Accuracy of Definitive Casts Using 4 Implant-Level Impression Techniques in a Scenario of Multi-Implant System With Different Implant Angulations and Subgingival Alignment Levels

Abstract

PURPOSE: To evaluate the effect of various implant-level impression techniques on the accuracy of definitive casts for a multiple internal connection implant system with different implant angulations and subgingival depths. MATERIAL AND METHODS: Six tapered Screw-Vent implants were placed in a reference model with different angles (0, 15, and 30 degrees) and subgingival positions (0, 1, and 3 mm). Twenty medium-consistency polyether impressions of this model were made with 4 techniques (n = 5 per group): (1) indirect technique, (2) unsplinted direct technique, (3) acrylic resin-splinted direct technique, and (4) metal-splinted direct technique. Impressions were poured with type IV dental stone. The interimplant distances were measured for casts using a coordinate measuring machine and the deviations compared with the reference model were calculated. Data were analyzed using intraclass correlation coefficient, ANOVA and Bonferroni test ( = 0.05). RESULTS: Four impression procedures showed significant differences (P = 0.0001). Only group 4 casts showed no significant differences in comparison with the reference model (P = 0.666) (ANOVA repeated measures). CONCLUSIONS: The impression procedure affected the accuracy of definitive casts. The metal-splinted direct technique produced the most accurate casts, followed by acrylic resin-splinted direct, indirect, and unsplinted direct techniques. ABSTRACT (199 words)Purpose To evaluate the effect of four implant-level impression techniques on the accuracy of

Accuracy of 3 different impression techniques for internal connection angulated implants

“…These findings are in agreement with several studies which reported the superiority of the splinted technique for internal connection implants. [11][12][13][14][15][16][17] Moreover, regarding implant angulation, 3 in vitro investigations showed that the splinted technique was more accurate than the nonsplinted technique for making an impression of angulated implants. 5,7,16 Some authors, however, have found no significant differences in the accuracy of internal connection implant impressions with the splinted and nonsplinted techniques.…”

“…[11][12][13][14][15][16][17] Moreover, regarding implant angulation, 3 in vitro investigations showed that the splinted technique was more accurate than the nonsplinted technique for making an impression of angulated implants. 5,7,16 Some authors, however, have found no significant differences in the accuracy of internal connection implant impressions with the splinted and nonsplinted techniques. [18][19][20][21] The conflicting findings in the literature concerning the most accurate impression technique might be explained by the different study designs and implant systems used, the different impression and splinting materials, the inaccurate repositioning of the impression copings, the various angulations of the implants, and the variable dental stone expansion.…”

“…8,10 Moreover, most clinicians have suggested that the direct technique with splinting of impression copings in internal connection implants provides greater accuracy than that of the nonsplinted technique. [12][13][14][15][16][17] In contrast to those findings, other studies have reported no significant differences in internal connection implant impression accuracy resulting from splinted versus nonsplinted techniques. [18][19][20][21] Although different materials have been proposed for impression coping splinting, including impression plaster, polyether, and light-polymerizing composite resin, autopolymerizing acrylic resin splinting with or without dental floss is used more often to prevent coping movements during the impression-making procedure.…”

The Effect of Implant Angulation on the Transfer Accuracy of External‐Connection Implants

“…Both of these impression techniques are generally used for transferring implant position to the final cast in dental practice . Comparing the square and conical transfer impression copings in different implant systems has been addressed in the literature . Some studies showed that the indirect impression technique (transfer) created a more accurate working cast compared with the direct techniques (pick‐up) .…”

Analysing the precision of dental impression on angulated implants using full arch and sectional approaches in the abutment and fixture levels

“…Interestingly, in this experiment, the exact position of the implants were not attained in any of the impression methods. (15) This shows that the exact fit of the superstructure might be unattainable. Since the exact acceptable amount of misfit frame and rack on several implants are not determined, it is possible to define the discrepancy amount of less than 30 µ , which is not detectible clinically, as the reference to accept or reject the fit frame and rack.…”