Root canal filling is a regular dental procedure. However root filled teeth can be weaker than healthy ones so restoration of these teeth can prove challenging. The aim of this Cochrane review was to assess whether restoring endodontically treated teeth (with or without post and core) using crowns or conventional filling materials was more effective.

What did they do

The Cochrane Oral Health Group’s Trials Register, Cochrane CENTRAL, Medline , Embase  CINAHL and LILACS  databases  together with the reference lists of articles as well as ongoing trials registries were searched.Randomised controlled trials (RCTs) or quasi-randomised controlled trials in adult permanent teeth were included. Two review authors independently assessed trial quality and extracted data.

 They found

• Only one trial judged to be at high risk of bias due to missing outcome data, was included. 117 participants with a root filled premolar tooth restored with a carbon fibre post, were randomised to either a full coverage metal-ceramic crown or direct adhesive composite restoration.
• At 3 years there was no reported difference between the non-catastrophic failure rates in both groups.
• De-cementation of the post and marginal gap formation occurred in a small number of teeth.

 They concluded

There is insufficient evidence to support or refute the effectiveness of conventional fillings over crowns for the restoration of root filled teeth. Until more evidence becomes available clinicians should continue to base decisions on how to restore root filled teeth on their own clinical experience, whilst taking into consideration the individual circumstances and preferences of their patients.

Fedorowicz Z, Carter B, de Souza RF, de Andrade Lima Chaves C, Nasser M, Sequeira-Byron P. Single crowns versus conventional fillings for the restoration of root filled teeth. Cochrane Database of Systematic Reviews 2012, Issue 5. Art. No.: CD009109. DOI: 10.1002/14651858.CD009109.pub2.