Efficacy of Preformed Metal Crowns Vs. Amalgam Restorations in Primary Molars: A systematic Review.

Article title: Efficacy of Preformed Metal Crowns Vs. Amalgam Restorations in Primary Molars: A systematic Review.
Author(s):Randall, Matthias, Vrijhoef, Wilson
Journal: JADA
Volume (number): vol 131
Month, Year: March, 2000
Major topic: Metallic restorative materials for primary molars
Minor topics: Restorative materials
Type of Article: Review of literature
Main Purpose: To test the hypothesis that amalgams and SSCs share equal clinical success rates in primary molars.
Overview of method of research: 10 studies were chosen that met the inclusion criteria of including a clinical comparison of the longevity or success rate of SSCs in primary molars vs amalgam control in primary molars and the data of the studies was available for comparing treatment outcomes. Statistical analysis was performed to determine the odds ratio and a 95% confidence interval.
Findings:
The review did not support the hypothesis of similar success rates for PMCs and amalgams. The evidence supports better clinical results for SSCs on multi-surface cavities vs amalgam restorations.

Key points/Summary :
Close proximity of the mesial pulp horn to the mesial wall of the primary 1st molar make it difficult to obtain adequate mechanical retention without exposing the pulp.
There were 35 articles that addressed this subject, but only 10 met the criteria, so there is a larger pool of research than this article represents.
Most of the restorations in the studies were performed in hospital pediatric dental clinics or dental schools.
The main reason for SSC failure was loss of the crown requiring it to be recemented
The main reason for amalgam failure was fracture and secondary caries.
Amalgams failed between 1.5 and 9 times for every SSC that failed.
Every study demonstrated SSCs to be a better restoration for multi-surface lesions.
Most of the studies used SSCs for larger lesions, which may allow interpretation that they were even more successful than indicated.
The authors surmised that the Braff study--which showed the least success for SSCs--used a non-anatomical preformed crown that required extensive trimming and adjustment, which could be the cause of some failures.
4 studies excluded failures of pulpal inflammation if they didn’t think the inflammation was related to the restoration. In the other studies, pulpal inflammation was considered a failure.
The authors recommended that studies done looking at newer cements for SSCs
Assessment of article: You only have to see one failed Cl II amalgam know that you should do an SSC instead. It’s good that this was in JADA because I think a lot of general dentists are treating primary teeth like small permanents (yeah that’s a cliche’).