Comparative study of marginal adaptation and mechanical properties of CAD/CAM versus dual polymerized interim fixed dental prosthesis

Marwa Eltayeb I Elagra, Yousria Shalaby, Moustafa Fakhry Khalil, Nagiub ElFawal

Saudi Journal of Oral Sciences 2014 1(2):71-78

Background: With the advent of new interim crown materials, it has become imperative to evaluate its strength in order to select the appropriate interim crown and partial fixed dental prosthesis material. Aim: The purpose of this in vitro study was to compare marginal adaptation, wear resistance, and fracture resistance of a computer-aided design/computer-aided manufacturing (CAD/CAM) versus a dual polymerized interim fixed dental prosthesis (FDP). Materials and Methods: Twenty models were randomly allocated into two equal groups (I and II). Group (I) received 10 CAD/CAM fabricated interim FDP (CAD-Temp) and Group (II) received 10 directly fabricated interim FDP using a dual polymerized material (TempSpan). All specimens were stored before testing. Marginal adaptation was tested using stereomicroscope and image analyzing software to measure the amount of marginal gap. For wear resistance test, all specimens were subjected to mechanical tooth brushing. Stereomicroscope and image analyzing software were used to measure the difference in height before and after tooth brushing. Specimens were subjected to cyclic loading; specimens intact from defects were then loaded to fracture. Data were analyzed using Student's T- test, Mann Whitney test and Fisher exact test (α = 0.05). Results: CAD-Temp (15.026 ± 4.340 μm) showed significantly higher marginal adaptation than TempSpan (145.418 ± 25.365μm)(P < 0.001). The wear resistance of CAD-Temp (7.3322 ± 0.99853 μm) was significantly higher than TempSpan (22.3165 ± 2.35459 μm) (P < 0.001). The fracture resistance of CAD-Temp (605.1 ± 31.718N) was also significantly higher than that of TempSpan (225.76 ± 32.469N) (P < 0.001). Conclusions: CAD/CAM fabricated interim restorations have better marginal adaptation, wear resistance and fracture resistance than dual polymerized interim restorations hence, might withstand longer duration in the oral cavity.

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