Extracellular calcium regulates the adhesion and migration of osteoclasts via integrin αv ß 3 /Rho A/Cytoskeleton signaling.

Integrin αv ß3 is a transmembrane integrin, which can initiate osteoclasts' attachment on bones, leading to downward signaling pathways and subsequent bone resorption. Different calcium concentrations have been reported to have an influence on the activation of integrin αv ß3 . To elucidate the regulatory mechanism of extracellular calcium concentrations on osteoclasts, a controlled micro flow plate (M04S) was utilized in the ONIX flow control system to observe the osteoclasts' adhesion and migration in different calcium concentration media. Fluorescent staining is conducted to show the distribution of integrin αv ß3 and cytoskeleton reorganization. In addition, western blots were performed to detect the expression of integrin αv ß3 and its downstream signaling pathways related to bone resorption. Also, real-time reverse-transcription polymerase chain reaction data of transcription co-activator (YAP/TAZ) and hydrolytic enzymes (the matrix metalloproteinase 9 and cathepsin K) are evaluated. Our findings suggest that osteoclasts' migration and adhesion is better promoted at 0.5 mM than 1.2 mM, which can be partly explained by the induced cytoskeleton organization via integrin αv ß3 /Rho GTPase. But the activation and nuclear localization of YAP/TAZ, and the secretion of hydrolytic enzymes were upregulated when the calcium concentration is at a higher level (1.2 mM). According to our study, there is a high possibility that the migration and attachment of osteoclasts and subsequent osteoclastic bone resorption are regulated over a specific range of extracellular calcium concentration.

Maintenance of the Maxillomandibular Position with Digital Workflow in Oral Rehabilitation: A Technical Note.

Prosthodontic oral rehabilitation procedures are time consuming and require efforts to maintain the confirmed maxillomandibular relationship. Several occlusal registrations and impressions are needed, and cross-mounting is performed to transfer the diagnostic wax-up to master working casts. The introduction of a digital workflow protocol reduces steps in the required process, and occlusal registrations with less deformation are used. The outcome is a maintained maxillomandibular position that is accurately and conveniently transferred.

Worn is born: The role of the maxillo-mandibular relation in management of worn dentition.

Worn dentition, often accompanied by occlusion changes such as reduced vertical dimension, poses a big challenge to both diagnosis and treatment. Current established causes fail to explain the observed tooth wearing patterns, and the treatments based on the documented pathogeneses are often unpredictable and require frequent maintenance. From the perspective of stomatognathic system, we postulate that the role of maxillo-mandibular relation is a crucial part in the tooth wear progression patterns, and should be well addressed in treatment planning. Incompatible occlusion with the inherent tendency of maxillo-mandibular relation has a profound effect on either wearing of natural teeth or failures of restorations. With the aid of cephalometrics and analysis of occlusion it is now possible to reduce this fallacy and achieve a harmony by re-designing the occlusion. According to our treated worn dentition cases, the restoring treatment guided by the tendency of maxillo-mandibular relation showed very promising results.

Suture compression induced midpalatal suture chondrocyte apoptosis with increased caspase-3, caspase-9, Bad, Bak, Bax and Bid expression.

OBJECTIVE: Previous studies found bone resorption and chondrocytes loss in mouse models of mid-palatal suture when given continuous compressive force, although chondrocytes response remained unknown. Herein, we design this study to determine how continuous compression force induces chondrocytes apoptosis. METHODS: Thirty C57BL/6 male mice (aged 6 weeks) were randomly assigned into controls (not ligated to a spring), blank controls (ligated with no compression) and the compression group (ligated with 20-g compression). After 4 d, palatal tissues were sampled and stained by TB and safranin-O. Tunel staining measured the percentage of apoptotic chondrocytes, and immunohistochemistry was performed to label apoptosis-associated proteins (e.g., Bcl-2, Bcl-xl, Bax, Bak, Bid, Bad, caspase-3, caspase-8 and caspase-9). Intergroup comparison was made by the rank sum test, and P < 0.05 was defined as statistical significance. RESULTS: After 7d of induction, TB and safranin-O staining revealed that the cartilage area in the compression group was significantly decreased, while the control group remained largely unaltered. Tunel staining showed that apoptotic cell numbers in the mid-palatal suture were significantly higher than the control group. Immunohistochemistry showed that mice in the compression group had significantly increased expression of caspase-3, caspase-9, Bad, Bak, Bax and Bid; However, caspase-8 remained unaltered. No expression of Bcl-2 and Bcl-xl was detected. CONCLUSIONS: Continuous compression force induces chondrocytes apoptosis in the mid-palatal suture. This process might be associated with the mitochondrial pathway.