Evidence map›Paper›PMID 42487116›Full record

ArticleBMC oral health2026

Assessment of biofilm resistance, degree of conversion, and mechanical properties of nanomodified 3D-printed orthodontic clear aligner (in-vitro study).

Amal I Elnaggar, Amal E Fahmy, Nesrine F Hanafi, Salma Aboulgheit

Abstract read
In one paragraph

Article in BMC oral health, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Amal I ElnaggarDental Biomaterials Department, Faculty of Dentistry, University of Alexandria, Champollion Street - Azarita, Alexandria, 21521, Egypt. a.elnaggar164062.na@alexu.edu.eg.ORCID 0009-0009-0836-1998
Amal E FahmyDental Biomaterials Department, Faculty of Dentistry, University of Alexandria, Champollion Street - Azarita, Alexandria, 21521, Egypt.
Nesrine F HanafiMedical Microbiology and Immunology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
Salma AboulgheitDental Biomaterials Department, Faculty of Dentistry, University of Alexandria, Champollion Street - Azarita, Alexandria, 21521, Egypt.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThree-dimensional (3D)-printed orthodontic clear aligners represent a paradigm shift in malocclusion management; however, they remain susceptible to bacterial biofilm accumulation. Therefore, modification strategies that enhance resistance to biofilm accumulation without compromising mechanical performance are required. This study evaluated biofilm resistance, degree of conversion (DC%), flexural strength (FS), and surface microhardness (VHN) of commercially available 3D-printed clear aligner resin (CR) modified with nanozeolite (NZ) and chitosan nanoparticles (Chs NPs).

methodsA total of 432 3D-printed specimens were fabricated and allocated into six groups: Group I (control): CR; Group II: (CR + 0.25 wt% NZ); Group III: (CR + 0.5 wt% NZ); Group IV: (CR + 0.25 wt% Chs NPs); Group V: (CR + 0.5 wt% Chs NPs); and Group VI (hybrid): (CR + 0.25 wt% NZ + 0.25 wt% Chs NPs). Surface topography and chemical characterization were performed using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) for DC%. Biofilm resistance against Streptococcus mutans was assessed using a crystal violet assay by measuring optical density (OD) after 48-hour and 14-day incubation periods. FS and VHN were evaluated using a universal testing machine and a Vickers microhardness tester, respectively. All properties were evaluated before and after 14-day aging. Data were analyzed using two-way ANOVA and independent samples t-test with Bonferroni adjustment (α = 0.05).

resultsTwo-way ANOVA indicated that the interaction between nanoparticle content and aging significantly influenced the DC%, OD, FS, and VHN values (p < 0.001). The 0.25 wt% NZ group showed the lowest OD after 48 h, whereas the 0.5 wt% NZ group showed the lowest OD after 14 days. The hybrid group demonstrated the highest FS and VHN values before and after aging. DC% values remained comparable among most groups, except for the 0.5 wt% Chs NPs group, which exhibited significantly lower DC% values before aging. Overall, the 0.5 wt% NZ group demonstrated the most favorable balance between reduced biofilm biomass and mechanical performance.

conclusionsNanoparticle incorporation improves the functional properties of 3D-printed clear aligners. NZ-containing groups reduced Streptococcus mutans biofilm biomass while preserving acceptable mechanical performance, suggesting potential for development of biofilm-resistant aligner materials.

Indexed as

BiofilmsOrthodontic Appliances, RemovablePrinting, Three-DimensionalChitosanFlexural StrengthHardnessHumansIn Vitro TechniquesMaterials TestingMicroscopy, Electron, ScanningNanoparticlesStreptococcus mutansSurface PropertiesChitosan3D printingBiofilm resistanceDegree of conversionFlexural strengthOrthodontic clear alignerSurface microhardness

Identifiers

PMID42487116
PMCPMC13390215

What Socratic holds

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.