[Effects of the blended nitrogen fertilizers combined with inhibitors on soil nitrogen pools.] / æŽºæ··æ°®è‚¥é æ–½æŠ‘åˆ¶å‰‚å¯¹åœŸå£¤æ°®åº“çš„è°ƒæŽ§ä½œç”¨.

Pot experiment with winter wheat was conducted to investigate the effects of blended nitrogen (N) fertilizer (slow-release fertilizer-N:urea-N=1:1) combined with N fertilizer inhibitor NAM on soil ammonium (NH4+-N), nitrate (NO3--N), microbial biomass nitrogen (MBN) and fixed-ammonium (FN) contents. We analyzed dynamic characteristics of soil mineral N, MBN, FN pools under different treatments. There were six treatments, including no N fertilizer (CK), conventional urea (U), blended N fertilizer (MU), MU plus 2.5‰ NAM (MUN1), MU plus 5‰ NAM (MUN2), and MU plus 7.5‰ NAM (MUN3). Our results showed that, compared to that of MU treatment, MUN2 and MUN3 delayed the appearance time of NH4+-N peak. Averaged across the whole wheat growing period, soil mineral N content for NAM treatments decreased by 5.3%-11.7%. From tillering to maturity stage, MBN mineralization and mineralization rates were 38.96 mg·kg-1 and 91.5%, which was higher than that of U treatment; MBN mineralization and mineralization rates for MUN1, MUN2 and MUN3 treatments were 58.73 mg·kg-1, 83.3%, 94.20 mg·kg-1, 94.6%, 104.46 mg·kg-1 and 96.3%, respectively. The FA mineralization release for NAM treatments were higher by 2.83-9.19 mg·kg-1 than that of MU treatment. The results of path analysis showed that NAM addition weakened the direct effect of soil NH4+-N pool on NO3--N pool but enhanced the indirect effects of FN pool on NO3--N pool through affecting NH4+-N pool. The wheat grain yields of the MUN1, MUN2 and MUN3 treatments were significantly higher by 31.6%, 21.5% and 22.9% than that of MU treatment. Nitrogen use efficiencies were increased by 8.1%, 13.5% and 3.1%, respectively. In summary, through double regulation for N release and transformation in soil, NAM delayed the appearance time of soil NH4+-N peak and retarded its transformation into NO3--N, and increased the roles of MBN and FN in supplying N, thereby increased crop yield and N-fertilizer use efficiency.

Lnc-NTF3-5 promotes osteogenic differentiation of maxillary sinus membrane stem cells via sponging miR-93-3p.

BACKGROUND: The function and the mechanism of long non-coding RNAs (lncRNAs) on the osteogenic differentiation of maxillary sinus membrane stem cells (MSMSCs) remain largely unknown. MATERIALS AND METHODS: The expression of lnc-NTF3-5 and Runt-related transcription factor 2 (RUNX2), Osterix (OSX), and Alkaline Phosphatase (ALP) was examined by quantitative real-time PCR (qRT-PCR) in MSMSCs during the process osteogenic differentiation. Then the function of lnc-NTF3-5 was evaluated by loss- and gain-of-function techniques, as well as qRT-PCR, western blot, and Alizarin Red staining. In addition, the microRNAs (miRNAs) sponge potential of lnc-NTF3-5 was assessed through RNA immunoprecipitation, dual luciferase reporter assay, and in vivo ectopic bone formation. RESULTS: Lnc-NTF3-5, RUNX2, OSX, and ALP increased alone with the differentiation. Inhibition of lnc-NTF3-5 decreased the expression of RUNX2, OSX, and ALP both at mRNA and protein levels. Alizarin red staining showed similar trend. In contrast, overexpression of lnc-NTF3-5 presented totally opposite effects. Besides, overexpression of lnc-NTF3-5 could decrease the expression of microRNA-93-3p (miR-93-3p). Enhance miR-93-3p could also inhibit the expression level of lnc-NTF3-5. RNA immunoprecipitation demonstrated that lnc-NTF3-5 is directly bound to miR-93-3p and dual luciferase reporter assay proved that miR-93-3p targets 3' UTR of RUNX2 to regulate its expression. Ultimately, in vivo bone formation study showed that lnc-NTF3-5 and miR-93-3p inhibitor co-transfection group displayed the strongest bone formation. CONCLUSIONS: The novel pathway lnc-NTF3-5/miR-93-3p/RUNX2 could regulate osteogenic differentiation of MSMSCs and might serve as a therapeutic target for bone regeneration in the posterior maxilla.

The application of functional magnetic resonance imaging technology in oral function research / 口腔疾病防治

@#Functional magnetic resonance imaging is a new magnetic resonance imaging inspection method, which can reflect the imageological change of cerebral cortex when human body is doing various functional movements. The functional movements of the oral cavity such as chewing, gustation, swallowing which is closely related to the changes in the cerebral cortex. Recent years, scholars home and abroad had done many oral researches by fMRI. The results of these studies have great guiding significance to the clinical work and research. It indicates that we can explore more clinical diseases through fMRI technology. This article summarizes the application of fMRI in oral functional research.

Treatment of alveolar cleft with distraction osteogenesis using anchorage with a tooth-microimplant joint in a dog model.

Our aim was to investigate the efficacy of correction of an alveolar cleft with distraction osteogenesis using anchorage with a tooth-microimplant joint in a canine model, which was established in 12 adult mongrel dogs that were subsequently randomised into two groups (n=6 in each). The first group comprised dogs that had osteogenesis using anchorage with a tooth (tooth group), while in the second, anchorage with tooth-microimplant joint (microimplant group) was used. All animals were killed one month after completion of distraction. Samples were collected for gross observation and histological examination. There was a significant difference in the degree of movement of the anchorage teeth in the transport discs between the 2 groups (p<0.01). There was less prominent inclination and shift of the natural teeth in the transport disc and less bony resorption around the root in the microimplant group than in the tooth group. These changes were less remarkable in the microimplant group. Treatment of alveolar cleft by distraction osteogenesis using anchorage with a tooth-microimplant joint is practical, and yields better results.

Guided bone regeneration using collagen membranes for sinus augmentation.

We investigated the effect of guided bony regeneration using collagen membranes for sinus augmentation in the first maxillary molars of 18 adult female beagle dogs. The teeth were extracted bilaterally and the sinus floors were lifted with simultaneous implantation. The grafted material composed of a combination of autografts and Bio-oss in a 2:1 ratio. On the experimental side in each dog, collagen membrane was folded at the lateral osteotomy window, at the apex of the implants, and at a certain part of the palatal bone. On the opposite (control) side, the collagen membrane covered the osteotomy window. Six animals were killed at each of 4, 12, and 24 weeks postoperatively. Gross observation, biomechanical testing, and histological examinations were made. On the experimental side, grafted materials showed no obvious resorption or subsidence, and a new bone had formed at the apex of the implants. On the control side, the grafted materials had been shifted and absorbed. Histological examination showed increased formation of a new bone in the experimental group, which matured over time. At 4 weeks, inflammatory cells were present in the control group, which showed less maturation of the new bone. The pull-out force increased with time and, at week 24, there was a significant difference in pull-out force between the two groups (p<0.01). Guided bony regeneration with the enfolded coverage of membrane can effectively reduce resorption of grafted bone on the apical surface of implants and stimulate formation of the new bone in sinus augmentation.

[Maxillary sinus augmentation with simultaneous implantation using guided bone regeneration].

OBJECTIVE: To investigate the effect of new bone formation in sinus augmentation with guided bone regeneration (GBR) using collagen membranes. METHODS: The first maxillary molars of 18 adult female Beagle dogs were extracted and the sinus floors of both sides were lifted with simultaneous implantation. A combination of autografts and Bio-Oss in a 2:1 ratio was placed in the space under the membrane. On the experimental side in each dog, the collagen membrane was folded at the lateral osteotomy window, the apex of the implants and a certain part of palatal bone. On the contralateral control side, the collagen membrane only covered the osteotomy window. Six animals were sacrificed at 4, 12, and 24 weeks respectively after surgery. Gross observation, biomechanical testing and histological examinations were performed. RESULTS: The translocation of grafted materials and bone absorption were found on the top of implants in the control side, and the grafted materials kept original shape at the experimental side at 4th week. The granule of Bio-oss absorbed obviously at 12th and 24th week. The pull-out force increased with time. At 24th week, the force of pull out was 558.1 ± 37.4 N at the study side, and 471.4 ± 31.5 N at the control side. There was a significant difference in the pull-out force was noted between the two groups (P < 0.01). Histological examination showed new bone formation on the sinus floor, and the grafted materials gradually reduced with time CONCLUSIONS: GBR with the enfolded-coverage of the membrane can effectively decrease absorption of the grafted materialon the apical surface of implants and stimulate new bone formation in the sinus augmentation.

[Influence of bone quality on the stress distribution for three-posterior immediately loaded implants: a three-dimensional finite element analysis].

OBJECTIVE: To assess and compare the peri-implant stress distribution of three posterior implants under immediate loading with 4 different bone qualities using three dimensional (3D) finite element (FE) analysis. METHODS: A 3D finite element model representing three implants in a portion of mandible at the 654 region was developed, and three implants received a crown each. Four types of bone qualities (B1, B2, B3 and B4) were designed for the model. Load of 100 N was applied on the occlusal surfaces of the crowns at a 45° angle to the vertical axis of the implants. RESULTS: Von Mises stresses in the peri-implant bone of 4 in bone quality from B1 to B4 were (13.17 ± 9.32), (12.95 ± 9.14), (15.00 ± 9.44), and (16.81 ± 10.74) MPa, and those of 5 were (15.51 ± 10.32), (14.73 ± 8.96), (16.79 ± 8.40), and (18.34 ± 8.45) MPa. Stress in bone quality B4 showed the highest value, followed by B3 bone, the lowest stress were found in B1 and B2 bone. It was significantly different (P < 0.05). However, von Mises stresses in different quality of bone around 6 [(42.45 ± 25.71), (41.66 ± 25.29), (42.70 ± 23.24), (42.06 ± 23.66) MPa] were close to each other, and were as twice or three times as those of 4 and 5, irrespective of different bone qualities. CONCLUSIONS: The stress distribution around implant under immediate loading was not only affected by different bone qualities, but also by the direction of loading, and the latter may have a greater impact when a severe load delivered.

Experimental research of accurate reduction of zygomatic-orbitomaxillary complex fractures with individual templates.

PURPOSE: To develop a feasible intraoperative guiding device using computer-aided design and computer-aided manufacturing of individual templates to permit anatomic fracture reduction of zygomatic-orbitomaxillary complex (ZOMC) comminuted fractures. The simplicity and accessibility of this method should allow its widespread clinical application. MATERIALS AND METHODS: Under an institutional review board-approved protocol, diverse ZOMC fracture types were created in 6 cadaver heads with a hammer and a saw, and preoperative multislice spiral computerized tomography scan and 3-dimensional reconstruction were performed. Three individual templates were made by computer-aided design and computer-aided manufacturing, and the fractures were repaired under the guidance of individual templates. A clinical case was carried out with this method. After surgery, the outcome evaluation was completed by superimposing the postoperative computed tomographic model onto the planned model. RESULTS: Successful planning and repositioning of the 6 cadavers and a clinical patient were achieved using this method. Computer-aided design and computer-aided manufacturing of individual templates were successfully used in all cases at the time of surgery. Postoperative computed tomographic scans confirmed anatomic repair in all cases. CONCLUSIONS: A feasible intraoperative ZOMC fracture monitoring and reduction guidance device has been developed. This technique is a simple, economical, and readily accessible method of comminuted ZOMC fracture reduction that can be learned and used rapidly.

Accuracy of intraoral vertical ramus osteotomy with a stereolithographic template.

Various modifications have been described to improve the accuracy in intraoral vertical ramus osteotomy (IVRO), but there was not a measurable facility to determine the osteotomy line. The purpose of this study was to evaluate the accuracy of the computer tomography (CT)-based osteotomy template on cadaver mandibles and to assess the outcome after IVRO correcting mandibular prognathism. Four human wet cadaver heads were subjected to a high-resolution multislice spiral CT scan. After the virtual osteotomies in the planning program, the individual osteotomy templates were produced by stereolithography. A stable and secure fit of the stereolithographic templates was achieved via the individual CT-based osteotomy template. The osteotomy lines were performed exactly as planned in the virtual osteotomies planning program. Similar sound outcome was also observed in the clinic. Use of the CT-based osteotomy templates is a safe method for osteotomy. It is rather convenient for vertical osteotomy in IVRO increasing the intraoperative accuracy and efficiency.

Fabrication of a surgical template for orbital implant placement: a case report.

Implant placement in orbital sites is challenging because of limited bone volume and poor bone quality. Preoperative optimal implant planning and intraoperative guides are important to ensure success. This article describes the use of computer simulation for implant insertion and fabrication of a surgical template as a drilling guide for orbital implant placement. A 29-year-old woman with a right orbital defect underwent computerized tomographic scanning, and the data were processed with interactive software to simulate orbital implant placement. A surgical template that served as a drilling guide was designed and fabricated to transfer orbital recipient site information from the three-dimensional computer model into the actual orbital implant sites. Three craniofacial implants were placed in the 7:00, 8:00, and 11:00 positions. No unexpected complications or injuries were encountered during the surgery. Magnetic abutments were attached to the implants 2 weeks later. The definitive facial prosthesis was fitted 6 months later, with excellent esthetic results. The surgical template contributed to the success of this treatment.

[CT multiplanar image anatomic study on orbital bone used for implant operation].

OBJECTIVE: To evaluate the orbital bone quantity by spiral computer tomography (CT) for orbital implant operation. METHODS: Fifty-two normal skull specimens with marks received spiral CT scan and their multiplanar images were obtained. The quantity (length x width) were measured on multiplanar images. RESULTS: The right orbital bone quantity at 7:00 was the highest, average 11.91 mm x 8.38 mm, and at 3:00 was the lowest, average 2.31 mm x 1.34 mm. The left orbital bone quantity at 5:00 was the highest, average 12.03 mm x 8.56 mm, and at 9:00 was the lowest, average 2.44 mm x 1.29 mm. There had no significance correlation with gender at the same position in both sides. CONCLUSION: Useful data had been obtained for the selection of the placement sites, direction, length, and diameter of orbital implants.

[Clinical application of computer assisted technology based spiral CT scan for locating impacted tooth].

OBJECTIVE: To evaluate clinical value of computer assisted technology for locating the impacted tooth. METHODS: Thirty-five patients with impacted tooth were received spiral CT scan. The DICOM data were processed by Simplant software for locating the impacted tooth. RESULTS: The reconstruction images clearly showed detail of the impacted teeth, including 3D surface image, eruption orientation, buccal and lingual location, medial and distal location and relationship with dentition and circumambient anatomic structure. CONCLUSION: The computer assisted technology can localize the impacted tooth precisely and provide valuable information for clinical treatment.

[Clinical study on delayed flapless implants placement after bone powder grafted immediately in postextraction sockets].

PURPOSE: To explore and evaluate the clinical outcome of delayed flapless implant placements after bone powder grafted immediately in postextraction sockets. METHODS: 23 patient requiring dental implants after postextractions were selected for this study. The fresh sockets with at least 3 walls (3 or 4 walls) were immediately grafted and filled with artificial bone powders (Bio-oss and demineralized bone powders), covered by ultra-thin titanium membranes. Bone graft got to or 2-3mm higher than the top level of the sockets. 3 months later, the alveolar bone heights were checked by routine X-ray examination. And alveolar bone ridge widths were measured by bone-width gauges. The alveolar bones were confirmed sufficient to accommodate the implant with at least 4.0mm in diameter and 9mm in length. Then flapless implant placements were performed. The primary stability of the implants was measured. The implants were followed up and success rate of implant was evaluated. RESULT: The alveolar bone height and width were basically maintained without depression and atrophy through clinical observation and X-ray examination. Flapless implant placements were performed with minor local reaction. The primary stability of 36 implants all attained to 30N. Failure did not happen during a followed up period of by 6-62 months. CONCLUSION: After bone powder grafted immediately in postextraction sockets, sufficient alveolar bone volume for implants can be preserved. Flapless implant placements in sufficient bone support can effectively simplify the preoperative examination and surgical procedures, reducing local reaction. Delayed flapless implant placements after bone powder grafted immediately in postextraction sockets is an effective design and method of dental implantation.