Quantity and Size of Titanium Particles Released from Different Mechanical Decontamination Procedures on Titanium Discs: An In Vitro Study

Abstract

Complications such as peri-implantitis could ultimately affect the survival of a dental implant. The prevention and treatment of peri-implant diseases require managing bacterial biofilm and controlling environmental risks, including the presence of pro-inflammatory titanium (Ti) particles in the peri-implant niche. Objectives included the evaluation of the size and quantity of Ti particles released from moderately roughened Ti surfaces during common mechanical surface decontamination methods. One hundred and forty moderately roughened Ti discs were divided into seven groups (n = 20 per group); six groups received mechanical decontamination procedures (ultrasonic scaling (US) with a metal tip and poly-ether-ketone (PEEK) under low and medium power settings, air-polishing with erythritol powder, and Ti brush), and the control group underwent air-water spray using a dental triplex. The rinsing solution was collected for Ti mass analysis using inductively coupled plasma mass spectrometry (ICPMS), as well as for Ti particle size and count analysis under scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). US metal tip instrumentation generated 34.00 ± 12.54 μg and 34.44 ± 6.08 μg of Ti under low and medium power settings, respectively. This amount of Ti generation was significantly higher than other instrumentation methods. The mean Ti particle size of the US groups ranged from 0.89 ± 0.27 μm to 1.25 ± 0.24 μm. No statistically significant difference was found in the particle size among US groups and Ti brush group (1.05 ± 0.11 μm), except for US with the PEEK tip, where a significantly smaller mean particle diameter was found at the low power setting (0.89 ± 0.27 μm). Mechanical instrumentation can produce Ti particulates and modify the implant surfaces. US using a metal tip generated the highest amount of Ti with smaller Ti size particles compared to all other commonly used mechanical surface instrumentations. The EDS analysis confirmed Ti in PEEK US tips. It can be suggested that deterioration from the PEEK US tip and Ti brush, as observed under SEM, is an additional source of Ti release during Ti surface decontamination.

Keywords: dental implants; inductively coupled plasma mass spectrometry; instrumentation; peri-implantitis; scanning electron microscopy; titanium.

Figure 1

Commercially pure Grade 4 moderately roughened titanium disc.

Figure 2

Study outline and group allocation. Note: Ti: titanium; USM: ultrasonic scaling with metal tip; USP: ultrasonic scaling with PEEK tip; AP: air-polishing with erythritol powder; ICP-MS: inductively coupled plasma mass spectroscopy; SEM: scanning electron microscope.

Figure 3

Setup of ultrasonic scaling with metal and PEEK tips: miniMaster piezon scaler E.M.S. (A), steel tip P, E.M.S. (B), PEEK Instrument PI, E.M.S. (C), custom instrumentation device (D), horizontal disc platform (E), scaling tip fixed at 15° (F), force controlled at 100 g (G), and enclosure for rinsing solution collection (H).

Figure 4

Setup of air-polishing: Air-Flow handy 3.0^®, E.M.S. (A), Air-Flow Plus erythritol powder, E.M.S. (B), air-polish setup on instrumentation device. (C), nozzle fixed at 90° (D) and 3 mm away from the disc (E), and solution collected within a transparent enclosure (F).

Figure 5

Setup of Ti brush: NiTi Brush Omega, Hans Korea (A), KaVo 16:1 Intra 3624N contra-angle surgical handpiece (B), setting of implant electric motor (600 RPM and 5Ncm torque (C), irrigation volume control (D), and Ti brush fixed at 55° the disc (E).

Figure 6

Filtration setup: Swinnex membrane holder, EMD Millipore Corporation (A), polycarbonate membrane, Isopore, Merck Millipore (B), nitrocellulose membrane, MF-Millipore, Merck Millipore (C), Swinnex assembled to a disposable 6 mL luer-lock syringe (D), sample collected and stored for SEM analysis (E).

Figure 7

Area of interest for SEM analysis (A), data collection using ImageJ (B), and Ti particles represented in black over a white background (C).

Figure 8

Chemical composition of Ti disc and instruments under ×1000 magnification: moderately roughened Ti disc (A,B), ultrasonic metal tip (C,D), ultrasonic PEEK tip (E,F), erythritol powder (G,H), and Ti brush (I,J).

Figure 9

Particles identified from mechanical decontamination procedures: metal tip ultrasonic scaling under ×1000 magnification (A), spectrum 6, Ti (B), spectrum 5, Fe, Cr (C); PEEK tip ultrasonic scaling under ×1000 magnification (D), spectrum 30, Ti (E), spectrum 33, Al, C (F); Ti Brush under ×1000 magnification (G), spectrum 17, Al, Ti (H).

Figure 10

Boxplot of the mean Ti particle size (μm).

Figure 11

Boxplot of mean Ti particle count.

Figure 12

Boxplot of Ti mass (μg).