ABSTRACT
BACKGROUND:There is an increasing demand for orthodontic treatment,and periodontally accelerated osteogenic orthodontics(PAOO)technique can make it possible to move orthodontic teeth that are limited by thin alveolar bone. OBJECTIVE:To investigate the biomechanics of orthodontic tooth movement before and after periodontally accelerated osteogenic orthodontics(PAOO)surgery to increase alveolar bone volume using the three-dimensional finite element method. METHODS:A patient undergoing PAOO surgery before orthodontic treatment to increase bone volume on the labial side of the mandibular anterior region was selected.The patient was under invisible orthodontics.Two three-dimensional finite element models were constructed based on the patient's preoperative and 6-month postoperative cone beam CT data.Both models simulated the movement of tooth 33:experiment Ⅰ:distal-central movement of 0.25 mm;experiment Ⅱ:lingual movement of 0.25 mm;and experiment Ⅲ:intrusion movement of 0.10 mm.The stress distribution and initial displacement trend of tooth 33,periodontal ligament and surrounding alveolar bone under the action of the invisible aligner were analyzed before and after the PAOO procedure. RESULTS AND CONCLUSION:Dental stress analysis:In the same orthodontic tooth movement,the maximum Von-Mises stress and overall stress values of tooth 33 were all higher before surgery than after surgery;there were similar distribution areas of maximum equivalent stress and overall distribution trends of Von-Mises stress before and after surgery.Periodontal ligament stress analysis:In the same orthodontic tooth movement,the maximum Von-Mises stress and overall stress values of the periodontal ligament were higher before surgery than after surgery,and there were similar distribution areas of the maximum equivalent stress and overall distribution trends of Von-Mises stress before and after surgery.Alveolar bone stress analysis:In the same orthodontic tooth movement,the maximum Von-Mises stress values of the alveolar bone around tooth 33 were higher before surgery than after surgery,while the equivalent stress distribution showed a gradual decrease from the top of the alveolar ridge to the root.Initial displacement analysis:In the same orthodontic tooth movement,the initial displacements in the main displacement direction for all six observation points of tooth 33 were smaller before surgery than after surgery,and showed a tendency to gradually decrease from the tooth tip to the apex.Therefore,there were differences in the biomechanical characteristics of orthodontic tooth movement before and after the PAOO surgery.With the clear aligner,the postoperative equivalent stress values on the dentition,periodontal ligament,and surrounding alveolar bone were lower than before the surgery,and the initial displacements of the orthodontic teeth after the surgery are larger than before.These findings suggest that PAOO can release the restriction of thin alveolar bone on the movement of orthodontic tooth by increasing alveolar bone thickness,effectively improving the force on the roots,periodontal ligament,and alveolar bone,avoiding the stress concentration on orthodontic tooth in the thin alveolar bone area that can cause complications when moving,and improving the efficiency of tooth movement.
ABSTRACT
Hepatocellular carcinoma （HCC） has emerged as a significant public health concern， posing a serious threat to the lives and health of residents in China. Furthermore， the incidence and mortality rates of HCC are notably higher in males than in females. Androgen receptors （AR） can contribute to the occurrence of male-specific cancers such as prostate cancer， suggesting a potential link to the increased susceptibility of males to HCC. Elucidating the cancer-promoting mechanism of AR and developing specific targeted interventions are effective ways to advance tertiary prevention of HCC and improve patient prognosis. This paper reviews the relevant evidence of AR’s role in promoting the occurrence and development of HCC， summarizes relevant mechanisms discovered to date， including promoting the stemness of HCC cells， altering the immune microenvironment， regulating key signaling pathways， inducing glycolysis in hepatocellular carcinoma， and synergizing with hepatitis B virus to promote HCC. Additionally， research directions for targeted interventions in HCC through AR-related signaling pathways are discussed.
ABSTRACT
Objective To explore the effect of intensive hip adductor isometric strength training on the balance ability of functional ankle joint instability. Methods From November, 2019 to January, 2020, 18 college students with functional ankle instability were recruited from a university in Shenzhen and randomly divided into control group (n = 9) and experimental group (n = 9). Both groups received ankle stability training, and the experimental group received isometric muscle strength training of hip adductor in addition, one hour a time, three times a week, for four weeks. The Cumberland Ankle Instability Assessment Questionnaire (CAIT), Y Balance Test (YBT), Balance-check balance equipment and Back-check hip adductor maximum isometric strength test were performed before and after training. Results After training, the scores of CAIT, YBT and balance-check increased in both groups (t > 2.540, P < 0.05); the strength of adductor hip muscle significantly increased in the experimental group (t = 8.485, P < 0.001). The d-value of CAIT score, YBT distance, the score of Balance-check, and the strength of adductor hip muscle were more in the experimental group than in the control group (t > 2.168, P < 0.05); the d-value of the average rotation speed, the maximum rotation speed and the balance level were less in the experimental group than in the control group (t > 2.804, P < 0.05). Conclusion Hip adductor isometric muscle strength training may promote the recovery of the balance after functional ankle instability.