IADR Abstract Archives
Retention Strength of Zirconia Crowns in Pediatric Dentistry
Objectives: To evaluate and compare the tensile bond strengths of luting agents used in conjunction with zirconia crowns
To examine the difference in retentive strength of stainless steel crowns and zirconia crowns.
Methods: Three groups of 20 human premolar teeth were prepared for passive fitting zirconia and stainless steel crowns (SSCs). Each tooth was mounted in die stone to provide an anchor for the tensile forces. Two different types of cements were used: resin modified glass-ionomer cement (RMGIC) and self-adhesive resin cement (RC) . The cemented crowns were stored in water at 37°C for 24 h prior to executing a tensile pull-off force at a strain rate of 5mm/min. Retention strength was calculated using mass (kg) divided by the surface area of each crown (cm2 ). (Retentive Strength = kg/cm2) The failure loads and retentive strengths were modeled and compared by a one-way ANOVA and Newman-Keuls Multiple comparison test (p>0.05).
Results: There were no significant differences between the two types of cement when used with full zirconia crowns; however, a significant difference was discovered in this study. The modulus ranking shows that RC had a higher retentive strength when compared to RMGIC using zirconia crowns, but retentive strengths for SSCs using RMGIC was still significantly higher (Figure). Mode of failure was also determined. These parameters were defined as adhesive to dentin or enamel, cohesive of cement to crown, or a mixed pattern. Mode of failure occurring most often was adhesive to dentin, meaning the crown failed at the dentin/enamel – cement interface. However, other types of failures were observed.
Conclusions: Stainless Steel crowns cemented with RMGIC still possess the highest retentive strength when used as a luting agent, thus the gold standard for many years continues to be the superior restoration for multi-surface decay in pediatric dentistry.
To examine the difference in retentive strength of stainless steel crowns and zirconia crowns.
Methods: Three groups of 20 human premolar teeth were prepared for passive fitting zirconia and stainless steel crowns (SSCs). Each tooth was mounted in die stone to provide an anchor for the tensile forces. Two different types of cements were used: resin modified glass-ionomer cement (RMGIC) and self-adhesive resin cement (RC) . The cemented crowns were stored in water at 37°C for 24 h prior to executing a tensile pull-off force at a strain rate of 5mm/min. Retention strength was calculated using mass (kg) divided by the surface area of each crown (cm2 ). (Retentive Strength = kg/cm2) The failure loads and retentive strengths were modeled and compared by a one-way ANOVA and Newman-Keuls Multiple comparison test (p>0.05).
Results: There were no significant differences between the two types of cement when used with full zirconia crowns; however, a significant difference was discovered in this study. The modulus ranking shows that RC had a higher retentive strength when compared to RMGIC using zirconia crowns, but retentive strengths for SSCs using RMGIC was still significantly higher (Figure). Mode of failure was also determined. These parameters were defined as adhesive to dentin or enamel, cohesive of cement to crown, or a mixed pattern. Mode of failure occurring most often was adhesive to dentin, meaning the crown failed at the dentin/enamel – cement interface. However, other types of failures were observed.
Conclusions: Stainless Steel crowns cemented with RMGIC still possess the highest retentive strength when used as a luting agent, thus the gold standard for many years continues to be the superior restoration for multi-surface decay in pediatric dentistry.
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