Marginal Integrity, Internal Adaptation and Compressive Strength of 3D Printed, Computer Aided Design and Computer Aided Manufacture and Conventional Interim Fixed Partial Dentures

The aim was to investigate the marginal fit, internal adaptation and compressive strength of SLA provisionals (SLA) in comparison to CAD-CAM and conventional (CONV) interim fixed partial dentures (FPDs). Thirty interim FPDs were fabricated using CAD-CAM technology (CAD-CAM blocks Ceramill TEMP, PMMA), conventional molding technique (CONV) (TrimPlus, PMMA) and Stereolithography (SLA) method (Form 2, Formlabs, PMMA) (n = 10). Internal adaptation (occlusal, corona', middle and cervical) and marginal integrity (inner and outer edge) was assessed using micro-computerized tomography (Micro-CT). The failure and compressive strength was assessed by application of a static load at a crosshead speed of 1 mm/min until fracture. Data was analysed using ANOVA and multiple comparisons test. The maximum and minimum marginal mis-fit was for CONV (283.3 +/- 98.6 nm) and CAD-CAM (68.2 +/- 18.1 mu m) groups. CAD-CAM (68.2 +/- 18.1 mu m) and SLA (84.7 +/- 27.5 mu m) provisionals showed comparable marginal mis-fit (p > 0.05). The mean failure load was significantly higher (p < 0.05) in CAD-CAM (687.86 +/- 46.72 N), compared to SLA (534.8 +/- 46.1 N) and CONV (492.7 +/- 61.8 N) samples. Compressive strength for CAD-CAM (2.44 +/- 0.27 MPa) samples was significantly higher (p < 0.05) than SLA (1.80 +/- 0.15 MPa) and CONV (1.65 +/- 0.20 MPa) groups. Marginal fit and internal adaptation of SLA printed FPDs was comparable to CAD-CAM interims. Compressive strength of the SLA interims FPDs can withstand intra-oral loads.