Abstract
Biological complications can compromise the longevity of a dental implant. Although bacteria biofilm is the only accepted sole aetiology, other potential risk indicators, such as the presence of titanium (Ti) particulate in the peri-implant tissues, are currently under investigation to determine their role in peri-implantitis.
Objectives
This thesis investigates the effect of commonly used mechanical decontamination procedures on a moderately roughened Ti surface. In addition to a comprehensive literature review on the Ti surface alteration induced by mechanical instrumentations, a systematic review, and an in-vitro study were conducted to present the existing evidence and evaluate the size and quantity of Ti particulate that is released from Ti surfaces during common mechanical surface decontamination methods.
Methods and Materials
A PICO framework was used as a frame for the topic and appropriate keywords were searched in EMBASE, via the Ovid and PubMed databases, up to December 2020 to identify all types of studies that evaluated post-instrumentation changes in Ti surface element composition and the physical characteristics of released Ti particles, including the quantity and the size of particles. All types of Ti surface, mechanical decontamination methods, and measuring methods were included.
For the in-vitro study, 140 moderately roughened Ti discs were divided into seven groups (n = 20 in each group). Six groups received mechanical decontamination procedures: ultrasonic scaling with metal tip or polyetheretherketone (PEEK) tip under both low and medium power settings, air-polishing with erythritol powder, Ti brush, and a control group underwent air-water spray using dental triplex. The rinsing solutions were collected for analysis. The mass of Ti was analysed by inductively coupled plasma mass spectrometry (ICP-MS) and Ti particle size was measured by the scanning electron microscope (SEM) with the aid of energy dispersive X-ray spectrometry (EDS) for particle differentiation.
Results
Three studies evaluated the quantity of Ti particulate released during ultrasonic scaling. A significantly higher number of Ti particles and higher Ti weight was found in the rinsing solution of ultrasonic scaling with metal tips in comparison to PEEK plastic tips. Moderately roughened surfaces were found to shed more Ti particles than machined smooth Ti surfaces during instrumentation. Only one study analysed the size of metal particle found in the rinsing solution of ultrasonic scaling with metal tips. No significant
difference in particle size was found between machined, and-blasted and acid-etched (SLA), and a sand-blasted Ti surface (7.57 ± 1.43 μm, 7.57 ± 2.75 μm, and 8.37 ± 2.94 μm, respectively). Furthermore, remnant particles derived from non-metal instruments, including air-polishing powder, have been consistently identified in element composition analyses. However, on a contaminated Ti surface, the elemental profile is mostly altered by the bacterial biofilm rather than remnant deposition of the instruments.
This current in-vitro study demonstrated that ultrasonic scaling with a metal tip generated 34.00±12.54 μg and 34.40±6.08 μg of Ti under low and medium power settings, respectively. This was significantly higher than other instrumentation groups. The mean Ti particle size of the ultrasonic scaling groups ranged from 0.89±0.27 μm to 1.25±0.24 μm. No statistical significance was found in the particle size among ultrasonic scaling groups and the Ti brush group (1.05±0.11 μm), except for ultrasonic scaling using a PEEK
tip where a significantly smaller particle diameter was found in a low power setting (0.89±0.27 μm) compared to a medium setting (1.25±0.24 μm).
Conclusion
Mechanical decontamination of moderately roughened Ti discs produced Ti particulate and surface modification to various extents. Ultrasonic scaling using a metal tip generated the highest amount of Ti with smaller size Ti particles when compared to all other commonly used mechanical surface instruments. The EDS analysis confirmed Ti in PEEK ultrasonic scaling tips. On this basis, it can be suggested that the deterioration of the PEEK ultrasonic scaling tip and the Ti brush, as observed under the SEM, is an additional source of Ti release during Ti surface decontamination.
The size of metal particles identified was found to be within the threshold for phagocytosis. Existing evidence is weak, however, and limited to ultrasonic scaling only. More quality studies with valid outcome measurements for inter-study comparison are needed to answer the PICO question comprehensively. Furthermore, the clinical impact of altered Ti surface element composition requires further investigation.