Evaluation of Castable and Premachined Metal Base Abutment/Implant Interfaces Before and After Cyclical Load

Evaluation of the influence of connection configuration on the implant-abutment interface vertical misfit of original milled titanium and laser-sintered cobalt-chromium abutments

OBJECTIVES

This study aimed to assess the vertical misfit at the implant-abutment interface in external and internal connections across various implant brands, comparing original milled titanium abutments with laser-sintered cobalt-chromium (Co-Cr) abutments.

MATERIALS AND METHODS

A total of 160 implants from four different brands were utilized, with 80 featuring external connections (EC) and 80 internal connections (IC). Original milled titanium abutments (n = 160) and Co-Cr laser-sintered abutments (n = 160) were randomly attached to each connection type, following the manufacturer's recommended torque. After undergoing thermal cycling, the vertical misfit was measured using a scanning electron microscope. Statistical analyses were performed using the Kruskal-Wallis and Mann-Whitney U tests. The significance level was set at α = 0.05.

RESULTS

The original milled titanium abutments exhibited the lowest misfit values. Significant differences were identified between both abutment types for EC (d = 109.578 μm; p = 0.0001) and IC (d = 44.317 μm; p = 0.002). The EC with laser-sintered abutments demonstrated the highest marginal misfit values, with an average of nearly 30 μm, while a misfit value of 11.382 μm was achieved in the IC. Differences were observed among the brands for milled abutments in both EC and IC. Similarly, variations were also noted for the laser-sintered Co-Cr abutments in EC and IC configurations.

CONCLUSIONS

The vertical misfit of the original milled titanium abutments in all groups was within the clinically acceptable range for IC. The connection type significantly impacted the vertical misfit in laser-sintered Co-Cr abutments. Differences among the implant systems were observed for both connection types and abutment types evaluated.

CLINICAL RELEVANCE

Using original milled titanium abutments, particularly in internal connection systems, can lead to better fit and stability at the implant-abutment interface, potentially reducing the risk of mechanical complications and improving long-term implant success.

Influence of Implant Connection, Abutment Design and Screw Insertion Torque on Implant-Abutment Misfit

Background: An accurate fit at the implant-abutment interface is an important factor to avoid biological and mechanical complications. The aim of this study was to evaluate the marginal misfit at the implant-abutment interface on external and Morse taper connection, with straight and angulated abutments under different insertion torque loads. Materials and Methods: A total of 120 implants were used, 60 with external connection (EC) and 60 with Morse taper connection (IC). Straight (SA) (n = 60) and angulated abutments (AA) (n = 60) were randomly screwed to each connection at different torque levels (n = 10 each): 10, 20 and 30 Ncm. All specimens were subjected to thermal and cyclic loading and the misfit was measured by scanning electron microscopy. Data were analyzed with one-way ANOVA, t-test and Kruskal-Wallis test. Results: Significant differences (p < 0.001) were found between connections and abutments regardless of the torque applied. Morse taper connections with straight and angulated abutments showed the lowest misfit values (0.6 µm). Misfit values decreased as torque increased. Conclusions: The misfit was affected by the type of connection. The type of abutment did not influence the fit in the Morse taper connection. The higher the tightening torque applied the increase in the fit of the implant-abutment interface.

Influence of torsional strength on different types of dental implant platforms

AIM

The study assessed deformation of implant components submitted to torsion tests of 80 and 120 N · cm using an optical stereomicroscope.

MATERIAL AND METHODS

The following 3 types of Titaniumfix conical implant connections (n = 5) measuring Ø 4.0 × 11.5 mm were used: external, internal hexagon and Morse taper connections. The diagonal and lateral measurements of the hexagon implant platform were measured before and after the torsion test.

RESULTS

The torsion test using torque of 80 and 120 N · cm altered the implant dental platforms. All groups presented deformation of implant component after torque of 80 N · cm with no statistical difference among them. During torque of 120 N · cm, a difference in the Morse taper connection in relation to the internal and external hexagon connection was observed. The Morse taper connection implant, followed by the internal hex implant, underwent less deformation. Greater deformation occurred in the external hex implants.

CONCLUSION

For all the implants, high insertion torques deformed the implant platform preventing long-term maintenance and stability of implants.