{'fraction_non_alphanumeric': 0.02326440177252585, 'fraction_numerical': 0.0011078286558345643, 'mean_word_length': 5.45, '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}}
EVALUATION OF DIFFERENT TYPES OF CROWNS USED FOR RESTORATION OF ENDODONTICALLY TREATED TEETH

Endodontically treated teeth (ETT) have been problematic in most cases as a result of dental caries, fractures, previous restorations and endodontic procedures. Several post system techniques and materials are currently used to build up ETT with moderate or severe loss of coronal tooth structure and to retain final restorations. Following root filling, the custom-made cast metallic post and core with metal-ceramic crowns was the traditional restoration of choice, but this has changed. The patients’ primary motivation for seeking superior dental aesthetics, particularly in the anterior aesthetic zone, has prompted the development of non-metallic restorations. Several new types of polymeric and more aesthetic quartz and glass-fibres posts, combined with direct resin composite cores, provide an aesthetic foundation for an all-ceramic crown and have overcome the aesthetic limitations of metallic posts and cores in the anterior teeth. Until recently, there has been controversy in the dental community regarding which material or technique is the most favourable for the restoration of ETT. It seems that the amount and retentive capacity of the remaining tooth structure, the position of the tooth in the dental arch, the functional or para-functional loading on the tooth, and the treatment plan to restore aesthetics and function all influence the selection of the most appropriate post system for each case.  Hence the present study was planned for Evaluation of Different Types of Crowns Used For Restoration Of Endodontically Treated Teeth. 
The present study was planned in Department of Conservative Dentistry and Endodontics, Buddha Institute of Dental Science and Hospital, Patna, Bihar, India. The 40 cases of maxillary anterior endodontically treated teeth (ETT). The roots were restored with reinforced GFPs (Relaxy Fiber Post, 3M ESPE, Germany), and composite resin cores (Tertic-N-Ceramic, Ivoclar Vivadent, Lichenestine). 
The survival of ETT is contingent on the residual sound tooth structure that remains after the endodontic access and caries removal are performed consequently the most important factors upon restoring ETT become the maximum preservation and conservation of enamel, dentin and the dentinoenamel junction. Hence, bonded partial restorations are always preferred over full coverage cementable crowns. More clinical studies comparing adhesive crowns bonded to postless build-ups or post and -core build-ups are needed for a better understanding of postless approaches in biomimetic restorative dentistry. 
Keywords: Endodontically treated teeth, Crown, cores, post, etc.