Cyclic tensile stress promotes osteogenic differentiation via upregulation of Piezo1 in human dental follicle stem cells.

As periodontal progenitor cells, human dental follicle stem cells (hDFCs) play an important role in regenerative medicine research. Mechanical stimuli exert different regulatory effects on various functions of stem cells. Mechanosensitive ion channels can perceive and transmit mechanical signals. Piezo1 is a novel mechanosensitive cation channel dominated by Ca2+ permeation. The yes-associated protein 1 (YAP1) and mitogen-activated protein kinase (MAPK) pathways can respond to mechanical stimuli and play important roles in cell growth, differentiation, apoptosis, and cell cycle regulation. In this study, we demonstrated that Piezo1 was able to transduce cyclic tension stress (CTS) and promote the osteogenic differentiation of hDFCs by applying CTS of 2000 µstrain to hDFCs. Further investigation of this mechanism revealed that CTS activated Piezo1 in hDFCs and resulted in increased levels of intracellular Ca2+, YAP1 nuclear translocation, and phosphorylated protein expression levels of extracellular signalling-associated kinase 1/2 (ERK 1/2) and Jun amino-terminal kinase 1/2/3 (JNK 1/3) of the MAPK pathway family. However, when Piezo1 was knocked down in the hDFCs, all these increases disappeared. We conclude that CTS activates Piezo1 expression and promotes its osteogenesis via Ca2+/YAP1/MAPK in hDFCs. Appropriate mechanical stimulation promotes the osteogenic differentiation of hDFCs via Piezo1. Targeting Piezo1 may be an effective strategy to regulate the osteogenic differentiation of hDFCs, contributing to MSC-based therapies in the field of bone tissue engineering.

Three-dimensional finite element analysis of the biomechanical properties of different material implants for replacing missing teeth.

The purpose of this study was to analyze the biomechanical properties of implants made of different materials to replace missing teeth by using three-dimensional finite element analysis and provide a theoretic basis for clinical application. CBCT data was imported into the Mimics and 3-Matic to construct the three-dimensional finite element model of a missing tooth restored by an implant. Then, the model was imported into the Marc Mentat. Based on the variations of the implant materials (titanium, titanium-zirconia, zirconia and poly (ether-ether-ketone) (PEEK)) and bone densities (high and low), a total of eight models were created. An axial load of 150 N was applied to the crown of the implant to simulate the actual occlusal situation. Both the maximum values of stresses in the cortical bone and implant were observed in the Zr-low model. The maximum displacements of the implants were also within the normal range except for the PEEK models. The cancellous bone strains were mainly distributed in the apical area of the implant, and the maximum value (3225 µstrain) was found in PEEK-low model. Under the premise of the same implant material, the relevant data from various indices in low-density bone models were larger than that in high-density bone models. From the biomechanical point of view, zirconia, titanium and titanium-zirconia were all acceptable implant materials for replacing missing teeth and possessed excellent mechanical properties, while the application of PEEK material needs to be further optimized and modified.

Removal of Horizontally Impacted Mandibular Third Molars Using the Three-Piece or T-Shaped Tooth Sectioning Method.

BACKGROUND: The extraction of horizontally impacted mandibular third molars (HM3) can be a complicated surgery. Appropriate tooth sectioning methods can reduce the operation time and postoperative complications. PURPOSE: The current study compares operative time and postoperative pain between HM3 removed using the three-piece or T-shaped tooth sectioning techniques. STUDY DESIGN, SETTING, SAMPLE: A randomized single-blind prospective clinical trial on HM3 extraction was carried out between June and December 2022 in the Department of Oral and Maxillofacial Surgery, the Affiliated Stomatological Hospital, Southwest Medical University. Patients with local or systemic infection, poor oral hygiene, and systemic disease were excluded. PREDICTOR VARIABLE: The predictor variable was the tooth sectioning method. The subjects were randomized to a three-piece or T-shaped group. MAIN OUTCOME VARIABLE(S): The primary outcome variables were the operative time and postoperative pain measured using a visual analog scale (VAS). The secondary outcome variables were the rates of primary bleeding, mouth opening reduction, swelling, patient satisfaction measured using a VAS, and quality of life measured using a postoperative symptom severity scale. COVARIATES: The covariates included age, sex, side and classification of HM3, and the relationship of HM3 to the inferior alveolar nerve canal. ANALYSES: The data were analyzed using the independent samples t-test, paired t-test, χ2, and rank sum test. A significance level set at P < .05. RESULTS: The sample included 60 patients in the three-piece group and 66 patients in the T-shaped group. The operative time of the three-piece group (14.73 ± 3.21 minutes) was shorter than that of the T-shaped group (19.25 ± 4.29 minutes) (P < .05). On days 3 and 7, VAS of pain were 2.24 ± 1.89 and 0.15 ± 0.40 in the three-piece group and 3.95 ± 2.44 and 0.48 ± 0.68 in the T-shaped group (P < .05). The VAS of patient satisfaction in the three-piece group (6.05 ± 1.29) was better than the T-shaped group (4.90 ± 1.05) on day 7 (P < .05). CONCLUSION AND RELEVANCE: The three-piece tooth sectioning for HM3 removal was associated with shorter duration, slighter postoperative symptoms, and higher patient satisfaction and may be considered as a recommended practice for dentists.

Unveiling the links between physical activity, self-identity, social anxiety, and emotional eating among overweight and obese young adults.

Introduction: Emotional eating not only contributes to physical obesity but also leads to the experience of guilt and shame, exacerbating emotional problems. Increasing physical activity, adopting a balanced diet, and seeking psychological support help improve emotional eating issues in overweight or obese young adults, enhancing overall mental and physical well-being. Methods: This study investigates the correlation between physical activity, self-identity, social anxiety, and emotional eating among 373 overweight and obese college students aged 18-26 in central China. By utilizing AMOS v.26, a structural equation model was constructed to examine the hypotheses. Results: The findings reveal that physical activity significantly influences self-identity and social anxiety, which, in turn, significantly impact emotional eating. Moreover, self-identity and social anxiety serve as mediators in the relationship between physical activity and emotional eating. These results emphasize the role of physical activity in mitigating emotional eating among young individuals struggling with overweight and obesity. Discussion: Consequently, the government and relevant agencies are urged to address the issue of obesity among young adults and provide support for their engagement in physical activity.