Aim: Transferring an accurate copy of the patient's soft and hard tissue to the dental laboratory is of essential importance. Various methods of implant impression have different outcomes on dimensions of final cast. This study aimed to compare two methods of implant impression on abutment level with and without impression coping on two parallel implants.
Materials and methods: In this experimental study, a resin model with two holes for fixing the implant was made. The first and second implants had a 4 and 11 mm distance to canine respectively. In this study two methods were used for impression: first was direct (without impression coping) and second was indirect (with the impression coping). Ten impressions were prepared for a total of 10 stone casts. For analyzing the abutment analogs positions, each cast was analyzed using a cruicial malformation and malarticulatoin (CMM) in three dimensions (X, Y, and Z). The difference in dimensions of final casts and laboratory models were analyzed using Independent t-test.
Results: The results did not show a significant difference between direct and indirect methods in Z and Y axis in absolute transmission (Är). The dimensional changes in the X-axis in the direct method was 0.647 ± 0.155 which is 0.067 ± 0.146 more than the indirect method. A significant difference (p = 0.044) was observed between the two methods in X-axis.
Conclusion: Based on the results, this research found the indirect impression on abutment surface to be more accurate than the direct one. In general, two methods were not significantly different, and dentists can use the simple method of the direct impression for making implant prosthetics.
Clinical significance: Reconstruction of implant's accurate position in the process of impression, along with a tension-free insertion, is the first step in having an accurate prosthesis. Abutment level impression with the impression coping is slightly more accurate than the one without impression coping.
Misch, CE. Dental implant prosthetics. 2nd ed. St Louis: Elsevier Mosby; 2015. 933 p.
Assif D, Marshak B, Schmidt A. Accuracy of implant impression techniques. Int J Oral Maxillofac Implants. 1996;11(2): 216-222.
Jemt T. In vivo measurements of precision of fit involving implant-supported prostheses in the edentulous jaw. Int J Oral Maxillofac Implants. 1996;11(2):151-158.
Conrad HJ, Pesun IJ, De Long R, Hodges JS. Accuracy of two impression techniques with angulated implants. J Prosthet Dent. 2007;97(6):349-356.
Pesun IJ. Intrusion of teeth in the combination implant-tonatural- tooth fixed partial denture: a review of the theories. J Prosthodont. 1997;6(4):268-277.
Wee AG, Aquilino SA, Schneider RL. Strategies to achieve fit in implant prosthodontics: a review of the literature. Int J Prosthodont. 1999;12(2):167-178.
Lee H, Ercoli C, Funkenbusch PD, Feng C. Effect of subgingival depth of implant placement on the dimensional accuracy of the implant impression: an in vitro study. J Prosthet Dent. 2008;99(2):107-113.
Tan KB, Rubenstein JE, Nicholls JI, Yuodelis RA. Threedimensional analysis of the casting accuracy of one-piece, osseointegrated implant-retained prostheses. Int J Prosthodont. 1993;6(4):346-363.
Heckmann SM, Karl M, Wichmann MG, Winter W, Graef F, Taylor TD. Cement fixation and screw retention: parameters of passive fit. An in vitro study of three-unit implantsupported fixed partial dentures. Clin Oral Implants Res. 2004;15(4):466-473.
Aparicio C. A new method to routinely achieve passive fit of ceramometal prostheses over Branemark osseointegrated implants: a two-year report. Int J Periodontics Restorative Dent. 1994;14(5):404-419.
Spector MR, Donovan TE, Nicholls JI. An evaluation of impression techniques for osseointegrated implants. J Prosthet Dent. 1990;63(4):444-447.
O.zkan Y OzM, Akalin F, Kulak-O.zkan Y, Valandro LF, Faria R. Evaluation of the methods used for impression making for different implant systems in prosthetic dentistry. Cienc Odontol Bras. 2006;9(2):11.
Alikhasi M, Siadat H, Monzavi A, Momen-Heravi F. Threedimensional accuracy of implant and abutment level impression techniques: effect on marginal discrepancy. J Oral Implantol. 2011;37(6):649-657.
Hatim NA AMB. Dimensional accuracy of impression techniques for the endosteal implants (An in vitro study): Part I. Al. Rafidain Dent J. 2007;7(1):20-31.
Prithviraj DR, Pujari ML, Garg P, Shruthi DP. Accuracy of the implant impression obtained from different impression materials and techniques: review. 2011;3(2):106-111.
Sorrentino R, Gherlone EF, Calesini G, Zarone F. Effect of implant angulation, connection length, and impression material on the dimensional accuracy of implant impressions: an in vitro comparative study. Clin Implant Dent Relat Res. 2010;12 Suppl 1:e63-76.
Mojon P, Oberholzer JP, Meyer JM, Belser UC. Polymerization shrinkage of index and pattern acrylic resins. J Prosthet Dent. 1990;64(6):684-688.
Jahandideh Y, Pournasiri E. A Comparison between the New Method of Impression and Connected (Contiguous) Open- Tray Method in Implants. Biotech Res Asia. 2016;13(3):1-7.