B (p<0.05). Histopathologic staining demonstrated more signs of inflammation in both groups, as the duration of pulpal exposure increases. However, the rate of inflammatory progress was higher in group A, even spreading to the root pulp tissue within a few hours. For group B, the progress was relatively slow. CONCLUSIONS: Pulpal exposure with different sizes of dental burs affects changes in the development of pulpal inflammation in mice.