【正确答案】What are the five mechanical objectives of root canal shaping? ①Develop a continuously tapering form ②Make the canal narrower apically with the narrowest cross-sectional diameter at its terminus ③Make the preparation in multiple planes ④Never transport the foramen ⑤Keep the apical foramen as small as practical ⑥To clean and seal foramen, MAF should be at least No.20 or 25 in the ISO sizing