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http://dx.doi.org/10.4047/jkap.2011.49.1.22

Clinical convergence angle and rounding radius on tooth preparation for zirconia all-ceramic crown  

Kim, Hye-Eun (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University)
Woo, Yi-Hyung (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University)
Pae, Ah-Ran (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University)
Kim, Hyeong-Seob (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University)
Publication Information
The Journal of Korean Academy of Prosthodontics / v.49, no.1, 2011 , pp. 22-28 More about this Journal
Abstract
Purpose: This article attempted to examine how teeth for restoration is made in a clinical practice and utilize it as future educational material of teeth formation and basic data for additional research. Materials and methods: This experiment investigated the models sent to milling center for production of zirconia crowns. After scanned with Lava CAD/CAM System (3M ESPE, Seefeld, Germany), they are measured on 'ImageJ (version 1.32j, National Institutes of Health, USA)' program and compared and analyzed. Convergence angle from mesio-distal surfaces and bucco-lingual surfaces of each teeth are measured. Also, bucco-lingual diameter of the region lowered as much as 0.4 mm from incisal edge in anterior teeth except canines.(This measure is defined as the Peak 0.4) The analysis of data between each group was conducted by Windows SPSS statistic program, and was proved significant on 95% confidence level by independent t-test, one-way ANOVA and multiple analysis (Sheff${\ test). Results: The mean value of convergence angle was $18.67^{\circ}$ It is ranked as molar ($26.70^{\circ}$) > premolar ($16.87^{\circ}$) > anterior teeth ($14.81^{\circ}$) in the order of mesio-distal convergence angle; anterior teeth ($22.32^{\circ}$) > molar ($20.93^{\circ}$) > premolar ($15.41^{\circ}$) in the order of bucco-lingual convergence angle. The mean value of Peak 0.4 was 1.18 mm. Conclusion: Convergence angle of abutment of zirconia all ceramic crown has difference depending on the location in the arch. Due to the nature of production of zirconia all ceramic crown, convergence angle of abutment and line angle finishing degree can have an effect on internal suitability of restoration.
Keywords
Zirconia; Tooth preparation; Convergence angle; Rounding radius;
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Times Cited By KSCI : 1  (Citation Analysis)
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1 Annerstedt A, Engstro¨m U, Hansson A, Jansson T, Karlsson S, Liljhagen H, Lindquist E, Rydhammar E, Tyreman-Bandhede M, Svensson P, Wandel U. Axial wall convergence of full veneer crown preparations. Documented for dental students and general practitioners. Acta Odontol Scand 1996;54:109-12.   DOI   ScienceOn
2 Seghi RR, Sorensen JA. Relative flexural strength of six new ceramic materials. Int J Prosthodont 1995;8:239-46.
3 Rekow ED. High-technology innovations-and limitations--for restorative dentistry. Dent Clin North Am 1993;37:513-24.
4 Oilo G, To¨rnquist A, Durling D, Andersson M. All-ceramic crowns and preparation characteristics: a mathematic approach. Int J Prosthodont 2003;16:301-6.
5 Prothero JH. Prosthetic dentistry. Medico-Dental Publishing Co.; 1916. pp. 1128.
6 Leempoel PJ, Lemmens PL, Snoek PA, van't Hof MA. The convergence angle of tooth preparations for complete crowns. J Prosthet Dent 1987;58:414-6.   DOI   ScienceOn
7 Kong SH, Woo YH. Accidental damage to teeth adjacent to prepared tooth. Masters thesis, Dept. of Dentistry, Graduate School, Kyung-Hee University, Seoul, Korea, 2004.
8 Kim SJ, Pae AR, Woo YH, Kim HS. Clinical convergence angle of prepared tooth for full veneer crowns. J Dent Rehab Appl Sci 2010;26;21-32.
9 Iwai T, Komine F, Kobayashi K, Saito A, Matsumura H. Influence of convergence angle and cement space on adaptation of zirconium dioxide ceramic copings. Acta Odontol Scand 2008;66:214-8.   DOI   ScienceOn
10 Ohm E, Silness J. The convergence angle in teeth prepared for artificial crowns. J Oral Rehabil 1978;5:371-5.   DOI
11 Goodacre CJ, Campagni WV, Aquilino SA. Tooth preparations for complete crowns: an art form based on scientific principles. J Prosthet Dent 2001;85:363-76.   DOI   ScienceOn
12 Kent WA, Shillingburg HT Jr, Duncanson MG Jr. Taper of clinical preparations for cast restorations. Quintessence Int 1988; 19:339-45.
13 Nordlander J, Weir D, Stoffer W, Ochi S. The taper of clinical preparations for fixed prosthodontics. J Prosthet Dent 1988;60:148-51.   DOI   ScienceOn
14 3M ESPE. $Lava^{TM}$ Handling and preparation guidelines for dentists and labs. 2009.
15 Smith CT, Gary JJ, Conkin JE, Franks HL. Effective taper criterion for the full veneer crown preparation in preclinical prosthodontics. J Prosthodont 1999;8:196-200.   DOI   ScienceOn
16 Shillingburg HT Jr, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of Fixed Prosthodontics. 3rd ed. Quintessence Publishing; IL; 1997. pp. 120-52.
17 Beuer F, Edelhoff D, Gernet W, Naumann M. Effect of preparation angles on the precision of zirconia crown copings fabricated by CAD/CAM system. Dent Mater J 2008;27:814-20.   DOI   ScienceOn
18 Mack PJ. A theoretical and clinical investigation into the taper achieved on crown and inlay preparations. J Oral Rehabil 1980;7:255-65.   DOI
19 Kaufman EG, Coelho AB, Colin L. Factors influencing the retention of cemented gold castings. J Prosthet Dent 1961;11:486-502.