Background: Provisional restorations in fixed prosthodontic rehabilitation are important treatment procedures. Purpose: : The purpose of the present study was to evaluate the marginal and internal fit of polymethyl methacrylate (PMMA) restoration fabricated by Cone Beam Computed Tomography versus extra oral scanning techniques.
Methods: Mandibular right first molar on dental model was prepared. Twenty conventional impressions made using a polyvinylsiloxane (PVS) elastomer for the prepared molar. Impressions for the prepared tooth poured using extra hard dental stone. The models divided for two groups. The 1st group scanned with Extra oral scanner(EOS) .The 2nd group scanned with CBCT. Twenty PMMA crowns were designed on virtual casts and milled. The vertical marginal discrepancy (VMD) was measured by U500x Digital Microscope at twelve locations on each abutment. A total of 240 measurements were made at fixed locations in two groups of 20 specimens.
Results: : It was found that CBCT group recorded statistically non-significant higher vertical marginal gap mean value (26.91 ± 7.11 µm) than EOS group (25.47 ± 6.34 µm) as proven with two-way ANOVA test (p = 0.6062 > 0.05).The internal fit measured using replica technique that revealed CBCT group recorded statistically non-significant higher internal gap mean value (98.97 ± 11.32 µm) than EOS group (90.57± 12.05 µm) as proven with two-way ANOVA test (p = 0.0665 > 0.05).
Conclusions it was found that CAD-CAM fabricated restorations based on EOS or CBCT scanning provided clinically accepted fit for PMMA crowns.