الفهرس 
Introduction .Only 14 pages are availabe for public view
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Abstract
Endodontic treatment offers excellent clinical outcomes for devitalized teeth, increasing tooth survival in both esthetic and structural aspects(2). Post and core materials have been used to reinforce endodontically treated teeth, with ideal restoration involving post placement and core only (39). Fiber post systems, made from carbon or glass fiber, have mechanical properties similar to dentin, resulting in similar stress patterns as intact teeth. Fiber post systems require less post space preparation and are more conservative, but poor adaptation in oval canals can lead to decreased retention and increased cement thickness (4). Polyetheretherketone (PEEK) is a thermoplastic polymer with high mechanical properties, making it an alternative to metal-supported ceramics in dentistry. PEEK is suitable for crowns, implants, temporary abutments, implant-supported hybrid prostheses, and post (7).
Objective: This in vitro study aimed to assess the internal fit and marginal adaptation of two different types of posts: customized fiber post, custom made PEEK post with core with or without ferrule preparation.
Methods: A total of 24 single rooted human extracted mandibular premolar teeth with approximate similarity in shape and size and free of cracks or caries were selected for this study. Samples were divided into two groups with ferrule group and without ferrule group followed by coronal decapitation of all samples. Endodontic treatment was performed for all samples followed by mounting of samples in acrylic blocks and then preparation of post space. Each group of the two groups were subdivided into two subgroups, first subgroup received custom made PEEK post and core and second subgroup received customized fiber post and composite resin core.
Results: According to internal fit:
Customized fiber post (0.23±0.10) had a higher value than custom PEEK post (0.20±0.06) yet the difference was not statistically significant (p=0.324).
Samples without ferrule (0.22±0.08) had a higher value than samples with ferrule (0.21±0.08) yet the difference was not statistically significant (p=0.644).
According to marginal adaptation:
Custom PEEK post (0.42±0.09) had a higher value than customized fiber post (0.40±0.12) yet the difference was not statistically significant (p=0.710).
Samples without ferrule (0.44±0.08) had a higher value than samples with ferrule (0.39±0.12) yet the difference was not statistically significant (p=0.287).
Therefore, both the type of post and ferrule condition had no significant effect on internal fit and marginal adaptation.