Preliminary Microleakage Comparison of Bulk-Fill Restoratives and Preformed Metal Crowns in Pulpotomized Primary Molars.

The purpose of this in vitro study was to compare the microleakage of bulk-fill restoratives to the gold standard, preformed metal crowns (PMCs), in pulpotomized primary molars. Fifty-four extracted primary molars were selected, ensuring three intact walls and at least two-thirds root length. After caries removal and pulpotomy procedures, intermediate restorative material (IRM) was placed in the pulp chambers. Teeth were then randomly divided according to the final restoration into six groups (N equals nine): Group A-Activa (glass ionomer liner, etching, bonding); Group B-Tetric N-Ceram Bulk-Fill composite (liner, etching, bonding); Group C-Cention N (liner, etching, bond- ing); Group D-Cention N (liner); Group E-IRM; and Group F-PMCs (control). Specimens underwent 500 thermocycles and 24-hour immersion in one percent methylene blue dye at 37 degrees Celsius. Microleakage was assessed after mesio-distal sectioning using Kruskal-Wallis and Dunn's post hoc tests (P<0.05). Group A-Activa (mean rank equals 18.28) and Group C-Cention N, (mean rank equals 20.5) showed signifi- cantly lower leakage scores than Group E-IRM (mean rank equals 41.5; P=0.012 and 0.036, respectively). Group A -Activa had the highest proportion of leakage-free samples (44.4 percent). Differences between Bulk-Fill materials groups and Group F-PMCs were statistically insigni- ficant. Microleakage trends decreased in order from Group A-Activa to -C Cention N to B-Tetric N-Ceram Bulk-Fill composite to D- Cention N (liner) to F-PMCs. These preliminary in vitro findings provide evidence for one aspect of restorative success, suggesting that bulk-fill restoratives, particularly Activ and Cention N with adhesive, may be promising alternatives to preformed metal crowns for restoring pulpotomized primary molars for microleakage resistance. However, further parameter testing and clinical research are needed to confirm these findings.