Evaluation of Marginal Fit of CAD/CAM Crowns Using Different Preparation Protocols
Objectives: The purpose of this study was to analyze the marginal fit of CAD/CAM crown restorations manufactured with the CEREC 3D/MC Milling systems using two different occlusal preparation protocols; curved and flat surface. Methods: Twenty-six pre-molar typodont plastic teeth were divided into two groups (n=13) according to the occlusal curvature of the tooth preparation. Control group (G1): Curved occlusal and G2: Flat occlusal surface. All teeth received a full crown preparation respecting the assigned occlusal curvature. Scanning of the preparation and crown design were performed using the Cerec 3D Scan system. Ceramic crowns were milled using the Sirona MC milling unit and Vita Mark II blocks. Blocks were cemented to the reference plastic teeth using epoxy glue on the pulpal floor only and finger pressure for 1 min. Upon completion of the cementation step, misfit between the restoration and abutment were measured by microphotography and the silicone replica technique using light body silicon material on Mesial (M), Distal (D), Buccal (B) and Lingual (L) surfaces. Results: Mean and SDs of marginal gaps in micrometers were: G1/M: 68.49 (1.20), G1/D: 75.37 (3.70), G1/B: 90.92 (1.58), G1/L: 99.14 (0.83), G2/M: 58.88 (1.12), G2/D: 57.09 (0.97), G2/B: 66.67 (0.89), G2/L: 69.78 (1.28). ANOVA indicated significant differences among occlusal curvature (P<0.05); surface area (P<0.05) and the interaction (P<0.05). The Tukey test revealed that the G1 had greater margin gaps than G2 with a statistical difference (P<0.05). The values for B and L were significantly higher than M and D (P>0.05). Conclusions: The difference in occlusal curvature design on a CAD/CAM crown preparation significantly affected the marginal fit. The marginal fit was also significantly affected by the location of the margin and, Mesial and Distal locations exhibited smaller margin gaps values when compared with Lingual and Buccal areas.
Division: IADR/AADR/CADR General Session
Meeting:2015 IADR/AADR/CADR General Session (Boston, Massachusetts) Location: Boston, Massachusetts
Year: 2015 Final Presentation ID:3538 Abstract Category|Abstract Category(s):Dental Materials 3: Ceramic-based Materials and Cements
Authors
Piolli De Oliveira Prado, Marina
( Federal University of Jequitinhonha and Mucuri Valleys
, Diamantina
, MG
, Brazil
)
Ferreira, Lais
( Araraquara School of Dentistry
, Araraquara
, SP
, Brazil
)
Simino De Melo, Lucas
( University of Brasília
, Brasília
, DF
, Brazil
)
Akkus, Anna
( Case Western Reserve University
, Cleveland
, Ohio
, United States
)
Akkus, Ozzan
( Case Western Reserve University
, Cleveland
, Ohio
, United States
)
Roperto, Renato
( Case Western Reserve University
, Cleveland
, Ohio
, United States
)