Matrix and O-ring dimensions influence retention forces in one-piece MDIs, says Study

Recent research published in the International Journal of Prosthodontics has revealed that matrix and O-ring dimensions have a significant influence on retention forces in one-piece mini dental implants (MDIs).

Literature reads that the evolution of retention forces in one-piece mini dental implants (MDIs) retaining implant overdentures (IODs) is of major importance, as the male parts cannot be exchanged, due to the implant design. However, analysis of Retention Force Reproducibility Using Different Pristine Matrix-O-Ring Combinations is still unlcear.

Abou-Ayash S and colleagues carried out the present study to analyze the influence of pristine matrix and O-ring dimensions on retention force and reproducibility in single one-piece mini dental implants (MDIs) with ball patrices under in vitro conditions.

Three different matrix and O-ring combinations (MH1-MH3) were evaluated (n = 50 per group) on 1.8-mm-diameter implants. The matrices were manually mounted on the implants and were subsequently removed in a vertical linear manner using a metal pin with two strain gauges, recording the maximum force during disconnection.

After five disconnections, the O-rings were exchanged, and the mean retention force was calculated, resulting in 50 values for each matrix and O-ring combination. Mean retention forces, SDs, and 95% CI were calculated. Analysis of variance was used to test the global differences and post hoc pairwise comparisons were subsequently applied. The level of significance was set to P < .05.

The following results were observed-

ANOVA (global P < .0001) and pairwise comparisons (all P < .0001) demonstrated statistically significant differences among the three different matrix and O-ring combinations, with mean values of 5.18 N (MH 1), 6.73 (MH 2), and 9.08 (MH 3).

Within each combination, retention force variations of > 1 N could not be demonstrated; ie, by exchanging O-rings, a similar retention force can be reestablished.

Hence,  authors concluded that "Matrix and O-ring dimensions have a significant influence on retention forces in one-piece MDIs. Pristine O-rings demonstrated highly reproducible initial retention forces in all matrices."