Association between lesion depth and placement technique with failures requiring extraction of preformed metal crowns in primary molars. A retrospective study.

Purpose: The aim of the present study was to evaluate the factors associated with failure requiring extraction after placement of preformed metal crowns (PMCs) in primary molars. Radiographic caries depth at baseline (initial/moderate and severe) and placement technique (Conventional and Hall technique) and other patient-related variables were analysed.

Methods: Clinical and radiographic records from children aged 2-10 years who had at least one primary molar treated with PMCs between 2011 and 2019 were evaluated. Chi-square test, Fisher exact tests and logistic regression analysis (α = 5%) were performed to verify the relationship between the primary outcome and categorical variables (caries depth, restorative teachnique, jaw, tooth type and gender).

Results: A total of 244 teeth treated in 165 children were included in the analysis. A total of 18 failures were observed (7.4%), of which 17 were in deep caries lesions and in which 15 had the PMC placed according to the conventional technique. Both caries lesion depth and restorative technique were associated with treatment failure (p < 0.05).

Conclusion: Taking into account the limitations of this retrospective study, treatment failures requiring extraction occurred more often in deep caries lesions when treated with preformed metal crowns (PMCs) following the conventional technique when compared to the Hall Technique.