The Effect of Intraradicular Multiple Fiber and Cast Posts on the Fracture Resistance of Endodontically Treated Teeth with Wide Root Canals

Abstract

Introduction The endodontically treated teeth (ETT) with thin remaining radicular dentin thickness are predisposed to fracture; hence it requires the diligent selection and the execution of endodontic post treatment. The objective of the study was to evaluate the reinforcing effect of both multiple fiber reinforced composite (FRC) and Ni-Cr cast metal posts at anterior and posterior regions. Material and Methods Forty recently extracted root canal treated canine and single rooted premolar teeth were used for the study. They were randomly divided into four groups (n=10) as: Group 1, single FRC post; Group 2, multiple FRC posts; Group 3, single Ni-Cr metal post, Group 4, multiple Ni-Cr posts. The posts were cemented with self-adhesive resin cement and subsequently restored with full veneer metal crown. The compressive static load at 1300 for canine and 450 for premolar was applied with the cross-head speed of 0.5mm/minute until the fracture. The obtained data was analyzed using the Kruskal–Wallis and Pairwise comparison tests with SPSS. Results The results indicate that multiple FRC post restored canine had the maximum fracture load (1843.80±7.13 N), followed by cast multiple posts (1648.99±26.84 N), single fiber post (1623±40.31 N), and cast metal single post (1493±27.33 N). A similar trend was observed in premolar with higher max fracture load with multiple FRC posts at 1920.86±20.61 N and multiple cast metal posts at 1735.43±6.05 N. Conclusion The restoration of ETT with larger canals by multiple FRC and metal posts provides substantially higher fracture resistance in comparison to wider single post.

Assessment of Push Out Bond Strength and Cement Thickness for Oval Root Canals Restored with Different Post Techniques

“…These posts have gained their attractiveness due to many advantages: very good esthetic results, easy procedure, less clinical time, easy retrievability and preservation of the remaining tooth structure (5,6 ,7) . On the top of that is the main advantage of the glass fiber post which is the compatibility of its modulus of elasticity with that of the dentin, giving it a unique property that aids in protection of endodontically treated teeth from root fractures (7,8) . These posts are cemented to dentin with adhesive resin cements, thus allowing this assembly to become biomimicry, therefore more uniform stress distribution is allowed throughout the radicular dentin and less susceptibility to unrestorable fractures is reached (8,9) .…”

“…Previous reports showed that 90% of the mandibular first premolars have oval shaped canals starting at the CEJ and extending up to almost 2mm from the anatomical apex (5,8,13) . To be able to place the circular fiber post in the oval flared canals, additional shaping of the root canal must be done through sound intra-radicular dentin removal to match the shape of a larger circular fiber post to the flared canals, this will compromise the tooth fracture resistance (7) and increase the risk of root perforation or fracture (3,14,15) . Otherwise, cementation of the mismatched circular fiber post within the oval canals associated with an excessive thick layer of resin cements (16,17) leading to the presence of voids or gaps from the luting process.…”

“…Otherwise, cementation of the mismatched circular fiber post within the oval canals associated with an excessive thick layer of resin cements (16,17) leading to the presence of voids or gaps from the luting process. This will generate high stresses at the non-homogenous luting interphase resulting in compromised bond strength of the post (7,9) . Furthermore, the polymerization shrinkage of thick adhesive resin cement will further magnify the stress concentration and failure in adhesive bonding (7) .…”

“…This will generate high stresses at the non-homogenous luting interphase resulting in compromised bond strength of the post (7,9) . Furthermore, the polymerization shrinkage of thick adhesive resin cement will further magnify the stress concentration and failure in adhesive bonding (7) .…”

“…Many attempts have been tried to overcome this shortcoming with oval canals. Among them are the trial of relining the circular post with composite resin to obtain adaptation to the post before cementation (18) , the use of several small posts or the use of accessory post technique in which supplementary posts are added along with the main fiber post in an attempt to improve adaptation and decrease luting cement volume (7,19,20) . Oval glass fiber posts have been introduced to overcome the clinical limitations of circular fiber posts and to extend the indications of the fiber posts to include all types and shapes of root canals.…”