Preformed metal crowns for decayed primary molar teeth

Summary

Preformed metal crowns for managing decayed primary molar teeth in children Management of decay in primary molar teeth conventionally involves removal of decayed tooth and placement of a preformed metal crown (also known as a stainless steel crown) to completely cover the tooth or placement of a filling (a soft material which is placed in the hole and hardened) to restore the tooth. Preformed metal crowns are recommended by specialists in children’s dentistry for the management of these teeth when they are affected by moderate to advanced tooth decay. We were unable to find any high quality research evidence either for or against this recommendation. No randomised control trials were found which compared removal of decay followed by placement of a preformed metal crown with removal of decay followed by placement of a filling material or no treatment.
However, there is some evidence from clinical studies of poor to medium quality that preformed metal crowns may last longer than fillings for these teeth. Confirmation of this will require well controlled clinical trials.

Abstract

Background

Preformed metal crowns (PMCs) are recommended by the British Society of Pediatric Dentistry (BSPD) for restoring badly broken down primary molar teeth. However, few dental practitioners adopt this technique in clinical practice, citing cost and clinical difficulty as reasons for this. Whilst there is a subjective impression by clinical academics that PMCs provide a more durable restoration than filling materials, there appears to be little evidence within the literature to support this.

Objectives

The primary aim of this systematic review was to compare clinical outcomes for primary molar teeth restored using PMCs compared to those restored with filling materials.

Search strategy

The literature was searched using: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2005, Issue 3); MEDLINE (1966 to August 2005); EMBASE (1980 to August 2005); System for Information on Grey Literature in Europe (SIGLE) (1976 to August 2005). Relevant publications’ reference lists were reviewed for relevant articles. The most recent search was carried out on 24 August 2005.

Selection criteria

Randomised controlled trials (RCTs) that assessed the effectiveness of PMCs compared with filling materials or where there had been no treatment in children with untreated tooth decay in one or more primary molar teeth.

Data collection and analysis

Two review authors independently assessed the title and abstracts for each article from the search results to decide whether it was likely to be relevant. Full papers were obtained for relevant articles and all three review authors studied these.

Main results

Forty-seven records were retrieved by the search strategies of which some were duplicates. Of these, 14 studies were scrutinized. No studies met the inclusion criteria and six studies were excluded from the review as they were either retrospective in design or reported as prospective outcomes but not randomised. No data were available for extraction and analysis and therefore, no conclusion could be made as to whether PMCs were more successful than filling materials for restoring primary molar teeth.

Authors’ conclusions

No RCTs were available for appraisal. Whilst this technique is recommended by the BSPD for use in clinical practice, the evidence to support this is not strong, consisting mainly of case reports and uncontrolled studies. It is important that the absence of evidence for PMCs is not misinterpreted as evidence for their lack of efficacy.
There is a strong need for prospective RCTs comparing PMCs and fillings for managing decayed primary molar teeth. The lower levels of evidence that have been produced, however, have strength in that the clinical outcomes are consistently in favour of PMCs, despite many of the studies placing PMCs on the most damaged of the pair of teeth being analysed .