BACKGROUND: It is unknown if resin-based composite can be placed on top of mineral trioxide aggregate (MTA) immediately after placement of the MTA. The authors aimed to measure the bond strength of a resin-based composite to white MTA (WMTA) with different bonding strategies at different intervals. METHODS: The authors bonded resin-based composite to MTA with three bonding protocols (n = 45 per group) (group 1, total-etching adhesive; group 2, two-step self-etching adhesive; or group 3, one-step self-etching adhesive), immediately (subgroup A), 45 minutes (subgroup B) or 24 hours (subgroup C) after placement of the MTA. The authors measured shear bond strength by means of a universal testing machine and performed statistical analysis of the data by means of two-way and one-way analysis of variance (P < .05). RESULTS: In all three groups, subgroup A demonstrated greater bond strengths than the other subgroups. Group/subgroup 3/A demonstrated the highest bond strength (mean [standard deviation] 49.2 [2.1] megapascals), which was significantly higher than that in all other groups (P < .05). This was followed by group/subgroup 1/A (40.2 [2.5] MPa), 2/A (38.4 [1.3] MPa) and 1/B (38.5 [1.91] MPa). The lowest bond strength was shown by group/subgroup 2/C (14.7 [1.90] MPa). There was a significant difference between the two-step and one-step self-etching adhesives at all three intervals (P < .05). CONCLUSIONS: Within the limitations of this study, the representative one-step self-etching adhesive demonstrated the strongest bond to WMTA immediately after fabrication of MTA samples. CLINICAL IMPLICATIONS: One-step self-etching adhesive may be used to bond resin-based composite to WMTA immediately after placement, thereby offsetting the need for a second appointment for permanent restoration.
BACKGROUND: It is unknown if resin-based composite can be placed on top of mineral trioxide aggregate (MTA) immediately after placement of the MTA. The authors aimed to measure the bond strength of a resin-based composite to white MTA (WMTA) with different bonding strategies at different intervals. METHODS: The authors bonded resin-based composite to MTA with three bonding protocols (n = 45 per group) (group 1, total-etching adhesive; group 2, two-step self-etching adhesive; or group 3, one-step self-etching adhesive), immediately (subgroup A), 45 minutes (subgroup B) or 24 hours (subgroup C) after placement of the MTA. The authors measured shear bond strength by means of a universal testing machine and performed statistical analysis of the data by means of two-way and one-way analysis of variance (P < .05). RESULTS: In all three groups, subgroup A demonstrated greater bond strengths than the other subgroups. Group/subgroup 3/A demonstrated the highest bond strength (mean [standard deviation] 49.2 [2.1] megapascals), which was significantly higher than that in all other groups (P < .05). This was followed by group/subgroup 1/A (40.2 [2.5] MPa), 2/A (38.4 [1.3] MPa) and 1/B (38.5 [1.91] MPa). The lowest bond strength was shown by group/subgroup 2/C (14.7 [1.90] MPa). There was a significant difference between the two-step and one-step self-etching adhesives at all three intervals (P < .05). CONCLUSIONS: Within the limitations of this study, the representative one-step self-etching adhesive demonstrated the strongest bond to WMTA immediately after fabrication of MTA samples. CLINICAL IMPLICATIONS: One-step self-etching adhesive may be used to bond resin-based composite to WMTA immediately after placement, thereby offsetting the need for a second appointment for permanent restoration.