IGF2BP1 promotes LPS-induced NFκB activation and pro-inflammatory cytokines production in human macrophages and monocytes.

BACKGROUND: Lipopolysaccharide (LPS)-induced macrophage/monocyte activation and pro-inflammatory cytokines production are important mediators for periodontitis progression. The current study tested the potential role of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in the process. METHODS: THP-1 human macrophages and primary human peripheral blood mononuclear cells (PBMCs) were treated with LPS. mRNA and protein expression of IGF2BP1 were tested by qPCR and Western blotting assay. IGF2BP1 expression was altered by shRNAs or CRISPR/Cas-9 gene editing methods. LPS-induced cytokine production was tested by ELISA assay. Cytokine mRNA expression was tested by the quantitative real-time reverse transcriptase polymerase chain reaction (qPCR) assay. RESULTS: In THP-1 human macrophages and PBMCs, treatment with LPS induced mRNA and protein expression of IGF2BP1. IGF2BP1 silencing (by targeted shRNAs) or CRISPR/Cas-9 knockout largely inhibited LPS-induced production of multiple pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß and IL-6. Conversely, forced over-expression of IGF2BP1 facilitated LPS-induced pro-inflammatory cytokines production in THP-1 cells. For the mechanism study, we show that IGF2BP1 co-immunoprecipitated with p65-p52 nuclear factor kappa B (NFκB) complex in nuclei of LPS-treated THP-1 cells. Significantly, LPS-induced p65-p52 nuclear translocation and NFκB activation were inhibited by IGF2BP1 silencing or CRISPR/Cas-9 knockout. CONCLUSION: IGF2BP1 promotes LPS-induced NFκB signalling and transcriptional activation in human macrophages and monocytes.

Effect of sinus membrane perforation on the survival of implants placed in combination with osteotome sinus floor elevation.

This study was conducted to evaluate implant survival with regard to effects of sinus membrane perforation that occurred during osteotome sinus floor elevation (OSFE). The study group consisted of 42 patients with edentulous posterior maxilla. Implants placement combined with OSFE without a grafting material was performed. All patients underwent a radiographic examination before surgery, to reveal the periimplant bone formation immediately after implant placement and 6 to 33 months later. Sinus membrane perforations were detected in 6 patients, and 6 implants were inserted in 6 sinus sites. No infection occurred in all sites, and all implants succeeded in the observation follow-up period. There was a 100% survival rate of implant in perforated sinuses, the same as in intact sinuses. Within the limits of this study, we can conclude that perforation of the sinus membrane does not compromise the short-term survival of dental implants placed in combination with OSFE.

Implant-bone interface stress distribution in immediately loaded implants of different diameters: a three-dimensional finite element analysis.

PURPOSE: To establish a 3D finite element model of a mandible with dental implants for immediate loading and to analyze stress distribution in bone around implants of different diameters. MATERIALS AND METHODS: Three mandible models, embedded with thread implants (ITI, Straumann, Switzerland) with diameters of 3.3, 4.1, and 4.8 mm, respectively, were developed using CT scanning and self-developed Universal Surgical Integration System software. The von Mises stress and strain of the implant-bone interface were calculated with the ANSYS software when implants were loaded with 150 N vertical or buccolingual forces. RESULTS: When the implants were loaded with vertical force, the von Mises stress concentrated on the mesial and distal surfaces of cortical bone around the neck of implants, with peak values of 25.0, 17.6 and 11.6 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains (5854, 4903, 4344 muepsilon) were located on the buccal cancellous bone around the implant bottom and threads of implants. The stress and strain were significantly lower (p < 0.05) with the increased diameter of implant. When the implants were loaded with buccolingual force, the peak von Mises stress values occurred on the buccal surface of cortical bone around the implant neck, with values of 131.1, 78.7, and 68.1 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains occurred on the buccal surface of cancellous bone adjacent to the implant neck, with peak values of 14,218, 12,706, and 11,504 microm, respectively. The stress of the 4.1-mm diameter implants was significantly lower (p < 0.05) than those of 3.3-mm diameter implants, but not statistically different from that of the 4.8 mm implant. CONCLUSIONS: With an increase of implant diameter, stress and strain on the implant-bone interfaces significantly decreased, especially when the diameter increased from 3.3 to 4.1 mm. It appears that dental implants of 10 mm in length for immediate loading should be at least 4.1 mm in diameter, and uniaxial loading to dental implants should be avoided or minimized.

Influence of Trabecular Bone on Peri-Implant Stress and Strain Based on Micro-CT Finite Element Modeling of Beagle Dog.

The objective of this investigation is to analyze the influence of trabecular microstructure modeling on the biomechanical distribution of the implant-bone interface. Two three-dimensional finite element mandible models, one with trabecular microstructure (a refined model) and one with macrostructure (a simplified model), were built. The values of equivalent stress at the implant-bone interface in the refined model increased compared with those of the simplified model and strain on the contrary. The distributions of stress and strain were more uniform in the refined model of trabecular microstructure, in which stress and strain were mainly concentrated in trabecular bone. It was concluded that simulation of trabecular bone microstructure had a significant effect on the distribution of stress and strain at the implant-bone interface. These results suggest that trabecular structures could disperse stress and strain and serve as load buffers.

Non-joint effusion is associated with osteoarthritis in temporomandibular joints with disk displacement.

PURPOSE: The aim of this study was to examine the possible association between different grades of joint effusion (JE) and osteoarthritis (OA) in temporomandibular joint (TMJ) anterior disk displacement without reduction (ADDwoR). MATERIAL AND METHODS: A sample of 101 female patients 20-40 years of age with unilateral TMJ ADDwoR were retrospectively reviewed. JE and OA were diagnosed with magnetic resonance imaging (MRI). JE was subdivided into three different grades: grade 0, no or minimal effusion; grade 1, moderate effusion; and grade 2, extensive effusion. Eight categories of degenerative changes were used for screening for the existence of OA. Cases with no less than one type of degenerative change were diagnosed as OA. RESULTS: In all, 71 patients (70.3%) were diagnosed as having OA in the joints with disk displacement. In the univariate analysis, the proportion of subjects with non-JE (grade 0) was higher in the OA group (p = 0.003), while the proportion of subjects with extensive effusion (grade 2) was lower in the OA group (p = 0.02). In the multivariate logistic regression analysis, non-JE was independently associated with the development of OA (odds ratio = 5.68, 95% confidence interval = 1.10-29.37, P = 0.04). CONCLUSION: The results suggested that non-JE was associated with OA in the joints with ADDwoR.

Influence of orthotropy on biomechanics of peri-implant bone in complete mandible model with full dentition.

OBJECTIVE: The study was to investigate the impact of orthotropic material on the biomechanics of dental implant, based on a detailed mandible with high geometric and mechanical similarity. MATERIALS AND METHODS: Multiple data sources were used to elaborate detailed biological structures and implant CAD models. In addition, an extended orthotropic material assignment methodology based on harmonic fields was used to handle the alveolar ridge region to generate compatible orthotropic fields. The influence of orthotropic material was compared with the commonly used isotropic model and simplified orthotropic model. RESULTS: The simulation results showed that the values of stress and strain on the implant-bone interface almost increased in the orthotropic model compared to the isotropic case, especially for the cancellous bone. However, the local stress concentration was more obvious in the isotropic case compared to that in orthotropic case. The simple orthotropic model revealed irregular stress and strain distribution, compared to the isotropic model and the real orthotropic model. The influence of orthotropy was little on the implant, periodontal ligament, tooth enamel, and dentin. CONCLUSION: The orthotropic material has significant effect on stress and strain of implant-bone interface in the mandible, compared with the isotropic simulation. Real orthotropic mechanical properties of mandible should be emphasized in biomechanical studies of dental implants.

Chronological changes in the microstructure of bone during peri-implant healing: a microcomputed tomographic evaluation.

Our objectives were to examine the titanium-bone interfaces chronologically and to clarify the process of osseointegration using microcomputed tomography (microCT). The mandibular premolars of 3 dogs were extracted and 12 weeks later 2 Straumann dental implants were installed in each quadrant. The microstructural changes at the bone-implant interface at the first, fourth, and eighth weeks after installation were evaluated by microCT and a 3-dimensional image was constructed. The microstructural measurements at the bone-implant interface, including the trabecular number (Tb.N), bone volume fraction (BV/TV), structure model index (SMI), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp) and connectivity density (Conn.D), were measured. Experimental outcomes were analysed for correlations between time and microstructural variables of trabecular bone. Tb.N increased significantly during the eighth week compared with that during the first and fourth week (p=0.001, 0.002). BV/TV increased generally with time and there were significant differences (p=0.003) between each time group. While Tb.Sp decreased with time and changed significantly during the eighth week compared with that during the first week (p=0.021), differences in SMI, Tb.Th and Conn.D did not differ significantly according to time of implant. The significant increase in the Tb.N and BV/TV during the eighth week after insertion of implants indicates that the formation of new bone before the eighth week is the key to osseointegration.

Magnetic resonance imaging assessment of temporomandibular joint soft tissue injuries of intracapsular condylar fracture.

We evaluated the soft tissue of the temporomandibular joint (TMJ) with magnetic resonance imaging (MRI) after intracapsular condylar fracture. Eighteen consecutive patients (19 TMJ) were diagnosed between 1 January 2010 and 30 October 2011. They were examined using bilateral sagittal and coronal MRI, which were obtained immediately after injury to assess the displacement of the disc, whether there was a tear in capsule or the retrodiscal tissue, and whether there was an effusion in the joint. On the affected side MRI showed disc displacement in 15 of 19, tears in the capsule in 9, and tears in the retrodiscal tissue in 16. All 19 had joint effusions. It also showed 2 joints with abnormalities on the unaffected side. We conclude that MRI is useful for diagnosis and for estimating the amount of damage to the TMJ, and is helpful in planning treatment.

[Clinical application of a self-developed bone collector in dental implantation].

OBJECTIVE: To introduce a self-developed bone collector designed by the authors and evaluate its effect in clinical application. METHODS: A self-developed bone collector was used in 38 patients who underwent the dental implant operation from May 2008 to October 2009. During the operation the bone particles were harvested, which was used for the reconstruction of the bone defects around the implant simultaneously. The defects were fenestrate in 29 regions and triangle in 23 regions on buccal or lingual side of the dental implants. RESULTS: All cases had no surgical wound infection and dehiscence 7 - 10 days after operation. Three to six months after implantation, the X-ray showed that all the dental implants had perfect osseointergration and the alveolar bone were successfully augmented. CONCLUSIONS: Bone debris harvested by self-developed bone collector could repair small peri-implant bone defects, which is simple to use in clinic.

Real time 3D simulation for nose surgery and automatic individual prosthesis design.

This paper presents an intuitive nose surgery planning and simulation system, using 3D laser scan image and lateral X-ray image, to provide high quality prediction of the postoperative appearance, and design the patient specific prosthesis model automatically. After initial registration, the internal surface of soft tissue at the nose region was generated by the statistical data for soft tissue thickness adapted by the individual thickness information from the X-ray image. Then, the sketch contour of the 3D scan data on the lateral X-ray image was modified manually or adjusted automatically according to some aesthetic statistical data, to drive the simulation in real time by the state-of-the-art Laplacian surface deformation method. When satisfied with the 3D postoperative appearance, the deformation was mapped to the internal surface of soft tissue, and the change before and after simulation was utilized to generate the patient specific prosthesis model automatically. The surgeons who used the system confirmed that this planning system is attractive and has potential for daily clinical practice.

[Infections of the head and neck leading to descending necrotizing mediastinitis: management of 9 cases].

OBJECTIVE: To report nine cases of descending necrotizing mediastinitis (DNM) and to summarize the management experience. METHODS: Between December 2005 and December 2008, nine patients (mean age, 55.7 years; age range, 38 to 78 years) with DNM were treated. Eight patients underwent surgical drainage of the involved cervical region and mediastinum (4 with cervical drainage alone; 4 with cervical drainage and right thoracotomy). RESULTS: Two patients died, one of them refused surgical therapy and the other one died of multiorgan failure related to postoperative septic shock. Seven patients recovered. The mortality rate was 22%. CONCLUSIONS: Delayed diagnosis and inadequate drainage are the main causes of high mortality rate of DNM. Aggressive surgical drainage and debridement of the neck and mediastinum by a multidisciplinary team of surgeons are very important in the treatment of DNM.

Effect of diameter and length on stress distribution of the alveolar crest around immediate loading implants.

BACKGROUND: Many clinical observations have shown that immediate loading is indicated when the stabilization of the bone/implant is optimal and when the estimated loads are not excessively high. Nonetheless, more experimental studies are needed to consider the immediate loading protocol as a safe procedure. Mechanical analysis using the finite element (FE) method analysis has been employed by many authors to understand the biomechanical behavior around dental implants. PURPOSE: This study was to evaluate the effect of the diameter and length on the stress and strain distribution of the crestal bone around implants under immediate loading. MATERIALS AND METHODS: By an ad hoc automatic mesh generator, high-quality FE models of complete range mandible was constructed from computer tomography, with three Straumann (Straumann Institute, Waldenburg, Switzerland) implants of various sizes embedded in the anterior zone. The implant diameter ranged from 3.3 to 4.8 mm, and length ranged from 6 to 14 mm, resulting in seven designs. The implant-bone interface was simulated by nonlinear frictional contact algorithm. For each design, vertical and oblique loadings of 150 N were applied, respectively, to each implant, and stresses and strains in the surrounding cortical bone were evaluated. RESULTS: The biomechanics analysis provided results that the oblique loading would induce significantly higher interfacial stresses and strains than the vertical loading, while the intergroup stress difference significant levels was evaluated using t-tests method and the level of significance (.05) that was accepted for significance. Under both loadings, the maximal values were recorded in the 3.3 (diameter) x 10 (length) mm implant configuration, whose mean and peak values were both higher than that of others with significant statistical differences. The second maximal one is 4.1 x 6 mm configuration, and the minimal stresses were recorded in 4.8 x 10 mm configuration, whose strains were also near to lowest. CONCLUSIONS: Increasing the diameter and length of the implant decreased the stress and strain on the alveolar crest, and the stress and strain values notably increased under buccolingual loading as compared with vertical loading, but diameter had a more significant effect than length to relieve the crestal stress and strain concentration.

[Three dimension finite element analysis of anisotropic mandible with dental implants effect on implant-bone interface].

OBJECTIVE: To establish anisotropic mandible model with dental implants and to investigate the effect of anisotropy material on stress and strain distribution of implant-bone interface. METHODS: Three-dimensional finite element models of whole mandible with anisotropic and equivalent isotropic material were created by CT scanning and universal surgical integration system (USIS) software developed by the authors. Two ITI threaded implants were implanted in the posterior teeth area. The values of principal stress and principal strain on the bone around dental implants were calculated in two different finite element models with buccolingual load. RESULTS: In the anisotropic mandible model, nearly all values of the principal stress and principal strain on cortical and cancellous bone increased compared with the equivalent isotropy model, 2.1%-74.1% for principal stress and 4.7%-57.3% for principal strain, but 10. 3%-71.4% for principal stress and 19.5%-63.4% for principal strain on cancellous bone. CONCLUSIONS: In the three-dimensional finite element analysis, anisotropic mandible model with dental implants has an apparent effect on the stress and strains of the implant-bone interface. Anisotropic mechanical properties of mandible should be emphasized in biomechanical study.

[Experimental study on the reconstruction of mandibular symphyseal defects by internal tri-focal distractor].

OBJECTIVE: To introduce the internal tri-focal distractor developed by the authors and evaluate its primary application and feasibility in animal experiment. METHODS: Four hybrid dogs were selected and segmental resection at the mandibular symphysis was performed. Two transfer disks, 10 mm in width, were respectively fixed at the two ends of bone defect and the internal tri-focal distractor was installed. The force was applied one week after the operation, with a tractive speed of 0.5 mm/12 h. After 13 - 16 days, the traction was completed when the two transfer disks were combined. The occlusal films were taken at the 1st day, 4th, 8th and 12th week after traction. The animals were killed at the 12th week, samples of the traction area taken and histological examination performed. Finally, the new bone formation was observed. RESULTS: All the animals survived in the experiment, abruption and rust-eaten was not found in distractor. In the 12th week after installation, new bones in traction gap were mature and bony union between the two transfer dishes was accomplished. CONCLUSIONS: The internal tri-focal distractor used in this study may become a potential device in reconstruction of mandibular symphyseal defects.

[Establishment of a three-dimensional finite element model of mandible with dental implants for immediate loading].

PURPOSE: To establish a three-dimensional finite element model of mandible with dental implants for immediate loading, which will provide a basis for study of the biomechanical characteristics of the immediate loading implant-bone interface. METHODS: A female edentulous mandible was adopted for CT scanning, the scanned data were saved with the form of DICOM, and then input into compute. Universal Surgical Integration System which was developed by ourselves and ANSYS 10.0 were used to divide mesh and establish finite element model. Three dental implants simulating the real shape of ITI thread implant were embedded in the anterior region of the mandible, of which implant-bone interface was granted with situation of smooth friction simulating the case of immediate loading. RESULTS: The accurate finite element model of mandible with dental implants for immediate loading was established, which included 127811 tetrahedron elements with 182252 nodes. A single dental implant model comprised 13924 elements with 21420 nodes, the thread of it was continuous and smooth. CONCLUSION: The biomechanical similarity, the geometrical analogy and clinical indication of the model were quite good. The three-dimensional finite element model developed by this method can apply for precise analysis of the rule of biomechanics on the implant-bone interface for immediate loading.

[A finite element analysis system for two-demension morphological analysis of the soft tissue in orthognathic surgery].

OBJECTIVE: To evaluate a finite element method (FEM) for analysis of the cranial-facial morphology. METHODS: The two-dimensional finite element analysis system was established and used to analysis the lateral side morphology of the soft tissue by the change of each finite unit of the soft tissue in a X-ray cranial-facial lateral cepholometrics film. RESULTS: The finite element analysis system was showing very well in the figures and data made by the system. CONCLUSION: Finite element analysis system may be a good supplement of the traditional X-ray cephalometrics to the soft tissue of orthognatics.