https://www.selleckchem.com/products/nec-1s-7-cl-o-nec1.html BACKGROUND Dental fluorosis is caused by excessive fluoride ingestion during tooth formation. As a consequence, there is a higher porosity on the enamel surface, which causes an opaque look. AIM The aim of this study was to identify a dental intervention to improve the smile in patients with tooth fluorosis. Additional aims were to relate the stain size on fluorotic teeth with the effectiveness of stain removal, enamel loss and procedure time using a manual microabrasion technique with 16% hydrochloric acid (HCL). METHODS An experimental study was carried out on 84 fluorotic teeth in 57 adolescent patients, 33 females and 24 males, with moderate to severe fluorosis. The means, standard deviations and percentages were analyzed using nonparametric statistics and ArchiCAD 15 software was used for the variables including stain size and effectiveness of stain removal. RESULTS The average enamel loss was 234 µm and was significantly related to the procedure time categorized as 1-4 min and 4.01-6 min, resulting in a P > 0.000. The microabrasion technique using 16% HCL was effective in 90.6% of patients and was applied manually on superficial stains in moderate and severe fluorosis. Procedure time was less than 6 min and enamel loss was within the acceptable range. CONCLUSION Microabrasion is a first-line treatment; however, the clinician should measure the average enamel loss to ensure that it is within the approximate range of 250 µm in order to avoid restorative treatment. ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.BACKGROUND Surgical resection is the preferred method for patients with complex liver cancer. But the tumor is in a special position, the surgery is highly risky, postoperative complications can easily occur, and the prognosis is not ideal. AIM To investigate the effectiveness of surgical resection for complex liver cancer and its influencing factors. METHO