endo newsletter ferrule

This month’s Endo Newsletter topic: Benefit of Ferrule or Post in Endodontically Treated Teeth

Over the years, there has been a great deal of discussion about how best to restore endodontically treated teeth, especially with regard to the need for a post. Some clinicians maintain that the role of a ferrule (Figure 2) is more important than that of the post, while others feel strongly that posts enhance the survival of endodontically treated teeth.

Unfortunately, no large randomized prospective study has adequately addressed this question. The solution, then, is a systematic review of similar, relatively small studies, with the findings of those that meet the preset inclusion criteria combined. The papers are critically analyzed, using methods decided upon prior to initiation of the review.

Naumann et al from Charité-Universitätsmedizin Berlin, Germany, sought to answer the question whether restoration with a ferrule or a post made a difference for survival of endodontically treated teeth. In their systematic review, they used the “PICO” process to obtain the best evidence:

  • P — patient: adults with sufficient endodontic treatment needing dentine core buildup
  • I — intervention: postendodontic treatment using posts, with or without ferrule support
  • C — comparison: postendodontic treatment without posts, with or without ferrule support
  • O — outcome: tooth and/or restoration survival

The inclusion criteria called for pro- spective human studies with observation times ≥5 years. Of nearly 2600 identified articles, only 8 met the strict inclusion criteria: 7 randomized controlled trials and 1 prospective clinical trial. Follow-ups in the 8 studies, which included a total of 1932 teeth in 1570 patients, ranged from 5 to 17 years. A common problem with most studies was that the reevaluation rate dropped the longer the observation duration lasted, to the point where only 30% to 40% of patients were available after 17 years.

The authors concluded that failure risk increases with the number of missing cavity walls, and if there are 4 remaining cavity walls, there is no justification for insertion of a post. Some studies also indicated no need for a post when there were 3 and 2 walls remaining, especially where resin composite core buildups were completed prior to single crowns, provided that a ferrule of 1.5 mm to 2 mm was present on the remaining walls.


Overall, most included studies failed to show a positive effect for posts. Therefore, only endodontically treated teeth without cavity walls might benefit from post placement. With little clinical evidence available about the influence of the tooth’s location in the dental arch, clinicians should use their own judgment.

Naumann M, Schmitter M, Frankenberger R, Krastl G. “Ferrule comes first. Post is second!”
Fake news and alternative facts? A systematic review. J Endod 2017;doi:10.1016/j.joen. 2017.09.020.