Statement of problem
Gold electroformed metal-ceramic restorations have been promoted as alternatives to
conventional metal-ceramic restorations. However, little is known about the relationship
between tooth preparation design and marginal adaptation for this type of crown.
Purpose
This study evaluated the influence of 3 different finish line designs on the marginal
adaptation of electroformed metal copings and metal-ceramic crowns.
Material and methods
Three steel dies were prepared for maxillary central incisor crowns with 3 finish
line designs: shoulder, rounded shoulder, and deep chamfer preparations. Eight standardized
electroformed metal-ceramic crowns were fabricated for each group. Marginal discrepancies
were measured at 60 points for each specimen along the circumferential margin at 4
sites (labial, mesial, lingual, and distal surfaces, with 15 points for each site)
before and after firing procedures using a laser microscope. Data among the 3 different
groups were statistically analyzed using the Kruskal-Wallis test and the Mann-Whitney
U test with the Bonferroni correction. Marginal discrepancies between prefiring and
postfiring procedures were evaluated using the Wilcoxon signed-ranks test (α=.05).
Results
Significant differences in the marginal discrepancies of electroformed metal copings
without porcelain and metal-ceramic crowns were found among all groups. The lowest
range of median marginal discrepancy values (P<.05) at 4 sites, both before and after firing, occurred with the deep chamfer preparation
(17.64-21.78 μm and 23.96-25.72 μm, respectively). The highest range values were observed
in the shoulder preparation (38.13-49.89 μm and 73.87-89.44 μm, respectively). In
all situations, the marginal discrepancies of the postfiring procedures were significantly
greater (P=.02 or less) than those of the prefiring procedures.
Conclusion
Within the limitations of this study, the marginal adaptation of electroformed metal
copings or metal-ceramic crowns is affected by finish line design and sequentially
diminished by porcelain firing procedures.
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References
- Evolution of dental ceramics in the twentieth century.J Prosthet Dent. 2001; 85: 61-66
- Survival rate of mono-ceramic and ceramic-core CAD/CAM-generated anterior crowns over 2-5 years.Eur J Oral Sci. 2004; 112: 197-204
- Retrospective assessment of 546 all-ceramic anterior and posterior crowns in a general practice.J Prosthet Dent. 2001; 85: 544-550
- Long-term clinical results of galvano-ceramic and glass-ceramic individual crowns.J Prosthet Dent. 2000; 83: 530-534
- Electroforming a gold matrix for indirect inlays.J Prosthet Dent. 1961; 11: 959-966
- The dental application of electroformed pure gold. I. Porcelain jacket crown technique.Aust Dent J. 1979; 24: 163-170
- Electroforming in restorative dentistry: new dimensions in biologically based prostheses.Quintessence, Chicago2000 (p. 28-61)
- Gingival and alveolar bone reaction to marginal fit of subgingival crown margins.Scand J Dent Res. 1986; 94: 109-114
- A rationale for comparison of plaque-retaining properties of crown systems.J Prosthet Dent. 1989; 62: 264-269
- Effect of in vivo crown margin discrepancies on periodontal health.J Prosthet Dent. 1991; 65: 357-364
- The estimation of cement film thickness by an in vivo technique.Br Dent J. 1971; 131: 107-111
- The fit of metal-ceramic crowns, a clinical study.Dent Mater. 1985; 1: 197-199
- Preparation design and margin distortion in porcelain-fused-to-metal restorations.J Prosthet Dent. 1973; 29: 276-284
- Distortion related to margin design in porcelain-fused-to-metal restorations.J Prosthet Dent. 1980; 43: 149-155
- Evaluation of the marginal integrity of ceramometal restorations. Part I.J Prosthet Dent. 1981; 46: 59-65
- Marginal distortion of the porcelain-bonded-to-metal complete crown: an SEM study.J Prosthet Dent. 1982; 47: 146-153
- Fit of three porcelain-fused-to-metal marginal designs in vivo: a scanning electron microscope study.J Prosthet Dent. 1985; 53: 24-29
- Scanning electron microscopy of the marginal fit of ceramometal restorations with facially butted porcelain margins.J Prosthet Dent. 1987; 58: 13-19
- Effect of incompatibility stress on the fit of metal-ceramic crowns.J Dent Res. 1987; 66: 1341-1345
- Change in marginal fit as related to margin design, alloy type, and porcelain proximity in porcelain-fused-to-metal restorations.J Prosthet Dent. 1988; 60: 435-439
- Influence of finish-line geometry on the fit of crowns.Int J Prosthodont. 1993; 6: 25-30
- Marginal fit changes during porcelain firing cycles.J Prosthet Dent. 1995; 73: 49-54
- Marginal distortion of thermally incompatible metal ceramic crowns with overextended margins.Int J Prosthodont. 1998; 11: 325-332
- Metal ceramic crowns—a review of tooth preparation.Eur J Prosthodont Restor Dent. 1999; 7: 79-84
- Thermal cycling distortion of metal ceramics: part I—metal collar width.J Prosthet Dent. 1992; 67: 603-608
- Thermal cycling distortion of metal ceramics: part II—etiology.J Prosthet Dent. 1992; 68: 284-289
- Effects of firing cycle and surface finishing on distortion of metal ceramic castings.J Prosthet Dent. 1995; 74: 476-481
- Marginal fit of electroformed ceramometal crowns.J Prosthodont. 1996; 5: 111-114
- Comparison of marginal fit of 3 different metal-ceramic systems: an in vitro study.Int J Prosthodont. 2000; 13: 405-408
- Determination of the minimum number of marginal gap measurements required for practical in vitro testing.J Prosthet Dent. 2000; 83: 40-49
Article info
Publication history
Nihon University School of Dentistry, Tokyo, Japan
Footnotes
Supported by a grant from the Ministry of Education, Culture, Sports, Science, and Technology to promote multidisciplinary research projects (2001) and Special Research Grants for the Development of Distinctive Education from the Promotion and Mutual Aid Corporation for Private Schools of Japan (2004 and 2005).
Identification
Copyright
© 2006 The Editorial Council of The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
