The effect of working time on the displacement of Biodentine() beneath prefabricated stainless steel crown: a laboratory study.

OBJECTIVE: To investigate the displacement of Biodentine() following cementation of stainless steel crowns (SSC) with glass-ionomer cement (GIC) on plastic deciduous teeth prepared for pulpotomy. METHODS: Twenty plastic teeth with prepared occlusal cavities were divided into four groups and had Biodentine() placed as a mock pulpotomy agent. The pulp chamber was filled with freshly mixed Biodentine() then a GIC-loaded SSC was seated on the tooth using a standardized seating force for periods of: 1 min (Group 1); 2 min (Group 2), 3 min (Group 3) and 6 min (Group 4) after mixing. After 24 h at 37 degrees C and 90% humidity, the crowns were sectioned mesio-distally and standardized digital photographs taken. Image analysis software was used to determine the ratio of the surface area of displaced Biodentine() relative to the surface area of the pulp chamber. The thinnest section of the remaining Biodentine() was measured. RESULTS: The lowest values of Biodentine() displacement and the highest values of remaining Biodentine() thickness were associated with Group 4. There were no significant differences between the results in Group 3 and Group 4. CONCLUSION: Within the limitations of this in vitro study, a GIC-loaded SSC can be seated on Biodentine() placed into a pulp chamber 3 min after mixing.