Marginal accuracy of provisional crowns using three material systems and two techniques: A scanning electron...

Area of Science:

• Dental materials science
• Prosthodontics
• Biomaterials engineering

Background:

• Adequate marginal fit of provisional crowns is crucial for periodontal health, dentin sensitivity reduction, and pulp protection.
• Evaluating different provisional crown materials and fabrication techniques is essential for optimizing clinical outcomes.

Purpose of the Study:

• To compare the vertical marginal accuracy of three provisional crown material systems: chemically activated PMMA powder-liquid, light-activated UDMA single paste, and chemically activated Bis-GMA two-paste auto-mix.
• To evaluate the influence of direct versus indirect fabrication techniques on the marginal accuracy of provisional crowns.

Main Methods:

• Forty provisional crowns were fabricated on stainless steel dies using three material systems and two techniques (direct and indirect).
• Marginal discrepancies were measured using scanning electron microscopy (SEM) at x100 magnification.
• Statistical analysis included descriptive statistics, one-way ANOVA, Shapiro Wilk's Test, and Tukey HSD Post Hoc Test.

Main Results:

• The mean marginal discrepancies for direct technique crowns were: Bis-GMA (67.15 µm), UDMA (71.01 µm), and PMMA (84.56 µm).
• The indirect technique with PMMA acrylic resin showed a mean marginal discrepancy of 103.03 µm.
• Bis-GMA composite resin demonstrated the lowest marginal discrepancy among the tested materials using the direct technique.

Conclusions:

• Provisional crowns fabricated with Bis-GMA composite resin (two-paste auto-mix system) exhibited the best marginal accuracy.
• The indirect fabrication technique resulted in superior marginal opening compared to the direct technique for provisional crowns.