Marginal and internal fit of CAD-CAM-fabricated composite resin and ceramic crowns scanned by 2 intraoral cameras.
BACKGROUND
The precision of fit of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) complete crowns is affected by digital impression and restorative material.


OBJECTIVE
The purpose of this in vitro study was to evaluate by microcomputed tomography (μCT) the marginal and internal adaptation of composite resin and ceramic complete crowns fabricated with 2 different intraoral cameras and 2 restorative materials.


METHODS
Ten extracted human third molars received crown preparations. For each prepared molar, 2 digital impressions were made with different intraoral cameras of the CEREC system, Bluecam and Omnicam. Four groups were formed: LB (Lava Ultimate+Bluecam), EB (Emax+Bluecam), LO (Lava Ultimate+Omnicam), and EO (Emax+Omnicam). Before measuring the precision of fit, all crowns were stabilized with a silicone material. Each unit (crown + prepared tooth) was imaged with μCT, and marginal and internal discrepancies were analyzed. For the 2D analysis, 120 measurements were made of each crown for marginal adaptation, 20 for marginal discrepancy (MD), and 20 for absolute marginal discrepancy (AMD); and for internal adaptation, 40 for axial space (AS) and 40 for occlusal space (OS). After reconstructing the 3D images, the average internal space (AIS) was calculated by dividing the total volume of the internal space by the contact surface. Data were analyzed with 2-way ANOVA and quantile regression.


RESULTS
Regarding marginal adaptation, no significant differences were observed among groups. For internal adaptation measured in the 2D evaluation, a significant difference was observed between LO and EO for the AS variable (Mann-Whitney test; P<.008). In assessment of AIS by the 3D reconstruction, LB presented significantly lower values than the other groups (Tukey post hoc test; P<.05). Bluecam presented lower values of AIS than Omnicam, and composite resin crowns showed less discrepancy than did ceramic crowns.


CONCLUSIONS
The marginal adaptations assessed in all groups showed values within the clinically accepted range. Moreover, the composite resin blocks associated with the Bluecam intraoral camera demonstrated the best results for AIS compared with those of the other groups.
Graduate student, School of Health Sciences, University of Brasília, Brasília, Brazil.
Alessandra C
AC
de Paula Silveira
Associate Professor, Department of Genetics and Morphology, Institute of Biology, University of Brasília, Brasília, Brazil.
Sacha B
SB
Chaves
Associate Professor, Department of Dentistry, School of Health Sciences, University of Brasília, Brasília, Brazil.
Leandro A
LA
Hilgert
Associate Professor, Department of Dentistry, School of Health Sciences, University of Brasília, Brasília, Brazil. Electronic address: apauladr@yahoo.com.br.
Ana Paula D
AP
Ribeiro
D002516:Ceramics; D003188:Composite Resins; D017076:Computer-Aided Design; D003442:Crowns; D003761:Dental Impression Technique / Q000295:instrumentation; D018772:Dental Marginal Adaptation; D003764:Dental Materials; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008964:Molar, Third; D012828:Silicones; D013499:Surface Properties; D055114:X-Ray Microtomography / Q000379:methods
D003188:Composite Resins; D003764:Dental Materials; C508050:IPS e.max Press; D012828:Silicones; D003776:Dental Porcelain; C074543:Cerec