J Korean Acad Prosthodont.  2019 Oct;57(4):321-327. 10.4047/jkap.2019.57.4.321.

Effect of additional firing process after sintering of monolithic zirconia crown on marginal and internal fitness

• Shin MS
• Lee H

• KMID: 2461137
• DOI: http://doi.org/10.4047/jkap.2019.57.4.321

Abstract

PURPOSE
To evaluate an effect of additional firing process after sintering of monolithic zirconia crown on marginal and internal fit through three-dimensional analysis.
MATERIALS AND METHODS
Ten monolithic zirconia crowns were fabricated using titanium abutment model. Monolithic zirconia crowns were designed, milled, and sintered as a control group, and additional firing with coloring was performed as a test group. Three dimensional analysis were performed by using triple-scan protocol, and cross-section analysis on mesio-distal and disto-lingual section was evaluated to measure marginal and internal fitness. Then, three-dimensional surface difference on between two groups was evaluated (α=.05).
RESULTS
There was statistically significant difference between the control group (32.0 ± 24.3 µm) and the test group (17.0 ± 10.8 µm) in the mesial axial wall (P < .02) and the control group (60.2 ± 24.3 µm) and the test group (71.8 ± 21.5 µm) in the distal axial wall (P < .01). There was no statistically significant difference at the remaining point.
CONCLUSION
There was no statistical significance on the deviation of inner surface of crown according to firing number, and the results of both group were considered clinically acceptable.

Keyword

Triple-scan protocol; 3D analysis; Monolithic zirconia crown; Marginal fitness; Internal fitness

MeSH Terms

Crowns*
Fires*
Titanium
Titanium

Figure

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  Fig. 1 Master model with titanium block made by using CAD/CAM.

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  Fig. 2 The constant seating force.

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  Fig. 3 Scanned three-dimensional surface data. (A) Titanium master die, (B) Monolithic zirconia crown, (C) Superimposed crown on the master die.

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  Fig. 4 Measurement points for marginal gap (1, 6, a, g) and internal gap (2, 3, 4, 5, b, c, d, e, f). (A) Mesio-distal section, (B) Bucco-lingual section.

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  Fig. 5 Mean of marginal and internal gap of monolithic zirconia crown: Mesio-distal section (*Significant at P < .05).

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  Fig. 6 Mean of marginal and internal gap of monolithic zirconia crown: Bucco-lingual section.

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  Fig. 7 Three-dimensional inner surface comparison of monolithic zirconia crown.

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  Fig. 8 Monolithic zirconia crown superimposed on the master die. (A, B) control group, (C, D) test group.

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