Influence of Cavity Design and Fabrication Technique on Fracture Resistance of PFM Endocrowns in Endodontically Treated Mandibular Molars: An In Vitro Study
Design and Fabrication Effects on PFM Endocrowns
Abstract
Background:
Endodontically treated teeth (ETT) are structurally weakened due to loss of tooth structure and altered biomechanical properties. Restoration of such teeth remains a clinical challenge. Endocrowns have emerged as a conservative alternative that utilizes adhesive bonding and intracoronal retention. However, factors such as cavity design and fabrication technique significantly influence their fracture resistance.
Materials and Methods:
Forty extracted human mandibular molars were selected, cleaned, and standardized. Endodontic treatment was performed using conventional techniques. The samples were divided into four groups (n=10) based on cavity design (conventional and buccal extension) and fabrication technique (conventional impression and CAD/CAM). PFM endocrowns were fabricated accordingly and cemented using glass ionomer cement. Fracture resistance was evaluated using a universal testing machine under compressive load. Statistical analysis was performed using one-way ANOVA and Tukey post hoc test (p < 0.05).
Results:
The buccal extension CAD/CAM group showed the highest fracture resistance (1009.50 ± 9.48 N), followed by normal CAD/CAM (951.45 ± 11.18 N), buccal extension impression (687.92 ± 9.93 N), and normal impression groups (553.05 ± 10.77 N). The differences were statistically significant (p = 0.000).
Conclusion:
Both cavity design and fabrication technique significantly influence fracture resistance. Buccal extension combined with CAD/CAM fabrication provides superior biomechanical performance and may be recommended for clinical application.
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