[Evaluation of digital technology for orthognathic surgery in 25 patients].

PURPOSE: To use three-dimensional reconstruction measurement, preoperative diagnosis, surgical design, surgical simulation, guide plate production, navigation verification and effect evaluation of orthognathic surgery assisted by digital technology, in order to explore more scientific and reasonable programs and procedures of orthognathic surgery. METHODS: Twenty-five patients with congenital dental and maxillofacial deformity were selected as the experimental subjects, craniofacial spiral CT was conducted before surgery and CT data were imported into Mimics 20.0 software to establish a 3D head digital model. The bone landmarks in three-dimensional reconstruction digital model were selected, measured, analyzed and diagnosed, and the design of the surgical plan and the production of the guide plates were performed. Surgical navigation system was used to confirm the maxillary position, verify the bone retention and guide precise bone grinding during operation. Craniofacial spiral CT was conducted 1 week after surgery for postoperative validation of the surgical design protocol. Statistical analysis was performed using SPSS 24.0 software package. RESULTS: All 25 patients were operated according to the digital orthognathic surgery design and procedure.There were no significant differences in X, Y and Z three-dimensional directions in 10 actual landmarks between the postoperative actual head model and the preoperative predictive head model（P>0.05）. CONCLUSIONS: Orthognathic surgery assisted by digital technology has the advantages of precision and minimal invasiveness.

[The effect of orthognathic surgery on speech function in patients with skeletal Class â ¢ malocclusion].

PURPOSE: To investigate the influence of the position of the upper and lower jaws on the anatomical structure of pharynx before and after orthognathic surgery in patients with skeletal Class Ⅲ malocclusion. METHODS: Craniofacial CT scan and speech data were collected from 31 patients with skeletal Class Ⅲ malocclusion before and 3 months after surgery. The collected CT data was imported into Dolphin imaging 11.95 software to establish a digital original model, and the anatomical structure of the pharynx was measured and analyzed. Speech data were analyzed objectively and subjectively by Computerized Speech Lab 4500b and professional speech specialists. Statistical analysis was performed using SPSS 24.0 software package. RESULTS: The distance from the lower edge of the soft palate to the posterior pharyngeal wall, the shortest distance from the posterior margin of the tongue to the posterior pharyngeal wall and its corresponding cross-sectional area were significantly different from those before surgery (P<0.05). The changes of SNA, SNB, ANB, OJ, and OBJ before and after surgery were significant in this series. Importantly, the speech intelligibility of orthognathic patients before and after surgery changed significantly subjectively (P<0.05). Objectively, the postoperative vowels /a/B2, B3, B4, /i/B1,B2, /u/B1,B2 and B4 of the patients were significantly different from those before surgery. There was no significant difference in the lower limit frequency of the consonants /x/, /zh/, /s/, the energy value of /zh/ and the grammatical form of /z/ before and after surgery. The maxillary advancement distance was highly correlated or significantly correlated with △S1, △VOP, and voice changes. CONCLUSIONS: Orthognathic surgery moves the upper and lower jaws to cause changes in the anatomy of the pharyngeal cavity, leading to changes of postoperative speech.

[Three dimensional study on change ratios of hard and soft tissue after orthognathic surgery].

PURPOSE: To investigate the change ratios of soft and hard tissue after orthognathic surgery three-dimensionally in osseous Class Ⅲ patients, in order to predict postoperative soft tissue three-dimensionally. METHODS: Twenty adult patients were selected as the experimental group, craniofacial spiral CT and three-dimensional (3D) stereophotogrammetry were conducted 2 weeks before surgery and 3 months after surgery. Dolphin imaging software was used to establish 3D image digitizing model and 3D measurement coordinate system. Nineteen soft and hard tissue land marks were selected and matched into 12 pairs. 3D coordinate value of these landmarks were read both before and after surgery and were used for statistical analysis with SPSS 22.0 software package. RESULTS: There was a linear relationship only in Pn/A, Gn'/Gn and Me'/Me in X axis, in Gn'/Gn in Y axis and all pairs of landmarks had a close correlation except UL'/UI and UL/SPr in Z axis. Additionally, the change ratio between soft and hard tissue landmarks of mandible was greater than maxilla. CONCLUSIONS: The changes of soft and hard tissue after orthognathic surgery only lie in Z axis(forward and backward), each pair of matched landmarks exhibits a linear relationship, and the change ratio of mandible is greater than the maxilla.

DNA methylation profiling in different phases of temporomandibular joint osteoarthritis in rats.

OBJECTIVE: Temporomandibular joint osteoarthritis (TMJOA) is a complex disease with strong genetic and epigenetic components in its pathogenesis. The aim of this study was to evaluate DNA methylation in mandibular head cartilage in different phases of experimentally-induced TMJOA in rats. DESIGN: DNA methylation was evaluated using microarrays in the mandibular head cartilage of early, intermediate and late stage experimentally-induced TMJOA, and of the normal age-matched control groups. Genes with differentially methylated CpG sites were analyzed to reveal the over-represented gene ontologies and pathways at different stages, and were compared with published expression profiles to assess their overlappings. The DNA methylation patterns of the target genes were validated by methylated DNA immunoprecipitation qPCR in additional independent cartilage samples and mRNA levels were analyzed by real-time PCR. RESULTS: We observed 9489 differentially methylated regions between the TMJOA and controls. A total of 440 consistently altered genes were revealed in all three stages; most (80%) were hypomethylated and many were associated with cell cycle regulation. We also detected different DNA methylation changes in early and late stage TMJOA (Rearly=0.68, Rlate=0.47), while the differences between age-matched healthy cartilage were subtle. Strong inverse changes between methylation status and mRNA levels were confirmed in Adamts5, Chad, Cldn11 and Tnf. CONCLUSIONS: Our data reveals dynamic DNA methylation patterns during the progression of TMJOA, with a different host of genes and pathways. The changes of cartilage DNA methylation patterns might contribute to understand the etiologic mechanisms of TMJOA epigenetically.

[The change of patients' psychosomatic symptoms after orthognathic surgery].

PURPOSE: To assess the change of patients' psychological status before and after orthognathic surgery. METHODS: The psychological status in 36 patients were assessed before and after orthognathic surgery using the SCL-90 questionnaire. The patients were allowed to evaluate the changes of mastication, facial aesthetics, pronunciation and function of temporomandibular joint subjectively through the questionnaire. The data were analyzed using SPSS13.0 software package. RESULTS: Six factors including obsessive-compulsive symptoms, interpersonal sensitivity, depression, anxiety, phobic anxiety and psychoticism were significantly higher than norm preoperatively. No obvious abnormalities were found 2 years after operation. The self-evaluated quotas by patients after operation were significantly improved compared with those preoperatively. CONCLUSIONS: The patients' psychosomatic symptoms are significantly improved after operation. No significant difference is found compared with ordinary people concerning psychological health.

Fabrication of electric papers of graphene nanosheet shelled cellulose fibres by dispersion and infiltration as flexible electrodes for energy storage.

An electrically conductive and electrochemically active composite paper of graphene nanosheet (GNS) coated cellulose fibres was fabricated via a simple paper-making process of dispersing chemically synthesized GNS into a cellulose pulp, followed by infiltration. The GNS nanosheet was deposited onto the cellulose fibers, forming a coating, during infiltration. It forms a continuous network through a bridge of interconnected cellulose fibres at small GNS loadings (3.2 wt%). The GNS/cellulose paper is as flexible and mechanically tough as the pure cellulose paper. The electrical measurements show the composite paper has a sheet resistance of 1063 Ω□(-1) and a conductivity of 11.6 S m(-1). The application of the composite paper as a flexible double layer supercapacitor in an organic electrolyte (LiPF(6)) displays a high capacity of 252 F g(-1) at a current density of 1 A g(-1) with respect to GNS. Moreover, the paper can be used as the anode in a lithium battery, showing distinct charge and discharge performances. The simple process for synthesising the GNS functionalized cellulose papers is attractive for the development of high performance papers for electrical, electrochemical and multifunctional applications.

Transparent luminescent bulk nanocomposites of polysiloxane embedded with CdS nanocrystallines by a direct dispersion process.

Transparent luminescent bulk nanocomposites of polysiloxane (PSO) embedded with semiconductor nanocrystals (NCs) have been fabricated by the direct dispersion of CdS NCs in alkyl-(poly)siloxane (APS) followed by co-polymerization. The non-polar characteristics of the APS precursor are compatible with the CdS NC surface (oleylamine), which allows the direct dispersion of the CdS NCs without the need of any surfactant exchange. Chemical crosslinking of the NC-APS dispersion via hydrosilylation between Si-H and the vinyl group in APS immobilizes the CdS NCs in the polysiloxane network. Net-shaped three-dimensional bulk transparent polysiloxane/CdS NC composites were obtained by liquid casting of the NC-precursor dispersion and chemical crosslinking. The PSO/CdS NC composites show visible luminescence under ultraviolet excitation and the luminescent color is tunable from blue to red by controlling the NC concentration in the composite. Photoluminescence spectral analyses reveal the origin of the luminescence as being from the defect emission of the CdS NCs (550-900 nm) and an emission from the PSO matrix (380-550 nm). The luminescent spectra covered a wide range from the ultraviolet to the near-infrared region. The luminescence of the PSO/CdS NC nanocomposites was stable without any apparent degradation after exposure to air for a long time. This simple direct dispersion process is feasible for the fabrication of luminescent nanocomposites with useful optical properties for potential applications in optics and photoelectron devices.

[Quantity of released nickel ion from Ni-Cr alloy of compound galvano-ceramic bridge].

OBJECTIVE: To evaluate the biological safety of compound galvano-ceramic bridge by measuring the consistency of released nickel ion of the galvano-form slices cohered with Ni-Cr alloy slice specimens which were immersed in artificial saliva. METHODS: Specimens were divided into five groups with four tests and one control. Test specimens were made into the structure like rectangle sandwich that one side of Ni-Cr alloy was cohered to the center surface of galvano golden base of 0.2 mm and another side was fused porcelain with the thickness of 0.3 mm (group A), 0.5 mm (group B), 1.0 mm (group C), and 0.3 mm (group D). And the Ni-Cr alloys were totally embedded in galvano golden base and firing porcelain. Naked Ni-Cr alloy was taken as control. Group D was immersed into acid artificial saliva (AS) with high fluoride, while others were in acid AS at 37 degrees C for 120 h. Then the consistency of released nickel ion in the solution was measured with inductively coupled plasma-atomic emission spectrometry (ICP-AES). RESULTS: Nickel ions detected in the artificial saliva for the groups A, B, C, and D in acid AS with or without high fluoride were all under 0.005 mg/L Significant differences were found between each test group and the control [(0.65 +/- 0.45) mg/L]. CONCLUSIONS: Galvano-ceramic bridge, Ni-Cr alloy bridge with fused porcelain and golden base, shows biological safety responsible for the consistency of released nickel ion.