IADR Abstract Archives
Crown Retention Strength and Ion Release of Bioactive Cements
Objectives: To measure crown retention strength of zirconia copings cemented with bioactive cements following thermocycling and calcium and fluoride release from bioactive cements
Methods: 32 human molars were prepared to uniform dimensions (22° total taper and 1.5mm). The surface area of the preparations was calculated with digital microscopy. Teeth were scanned with a True Definition (3M) intraoral scanner. Individual zirconia copings (Bruxzir, Glidewell) were milled and sintered then airborne-particle abraded with 50 micron alumina (30Psi). The crowns (n=8) were cemented with either a bioactive cement (Activa Bioactive Cement; PulpDent, Ceramir; Doxa, or Theracem; Bisco), or a reference resin-modified glass-ionomer (RMGI) cement (RelyX Luting Plus; 3M ESPE). No primers were used. Crowns were self-cured under 2.5kg, stored in PBS solution (48hr, 37C) and thermocycled (10,000cycles, 5-500C, 30sec dwell time). Specimens were loaded in tension (crosshead speed 0.5mm/min) until debonding. 1.5mmx15mm(dia) specimens (n=5) were prepared from each cement and self-cured. The specimens were placed in 50mL of deionized water for 7 days. A 5mL aliquot was removed from each container and fluoride and calcium ion content was measured with a ion specific probe (sension4). Data were compared with a 1-way ANOVA and Tukey analysis (alpha=0.05).
Results: There were significant differences between cements for crown retention strength and fluoride and calcium ion release (p<0.01). Mean +/- SD are presented below and different letters represent significantly different groups.
Conclusions: The bioactive cements tested in this study produced statistically similar tensile crown retention as a reference RMGI cement. Theracem and Ceramir demonstrated more calcium release than the RMGI cement and all bioactive cements released less fluoride than the RMGI cement.
Methods: 32 human molars were prepared to uniform dimensions (22° total taper and 1.5mm). The surface area of the preparations was calculated with digital microscopy. Teeth were scanned with a True Definition (3M) intraoral scanner. Individual zirconia copings (Bruxzir, Glidewell) were milled and sintered then airborne-particle abraded with 50 micron alumina (30Psi). The crowns (n=8) were cemented with either a bioactive cement (Activa Bioactive Cement; PulpDent, Ceramir; Doxa, or Theracem; Bisco), or a reference resin-modified glass-ionomer (RMGI) cement (RelyX Luting Plus; 3M ESPE). No primers were used. Crowns were self-cured under 2.5kg, stored in PBS solution (48hr, 37C) and thermocycled (10,000cycles, 5-500C, 30sec dwell time). Specimens were loaded in tension (crosshead speed 0.5mm/min) until debonding. 1.5mmx15mm(dia) specimens (n=5) were prepared from each cement and self-cured. The specimens were placed in 50mL of deionized water for 7 days. A 5mL aliquot was removed from each container and fluoride and calcium ion content was measured with a ion specific probe (sension4). Data were compared with a 1-way ANOVA and Tukey analysis (alpha=0.05).
Results: There were significant differences between cements for crown retention strength and fluoride and calcium ion release (p<0.01). Mean +/- SD are presented below and different letters represent significantly different groups.
Conclusions: The bioactive cements tested in this study produced statistically similar tensile crown retention as a reference RMGI cement. Theracem and Ceramir demonstrated more calcium release than the RMGI cement and all bioactive cements released less fluoride than the RMGI cement.