Root canal treatment is a common dental procedure, although root canal preparation is considered to result in weakening of the tooth structure. However, there is uncertainty over the comparative clinical performance of crowns or conventional restorations. This updated review aims to assess the effects of restoration of endodontically treated teeth (with or without post and core) by crowns versus conventional filling materials.

Methods

Searches were conducted in the Cochrane Oral Health Group’s Trials Register, Cochrane CENTRAL, Medline, Embase, CINAHL, LILACS, the reference lists of articles and ongoing trials registries . Randomised controlled trials (RCTs) or quasi-randomised controlled trials, including parallel group design, split-mouth trials, cluster trials and randomised patient preference trials.

Results

• Only 1 trial involving 117 patients could be included.
• The trial was considered to be at high risk of performance, detection and attrition bias.
• Premolar tooth restored with a carbon fibre post, were randomised to either a full coverage metal-ceramic crown or direct adhesive composite restoration. None experienced a catastrophic failure (i.e. when the restoration cannot be repaired), although only 104 teeth were included in the final, three-year assessment.
• There was no clear difference between the crown and composite group and the composite only group for non-catastrophic failures of the restoration.
• The quality of the evidence for these outcomes is very low.
• There was no evidence available for any of our secondary outcomes: patient satisfaction and quality of life, incidence or recurrence of caries, periodontal health status, and costs.

Conclusions

The authors concluded:

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

Comments

This Cochrane review updates the 2012 version (Dental Elf – 18^th May 2012). Despite an extensive search no new trials were identified so the conclusions are unchanged. Earlier this year we highlighted a rapid review of this question from the Canadian Agency for Drugs and Technologies in Health (Dental Elf – 3^rd Aug 2015). They considered a broader range of evidence (3 systematic reviews an 4 non-randomised studies). The highest quality review included in their deliberations was the earlier version of this Cochrane review, the other two systematic review included studies designs other than RCTs. The Canadian review also highlighted that the studies in their review did not evaluate tooth survival based on the amount of its destruction which may play a major role in tooth survival. However, they concluded that the short term survival (2 to 3 years) of root canal treated teeth restored with crowns or direct fillings is comparable.

Links

Sequeira-Byron P, Fedorowicz Z, Carter B, Nasser M, Alrowaili EF. Single crowns versus conventional fillings for the restoration of root-filled teeth. Cochrane Database of Systematic Reviews 2015, Issue 9. Art. No.: CD009109. DOI: 10.1002/14651858.CD009109.pub3.

Cochrane Oral Health Group – Should you use a crown or a filling to restore a root-filled tooth?

Dental Elf – 3^rd Aug 2015 – Crowns improved survival of root treated teeth suggests review

Dental Elf – 18^th May 2012 – Insufficient evidence to support or refute the effectiveness of conventional fillings over crowns for the restoration of root filled teeth