For nearly 300 years, clinicians have written about the placement of posts in the roots of teeth to retain restorations. As early as 1728, Pierre Fauchard described the use of “tenons,” or metal posts screwed into the roots of teeth to retain bridges. The 19th century saw wooden posts and post-retained crowns with a porcelain facing, and the 1930s witnessed the birth of the iconic cast post and core system. Finally, in the 1990s tooth-colored fiber posts debuted as an alternative to these conventional metal post systems.
Current concepts supported by evidence-based research indicate that the primary objective of any post and core system is to replace missing coronal tooth structure, to retain the core, and to provide sufficient retention and resistance form to the final restoration to restore original form and function. However, the failure of these post-retained systems has been documented in numerous clinical studies, owing to recurrent caries, endodontic failure, periodontal disease, post dislodgment, cement failure, post-core separation, core fracture, post fracture, tooth fracture, root perforation, and root fracture.
In Douglas Terry’s new book, Restoring the Intraradicular Space: Esthetic Post Systems, he explains that “no single post system meets the demands for favorable biomechanical compatibility or provides the perfect restoration solution for every clinical circumstance, and each situation requires an individual evaluation.” His book explains when, how, and why you should consider post and core systems in restorative dentistry, as well as which type of system to use according to the individual patient’s clinical presentation and esthetic demand. In the case that follows, a gold post and core with metal-ceramic crown was replaced with a custom-made glass fiber post system to optimize esthetics and conserve as much natural tooth structure as possible.
Total-etch technique with Ribbond reinforcement fiber
The patient presented with concern regarding the variation in tooth color and the discoloration of existing large composite restorations on his maxillary anterior teeth (Fig 1). He indicated there was a discrepancy in size, shape, and orientation of both the natural teeth and existing restorations. He also revealed that he had never been happy with the existing metal-ceramic crown on the maxillary left central incisor. The patient was aware of the discoloration of the tissue in the cervical region and reported bleeding on brushing.
Upon clinical and radiographic examination, it was determined that the maxillary left central incisor had previously been endodontically treated, and an ill-fitting custom fabricated gold post was present (Fig 2). Marginal discrepancies at the interface of the metal-ceramic crown can result in bacterial infiltration and inflammation. The discoloration and shadowing of the gingiva at the cervical aspect of the tooth was a result of the incidental light being blocked by the gold post and the metal substructure of the crown (Fig 3). This causes the characteristic bluish shadow at the submarginal zone (Fig 4).
After removal of the metal-ceramic crown, the gold post was easily removed with an ultrasonic Piezo scaler (Figs 5 to 8). The gutta-percha was removed with a series of Gates Glidden drills (#1, #2, #3) to a newly established length; the length of the post channel was established as one-half the length of the root while maintaining an adequate apical seal (Fig 9). A post drill the size of the existing post space was selected to remove debris from the walls of the post channel without enlarging the diameter (Fig 10). The prepared post channel length was accomplished with minimal additional preparation because there is no designated orifice size with the use of bondable polyethylene woven reinforcement fiber (Ribbond-THM, Ribbond). This method can be used for retreatment of an enlarged post channel, and it provides improved internal adaptation to the surface irregularities of the root surface.
Before placing the adhesive or resin cement, a 2-mm-wide reinforcement fiber (Ribbond-THM) was selected, and the fiber was transported to the base of the post space with a Luk’s gutta-percha condenser (Fig 12). It is recommended to rehearse the placement of the fiber into the post channel to ensure proper positioning and complete seating of the material. The appropriate length of the fiber is determined by folding the material once in the canal and folding back on each end, which is approximately six times the height of the anticipated preparation. The plasma-coated ribbon is measured and coated with an unfilled light-cured resin bonding adhesive or a composite sealant.
After an etch-and-rinse protocol and after adhesive was placed and air dried, a dual-cured composite resin cement was injected into the post channel with a needle tube syringe (Centrix). The resin material should flow easily, and the working time should be as long as possible. It is important to place the tip at the base of the post space; the resin material is injected as the syringe tip is slowly removed. This technique reduces the possibility of entrapping air bubbles and ensures optimal adaptation of the resin material to the post hole preparation. The fiber is immediately inserted into the posthole with the modified Luk’s gutta-percha condenser and the fiber is folded over so that the ends are pointing back into the post channel and between the emerging ends of the fiber (Fig 13). The folded ends are arranged into the desired shape of the core and light-cured for 60 seconds.
A dual-cured radiopaque core material was injected over the positioned fibers with a Centrix syringe tip (Accudose Low Viscosity Tube) and adapted with an interproximal instrument (IPC-L, American Eagle) and shaped with a flat sable brush (# 2 sable brush) to an ideal coronal preparation form and dimension (Figs 14 to 16). Finishing resulted in an ideal abutment with a 2-mm circumferential ferrule design to enhance mechanical retention and resistance (Figs 17 and 18).
With this technique, an optimal adhesive integration is achieved between the components of the post-retained system using the direct custom-made glass fiber post system (Fig 19). Figures 20 and 21 show the completed anterior restorative complex immediately after cementation with optimal esthetic results. Figure 22 shows the 3-year postoperative result, demonstrating stability at the interface and an improved gingival color.
Discover more
To see more cases like this and discover why esthetic post systems are a valuable part of any dentist’s armamentarium, check out Douglas Terry’s new book, available now. Hear him explain his philosophy here: http://www.quintpub.com/video_preview/B0561.mp4. And preview the book here: http://www.quintpub.com/PDFs/book_preview/Terry_preview.pdf.
Restoring the Intraradicular Space: Esthetic Post Systems
Douglas A. Terry
Too often patients with fractured teeth are referred for extraction and implant placement with little consideration given to the conservative option of post and core treatment. But it has been demonstrated that endodontic and implant therapies have equivalent results when the treatments are appropriately chosen and performed at a high level of expertise. After all, advancements in endodontic technology and instrumentation have allowed the clinician to visualize, identify, and treat complexities they could not have fathomed a decade ago, and advancements in restorative material formulations have expanded the treatment possibilities for the patient, clinician, and technician. This changing technology has allowed the clinician to treat many clinical challenges through simpler, more conservative, and more economical methods. As such, this text provides a detailed and scientific description of the evolution of the post and core system and the significance of the adhesive design concept when restoring the intraradicular post space. The author presents the various applications and restorative techniques that he uses on a daily basis for restoring the post space, and the esthetics speak for themselves. Every aspect is covered, from general design criteria and the components of the post and core systems to post materials, adhesive bonding and luting agents, material selection, core buildup, and finally, the extracoronal restoration. The clinical protocols are illustrated meticulously and with stunning quality, and additional scientific content can be accessed via QR code. If you want minimally invasive treatment with maximal esthetics, this book is for you.
268 pp; 895 illus; ©2021; ISBN 978-1-64724-056-1 (B0561); US $168