Study on the correlation between the mandibular masticatory muscle movement and sleep tooth wear / 华西口腔医学杂志

OBJECTIVE@#To investigate the correlation between the clinical diagnostic criteria of sleep bruxism and the frequency of mandibular movements during sleep.@*METHODS@#Video polysomnography was used to record 20 healthy adults with at least one of the following clinical symptoms and signs: 1) report of frequent tooth grinding; 2) tooth wear and dentin exposure with at least three occlusal surfaces; 3) masticatory muscle symptoms in the morning; 4) masseter muscle hypertrophy. The rhythmic masticatory muscle activity (RMMA) and isolated tonic activity were scored to compare the correlations with clinical symptoms and signs. Finally, the incidence of temporomandibular disorders (TMD) was investigated in patients with isolated tonic and RMMA subjects.@*RESULTS@#Among the 20 subjects, RMMA events were observed (5.8±3.1) times·h⁻¹ and isolated tonic episodes were observed (2.1±0.9) times·h⁻¹. The frequency of RMMA events was significantly greater in the patients with acoustic molars than in those without (P<0.05). Similarly, the frequency of RMMA events was significantly greater in the patients with tooth attrition than in those without (P<0.05). However, no difference was observed between the occurrence of RMMA and the symptoms of masticatory muscles or masseter hypertrophy in the morning. The incidence of TMD was significantly higher in the patients with RMMA than in the isolated tonic patients.@*CONCLUSIONS@#The clinical symptoms and signs often used to diagnose sleep bruxism are different clinical and physiological mandibular movements during sleep. RMMA during sleep can reflect the occurrence of tooth attrition and the high risk of TMD.

Preparation of a poIy(3-hydroxybutyrate-4-hydroxybutyrate)/poIyvinyI aIcohoI composite scaffoId by coaxiaI eIectrospinning and its biocompatibiIity / 中国组织工程研究

BACKGROUND: Poly(3-hydroxybutyrate-4-hydroxybutyrate) (P3HB4HB) is a kind of polymer material that can be completely degraded, has good film-forming property and physical properties, but has poor hydrophilicity. OBJECTIVE: To prepare P3HB4HB/polyvinyl alcohol (PVA) coaxial electrospun scaffolds, and to investigate the physical properties and biocompatibility of scaffolds in vitro. METHODS: We prepared P3HB4HB electrospun scaffold, PVA electrospun scaffold and P3HB4HB/PVA coaxial electrospun composite scaffold, and then detected the morphology and characterization, contact angle, and tensile mechanical properties of the scaffolds. Passage 4 bone marrow mesenchymal stem cells (BMSCs) from Sprague-Dawley rats were seeded on the three kinds of scaffolds. Cell adhesion rate was detected at 1, 3, 6 hours after seeding; cell proliferation was detect at 1, 3, 5, 7 days after seeding; and cell viability was observed fluorescence staining at 7 days after seeding. Passage 4 BMSCs were seeded onto the three kinds of scaffolds followed by 14 days of osteogenic and chondrogenic induction. Then, alizarin red staining and toluidine blue staining were used to verify BMSCs differentiation potentials. RESULTS AND CONCLUSION: (1) Scaffold morphology: Under the scanning electron microscope, the structure of the scaffold in each group was a three-dimensional interconnected network. The fiber diameters of P3HB4HB electrospun scaffold and P3HB4HB/PVA electrospun scaffold were homogeneous and ordered. The P3HB4HB/PVA scaffold showed an obvious core-shell structure under the transmission electron microscope. (2) Scaffold characterization: The tensile strength, tensile modulus and maximum stress of the P3HB4HB and P3HB4HB/PVA scaffolds were significantly higher than those of the PVA electrospun scaffold (P < 0.05). The contact angle of the P3HB4HB/PVA composite scaffold was less than 90°. (3) Cell adhesion rate was ranked as follows: PVA electrospun scaffold group >P3HB4HB/PVA composite scaffold group > P3HB4HB electrospun scaffold group (P < 0.05). (4) Proliferation and activity of cells: The cell proliferation of the P3HB4HB/PVA composite scaffold group was faster than that of the other two groups at 5 and 7 days (P < 0.05). There were more viable cells on the PVA electrospun scaffold and composite scaffold than on the P3HB4HB electrospun scaffold. (5) Cell differentiation: Osteogenesis and cartilage specific staining of the composite scaffold were stronger than those in the other two groups. Overall, the P3HB4HB/PVA coaxial electrospun scaffold has good biocompatibility and a certain mechanical strength.