講演情報
[P-51（E）]Zirconia Tube and Short Fiber-Reinforced Composite Resin Foundations Improve Fracture Resistance of Endodontically Treated Premolars Restored with CAD/CAM Resin Crowns
*Yunlong Wang1, Wataru Komada1, Shinya Oishi1, Daiki Kondo1, Kenji Fueki1 (1. Institute Science Tokyo)
[Purpose]
Composite resin core build-up with a glass-fiber post is widely used for restoring endodontically treated teeth because its elastic modulus approximates that of dentin. However, cervical stress concentration can still lead to fracture or debonding, especially when the remaining structure is limited. To reinforce this vulnerable region, a zirconia tube–reinforced core build-up system was developed 1). Short fiber–reinforced composite resin (SFRC) has also shown potential to improve fracture resistance, but evidence remains limited when combined with CAD/CAM resin crowns. This pilot study aimed to evaluate the effects of different core build-up systems on the fracture resistance of endodontically treated premolars with flared canals restored using CAD/CAM resin crowns.
[Method]
Bovine roots were standardized to simulate premolars with flared canals. Four core build-up systems were tested: composite resin only (RC), short fiber–reinforced composite resin (SFC), composite resin with a zirconia tube (ZC), and short fiber–reinforced composite resin with a zirconia tube (ZSFC). All specimens received CAD/CAM resin crowns (n = 5 per group). Fracture testing was performed using a universal testing machine at 1 mm/min until failure, and the maximum load was recorded. Data were analyzed using one-way ANOVA and Tukey’s test (α = 0.05).
[Results and considerations]
ZSFC exhibited significantly higher fracture resistance than RC and SFC (P < 0.05). ZC also showed significantly greater strength than RC (P < 0.05). No significant differences were detected between ZC and ZSFC or between SFC and RC or ZC (P > 0.05). These findings suggest that zirconia tube reinforcement improved fracture resistance more effectively than short fiber reinforcement alone in premolars with flared canals restored with CAD/CAM resin crowns. Zirconia tube–based foundations may therefore be a promising option for reinforcing structurally compromised teeth.
[Reference]
1) Kondo D, Komada W, Oishi S, et al. Surface strain at the cervical area and fracture strength of flared root canals reinforced using a zirconia tube and glass-fiber post. J Dent Sci 2024;19:1571–1577.
Composite resin core build-up with a glass-fiber post is widely used for restoring endodontically treated teeth because its elastic modulus approximates that of dentin. However, cervical stress concentration can still lead to fracture or debonding, especially when the remaining structure is limited. To reinforce this vulnerable region, a zirconia tube–reinforced core build-up system was developed 1). Short fiber–reinforced composite resin (SFRC) has also shown potential to improve fracture resistance, but evidence remains limited when combined with CAD/CAM resin crowns. This pilot study aimed to evaluate the effects of different core build-up systems on the fracture resistance of endodontically treated premolars with flared canals restored using CAD/CAM resin crowns.
[Method]
Bovine roots were standardized to simulate premolars with flared canals. Four core build-up systems were tested: composite resin only (RC), short fiber–reinforced composite resin (SFC), composite resin with a zirconia tube (ZC), and short fiber–reinforced composite resin with a zirconia tube (ZSFC). All specimens received CAD/CAM resin crowns (n = 5 per group). Fracture testing was performed using a universal testing machine at 1 mm/min until failure, and the maximum load was recorded. Data were analyzed using one-way ANOVA and Tukey’s test (α = 0.05).
[Results and considerations]
ZSFC exhibited significantly higher fracture resistance than RC and SFC (P < 0.05). ZC also showed significantly greater strength than RC (P < 0.05). No significant differences were detected between ZC and ZSFC or between SFC and RC or ZC (P > 0.05). These findings suggest that zirconia tube reinforcement improved fracture resistance more effectively than short fiber reinforcement alone in premolars with flared canals restored with CAD/CAM resin crowns. Zirconia tube–based foundations may therefore be a promising option for reinforcing structurally compromised teeth.
[Reference]
1) Kondo D, Komada W, Oishi S, et al. Surface strain at the cervical area and fracture strength of flared root canals reinforced using a zirconia tube and glass-fiber post. J Dent Sci 2024;19:1571–1577.
