In Vitro Fit Accuracy of Conical Connection Implant System Components - Part 1: Two-Dimensional Tolerance Displacement.

PURPOSE: This in vitro study evaluated the two-dimensional (2D) tolerance displacement of six conical connection implant systems and investigated the effect of varying tightening torque levels at four implant component connections.

MATERIALS AND

METHODS

Six implant systems were tested using ten implants, ten replicas, ten impression copings and ten abutments at four component connections: implant-impression coping (I-C), replica-impression coping (R-C), replica-abutment (R-A), and implant-abutment (I-A). A coordinate measuring machine was used to compute 2D tolerance displacement (dr) between upper (C / A) and lower (I / R) components, representing 2D positional deviation. Torque magnitudes of 5, 10, and 15 Ncm were applied at I-C, R-C, and R-A, while manufacturer-specified torque values were used for I-A. For I-C, R-C and R-A, the data was analyzed using mixed analysis of variance (ANOVA) to evaluate the effects of implant system and torque magnitude on dr. For I-A, one-way ANOVA was conducted to evaluate differences in dr among the specific system-abutment combinations at their respective manufacturer-specified torque values.

RESULTS

Overall mean dr ranged from 2.7 ± 1.3 μm (CONR-A, 10 Ncm) to 23.7 ± 10.4 μm (MEGR-A, 10 Ncm). Mean dr ranged from 4.0 ± 2.7 μm (DENI-C, 10 Ncm) to 15.2 ± 8.8 μm (STRI-C, 10 Ncm) for I-C; from 3.9 ± 1.9 μm (DENR-C, 5 Ncm) to 13.0 ± 11.3 μm (STRR-C, 10 Ncm) for R-C; and from 2.7 ± 1.3 μm (CONR-A, 10 Ncm) to 23.7 ± 10.4 μm (MEGR-A, 10 Ncm) for R-A. Mixed ANOVA demonstrated no significant effects of torque magnitude or torque and implant system interaction for I-C, R-C, or R-A, but significant differences among implant systems were observed for all three connection types. For I-C, STR exhibited greater dr than ANT and DEN; for R-C, MEG exhibited greater dr than DEN and OSS; and for R-A, CON exhibited lower dr than all other systems. Significant differences among systems were also observed for I-A (P < 0.001).

CONCLUSIONS

Statistically significant differences were observed among implant systems. Mean dr of all conical connection implant system components evaluated ranged from 2.7 to 23.7 μm. These measured displacements are interpreted to be small in magnitude, but their clinical significance remains uncertain.