The use of traditional finite element method (FEM) in occlusal stress analysis is limited due to the complexity of musculature simulation. The present purpose was to develop a displacement boundary condition (DBC)-FEM, which evaded the muscle factor, to predict the dynamic occlusal stress. The geometry of the DBC-FEM was developed based on the scanned plastic casts obtained from a volunteer. The electrognathographic and video recorded jaw positional messages were adopted to analyze the dynamic occlusal stress. The volunteer exhibited asymmetrical lateral movements, so that the occlusal stress was further analyzed by using the parameters obtained from the right-side eccentric movement, which was 6.9 mm long, in the stress task of the left-side eccentric movement, which was 4.1 mm long. Further, virtual occlusion modification was performed by using the carving tool software aiming to improve the occlusal morphology at the loading sites. T-Scan Occlusal System was used as a control of the in vivo detection for the location and strength of the occlusal contacts. Data obtained from the calculation using the present developed DBC-FEM indicated that the stress distribution on the dental surface changed dynamically with the occlusal contacts. Consistent with the T-Scan recordings, the right-side molars always showed contacts and higher levels of stress. Replacing the left-side eccentric movement trace by the right-side one enhanced the simulated stress on the right-side molars while modification of the right-side molars reduced the simulated stress. The present DBC-FEM offers a creative approach for pragmatic occlusion stress prediction.

Objective:To describe and analyze the clinical manifestations of patients with orofacial pain of temporomandibular disorders (TMD).Methods:A retrospective study on orofacial pain was conducted for 3 425 patients diagnosed as TMD based on clinical symptoms and signs in the Department of Temporomandibular Disorders and Orofacial Pain, School of Stomatology, The Fourth Military Medical University. The patients included 1 158 males and 2 267 females with a median age of 32 years. The gender, age, course of disorders, pattern and site of pain, CT imaging diagnosis of temporomandibular joint (TMJ) were analyzed. The distribution of gender, age and disorder course interval were described. The differences in frequency of the pattern and site of pain, imaging diagnosis in different gender, age and disease course interval were compared. Chi-square test and non-parametric rank sum test were performed using software SPSS 23.0.Results:Of the 3 425 patients, 29.1% (997/3 245) had signs of joint popping, and 40.1% (1 373/3 425) had restricted opening. The pain frequency was higher in males who had disorder course less than 1 month ( P<0.01) and also in males who had open-and-close and/or lateral excursion and/or protrusion pain without tenderness or other pain without tenderness ( P<0.05). However, the pain frequency was higher in females who had tenderness ( P<0.01). The pain frequencies in those over 56 years old with tenderness combined with open-and-close and/or lateral excursion and/or protrusion pain were higher than in patients of other ages ( P<0.01). In patients with unilateral TMJ pain, the frequency in males was higher than females( P<0.01), while the frequency in females was higher in patients with unilateral TMJ pain combined with unilateral or bilateral myalgia and the frequency was higher in patients under 15 years old having bilateral TMJ pain and/or unilateral or bilateral myalgia ( P<0.05). In patients with unilateral TMJ pain, the frequency in those with disorder course≤1 month was higher than in those with other disease duration intervals ( P<0.01), while in patients with bilateral myalgia or TMJ pain plus unilateral or bilateral myalgia, the frequency in those with disorder course>3 years was higher than in those with other disease duration intervals( P<0.01). In patients with unilateral TMJ pain, the frequency was higher in those having open-and-close and/or lateral excursion and/or protrusion pain ( P<0.01). In patients with unilateral myalgia and bilateral myalgia, the frequency was higher in those having tenderness ( P<0.01). The frequency of TMJ space changes in male patients was higher than females and the frequency of hyperosteogeny and resorption in females were higher than males ( P<0.05). The frequency of TMJ space changes and developmental problems were higher in patients aged 16 to 35 years, while the frequencies of hyperosteogeny, bone resorption and cystis in those over 56 years were higher than other ages ( P<0.01). The frequency of TMJ space changes in patients with disorder course≤1 month was higher than in those with other disease duration intervals ( P<0.01), while the frequency of hyperosteogeny was higher in patients with disorder course>3 years ( P<0.01). Conclusions:The male to female ratio in the present patients with orofacial pain of TMD was about 1 to 2. Most of the patients visited hospital within half a year after the disorders occurred. The pattern and site of the orofacial pain, signs on TMJ CT images showed some distribution regularities in views of gender, age and disorder course.

Objective:To analyze the dental and mandibular asymmetry of adults with Class Ⅱ subdivision malocclusion.Methods:The jaw bones of 30 adults with Class Ⅱ subdivision malocclusion(case group)and 30 with normal-occlusion(control group)were scanned by CBCT.Linear and angular comparison was conducted between the two groups.Results:Dental midline deviation was ob-served in case group,mostly in mandibular arch (60%).The development of Class Ⅱ molar relationship correlated mainly to distally positioned mandibular molar on Class Ⅱ side.Conclusion:In the adults with Class Ⅱ subdvision malocclusion odontogenic asymme-try is the major factor,bony asymmetry is the miner.

Objective:To study the influence factors of laser therapy in the treatment of temporomandibular disorders(TMD)pain. Methods:1 20 cases of TMD were treated by MDC-500 semiconductor laser therapy.VAS was valued after each treatment.The cor-relation of the VAS varians following treatment with gender and age was analysed by two way AHOVA of the repeated measurement data.Results:1 1 4 cases completed the treatment and follow-up.After each treatment the VAS decreased(P <0.001 ),in females decreased more than in males(P <0.05).There was no significant difference between age groups(P =0.208).Conclusion:Laser therapy can ease TMD pain,and is more effective for female patients.

Objective:To analyse the asymmetry of mandibular of adults with skeletal classⅢmalocclusion and mandibular deviation using cone-beam computerized tomography(CBCT).Methods:20 adults with skeletal classⅢmalocclusion and mandibular deviation (deviation group)and 20 adults with individual normal occlusion(normal group)were included.CBCT slices were taken for each sub-ject.INVIVO 5 software was used to make 3D reconstruction and location marks for line distance and volume measurements of mandi-ble and condyle.Results:The measurements of the mandibular ramus length,mandibular total length,hemi-mandibular volume, mandibular ramus volume,posterior part of mandibular body length,condylar unit length,angular unit length,body unit length and an-gular angle in deviation group were significantly different between 2 sides(P<0.05).Compared with the normal group,differences of the asymmetry of mandibular ramus length,mandibular total length,hemi-mandibular volume,mandibular ramus volume,posterior part of mandibular body length,angular angle,condylar unit length and body unit length between 2 sides in deviation group were sig-nificantly different(P<0.05).Conclusion:In adults with skeletal classⅢmalocclusion and mandibular deviation deviated condylar and mandibular ramus are smaller than those of the nondeviated;the posterior part of mandibular body is slightly asymmetric while the anterior part of mandibular body is almost symmetric.

Objective To compare the ultra-microscopic changes of periodontal Ruffini's corpuscle induced by different patterns of tooth movement,and investigate the influence of different changes of the periodontal mechanical environment on the periodontal mechanoreceptor.Methods Thirty-two eight-weeks-old SD rats were divided into control group(n=4),none-extraction group(n=12) and extraction group(n=12),and none-extraction group and extraction group were further divided into three subgroups,namely 3 day and 14 day and 28 day.For control group,no intervention was performed.For none-extraction group and extraction group,the following interventions were conducted.In none-extraction group,the maxillary left and mandibular right third molars were moved distally.In extraction group,the maxillary left third molar was moved distally,and the bilateral mandibular third molars were extracted.The ultra-structures of periodontal Ruffini's corpuscle in the periodontal ligament of the distal root of the bilateral maxillary third molars were observed under the transmission electron microscope.Results The ultra-structrural changes in the none-extraction group were mainly characterized by degeneration or abnormal distribution of mitochondria in the axon terminal,which were almost recovered at 28 d.In the extraction group,the changes were mainly characterized by deficiency or abnormal elongation of the Schwann sheath and were not recovered at 28 d.Conclusions The ultra-structures of periodontal Ruffini's corpuscle might be influenced by tooth movement and occlusal changes,and the mechanorecepting function of it might be affected by changes of the periodontal mechanical environment.

OBJECTIVETo study the effects of experimentally created unilateral anterior crossbite prosthesis on the expression of parathyroid hormone-related peptide (PTHrP) and parathyroid hormone receptor-1 (PTH1R) in mandibular condylar cartilage of SD rat.

METHODSIn experimental groups, the unilateral anterior crossbite metal prosthesis was cemented to the left incisors of the maxilla and mandible of 6-week-old SD rats, respectively. Animals were sacrificed at 2, 4, 8 weeks. Hematoxylin-eosin (HE) staining were carried out for studying the morphological changes of the condylar cartilage. Immunohistochemical staining and real-time polymerase chain reaction (PCR) analysis were performed to detect the levels of expression of PTHrP and PTH1R in the condylar cartilages.

RESULTSThe obvious degenerative changes were found in the condylar cartilages in experimental group at 8 weeks. Comparing to the control group, the expression of PTHrP mRNA (P < 0.01) and protein(P < 0.01) in the experimental group were increased, whereas PTH1R mRNA (P < 0.01) and protein (P < 0.01) levels were decreased.

CONCLUSIONThe expression of PTHrP was increased in the condylar cartilage of rat with unilateral anterior crossbite metal prosthesis but its effects might be limited because of decreased expression of PTH1R in the condylar cartilage. The low level expression of PTH1R should be a part of the constitution of the molecular pathomechanism of temporomandibular joint osteoarthritis (TMJOA)-like lesion.

Animals ; Cartilage ; Cartilage, Articular ; Incisor ; Malocclusion ; Mandible ; Mandibular Condyle ; Osteoarthritis ; Parathyroid Hormone-Related Protein ; Prostheses and Implants ; Rats ; Rats, Sprague-Dawley ; Receptor, Parathyroid Hormone, Type 1 ; Temporomandibular Joint

Purpose　The aim is to establish a simple method to extract superoxide dismutase(SOD) from pig blood red cells.Methods　A combined method-microwave heating and adding Cu2+ into the suspension-was used to extract SOD from the red cells. Results　The undesired proteins were denatured by microwave heating and SOD was partly purificated in comparison with hemolysis. The processing time of the former was much shorter than the latter. Conclusion　A novel cell disruption microwave heating, was a rapid and effective technique for the primary extraction of SOD.

Objective:To investigate the role of pleiotrophin (PTN) gene in carcino genesis using cDNA microarray and in situ hybridization. Methods:The expression of PTN gene in 5 cases of glioma, 10 laryngeal squamous cell carcinoma, 6 cases of hepatocarcinoma, and normal controls were detected by BioDoor 4096 type cDNA microarray and in situ hybridization. Results: The expression of PTN gene in carcinoma samples were significantly higher than in normal controls by cDNA microarray, the results was the same as by in situ hybridization. Conclusion: cDNA microarray is an effective technique in analysis of functional study of associated genes in carcinoma. High expression of PTN gene might be correlated with mechanism of multiple carcinoma. [

Objective: : To observe whether cytokines rIL 2,TNF ?,I FN ? and anti CD3/anti glioma bispecific antibody(BsAb) can work coordinately, and to investigate how to further enhance cytotoxicity of T lymphocyte against human glioma cells by BsAb. Methods: There were 12 groups,contr ast method were used to analyze the effect of cytokines rIL 2,TNF ?,IFN ? to cytoxicity directed by BsAb by single and combined experiments. Cytotoxicity was assayed by standard 18 h 3H TdR incorporation release. Resul ts: rIL 2,TNF ?,IFN ? and BsAb could cooperatively enhance the cy totoxicity of effect cells( P