Strength of titanium-zirconium alloy implants with a conical connection after implantoplasty

Statement of problem

Peri-implantitis occurs around dental implants, and implantoplasty has been used to address this ongoing disease; however, the changes to the physical properties of an implant after implantoplasty have not been well documented.

Purpose

The purpose of this in vitro study was to determine the effect of implantoplasty on fracture strength and the load required for plastic deformation after cyclic fatigue on dental implants.

Material and methods

Twenty-six titanium/zirconium (TiZr) alloy implants (Roxolid Bone Level Implant; 4.1×10 mm) were embedded with 50% thread exposure and divided into 4 groups based on whether they had implantoplasty treatment by using different diamond rotary instruments and/or cyclic loading at 250 N for 2 million cycles: C0 (control, no cyclic loading), T0 (test, no cyclic loading), CM (control, cyclic loading), and TM (test, cyclic loading). After implantoplasty and/or cyclic loading, all implants underwent a load-to-failure test. The maximum fracture strength (FS) and load required for the onset of plastic deformation (PD) were recorded in Newtons. One-way ANOVA and nonparametric comparisons with control by using the Dunn and Wilcoxon method for joint ranking were used for statistical analysis.

Results

The mean ±standard deviation FS for C0, CM, T0, and TM was 1465.2 ±86.4 N, 1480.7 ±64.1 N, 1299.3 ±123.8 N, and 1252.1 ±85.7 N, respectively. The mean ±standard deviation load for onset of PD for C0, CM, T0, and TM was 860.2 ±88.1 N, 797.0 ±130.5 N, 776.5 ±181.8 N, and 631.3 ±84.5 N, respectively. The TM group had a significantly lower FS and PD than the C0, CM, and T0 groups (P<.05)

Conclusions

Both fracture strength (FS) and the onset of plastic deformation (PD) were significantly reduced after a TiZr alloy implant received implantoplasty and cyclic loading.