Rheumatoid arthritis (RA), an autoimmune disease characterized by chronic inflammation of synovial tissue, is divided into two subtypes-anti-citrullinated protein antibody (ACPA)-positive and ACPA-negative RA. While the pathogenic mechanisms of ACPA-positive RA are well-understood, the etiology of ACPA-negative RA remains largely unknown. The association between RA and periodontitis (PD) has been observed since the early 1900s, with the two diseases sharing common genetic and environmental risk factors that lead to the progressive destruction of bone and connective tissue. However, the associations between PD and the two subtypes of RA differ. This comprehensive review aims to provide an updated understanding of the epidemiological association between RA and PD, explore potential pathogenic mechanisms linking the two diseases, and highlight the key distinctions between the subtypes of RA and their respective associations with PD. We also discuss the possibility of early intervention or the treatment of the two diseases. Ultimately, this review aims to provide valuable insights for future research in this field.
Humans ; Arthritis, Rheumatoid/complications* ; Periodontitis/complications* ; Anti-Citrullinated Protein Antibodies/immunology* ; Risk Factors

Objective: To observe the effect of compound preparation of milkvetch root and breviscapine (HDs) on the activity of superoxide dismutase (SOD) and lactate dehydrogenase(LDH), the concentration of malondialdehyde (MDA) in blood and brain and memory impairment in Alzheimer's disease rats.Methods: The rats were randomly divided into 5 groups (10 rats /group): the normal control group, Alzheimer's disease (AD) model group induced by AlCl3(5 mg·kg -1·d-1,ig) and D-gal (40 mg·kg-1·d-1,ip), and 3 AD groups respectively treated with different drugs including piracetam (0.15 g·kg-1·d-1,ig), HDs1(1.5 ml·kg-1·d-1,ip) and HDs2 (3 ml·kg-1·d-1,ip).After 90-day treatment, the step-down test was used to detect the learning and memory ability, and SOD and LDH activity and MDA concentration in blood and brain were examined as well.Results: Compared with that in AD model group, the ability of learning and memory was improved, the activity of SOD and LDH increased significantly, the concentration of MDA decreased significantly in blood and brain in HDs treated groups.The differences were statistically significant (P<0.05 or P<0.01), but they were not restored to normal levels.Some indexes of HDs2 group were better than those of piracetam positive control group and HDs1 group (P<0.05 or P<0.01).Conclusion: HDs can effectively reduce MDA concentration, increase SOD and LDH activity in blood and brain, and improve the ability of learning and memory of AD rats.

Objective To design and fabricate the custom-made titanium mandibular condyle by the reverse engineering technology combined with selective laser melting (SLM) technology and to explore the mechanical properties of the SLM-processed samples and the application of the custom-made condyle in the temporomandibular joint(TMJ) reconstruction.Methods The three-dimensional model of the mandibular condyle was obtained from a series of CT databases.The custom-made condyle model was designed by the reverse engineering software.The mandibular condyle was made of titanium powder with a particle size of 20-65 μm as the basic material and the processing was carried out in an argon atmosphere by the SLM machine.The yield strength,ultimate strength,bending strength,hardness,surface morphology and roughness were tested and analyzed.The finite element analysis (FEA) was used to analyze the stress distribution.Results The complex geometry and the surface of the custom-made condyle can be reproduced precisely by the SLM.The mechanical results showed that the yield strength,ultimate strength,bending strength and hardness were (559±14) MPa,(659±32) MPa,(1 067±42) MPa,and(212±4) HV,respectively.The surface roughness was reduced by sandblast treatment.Conclusions The custom-made titanium condyle can be fabricated by SLM technology which is time-saving and highly digitized.The mechanical properties of the SLM sample can meet the requirements of surgical implant material in the clinic.The possibility of fabricating custom-made titanium mandibular condyle combined with the FEA opens new interesting perspectives for TMJ reconstruction.