BACKGROUND:Leukoplakia is a common adverse reaction to traditional orthodontic treatment.There are still some controversies about the difference between light-transmitting clear and fixed aligners in the periodontal health status,incidence of leukoplakia,saliva and related bacteria in patients undergoing orthodontic treatment.OBJECTIVE:To compare the effects of clear and fixed aligners on the smooth surface of orthodontic teeth using Universal Visual Scoring System.METHODS:A total of 80 patients admitted to Department of Orthodontics,Second Hospital of Hebei Medical University from January 2018 to December 2022 were selected and randomly divided into a control group(n=40)and an observation group(n=40)using a random number table method.The control group received orthodontic treatment with fixed aligners,and the observation group received orthodontic treatment with clear aligners.Before treatment and after 6,12,and 24 months of treatment,the labial or buccal sides of teeth 13,33,16,and 36 were selected for each patient as the research subjects,and the visual scoring system was used to evaluate the white spot lesions.RESULTS AND CONCLUSION:(1)Before treatment and after 6,12,and 24 months of treatment,there was no significant difference in the color of tooth white spots and the severity of caries between the two groups of patients(P＞0.05).(2)For tooth 13,after 12 months of treatment,the color grade and caries severity of white spots were both higher than before treatment(P＜0.05).For tooth 33,the color grade and caries severity after 12 months of treatment were both higher than before treatment(P＜0.05).The severity of caries after 12 months of treatment was higher than that after 6 months of treatment(P＜0.05).For tooth 16,the color grade of white spots and the severity of caries after 12 months of treatment were both higher than those after 6 months of treatment(P＜0.05).(3)Multi-level ordered multi-classification Logistic regression model analysis showed that the color and severity of white spots on different teeth had little correlation with the type of appliance and were greatly affected by the correction time factor.Among them,the color change and severity of the initial white spots on teeth 33 and 13 were statistically significant at 12 and 24 months of treatment.(4)It is not possible to conclude that there is a difference in the effect of fixed and clear aligners on the white spot lesions of smooth surfaces of the teeth,but an increase in the risk of dental caries with the increase in the duration of treatment can be detected.

BACKGROUND:Leukoplakia is a common adverse reaction to traditional orthodontic treatment.There are still some controversies about the difference between light-transmitting clear and fixed aligners in the periodontal health status,incidence of leukoplakia,saliva and related bacteria in patients undergoing orthodontic treatment.OBJECTIVE:To compare the effects of clear and fixed aligners on the smooth surface of orthodontic teeth using Universal Visual Scoring System.METHODS:A total of 80 patients admitted to Department of Orthodontics,Second Hospital of Hebei Medical University from January 2018 to December 2022 were selected and randomly divided into a control group(n=40)and an observation group(n=40)using a random number table method.The control group received orthodontic treatment with fixed aligners,and the observation group received orthodontic treatment with clear aligners.Before treatment and after 6,12,and 24 months of treatment,the labial or buccal sides of teeth 13,33,16,and 36 were selected for each patient as the research subjects,and the visual scoring system was used to evaluate the white spot lesions.RESULTS AND CONCLUSION:(1)Before treatment and after 6,12,and 24 months of treatment,there was no significant difference in the color of tooth white spots and the severity of caries between the two groups of patients(P＞0.05).(2)For tooth 13,after 12 months of treatment,the color grade and caries severity of white spots were both higher than before treatment(P＜0.05).For tooth 33,the color grade and caries severity after 12 months of treatment were both higher than before treatment(P＜0.05).The severity of caries after 12 months of treatment was higher than that after 6 months of treatment(P＜0.05).For tooth 16,the color grade of white spots and the severity of caries after 12 months of treatment were both higher than those after 6 months of treatment(P＜0.05).(3)Multi-level ordered multi-classification Logistic regression model analysis showed that the color and severity of white spots on different teeth had little correlation with the type of appliance and were greatly affected by the correction time factor.Among them,the color change and severity of the initial white spots on teeth 33 and 13 were statistically significant at 12 and 24 months of treatment.(4)It is not possible to conclude that there is a difference in the effect of fixed and clear aligners on the white spot lesions of smooth surfaces of the teeth,but an increase in the risk of dental caries with the increase in the duration of treatment can be detected.

Levonorgestrel releasing intrauterine system (LNG-IUS), an intrauterine device (IUD) containing slowly released progestogen, is the common IUD in China. LNG-IUS is not only a long-term, reversible and safe contraceptive method, but also used in the adjuvant treatment of some gynecological diseases. Nowadays, women are more concerned about the quality of sex life and reproductive health when choosing their contraceptive methods. This review will focus on the present researches and summarize the effects of LNG-IUS on users' sexual life quality, to provide references for the choice of contraceptive methods.

Levonorgestrel releasing intrauterine system (LNG-IUS), an intrauterine device (IUD) containing slowly released progestogen, is the common IUD in China. LNG-IUS is not only a long-term, reversible and safe contraceptive method, but also used in the adjuvant treatment of some gynecological diseases. Nowadays, women are more concerned about the quality of sex life and reproductive health when choosing their contraceptive methods. This review will focus on the present researches and summarize the effects of LNG-IUS on users' sexual life quality, to provide references for the choice of contraceptive methods.

Objective: To explore the correlation between menopausal hormone therapy（MHT）and breast lesions in perimenopausal women,and to provide evidence for safe use of MHT. Methods: The 40-60 year-old women who visited Hangzhou Women's Hospital and met the diagnostic criteria for perimenopausal syndrome were recruited. The intervention group received MHT and was divided into three subgroups according to the MHT regimen：estrogen-progesterone cycle therapy（A）,estrogen-progesterone continuous therapy（B）,estrogen therapy（C）. The control group did not receive MHT. All the patients received regular mammography to quantify and evaluate breast lesions. The generalized estimating equation was used to analyze the changes of breast lesions between different groups. Results: There were 80 cases in the intervention group,with 49 in group A,26 in group B,5 in group C,and 80 cases in the control group. After two years of follow-up,there was no statistically significant differences of time,group and interaction in breast density,volume of breast fibrous tissue and the volume of breast between three intervention groups and the control group（P>0.05）; there was no statistically significant differences of group and interaction in positive rate of calcification and breast mass between the intervention group and the control group（P>0.05）. Conclusion Receiving MHT intervention for two years did not increase the risk of breast lesions.

Nitrogen source is one of the important factors that affect the microalgae growth and lipid accumulation. We studied the effects of various nitrogen sources (i.e. NaNO3, CO(NH2)2, NH4Cl and CH3COONH4) and amount on the growth density, lipid yield, and eicosapentaenoic acid (EPA) content of Nannochloropsis oculata by single factor experimental method. The results show that N. oculata preferred NH4+ as nitrogen source rather than NO3- and CO(NH2)2. NH4+ could promote the growth and lipid accumulation of N. oculata. With the increase of nitrogen concentration, the biomass and the content of polyunsaturated fatty acid (PUFA) increased, but the content of lipid decreased. CH3COONH4 was the most suitable for growth, accumulation of lipid and EPA of N. oculata among the four investigated nitrogen sources. The optimal concentration was 5.29 mmol/L.
Eicosapentaenoic Acid ; metabolism ; Lipids ; biosynthesis ; isolation & purification ; Microalgae ; growth & development ; metabolism ; Nitrogen ; analysis ; metabolism ; Stramenopiles ; growth & development ; metabolism