Purpose: When treating an early permanent molar with coronal malformation in children, as in severe molar incisor hypomineralization (MIH) cases, preformed metal crowns (PMCs) are a successful mid- to long-term restorative option. The purpose of this study was to evaluate possible changes in periodontal tissues and subgingival microbiota after PMC placement by way of a split-mouth study.
Methods: Fourteen healthy patients with a mean age of 10.6 (±4.2) years old, attending a university dental clinic, had one MIH severely affected permanent first molar restored with a PMC (study side), while the contralateral relatively healthy tooth was the control. The Turesky plaque index, gingival index (GI), and pocket depth (PD) were assessed, and counts of periodontal pathogens were determined by checkerboard DNA-DNA hybridization at baseline and at the six-month recall.
Results: There were no defective PMCs at either examination time. GI and PD significantly increased statistically in the permanent molars under study from baseline to follow up, as did Porphyromonas gingivalis and Tannerella forsythia counts.
Conclusion: The changes found in periodontal status and specific periodontal pathogens six months after preformed metal crown placement on permanent first molars warrant long-term follow-up to ascertain if these are reversible.