Dental caries and periodontal disease, which rank among the most prevalent ailments afflicting humanity, are intricately associated with bacterial adhesion and the formation of biofilms on both natural and restored tooth substrates. Alterations in the appearance such as the manifestation of white lesions, demineralization of enamel in proximity to orthodontic braces, dental caries, or the onset of periodontal disease represent frequently encountered complications in the context of orthodontic interventions employing fixed appliances.
Dental caries, a multifaceted ailment, is subject to the influence of a multitude of factors. Its pathogenesis is intricately linked to the presence of cariogenic microorganisms such as
The diverse elements comprising fixed orthodontic appliances provide an optimal environment for the retention of food debris and exert a substantial influence on the proliferation of bacterial plaque due to their uneven surface morphology. The accumulation of plaque in retention areas exposes teeth to an increased risk of demineralization of the enamel and intensifies the effects of pre-existing, initial caries changes. Following standard orthodontic treatment, it has been observed that approximately 50% of patients may experience enamel demineralization and periodontal disease [7–9]. A research investigation carried out by Marcusson et al. revealed that the incidence of white spot lesions exhibited a rise, ascending from 7.2% prior to the intervention to a spectrum spanning from 24% to 40.5% following the intervention, contingent upon the specific bonding agent utilized [10]. Certain teeth, such as the lateral upper incisors, lower canines, and first molars, tend to be more susceptible to caries. Notably, demineralization during orthodontic treatment can be detected as early as four weeks into the procedure [8, 10]. To address this issue, an encouraging approach involves the utilization of coatings that possess bacteriostatic/bactericidal properties, thereby reducing bacterial adhesion to biomaterials. With the emergence of antibioticresistant strains of bacteria, certain metals, particularly in the form of nanoparticles, have gained attention. Nanoparticles can be used both in combination with dental materials and by coating their surfaces to reduce microbial adhesion and prevent caries.
Coatings are one of the most common types of antimicrobial medical device technologies seen in the research literature. Antiadhesive coatings are designed to prevent the formation of the first stage of biofilm colonization and eliminate the threat from the very beginning. Bacteria can adhere and grow on natural and synthetic surfaces in an aqueous environment [11]. Fixed orthodontic wires are affixed to the dentition via brackets, thereby impeding accessibility to the dental surfaces necessary for adequate oral hygiene maintenance. This phenomenon facilitates the adherence of bacterial colonies and the ensuing development of dental plaque, consequently elevating the susceptibility to demineralization, dental caries, and the initiation of periodontal pathology [9]. In order to protect against the cariogenic effect of bacteria, a wide range of agents is used, from natural polymers to coatings made of metal nanoparticles [12–14].
According to the ISO (International Organization for Standardization), nanoparticles are materials with remarkable properties that range in size from 1 to 100 nm and have been widely used as disinfectants in water, hospital environments, as food preservatives, and to coat medical devices [15, 16]. Upon achieving nanometer-scale dimensions, materials undergo modifications in their inherent characteristics, encompassing alterations in hardness, chemical reactivity, biological activity, and active surface area. This phenomenon is particularly pronounced in the case of metallic nanoparticles, wherein antimicrobial efficacy experiences augmentation attributable to the combined effects of diminished size and an elevated surface-to-volume ratio [17]. This affords enhanced interaction with the microbial membrane, thereby augmenting the biocompatibility of the substrate material. Certain metallic nanoparticles, namely zinc oxide (ZnO), titanium dioxide (TiO2), and silver (Ag), find utility within the realm of healthcare by virtue of their antimicrobial properties [18].
TiO2 is renowned for its exceptional biocompatibility and has found extensive application in the manufacturing of medical apparatus. Research investigations have substantiated that TiO2, when in the anatase crystalline phase, exhibits commendable proficiency in the oxidation and disintegration of diverse biological entities, encompassing bacteria, viruses, fungi, algae, and cancer cells [19]. Laboratory experiments investigating the antibacterial and antiadherent properties of TiO2 have shown reduced bacterial adhesion on TiO2-coated surfaces [20], as reported by Fatani et al. in 2017. Consequently, utilizing the photocatalytic and antiadhesive characteristics of TiO2 in clinical settings can be beneficial in preventing bacterial adhesion and the growth of bacterial colonies around orthodontic instruments. To enhance the bactericidal properties, TiO2:Ag coatings have been developed that incorporate silver to further augment the disinfection capabilities of TiO2 anatase [19, 21].
Silver nanoparticles are known for their antibacterial activity, relying on producing reactive oxygen species in bacterial cells, damage to the bacterial cell walls and cytoplasmic membranes, and interruption of nucleic acid replication [22]. Additionally, antibacterial silver nanoparticles’ efficacy is ensured by their nanoscale size and large surface area ratio to volume [23]. The in vitro antimicrobial, antiviral, and antifungal efficacy of silver nanoparticles (AgNPs) has been substantiated through multiple investigations. AgNPs have exhibited notable effectiveness against a spectrum of microorganisms, including
The utilization of thin film coatings represents a highly efficacious strategy within the realm of surface modification techniques aimed at enhancing the performance of metallic orthodontic archwires. Within the array of techniques employed for the fabrication of thin films, the sol-gel deposition method is distinguished by numerous advantages, including its notable simplicity and uniformity, facilitating comprehensive coverage of intricate structures [26, 27].
Orthodontic wires covered with a functional coating are used in the oral cavity environment. Hence, their use is to reduce the risk of caries via evaluation of their antibacterial properties in a carbohydrate-rich environment. This study aimed to assess the antibacterial and antiadherent characteristics of stainless steel orthodontic archwires with surface modifications of TiO2 and TiO2:Ag in the presence of sucrose. The research focused on the evaluation of these modified wires’ effects on
The 304V stainless steel wires (70% Fe, 19% Cr, 9% Ni, 1.5% Mn, 0.5% Si) were provided by the manufacturer of orthodontic wires (Adenta GmbH). Initially, the wires had a rectangular crosssection with dimensions of 0.016 × 0.022 inches. To prepare the wire samples, they were subjected to a cleaning process involving immersion in acetone and distilled water for a duration of 15 min, while employing an ultrasonic bath [28]. The surfaces of the stainless steel orthodontic wires underwent a modification process using a sol-gel thin film dipcoating technique, which involved coating them with TiO2 and TiO2:Ag. For the purpose of the microbiological investigation, the wire samples underwent autoclaving at 121◦C under steam pressure of approximately 15 pounds per square inch for a duration of 15 minutes.
The sol-gel synthesis was divided into two parts: the preparation of TiO2 sol and nano-TiO2:Ag sol. In the formulation of a titanium dioxide (TiO2) solution, 6 ml of titanium (IV) isopropoxide (97%, Aldrich) were conjoined with 85 ml of isopropanol (Eurochem BDG, Poland), and 0.5 ml of acetic acid (99%, Aldrich). To ameliorate surface topography, 1 wt% of polypropylene glycol (PPG, molar mass = 1000, Alfa Aesar) was incorporated into the TiO2 solution. The resultant amalgamation was subjected to agitation using a magnetic stirrer at ambient temperature for a duration of 3 hours. Thereafter, the agitated solution was permitted to undergo maturation for a period of 24 hours at 4◦C [29].
In order to formulate the nano-TiO2:Ag sol, 1 gm of silver nitrate (AgNO3; Sigma-Aldrich) was dissolved in a solution comprising 2.4 ml of deionized water, 10 ml of acetic acid, and 12 ml of isopropanol. The resultant solution was then amalgamated with the TiO2 precursor solution at ambient conditions for a duration of 3 hours, employing a magnetic stirrer [30].
The dip-coating technique was used to apply a protective layer onto the stainless steel wires. Each individual orthodontic wire was submerged within the sol solution for a duration of 1 minute and subsequently withdrawn at a consistent velocity of 65.8 millimeters per minute, thereby ensuring uniform coverage. The coated wires were subsequently subjected to a drying phase lasting 60 minutes at a temperature of 120◦C, with a controlled thermal ramp of 0.5◦C per minute. This procedure was iterated twice to achieve a thicker thin film. Ultimately, the coated wires were subjected to an annealing process for a duration of 120 minutes at 500◦C, employing a thermal transition rate of 1◦C per minute, all conducted within the laboratory’s ambient environmental conditions. After annealing, the linear segments of orthodontic wires were severed into 1–0 cm-length specimens. The details of the final subgroup of the studied material can be found in Table 1.
Various categories of orthodontic wires that have undergone surface modifications are utilized in microbiological examinations
The experimental group included stainless steel orthodontic archwires coated with a functional thin film of TiO2:Ag. | |
The experimental group consisted of stainless steel orthodontic archwires with a base coating of a thin TiO2 film. | |
The control group comprised stainless steel orthodontic archwires without any coating. |
The coatings were subjected to testing using a specific strain of
The researchers conducted an experiment to assess the ability of
The experiment was designed with the primary objective of evaluating the capacity of
To facilitate the visualization of biofilm formation, orthodontic archwires were subjected to exposure with
Statistical analyses were undertaken employing the TIBCO Statistica package to scrutinize the hypotheses postulated within the confines of this research. The package was used to examine basic descriptive statistics of the quantitative variables under investigation, as well as to assess the normality of their distribution using the Shapiro-Wilk test. This test is widely recognized as the most reliable method for checking the normality assumption of a random variable. It is advantageous because of its high statistical power, lending it a greater probability of detecting departures from the null hypothesis compared to other similar tests.
A series of one-way analysis of variance (ANOVA) tests were performed in a between-group design. In cases where the assumption of equal variances across groups was violated, Welch’s ANOVA was employed as an alternative.
To assess the homogeneity of variances across the study groups, Levene’s test was used. Furthermore, after the primary analysis, post hoc examinations were performed employing the Newman-Keuls procedure to meticulously assess and juxtapose distinctions among the cohorts under investigation. The statistical analysis is included in Section 7, supplementary materials.
Firstly, the quantitative variables under analysis were subjected to basic descriptive statistics. The normality of the distribution of these variables was assessed through the application of the Shapiro-Wilk test.
Table 2 provides a comprehensive overview of the fundamental statistical characteristics for the examined quantitative variables in our study, particularly focusing on experiments involving the presence of sucrose for three different groups of orthodontic archwires: coated with TiO2:Ag (A), coated with TiO2 (B) and uncoated (C) wires. The symbol ‘+’ denotes the addition of sucrose to the environment.
Fundamental descriptive statistics for the examined quantitative variables (experiment with sucrose)
N | M | Me | SD | Sk. | Kurt | Min. | Maks. | W | p | |
---|---|---|---|---|---|---|---|---|---|---|
A+ | 10 | 4.31 | 4.27 | 0.30 | −0.38 | 0.78 | 3.72 | 4.75 | 0.95 | 0.652 |
B+ | 9 | 4.32 | 4.31 | 0.27 | −0.72 | 1.40 | 3.77 | 4.71 | 0.92 | 0.429 |
C+ | 9 | 3.90 | 3.75 | 0.24 | 0.83 | −1.72 | 3.72 | 4.22 | 0.68 | |
A+ | 9 | 4.10 | 4.03 | 0.16 | 2.34 | 5.88 | 3.98 | 4.50 | 0.68 | |
B+ | 10 | 3.92 | 3.93 | 0.10 | −1.36 | 2.57 | 3.69 | 4.03 | 0.89 | 0.156 |
C+ | 9 | 3.88 | 3.96 | 0.18 | −0.60 | −1.67 | 3.64 | 4.08 | 0.81 | |
A+ | 10 | 4.22 | 4.27 | 0.22 | −0.55 | −0.37 | 3.82 | 4.55 | 0.94 | 0.568 |
B+ | 9 | 3.80 | 3.78 | 0.12 | 1.41 | 1.88 | 3.69 | 4.06 | 0.86 | 0.092 |
C+ | 8 | 3.82 | 3.87 | 0.15 | −0.26 | −1.92 | 3.64 | 4.00 | 0.86 | 0.111 |
A+ | 5 | 3.16 × 106 | 1.70 × 106 | 3.83 × 106 | 2.20 | 4.87 | 1.1 × 106 | 10 × 106 | 0.63 | |
B+ | 5 | 5.33 × 106 | 2.30 × 106 | 5.05 × 106 | 1.12 | −0.38 | 1.6 × 106 | 13 × 106 | 0.81 | 0.105 |
C+ | 4 | 1.40 × 107 | 1.45 × 107 | 5.14 × 106 | −0.54 | 1.55 | 7.3 × 106 | 19.8 × 106 | 0.96 | 0.774 |
A+ | 4 | 3.47 × 107 | 2.41 × 107 | 3.85 × 107 | 0.97 | −0.66 | 4.50 × 106 | 8.60 × 107 | 0.87 | 0.291 |
B+ | 5 | 1.27 × 108 | 1.49 × 108 | 6.30 × 107 | −1.01 | 1.39 | 2.81 × 107 | 1.96 × 108 | 0.93 | 0.597 |
C+ | 4 | 2.19 × 108 | 2.15 × 108 | 4.91 × 107 | 0.48 | 1.52 | 1.63 × 108 | 2.83 × 108 | 0.96 | 0.786 |
A+ | 4 | 2.53 × 106 | 2.50 × 106 | 1.77 × 106 | 0.01 | −5.96 | 1.00 × 106 | 4.15 × 106 | 0.75 | |
B+ | 4 | 6.00 × 106 | 5.50 × 106 | 2.45 × 106 | 0.54 | −2.94 | 4.00 × 106 | 9 × 106 | 0.86 | 0.262 |
C+ | 4 | 4.89 × 106 | 5.28 × 106 | 1.43 × 106 | −0.91 | −1.00 | 3.00 × 106 | 6 × 106 | 0.86 | 0.268 |
A+ | 4 | 7.25 × 104 | 6.50 × 104 | 4.65 × 104 | 0.56 | −2.48 | 3.00 × 104 | 1.30 × 105 | 0.92 | 0.519 |
B+ | 4 | 2.50 × 105 | 2.35 × 105 | 1.68 × 105 | 0.25 | −4.06 | 9.00 × 104 | 4.40 × 105 | 0.90 | 0.437 |
C+ | 4 | 3.48 × 105 | 2.75 × 105 | 1.63 × 105 | 1.94 | 3.77 | 2.50 × 105 | 5.90 × 105 | 0.72 |
Abbreviations: N: the number of measurements; M: mean; Me: median; SD: standard deviation; Sk: skewness, Kurt.: kurtosis; Min and Max: the lowest and highest value of the distribution; W: Shapiro-Wilk test result; p: significance level; A: functional coating (TiO2:Ag); B: base coating (TiO2); C: original state (uncoated wires); p<0.05 is marked in bold.
The variables under investigation include the pH level, the formation of S. mutans biofilms, and adhesion tests. Based on the data presented in Table 2 (studies with sucrose), it can be observed that the conducted tests did not provide sufficient evidence to reject the null hypothesis of normality for the empirical distribution being analyzed. The table includes the test results for pH level, the formation of
Within the 24-hour timeframe, notable disparities were observed between the adapted archwires (with functional and base coatings) and the control sample (lacking any coating) in both experiments (with and without sucrose). Because the testing duration was extended to 48 hours and 96 hours, the archwire endowed with coating A consistently yielded markedly elevated pH levels within the salivary milieu, when contrasted with the archwire treated with coating B and the uncoated wire. It is pertinent to observe that the significance threshold necessary for the rejection of the null hypothesis exhibited a remarkably elevated magnitude across all the aforementioned comparisons.
Following a 24-hour incubation period, it was noted that the pH of the salivary milieu exhibited a 5% elevation when contrasted with the control sample in the presence of the TiO2:Ag coating. Subsequently, at the 48-hour and 96-hour time points, a 4% increment in pH was discerned in the experimental group conducted in the absence of sucrose [32]. In the presence of sucrose, the TiO2:Ag coating caused a 9% increase in pH after 24 hours, followed by a 5% increase at 48 hours and a further 9% increase at 96 hours, as indicated in Figure 1.
The antiadhesive surface of orthodontic archwires, which is an important parameter for preventing microorganism colonization in the oral cavity, was evaluated after a 4-hour experiment.
In the case of the experiment without sucrose, one can see the strong significance of the difference in the averages in groups A and C (the significance level is far from the threshold level) in favor of the group with the active coating. Also worth noting is that there are differences between the other groups in this experiment but not significant.
For the sucrose experiments, a significant difference is seen between groups A and C, although, as we recall, such differences were not observed in the ANOVA test. A discussion of the significance of the differences in this case would be too farfetched (the Newman-Keuls test is simply more sensitive), but this figure leads us to conclude that there are significant differences in adhesion values for the groups indicated, with a lower value of this parameter observed for the samples with the active coating.
It is evident that sucrose loading has a clear effect on the reduction of adhesion. In each of the cases studied, samples with an applied active coating (A) show significantly lower adhesion than the reference samples (without any coating). In addition, samples with active coating allowed results with significantly less variation compared to the other groups.
Table 1S in the supplementary materials section) reveals a strong significance in the difference between groups A and C. The marked dissimilarity in outcomes lends a distinct advantage to the cohort endowed with the A coating. Nevertheless, it is imperative to underscore that the distinctions observed among the remaining experimental groups, while statistically significant, do not attain a magnitude of substantial significance. The A coating elicited a noteworthy 74% reduction in
Results of the Newman-Keuls post hoc test for the dependent variable of pH levels; experiment without sucrose
Group | {1} | {2} | {3} |
A {1} | 0.0678 | ||
B {2} | 0.0678 | ||
C {3} | |||
Group | {1} | {2} | {3} |
A {1} | |||
B {2} | 0.8958 | ||
C {3} | 0.8958 | ||
Group | {1} | {2} | {3} |
A {1} | |||
B {2} | 0.5474 | ||
C {3} | 0.5474 |
*Significant differences for p<0.05 are marked in bold.
Based on the data provided, it is discernible that the inclusion of the TiO2:Ag coating (A) engendered a diminution in bacterial adhesion when juxtaposed with the control specimen bereft of any coating (C) [32]. Furthermore, Figure 3S demonstrates that the biofilm formed on the TiO2:Ag coating (A) demonstrated signs of fragmentation and heightened vulnerability to detachment. In contrast, the biofilm on the uncoated archwire (C) exhibited the formation of three-dimensional clusters, enveloped by a bacterial matrix layer (Fig. 3S A+, B+, C+). It is possible that the presence of coating A hinders the formation of a durable and firmly attached bacterial biofilm on orthodontic wire, making it easier to remove during oral rinsing.
In the subsequent phase of analysis, an investigation was carried out to ascertain whether the presence of bacterial biofilms is affected by the coating applied on the surface of orthodontic archwires. In order to assess significant differences between pairs of data, the researchers utilized the Newman-Keuls post-hoc tests. The results of the Newman-Keuls test can be found in Table 1S (results without sucrose) and Table 2S (results with sucrose) in the supplementary materials section.
Results of the Newman-Keuls post hoc test for the dependent variable of pH levels; experiment with sucrose
Group | {1} | {2} | {3} |
A+ {1} | 0.9353 | ||
B+ {2} | 0.9353 | ||
C+ {3} | |||
Group | {1} | {2} | {3} |
A+ {1} | |||
B+ {2} | 0.5602 | ||
C+ {3} | 0.5602 | ||
Group | {1} | {2} | {3} |
A+ {1} | |||
B+ {2} | 0.7863 | ||
C+ {3} | 0.7863 |
*Significant differences for p<0.05 are marked in bold.
The application of a TiO2:Ag coating on the surface of the orthodontic archwire resulted in a substantial decrease in biofilm formation. After 24 hours, there was a notable reduction of 77% compared to the reference sample. This reduction further improved to 84% after 48 hours. However, after 96 hours, the reduction decreased to 48% when compared to the reference sample. In contrast, the TiO2 base coating exhibited a 62% decrease in biofilm formation after 24 hours. After 48 hours, the reduction decreased to 42%. Surprisingly, in the presence of sucrose, there was an unexpected increase of 23% in biofilm formation after 96 hours compared to the reference sample. These findings are illustrated in Figure 4S.
This study aimed to assess the antibacterial and antiadherent characteristics of stainless steel orthodontic archwires with surface modifications of TiO2 and TiO2:Ag in the presence of sucrose. The orthodontic archwires were manufactured from 304V stainless steel. The primary distinction between 304V and 304L stainless steel lies in their carbon content and intended use. While 304L has lower carbon content, enhancing its corrosion resistance in welded applications, 304V is a free-machining variant designed for improved machinability, making it suitable for applications where ease of machining is a priority. In the context of orthodontic archwires, 304V stainless steel is specifically designed for improved machinability, making it easier to shape and manipulate during the manufacturing process.
In an environment devoid of sucrose, the TiO2:Ag coating exhibited significant effects over a span of 24, 48, and 96 hours. After a 24-hour period, a discernible 5% elevation in the pH level of the synthetic saliva was observed in comparison to the control sample. Similarly, after both 48 and 96 hours, there was a 4% increase in pH. With respect to bacterial adhesion, the TiO2:Ag coating exhibited a substantial reduction of 74% in
The current investigation reveals that in a sucrose-rich environment, the survival rate of
The research findings revealed an intriguing pattern. Upon analyzing the results, it was observed that in a sucrose-rich environment, bacteria exhibited a reduced inclination to adhere to metal wires. However, the presence of carbohydrates led to a noteworthy decrease in the pH level throughout all the studied time intervals. In summary, the presence of sucrose diminished the propensity of
The research results demonstrate that the presence of sucrose in the environment leads to a significant decrease of 40%–60% in bacterial attachment to the wire surface. The extent of reduction in bacterial adhesion varies depending on the type of coating applied. This observation is supported by the data depicted in Figure 2S, which compares the experimental results with and without the inclusion of sucrose.
Previous research conducted by Boyd et al. [34] has shown that the presence of a high concentration of sucrose leads to a reduction in the adherence of
Takahashi et al. previously proposed the hypothesis that when a high sucrose concentration is present, the reduction of the pH in the surrounding environment exerts a more pronounced influence [31]. Sucrose is commonly found in the human oral environment as part of the diet and can influence bacterial adhesion, biofilm formation, and acidification of the surroundings. Consequently, the authors suggest that studies evaluating the antibacterial properties of coatings should also consider the presence of carbohydrates. Numerous existing studies have confirmed the antibacterial properties of TiO2 or TiO2:Ag coatings, but they have overlooked the potential impact of additional sucrose loading in their experimental designs [9, 35–37]. This oversight is significant as the presence of sucrose could potentially contribute to the development of dental caries. The researchers in this study have provided evidence to demonstrate that in the presence of sucrose, bacteria exhibit decreased abilities to adhere and form biofilms; however, they tend to acidify the surrounding environment to a greater extent. Furthermore, the introduction of silver nanoparticles significantly reduces the bacteria’s ability to adhere in the presence of sucrose, especially after 48 hours and 96 hours. This effect is more pronounced within the initial 24-hour period when sucrose is absent from the environment.
In summary, it can be deduced that the inclusion of sucrose leads to a considerable increase in acidity in the environment surrounding
Based on a clinical analysis of outcomes, it can be inferred that when individuals undertake measures to limit the effects of sucrose, such as modifying their diet and practicing oral hygiene, the functional coating is anticipated to offer an additional advantage. It is anticipated that the coating will effectively impede the capacity of
In considering avenues for future research, the intriguing observations and complexities uncovered in this study prompt the identification of several directions for further investigation. Given the pivotal role of orthodontic wires as medical devices, it is imperative to delve deeper into understanding the dynamics between coating compositions, environmental conditions, and bacterial responses. While our study provides valuable insights into the shortterm effects of coatings on bacterial adhesion and pH levels, a more extensive examination of the long-term durability and stability of these coatings is essential. Longitudinal studies could elucidate the sustained impact of functional coatings over extended durations, simulating the conditions that orthodontic wires encounter during the course of treatment. Transitioning from laboratory conditions to clinical applications is a crucial step. Future research should bridge the gap by conducting in vivo studies to validate the efficacy and safety of the TiO2:Ag coating in real-world orthodontic scenarios. Assessing its performance in the presence of diverse oral environments and patient-specific factors will contribute to the clinical translatability of the proposed intervention.
In considering the implications of our research and charting directions for future investigations, it becomes apparent that further mechanical testing is warranted to comprehensively evaluate the performance of orthodontic wires under the influence of different coatings. The incorporation of mechanical assessments, such as three-point bending tests, can provide valuable insights into the structural integrity and durability of the wires. This would contribute to a holistic understanding of the interplay between the functional coatings and the mechanical properties of orthodontic wires, ensuring their effectiveness and safety in a clinical context. Moreover, delving into the nanothickness and surface roughness of the coatings could unveil additional dimensions of their impact on bacterial adhesion and biofilm formation. Investigating these finer details at the nanoscale level could elucidate the intricate interactions between the coating properties and bacterial behavior. Nanostructural characteristics play a pivotal role in influencing the adhesion of microorganisms, and an in-depth exploration of these features can augment our comprehension of the underlying mechanisms governing the observed antibacterial effects.
In conclusion, these suggested directions for future research aim to propel the field of orthodontic materials towards enhanced functionality, longevity, and patient-centric outcomes. By addressing these research avenues, we can advance the understanding of orthodontic coatings and pave the way for transformative innovations in orthodontic care.
The method employed demonstrated efficacy when applied to orthodontic wires, resulting in the creation of a coating that exhibited effective antibacterial properties against The introduction of sucrose resulted in an average 30% reduction in the pH of the surroundings, as In the experimental setting, the addition of sucrose led to a noteworthy reduction of 40%–60% in the adherence of The application of a TiO2:Ag coating on the orthodontic archwire surface resulted in a noteworthy reduction in the formation of biofilm in an environment containing high levels of sucrose. After 24 hours, a decrease was observed in biofilm formation by 77% compared to the control sample. This reduction further increased to 84% after 48 hours and 48% after 96 hours, relative to the reference sample. In vitro studies have revealed that archwires coated with TiO2:Ag possess antibacterial properties, which consequently contribute to the prevention of caries and the accumulation of plaque.
The presence of sucrose in the environment leads to a notable increase in the acidification level of
The results of the post-hoc tests for the different experimental groups are shown in Tables 1S and 2S. As can easily be seen, after 24 h there are significant differences in the sucrose-free and sucrose-grown groups between the modified arcs (with active and base coating) and the reference sample (without coating). After longer testing times (48 h and 96 h), the active-coated sample induces a significantly higher pH in the environment than the base-coated and uncoated arcs. The significance level for rejecting the null hypothesis is very high in each of the comparisons indicted.
In the case of the experiment without sucrose, one can see the strong significance of the difference in the averages in groups A and C (the significance level is far from the threshold level) in favor of the group with the active coating. Also worth noting is that there are differences between the other groups in this experiment but not significant.
For the sucrose experiments, a significant difference is seen between groups A and C, although, as we recall, such differences were not observed in the ANOVA test. A discussion of the significance of the differences in this case would be too farfetched (the Newman-Keuls test is simply more sensitive), but this figure leads us to conclude that there are significant differences in adhesion values for the groups indicated, with a lower value of this parameter observed for the samples with the active coating.
Results of the Newman-Keuls post hoc test for bacterial cultures
Group | {1} | {2} | {3} |
A {1} | 0.0590 | ||
B {2} | 0.0590 | 0.0866 | |
C {3} | 0.0866 | ||
Group | {1} | {2} | {3} |
A+ {1} | 0.1012 | ||
B+ {2} | 0.1012 | 0.3420 | |
C+ {3} | 0.3420 |
*Significant differences for p<0.05 are marked in bold;
Results of the Newman-Keuls post hoc test for bacterial cultures, experiments without sucrose
Group | {1} | {2} | {3} |
A {1} | 0.0895 | ||
B {2} | 0.0895 | 0.0529 | |
C {3} | 0.0529 | ||
Group | {1} | {2} | {3} |
A {1} | 0.1159 | ||
B {2} | 0.1159 | ||
C {3} |
*Significant differences for p<0.05 are marked in bold.
It is evident that sucrose loading has a clear effect on the reduction of adhesion. In each of the cases studied, samples with an applied active coating (A) show significantly lower adhesion than the reference samples (without any coating). In addition, samples with active coating allowed results with significantly less variation compared to the other groups.
Results of the Newman-Keuls post hoc test for bacterial cultures, experiments with sucrose
Group | {1} | {2} | {3} |
A+ {1} | 0,4960 | ||
B+ {2} | 0.4960 | ||
C+ {3} | |||
Group | {1} | {2} | {3} |
A+ {1} | |||
B+ {2} | |||
C+ {3} | |||
Group | {1} | {2} | {3} |
A+ {1} | 0.0749 | 0.1198 | |
B+ {2} | 0.0749 | 0.4368 | |
C+ {3} | 0.1198 | 0.4368 |
*Significant differences for p<0.05 are marked in bold.