Surface measurement made with the Dropometer
Surface wettability was reported as water contact angle (θ) measured on instrumented SLA titanium surfaces.
Client Citation Analysis
Effect of mechanical instrumentation on titanium implant surface properties
This study evaluates how four rotary brush decontamination approaches alter SLA titanium surface properties, using Dropometer-based water contact angle (wettability) alongside morphology, roughness, and elemental composition measurements.
At-a-Glance Summary
How the paper credits the instrument
"To evaluate the surface wettability, a droplet shape analyser (Dropometer, Droplet Lab, Canada) was employed to determine the contact angles." / "The images were analysed using dedicated software that utilises a polynomial fit to calculate the contact angle on the right and left sides." — Section 2.3.4, Surface wettability. The instrument is named in the first of these sentences; the paper does not state a model number or software version.
How the contact-angle data were used in the study
Contact angle results were presented in Table 2 and Fig. 6 and used to compare wettability differences across rotary brush decontamination groups relative to the control. The authors interpret wettability changes alongside the study's surface topography and composition characterisation to describe how mechanical instrumentation modifies implant-relevant surface properties.
Replication / reliability statement
"Contact angle measurements were taken from five discs in each group, with five repeat measurements obtained for each disc (n=125, 25 measurements per group). The mean contact angle was then computed for each group to yield a representative value for analysis." (Section 2.3.4). Table 2 reports median (range) values, because the paper found that "normality assumptions were violated" and analysed the data with Kruskal-Wallis and Dunn-Bonferroni tests. Every contact angle value quoted on this page is a median.
What the Dropometer did, and what it did not do
The Dropometer measured water contact angle on the treated discs, producing Fig. 6 and one of the seven data columns in Table 2 — one of the paper's six figures. It was not the primary measurement instrument. Surface damage was established by FE-SEM (Fig. 4), surface chemistry by SEM-EDX (Fig. 5), and the other six Table 2 columns (Sa, Sz, Ssk, Sku, Sdq, Sdr) by optical profilometry. Wettability is the fourth and last of the study's four stated objectives.
Paper Details
Title
Effect of mechanical instrumentation on titanium implant surface properties
Authors
Mohammed Alabbad; Nick Silikas; Andrew Thomas
Journal
Dental Materials
Year
2025
Volume
41
Pages / Article
383–390
License
CC BY
Funding & interests
Funded by the Saudi Arabian Cultural Bureau in London, UK, in support of the first author; the paper states "The funder had no role in the study design, data collection and analysis, decision to publish, or manuscript preparation." Authors are at the University of Manchester (Division of Dentistry, Department of Materials, Photon Science Institute) and King Abdulaziz University, Jeddah. Droplet Lab appears in no funding, affiliation or acknowledgement statement. Neither do the four brush manufacturers (Labrida AS, Neo Biotech, HANS and SOWDANE); their brushes were the products under test, and the paper reports significant surface alterations with three of the four. The Dropometer is named only in the Methods (Section 2.3.4). This funding statement appears under the paper's Declaration of Competing Interest heading.
Study type & scope
In vitro laboratory study on Grade 5 Ti 6Al-4V discs (14.5 mm diameter, 2 mm thick) prepared to a sandblasted, large-grit, acid-etched (SLA) surface. Not a clinical study and not performed on dental implants. The paper's own limitations: "titanium discs were used instead of dental implants… as working on implants with screw threads can be challenging" and "only SLA titanium surfaces were examined, potentially limiting the applicability of our findings to other implant surfaces."
What Was Measured
Surface / interfacial measurement (Dropometer)
Surface wettability was measured as contact angle (θ) using ultrapure water droplets deposited on treated SLA titanium surfaces and analysed by droplet shape analysis.
Other surface measurements
Surface morphology/topography was evaluated by field emission scanning electron microscopy (FE-SEM) and gross surface photography. Surface elemental composition was measured by SEM-EDX, and surface roughness was measured by 3-D optical profilometry using three-dimensional parameters (Sa, Sz, Ssk, Sku, Sdq, Sdr) following ISO 25178–2:2012.
Gross surface photographs
EOS 600D (CANON, Japan)
Surface morphology/topography
Field Emission Scanning Electron Microscope (FE-SEM) (Quanta FEG 250, FEI Company, Hillsboro, Oregon, USA)
Surface elemental composition
Energy-Dispersive X-ray Spectrometry (SEM-EDX; X-Max, Oxford Instruments, Oxford, England)
Element mapping software
Aztec 3.3 (Oxford Instruments, Oxford, England)
Surface roughness
3-D optical surface profilometer (TopMap Micro.View, Polytech, Baden-Württemberg, Germany)
Roughness analysis software
TMS 4.2 (Polytech, Baden-Württemberg, Germany)
Surface wettability (contact angle)
droplet shape analyser (Dropometer, Droplet Lab, Canada)
Role of the Dropometer
The authors used a droplet shape analyser (Dropometer, Droplet Lab, Canada) to determine water contact angles as a measure of surface wettability. An automated dispenser deposited a 3 µl ultrapure water droplet onto each treated surface at 23 °C, images were captured after 5 s, and dedicated software applied a polynomial fit to calculate contact angles on the right and left sides of the droplet; group mean contact angles were then computed as representative values for analysis.
In this study, Dropometer-derived contact angles were used to compare how different rotary brush decontamination methods changed wettability relative to the untreated control. The correlation analysis in the paper was applied to surface roughness parameters ("a strong positive correlation between Sa and Sdr (rs = 0.891, p<0.001)"). The authors discuss the link between wettability and the topographic and chemical changes in the Discussion: "Interdependencies exist among implant surface properties; thus, modifying one property results in the alteration of others. Based on this, it is plausible to find that IB had the greatest impact on surface wettability because it has significantly changed surface topography and elemental composition."
Bring This Measurement Into Your Lab
If you compare wettability of titanium or other implant surfaces after treatment, we can show you a sessile drop contact angle workflow on your samples.
Key Findings
Contact angle differed significantly across decontamination groups
"Results for the contact angle measurements (θ) are presented in Table 2 and Fig. 6. The Kruskal-Wallis test indicated significant differences between the decontamination groups (p<0.001)." (Section 3.4). Kruskal-Wallis was used because "normality assumptions were violated"; post hoc comparisons were Dunn-Bonferroni, and all reported values are medians with ranges.
LB wettability matched the control
Further analysis showed that the LB group's contact angle was similar to the control (p > 0.05), with medians of 85.9° (range 17.0) for LB and 84.8° (range 21.0) for the control in Table 2. This is the study's only null result on wettability, and it is consistent with the paper's conclusion that the Labrida BioClean brush "demonstrated minimal impact on surface properties". LB matched the control on Sa, Sz, Ssk and Sku but showed higher Sdq and Sdr, and EDX showed slightly raised carbon.
IB and PIB showed the largest wettability increase
The paper's sentence covers three groups, not two: "the IB, NiTiB, and PIB groups exhibited significantly higher wettability (p<0.05) compared to the control, indicated by their significantly lower contact angles. The IB and PIB groups reduced the contact angle to a similar extent, while the NiTiB group reduced it to a lesser degree." Table 2 medians (range): IB 67.45° (12.50), PIB 65.3° (25.7), against a control of 84.8° (21.0). Note that PIB's median is the lowest in the study, slightly below IB's; the paper reports the two reductions as similar.
NiTiB produced a smaller contact-angle reduction
The NiTiB group was reported as significantly more wettable than the control (p < 0.05) but reduced contact angle to a lesser degree than IB and PIB (Table 2 median: 81.0°, range 18.3). Table 2's lowest median contact angle is PIB (65.3°), with IB at 67.45°. The Results section reports the IB and PIB reductions as similar, and the Discussion relates the IB wettability change to its larger changes in surface topography and elemental composition.
The paper's conclusion: three of four brushes altered the implant surface
The study's stated conclusion is about surface damage, not wettability: "Mechanical decontamination of implant surfaces utilising rotary brushes can alter implant surface properties. The brush material, design, and decontamination parameters, such as rotational speed, influence their effect on implant surface properties. i-Brush1, NiTiBrush Nano, and peri-implantitis brushes induced significant alterations in titanium implant surface properties, while Labrida BioClean brush demonstrated minimal impact on surface properties." The null hypothesis — that rotary brushes do not alter implant surface properties — was rejected. Contact angle was one of four measurements supporting that conclusion, alongside SEM morphology, EDX composition and optical profilometry.
Brush-derived elements were detected on some treated surfaces (SEM-EDX, Fig. 5)
EDX found that the i-Brush1 group's surface was no longer predominantly titanium: "SEM-EDX of the surfaces instrumented with IB reveal the presence of cobalt (Co), chromium (Cr), and molybdenum (Mo) as predominant elements on the surface, alongside iron (Fe), carbon (C), aluminium (Al), and traces of silicon (Si)" — deposited from the brush's stainless steel bristles. Nickel was detected on the NiTiBrush Nano surfaces, reflecting its nickel-titanium bristles, and the Labrida group showed raised carbon from marine-polymer bristle breakage. The Discussion offers this combination of chemical and topographic alteration as a plausible explanation for the wettability change: IB "had the greatest impact on surface wettability because it has significantly changed surface topography and elemental composition."
All three metallic brushes flattened the SLA surface (optical profilometry, Table 2)
Sa, Sz, Ssk and Sdr fell significantly in the IB, NiTiB and PIB groups (Kruskal-Wallis p < 0.001 for every parameter), while Labrida BioClean matched the control on Sa, Sz, Ssk and Sku and showed higher Sdq and Sdr. Sa dropped from a control median of 1.53 µm to 0.88 µm for IB, and Sdr from 121.10% to 63.27%; the paper reports "a strong positive correlation between Sa and Sdr (rs = 0.891, p<0.001)". SEM showed parts of the SLA honeycomb structure replaced by flattened, scratched islands, with loose abraded titanium particles on the IB, NiTiB and PIB surfaces. The authors note this "can modify cellular responses, which could negatively impact the re-osseointegration process," that "scratches and grooves created by brushes could lead to plaque attachment," and that titanium particles "may contribute to undesirable biological events, such as the development of peri-implantitis and osteolysis."
Figures & Visuals
What it shows
Shows representative water droplets used for contact-angle assessment of surface wettability across the decontamination groups.
What it shows
Lists median (range) values by group for six optical-profilometry roughness parameters — Sa, Sz, Ssk, Sku, Sdq, Sdr — plus one column of Dropometer contact angle (θ°). Contact angle is one of the table's seven data columns. Superscript letters mark statistically distinct groups under Dunn-Bonferroni post hoc testing; in the contact angle column the control and LB share letter A, IB and PIB share B, and NiTiB is C.
What it shows
Provides FE-SEM images illustrating how rotary brush instrumentation altered SLA surface morphology, which the paper discusses alongside wettability results.
What it shows
Summarises elemental composition (wt%) after mechanical instrumentation. LB, PIB and NiTiB broadly match the control (Ti, Al, V, O), with raised carbon after LB from polymer bristle breakage, slightly elevated titanium after PIB and NiTiB from abraded particles, and trace nickel after NiTiB. The IB group is the outlier: cobalt, chromium and molybdenum appear as predominant surface elements, with iron, carbon, aluminium and traces of silicon — stainless steel transferred from the brush bristles.
Why It Matters
The authors frame peri-implantitis decontamination as a process that can modify implant surface properties, and they evaluate these changes by combining wettability (contact angle) with surface morphology, roughness, and elemental composition measurements. Within this approach, the contact angle data provide a direct, quantitative comparison of how different rotary brush systems influence surface wettability of SLA titanium.
The authors are explicit that the clinical value of the wettability change is unproven. Their Discussion reads: "Using metallic rotary brushes for implant surface decontamination represents a potential biological benefit as it improves implant surface wettability. However, most of the clinically marketed dental implants are hydrophobic, and the impact of enhancing the implant wettability on re-osseointegration is still unclear." They also note that the same instrumentation smoothed the surface, which "can modify cellular responses, which could negatively impact the re-osseointegration process," and deposited loose titanium particles that "may contribute to undesirable biological events, such as the development of peri-implantitis and osteolysis." The measurement is a characterisation result, not a demonstration of clinical benefit.
The study's own stated limits: "This study has certain limitations. Firstly, titanium discs were used instead of dental implants to ensure more precise surface characterisation, as working on implants with screw threads can be challenging. Additionally, only SLA titanium surfaces were examined, potentially limiting the applicability of our findings to other implant surfaces." All wettability values were taken on flat Grade 5 Ti 6Al-4V discs, five per group, at a single time point 5 s after droplet deposition. Median contact angles across all groups, control and treated, were between 65.3° and 85.9° (Table 2).
Expert Perspective
Practical Takeaways
Reported contact-angle workflow
The study reports a defined protocol using a droplet shape analyser (Dropometer, Droplet Lab, Canada) with a 3 µl ultrapure water droplet, imaging at 5 s, and polynomial-fit analysis of left/right angles.
Brush choice shifts wettability outcomes
Contact angle results show that wettability changes depended on the rotary brush system, with IB, NiTiB and PIB reported as significantly more wettable than the control (p < 0.05). In this study the brushes that raised wettability were the same brushes that flattened the SLA topography and, for IB and NiTiB, left brush-derived elements on the surface, so in this study the wettability change occurred together with other surface alterations.
Quantitative group comparison via Table 2
The paper reports median (range) contact angles for each group — CTR 84.8° (21.0), LB 85.9° (17.0), IB 67.45° (12.50), NiTiB 81.0° (18.3), PIB 65.3° (25.7) — to compare decontamination methods on a common wettability metric. The ranges are as informative as the medians: PIB has both the lowest median and the widest spread in the study, while IB has the narrowest.
Wettability interpreted alongside surface characterisation
The contact angle results are discussed in the context of FE-SEM morphology, 3D roughness parameters, and SEM-EDX elemental composition to describe how mechanical instrumentation alters multiple surface properties.
Frequently Asked Questions
What did the Dropometer measure in this study?
The authors used a droplet shape analyser (Dropometer, Droplet Lab) to measure water contact angle on SLA titanium discs after rotary brush instrumentation. An automated dispenser placed a 3 µl ultrapure water droplet at 23 °C, an image was taken after 5 s, and software applied a polynomial fit to the left and right sides of the drop. Five discs per group were tested with five repeats each (25 measurements per group).
What contact angles were reported?
Table 2 gives median (range) contact angles of 84.8° (21.0) for the untreated control, 85.9° (17.0) for Labrida BioClean (LB), 67.45° (12.50) for i-Brush1 (IB), 81.0° (18.3) for NiTiBrush Nano (NiTiB) and 65.3° (25.7) for the peri-implantitis brush (PIB). LB was similar to the control, while IB, NiTiB and PIB had significantly lower contact angles (p < 0.05), meaning higher wettability.
What do the authors conclude about the wettability change?
The authors suggest that i-Brush1 had the greatest impact on wettability because it also significantly changed surface topography and elemental composition. They describe improved wettability as a potential biological benefit, but note that its impact on re-osseointegration is still unclear.
What did the study not measure?
This was an in vitro study on flat Grade 5 Ti 6Al-4V discs with an SLA surface rather than on threaded dental implants, a choice the authors explain in their limitations. Contact angle was taken as a single static reading 5 s after deposition, so advancing and receding angles were outside its scope.