Adaptive remodeling of temporomandibular joint following anterior disc displacement and treatment decision making / 中华口腔医学杂志

Anterior disc displacement (ADD) of temporomandibular joint (TMJ) is one of the common oral diseases. The TMJ can be remodeled after disc displacement. The author's recent studies show that remodeled bilaminar zone is similar to the disc in composition and functions. The remodeled condyle can match the disc-like bilaminar zone. The new disc-condylar relationship can, to a certain extent, restore the function of the TMJ. Based on these studies, the author believes that the adaptive remodeling in TMJ has important guiding significance for clinical treatment and discusses the views of the treatment decision for various stages of temporomandibular disorders.

Research on condylar morphology in patients with prolonged unilateral posterior teeth loss with cone beam computed tomography / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed at using cone beam computed tomography (CBCT) to study the influence ofprolonged unilateral posterior teeth loss on bilateral condylar morphology.</p><p><b>METHODS</b>The CBCT images of 30 patients withprolonged unilateral posterior teeth loss and 30 healthy people as controls were corrected. Mimics 15.0 software was used tomeasure volume, area, distance, and bone density of condyle. The results were statistically analyzed.</p><p><b>RESULTS</b>The volumeand bone density of condylar head and the entire condyle on missing teeth side were less than the contralateral side (P<0.05).The area and bone density of condylar transverse plane were greater than the contralateral side (P<0.05).</p><p><b>CONCLUSION</b>After prolonged unilateral posterior teeth loss, adaptive reconstruction occurs in the bilateral condyles, and condyle of missing teethside is smaller than the contralateral side.</p>

Involvement of Smad pathway in proteoglycan 4 expression induced by hydrostatic pressure in temporomandibular synovial fibroblasts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To examine the expression of proteoglycan 4 (PRG-4) induced by hydrostatic pressure in rat temporomandibular synovial fibroblasts and investigate the possible mechanism.</p><p><b>METHODS</b>The cultured rat temporomandibular synovial fibroblasts were subjected to 100 kPa magnitude intermittent hydrostatic pressure (IHP) at frequency of 4 h/day, and the static group served as control. The expressions of Smad pathway proteins and p38MAPK pathway proteins were analyzed by Western blot and immunofluorescence staining. Then the cells were incubated with SB431542, the inhibitor of transforming growth factor (TGF)-β receptor. Western blot and reverse transcription PCR were used to detect the PRG-4 expression after 72 h.</p><p><b>RESULTS</b>The expression of phosphorylated Smad-2 and phosphorylated Smad-3 were increased after 1 h of IHP, reaching a maximum after 2 h and 4 h of IHP, respectively.However, the protein content of phosphorylated p38 did not vary significantly. In addition, IHP induced nuclear translocation of Smad-2/-3, and the immunofluorescence staining signal intensity markedly increased (24.11 ± 4.70)(P < 0.05). The levels of PRG-4 mRNA were significantly increased by IHP (1.48 ± 0.08)(P < 0.05). Treatment of cells with SB431542 could decrease the expression of PRG-4 mRNA significantly after IHP (0.47 ± 0.05)(P < 0.05). In addition, SB431542 inhibited the expression of PRG-4 protein induced by IHP.</p><p><b>CONCLUSIONS</b>Smad signal acts as an essential signal pathway to regulate PRG-4 expression induced by IHP.</p>

Research progress on root canal biofilm / 实用口腔医学杂志

Root canal biofilm is frequently detected in the canal wall of infected root canal and the root canal with failed root canal therapy. Due to its special structure and diverse composition, root canal biofilm has the ability of the drug tolerance and antiimmunity, which lead to apical periodontitis. This review summarizes the features of the root canal biofilm and latest clinical methods to remove it.

Progress and prospect in the research of bone morphogenetic protein heterodimer / 生物医学工程学杂志

Bone morphogenetic protein (BMP) homodimers are of significant osteoinductivity. However, their clinical application is limited because of high effective dosage. Recently, BMP heterodimers are reported to address the issue. This is a review of the researches on BMP heterodimers, including existent evidences, types and synthetic methods, biological activities in comparison to BMP homodimers and possible mechanisms, further research direction and future expectations.

Expression of fibroblast growth factor receptor 3 in odontogenic tumor / 中国组织工程研究

BACKGROUND:The relationship of fibroblast growth factor receptor 3 (FBGFR3) and malignant tumor has been confirmed. However, domestic and foreign studies on whether FBGFR-3 plays a role in odontogenic tumor with special biological characteristic are few.OBJECTIVE: To observe the expression of FBGFR-3 in odontogenic tumor.DESIGN: A randomized controlled observation.SETTING: Department of Stomatology, Medical College, Medical College of Huzhou Teachers College; Stomatology Hospital Affiliated to Zhejiang University.MATERIALS:This experiment was carried out in the Stomatology Hospital, Medical College Affiliated to Zhejiang University between January 2003 and December 2004.All the samples were from the odontogenic tumor patients admitted to Department of Pathology, Stomatology Hospital Affiliated to Medical College of Zhejiang University between year 1999 and year 2000, including 29 patients with ameloblastoma, 20 keratocyst and 36 primordial cyst. Normal dental crypt or residual dental lamina epithelium tissue served as control. All the samples were embedded by paraffin, sliced into 3 to 5 μm-thickness sections, placed on polylysine-spread slide, and dried for later use.METHODS: The expressions of FBGFR-3 in the normal dental crypt or residual dental lamina epithelium tissue,odontogenic ameloblastoma, keratocyst and primordial cyst were detected by immunohistochemical method.MAIN OUTCOME MEASURES: Expressions of FBGFR-3 in ameloblastoma, keratocyst and primordial cyst.RESULTS: The expression of FBGFR-3 in the ameloblastoma, keratocyst and primordial cyst was positive, presenting 59%, 45% and 8%, respectively, and there were significant differences in expression of FBGFR-3 among these three;FGGFR-3 was not expressed in the normal dental crypt and residual dental lamina epithelium tissue. FBGFR-3-positive cells gathered in the maturation region of tumor cells.CONCLUSION: FBGFR-3 may be related to the pathogenesis of ameloblastoma and keratocyst, and terminal differentiation mechanism.

Progress in Researches of Eph/ephrin Signaling in Coupling of Bone Resorption and Bone Formation / 生物化学与生物物理进展

Osteoclastic bone resorption and osteoblastic bone formation are coordinated as a coupled mechanism to effect the development of bone and to maintain bone homeostasis. Recently reported Eph/ephrin bidirectional signaling between osteoclasts and osteoblasts plays a pivol role in bone homeostasis and casts new light on coupling of bone resorption and bone formation, which is gaining more and more attention in researches of bone biology and bone diseases. The present article aims to address the researches on the Eph/ephrin bidirectional signaling between osteoblasts and osteoclasts with molecular constitution, mechanism of the signal transduction, biological significance and so on.

Chondrocyte apoptosis in rabbit temporomandibular joint after anterior disc displacement / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the chondrocyte apoptosis in rabbit temporomandibular joint after anterior disc displacement.</p><p><b>METHODS</b>Experimental anterior disc displacement was induced surgically in 20 Japanese rabbits without opening their temporomandibular joint bursas. Histopathologic and apoptotic (TUNEL) analysis was used to evaluate the changes in articular cartilage, disc and synovium.</p><p><b>RESULTS</b>Condyle chondrocyte showed apoptosis most obviously at 1 or 2 weeks after surgery, and apoptotic cells concentrated in proliferative zone and hypertrophic zone. 4 or 6 weeks after surgery, the joint went into a remodelling period.</p><p><b>CONCLUSIONS</b>Chondrocyte apoptosis in temporomandibular joint will be activated after anterior disc displacement, which initiates the remodelling in temporomandibular joint.</p>

Adaptive alterations of elastic fibers in the bilaminar zone of rabbit temporomandibular joint following disc displacement / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To study the adaptive alterations of elastic fibers in the bilaminar zone (BZ) of rabbit temporomandibular joint (TMJ) following disc displacement.</p><p><b>METHODS</b>Twenty-eight Japanese white rabbits were used in this study. The right temporomandibular joints of 20 of 28 rabbits were subjected to the surgical procedure of anterior disc displacement (ADD). Four rabbits in the surgical group were sacrificed at 2, 4, 6, 8 and 12 weeks after operation. Their temporomandibular joints were studied histochemically.</p><p><b>RESULTS</b>Elastic fibers were reduced in number and ran irregularly in the superior lamina of BZ from ADD rabbits. The jungly elastic fibers (EFs) could still be seen at 2 weeks after operation. At 4 weeks, the number of EFs decreased significantly; EFs lost their jungly arrangement and were shaped like rough dots, of which the arrangement and the lengths were different. Six weeks after operation, many EFs were replaced by distorted, uneven, non-oriented fine EFs, distributed unevenly and some thick or fine EFs that ran irregularly. The number of EFs decreased further and their arrangement was more deranged at 8 weeks. At 10 and 12 weeks, EFs in the superior lamina of BZ were similar to those at 8 weeks.</p><p><b>CONCLUSION</b>Our results show that EFs lost their function as well as their distribution and arrangement after disc displacement.</p>

Temporomandibular joint function disturbance after mandibular fracture / 实用口腔医学杂志

Objective: To study temporomandibular joint function after mandibular fracture. Methods: According to the methods of Helkimo, the questionnaire and clinical examination were administered in 36 cases with mandibular fracture and 32 health controls. Results:There were statistically significant difference between the fracture group and control group in anamnestic dysfunction and clinical dysfunction index(P0.05).Conclusion: People with mandibular fracture have more symptoms and sign of temporomandibular dysfunction in the time ranged.

The computer-assistant study of the relationship between orthodontic treatment and temporomandibular joint disorders / 实用口腔医学杂志

Objective: To study the relationship between orthodonti c treatment and temporomandibular joint disorders(TMD). Methods: The survey tables and their corresponding database were designed with the aid of computer. The questionnaire and clinical examination were administered t o 173 cases who had received orthodontic treatment (orthodontic group), 95 case s with morphologic malocclusion and without having orthodontic treatment ( maloc clusion group) and 32 cases with normal occlusion (normal group).Symptoms and s igns of TMD were collected,the data were analyzed with the databases. Results: The survey tables and their corresponding database were se t up. There were statistically significant differences between the orthodontic g roup and malocclusion group in the distribution of anamnestic, clinical dysfunct ion and occlusion indices (P

Anterior disc displacement of temporomandibular joint induced by persistent traction through orbit / 实用口腔医学杂志

Objective:To establishing model of anterior disc displacement(ADD) of temporomandibular joint(TMJ) by persistent inducement of traction through orbit. Methods:The inferior and posterior walls of orbit of right side in 8 rabbits were exposed. The anterior part of disc was vertically passed through using a suture needle with an elastic rubber. The double strands of the elastic rubber was stretched forward from 7 mm to 16 mm and fixed in the hole drilled in the zygomatic arch bellow inferior orbit. The rabbits were killed 1,2,4 and 8 weeks after operation respectively, then both TMJs of each were resected. The paraffin sections were made and stained with hematoxylin & eosin. Results:The mandible of the rabbits deviated to the left side with inclined attribution of incisors. The disc was displaced forward and the degree of ADD in the rabbits was similar. Conclusions:The disc anterior displacement of temporomandibular joint can be induced by persitent anterior traction of the disc.