Dental treatment after endodontic therapy can be a challenging clinical situation, particularly where there is significant loss of dental tissue. The main purpose of an intra-radicular post is to retain the core build up in a tooth when coronal tooth structure is lacking.[i] While there is some debate about optimal post material and shape,[ii] overall evidence[iii] shows that, with the right approach, post placement can improve clinical performance and survivability of endodontically treated teeth (ETT).
ETT often require significant restoration due to major tissue loss from caries, fractures, pre-existing restorations or endodontic access. As a result, there can sometimes be little structure remaining to support a restoration. By retaining the core of an ETT, a correctly selected and placed post can enable a severely damaged tooth to be restored.
To fulfil its purpose, a post must fit well and be bonded appropriately. It should be fracture-resistant, and should be able to provide the core with enough strength to retain whichever restoration provides the best possible clinical outcome for the patient.[iv]
Metallic and non-metallic posts
Post materials, once exclusively composed of metal, now vary widely. Posts can be cast or prefabricated, and can be made from a variety of materials, including precious, semi-, or nonprecious metal alloys, zirconia, or carbon, and glass-fibre. Traditionally used cast or fabricated gold alloy, stainless steel or titanium posts have a high modulus of elasticity, and have been considered strong and effective. However, evidence shows that glass, quartz, polyethylene and carbon-reinforced composite fibre posts with lower elasticity may enhance the fracture resistance of ETT when incorporated into a direct composite restoration.[v]
Several studies have indicated that metallic posts demonstrate superior adaptation and reduced root stress in comparison to glass-fibre posts. One of the advantages of metal over ceramic or zirconia is its retrievability in the event of fracture. Stiffer posts and cores can enhance the retention of the coronal restoration and contribute to more uniform stress distribution within the root canal. However, it is important to note that excessive loading can result in catastrophic root fractures.[vi]
Some studies have suggested that fibre reinforced composite (FRC) posts may lead to fewer tooth fractures because they have a similar modulus of elasticity to dentine.[vii] Since their introduction in 1989, they have gained popularity among dental clinicians due to their reliable clinical performance and variety of advantages, such as their mechanical, aesthetic, and elastic properties.
The ferrule effect
One of the most critical factors in the fracture resistance of ETT restored with full crowns is the amount of coronal dentine remaining after preparation for post-placement. A margin of 1.5 to 2 mm healthy coronal tooth structure between the core and the finish line has consistently been proven to be more important in fracture resistance than the post design or type when restoring an ETT.[viii]
A ferrule is defined as a 360-degree collar of crown material, often made of metal, that encircles the external dimensions of a tooth. It lies between the dentine-core interface and the cervical crown margin.[ix] The ferrule effect is the means by which a ferrule, or remaining dentine, helps to manage the stress of forces applied to the restoration.[x]
When a tooth is ferruled, the forces that would exert stress in furcations and roots are dispersed over a wider area, greatly improving the biomechanical strength of a tooth. This effect also decreases the stress in the post and between adhesive interfaces.[xi]
Post and core restorations
While post and core restorations can significantly extend the lifespan of ETT, it is typically considered a last resort for teeth with structural compromise.[xii] The success of post and core restorations requires a complete understanding of the techniques and material characteristics involved.
The ParaPost® system from COLTENE offers a versatile range of fibre posts, metal posts and prefabricated casting post components for any clinical situation. ParaPost®, the first standardised post system, has been the most widely used post in dentistry for over 60 years. Perfect for both direct and indirect restorations, the safety and effectiveness of ParaPost® system has been demonstrated in over 500 studies.
With the right approach and technique, as well as strategic selection of cases, clinicians can successfully extend the lifespan of teeth without enough coronal tissue to support a crown.
For more information, visit https://colteneuk.com/paraposts email info.uk@coltene.com or call 0800 254 5115.
Nicolas Coomber: COLTENE National Account & Marketing Manager
[i] Alenezi AA, Alyahya SO, Aldakhail NS, Alsalhi HA. Clinical behavior and survival of endodontically treated teeth with or without post placement: a systematic review and meta-analysis. J Oral Sci. 2024 Oct 16;66(4):207-214. doi: 10.2334/josnusd.24-0098. Epub 2024 Sep 4. PMID: 39231718.
[ii] Corazza, Pedro Henrique ; Di Domênico, Marielle Bazzo ; Facenda, Júlia Cadorim ; Merlo, Erlon Grando ; Borba, Marcia ; Özcan, Mutlu. Fiberglass versus cast metal posts: a practical review based on mechanical properties. University of Zurich. 2022. Brazillian Dental Science. Braz Dent Sci 2022 Oct/Dec;25 (4): e3442. DOI: https://doi.org/10.4322/bds.2022.e3442
[iii] Alenezi AA, Alyahya SO, Aldakhail NS, Alsalhi HA. Clinical behavior and survival of endodontically treated teeth with or without post placement: a systematic review and meta-analysis. J Oral Sci. 2024 Oct 16;66(4):207-214. doi: 10.2334/josnusd.24-0098. Epub 2024 Sep 4. PMID: 39231718.
[iv] Corazza, Pedro Henrique ; Di Domênico, Marielle Bazzo ; Facenda, Júlia Cadorim ; Merlo, Erlon Grando ; Borba, Marcia ; Özcan, Mutlu. Fiberglass versus cast metal posts: a practical review based on mechanical properties. University of Zurich. 2022. Brazillian Dental Science. Braz Dent Sci 2022 Oct/Dec;25 (4): e3442. DOI: https://doi.org/10.4322/bds.2022.e3442
[v] Alenezi AA, Alyahya SO, Aldakhail NS, Alsalhi HA. Clinical behavior and survival of endodontically treated teeth with or without post placement: a systematic review and meta-analysis. J Oral Sci. 2024 Oct 16;66(4):207-214. doi: 10.2334/josnusd.24-0098. Epub 2024 Sep 4. PMID: 39231718.
[vi] Guilherme Schmitt de Andrade, Guilherme de Siqueira Ferreira Anzaloni Saavedra, Marina Gullo Augusto, Génesis Alfonzo Leon, Hellen Cristina Budel Brandão, João Paulo Mendes Tribst, Amanda Maria de Oliveira Dal Piva, Post-endodontic restorative treatments and their mechanical behavior: A narrative review, Dentistry Review, Volume 3, Issue 1, 2023, 100067, ISSN 2772-5596, https://doi.org/10.1016/j.dentre.2023.100067.
[vii] Guilherme Schmitt de Andrade, Guilherme de Siqueira Ferreira Anzaloni Saavedra, Marina Gullo Augusto, Génesis Alfonzo Leon, Hellen Cristina Budel Brandão, João Paulo Mendes Tribst, Amanda Maria de Oliveira Dal Piva, Post-endodontic restorative treatments and their mechanical behavior: A narrative review, Dentistry Review, Volume 3, Issue 1, 2023, 100067, ISSN 2772-5596, https://doi.org/10.1016/j.dentre.2023.100067.
[viii] Ahmad Yahya K. Assiri, Jilani Saafi, Mohammed M. Al-Moaleem, Vini Mehta. Ferrule effect and its importance in restorative dentistry: A literature Review. Journal of Population Therapeutics & Clinical Pharmacology Nov 2022. DOI: 10.47750/jptcp.2022.977
[ix] Ahmad Yahya K. Assiri, Jilani Saafi, Mohammed M. Al-Moaleem, Vini Mehta. Ferrule effect and its importance in restorative dentistry: A literature Review. Journal of Population Therapeutics & Clinical Pharmacology Nov 2022. DOI: 10.47750/jptcp.2022.977
[x] Mamoun JS. On the ferrule effect and the biomechanical stability of teeth restored with cores, posts, and crowns. Eur J Dent. 2014 Apr;8(2):281-286. doi: 10.4103/1305-7456.130639. PMID: 24966784; PMCID: PMC4054064.
[xi] Guilherme Schmitt de Andrade, Guilherme de Siqueira Ferreira Anzaloni Saavedra, Marina Gullo Augusto, Génesis Alfonzo Leon, Hellen Cristina Budel Brandão, João Paulo Mendes Tribst, Amanda Maria de Oliveira Dal Piva, Post-endodontic restorative treatments and their mechanical behavior: A narrative review, Dentistry Review, Volume 3, Issue 1, 2023, 100067, ISSN 2772-5596, https://doi.org/10.1016/j.dentre.2023.100067.
[xii] Ahmed R, Dubal R. The restoration of structurally compromised endodontically treated teeth: principles and indications of post and core restorations. Dental Update 2025 47:8, 670-676.
