In vitro evaluation of the marginal and internal discrepancies of different esthetic restorations

Abstract

ObjectiveThis study examined the fit of two types of all-ceramic single crowns and indirect composite resin full coverage crowns. Material and MethodsThirty 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. ResultsBefore 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). ConclusionsSlip cast and copy-milled zirconia crowns showed comparable fit to composite resin crowns in all marginal, axial and occlusal areas.

Marginal adaptation of fixed prosthodontics

“…There have been numerous studies of various all-ceramic crown systems with a wide range of marginal openings from 0 to 313 μm and a reported mean marginal opening of 155 μm. McLean and Von Fraunhofer [32] examined more than 1,000 crowns after a 5-year period and concluded that a marginal opening of ≤120 μm was clinically acceptable [5].…”

“…Some authors have pointed out the importance to evaluate the effect of the finish line on the marginal gap of allceramic crowns [4]. Other factors besides the finish line also affect the faithfulness of the marginal adaptation of prosthetic crowns, which is the addition of the covering ceramic crowns [5,6]. Anadioti reported that fullcoverage dental restorations are an integral part of fixed prosthodontics.…”

Assessment of the fit of zirconia-based prostheses fabricated with two different scan methods

“…This finding is also consistent with previous studies. 30 Sorensen reported that standardized methods for determination of crown margin include the direct view technique, the cross-sectioning technique, the impression replica technique, and other methods (e.g., the WT). 31 The RT was first introduced by Molin and Karlsson,32 who used this technique to compare the fitness between gold inlays and ceramic inlays.…”

In vitro Evaluation of the Accuracy of Seating Cast Metal Fixed Partial Denture on the Abutment Teeth with Varying Degree of Convergence Angle

“…The marginal fit of any restoration is vital for its long term success [12]. Geometry of the tooth preparation, including the type of finish line and the degree of taper is an important factor in obtaining close marginal adaptation [13].…”