Influencing Factors of Healthy Aging Risk Assessed Using Biomarkers: A Life Course Perspective.

Assessing individual risks of healthy aging using biomarkers and identifying associated factors have become important areas of research. In this study, we conducted a literature review of relevant publications between 2018 and 2023 in both Chinese and English databases. Previous studies have predominantly used single biomarkers, such as C-reactive protein, or focused on specific life course stages and factors such as socioeconomic status, mental health, educational levels, and unhealthy lifestyles. By summarizing the progress in this field, our study provides valuable insights and future directions for promoting healthy aging from a life course perspective.

Accumulated biomechanical effects of mandibular molar mesialization using clear aligners with auxiliary devices: an iterative finite element analysis.

BACKGROUND: The biomechanics generated by the clear aligner (CA) material changes continuously during orthodontic tooth movement, but this factor remains unknown during the computer-aid design process and the predictability of molars movement is not as expected. Therefore, the purpose of this study was to propose an iterative finite element method to simulate the long-term biomechanical effects of mandibular molar mesialization (MM) in CA therapy under dual-mechanical systems. METHODS: Three groups including CA alone, CA with a button, and CA with a modified lever arm (MLA) were created. Material properties of CA were obtained by in vitro mechanical experiments. MM was conducted by the rebound force exerted by CA material and the mesial elastic force (2N, 30° to the occlusal plane) applied to the auxiliary devices. Stress intensity and distribution on periodontal ligament (PDL), attachment, button and MLA, and displacement of the second molar (M2) during the iterations were recorded. RESULTS: There was a significant difference between the initial and cumulative long-term displacement. Specifically, compared to the beginning, the maximum stress of PDL decreased by 90% on average in the intermediate and final steps. The aligner was the main mechanical system at first, and then, the additional system exerted by the button and MLA dominated gradually. The stress of attachments and auxiliary devices is mainly concentrated on their interfaces with the tooth. Additionally, MLA provided a distal tipping and extrusive moment, which was the only group that manifested a total mesial displacement of the root. CONCLUSIONS: The innovatively designed MLA was more effective in reducing undesigned mesial tipping and rotation of M2 than the traditional button and CA alone, which provided a therapeutic method for MM. The proposed iterative method simulated tooth movement by considering the mechanical characteristic of CA and its long-term mechanical force changes, which will facilitate better movement prediction and minimize the failure rate.

Biomechanical effects of clear aligners with different thicknesses and gingival-margin morphology for appliance design optimization.

INTRODUCTION: The objectives of this study were to investigate the biomechanical effects of clear aligners (CAs) with various thermoplastic material thicknesses and gingival-margin designs for space closure in extraction treatment and to propose a computer-aided procedure to optimize CA design. METHODS: The radiologic and intraoral scanning technology, in vitro mechanical experiment, viscoelastic modeling, and finite element analysis (FEA) were integrated to establish an orthodontic simulation model. Twelve FEA models of CA were created, comprising combinations of 2 kinds of thicknesses (0.75 and 0.50 mm), 2 forms of gingival-margin shape (scalloped and straight), and 3 types of margin height (-2, 0, and 2 mm). In vitro testing was carried out to determine the actual properties of material thickness. RESULTS: A 0.75-mm-thick aligner resulted in greater periodontal ligament (PDL) stress than 0.50 mm, and there was no clear correlation between the control ability of tooth movement and the thickness. For different margin designs, PDL stress at -2 mm height was significantly lower than those with a higher border. Aligners with straight margins had higher stress than the scalloped aligners, whereas the differences were unnoticeable at 2 mm height. The optimized aligner with differential margin designs was recommended on the basis of biomechanical calculations, which facilitated the efficiency and control of tooth movement for multiple teeth. CONCLUSIONS: The effect of material thickness and margin design of CA on the force and movement differed in different teeth. Preferable CA designs of each tooth during different movement stages should be presented personalized under the guidance of precise biomechanics instead of pure morphologic analysis.

Natural Killer-Like B Cells Secreting Interleukin-18 Induces a Proinflammatory Response in Periodontitis.

Natural killer-like B (NKB) cells, which are newly identified immune subsets, reveal a critical immunoregulatory property in the eradication of microbial infection via the secretion of interleukin (IL)-18. For the first time, this study investigated the role of NKB cells in secreting IL-18 in the pathogenesis of periodontitis. In this study, NKB cells' percentage and IL-18 concentration in peripheral blood and periodontium in periodontitis patients was measured using flow cytometry and ELISA. The role of IL-18 in regulating periodontal inflammation was examined in a Porphyromonas gingivalis (P. gingivalis)-induced periodontitis murine model. Peripheral and periodontal-infiltrating CD3-CD19+NKp46+ NKB cells, which were the main source of IL-18, were elevated and correlated with attachment loss in periodontitis patients. In vitro IL-18 stimulation promoted proinflammatory cytokine production in periodontal ligament cells. P. gingivalis infection induced elevation of IL-18 receptor in periodontium in a periodontitis murine model. IL-18 neutralization not only suppressed P. gingivalis-induced alveolar bone resorption, but also inhibited recruitment of antigen-non-specific inflammatory cells into the periodontium, probably via dampening expressions of cytokines, chemokines, and matrix metalloproteinases. NKB cells secreting IL-18 appeared to be an important mediator in the inflammatory response following intraoral P. gingivalis infection. These findings might be relevant to the development of immunotherapies for periodontitis.

Assessment of available sites for palatal orthodontic mini-implants through cone-beam computed tomography.

OBJECTIVE: To measure the palatal thickness of both hard and soft tissues and to determine safe regions for the placement of mini-implants. The influences of sex and age on palatal thickness were also examined. MATERIALS AND METHODS: Cone-beam computed tomography images of 30 patients (12 males, 18 females), including 15 adults and 15 adolescents, were used in this study. The thicknesses of palatal hard tissue, soft tissue, and hard+soft tissues were measured at the coronal planes of first premolars, second premolars, first molars, and second molars (P1, P2, M1, and M2 planes, respectively). RESULTS: The hard tissue was thickest at the P1 plane, followed by at the P2, M1, and M2 planes, while the thickness of soft tissue was similar among the four planes. The trends in the changes of palatal thickness from midline to the lateral sides (V-pattern) were similar for the four planes. Palatal thickness was influenced by sex, age, and their interaction. Mapping of recommended and optimal sites for palatal mini-implants was accomplished. CONCLUSIONS: Sex and age factors could influence palatal thickness. Therefore, the findings might be helpful for clinicians in guiding them to choose the optimal sites for palatal mini-implants.