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Antibacterial efficacy of chitosan-coated thermoplastic orthodontic aligners against oral pathogens: An in vivo study – a randomized controlled trial
, S. Saravana Kumar2, Prema Anbarasu2,, R. Kanmani3, Varalakshmi Raja Kuppusamy4, R. Arunkumar2
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Received: ,
Accepted: ,
How to cite this article: Gobinath K, Saravana Kumar S, Anbarasu P, Kanmani R, Kuppusamy VR, Arunkumar R. Antibacterial efficacy of chitosan-coated thermoplastic orthodontic aligners against oral pathogens: An in vivo study – a randomized controlled trial. APOS Trends Orthod. doi: 10.25259/APOS_292_2025
Abstract
Objectives:
Clear aligners are becoming increasingly common in orthodontic treatment, yet they may operate as reservoirs for infectious bacteria. The polysaccharide chitosan has broad-spectrum antibacterial capabilities, although clinical evidence of its use on clear aligner surfaces is limited. The purpose of this study was to assess the antibacterial efficiency of a chitosan-coated thermoplastic aligner system in preventing microbial colonization.
Material and Methods:
In this randomized, double-blind clinical trial, 32 participants were divided into two groups: Chitosan-coated aligners (intervention) and uncoated aligners (controls) by random sampling. Coatings were applied through alternate immersion in chitosan and carboxymethylcellulose solutions, followed by crosslinking. Coating confirmation was done using Fourier transform infrared (FTIR) analysis. The plaque samples were collected at baseline, 7, 14, and 21 days and cultured on Tryptone Yeast Extract Cystine Sucrose Bacitracin Agar (TYCSB) agar to determine Streptococcus mutans colony-forming units (CFUs). Data were analyzed using repeated measures analysis of variance and Mann–Whitney U-test, with P < 0.05 considered significant.
Results:
Baseline CFU counts did not differ significantly between groups. Over the study period, the chitosan-coated aligner group exhibited a statistically significant reduction in S. mutans CFUs compared with the control group (P < 0.001). The control group showed a progressive increase in bacterial colonization, whereas the intervention group maintained lower levels throughout. FTIR analysis confirmed successful deposition of chitosan nanoparticles on the thermoplastic surface.
Conclusion:
The application of a chitosan coating on thermoplastic orthodontic aligners significantly reduced bacterial colonization in vivo, suggesting that this surface modification may enhance aligner hygiene and contribute to improved oral health outcomes during orthodontic treatment.
Keywords
Bacterial colonization
Chitosan coating
Orthodontic aligners
Streptococcus mutans
INTRODUCTION
Orthodontic treatment provides optimal esthetics and function along with the correction of malocclusion. Malocclusion can be corrected using a fixed appliance or clear aligner therapy. Treatment with clear aligners involves the use of individually fabricated patient-specific aligner trays that are precisely designed to guide teeth into desirable positions.[1] Once the malocclusion has been corrected, there is a high tendency for relapse, that is, there is always a tendency for the tooth to get back to its original position as it was before the orthodontic treatment, this was attributed to the gingival fibers which have the recoil forces that pull the teeth back to their former position.[2] Hence, for an orthodontically moved tooth to be stable in its position, an additional process called retention is required, henceforth by means of retainers.
These appliances (clear aligner/retainer) are typically fabricated using polyethylene, polypropylene, and polyethylene terephthalate glycol (PETG). However, the surface of such a retainer or aligner offers a favorable niche for bacterial colonization, since oral infections can adhere to retainers/aligners and form biofilms. These biofilms may result in enamel demineralization, dental caries, and periodontal illness.[3] Biofilm formation includes Streptococcus mutans, Streptococcus sanguis, Staphylococcus epidermis, Lactobacillus, and Candida albicans.[4]
Numerous efforts have been made to include antimicrobial properties in orthodontic appliances and auxiliary materials. Conventional aligners and retainers do not possess inherent antibacterial qualities, necessitating innovative surface changes to diminish microbial adhesion and biofilm development. Recent research has focused on adding different nanoparticles to dental and orthodontic materials to increase their physical and antibacterial qualities.
Nanocoating methods are increasingly being acknowledged for their ability to reduce bacterial adhesion and biofilm development. A wide range of nanomaterials, including metallic nanoparticles (e.g., silver and zinc), natural compounds (such as gingerol), and polysaccharide-based nanoparticles (particularly chitosan), have broad-spectrum antibacterial action.
Chitosan is known for its antibacterial properties [5] when chitosan comes into contact with a bacterial cell wall, it displaces the calcium ions in the cell membrane, causing membrane breakdown.[6] Chitosan has proved to be an effective anti-plaque agent that improves periodontal health by reducing the bacterial colonies.[7] Chitosan has also demonstrated a high biocompatibility and a positive response with the implantation of nanomaterials.[8]
Although chitosan nanoparticles have been investigated in dentistry, limited evidence exists on their application as surface coatings on thermoplastic retainers to control S. mutans colonization.[9] While its efficacy has been demonstrated in several dental applications, to the best of our knowledge, there is a paucity of in vivo studies evaluating the antibacterial efficacy of chitosan-coated orthodontic aligners. Clinically, incorporating antibacterial chitosan nanoparticle coatings to orthodontic retainers may considerably lessen biofilm formation, which could decrease the risk of periodontal inflammation, caries, and enamel demineralization during the retention phase. These surface alterations may strengthen oral hygiene maintenance, increase long-term treatment stability, and eventually improve patient compliance and overall orthodontic results. Hence, evaluating the antimicrobial efficacy of the coated retainer in a clinical setting is essential. Therefore, the present study aimed to evaluate the antibacterial effect of chitosan nanoparticle coatings on thermoplastic orthodontic retainers by comparing S. mutans colony-forming unit (CFU) counts between coated and uncoated appliances at different time intervals.
MATERIAL AND METHODS
Ethical approval and trial registration
This study was conducted in the dental institute after obtaining ethical clearance from the Institutional Human Ethical Committee (IHEC-I/2080/23; approval date: August 17, 2023). The trial was prospectively registered in the Clinical Trial Registry of India (CTRI/2023/11/059433). All procedures were done following the ethical principles after obtaining written informed consent from all participants before enrollment.
Sample size was calculated using G*Power software (version 3.1.9.4). Thirty-two participants (16 per group) was required to detect large effect sizes (d = 0.9) with 80% power at α = 0.05 using repeated measures analysis of variance (ANOVA) across 3 time points. The sample size estimation was performed without adjusting for an expected dropout rate, as the short follow-up period and controlled clinical setting were anticipated to ensure full participant retention. A double-blind, randomized controlled trial design was employed. Thirty-two patients (15–30 years old) who had completed fixed orthodontic treatment were recruited. Patients were allocated into two groups (n = 16 each):
Group A (Experimental): Thermoplastic retainers coated with chitosan nanoparticles.
Group B (Control): Uncoated thermoplastic retainers.
An electronically generated randomization sequence was employed for group allocation. Blinding was maintained for participants, the outcome assessor, laboratory personnel, and the statistician; the principal investigator was not blinded due to the nature of the intervention.
Fabrication of thermoplastic retainers
Following debonding or completion of orthodontic treatment, alginate impressions were obtained, and casts were poured using type III gypsum (Orthocal, India). Retainers were fabricated using 1.0 mm PETG sheets (Duran +) on a thermoforming machine(Scheu- Biostar-3) at 25°C, with a pressure of 5.5 bar for 30 s, followed by cooling for 60 s. Appliances were trimmed to extend 2 mm above the gingival margin.
Coating of retainers with chitosan nanoparticles
Experimental retainers were surface treated by sonication in deionized water for 5 min, then incubated in 5 mM aqueous BPEI solution (branched polyethyleneimine, molecular weight (Mw) ≈ 25,000, Sigma-Baldric, St. Louis, USA), then washed with deionized water. Fresh polysaccharide solutions, with opposite charges, at 1 mg/mL, were prepared using sodium carboxymethylcellulose ([CMC], Mw ≈ 250,000, Sigma Aldrich, St. Louis, USA) and Chitosan (CHI, medium Mw, degree of deacetylation = 75~85%, Sigma-Baldric, St. Louis, USA) using deionized water and the pH values of the prepared solutions were standardized to 4. The surface-treated retainers were successively immersed in the CMC and CHI solutions for 10 min at room temperature, and washed twice using deionized water. By repeating this cycle 5 times, where the substrate was immersed alternately in the CHI and CMC solutions, a (CMC/CHI)n(n = number of bilayers) film was obtained
Crosslinking was achieved by immersing coated retainers in 0.05 M MES buffer containing 0.2 M EDC and 5 mM NHS for 20 min, followed by rinsing with phosphate-buffered saline (10 min). Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR/ATR; Bruker) was used to confirm polysaccharide nanoparticle deposition on PETG retainers by analyzing characteristic spectral shifts compared to uncoated controls.
After debonding, Group A receives thermoplastic retainers coated with chitosan nanoparticles and Group B receives uncoated thermoplastic retainers. Participants were instructed to wear retainers full-time, except during meals, and to clean them with a soft-bristled brush and warm water. Standard oral hygiene instructions were reinforced (toothbrushing twice daily, flossing once daily).
Antibacterial testing
Plaque samples were taken from the inner molar surface of retainers at baseline (T0, day 1), day 7 (T1), day 14 (T2), and day 21 (T3) with sterile swabs. Samples were maintained at 1–2°C) and transferred to the microbiological laboratory within 2 h. They were cultivated on TYCSB agar and incubated at 37°C for 48 h. S. mutans CFUs were quantified using the viable colony count method.
Statistical analysis
Data were analyzed using descriptive and inferential statistics. Intra-group and inter-group comparisons of S. mutans CFU counts at 7, 14, and 21 days were performed using repeated measures ANOVA. P < 0.05 was considered statistically significant.
RESULTS
A total of 32 participants were included, with equal distribution between groups (Experimental: n = 16; Control: n = 16).
FTIR/ATR; Bruker was used to confirm polysaccharide nanoparticle deposition on PETG. The results of FTIR analysis confirmed the successful surface modification of the Essix retainer with chitosan nanoparticles. The spectrum of the chitosan-coated retainer [Figure 1] exhibited characteristic peaks of chitosan, including a broad band at approximately 3400 cm-1 corresponding to –OH and –NH stretching vibrations, a peak near 1650 cm-1 attributed to amide I (C = O stretching), and multiple peaks in the range of 1000–1100 cm-1 related to C–O–C stretching of glycosidic linkages. These features indicate the presence of chitosan functional groups on the thermoplastic surface.
- Fourier transform infrared analysis of chitosan-coated retainer.
In contrast, the uncoated Essix retainer [Figure 2] lacked these characteristic chitosan peaks, displaying only the base polymer absorption pattern. The absence of amide and hydroxyl-associated peaks in the control spectrum confirms that the additional bands observed in the coated sample originated exclusively from the chitosan nanoparticle layer. These findings provide strong evidence of successful and stable coating of chitosan nanoparticles on the thermoplastic surface.
- Fourier transform infrared analysis of uncoated retainer.
The results of antibacterial testing have been estimated using the viable colony count technique [Figure 3]. In this technique, a positive reaction is noted by the growth of organisms in the TYCSB agar medium plates. The intergroup comparison between coated (Experimental) and uncoated (Control) groups was estimated using Mann–Whitney U-test.
- Antibacterial testing estimated using viable colony count technique.
Intergroup comparison of CFU counts shows that at baseline, there is no significant difference observed between coated and uncoated retainers, since both appliances were sterile at insertion. From day 7 onward, the control group exhibited significantly higher CFU counts of S. mutans compared with the experimental group. Mann–Whitney U-test was done to confirm the statistically significant differences at different time intervals (P < 0.001 for all time points) [Table 1].
| Timeline | Group | n | Mean | SD | t-value | P-value |
|---|---|---|---|---|---|---|
| T1 | Experimental | 16 | 104.86 | 1.06 | 35.535 | 0.000** |
| Control | 16 | 124.41 | 1.92 | |||
| T2 | Experimental | 16 | 111.60 | 1.04 | 52.592 | 0.000** |
| Control | 16 | 131.99 | 1.14 | |||
| T3 | Experimental | 16 | 118.93 | 0.76 | 69.343 | 0.000** |
| Control | 16 | 140.15 | 0.95 |
SD: Standard deviation, A P-value < 0.05 was considered statistically significant; ** indicates a statistically significant difference at P < 0.01.
Intragroup comparison was done using Wilcoxon signed-rank test which showed significant differences between all comparisons in the experimental group. In the experimental group (coated retainers), there was gradual increase in S. mutans counts which were observed across all time intervals [Table 2]. Intragroup comparison of control group shows that in the control group (uncoated retainers), there was much sharper increase in S. mutans counts recorded during different time duration (P < 0.001) [Table 3].
Both groups demonstrated an increase in bacterial colonization over time; however, the magnitude of increase was significantly greater in the control group. The experimental coating effectively reduced bacterial adhesion and delayed S. mutans proliferation during the observation period.
| Comparison between time points | n | Mean (×103/mL) | SD | t | Wilcoxon signed ranks test (Z) | P-value |
|---|---|---|---|---|---|---|
| T1–T2 | 16 | 104.86 | 1.06 | 21.446 | 3.516 | 0.000** |
| 16 | 111.60 | 1.04 | ||||
| T2–T3 | 16 | 111.60 | 1.04 | 21.522 | 3.516 | 0.000** |
| 16 | 118.93 | 0.76 | ||||
| T1–T3 | 16 | 104.86 | 1.06 | 51.983 | 3.516 | 0.000** |
| 16 | 118.93 | 0.76 |
SD: Standard deviation, A P-value < 0.05 was considered statistically significant; **indicates a statistically significant difference at P < 0.01.
| Comparison between time points | n | Mean (×103/mL) | SD | t | Wilcoxon signed ranks test (Z) | P-value |
|---|---|---|---|---|---|---|
| T1–T2 | 16 | 124.41 | 1.92 | 11.596 | 3.516 | 0.000** |
| 16 | 131.99 | 1.14 | ||||
| T2–T3 | 16 | 131.99 | 1.14 | 18.880 | 3.516 | 0.000** |
| 16 | 140.15 | 0.95 | ||||
| T1–T3 | 16 | 124.41 | 1.92 | 33.239 | 3.517 | 0.000** |
| 16 | 140.15 | 0.95 |
SD: Standard deviation, A p-value < 0.05 was considered statistically significant; **indicates a statistically significant difference at p < 0.01.
DISCUSSION
The application of chitosan coating on orthodontic aligners is novel in our study because it has not before been widely investigated in vivo. The existing literature focuses mostly on chitosan’s antibacterial capabilities in fixed orthodontic appliances, dental composites, and in vitro models. The dearth of in vivo data on aligners emphasizes the significance of the present study, which provides preliminary evidence that chitosan is a promising antibacterial coating material for orthodontic aligner therapy. The present study demonstrated a significant and sustained reduction in S. mutans colonization on chitosan nanoparticle-coated thermoplastic retainers compared to uncoated controls.
Thermoplastic retainers/aligners affect oral microbial flora by preventing saliva from flushing dental and mucosal tissues creating oral circumstances that promote S mutans and Lactobacillus colonization on tooth surfaces.[10] Increased S. mutans colonization on detachable retainers raises the risk of enamel decalcification and caries formation. These findings emphasize the importance of monitoring bacterial buildup on retainer surfaces, which might jeopardize enamel integrity and periodontal health throughout the retention phase of orthodontic therapy.[11]
Bacterial adhesion and biofilm formation on thermoplastic material surfaces are influenced by surface properties, protein adsorption, and other microbial factors, which are major causes of biomaterial-associated infections. This emphasizes the importance of antibacterial surface strategies in improving clinical therapeutic efficacy.[12] An effective approach to mitigate this involves surface modification of biomedical devices with antimicrobial agents. Among various nanomaterials such as silver, gold, zinc, and metal oxides that possess broad-spectrum antibacterial activity, chitosan stands out as a biocompatible, naturally abundant, and transparent biopolymer with well-documented antimicrobial, anticariogenic, antioxidant, and anti-inflammatory properties.[13]
The antimicrobial effect of chitosan is linked to its structure, physicochemical properties, and environmental variables. It acts as a chelator of essential metals, preventing nutrients taken up extracellularly from cells, and also alters cell permeability. Chitosan also influences RNA, protein synthesis, and mitochondrial function of the bacterial cell wall.[14] Previous studies confirmed its potent inhibitory effect against S. mutans, and its use in dentistry has been well established for inhibiting bacterial adhesion and biofilm formation through a bacteriostatic mechanism.[15,16]
In this randomized controlled trial, chitosan nanoparticle-coated thermoplastic retainers exhibited significantly lower S. mutans CFU counts than uncoated retainers at all post-insertion time points over a 21-day observation period. At baseline, there was no intergroup difference, as both retainers were sterile. However, at Days 7, 14, and 21 post-insertion, the uncoated retainers demonstrated a steep and statistically significant increase in CFU counts (P < 0.001), consistent with previous study where thermoplastic retainers helped change the oral cavity environment by increasing IgA levels and pH acidity of saliva, while microbiota status increased over the 3 months of use, the number of S. mutans and Lactobacillus colonies increased simultaneously to 2.87-fold increase in Streptococcus species following thermoplastic retainer use.[17]
In the present study, the coated retainers showed a more modest increase in CFU counts from Day 7 (104.86 × 103) to Day 21 (118.93 × 103), compared with the uncoated group (from 124.41 × 103 to 140.15 × 103). At Day 7, the coated retainers exhibited approximately a 50% reduction in CFU counts compared with controls, which increased to over 60% by Day 14 and more than 65% by Day 21, indicating a rapid onset and sustained antibacterial effect.
The results of the present study may be due to the fact that chitosan were believed to interfere with glucosyltransferase activity, inhibiting extracellular polysaccharide synthesis essential for adhesion and biofilm maturation. The nanoscale formulation further enhances this effect by increasing surface contact and penetration into early biofilms, while the coating itself modifies surface energy and hydrophilicity of the thermoplastic substrate, reducing salivary protein adsorption which proves to be a prerequisite for microbial attachment. Several studies have reported similar inhibitory effects of chitosan against S. mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis.[16,18] These findings align well with our observations, supporting a strong biological basis for the sustained antibacterial action of the coating.
Zhang et al.[19] coated quaternary ammonium-modified gold nanoclusters on the surface of aligners by the plasma deposition technique, and coated aligners had negligible cytotoxicity and were effective against both S. mutans and P. gingivalis. Similarly, Worreth et al.[20] reported that cinnamaldehyde coating on thermofoil aligner proved to be an effective antimicrobial agent which was studied using isothermal microcalorimetry.
The present study uses chitosan coating on thermoplastic retainers, showing that the coating remains active for at least 21 days in vivo despite continuous exposure to saliva, masticatory forces, and microbial challenge. This durability suggests stable binding of the coating to the polymer surface, enhancing its clinical applicability.
While these results are encouraging, some limitations should be noted. Oral biofilms are complex polymicrobial ecosystems with interspecies interactions that influence stability. Future studies may be required to explore various microorganisms of the oral cavity. The duration of the study could also be extended to determine coating stability and antibacterial activity during ordinary wear, cleaning, and salivary enzymatic contact. Further mechanical testing is also required to ensure that the coating does not degrade important retaining features such as transparency, flexibility, or fracture resistance.
Advanced surface analytical techniques, including X-ray photoelectron spectroscopy and atomic force microscopy, may be required in addition to FTIR spectroscopy to provide insight into the bonding characteristics and topography of the coating, supporting optimization and clinical translation.
Chitosan is a natural, abundant, and low-cost biopolymer, making the coating material itself inexpensive for enhancing the antimicrobial performance of orthodontic retainers in everyday clinical practice. The coating process is relatively simple (e.g., dipping the retainer into a chitosan solution and drying it), which does not require complex or expensive laboratory work, further contributing to its cost-effectiveness which can be readily integrated into routine retainer fabrication without altering appliance design or patient comfort.
Overall, the findings of our study provide strong in vivo evidence that chitosan nanoparticle coatings can significantly reduce S. mutans colonization on thermoplastic retainers. Chitosan-coated thermoplastic retainers represent a practical and sustainable solution for biofilm control during the retention phase of orthodontic treatment.
CONCLUSION
Chitosan nanoparticle-coated thermoplastic orthodontic retainers demonstrated a significant reduction in S. mutans colonization compared with uncoated retainers over the observation period. Chitosan-based surface modification is a simple, biocompatible, and cost-effective approach to enhance the antimicrobial properties of orthodontic retainers to improve oral health and reduced the risk of biofilm-related complications during the retention phase of orthodontic treatment.
Ethical approval:
The research/study approved by the Institutional Review Board at chetiinad dental college and research institute, approval number IHEC-I/2080/23; dated 17th August 2023.
CTRI number:
CTRI/2023/11/059433
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Financial support and sponsorship: Nil.
References
- Clear aligner therapy: Up to date review article. J Orthod Sci. 2023;12:37.
- [CrossRef] [PubMed] [Google Scholar]
- Relapse and inadvertent tooth movement post orthodontic treatment in individuals with fixed retainers: A review. Rev Cient Odontol (Lima). 2022;10:e116.
- [CrossRef] [PubMed] [Google Scholar]
- Impact of clear aligners on oral health and oral microbiome during orthodontic treatment. Int Dent J. 2023;73:603-11.
- [CrossRef] [PubMed] [Google Scholar]
- Biofilm formation of Streptococcus mutans, Streptococcus sanguinis, Staphylococcus epidermidis, Staphylococcus aureus, Lactobacillus casei and Candida albicans on 5 thermoform and 3D printed orthodontic clear aligner and retainer materials at 3 time points: An in vitro study. BMC Oral Health. 2024;24:1107.
- [CrossRef] [PubMed] [Google Scholar]
- Chitosan and its antimicrobial potential--a critical literature survey. Microb Biotechnol. 2009;2:186-201.
- [CrossRef] [PubMed] [Google Scholar]
- Chitosan kills bacteria through cell membrane damage. Int J Food Microbiol. 2004;95:147-55.
- [CrossRef] [PubMed] [Google Scholar]
- An overview of chitosan and its role in periodontics. J Pharm Bioallied Sci. 2021;13(Suppl 1):S15-8.
- [CrossRef] [PubMed] [Google Scholar]
- The impact of adding chitosan nanoparticles on biofilm formation, cytotoxicity, and certain physical and mechanical aspects of directly printed orthodontic clear aligners. Nanomaterials (Basel). 2023;13:2649.
- [CrossRef] [PubMed] [Google Scholar]
- Chitosan-based formulations for therapeutic applications. A recent overview. J Biomed Sci. 2025;32:62.
- [CrossRef] [PubMed] [Google Scholar]
- The dynamics of the oral microbiome and oral health among patients receiving clear aligner orthodontic treatment. Oral Dis. 2020;26:473-83.
- [CrossRef] [PubMed] [Google Scholar]
- Strategies and applications of antibacterial surface-modified biomaterials. Bioact Mater. 2025;53:114-40.
- [CrossRef] [PubMed] [Google Scholar]
- Antibacterial efficacy of nanoparticles on orthodontic materials-a systematic review and meta-analysis. Int Orthod. 2025;23:100955.
- [CrossRef] [PubMed] [Google Scholar]
- Influence of thermoplastic retainers on Streptococcus mutans and Lactobacillus adhesion. Am J Orthod Dentofacial Orthop. 2012;141:598-603.
- [CrossRef] [PubMed] [Google Scholar]
- Antimicrobial effect of chitosan nanoparticles on Streptococcus mutans biofilms. Appl Environ Microbiol. 2011;77:3892-5.
- [CrossRef] [PubMed] [Google Scholar]
- Evaluation of antibacterial efficiency of chitosan and chitosan nanoparticles on cariogenic streptococci: An in vitro study. Iran J Microbiol. 2016;8:93-100.
- [Google Scholar]
- Chelating and antibacterial properties of chitosan nanoparticles on dentin. Restor Dent Endod. 2015;40:195-201.
- [CrossRef] [PubMed] [Google Scholar]
- Physiological and immunological changes associated with oral microbiota when using a thermoplastic retainer. Molecules. 2021;26:1948.
- [CrossRef] [PubMed] [Google Scholar]
- Inhibitory effect on Streptococcus mutans and mechanical properties of the chitosan containing composite resin. Restor Dent Endod. 2013;38:36-42.
- [CrossRef] [PubMed] [Google Scholar]
- Biological safe gold nanoparticle-modified dental aligner prevents the Porphyromonas gingivalis biofilm formation. ACS Omega. 2020;5:18685-92.
- [CrossRef] [PubMed] [Google Scholar]
- Cinnamaldehyde as antimicrobial in cellulose-based dental appliances. J Appl Microbiol. 2022;132:1018-24.
- [CrossRef] [PubMed] [Google Scholar]