Color Stability and Marginal Integrity of Different Interim Restorations.

Objectives: A critical factor in successful treatment in fixed prosthodontics is the quality of an interim restoration. The present study aims to investigate the color stability and marginal integrity of interim restoration fabricated by three different techniques after thermal aging.
Methods: Sixty newly extracted non-carious anterior teeth were prepared for ceramic crowns. After preparation, the teeth were randomly equally divided into three groups (20/group). The first group was digitally scanned by CAD software, and interim designs were constructed. The interim restorations were milled using a Planmeca milling machine. The other two groups of interim crowns were fabricated manually using Bis Acryl and acrylic Snap material (Parkell). All examined interim crowns were cemented using RelyX Temp NE - Noneugenol Temporary Zinc Oxide Cement (3M). The shade was evaluated using digital spectrophotometer (VITA Easyshade V) and the marginal integrity measurements were examined using a non-contact 3D profilometer. The examined teeth were subjected to artificial aging using a thermocycling machine dwelling for 5000 cycles (equivalent to 6 clinical months) at 5°C and 55°C. All samples ' color stability and marginal integrity were measured before and after thermal aging. ANOVA test was used to compare the marginal differences between the examined groups.
Results: After six clinical months, the results showed a significant difference in marginal integrity between the three groups. Bis Acryl interim crowns displayed the lowest change in marginal integrity, while Acrylic interim crowns showed the most significant changes. The manual Acrylic interim material revealed significantly more color change (30%) than the other examined groups. The CAD/CAM interim group was the most color-stable group.
Conclusions: Within the limitation of the present investigation, the manually fabricated interim crowns of the Bis Acryl proved superior to Milled CAD/CAM and Acrylic interim crowns. The milled CAD/CAM showed more color stability than the manually fabricated groups