In vitro evaluation of the marginal and internal discrepancies of different esthetic restorations.
OBJECTIVE
This study examined the fit of two types of all-ceramic single crowns and indirect composite resin full coverage crowns.


METHODS
Thirty intact human mandibular first premolars were selected for this study and prepared using a machine to standardize the dimensions and randomly divided into 3 groups. Slip cast (IC) (In-Ceram Zirconia, Vita Zahnfabrik), copy-milled zirconia (CM) (ICE, Zirkonzahn) and indirect composite resin crowns (NECO, HeraeusKulzer, Hanau, Germany), (N=30, 10 per group) were fabricated according to each manufacturer's recommendations. Before cementation, discrepancies were measured at the marginal zone in each crown. Crowns were then cemented with G-Cem capsule self-adhesive luting cement (GC Corporation, Tokyo, Japan). Four positions were marked for each zone (mid-facial, mid-mesial, mid-distal, and mid-lingual) and three measurements were made at each of the four positions yielding to a total of 12 measurements per crown before and after cementation. The measurements were performed at a different magnification using a stereo microscope (SZ11, Olympus, Japan). Marginal, axial and occlusal zone discrepancies (µm) were evaluated after cementation. The data were statistically analyzed using two-way ANOVA and Tukey's test.


RESULTS
Before cementation, significantly less marginal discrepancies were noted compared with after cementation in all groups (p<0.05). No significant differences were found within each zone (Marginal= IC: 84.2, NECO: 95.22, CM: 84.22; Axial= IC: 54.22, NECO: 64.2, CM: 55.22; Occlusal= IC: 119.97, NECO: 129.18, CM: 121.15) in the three crown systems (p>0.05). Occlusal zone discrepancies were significantly higher than those of the marginal and axial zones in all groups (p<0.05).


CONCLUSIONS
Slip cast and copy-milled zirconia crowns showed comparable fit to composite resin crowns in all marginal, axial and occlusal areas.
Amal Abdelsamad
AA
Sakrana
D000704:Analysis of Variance; D002484:Cementation / Q000379:methods; D002516:Ceramics; D003188:Composite Resins; D003442:Crowns; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D004955:Esthetics, Dental; D006801:Humans; D008422:Materials Testing; D011897:Random Allocation; D012016:Reference Values; D019279:Resin Cements; D013997:Time Factors
D003188:Composite Resins; D019279:Resin Cements