{'fraction_non_alphanumeric': 0.018950437317784258, 'fraction_numerical': 0.0014577259475218659, 'mean_word_length': 5.605769230769231, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[A biomechanical study of the human periodontal ligament]

The structures and mechanical properties of the normal human periodontal ligament(PDL) were investigated by VDA measuring system through the microscope.It was found that the mechanical properties of PDL is not linear.Its mechanical properties are depending on its fibrous properties,directions and components.The linear and index relationships of the tensile and compression stress-strain curve of PDL can be divided into 6 segments.The strain changes and moduli of every segment were calculated.The relationship between periodontal function and the variation law of stress-strain is investigated and its clinic value is shown.