Measurement of the accuracy of dental working casts using a coordinate measuring machine
Abstract
Background/Aim. Dental impressions present a negative imprint of intraoral tissues of a patient which is, by pouring in gypsum, transferred extraorally on the working cast. Casting an accurate and precise working cast presents the first and very important step, since each of the following stages contributes to the overall error of the production process, which can lead to inadequately fitting dental restorations. The aim of this study was to promote and test a new model and technique for in vitro evaluation of the dental impression accuracy, as well as to asses the dimensional stability of impression material depending on the material bulk, and its effect on the accuracy of working casts. Methods. Impressions were made by the monophasic technique using the experimental master model. Custom trays with spacing of 1, 2 and 3 mm were constructed by rapid prototyping. The overall of 10 impressions were made with each custom tray. Working casts were made with gypsum type IV. Measurement of working casts was done 24 h later using a coordinate measuring machine. Results. The obtained results show that the working casts of all the three custom trays were in most cases significantly different in the transversal and sagittal planes in relation to the master model. The height of abutments was mainly unaffected. The degree of convergence showed certain significance in all the three custom trays, most pronounced in the tray with 3 mm spacing. Conclusion. The impression material bulk of 1–3 mm could provide accurate working casts when using the monophasic impression technique. The increase of the distance between abutment teeth influences the accuracy of working casts depending on the material bulk.
References
Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed pros-thodontics. St. Louis: Mosby Inc; 2006.
Quaas S, Rudolph H, Luthardt RG. Direct mechanical data ac-quisition of dental impressions for the manufacturing of CAD/CAM restorations. J Dent 2007; 35(12): 903−8.
Ender A, Mehl A. Accuracy of complete-arch dental impres-sions: a new method of measuring trueness and precision. J Prosthet Dent 2013; 109(2): 121−8.
Trifkovic B, Budak I, Todorovic A, Hodolic J, Puskar T, Jevremovic D, et al. Application of Replica Technique and SEM in Accuracy Measurement of Ceramic Crowns. Measur Sci Rev 2012; 12(3): 90−7.
Persson ASK, Odén A, Andersson M, Sandborgh-Englund G. Digiti-zation of simulated clinical dental impressions: virtual three-dimensional analysis of exactness. Dent Mater 2009; 25(7): 929−36.
Rodriguez JM, Bartlett DW. The dimensional stability of impres-sion materials and its effect on in vitro tooth wear studies. Dent Mater 2011; 27(3): 253−8.
Ceyhan JA, Johnson GH, Lepe X. The effect of tray selection, viscosity of impression material, and sequence of pour on the accuracy of dies made from dual-arch impressions. J Prosthet Dent 2003; 90(2): 143−9.
Caputi S, Varvara G. Dimensional accuracy of resultant casts made by a monophase, one-step and two-step, and a novel two-step putty/light-body impression technique: An in vitro study. J Prosthet Dent 2008; 99(4): 274−81.
Luthardt RG, Kühmstedt P, Walter MH. A new method for the computer-aided evaluation of three-dimensional changes in gypsum materials. Dent Mater 2003; 19(1): 19−24.
Brosky ME, Pesun IJ, Lowder PD, Delong R, Hodges JS. Laser digi-tization of casts to determine the effect of tray selection and cast formation technique on accuracy. J Prosthet Dent 2002; 87(2): 204−9.
Mishra S, Chowdhary R. Linear dimensional accuracy of a poly-vinyl siloxane of varying viscosities using different impression techniques. J Investig Clin Dent 2010; 1(1): 37−46.
Marković D, Puškar T, Hadžistević M, Potran M, Blažić L, Hodolič J. The dimensional stability of elastomeric dental impression materials. Contemp Mater 2012; 3(1): 105−10.
Poniatowska M. Parameters for CMM Contact Measurements of Free-Form Surfaces. Metrol Measur Sys 2011; 18(2): 199−208.
Nissan J, Gross M, Shifman A, Assif D. Effect of wash bulk on the accuracy of polyvinyl siloxane putty-wash impressions. J Oral Rehabil 2002; 29(4): 357−61.
Kumar V, Aeran H. Evaluation of Effect of Tray Space on the Accuracy of Condensation Silicone, Addition Silicone and Po-lyether Impression Materials: An In Vitro Study. J Indian Prosthodont Soc 2012; 12(3): 154−60.
Hoyos A. Influence of tray rigidity and material thickness on accuracy of polyvinyl siloxane impressions [thesis]. Gainesville, FL: Graduate School of the University of Florida; 2006.
de Araujo PA, Jorgensen KD. Effect of material bulk and under-cuts on the accuracy of impression materials. J Prosthet Dent 1985; 54(6): 791−4.
Rajapur A, Dixit S, Hoshing C, Raikar SP. The influence of tray space and repeat pours on the accuracy of monophasic polyvinylsiloxane impression. J Contemp Dent Pract 2012; 13(6): 824−9.
Mandikos MN. Polyvinyl siloxane impression materials: an up-date on clinical use. Aust Dent J 1998; 43(6): 428−34.
Fehling AW, Hesby RA, Pelleu GB. Dimensional stability of au-topolymerizing acrylic resin impression trays. J Prosthet Dent 1986; 55(5): 592−7.
Sched RC, Weiss G. Woelfel's dental anatomy. Philadelphia: Lippincott Williams&Wilkins; 2012. p. 41.
International Organization for Standardization. ISO/TS 17450-1. Geometrical product specification (GPS) – General concept – Part 1: Model for geometric specification and verifi-cation. Geneva: International Organization for Standardiza-tion; 2002.
Weckenmann A, Knauer M, Kunzmann H. The Influence of Mea-surement Strategy on the Uncertainty of CMM-Measurements. CIRP Annal Manufac Technol 1998; 47(1): 451−4.
Wilhelm RG, Hocken R, Schwenke H. Task Specific Uncertainty in Coordinate Measurement. CIRP Annal Manufac Technol 2001; 50(2): 553−63.
Chandran DT, Jagger DC, Jagger RG, Barbour ME. Two- and three-dimensional accuracy of dental impression materials: ef-fects of storage time and moisture contamination. Biomed Mater Eng 2010; 20(5): 243−9.
de Long R, Heinzen M, Hodges JS, Ko CC, Douglas WH. Accuracy of a system for creating 3D computer models of dental arches. J Dent Res 2003; 82(6): 438−42.
Boulton JL, Gage JP, Vincent PF, Basford KE. A laboratory study of dimensional changes for three elastomeric impression materials using custom and stock trays. Aust Dent J 1996; 41(6): 398−404.
Johnson GH, Craig RG. Accuracy of four types of rubber im-pression materials compared with time of pour and a repeat pour of models. J Prosthet Dent 1985; 53(4): 484−90.
Lewinstein I. The ratio between vertical and horizontal changes of impressions. J Oral Rehabil 1993; 20(1): 107−14.
Jevremovic DP, Puskar TM, Budak I, Vukelic DJ, Kojic V, Eggbeer D, et al. An RE/RM approach to the design and manufacture of removable partial dentures with a biocompatibility analysis of the f75 Co-Cr-Slm alloy. Mat Technol 2012; 46(2): 123−9.
Wu M, Tinschert J, Augthun M, Wagner I, Schädlich-Stubenrauch J, Sahm PR, et al. Application of laser measuring, numerical simu-lation and rapid prototyping to titanium dental castings. Dent Mat 2001;7(2):02−8.
Chan DC, Chan BH, Chung AK. Mathematical modeling of mo-lar tooth preparations for complete crowns. J Dent 2007; 35(11): 875−7.
Schaefer O, Schmidt M, Goebel R, Kuepper H. Qualitative and quantitative three-dimensional accuracy of a single tooth cap-tured by elastomeric impression materials: An in vitro study. J Prosthet Dent 2012; 108(3): 165−72.
Tjan AH, Nemetz H, Nguyen LTP, Contino R. Effect of tray space on the accuracy of monophasic polyvinylsiloxane im-pressions. J Prosthet Dent 1992;8(1): 19−28.
Eames WB, Sieweke JC, Wallace SW, Rogers LB. Elastomeric im-pression materials: effect of bulk on accuracy. J Prosthet Dent 1979; 41(3): 304−7.