[Evaluation of low intensity Nd: YAG laser and traditional drugs in the treatment of myofascial pain].

PURPOSE: To evaluate the efficacy of low intensity Nd: YAG laser and traditional drugs in the treatment of myofascial pain (MP). METHODS: Eighty patients with MP were divided into laser group(n=40) and traditional medicine group(n=40) according to the principle of randomization and double-blindness. The patients in the laser group were treated with low intensity Nd :YAG laser(1 064 nm, 8 J/cm2, 250 mW) , with an interval of 48 h between the two laser treatments. The whole course of treatment was 10 times. Patients in the traditional medicine group uesd celecoxib capsules, 1 capsulet each time(0.2 g), twice a day for 2 weeks. Before and after each treatment, mouth opening, protrusion excursion, lateral movement of the affected side and lateral movement of the contralateral side were measured, and pain visual analogue scores (VAS) were measured and recorded. The data were statistically analyzed with SPSS 22.0 software package. RESULTS: Patients in laser group had significantly improved mandibular function and movement status(P＜0.05) and pain symptoms(P＜0.05); patients in traditional medicine group had the same significant improvement on mandibular functional movement status(P＜0.05) and pain symptoms (P＜0.05). The total effective rate of the two groups had no significant difference(P＞0.05). The VAS score of patients in laser group was lower than that of traditional medicine group, but the difference was not significant(P＞0.05). CONCLUSIONS: Low intensity Nd: YAG laser and traditional medicine can effectively relieve the symptoms of myofascial pain and improve mandibular function and movement. Laser treatment has the advantages of short course of treatment, high efficiency, no pain and fewer side effects, which is worthy of clinical application.

[Influence of bilateral coronoidectomy on temporomandibular joint stress distribution after costochondral graft reconstruction: a finite element analysis].

PURPOSE: To explore the effect of bilateral coronoidectomy on stress distribution after reconstruction of temporomandibular joint (TMJ) by costochondral graft. METHODS: Ten groups of models were established to simulate costochondral graft reconstruction with simultaneously different distances (0, 2, 4, 6, 8 mm) of mandibular advancement, with or without coronoidectomy. Force and stress distribution in the rib-cartilage area were analyzed by finite element analysis. RESULTS: In the process of bilateral joint reconstruction with simultaneously mandible advancement ranging from 0 mm to 8 mm, when the coronoid processes were retained, the forward deformation of the cartilage occurred and the shear force decreased in turn, from 113.2 N to 26.7 N on the left side and from 133.7 N to 1.9 N on the right side. When the coronoid processes were removed, the cartilage deformed backward and the shear force increased successively, from 94.6 N to 188.5 N on the left and 70.1 N to 157.7 N on the right. The stress in the neck was obviously concentrated when mandible advanced 8 mm. CONCLUSIONS: Coronoidectomy has an important impact on stress distribution in the TMJ area, and keeping the coronoid process is beneficial to maintain the mechanical balance. Bilateral CCG reconstruction with coronoidectomy for lengthy mandible advancement (≥ 8 mm) may lead to prominent increase in shear force beyond CCG resistance, resulting in a costal-cartilage junction fracture.

[Accuracy of implantation between two immediate implantation methods in mandibular molars].

PURPOSE: To compare the accuracy of implant placement between modified and traditional immediate implant placement in mandibular molar regions. METHODS: Twenty-four patients were selected for immediate implantation in the molar area including 24 implantation sites. Preoperative cone-beam CT(CBCT) was conducted and then digital software Simplant 18.0 was used to design the ideal three-dimensional position of the implants. In the experimental group, the implant socket was prepared first according to reference of the remaining natural teeth, then the implant was implanted after minimally invasive extraction. Twelve patients in the control group underwent immediate implantation by traditional immediate implant procedures. Minimally invasive extraction, then socket preparation, and final implanting were performed. All patients underwent CBCT after surgery. Implant sites designed prior to surgery and actual implant sites differences between modified and traditional immediate implant placement were measured by Simplant 18.0 and compared with SPSS 17.0 software package. RESULTS: In the experimental group and control group, the measured average deviation were as follows, the angle was (4.492±0.912)° and (7.255±1.307)°, respectively; The horizontal error of the implant shoulder was (0.379±0.083) mm and (1.229±0.270) mm, respectively; The measuring horizontal error of the implant apex was (1.263±0.267) mm and (2.183±0.264) mm, respectively; The calculative horizontal error of the implant apex was (1.324±0.203) mm and (2.709±0.383) mm, respectively; Depth error of the implant apex was (0.663±0.123) mm and (1.533±0.155) mm, respectively, which were significantly lower than those of the control group. CONCLUSIONS: Compared with the traditional method, modified immediate implantation can improve the accuracy of implantation in mandibular molars.

Giant schwannoma of thoracic vertebra: A case report.

BACKGROUND: It is relatively rare for schwannomas to invade bone, but it is very rare for a large mass to form concurrently in the paravertebral region. Surgical resection is the only effective treatment. Because of the extensive tumor involvement and the many important surrounding structures, the tumor needs to be fully exposed. Most of the tumors are completely removed by posterior combined open-heart surgery to relieve spinal cord compression, restore the stability of the spine and maximize the recovery of nerve and spinal cord function. The main objective of this article is to present a schwannoma that had invaded the T5 and T6 vertebral bodies and formed a large paravertebral mass with simultaneous invasion of the spinal canal and compression of the spinal cord. CASE SUMMARY: A 40-year-old female suffered from intermittent chest and back pain for 8 years. Computed tomography and magnetic resonance imaging scans showed a paravertebral tumor of approximately 86 mm × 109 mm × 116 mm, where the adjacent T5 and T6 vertebral bodies were invaded by the tumor, the right intervertebral foramen was enlarged, and the tumor had invaded the spinal canal to compress the thoracic medulla. The preoperative puncture biopsy diagnosed a benign schwannoma. Complete resection of the tumor was achieved by a two-step operation. In the first step, the thoracic surgeon adopted a lateral approach to separate the thoracic tumor from the lung. In the second step, a spine surgeon performed a posterior midline approach to dissect the tumor from the vertebral junction through removal of the tumor from the posterior side and further resection of the entire T5 and T6 vertebral bodies. The large bone defect was reconstructed with titanium mesh, and the posterior root arch was nail-fixed. Due to the large amount of intraoperative bleeding, we performed tumor angioembolization before surgery to reduce and avoid large intraoperative bleeding. The postoperative diagnosis of benign schwannoma was confirmed by histochemical examination. There was no sign of tumor recurrence or spinal instability during the 2-year follow-up. CONCLUSION: Giant schwannoma is uncommon. In this case, a complete surgical resection of a giant thoracic nerve sheath tumor that invaded part of the vertebral body and compressed the spinal cord was safe and effective.

Sequential release of immunomodulatory cytokines binding on nano-hydroxyapatite coated titanium surface for regulating macrophage polarization and bone regeneration.

Inflammation occurs when the material is implanted into the body. As one of the important immune cells in the regulation of inflammation, macrophages are able to remove pathogens and necrotic cells, and polarize to different phenotypes to regulate inflammatory response for tissue regeneration. Therefore, it is known that the sequential release of immunomodulatory cytokines from the surface of titanium (Ti) implants can regulate the polarization of macrophages and promote osseointegration of implants. In order to control the switch of macrophage phenotypes at desired time, we fabricated hydroxyapatite (HAp) nanotube arrays coating on Ti surface, by acid-etching, alkali-heating and HAp coating sequentially. Then we loaded the interleukin-4 (IL-4) encapsulated by poly (lactic-co-glycolic acid) (PLGA) on the bottom of the nanotube and the interferon-γ (IFN-γ) encapsulated by sodium hyaluronate (SH) on the top of the nanotube. Based on the physical and chemical properties of PLGA and SH and the spatial distribution of loaded cytokines, we hypothesized that the programmed release of IFN-γ and IL-4, which made the phenotypic transition of macrophages at a specific time, so as to regulate inflammation and promote osteogenic repair. Our hypothesis created a new type of drug sustained release system, which has high research value for improving the osseointegration of implants.

[Mechanical properties of 3D-printed titanium mesh and its biocompatibility in vitro].

PURPOSE: To compare the mechanical properties of 3D-printed titanium meshes and pre-shaped titanium meshes, and to evaluate the effects of 3D-printed titanium meshes on cell proliferation and differentiation. METHODS: 3D- printed titanium meshes were produced and prepared with laser printing machine. The mechanical properties were analyzed by static tension and compression load test. Bone marrow mesenchymal stem cells (BMSCs) were extracted from 4-week-old male SD rats. BMSCs were co-cultured with 3D-printed titanium meshes of different apertures. Cell counting kit-8 (CCK-8) assay was used to detect cell proliferation. Alkaline phosphatase (ALP) activity assay was used to test ALP activity. The expression of related osteogenic genes was tested by real-time PCR. The adhesion and growth of BMSCs were investigated by scanning electron microscopy (SEM) and living / dead cell staining. SPSS 22.0 software package was used for statistical analysis of the results. RESULTS: The results of 3D-printing Ti-meshes tension and compression loading experiment were excellent. The 3D-printing Ti-meshes showed no inhibitory effects on cell proliferation, survival and adhesion, but had a positive effect on osteogenesis of BMSCs. CONCLUSIONS: The mechanical properties of 3D-printed Ti-meshes are excellent. The 3D-printed Ti-meshes have good biocompatibility.

Changes of the condylar position after modified disk repositioning: A retrospective study based on magnetic resonance imaging.

OBJECTIVE: This study aimed to explain the malocclusion resulting from the changes in condylar position after unilateral open disk repositioning surgery. STUDY DESIGN: Patients treated with unilaterally modified temporomandibular joint disk repositioning were reviewed. All patients underwent magnetic resonance imaging (MRI) before and immediately after surgery. Occlusion was checked, and the changes in the joint space and condylar position were measured by using MRI. The paired t test was used for analysis. RESULTS: Thirty-two patients were included in the final analysis. The incidence rates of the posterior open bite in the affected side were 100%, 87.5%, 71.9%, 9.4%, 3.1%, and 3.1% at 0, 3, and 7 days and 3 and 6 months, and at the last follow-up after surgery, respectively. Mean distances of the condylar movements were 2.67 and 0.32 mm in the affected joints and normal joints, respectively. There were significant differences for the anterior (P = .03), superior (P < .001), and posterior (P < .001) joint spaces of the affected joints as demonstrated by MRI. CONCLUSIONS: The joint spaces significantly increased postoperatively, in addition to the changes in condylar position in anterior and inferior movements, leading to posterior open bite; however, the position returns to normal 3 months after surgery. We concluded that disk repositioning, when done unilaterally, results in stable occlusion over time.

Chitosan oligosaccharide inhibits skull resorption induced by lipopolysaccharides in mice.

BACKGROUND: Low-molecular-weight chitosan oligosaccharide (LMCOS), a chitosan degradation product, is water-soluble and easily absorbable, rendering it a popular biomaterial to study. However, its effect on bone remodelling remains unknown. Therefore, we evaluated the effect of LMCOS on lipopolysaccharide (LPS)-induced bone resorption in mice. METHODS: Six-week-old male C57BL/6 mice (n = five per group) were randomly divided into five groups: PBS, LPS, LPS + 0.005% LMCOS, LPS + 0.05% LMCOS, and LPS + 0.5% LMCOS. Then, the corresponding reagents (300 µL) were injected into the skull of the mice. To induce bone resorption, LPS was administered at 10 mg/kg per injection. The mice were injected three times a week with PBS alone or LPS without or with LMCOS and sacrificed 2 weeks later. The skull was removed for micro-computed tomography, haematoxylin-eosin staining, and tartrate-resistant acid phosphatase staining. The area of bone damage and osteoclast formation were evaluated and recorded. RESULTS: LMCOS treatment during LPS-induced skull resorption led to a notable reduction in the area of bone destruction; we observed a dose-dependent decrease in the area of bone destruction and number of osteoclasts with increasing LMCOS concentration. CONCLUSIONS: Our findings showed that LMCOS could inhibit skull bone damage induced by LPS in mice, further research to investigate its therapeutic potential for treating osteolytic diseases is required.

The effect of vascular endothelial growth factor (VEGF) on mouse condylar articular cartilage cultured in vitro.

In this study, we explored the direct effect of vascular endothelial growth factor (VEGF) on temporomandibular joint osteoarthritis (TMJ-OA) by analyzing the transformation of mouse condylar cartilage treated in vitro with various concentrations of VEGF. Tissue samples from 126 condyles of four-week-old male C57 mice were randomly divided into 21 groups and treated with VEGF (0 ng/mL, 100 ng/mL, 500 ng/mL, 1 µg/mL, or 2 µg/mL). Furthermore, the samples were treated at different time points (1 d, 2 d, 4 d, and 7 d) and stained with hematoxylin and eosin (HE) and Safranin O and Fast Green stains to observe their morphology. The Mankin score was used to evaluate changes to the condylar cartilage tissues, and immunohistochemistry was performed to observe the expressions of VEGF receptor 2 (VEGFR2), matrix metallopeptidase 9 (MMP9), matrix metallopeptidase 13 (MMP13), and tumor necrosis factor-related activation-induced cytokine (TRANCE). An HE staining analysis revealed that the experimental groups treated with VEGF exhibited the destruction of their condylar cartilage and a proliferation of their hypertrophic cells, in comparison to the control group. Safranin O and Fast Green staining showed that the experimental groups had decreased levels of proteoglycan and degenerative changes in their condylar cartilage. The Mankin score of the samples increased with increasing concentration and treatment time of VEGF, and the differences between the groups were statistically significant (P < 0.05). Immunohistochemistry demonstrated that the expression levels of VEGFR2, MMP9, MMP13, and TRANCE significantly increased in the experimental groups, in comparison to those in the control group, suggesting that VEGF promoted TMJ-OA in mice in vitro.

[Review and prospectives of oral-maxillofacial surgery in the world].

This article introduced the developing history and present status of oral and maxillofacial surgery in the world, with the aim to provide references for education of oral and maxillofacial surgery and further development.

A Novel Surgical Technique for Augmented Corticotomy-Assisted Orthodontics: Bone Grafting With Periosteum.

PURPOSE: To introduce grafting fixed with the periosteum (dumpling technique) as an alternative surgical technique for augmented corticotomy-assisted orthodontics in the lower anterior region and evaluate the preliminary outcomes. MATERIALS AND METHODS: Eleven patients (9 women, 2 men; mean age, 21.4 yr) with a thin alveolus or alveolar defect in the lower anterior region by clinical and radiographic examination underwent an augmented corticotomy using the new dumpling technique. Cone-beam computerized tomography was used to evaluate morphologic changes of the lower anterior ridge before treatment (T0) and 1 week (T1) and 6 months (T2) after the bone-augmentation procedure. Repeated-measures analysis of variance with Bonferroni multiple-comparison test was used to compare variables at each time point. RESULTS: No severe postsurgical complications occurred in any patient. The mean alveolar bone thickness of the labial plate increased from T0 to T1 (P < .001) and decreased from T1 to T2 (P < .001). However, compared with T0, there was still a significant increase in horizontal bone thickness at T2 (P < .05). The vertical alveolar bone level increased from T0 to T1 (P < .001) and was maintained from T1 to T2 (P > .05). No significant differences were found in root length of the lower anterior teeth at these 3 time points (P > .05). CONCLUSIONS: In this preliminary study, the dumpling technique for augmented corticotomy-assisted surgical orthodontics showed alveolar bone augmentation by increasing the vertical alveolar height and the horizontal bone thickness in the labial aspect of the anterior mandibular area. However, long-term follow-up is necessary.

Case studies on local orthodontic traction by minis-implants before implant rehabilitation.

OBJECTIVE: Dentition defect with malocclusion is a common occurrence in the clinical work. To restore proper occlusion, preprosthetic corrections of these malposed teeth are often indispensible. The use of orthodontic mini-implants as temporary anchorage devices provides a plausible treatment for those patients with local problems. The aim of this study was to present two cases using local orthodontic traction in conjunction with mini-implants to provide necessary conditions for implant rehabilitation in three dimensional space. Clinical consideration: Two cases who had dentition defect with malocclusion were included in the present study. As both of them rejected crown reduction or orthodontics treatment, local orthodontic traction by mini-implants was used to restore normal space for implant rehabilitation in three dimensions. Careful mechanics analysis and personalized mechanical device were under consideration. The results showed that the biological responses of the corrected teeth and the surrounding bony structures appeared normal and acceptable. Moreover the patients achieved an ideal local occlusion with a short treatment time. CONCLUSION: In conclusion local orthodontic traction by mini-implants was a less-invasive and short-term method with favorable effects and less necessary occlusal adjustments.

Stability study of total temporomandibular joint replacement on sheep.

OBJECTIVE: To evaluate the stability of our custom-made prosthesis by establishing the model of sheep total temporomandibular joint (TMJ) replacement. METHODS: Six sheep were included in our study. Spiral computed tomography (CT) data of all sheep was obtained and transformed into 3-dimensional model by surgicase5.0 software preoperatively. Total TMJ prostheses were made based on the skull model. Ultra-high molecular weight polyethylene was used to make glenoid fossa lining, while titanium alloy to prefabricate mandibular retention handle and titanium plate over glenoid fossa. Cobalt-chromium-molybdenum alloy was also used to prefabricate the condyle. The right sides of all sheep, as the experimental group, were carried out total TMJ replacement, while the left sides were as the control group. The bone in both experimental and control side were excised after 3 and 6 months. Scanning electron microscope (SEM) was used to observe the interface between bone and prosthesis. Van Gieson staining and immunohistochemical staining (IHC) were used respectively to observe the interface of titanium screw and bone and the expression of alkaline phosphatase (ALP). RESULTS: SEM and Van Gieson staining showed that there was immature bone and osteoid formed in the interface of prosthesis and bone after 3 months. While after 6 months, there was osseointegration between them. IHC showed that the expression of ALP in the experimental side was much higher than in the control side after 3 months and its expression decreased after 6 months with no difference from the control side. CONCLUSION: The custom-made TMJ prosthesis which was designed and manufactured by ourselves has good stability after total TMJ replacement.

[Comparison of dental education between 3 schools of dentistry in Europe, America and China].

In order to understand the status and characteristics of dental education in Europe, America and China, and clarify the shortcomings of dental education in China, this study selected Columbia University, Vienna Medical University and Shanghai Jiao Tong University College of Stomatology as representatives. The similarities and differences of the three institutions were compared through investigating education background and education model, in order to provide references for dental education. Supported by Medical Education Research Projects of Shanghai Jiao Tong University College of Stomatology(YB120913).

Magnetic resonance imaging applied to the diagnosis of perforation of the temporomandibular joint.

OBJECTIVE: To investigate the diagnostic accuracy of magnetic resonance imaging (MRI) for perforation of temporomandibular joint (TMJ). METHODS: Consecutive 1845 patients (2524 joints) diagnosed as internal derangement (ID) of TMJ were collected from April 2003 to March 2010 in our department. All the patients were examined by MRI and treated by arthroscopy or open surgeries. The findings of interpreting MRI were recorded as positive, suspicious and negative according to the MRI radiographic criteria. After comparing the findings of MRI with those of arthroscopy or open surgeries, the numbers of true positive, true negative, false positive and false negative were obtained. Through SPSS16.0, receiver operator characteristic curve (ROC curve) was made with 1-specificity as abscissa and the sensitivity as ordinate, and the area under the ROC curve was calculated. According to the area, the diagnostic value of MRI was evaluated. RESULTS: Arthroscopic or open surgeries findings confirmed that 207 joints had disc perforation among all joints. MRI findings showed 189 joints were positive, 197 joints suspicious, and 2138 joints negative. The true positive accuracy of MRI findings was 102/189 while true negative accuracy was 2075/2138. 42 of the 197 suspicious joints had perforation. The area under the ROC curve was 0.808 (0.77, 0.85), P < 0.05. CONCLUSION: We concluded that MRI proved to be a good modality to diagnose disc perforation of TMJ, and the diagnostic result of disc perforation by MRI had certain guiding significance in our clinical work.

Can puncture increase the risk of intra-articular adhesion in the temporomandibular joint?

PURPOSE: This study aims to compare the incidence and severity of intra-articular adhesion under arthroscopy between patients with and without a history of joint puncture. PATIENTS AND METHODS: Eighty-nine patients with internal derangements of TMJ who underwent arthroscopic disc repositioning and suturing surgery from February 2008 to September 2008 were included in this study. Patients were divided into 2 groups based on whether the patient had undergone joint puncture before surgery or not. The diagnosis of intra-articular adhesion was made according to the manifestation under arthroscopy. Incidence and severity of intra-articular adhesion between these 2 groups was compared. RESULTS: The incidence of intra-articular adhesion in the patients with a history of puncture was 69.23%, which was higher than that in the patients without a history of puncture (24.36%). The difference was statistically significant (P < 0.05). The incidence of severe adhesions in patients with a history of joint puncture was also higher than that in patients without a history of puncture (26.09% vs. 2.56%, P < 0.01). CONCLUSIONS: Puncture may increase the risk of intra-articular adhesion in patients with internal derangement.

Current undergraduate and postgraduate dental education in China.

China is a developing country with the largest population of any country in the world. The 2010 sixth national census found that China's population was 1,339,724,852, accounting for about 19 percent of the world's total population. However, higher education in the Chinese dental field started late and developed slowly. In order to acquaint more dental educators worldwide about China's current higher dental education system, this article provides a brief introduction to the present education system, degrees conferred, curriculum setting, training mode, teaching materials, courses, and academic journals.

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.

Case-based learning in clinical courses in a Chinese college of stomatology.

As a medical approach to posing contextualized questions that are based on real-life clinical problems, case-based learning (CBL) is used to stimulate and underpin the acquisition of knowledge, skills, and attitudes through clinical cases. Good effects were acquired in the practice of CBL teaching in English applied by the College of Stomatology, Shanghai Jiao Tong University. Responses from both students and teachers reflected that this course approach won their high acceptance and was worthy of use in selected stomatological courses.

Creating an effective PBL case in oral and maxillofacial surgery at a Chinese dental school: a dental education primer.

Problem-based learning (PBL) is a widely accepted educational method centered on the discussion and learning that emerge from a clinically based problem; however, little has been reported on the details of PBL case-writing in the dental education literature. This article outlines some principles of writing a PBL case as it is practiced at a Chinese dental school and presents, as an example, an actual case based on a clinical problem (ameloblastoma of the jaw) intended to provide a learning focus for predoctoral dental students. A good PBL case should allow for progressive, interdependent actions to be taken in the evaluation and overall management of the patient in context and should trigger inquiry and discussion among students in both the basic sciences (anatomy, physiology, biochemistry, pharmacology, pathophysiology, etc.) and related clinical sciences. The epidemiological, sociological, and ethical considerations related to each problem should also be emphasized as an essential component of effective health care provision.