OBJECTIVE: To investigate the effect of orthodontic traction on the microstructure of dental enamel. METHODS: Forty-eight isolated premolars were randomly divided into 6 groups (=8), including Group A (blank control group), in which the teeth were bonded with the orthodontic brackets without any loading force; Groups B1, B2, and B3 where the teeth were bonded with the orthodontic brackets using clinical adhesives and loaded with 50 g force for 6 months, 200 g force for 6 months, and 200 g force for 1 month, respectively; and Groups C1 and C2, where the teeth were bonded with straight wire brackets using light curing bonding and chemical curing bonding techniques, respectively. All the teeth were embedded with non-decalcified epoxy resin. Scanning electron microscope (SEM), atomic force microscope (AFM), and energy spectrometer (EDS) were used to analyze interface morphology and elemental composition of the teeth sliced with a hard tissue microtome. RESULTS: Compared with those in Group A, the teeth in the other 5 groups showed increased adhesive residue index with microcracks and void structures on the enamel surface under SEM; AFM revealed microcracks on the enamel surface with angles to the grinding direction. A larger loading force on the bracket resulted in more microcracks on the enamel interface. The interface roughness differed significantly between Groups A and C2, and the peak-to-valley distance differed significantly between Groups A, C, and C2. CONCLUSIONS Orthodontic traction can cause changes in the microstructure of normal dental enamel.
Dental Enamel ; Materials Testing ; Orthodontic Brackets ; Resin Cements ; Surface Properties ; Traction

ObjectiveTo investigate the efficacy and safety of Shengxiantang in the treatment of early Parkinson's disease with autonomic dysfunction of Qi deficiency pattern. MethodA total of 82 eligible patients were randomized into control group （41 cases） and traditional Chinese medicine （TCM） group （41 cases）. On the basis of standardized treatment of western medicine， TCM group was prescribed Shengxiantang while control group were treated with placebo for 12 consecutive weeks additionally. Scale for Outcomes in Parkinson's Disease-Autonomic （SCOPA-AUT） questionnaire， Unified Parkinson's Disease Rating Scale （UPDRS）， Traditional Chinese Medicine Qi Deficiency Symptom Score of Parkinson's Disease （TCMQDSSPD）， serum levels of glutathione peroxidase （GPx） and superoxide dismutase （SOD）， daily dosage of pramipexole and levodopa and benserazide hydrochloride， and safety index were evaluated both before and after treatment. ResultAfter treatment， the total score of SCOPA-AUT， gastrointestinal score， urinary score， and thermoregulatory score in the control group were higher than those before treatment （P<0.01）， while the above sores in the TCM group were lower than those before treatment （P<0.05， P<0.01）. In addition， the cardiovascular score， pupillomotor score， and sexual score in two groups showed no significant difference from those before treatment. After treatment， the total score of SCOPA-AUT， gastrointestinal score， urinary score， and thermoregulatory score in the TCM group were lower than those in the control group （P<0.05， P<0.01）， and cardiovascular score， pupillomotor score， and sexual score showed no significant difference between two groups. After treatment， the total score of TCMQDSSPD， main symptom scores， and minor symptom scores in the control group had no significant difference from those before treatment. The total score of TCMQDSSPD and minor symptom scores of TCM group were lower than those before treatment （P<0.01）， while the main symptom scores of the TCM group showed no significant difference from those before treatment. After treatment， the UPDRS score， serum GPx and SOD levels， and daily dosage of pramipexole and levodopa and benserazide hydrochloride demonstrated no significant difference from those before treatment in the two groups and between the two groups. No abnormality was found in the safety indexes. ConclusionBased on the standardized treatment of western medicine， Shengxiantang can effectively and safely improve the autonomic symptoms of gastrointestinal system， urinary system， and thermoregulation， as well as the symptoms of Qi deficiency syndrome in early Parkinson's disease with autonomic dysfunction.