Influence of the Ultimate Torsion on the Geometry of Dental Implants

Abstract

This study evaluated the profile of implants subjected to torsion test. Four types of implants (Conexão ® ) were analyzed: Master Porous (MP -external hexagon, cylindrical, double-porous surface implants; 11.5 X 3.75 mm), Master Screw (MS -external hexagon, cylindrical, machined implants; 11.5 X 3.75 mm), Conect Conic (CC -external hexagon, cylindrical, machined implants; 11.5 X 3.5 mm) and Master Conect AR (CA -internal hexagon, cylindrical, double-porous surface implants; 11.5 X 3.75 mm). The Nikon ® model C profile projector was used for the analysis before and after torsion test with a Mackena ® model MK-20XX digital torque meter. The measures analyzed in the profile of implants were: diameter and height of the platform, diameter of the screw/platform connection, angle of the screw/platform connection, external diameter, internal diameter, thread pitch, height and length of the thread. Statistical analysis was performed using ANOVA and Tukey test at 5% significance level. The torsion test caused a visible deformity on the external implant profile. There was a statistical difference among the implants before and after torsion (p<0.05) for the variables: platform diameter, platform height, diameter of the screw/ platform connection and length. Changes were observed in platform height of CC and CA, fracture of CA implants, fracture of the MP and MS assembler/connectors, and internal thread stripping of CC. Thus, it was concluded that excessive or some unadvised torque by the manufacturer can lead to changes in different geometric measurements of implants.

Is the internal connection more efficient than external connection in mechanical, biological, and esthetical point of views? A systematic review

“…Weng et al [43]; Weng et al [44] Evaluation of different surgical approaches (submerged and/or nonsubmerged implants) Steinebrunner et al [45] Evaluation of fatigue and fracture strength of different implant-abutment connections Bernardes et al [46] Comparison of two types of vertical compressive load from different implant-abutment interfaces Novaes Jr et al [47]; Barros et al [48] Evaluation of different interimplant distances and placement depth of implants restored with platform switch Rodríguez-Ciurana et al [49] Evaluation of biologic width of abutments with different diameters Nishioka et al [50] Comparison between machined and plastic copings Jesus Tavarez et al [51] Evaluation of vertical misfit alterations of the implant/abutment interface when subjected to cyclic loading Nishioka et al [52] Evaluation of different abutment designs and fixture alignments Pieri et al [53] Comparison between implants restored with platform switch or conventional abutments Freitas Jr et al [54] Evaluation of screw-retained and cement-retained prostheses Pessoa et al [55] Comparison between different commercially available designs of one connection type of immediately placed implants Oliva et al [56] Evaluation of full-arch rehabilitation with three implants (all on three) Diez et al [57] Evaluation of the implant-abutment interface with diamond-like carbon-coated screws Arnhart et al [58] Evaluation of a variable thread dental implant design Freitas Jr et al [59] Evaluation of reliability and failure modes of different abutments used for anterior restorations Tang et al [60] Investigation of mechanical characteristics of different implant-abutment interface designs Rack et al [61] Evaluation of the effect of cyclic loading at implants and abutment deformation Kopp et al [62] Did not report the type of connection used Gehrke [63] Evaluation of the resistance to static fatigue implants with various connections at different crown heights Teixeira et al [64] Evaluation of different profiles of implants submitted to torsion test…”

A 3-D Finite Element Study of the Influence of Crown-Implant Ratio on Stress Distribution

“…Some studies describe approaches to reduce the stress transfer to bone tissue, including different diameters and lengths of implants, occlusal patterns, veneering materials, prosthetic components, implant-crown ratio, load type, material properties of implants, quality and quantity of surrounding bone and surface characteristics of implants (3,(7)(8)(9)(10).…”

Effects of insertion torque on the structure of dental implants with different connections: Experimental pilot study in vitro

“…However, identifying the functional and mechanical limitations of implant systems is essential for the long-term success of the restoration [ 9 ]. During the insertion of implants into the bone tissue and the application of the torque to obtain the initial stability, the sets (implant and insertion driver) are subjected to torsional forces, which depending on their intensity can affect the structure of these parts [ 10 , 11 ]. The titanium implants are metallic pieces that have different limited values of resistance to the loads and/or external forces applied on their structure.…”