Materials

Reagents and solvents were purchased from Sigma-Aldrich (Dorset UK). Commercially pure grade 4 titanium implants (n = 3) were purchased from Straumann (Sussex UK, Model number 021.4512, bone-level implant diameter 4.1 mm, Regular CrossFit®, SLA® 12 mm Roxolid®) (Fig. 1a). Grade 5 Ti-6Al-4 V titanium alloy implants were purchased from Biohorizons (Berkshire UK, n = 3, model number PBR50105, RBT 5.0 × 10.5 mm, 5.7 Platform) (Fig. 1d).

The methods in this study follow SPQR (standards for reporting qualitative research) guidelines.

Mock implantoplasty protocol

Implants were secured with forceps held using table clamps. In order to minimise variations in the pressure applied during the implantoplasty, all procedures were completed by one operator. A handpiece (W&H, Alegra dental turbine handpieces TE-98 Led G) was used with motor set at 50,000 rpm. Diamond burrs (Diatech G856.314.021.9ML-200453AA) were limited to single use for 5 min on each implant. Particles released from implants following implantoplasty were collected, weighed and analysed for size, composition and ion release characteristics.

Dynamic light scattering

Dynamic light scattering (DLS) was performed using a Malvern Zetasizer (instrument 2000) instrument to determine the size distribution of released implant particles. The instrument is equipped with a HeNe laser (λ = 632.8 nm) with a backscattering detection angle of 173°. Particle size was also measured using Malvern Mastersizer (Malvern Panalytical Ltd, Royston, UK). Measurement duration (15 min) and number of sub-runs (3) were automatically adjusted by the instrument. Particles were suspended in 70% ethanol at a concentration of 5 mg ml⁻¹ and sonicated for 15 min prior to each measurement.

Scanning electron microscopy

Particle samples were dried in a 60 °C oven and secured to an aluminium sample holder with carbon tape and coated with 10 nm gold. Images were acquired using Zeiss Sigma-300 scanning electron microscope (SEM). For energy dispersive x-ray spectroscopy (EDX) analysis, samples were secured with silver conductive paint.