{'fraction_non_alphanumeric': 0.01228878648233487, 'fraction_numerical': 0.0030721966205837174, 'mean_word_length': 5.387254901960785, '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}}
Critical discussion of previous experience and new approaches in the development of composite filling materials.

Following the 1975 report in Chicago, an attempt is made to discover the present position with regard to the development of composite filling materials, and to determine whether further development is necessary or even possible. The reasons for considering clinical trials important are given, and the problem of the chemical bond to hard dental tissues is discussed. The influence of the thermal coefficient of expansion on the marginal seal is discussed in relation to border discolouration, and a critical assessment given of acid etching and remineralization. The significance of wear for the maintenance of contours is pointed out, in particular in connection with occlusal surface fillings in the cheek teeth, as well as the problem of contact-point characterization and fracture strength after repair of an old filling. Improvements in UV light polymerization are described. A critical discussion of the different opinions on the significance of histological findings in relation to pulp tolerance is presented, and finally the significance of water uptake and radiological opacity is discussed. In conclusion indications in relation to the present state of development are listed.