Practice‐based clinical evaluation of metal–ceramic and zirconia molar crowns: 3‐year results

Abstract

This practice-based study evaluates the clinical performance of conventionally luted metal-ceramic and zirconia molar crowns fabricated with pronounced anatomical core design and a prolonged cooling period of the veneering porcelain. Fifty-three patients were treated from 07/2008 until 07/2009 with either metal-ceramic crowns (MCC) (high-noble alloy + low-fusing porcelain) or zirconia crowns (Cercon System, DeguDent, Germany). Forty-nine patients (30 women/19 men) with 100 restorations (metal-ceramic: 48/zirconia: 52, mean observational period: 36·5 ± 6 months) participated in a clinical follow-up examination and were included in the study. Time-dependent survival (in situ criteria), success (event-free restorations) and chipping rates (defects of the veneering ceramics) were calculated according to the Kaplan-Meier method and analysed in relation to the crown fabrication technique, using a Cox regression model (P < 0·05). Three complete failures (metal-ceramic: 1, zirconia: 2) were recorded (survival rate after 3 years: metal-ceramic: 97·6%, zirconia: 95·2%). Of the metal-ceramic restorations, 90·9% remained event-free (two ceramic fractures, one endodontic treatment), whereas the success rate for the zirconia was 86·8% (two ceramic fractures, one endodontic treatment, one secondary caries). No significant differences in survival (P = 0·53), success (P = 0·49) and ceramic fracture rates (P = 0·57) were detected. The combination of a pronounced anatomical core design and a modified firing of the veneering porcelain for the fabrication of zirconia molar crowns resulted in a 3-year survival, success and chipping rate comparable to MCC.

Effect of silane and phosphate primers on the adhesive performance of atri-n-butylborane initiated luting agent bonded to zirconia

“…Zirconia has better mechanical properties than all of the previously introduced ceramics 3) . Furthermore, much clinical research into zirconia-based all-ceramic restorations has confirmed that zirconia ceramics exhibit high stability as a frame work material for full coverage crowns [4][5][6][7] , fixed partial dentures (FPDs) 5,[8][9][10][11] , and implant abutments [12][13][14] . It has often been reported that full-coverage zirconia ceramic restoration and FPDs might not require adhesive cementation and that they can be cemented with conventional cements, including zinc phosphate 4,6,8,11) or glass ionomer cement 5,10) .…”

Influence of crown design and material on chipping-resistance of all-ceramic molar crowns: An in vitro study

“…19,27 Two reasons that could explain this incidence are core thickness and design. In the present study, the metal and zirconia coping were designed with even thickness.…”

“…This result is in agreement with findings reported in several clinical studies that compared the longevity of zirconiabased and PFM crowns. 8,27 The similarity of the mechanical properties and composition of the 2 veneering materials, IPS e.max Ceram and ZirPress, could explain their comparable chipping behavior. In contrast, the void-free and stronger veneering material (LDGC) resisted chipping in CAD-on crowns for the entire length of the mechanical fatigue test.…”

Reconstruction of esthetically compromised maxillary anterior teeth with CAD CAM zirconia crowns – A case report

“…Regarding the available literature and some short-term clinical trials, core fractures were noticeably rare reported in zirconia-based single crowns over 1 to 3 years of follow up, while the veneer fracture proportion ranged from 0% to 15% [10,11]. The incidence of chipping on zirconia based fixed restoration has been reported ranging from 0% to 4% in clinical studies with 20 to 60 months follow-up [12][13][14]. Other limitations are special Milling center is required for the scanning and processing, this phase of production is, to some degree, tedious.…”